[dev.link] all: merge branch 'master' into dev.link

Clean merge.

Change-Id: Ib773b0bc00fd99d494f9331c3613bcc8285e48e3

api/next.txt

@@ -3,3 +3,17 @@ pkg unicode, var Chorasmian *RangeTable
 pkg unicode, var Dives_Akuru *RangeTable
 pkg unicode, var Khitan_Small_Script *RangeTable
 pkg unicode, var Yezidi *RangeTable
+pkg text/template/parse, const NodeComment = 20
+pkg text/template/parse, const NodeComment NodeType
+pkg text/template/parse, const ParseComments = 1
+pkg text/template/parse, const ParseComments Mode
+pkg text/template/parse, method (*CommentNode) Copy() Node
+pkg text/template/parse, method (*CommentNode) String() string
+pkg text/template/parse, method (CommentNode) Position() Pos
+pkg text/template/parse, method (CommentNode) Type() NodeType
+pkg text/template/parse, type CommentNode struct
+pkg text/template/parse, type CommentNode struct, Text string
+pkg text/template/parse, type CommentNode struct, embedded NodeType
+pkg text/template/parse, type CommentNode struct, embedded Pos
+pkg text/template/parse, type Mode uint
+pkg text/template/parse, type Tree struct, Mode Mode

doc/asm.html

@@ -687,6 +687,13 @@ MOVQ	g(CX), AX     // Move g into AX.
 MOVQ	g_m(AX), BX   // Move g.m into BX.
 </pre>
 
+<p>
+Register <code>BP</code> is callee-save.
+The assembler automatically inserts <code>BP</code> save/restore when frame size is larger than zero.
+Using <code>BP</code> as a general purpose register is allowed,
+however it can interfere with sampling-based profiling.
+</p>
+
 <h3 id="arm">ARM</h3>
 
 <p>

doc/go1.14.html

@@ -609,6 +609,12 @@ Do not send CLs removing the interior tags from such phrases.
       If a program needs to accept invalid numbers like the empty string,
       consider wrapping the type with <a href="/pkg/encoding/json/#Unmarshaler"><code>Unmarshaler</code></a>.
     </p>
+
+    <p><!-- CL 200237 -->
+      <a href="/pkg/encoding/json/#Unmarshal"><code>Unmarshal</code></a>
+      can now support map keys with string underlying type which implement
+      <a href="/pkg/encoding/#TextUnmarshaler"><code>encoding.TextUnmarshaler</code></a>.
+    </p>
   </dd>
 </dl><!-- encoding/json -->
 

doc/go1.16.html

@@ -43,6 +43,37 @@ Do not send CLs removing the interior tags from such phrases.
 
 <h3 id="go-command">Go command</h3>
 
+<p><!-- golang.org/issue/24031 -->
+  <code>retract</code> directives may now be used in a <code>go.mod</code> file
+  to indicate that certain published versions of the module should not be used
+  by other modules. A module author may retract a version after a severe problem
+  is discovered or if the version was published unintentionally.<br>
+  TODO: write and link to section in golang.org/ref/mod<br>
+  TODO: write and link to tutorial or blog post
+</p>
+
+<p><!-- golang.org/issue/29062 -->
+  When using <code>go test</code>, a test that
+  calls <code>os.Exit(0)</code> during execution of a test function
+  will now be considered to fail.
+  This will help catch cases in which a test calls code that calls
+  os.Exit(0) and thereby stops running all future tests.
+  If a <code>TestMain</code> function calls <code>os.Exit(0)</code>
+  that is still considered to be a passing test.
+</p>
+
+<h4 id="all-pattern">The <code>all</code> pattern</h4>
+
+<p><!-- golang.org/cl/240623 -->
+  When the main module's <code>go.mod</code> file
+  declares <code>go</code> <code>1.16</code> or higher, the <code>all</code>
+  package pattern now matches only those packages that are transitively imported
+  by a package or test found in the main module. (Packages imported by <em>tests
+  of</em> packages imported by the main module are no longer included.) This is
+  the same set of packages retained
+  by <code>go</code> <code>mod</code> <code>vendor</code> since Go 1.11.
+</p>
+
 <p>
   TODO
 </p>
@@ -90,6 +121,28 @@ Do not send CLs removing the interior tags from such phrases.
   TODO
 </p>
 
+<h3 id="net"><a href="/pkg/net/">net</a></h3>
+
+<p><!-- CL 250357 -->
+  The case of I/O on a closed network connection, or I/O on a network
+  connection that is closed before any of the I/O completes, can now
+  be detected using the new <a href="/pkg/net/#ErrClosed">ErrClosed</a> error.
+  A typical use would be <code>errors.Is(err, net.ErrClosed)</code>.
+  In earlier releases the only way to reliably detect this case was to
+  match the string returned by the <code>Error</code> method
+  with <code>"use of closed network connection"</code>.
+</p>
+
+
+<h3 id="text/template/parse"><a href="/pkg/text/template/parse/">text/template/parse</a></h3>
+
+<p><!-- CL 229398, golang.org/issue/34652 -->
+  A new <a href="/pkg/text/template/parse/#CommentNode"><code>CommentNode</code></a>
+  was added to the parse tree. The <a href="/pkg/text/template/parse/#Mode"><code>Mode</code></a>
+  field in the <code>parse.Tree</code> enables access to it.
+</p>
+<!-- text/template/parse -->
+
 <h3 id="unicode"><a href="/pkg/unicode/">unicode</a></h3>
 
 <p><!-- CL 248765 -->
@@ -112,3 +165,27 @@ Do not send CLs removing the interior tags from such phrases.
 <p>
   TODO
 </p>
+
+<dl id="net/http"><dt><a href="/pkg/net/http/">net/http</a></dt>
+  <dd>
+    <p><!-- CL 233637 -->
+      In the <a href="/pkg/net/http/"><code>net/http</code></a> package, the
+      behavior of <a href="/pkg/net/http/#StripPrefix"><code>StripPrefix</code></a>
+      has been changed to strip the prefix from the request URL's
+      <code>RawPath</code> field in addition to its <code>Path</code> field.
+      In past releases, only the <code>Path</code> field was trimmed, and so if the
+      request URL contained any escaped characters the URL would be modified to
+      have mismatched <code>Path</code> and <code>RawPath</code> fields.
+      In Go 1.16, <code>StripPrefix</code> trims both fields.
+      If there are escaped characters in the prefix part of the request URL the
+      handler serves a 404 instead of its previous behavior of invoking the
+      underlying handler with a mismatched <code>Path</code>/<code>RawPath</code> pair.
+    </p>
+
+    <p><!-- CL 252497 -->
+     The <a href="/pkg/net/http/"><code>net/http</code></a> package now rejects HTTP range requests
+     of the form <code>"Range": "bytes=--N"</code> where <code>"-N"</code> is a negative suffix length, for
+     example <code>"Range": "bytes=--2"</code>. It now replies with a <code>416 "Range Not Satisfiable"</code> response.
+    </p>
+  </dd>
+</dl><!-- net/http -->

doc/install-source.html

@@ -600,6 +600,9 @@ The valid combinations of <code>$GOOS</code> and <code>$GOARCH</code> are:
 <td></td><td><code>linux</code></td> <td><code>mips64le</code></td>
 </tr>
 <tr>
+<td></td><td><code>linux</code></td> <td><code>riscv64</code></td>
+</tr>
+<tr>
 <td></td><td><code>linux</code></td> <td><code>s390x</code></td>
 </tr>
 <tr>

misc/cgo/test/test.go

@@ -319,6 +319,7 @@ typedef enum {
 
 // issue 4339
 // We've historically permitted #include <>, so test it here.  Issue 29333.
+// Also see issue 41059.
 #include <issue4339.h>
 
 // issue 4417

misc/wasm/wasm_exec.js

@@ -11,6 +11,7 @@
 	// - Node.js
 	// - Electron
 	// - Parcel
+	// - Webpack
 
 	if (typeof global !== "undefined") {
 		// global already exists
@@ -28,7 +29,7 @@
 
 	if (!global.fs && global.require) {
 		const fs = require("fs");
-		if (Object.keys(fs) !== 0) {
+		if (typeof fs === "object" && fs !== null && Object.keys(fs).length !== 0) {
 			global.fs = fs;
 		}
 	}
@@ -556,6 +557,7 @@
 	}
 
 	if (
+		typeof module !== "undefined" &&
 		global.require &&
 		global.require.main === module &&
 		global.process &&

src/cmd/asm/internal/asm/testdata/arm64.s

@@ -145,6 +145,37 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $-8
 	VZIP2	V10.D2, V13.D2, V3.D2           // a379ca4e
 	VZIP1	V17.S2, V4.S2, V26.S2           // 9a38910e
 	VZIP2	V25.S2, V14.S2, V25.S2          // d979990e
+	VUXTL	V30.B8, V30.H8                  // dea7082f
+	VUXTL	V30.H4, V29.S4                  // dda7102f
+	VUXTL	V29.S2, V2.D2                   // a2a7202f
+	VUXTL2	V30.H8, V30.S4                  // dea7106f
+	VUXTL2	V29.S4, V2.D2                   // a2a7206f
+	VUXTL2	V30.B16, V2.H8                  // c2a7086f
+	VBIT	V21.B16, V25.B16, V4.B16        // 241fb56e
+	VBSL	V23.B16, V3.B16, V7.B16         // 671c776e
+	VCMTST	V2.B8, V29.B8, V2.B8            // a28f220e
+	VCMTST	V2.D2, V23.D2, V3.D2            // e38ee24e
+	VSUB	V2.B8, V30.B8, V30.B8           // de87222e
+	VUZP1	V0.B8, V30.B8, V1.B8            // c11b000e
+	VUZP1	V1.B16, V29.B16, V2.B16         // a21b014e
+	VUZP1	V2.H4, V28.H4, V3.H4            // 831b420e
+	VUZP1	V3.H8, V27.H8, V4.H8            // 641b434e
+	VUZP1	V28.S2, V2.S2, V5.S2            // 45189c0e
+	VUZP1	V29.S4, V1.S4, V6.S4            // 26189d4e
+	VUZP1	V30.D2, V0.D2, V7.D2            // 0718de4e
+	VUZP2	V0.D2, V30.D2, V1.D2            // c15bc04e
+	VUZP2	V30.D2, V0.D2, V29.D2           // 1d58de4e
+	VUSHLL	$0, V30.B8, V30.H8              // dea7082f
+	VUSHLL	$0, V30.H4, V29.S4              // dda7102f
+	VUSHLL	$0, V29.S2, V2.D2               // a2a7202f
+	VUSHLL2	$0, V30.B16, V2.H8              // c2a7086f
+	VUSHLL2	$0, V30.H8, V30.S4              // dea7106f
+	VUSHLL2	$0, V29.S4, V2.D2               // a2a7206f
+	VUSHLL	$7, V30.B8, V30.H8              // dea70f2f
+	VUSHLL	$15, V30.H4, V29.S4             // dda71f2f
+	VUSHLL2	$31, V30.S4, V2.D2              // c2a73f6f
+	VBIF	V0.B8, V30.B8, V1.B8            // c11fe02e
+	VBIF	V30.B16, V0.B16, V2.B16         // 021cfe6e
 	MOVD	(R2)(R6.SXTW), R4               // 44c866f8
 	MOVD	(R3)(R6), R5                    // MOVD	(R3)(R6*1), R5                  // 656866f8
 	MOVD	(R2)(R6), R4                    // MOVD	(R2)(R6*1), R4                  // 446866f8
@@ -186,6 +217,10 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $-8
 	FMOVS	$(0.96875), F3                  // 03f02d1e
 	FMOVD	$(28.0), F4                     // 0490671e
 
+// move a large constant to a Vd.
+	FMOVD	$0x8040201008040201, V20         // FMOVD	$-9205322385119247871, V20
+	FMOVQ	$0x8040201008040202, V29         // FMOVQ	$-9205322385119247870, V29
+
 	FMOVS	(R2)(R6), F4       // FMOVS (R2)(R6*1), F4    // 446866bc
 	FMOVS	(R2)(R6<<2), F4                               // 447866bc
 	FMOVD	(R2)(R6), F4       // FMOVD (R2)(R6*1), F4    // 446866fc
@@ -359,18 +394,22 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $-8
 	VLD4	(R15), [V10.H4, V11.H4, V12.H4, V13.H4]         // ea05400c
 	VLD4.P	32(R24), [V31.B8, V0.B8, V1.B8, V2.B8]          // 1f03df0c
 	VLD4.P	(R13)(R9), [V14.S2, V15.S2, V16.S2, V17.S2]     // VLD4.P	(R13)(R9*1), [V14.S2,V15.S2,V16.S2,V17.S2] // ae09c90c
-	VLD1R	(R0), [V0.B16]					// 00c0404d
+	VLD1R	(R1), [V9.B8]                                   // 29c0400d
-	VLD1R.P	16(R0), [V0.B16]				// 00c0df4d
+	VLD1R.P	(R1), [V9.B8]                                   // 29c0df0d
-	VLD1R.P	(R15)(R1), [V15.H4]				// VLD1R.P	(R15)(R1*1), [V15.H4] // efc5c10d
+	VLD1R.P	1(R1), [V2.B8]                                  // 22c0df0d
-	VLD2R	(R15), [V15.H4, V16.H4]				// efc5600d
+	VLD1R.P	2(R1), [V2.H4]                                  // 22c4df0d
-	VLD2R.P	32(R0), [V0.D2, V1.D2]				// 00ccff4d
+	VLD1R	(R0), [V0.B16]                                  // 00c0404d
-	VLD2R.P	(R0)(R5), [V31.D1, V0.D1]			// VLD2R.P	(R0)(R5*1), [V31.D1, V0.D1] // 1fcce50d
+	VLD1R.P	(R0), [V0.B16]                                  // 00c0df4d
-	VLD3R	(RSP), [V31.S2, V0.S2, V1.S2]			// ffeb400d
+	VLD1R.P	(R15)(R1), [V15.H4]                             // VLD1R.P	(R15)(R1*1), [V15.H4] // efc5c10d
-	VLD3R.P	24(R15), [V15.H4, V16.H4, V17.H4]		// efe5df0d
+	VLD2R	(R15), [V15.H4, V16.H4]                         // efc5600d
-	VLD3R.P	(R15)(R6), [V15.H8, V16.H8, V17.H8]		// VLD3R.P	(R15)(R6*1), [V15.H8, V16.H8, V17.H8] // efe5c64d
+	VLD2R.P	16(R0), [V0.D2, V1.D2]                          // 00ccff4d
-	VLD4R	(R0), [V0.B8, V1.B8, V2.B8, V3.B8]		// 00e0600d
+	VLD2R.P	(R0)(R5), [V31.D1, V0.D1]                       // VLD2R.P	(R0)(R5*1), [V31.D1, V0.D1] // 1fcce50d
-	VLD4R.P	64(RSP), [V31.S4, V0.S4, V1.S4, V2.S4]		// ffebff4d
+	VLD3R	(RSP), [V31.S2, V0.S2, V1.S2]                   // ffeb400d
-	VLD4R.P	(R15)(R9), [V15.H4, V16.H4, V17.H4, V18.H4]	// VLD4R.P	(R15)(R9*1), [V15.H4, V16.H4, V17.H4, V18.H4] // efe5e90d
+	VLD3R.P	6(R15), [V15.H4, V16.H4, V17.H4]                // efe5df0d
+	VLD3R.P	(R15)(R6), [V15.H8, V16.H8, V17.H8]             // VLD3R.P	(R15)(R6*1), [V15.H8, V16.H8, V17.H8] // efe5c64d
+	VLD4R	(R0), [V0.B8, V1.B8, V2.B8, V3.B8]              // 00e0600d
+	VLD4R.P	16(RSP), [V31.S4, V0.S4, V1.S4, V2.S4]          // ffebff4d
+	VLD4R.P	(R15)(R9), [V15.H4, V16.H4, V17.H4, V18.H4]     // VLD4R.P	(R15)(R9*1), [V15.H4, V16.H4, V17.H4, V18.H4] // efe5e90d
 	VST1.P	[V24.S2], 8(R2)                                 // 58789f0c
 	VST1	[V29.S2, V30.S2], (R29)                         // bdab000c
 	VST1	[V14.H4, V15.H4, V16.H4], (R27)                 // 6e67000c

src/cmd/asm/internal/asm/testdata/arm64enc.s

@@ -591,7 +591,7 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$-8
    FMOVS R8, F15                              // 0f01271e
    FMOVD F2, F9                               // 4940601e
    FMOVS F4, F27                              // 9b40201e
-   //TODO VFMOV $3.125, V8.2D                 // 28f5006f
+   //TODO VFMOV $3.125, V8.D2                 // 28f5006f
    FMSUBS F13, F21, F13, F19                  // b3d50d1f
    FMSUBD F11, F7, F15, F31                   // ff9d4b1f
    //TODO VFMUL V9.S[2], F21, F19             // b39a895f
@@ -648,7 +648,7 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$-8
    FSUBS F25, F23, F0                         // e03a391e
    FSUBD F11, F13, F24                        // b8396b1e
    //TODO SCVTFSS F30, F20                    // d4db215e
-   //TODO VSCVTF V7.2S, V17.2S                // f1d8210e
+   //TODO VSCVTF V7.S2, V17.S2                // f1d8210e
    SCVTFWS R3, F16                            // 7000221e
    SCVTFWD R20, F4                            // 8402621e
    SCVTFS R16, F12                            // 0c02229e

src/cmd/asm/internal/asm/testdata/arm64error.s

@@ -339,4 +339,18 @@ TEXT errors(SB),$0
 	MRS	ICV_EOIR1_EL1, R3                                // ERROR "system register is not readable"
 	MRS	PMSWINC_EL0, R3                                  // ERROR "system register is not readable"
 	MRS	OSLAR_EL1, R3                                    // ERROR "system register is not readable"
+	VLD3R.P	24(R15), [V15.H4,V16.H4,V17.H4]                  // ERROR "invalid post-increment offset"
+	VBIT	V1.H4, V12.H4, V3.H4                             // ERROR "invalid arrangement"
+	VBSL	V1.D2, V12.D2, V3.D2                             // ERROR "invalid arrangement"
+	VUXTL	V30.D2, V30.H8                                   // ERROR "operand mismatch"
+	VUXTL2	V20.B8, V21.H8                                   // ERROR "operand mismatch"
+	VUXTL	V3.D2, V4.B8                                     // ERROR "operand mismatch"
+	VUZP1	V0.B8, V30.B8, V1.B16                            // ERROR "operand mismatch"
+	VUZP2	V0.Q1, V30.Q1, V1.Q1                             // ERROR "invalid arrangement"
+	VUSHLL	$0, V30.D2, V30.H8                               // ERROR "operand mismatch"
+	VUSHLL2	$0, V20.B8, V21.H8                               // ERROR "operand mismatch"
+	VUSHLL	$8, V30.B8, V30.H8                               // ERROR "shift amount out of range"
+	VUSHLL2	$32, V30.S4, V2.D2                               // ERROR "shift amount out of range"
+	VBIF	V0.B8, V1.B8, V2.B16                             // ERROR "operand mismatch"
+	VBIF	V0.D2, V1.D2, V2.D2                              // ERROR "invalid arrangement"
 	RET

src/cmd/cgo/doc.go

@@ -112,6 +112,13 @@ The default C and C++ compilers may be changed by the CC and CXX
 environment variables, respectively; those environment variables
 may include command line options.
 
+The cgo tool will always invoke the C compiler with the source file's
+directory in the include path; i.e. -I${SRCDIR} is always implied. This
+means that if a header file foo/bar.h exists both in the source
+directory and also in the system include directory (or some other place
+specified by a -I flag), then "#include <foo/bar.h>" will always find the
+local version in preference to any other version.
+
 The cgo tool is enabled by default for native builds on systems where
 it is expected to work. It is disabled by default when
 cross-compiling. You can control this by setting the CGO_ENABLED

src/cmd/cgo/gcc.go

@@ -369,7 +369,18 @@ func (p *Package) guessKinds(f *File) []*Name {
 	fmt.Fprintf(&b, "#line 1 \"completed\"\n"+
 		"int __cgo__1 = __cgo__2;\n")
 
-	stderr := p.gccErrors(b.Bytes())
+	// We need to parse the output from this gcc command, so ensure that it
+	// doesn't have any ANSI escape sequences in it. (TERM=dumb is
+	// insufficient; if the user specifies CGO_CFLAGS=-fdiagnostics-color,
+	// GCC will ignore TERM, and GCC can also be configured at compile-time
+	// to ignore TERM.)
+	stderr := p.gccErrors(b.Bytes(), "-fdiagnostics-color=never")
+	if strings.Contains(stderr, "unrecognized command line option") {
+		// We're using an old version of GCC that doesn't understand
+		// -fdiagnostics-color. Those versions can't print color anyway,
+		// so just rerun without that option.
+		stderr = p.gccErrors(b.Bytes())
+	}
 	if stderr == "" {
 		fatalf("%s produced no output\non input:\n%s", p.gccBaseCmd()[0], b.Bytes())
 	}
@@ -1970,22 +1981,25 @@ func (p *Package) gccDefines(stdin []byte) string {
 // gccErrors runs gcc over the C program stdin and returns
 // the errors that gcc prints. That is, this function expects
 // gcc to fail.
-func (p *Package) gccErrors(stdin []byte) string {
+func (p *Package) gccErrors(stdin []byte, extraArgs ...string) string {
 	// TODO(rsc): require failure
 	args := p.gccCmd()
 
 	// Optimization options can confuse the error messages; remove them.
-	nargs := make([]string, 0, len(args))
+	nargs := make([]string, 0, len(args)+len(extraArgs))
 	for _, arg := range args {
 		if !strings.HasPrefix(arg, "-O") {
 			nargs = append(nargs, arg)
 		}
 	}
 
-	// Force -O0 optimization but keep the trailing "-" at the end.
+	// Force -O0 optimization and append extra arguments, but keep the
-	nargs = append(nargs, "-O0")
+	// trailing "-" at the end.
-	nl := len(nargs)
+	li := len(nargs) - 1
-	nargs[nl-2], nargs[nl-1] = nargs[nl-1], nargs[nl-2]
+	last := nargs[li]
+	nargs[li] = "-O0"
+	nargs = append(nargs, extraArgs...)
+	nargs = append(nargs, last)
 
 	if *debugGcc {
 		fmt.Fprintf(os.Stderr, "$ %s <<EOF\n", strings.Join(nargs, " "))

src/cmd/compile/internal/amd64/ssa.go

@@ -319,8 +319,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 			// TODO(khr): issue only the -1 fixup code we need.
 			// For instance, if only the quotient is used, no point in zeroing the remainder.
 
-			j1.To.Val = n1
+			j1.To.SetTarget(n1)
-			j2.To.Val = s.Pc()
+			j2.To.SetTarget(s.Pc())
 		}
 
 	case ssa.OpAMD64HMULQ, ssa.OpAMD64HMULL, ssa.OpAMD64HMULQU, ssa.OpAMD64HMULLU:

src/cmd/compile/internal/arm64/ssa.go

@@ -816,7 +816,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		}
 		p := s.Prog(v.Op.Asm())
 		p.From.Type = obj.TYPE_REG // assembler encodes conditional bits in Reg
-		p.From.Reg = condBits[v.Aux.(ssa.Op)]
+		p.From.Reg = condBits[ssa.Op(v.AuxInt)]
 		p.Reg = v.Args[0].Reg()
 		p.SetFrom3(obj.Addr{Type: obj.TYPE_REG, Reg: r1})
 		p.To.Type = obj.TYPE_REG

src/cmd/compile/internal/gc/alg.go

@@ -429,8 +429,7 @@ func hashfor(t *types.Type) *Node {
 	}
 
 	n := newname(sym)
-	n.SetClass(PFUNC)
+	setNodeNameFunc(n)
-	n.Sym.SetFunc(true)
 	n.Type = functype(nil, []*Node{
 		anonfield(types.NewPtr(t)),
 		anonfield(types.Types[TUINTPTR]),
@@ -646,17 +645,11 @@ func geneq(t *types.Type) *obj.LSym {
 		// Build a list of conditions to satisfy.
 		// The conditions are a list-of-lists. Conditions are reorderable
 		// within each inner list. The outer lists must be evaluated in order.
-		// Even within each inner list, track their order so that we can preserve
+		var conds [][]*Node
-		// aspects of that order. (TODO: latter part needed?)
+		conds = append(conds, []*Node{})
-		type nodeIdx struct {
-			n   *Node
-			idx int
-		}
-		var conds [][]nodeIdx
-		conds = append(conds, []nodeIdx{})
 		and := func(n *Node) {
 			i := len(conds) - 1
-			conds[i] = append(conds[i], nodeIdx{n: n, idx: len(conds[i])})
+			conds[i] = append(conds[i], n)
 		}
 
 		// Walk the struct using memequal for runs of AMEM
@@ -674,7 +667,7 @@ func geneq(t *types.Type) *obj.LSym {
 			if !IsRegularMemory(f.Type) {
 				if EqCanPanic(f.Type) {
 					// Enforce ordering by starting a new set of reorderable conditions.
-					conds = append(conds, []nodeIdx{})
+					conds = append(conds, []*Node{})
 				}
 				p := nodSym(OXDOT, np, f.Sym)
 				q := nodSym(OXDOT, nq, f.Sym)
@@ -688,7 +681,7 @@ func geneq(t *types.Type) *obj.LSym {
 				}
 				if EqCanPanic(f.Type) {
 					// Also enforce ordering after something that can panic.
-					conds = append(conds, []nodeIdx{})
+					conds = append(conds, []*Node{})
 				}
 				i++
 				continue
@@ -713,14 +706,13 @@ func geneq(t *types.Type) *obj.LSym {
 
 		// Sort conditions to put runtime calls last.
 		// Preserve the rest of the ordering.
-		var flatConds []nodeIdx
+		var flatConds []*Node
 		for _, c := range conds {
+			isCall := func(n *Node) bool {
+				return n.Op == OCALL || n.Op == OCALLFUNC
+			}
 			sort.SliceStable(c, func(i, j int) bool {
-				x, y := c[i], c[j]
+				return !isCall(c[i]) && isCall(c[j])
-				if (x.n.Op != OCALL) == (y.n.Op != OCALL) {
-					return x.idx < y.idx
-				}
-				return x.n.Op != OCALL
 			})
 			flatConds = append(flatConds, c...)
 		}
@@ -729,9 +721,9 @@ func geneq(t *types.Type) *obj.LSym {
 		if len(flatConds) == 0 {
 			cond = nodbool(true)
 		} else {
-			cond = flatConds[0].n
+			cond = flatConds[0]
 			for _, c := range flatConds[1:] {
-				cond = nod(OANDAND, cond, c.n)
+				cond = nod(OANDAND, cond, c)
 			}
 		}
 

src/cmd/compile/internal/gc/closure.go

@@ -107,18 +107,7 @@ func typecheckclosure(clo *Node, top int) {
 	}
 
 	xfunc.Func.Nname.Sym = closurename(Curfn)
-	disableExport(xfunc.Func.Nname.Sym)
+	setNodeNameFunc(xfunc.Func.Nname)
-	if xfunc.Func.Nname.Sym.Def != nil {
-		// The only case we can reach here is when the outer function was redeclared.
-		// In that case, don't bother to redeclare the closure. Otherwise, we will get
-		// a spurious error message, see #17758. While we are here, double check that
-		// we already reported other error.
-		if nsavederrors+nerrors == 0 {
-			Fatalf("unexpected symbol collision %v", xfunc.Func.Nname.Sym)
-		}
-	} else {
-		declare(xfunc.Func.Nname, PFUNC)
-	}
 	xfunc = typecheck(xfunc, ctxStmt)
 
 	// Type check the body now, but only if we're inside a function.
@@ -473,7 +462,6 @@ func makepartialcall(fn *Node, t0 *types.Type, meth *types.Sym) *Node {
 	tfn.List.Set(structargs(t0.Params(), true))
 	tfn.Rlist.Set(structargs(t0.Results(), false))
 
-	disableExport(sym)
 	xfunc := dclfunc(sym, tfn)
 	xfunc.Func.SetDupok(true)
 	xfunc.Func.SetNeedctxt(true)

src/cmd/compile/internal/gc/dcl.go

@@ -90,7 +90,7 @@ func declare(n *Node, ctxt Class) {
 			lineno = n.Pos
 			Fatalf("automatic outside function")
 		}
-		if Curfn != nil {
+		if Curfn != nil && ctxt != PFUNC {
 			Curfn.Func.Dcl = append(Curfn.Func.Dcl, n)
 		}
 		if n.Op == OTYPE {
@@ -297,6 +297,16 @@ func oldname(s *types.Sym) *Node {
 	return n
 }
 
+// importName is like oldname, but it reports an error if sym is from another package and not exported.
+func importName(sym *types.Sym) *Node {
+	n := oldname(sym)
+	if !types.IsExported(sym.Name) && sym.Pkg != localpkg {
+		n.SetDiag(true)
+		yyerror("cannot refer to unexported name %s.%s", sym.Pkg.Name, sym.Name)
+	}
+	return n
+}
+
 // := declarations
 func colasname(n *Node) bool {
 	switch n.Op {
@@ -975,10 +985,14 @@ func makefuncsym(s *types.Sym) {
 	}
 }
 
-// disableExport prevents sym from being included in package export
+// setNodeNameFunc marks a node as a function.
-// data. To be effectual, it must be called before declare.
+func setNodeNameFunc(n *Node) {
-func disableExport(sym *types.Sym) {
+	if n.Op != ONAME || n.Class() != Pxxx {
-	sym.SetOnExportList(true)
+		Fatalf("expected ONAME/Pxxx node, got %v", n)
+	}
+
+	n.SetClass(PFUNC)
+	n.Sym.SetFunc(true)
 }
 
 func dclfunc(sym *types.Sym, tfn *Node) *Node {
@@ -990,7 +1004,7 @@ func dclfunc(sym *types.Sym, tfn *Node) *Node {
 	fn.Func.Nname = newfuncnamel(lineno, sym)
 	fn.Func.Nname.Name.Defn = fn
 	fn.Func.Nname.Name.Param.Ntype = tfn
-	declare(fn.Func.Nname, PFUNC)
+	setNodeNameFunc(fn.Func.Nname)
 	funchdr(fn)
 	fn.Func.Nname.Name.Param.Ntype = typecheck(fn.Func.Nname.Name.Param.Ntype, ctxType)
 	return fn

src/cmd/compile/internal/gc/esc.go

@@ -377,14 +377,14 @@ func (e *Escape) paramTag(fn *Node, narg int, f *types.Field) string {
 		// This really doesn't have much to do with escape analysis per se,
 		// but we are reusing the ability to annotate an individual function
 		// argument and pass those annotations along to importing code.
-		if f.Type.Etype == TUINTPTR {
+		if f.Type.IsUintptr() {
 			if Debug['m'] != 0 {
 				Warnl(f.Pos, "assuming %v is unsafe uintptr", name())
 			}
 			return unsafeUintptrTag
 		}
 
-		if !types.Haspointers(f.Type) { // don't bother tagging for scalars
+		if !f.Type.HasPointers() { // don't bother tagging for scalars
 			return ""
 		}
 
@@ -407,13 +407,13 @@ func (e *Escape) paramTag(fn *Node, narg int, f *types.Field) string {
 	}
 
 	if fn.Func.Pragma&UintptrEscapes != 0 {
-		if f.Type.Etype == TUINTPTR {
+		if f.Type.IsUintptr() {
 			if Debug['m'] != 0 {
 				Warnl(f.Pos, "marking %v as escaping uintptr", name())
 			}
 			return uintptrEscapesTag
 		}
-		if f.IsDDD() && f.Type.Elem().Etype == TUINTPTR {
+		if f.IsDDD() && f.Type.Elem().IsUintptr() {
 			// final argument is ...uintptr.
 			if Debug['m'] != 0 {
 				Warnl(f.Pos, "marking %v as escaping ...uintptr", name())
@@ -422,7 +422,7 @@ func (e *Escape) paramTag(fn *Node, narg int, f *types.Field) string {
 		}
 	}
 
-	if !types.Haspointers(f.Type) { // don't bother tagging for scalars
+	if !f.Type.HasPointers() { // don't bother tagging for scalars
 		return ""
 	}
 

src/cmd/compile/internal/gc/escape.go

@@ -326,7 +326,7 @@ func (e *Escape) stmt(n *Node) {
 			if typesw && n.Left.Left != nil {
 				cv := cas.Rlist.First()
 				k := e.dcl(cv) // type switch variables have no ODCL.
-				if types.Haspointers(cv.Type) {
+				if cv.Type.HasPointers() {
 					ks = append(ks, k.dotType(cv.Type, cas, "switch case"))
 				}
 			}
@@ -433,7 +433,7 @@ func (e *Escape) exprSkipInit(k EscHole, n *Node) {
 
 	if uintptrEscapesHack && n.Op == OCONVNOP && n.Left.Type.IsUnsafePtr() {
 		// nop
-	} else if k.derefs >= 0 && !types.Haspointers(n.Type) {
+	} else if k.derefs >= 0 && !n.Type.HasPointers() {
 		k = e.discardHole()
 	}
 
@@ -485,7 +485,7 @@ func (e *Escape) exprSkipInit(k EscHole, n *Node) {
 		e.discard(max)
 
 	case OCONV, OCONVNOP:
-		if checkPtr(e.curfn, 2) && n.Type.Etype == TUNSAFEPTR && n.Left.Type.IsPtr() {
+		if checkPtr(e.curfn, 2) && n.Type.IsUnsafePtr() && n.Left.Type.IsPtr() {
 			// When -d=checkptr=2 is enabled, treat
 			// conversions to unsafe.Pointer as an
 			// escaping operation. This allows better
@@ -493,7 +493,7 @@ func (e *Escape) exprSkipInit(k EscHole, n *Node) {
 			// easily detect object boundaries on the heap
 			// than the stack.
 			e.assignHeap(n.Left, "conversion to unsafe.Pointer", n)
-		} else if n.Type.Etype == TUNSAFEPTR && n.Left.Type.Etype == TUINTPTR {
+		} else if n.Type.IsUnsafePtr() && n.Left.Type.IsUintptr() {
 			e.unsafeValue(k, n.Left)
 		} else {
 			e.expr(k, n.Left)
@@ -625,7 +625,7 @@ func (e *Escape) unsafeValue(k EscHole, n *Node) {
 
 	switch n.Op {
 	case OCONV, OCONVNOP:
-		if n.Left.Type.Etype == TUNSAFEPTR {
+		if n.Left.Type.IsUnsafePtr() {
 			e.expr(k, n.Left)
 		} else {
 			e.discard(n.Left)
@@ -698,7 +698,7 @@ func (e *Escape) addr(n *Node) EscHole {
 		e.assignHeap(n.Right, "key of map put", n)
 	}
 
-	if !types.Haspointers(n.Type) {
+	if !n.Type.HasPointers() {
 		k = e.discardHole()
 	}
 
@@ -811,14 +811,14 @@ func (e *Escape) call(ks []EscHole, call, where *Node) {
 		// slice might be allocated, and all slice elements
 		// might flow to heap.
 		appendeeK := ks[0]
-		if types.Haspointers(args[0].Type.Elem()) {
+		if args[0].Type.Elem().HasPointers() {
 			appendeeK = e.teeHole(appendeeK, e.heapHole().deref(call, "appendee slice"))
 		}
 		argument(appendeeK, args[0])
 
 		if call.IsDDD() {
 			appendedK := e.discardHole()
-			if args[1].Type.IsSlice() && types.Haspointers(args[1].Type.Elem()) {
+			if args[1].Type.IsSlice() && args[1].Type.Elem().HasPointers() {
 				appendedK = e.heapHole().deref(call, "appended slice...")
 			}
 			argument(appendedK, args[1])
@@ -832,7 +832,7 @@ func (e *Escape) call(ks []EscHole, call, where *Node) {
 		argument(e.discardHole(), call.Left)
 
 		copiedK := e.discardHole()
-		if call.Right.Type.IsSlice() && types.Haspointers(call.Right.Type.Elem()) {
+		if call.Right.Type.IsSlice() && call.Right.Type.Elem().HasPointers() {
 			copiedK = e.heapHole().deref(call, "copied slice")
 		}
 		argument(copiedK, call.Right)
@@ -1029,6 +1029,9 @@ func (e *Escape) newLoc(n *Node, transient bool) *EscLocation {
 	if e.curfn == nil {
 		Fatalf("e.curfn isn't set")
 	}
+	if n != nil && n.Type != nil && n.Type.NotInHeap() {
+		yyerrorl(n.Pos, "%v is go:notinheap; stack allocation disallowed", n.Type)
+	}
 
 	n = canonicalNode(n)
 	loc := &EscLocation{

src/cmd/compile/internal/gc/fmt.go

@@ -1616,7 +1616,8 @@ func (n *Node) exprfmt(s fmt.State, prec int, mode fmtMode) {
 			}
 			n1.exprfmt(s, nprec, mode)
 		}
-
+	case ODDD:
+		mode.Fprintf(s, "...")
 	default:
 		mode.Fprintf(s, "<node %v>", n.Op)
 	}

src/cmd/compile/internal/gc/gsubr.go

@@ -32,7 +32,6 @@ package gc
 
 import (
 	"cmd/compile/internal/ssa"
-	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/objabi"
 	"cmd/internal/src"
@@ -316,7 +315,7 @@ func ggloblnod(nam *Node) {
 	if nam.Name.Readonly() {
 		flags = obj.RODATA
 	}
-	if nam.Type != nil && !types.Haspointers(nam.Type) {
+	if nam.Type != nil && !nam.Type.HasPointers() {
 		flags |= obj.NOPTR
 	}
 	Ctxt.Globl(s, nam.Type.Width, flags)
@@ -343,6 +342,6 @@ func Patch(p *obj.Prog, to *obj.Prog) {
 	if p.To.Type != obj.TYPE_BRANCH {
 		Fatalf("patch: not a branch")
 	}
-	p.To.Val = to
+	p.To.SetTarget(to)
 	p.To.Offset = to.Pc
 }

src/cmd/compile/internal/gc/init.go

@@ -45,7 +45,6 @@ func fninit(n []*Node) {
 	if len(nf) > 0 {
 		lineno = nf[0].Pos // prolog/epilog gets line number of first init stmt
 		initializers := lookup("init")
-		disableExport(initializers)
 		fn := dclfunc(initializers, nod(OTFUNC, nil, nil))
 		for _, dcl := range dummyInitFn.Func.Dcl {
 			dcl.Name.Curfn = fn

src/cmd/compile/internal/gc/noder.go

@@ -653,7 +653,7 @@ func (p *noder) expr(expr syntax.Expr) *Node {
 		obj := p.expr(expr.X)
 		if obj.Op == OPACK {
 			obj.Name.SetUsed(true)
-			return oldname(restrictlookup(expr.Sel.Value, obj.Name.Pkg))
+			return importName(obj.Name.Pkg.Lookup(expr.Sel.Value))
 		}
 		n := nodSym(OXDOT, obj, p.name(expr.Sel))
 		n.Pos = p.pos(expr) // lineno may have been changed by p.expr(expr.X)
@@ -857,7 +857,7 @@ func (p *noder) interfaceType(expr *syntax.InterfaceType) *Node {
 		p.setlineno(method)
 		var n *Node
 		if method.Name == nil {
-			n = p.nodSym(method, ODCLFIELD, oldname(p.packname(method.Type)), nil)
+			n = p.nodSym(method, ODCLFIELD, importName(p.packname(method.Type)), nil)
 		} else {
 			mname := p.name(method.Name)
 			sig := p.typeExpr(method.Type)
@@ -896,7 +896,7 @@ func (p *noder) packname(expr syntax.Expr) *types.Sym {
 			def.Name.SetUsed(true)
 			pkg = def.Name.Pkg
 		}
-		return restrictlookup(expr.Sel.Value, pkg)
+		return pkg.Lookup(expr.Sel.Value)
 	}
 	panic(fmt.Sprintf("unexpected packname: %#v", expr))
 }
@@ -911,7 +911,7 @@ func (p *noder) embedded(typ syntax.Expr) *Node {
 	}
 
 	sym := p.packname(typ)
-	n := p.nodSym(typ, ODCLFIELD, oldname(sym), lookup(sym.Name))
+	n := p.nodSym(typ, ODCLFIELD, importName(sym), lookup(sym.Name))
 	n.SetEmbedded(true)
 
 	if isStar {
@@ -1641,10 +1641,3 @@ func mkname(sym *types.Sym) *Node {
 	}
 	return n
 }
-
-func unparen(x *Node) *Node {
-	for x.Op == OPAREN {
-		x = x.Left
-	}
-	return x
-}

src/cmd/compile/internal/gc/order.go

@@ -502,6 +502,7 @@ func (o *Order) call(n *Node) {
 			x := o.copyExpr(arg.Left, arg.Left.Type, false)
 			x.Name.SetKeepalive(true)
 			arg.Left = x
+			n.SetNeedsWrapper(true)
 		}
 	}
 
@@ -927,7 +928,7 @@ func (o *Order) stmt(n *Node) {
 						n2.Ninit.Append(tmp2)
 					}
 
-					r.Left = o.newTemp(r.Right.Left.Type.Elem(), types.Haspointers(r.Right.Left.Type.Elem()))
+					r.Left = o.newTemp(r.Right.Left.Type.Elem(), r.Right.Left.Type.Elem().HasPointers())
 					tmp2 := nod(OAS, tmp1, r.Left)
 					tmp2 = typecheck(tmp2, ctxStmt)
 					n2.Ninit.Append(tmp2)
@@ -1406,7 +1407,7 @@ func (o *Order) as2(n *Node) {
 	left := []*Node{}
 	for ni, l := range n.List.Slice() {
 		if !l.isBlank() {
-			tmp := o.newTemp(l.Type, types.Haspointers(l.Type))
+			tmp := o.newTemp(l.Type, l.Type.HasPointers())
 			n.List.SetIndex(ni, tmp)
 			tmplist = append(tmplist, tmp)
 			left = append(left, l)
@@ -1428,7 +1429,7 @@ func (o *Order) okAs2(n *Node) {
 	var tmp1, tmp2 *Node
 	if !n.List.First().isBlank() {
 		typ := n.Right.Type
-		tmp1 = o.newTemp(typ, types.Haspointers(typ))
+		tmp1 = o.newTemp(typ, typ.HasPointers())
 	}
 
 	if !n.List.Second().isBlank() {

src/cmd/compile/internal/gc/pgen.go

@@ -80,8 +80,8 @@ func cmpstackvarlt(a, b *Node) bool {
 		return a.Name.Used()
 	}
 
-	ap := types.Haspointers(a.Type)
+	ap := a.Type.HasPointers()
-	bp := types.Haspointers(b.Type)
+	bp := b.Type.HasPointers()
 	if ap != bp {
 		return ap
 	}
@@ -176,7 +176,7 @@ func (s *ssafn) AllocFrame(f *ssa.Func) {
 		}
 		s.stksize += w
 		s.stksize = Rnd(s.stksize, int64(n.Type.Align))
-		if types.Haspointers(n.Type) {
+		if n.Type.HasPointers() {
 			s.stkptrsize = s.stksize
 			lastHasPtr = true
 		} else {
@@ -507,7 +507,7 @@ func createSimpleVar(fnsym *obj.LSym, n *Node) *dwarf.Var {
 		if Ctxt.FixedFrameSize() == 0 {
 			offs -= int64(Widthptr)
 		}
-		if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) || objabi.GOARCH == "arm64" {
+		if objabi.Framepointer_enabled || objabi.GOARCH == "arm64" {
 			// There is a word space for FP on ARM64 even if the frame pointer is disabled
 			offs -= int64(Widthptr)
 		}
@@ -703,7 +703,7 @@ func stackOffset(slot ssa.LocalSlot) int32 {
 		if Ctxt.FixedFrameSize() == 0 {
 			base -= int64(Widthptr)
 		}
-		if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) || objabi.GOARCH == "arm64" {
+		if objabi.Framepointer_enabled || objabi.GOARCH == "arm64" {
 			// There is a word space for FP on ARM64 even if the frame pointer is disabled
 			base -= int64(Widthptr)
 		}

src/cmd/compile/internal/gc/pgen_test.go

@@ -20,7 +20,7 @@ func typeWithoutPointers() *types.Type {
 
 func typeWithPointers() *types.Type {
 	t := types.New(TSTRUCT)
-	f := &types.Field{Type: types.New(TPTR)}
+	f := &types.Field{Type: types.NewPtr(types.New(TINT))}
 	t.SetFields([]*types.Field{f})
 	return t
 }
@@ -181,14 +181,6 @@ func TestStackvarSort(t *testing.T) {
 		nodeWithClass(Node{Type: &types.Type{}, Sym: &types.Sym{Name: "xyz"}}, PAUTO),
 		nodeWithClass(Node{Type: typeWithoutPointers(), Sym: &types.Sym{}}, PAUTO),
 	}
-	// haspointers updates Type.Haspointers as a side effect, so
-	// exercise this function on all inputs so that reflect.DeepEqual
-	// doesn't produce false positives.
-	for i := range want {
-		types.Haspointers(want[i].Type)
-		types.Haspointers(inp[i].Type)
-	}
-
 	sort.Sort(byStackVar(inp))
 	if !reflect.DeepEqual(want, inp) {
 		t.Error("sort failed")

src/cmd/compile/internal/gc/plive.go

@@ -259,7 +259,7 @@ func (v *varRegVec) AndNot(v1, v2 varRegVec) {
 // nor do we care about empty structs (handled by the pointer check),
 // nor do we care about the fake PAUTOHEAP variables.
 func livenessShouldTrack(n *Node) bool {
-	return n.Op == ONAME && (n.Class() == PAUTO || n.Class() == PPARAM || n.Class() == PPARAMOUT) && types.Haspointers(n.Type)
+	return n.Op == ONAME && (n.Class() == PAUTO || n.Class() == PPARAM || n.Class() == PPARAMOUT) && n.Type.HasPointers()
 }
 
 // getvariables returns the list of on-stack variables that we need to track
@@ -436,7 +436,7 @@ func (lv *Liveness) regEffects(v *ssa.Value) (uevar, kill liveRegMask) {
 		case ssa.LocalSlot:
 			return mask
 		case *ssa.Register:
-			if ptrOnly && !v.Type.HasHeapPointer() {
+			if ptrOnly && !v.Type.HasPointers() {
 				return mask
 			}
 			regs[0] = loc
@@ -451,7 +451,7 @@ func (lv *Liveness) regEffects(v *ssa.Value) (uevar, kill liveRegMask) {
 				if loc1 == nil {
 					continue
 				}
-				if ptrOnly && !v.Type.FieldType(i).HasHeapPointer() {
+				if ptrOnly && !v.Type.FieldType(i).HasPointers() {
 					continue
 				}
 				regs[nreg] = loc1.(*ssa.Register)
@@ -568,13 +568,13 @@ func onebitwalktype1(t *types.Type, off int64, bv bvec) {
 	if t.Align > 0 && off&int64(t.Align-1) != 0 {
 		Fatalf("onebitwalktype1: invalid initial alignment: type %v has alignment %d, but offset is %v", t, t.Align, off)
 	}
+	if !t.HasPointers() {
+		// Note: this case ensures that pointers to go:notinheap types
+		// are not considered pointers by garbage collection and stack copying.
+		return
+	}
 
 	switch t.Etype {
-	case TINT8, TUINT8, TINT16, TUINT16,
-		TINT32, TUINT32, TINT64, TUINT64,
-		TINT, TUINT, TUINTPTR, TBOOL,
-		TFLOAT32, TFLOAT64, TCOMPLEX64, TCOMPLEX128:
-
 	case TPTR, TUNSAFEPTR, TFUNC, TCHAN, TMAP:
 		if off&int64(Widthptr-1) != 0 {
 			Fatalf("onebitwalktype1: invalid alignment, %v", t)

src/cmd/compile/internal/gc/range.go

@@ -334,7 +334,7 @@ func walkrange(n *Node) *Node {
 
 		hv1 := temp(t.Elem())
 		hv1.SetTypecheck(1)
-		if types.Haspointers(t.Elem()) {
+		if t.Elem().HasPointers() {
 			init = append(init, nod(OAS, hv1, nil))
 		}
 		hb := temp(types.Types[TBOOL])
@@ -586,7 +586,7 @@ func arrayClear(n, v1, v2, a *Node) bool {
 	n.Nbody.Append(nod(OAS, hn, tmp))
 
 	var fn *Node
-	if a.Type.Elem().HasHeapPointer() {
+	if a.Type.Elem().HasPointers() {
 		// memclrHasPointers(hp, hn)
 		Curfn.Func.setWBPos(stmt.Pos)
 		fn = mkcall("memclrHasPointers", nil, nil, hp, hn)

src/cmd/compile/internal/gc/reflect.go

@@ -119,7 +119,7 @@ func bmap(t *types.Type) *types.Type {
 	// the type of the overflow field to uintptr in this case.
 	// See comment on hmap.overflow in runtime/map.go.
 	otyp := types.NewPtr(bucket)
-	if !types.Haspointers(elemtype) && !types.Haspointers(keytype) {
+	if !elemtype.HasPointers() && !keytype.HasPointers() {
 		otyp = types.Types[TUINTPTR]
 	}
 	overflow := makefield("overflow", otyp)
@@ -754,7 +754,7 @@ var kinds = []int{
 // typeptrdata returns the length in bytes of the prefix of t
 // containing pointer data. Anything after this offset is scalar data.
 func typeptrdata(t *types.Type) int64 {
-	if !types.Haspointers(t) {
+	if !t.HasPointers() {
 		return 0
 	}
 
@@ -788,7 +788,7 @@ func typeptrdata(t *types.Type) int64 {
 		// Find the last field that has pointers.
 		var lastPtrField *types.Field
 		for _, t1 := range t.Fields().Slice() {
-			if types.Haspointers(t1.Type) {
+			if t1.Type.HasPointers() {
 				lastPtrField = t1
 			}
 		}
@@ -1734,7 +1734,7 @@ func fillptrmask(t *types.Type, ptrmask []byte) {
 	for i := range ptrmask {
 		ptrmask[i] = 0
 	}
-	if !types.Haspointers(t) {
+	if !t.HasPointers() {
 		return
 	}
 
@@ -1803,7 +1803,7 @@ func (p *GCProg) end() {
 
 func (p *GCProg) emit(t *types.Type, offset int64) {
 	dowidth(t)
-	if !types.Haspointers(t) {
+	if !t.HasPointers() {
 		return
 	}
 	if t.Width == int64(Widthptr) {

src/cmd/compile/internal/gc/select.go

@@ -251,10 +251,8 @@ func walkselectcases(cases *Nodes) []*Node {
 	r = typecheck(r, ctxStmt)
 	init = append(init, r)
 
+	// No initialization for order; runtime.selectgo is responsible for that.
 	order := temp(types.NewArray(types.Types[TUINT16], 2*int64(ncas)))
-	r = nod(OAS, order, nil)
-	r = typecheck(r, ctxStmt)
-	init = append(init, r)
 
 	var pc0, pcs *Node
 	if flag_race {

src/cmd/compile/internal/gc/ssa.go

@@ -295,7 +295,10 @@ func (s *state) emitOpenDeferInfo() {
 // worker indicates which of the backend workers is doing the processing.
 func buildssa(fn *Node, worker int) *ssa.Func {
 	name := fn.funcname()
-	printssa := name == ssaDump
+	printssa := false
+	if ssaDump != "" { // match either a simple name e.g. "(*Reader).Reset", or a package.name e.g. "compress/gzip.(*Reader).Reset"
+		printssa = name == ssaDump || myimportpath+"."+name == ssaDump
+	}
 	var astBuf *bytes.Buffer
 	if printssa {
 		astBuf = &bytes.Buffer{}
@@ -329,8 +332,8 @@ func buildssa(fn *Node, worker int) *ssa.Func {
 	s.f.Config = ssaConfig
 	s.f.Cache = &ssaCaches[worker]
 	s.f.Cache.Reset()
-	s.f.DebugTest = s.f.DebugHashMatch("GOSSAHASH", name)
 	s.f.Name = name
+	s.f.DebugTest = s.f.DebugHashMatch("GOSSAHASH")
 	s.f.PrintOrHtmlSSA = printssa
 	if fn.Func.Pragma&Nosplit != 0 {
 		s.f.NoSplit = true
@@ -2110,7 +2113,7 @@ func (s *state) expr(n *Node) *ssa.Value {
 		}
 
 		// unsafe.Pointer <--> *T
-		if to.Etype == TUNSAFEPTR && from.IsPtrShaped() || from.Etype == TUNSAFEPTR && to.IsPtrShaped() {
+		if to.IsUnsafePtr() && from.IsPtrShaped() || from.IsUnsafePtr() && to.IsPtrShaped() {
 			return v
 		}
 
@@ -4207,7 +4210,7 @@ func (s *state) openDeferSave(n *Node, t *types.Type, val *ssa.Value) *ssa.Value
 		s.vars[&memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, argTemp, s.mem(), false)
 		addrArgTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(argTemp.Type), argTemp, s.sp, s.mem(), false)
 	}
-	if types.Haspointers(t) {
+	if t.HasPointers() {
 		// Since we may use this argTemp during exit depending on the
 		// deferBits, we must define it unconditionally on entry.
 		// Therefore, we must make sure it is zeroed out in the entry
@@ -4309,12 +4312,12 @@ func (s *state) openDeferExit() {
 			s.vars[&memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.closureNode, s.mem(), false)
 		}
 		if r.rcvrNode != nil {
-			if types.Haspointers(r.rcvrNode.Type) {
+			if r.rcvrNode.Type.HasPointers() {
 				s.vars[&memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.rcvrNode, s.mem(), false)
 			}
 		}
 		for _, argNode := range r.argNodes {
-			if types.Haspointers(argNode.Type) {
+			if argNode.Type.HasPointers() {
 				s.vars[&memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, argNode, s.mem(), false)
 			}
 		}
@@ -4954,7 +4957,7 @@ func (s *state) rtcall(fn *obj.LSym, returns bool, results []*types.Type, args .
 func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask, leftIsStmt bool) {
 	s.instrument(t, left, true)
 
-	if skip == 0 && (!types.Haspointers(t) || ssa.IsStackAddr(left)) {
+	if skip == 0 && (!t.HasPointers() || ssa.IsStackAddr(left)) {
 		// Known to not have write barrier. Store the whole type.
 		s.vars[&memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, left, right, s.mem(), leftIsStmt)
 		return
@@ -4966,7 +4969,7 @@ func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask,
 	// TODO: if the writebarrier pass knows how to reorder stores,
 	// we can do a single store here as long as skip==0.
 	s.storeTypeScalars(t, left, right, skip)
-	if skip&skipPtr == 0 && types.Haspointers(t) {
+	if skip&skipPtr == 0 && t.HasPointers() {
 		s.storeTypePtrs(t, left, right)
 	}
 }
@@ -5038,7 +5041,7 @@ func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) {
 		n := t.NumFields()
 		for i := 0; i < n; i++ {
 			ft := t.FieldType(i)
-			if !types.Haspointers(ft) {
+			if !ft.HasPointers() {
 				continue
 			}
 			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
@@ -6179,7 +6182,7 @@ func genssa(f *ssa.Func, pp *Progs) {
 
 	// Resolve branches, and relax DefaultStmt into NotStmt
 	for _, br := range s.Branches {
-		br.P.To.Val = s.bstart[br.B.ID]
+		br.P.To.SetTarget(s.bstart[br.B.ID])
 		if br.P.Pos.IsStmt() != src.PosIsStmt {
 			br.P.Pos = br.P.Pos.WithNotStmt()
 		} else if v0 := br.B.FirstPossibleStmtValue(); v0 != nil && v0.Pos.Line() == br.P.Pos.Line() && v0.Pos.IsStmt() == src.PosIsStmt {
@@ -6863,6 +6866,10 @@ func (e *ssafn) SetWBPos(pos src.XPos) {
 	e.curfn.Func.setWBPos(pos)
 }
 
+func (e *ssafn) MyImportPath() string {
+	return myimportpath
+}
+
 func (n *Node) Typ() *types.Type {
 	return n.Type
 }

src/cmd/compile/internal/gc/subr.go

@@ -271,13 +271,6 @@ func autolabel(prefix string) *types.Sym {
 	return lookupN(prefix, int(n))
 }
 
-func restrictlookup(name string, pkg *types.Pkg) *types.Sym {
-	if !types.IsExported(name) && pkg != localpkg {
-		yyerror("cannot refer to unexported name %s.%s", pkg.Name, name)
-	}
-	return pkg.Lookup(name)
-}
-
 // find all the exported symbols in package opkg
 // and make them available in the current package
 func importdot(opkg *types.Pkg, pack *Node) {
@@ -788,12 +781,12 @@ func convertop(srcConstant bool, src, dst *types.Type, why *string) Op {
 	}
 
 	// 8. src is a pointer or uintptr and dst is unsafe.Pointer.
-	if (src.IsPtr() || src.Etype == TUINTPTR) && dst.Etype == TUNSAFEPTR {
+	if (src.IsPtr() || src.IsUintptr()) && dst.IsUnsafePtr() {
 		return OCONVNOP
 	}
 
 	// 9. src is unsafe.Pointer and dst is a pointer or uintptr.
-	if src.Etype == TUNSAFEPTR && (dst.IsPtr() || dst.Etype == TUINTPTR) {
+	if src.IsUnsafePtr() && (dst.IsPtr() || dst.IsUintptr()) {
 		return OCONVNOP
 	}
 
@@ -1550,7 +1543,6 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 	tfn.List.Set(structargs(method.Type.Params(), true))
 	tfn.Rlist.Set(structargs(method.Type.Results(), false))
 
-	disableExport(newnam)
 	fn := dclfunc(newnam, tfn)
 	fn.Func.SetDupok(true)
 
@@ -1638,8 +1630,7 @@ func hashmem(t *types.Type) *Node {
 	sym := Runtimepkg.Lookup("memhash")
 
 	n := newname(sym)
-	n.SetClass(PFUNC)
+	setNodeNameFunc(n)
-	n.Sym.SetFunc(true)
 	n.Type = functype(nil, []*Node{
 		anonfield(types.NewPtr(t)),
 		anonfield(types.Types[TUINTPTR]),

src/cmd/compile/internal/gc/syntax.go

@@ -141,19 +141,20 @@ const (
 	nodeInitorder, _                   // tracks state during init1; two bits
 	_, _                               // second nodeInitorder bit
 	_, nodeHasBreak
-	_, nodeNoInline  // used internally by inliner to indicate that a function call should not be inlined; set for OCALLFUNC and OCALLMETH only
+	_, nodeNoInline     // used internally by inliner to indicate that a function call should not be inlined; set for OCALLFUNC and OCALLMETH only
-	_, nodeImplicit  // implicit OADDR or ODEREF; ++/-- statement represented as OASOP; or ANDNOT lowered to OAND
+	_, nodeImplicit     // implicit OADDR or ODEREF; ++/-- statement represented as OASOP; or ANDNOT lowered to OAND
-	_, nodeIsDDD     // is the argument variadic
+	_, nodeIsDDD        // is the argument variadic
-	_, nodeDiag      // already printed error about this
+	_, nodeDiag         // already printed error about this
-	_, nodeColas     // OAS resulting from :=
+	_, nodeColas        // OAS resulting from :=
-	_, nodeNonNil    // guaranteed to be non-nil
+	_, nodeNonNil       // guaranteed to be non-nil
-	_, nodeTransient // storage can be reused immediately after this statement
+	_, nodeTransient    // storage can be reused immediately after this statement
-	_, nodeBounded   // bounds check unnecessary
+	_, nodeBounded      // bounds check unnecessary
-	_, nodeHasCall   // expression contains a function call
+	_, nodeHasCall      // expression contains a function call
-	_, nodeLikely    // if statement condition likely
+	_, nodeLikely       // if statement condition likely
-	_, nodeHasVal    // node.E contains a Val
+	_, nodeHasVal       // node.E contains a Val
-	_, nodeHasOpt    // node.E contains an Opt
+	_, nodeHasOpt       // node.E contains an Opt
-	_, nodeEmbedded  // ODCLFIELD embedded type
+	_, nodeEmbedded     // ODCLFIELD embedded type
+	_, nodeNeedsWrapper // OCALLxxx node that needs to be wrapped
 )
 
 func (n *Node) Class() Class     { return Class(n.flags.get3(nodeClass)) }
@@ -286,6 +287,20 @@ func (n *Node) SetIota(x int64) {
 	n.Xoffset = x
 }
 
+func (n *Node) NeedsWrapper() bool {
+	return n.flags&nodeNeedsWrapper != 0
+}
+
+// SetNeedsWrapper indicates that OCALLxxx node needs to be wrapped by a closure.
+func (n *Node) SetNeedsWrapper(b bool) {
+	switch n.Op {
+	case OCALLFUNC, OCALLMETH, OCALLINTER:
+	default:
+		Fatalf("Node.SetNeedsWrapper %v", n.Op)
+	}
+	n.flags.set(nodeNeedsWrapper, b)
+}
+
 // mayBeShared reports whether n may occur in multiple places in the AST.
 // Extra care must be taken when mutating such a node.
 func (n *Node) mayBeShared() bool {

src/cmd/compile/internal/gc/walk.go

@@ -232,7 +232,11 @@ func walkstmt(n *Node) *Node {
 			n.Left = copyany(n.Left, &n.Ninit, true)
 
 		default:
-			n.Left = walkexpr(n.Left, &n.Ninit)
+			if n.Left.NeedsWrapper() {
+				n.Left = wrapCall(n.Left, &n.Ninit)
+			} else {
+				n.Left = walkexpr(n.Left, &n.Ninit)
+			}
 		}
 
 	case OFOR, OFORUNTIL:
@@ -381,9 +385,9 @@ func convFuncName(from, to *types.Type) (fnname string, needsaddr bool) {
 		switch {
 		case from.Size() == 2 && from.Align == 2:
 			return "convT16", false
-		case from.Size() == 4 && from.Align == 4 && !types.Haspointers(from):
+		case from.Size() == 4 && from.Align == 4 && !from.HasPointers():
 			return "convT32", false
-		case from.Size() == 8 && from.Align == types.Types[TUINT64].Align && !types.Haspointers(from):
+		case from.Size() == 8 && from.Align == types.Types[TUINT64].Align && !from.HasPointers():
 			return "convT64", false
 		}
 		if sc := from.SoleComponent(); sc != nil {
@@ -397,12 +401,12 @@ func convFuncName(from, to *types.Type) (fnname string, needsaddr bool) {
 
 		switch tkind {
 		case 'E':
-			if !types.Haspointers(from) {
+			if !from.HasPointers() {
 				return "convT2Enoptr", true
 			}
 			return "convT2E", true
 		case 'I':
-			if !types.Haspointers(from) {
+			if !from.HasPointers() {
 				return "convT2Inoptr", true
 			}
 			return "convT2I", true
@@ -954,11 +958,11 @@ opswitch:
 	case OCONV, OCONVNOP:
 		n.Left = walkexpr(n.Left, init)
 		if n.Op == OCONVNOP && checkPtr(Curfn, 1) {
-			if n.Type.IsPtr() && n.Left.Type.Etype == TUNSAFEPTR { // unsafe.Pointer to *T
+			if n.Type.IsPtr() && n.Left.Type.IsUnsafePtr() { // unsafe.Pointer to *T
 				n = walkCheckPtrAlignment(n, init, nil)
 				break
 			}
-			if n.Type.Etype == TUNSAFEPTR && n.Left.Type.Etype == TUINTPTR { // uintptr to unsafe.Pointer
+			if n.Type.IsUnsafePtr() && n.Left.Type.IsUintptr() { // uintptr to unsafe.Pointer
 				n = walkCheckPtrArithmetic(n, init)
 				break
 			}
@@ -1123,7 +1127,7 @@ opswitch:
 		n.List.SetSecond(walkexpr(n.List.Second(), init))
 
 	case OSLICE, OSLICEARR, OSLICESTR, OSLICE3, OSLICE3ARR:
-		checkSlice := checkPtr(Curfn, 1) && n.Op == OSLICE3ARR && n.Left.Op == OCONVNOP && n.Left.Left.Type.Etype == TUNSAFEPTR
+		checkSlice := checkPtr(Curfn, 1) && n.Op == OSLICE3ARR && n.Left.Op == OCONVNOP && n.Left.Left.Type.IsUnsafePtr()
 		if checkSlice {
 			n.Left.Left = walkexpr(n.Left.Left, init)
 		} else {
@@ -1156,6 +1160,9 @@ opswitch:
 		}
 
 	case ONEW:
+		if n.Type.Elem().NotInHeap() {
+			yyerror("%v is go:notinheap; heap allocation disallowed", n.Type.Elem())
+		}
 		if n.Esc == EscNone {
 			if n.Type.Elem().Width >= maxImplicitStackVarSize {
 				Fatalf("large ONEW with EscNone: %v", n)
@@ -1324,6 +1331,9 @@ opswitch:
 			l = r
 		}
 		t := n.Type
+		if t.Elem().NotInHeap() {
+			yyerror("%v is go:notinheap; heap allocation disallowed", t.Elem())
+		}
 		if n.Esc == EscNone {
 			if !isSmallMakeSlice(n) {
 				Fatalf("non-small OMAKESLICE with EscNone: %v", n)
@@ -1365,10 +1375,6 @@ opswitch:
 			// When len and cap can fit into int, use makeslice instead of
 			// makeslice64, which is faster and shorter on 32 bit platforms.
 
-			if t.Elem().NotInHeap() {
-				yyerror("%v is go:notinheap; heap allocation disallowed", t.Elem())
-			}
-
 			len, cap := l, r
 
 			fnname := "makeslice64"
@@ -1403,14 +1409,14 @@ opswitch:
 
 		t := n.Type
 		if t.Elem().NotInHeap() {
-			Fatalf("%v is go:notinheap; heap allocation disallowed", t.Elem())
+			yyerror("%v is go:notinheap; heap allocation disallowed", t.Elem())
 		}
 
 		length := conv(n.Left, types.Types[TINT])
 		copylen := nod(OLEN, n.Right, nil)
 		copyptr := nod(OSPTR, n.Right, nil)
 
-		if !types.Haspointers(t.Elem()) && n.Bounded() {
+		if !t.Elem().HasPointers() && n.Bounded() {
 			// When len(to)==len(from) and elements have no pointers:
 			// replace make+copy with runtime.mallocgc+runtime.memmove.
 
@@ -2012,9 +2018,6 @@ func walkprint(nn *Node, init *Nodes) *Node {
 }
 
 func callnew(t *types.Type) *Node {
-	if t.NotInHeap() {
-		yyerror("%v is go:notinheap; heap allocation disallowed", t)
-	}
 	dowidth(t)
 	n := nod(ONEWOBJ, typename(t), nil)
 	n.Type = types.NewPtr(t)
@@ -2589,7 +2592,7 @@ func mapfast(t *types.Type) int {
 	}
 	switch algtype(t.Key()) {
 	case AMEM32:
-		if !t.Key().HasHeapPointer() {
+		if !t.Key().HasPointers() {
 			return mapfast32
 		}
 		if Widthptr == 4 {
@@ -2597,7 +2600,7 @@ func mapfast(t *types.Type) int {
 		}
 		Fatalf("small pointer %v", t.Key())
 	case AMEM64:
-		if !t.Key().HasHeapPointer() {
+		if !t.Key().HasPointers() {
 			return mapfast64
 		}
 		if Widthptr == 8 {
@@ -2744,7 +2747,7 @@ func appendslice(n *Node, init *Nodes) *Node {
 	nodes.Append(nod(OAS, s, nt))
 
 	var ncopy *Node
-	if elemtype.HasHeapPointer() {
+	if elemtype.HasPointers() {
 		// copy(s[len(l1):], l2)
 		nptr1 := nod(OSLICE, s, nil)
 		nptr1.Type = s.Type
@@ -2865,7 +2868,7 @@ func isAppendOfMake(n *Node) bool {
 //     s = s[:n]
 //     lptr := &l1[0]
 //     sptr := &s[0]
-//     if lptr == sptr || !hasPointers(T) {
+//     if lptr == sptr || !T.HasPointers() {
 //       // growslice did not clear the whole underlying array (or did not get called)
 //       hp := &s[len(l1)]
 //       hn := l2 * sizeof(T)
@@ -2946,7 +2949,7 @@ func extendslice(n *Node, init *Nodes) *Node {
 	hn = conv(hn, types.Types[TUINTPTR])
 
 	clrname := "memclrNoHeapPointers"
-	hasPointers := types.Haspointers(elemtype)
+	hasPointers := elemtype.HasPointers()
 	if hasPointers {
 		clrname = "memclrHasPointers"
 		Curfn.Func.setWBPos(n.Pos)
@@ -3082,7 +3085,7 @@ func walkappend(n *Node, init *Nodes, dst *Node) *Node {
 // Also works if b is a string.
 //
 func copyany(n *Node, init *Nodes, runtimecall bool) *Node {
-	if n.Left.Type.Elem().HasHeapPointer() {
+	if n.Left.Type.Elem().HasPointers() {
 		Curfn.Func.setWBPos(n.Pos)
 		fn := writebarrierfn("typedslicecopy", n.Left.Type.Elem(), n.Right.Type.Elem())
 		n.Left = cheapexpr(n.Left, init)
@@ -3167,8 +3170,7 @@ func eqfor(t *types.Type) (n *Node, needsize bool) {
 	case ASPECIAL:
 		sym := typesymprefix(".eq", t)
 		n := newname(sym)
-		n.SetClass(PFUNC)
+		setNodeNameFunc(n)
-		n.Sym.SetFunc(true)
 		n.Type = functype(nil, []*Node{
 			anonfield(types.NewPtr(t)),
 			anonfield(types.NewPtr(t)),
@@ -3859,6 +3861,14 @@ func candiscard(n *Node) bool {
 //		builtin(a1, a2, a3)
 //	}(x, y, z)
 // for print, println, and delete.
+//
+// Rewrite
+//	go f(x, y, uintptr(unsafe.Pointer(z)))
+// into
+//	go func(a1, a2, a3) {
+//		builtin(a1, a2, uintptr(a3))
+//	}(x, y, unsafe.Pointer(z))
+// for function contains unsafe-uintptr arguments.
 
 var wrapCall_prgen int
 
@@ -3870,9 +3880,17 @@ func wrapCall(n *Node, init *Nodes) *Node {
 		init.AppendNodes(&n.Ninit)
 	}
 
+	isBuiltinCall := n.Op != OCALLFUNC && n.Op != OCALLMETH && n.Op != OCALLINTER
+	// origArgs keeps track of what argument is uintptr-unsafe/unsafe-uintptr conversion.
+	origArgs := make([]*Node, n.List.Len())
 	t := nod(OTFUNC, nil, nil)
 	for i, arg := range n.List.Slice() {
 		s := lookupN("a", i)
+		if !isBuiltinCall && arg.Op == OCONVNOP && arg.Type.IsUintptr() && arg.Left.Type.IsUnsafePtr() {
+			origArgs[i] = arg
+			arg = arg.Left
+			n.List.SetIndex(i, arg)
+		}
 		t.List.Append(symfield(s, arg.Type))
 	}
 
@@ -3880,10 +3898,22 @@ func wrapCall(n *Node, init *Nodes) *Node {
 	sym := lookupN("wrap·", wrapCall_prgen)
 	fn := dclfunc(sym, t)
 
-	a := nod(n.Op, nil, nil)
+	args := paramNnames(t.Type)
-	a.List.Set(paramNnames(t.Type))
+	for i, origArg := range origArgs {
-	a = typecheck(a, ctxStmt)
+		if origArg == nil {
-	fn.Nbody.Set1(a)
+			continue
+		}
+		arg := nod(origArg.Op, args[i], nil)
+		arg.Type = origArg.Type
+		args[i] = arg
+	}
+	call := nod(n.Op, nil, nil)
+	if !isBuiltinCall {
+		call.Op = OCALL
+		call.Left = n.Left
+	}
+	call.List.Set(args)
+	fn.Nbody.Set1(call)
 
 	funcbody()
 
@@ -3891,12 +3921,12 @@ func wrapCall(n *Node, init *Nodes) *Node {
 	typecheckslice(fn.Nbody.Slice(), ctxStmt)
 	xtop = append(xtop, fn)
 
-	a = nod(OCALL, nil, nil)
+	call = nod(OCALL, nil, nil)
-	a.Left = fn.Func.Nname
+	call.Left = fn.Func.Nname
-	a.List.Set(n.List.Slice())
+	call.List.Set(n.List.Slice())
-	a = typecheck(a, ctxStmt)
+	call = typecheck(call, ctxStmt)
-	a = walkexpr(a, init)
+	call = walkexpr(call, init)
-	return a
+	return call
 }
 
 // substArgTypes substitutes the given list of types for
@@ -4011,7 +4041,7 @@ func walkCheckPtrArithmetic(n *Node, init *Nodes) *Node {
 				walk(n.Left)
 			}
 		case OCONVNOP:
-			if n.Left.Type.Etype == TUNSAFEPTR {
+			if n.Left.Type.IsUnsafePtr() {
 				n.Left = cheapexpr(n.Left, init)
 				originals = append(originals, convnop(n.Left, types.Types[TUNSAFEPTR]))
 			}

src/cmd/compile/internal/ppc64/ssa.go

@@ -629,23 +629,6 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = r
 
-	case ssa.OpPPC64MaskIfNotCarry:
-		r := v.Reg()
-		p := s.Prog(v.Op.Asm())
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = ppc64.REGZERO
-		p.To.Type = obj.TYPE_REG
-		p.To.Reg = r
-
-	case ssa.OpPPC64ADDconstForCarry:
-		r1 := v.Args[0].Reg()
-		p := s.Prog(v.Op.Asm())
-		p.Reg = r1
-		p.From.Type = obj.TYPE_CONST
-		p.From.Offset = v.AuxInt
-		p.To.Type = obj.TYPE_REG
-		p.To.Reg = ppc64.REGTMP // Ignored; this is for the carry effect.
-
 	case ssa.OpPPC64NEG, ssa.OpPPC64FNEG, ssa.OpPPC64FSQRT, ssa.OpPPC64FSQRTS, ssa.OpPPC64FFLOOR, ssa.OpPPC64FTRUNC, ssa.OpPPC64FCEIL,
 		ssa.OpPPC64FCTIDZ, ssa.OpPPC64FCTIWZ, ssa.OpPPC64FCFID, ssa.OpPPC64FCFIDS, ssa.OpPPC64FRSP, ssa.OpPPC64CNTLZD, ssa.OpPPC64CNTLZW,
 		ssa.OpPPC64POPCNTD, ssa.OpPPC64POPCNTW, ssa.OpPPC64POPCNTB, ssa.OpPPC64MFVSRD, ssa.OpPPC64MTVSRD, ssa.OpPPC64FABS, ssa.OpPPC64FNABS,
@@ -666,6 +649,14 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
 
+	case ssa.OpPPC64SUBFCconst:
+		p := s.Prog(v.Op.Asm())
+		p.SetFrom3(obj.Addr{Type: obj.TYPE_CONST, Offset: v.AuxInt})
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = v.Args[0].Reg()
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = v.Reg()
+
 	case ssa.OpPPC64ANDCCconst:
 		p := s.Prog(v.Op.Asm())
 		p.Reg = v.Args[0].Reg()
@@ -1802,7 +1793,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		v.Fatalf("Pseudo-op should not make it to codegen: %s ###\n", v.LongString())
 	case ssa.OpPPC64InvertFlags:
 		v.Fatalf("InvertFlags should never make it to codegen %v", v.LongString())
-	case ssa.OpPPC64FlagEQ, ssa.OpPPC64FlagLT, ssa.OpPPC64FlagGT, ssa.OpPPC64FlagCarrySet, ssa.OpPPC64FlagCarryClear:
+	case ssa.OpPPC64FlagEQ, ssa.OpPPC64FlagLT, ssa.OpPPC64FlagGT:
 		v.Fatalf("Flag* ops should never make it to codegen %v", v.LongString())
 	case ssa.OpClobber:
 		// TODO: implement for clobberdead experiment. Nop is ok for now.

src/cmd/compile/internal/s390x/ssa.go

@@ -338,8 +338,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 				n.To.Reg = dividend
 			}
 
-			j.To.Val = n
+			j.To.SetTarget(n)
-			j2.To.Val = s.Pc()
+			j2.To.SetTarget(s.Pc())
 		}
 	case ssa.OpS390XADDconst, ssa.OpS390XADDWconst:
 		opregregimm(s, v.Op.Asm(), v.Reg(), v.Args[0].Reg(), v.AuxInt)

src/cmd/compile/internal/ssa/addressingmodes.go

@@ -7,12 +7,14 @@ package ssa
 // addressingModes combines address calculations into memory operations
 // that can perform complicated addressing modes.
 func addressingModes(f *Func) {
+	isInImmediateRange := is32Bit
 	switch f.Config.arch {
 	default:
 		// Most architectures can't do this.
 		return
 	case "amd64", "386":
-		// TODO: s390x?
+	case "s390x":
+		isInImmediateRange = is20Bit
 	}
 
 	var tmp []*Value
@@ -40,7 +42,7 @@ func addressingModes(f *Func) {
 			switch [2]auxType{opcodeTable[v.Op].auxType, opcodeTable[p.Op].auxType} {
 			case [2]auxType{auxSymOff, auxInt32}:
 				// TODO: introduce auxSymOff32
-				if !is32Bit(v.AuxInt + p.AuxInt) {
+				if !isInImmediateRange(v.AuxInt + p.AuxInt) {
 					continue
 				}
 				v.AuxInt += p.AuxInt
@@ -48,7 +50,7 @@ func addressingModes(f *Func) {
 				if v.Aux != nil && p.Aux != nil {
 					continue
 				}
-				if !is32Bit(v.AuxInt + p.AuxInt) {
+				if !isInImmediateRange(v.AuxInt + p.AuxInt) {
 					continue
 				}
 				if p.Aux != nil {
@@ -398,4 +400,61 @@ var combine = map[[2]Op]Op{
 	[2]Op{Op386ANDLconstmodify, Op386LEAL4}: Op386ANDLconstmodifyidx4,
 	[2]Op{Op386ORLconstmodify, Op386LEAL4}:  Op386ORLconstmodifyidx4,
 	[2]Op{Op386XORLconstmodify, Op386LEAL4}: Op386XORLconstmodifyidx4,
+
+	// s390x
+	[2]Op{OpS390XMOVDload, OpS390XADD}: OpS390XMOVDloadidx,
+	[2]Op{OpS390XMOVWload, OpS390XADD}: OpS390XMOVWloadidx,
+	[2]Op{OpS390XMOVHload, OpS390XADD}: OpS390XMOVHloadidx,
+	[2]Op{OpS390XMOVBload, OpS390XADD}: OpS390XMOVBloadidx,
+
+	[2]Op{OpS390XMOVWZload, OpS390XADD}: OpS390XMOVWZloadidx,
+	[2]Op{OpS390XMOVHZload, OpS390XADD}: OpS390XMOVHZloadidx,
+	[2]Op{OpS390XMOVBZload, OpS390XADD}: OpS390XMOVBZloadidx,
+
+	[2]Op{OpS390XMOVDBRload, OpS390XADD}: OpS390XMOVDBRloadidx,
+	[2]Op{OpS390XMOVWBRload, OpS390XADD}: OpS390XMOVWBRloadidx,
+	[2]Op{OpS390XMOVHBRload, OpS390XADD}: OpS390XMOVHBRloadidx,
+
+	[2]Op{OpS390XFMOVDload, OpS390XADD}: OpS390XFMOVDloadidx,
+	[2]Op{OpS390XFMOVSload, OpS390XADD}: OpS390XFMOVSloadidx,
+
+	[2]Op{OpS390XMOVDstore, OpS390XADD}: OpS390XMOVDstoreidx,
+	[2]Op{OpS390XMOVWstore, OpS390XADD}: OpS390XMOVWstoreidx,
+	[2]Op{OpS390XMOVHstore, OpS390XADD}: OpS390XMOVHstoreidx,
+	[2]Op{OpS390XMOVBstore, OpS390XADD}: OpS390XMOVBstoreidx,
+
+	[2]Op{OpS390XMOVDBRstore, OpS390XADD}: OpS390XMOVDBRstoreidx,
+	[2]Op{OpS390XMOVWBRstore, OpS390XADD}: OpS390XMOVWBRstoreidx,
+	[2]Op{OpS390XMOVHBRstore, OpS390XADD}: OpS390XMOVHBRstoreidx,
+
+	[2]Op{OpS390XFMOVDstore, OpS390XADD}: OpS390XFMOVDstoreidx,
+	[2]Op{OpS390XFMOVSstore, OpS390XADD}: OpS390XFMOVSstoreidx,
+
+	[2]Op{OpS390XMOVDload, OpS390XMOVDaddridx}: OpS390XMOVDloadidx,
+	[2]Op{OpS390XMOVWload, OpS390XMOVDaddridx}: OpS390XMOVWloadidx,
+	[2]Op{OpS390XMOVHload, OpS390XMOVDaddridx}: OpS390XMOVHloadidx,
+	[2]Op{OpS390XMOVBload, OpS390XMOVDaddridx}: OpS390XMOVBloadidx,
+
+	[2]Op{OpS390XMOVWZload, OpS390XMOVDaddridx}: OpS390XMOVWZloadidx,
+	[2]Op{OpS390XMOVHZload, OpS390XMOVDaddridx}: OpS390XMOVHZloadidx,
+	[2]Op{OpS390XMOVBZload, OpS390XMOVDaddridx}: OpS390XMOVBZloadidx,
+
+	[2]Op{OpS390XMOVDBRload, OpS390XMOVDaddridx}: OpS390XMOVDBRloadidx,
+	[2]Op{OpS390XMOVWBRload, OpS390XMOVDaddridx}: OpS390XMOVWBRloadidx,
+	[2]Op{OpS390XMOVHBRload, OpS390XMOVDaddridx}: OpS390XMOVHBRloadidx,
+
+	[2]Op{OpS390XFMOVDload, OpS390XMOVDaddridx}: OpS390XFMOVDloadidx,
+	[2]Op{OpS390XFMOVSload, OpS390XMOVDaddridx}: OpS390XFMOVSloadidx,
+
+	[2]Op{OpS390XMOVDstore, OpS390XMOVDaddridx}: OpS390XMOVDstoreidx,
+	[2]Op{OpS390XMOVWstore, OpS390XMOVDaddridx}: OpS390XMOVWstoreidx,
+	[2]Op{OpS390XMOVHstore, OpS390XMOVDaddridx}: OpS390XMOVHstoreidx,
+	[2]Op{OpS390XMOVBstore, OpS390XMOVDaddridx}: OpS390XMOVBstoreidx,
+
+	[2]Op{OpS390XMOVDBRstore, OpS390XMOVDaddridx}: OpS390XMOVDBRstoreidx,
+	[2]Op{OpS390XMOVWBRstore, OpS390XMOVDaddridx}: OpS390XMOVWBRstoreidx,
+	[2]Op{OpS390XMOVHBRstore, OpS390XMOVDaddridx}: OpS390XMOVHBRstoreidx,
+
+	[2]Op{OpS390XFMOVDstore, OpS390XMOVDaddridx}: OpS390XFMOVDstoreidx,
+	[2]Op{OpS390XFMOVSstore, OpS390XMOVDaddridx}: OpS390XFMOVSstoreidx,
 }

src/cmd/compile/internal/ssa/check.go

@@ -171,10 +171,10 @@ func checkFunc(f *Func) {
 				canHaveAuxInt = true
 				canHaveAux = true
 			case auxCCop:
-				if _, ok := v.Aux.(Op); !ok {
+				if opcodeTable[Op(v.AuxInt)].name == "OpInvalid" {
-					f.Fatalf("bad type %T for CCop in %v", v.Aux, v)
+					f.Fatalf("value %v has an AuxInt value that is a valid opcode", v)
 				}
-				canHaveAux = true
+				canHaveAuxInt = true
 			case auxS390XCCMask:
 				if _, ok := v.Aux.(s390x.CCMask); !ok {
 					f.Fatalf("bad type %T for S390XCCMask in %v", v.Aux, v)

src/cmd/compile/internal/ssa/config.go

@@ -173,6 +173,9 @@ type Frontend interface {
 	// SetWBPos indicates that a write barrier has been inserted
 	// in this function at position pos.
 	SetWBPos(pos src.XPos)
+
+	// MyImportPath provides the import name (roughly, the package) for the function being compiled.
+	MyImportPath() string
 }
 
 // interface used to hold a *gc.Node (a stack variable).

src/cmd/compile/internal/ssa/decompose.go

@@ -23,9 +23,11 @@ func decomposeBuiltIn(f *Func) {
 	}
 
 	// Decompose other values
-	applyRewrite(f, rewriteBlockdec, rewriteValuedec)
+	// Note: deadcode is false because we need to keep the original
+	// values around so the name component resolution below can still work.
+	applyRewrite(f, rewriteBlockdec, rewriteValuedec, leaveDeadValues)
 	if f.Config.RegSize == 4 {
-		applyRewrite(f, rewriteBlockdec64, rewriteValuedec64)
+		applyRewrite(f, rewriteBlockdec64, rewriteValuedec64, leaveDeadValues)
 	}
 
 	// Split up named values into their components.
@@ -139,7 +141,7 @@ func decomposeStringPhi(v *Value) {
 
 func decomposeSlicePhi(v *Value) {
 	types := &v.Block.Func.Config.Types
-	ptrType := types.BytePtr
+	ptrType := v.Type.Elem().PtrTo()
 	lenType := types.Int
 
 	ptr := v.Block.NewValue0(v.Pos, OpPhi, ptrType)
@@ -215,7 +217,7 @@ func decomposeInterfacePhi(v *Value) {
 }
 
 func decomposeArgs(f *Func) {
-	applyRewrite(f, rewriteBlockdecArgs, rewriteValuedecArgs)
+	applyRewrite(f, rewriteBlockdecArgs, rewriteValuedecArgs, removeDeadValues)
 }
 
 func decomposeUser(f *Func) {

src/cmd/compile/internal/ssa/export_test.go

@@ -146,6 +146,10 @@ func (d DummyFrontend) Fatalf(_ src.XPos, msg string, args ...interface{}) { d.t
 func (d DummyFrontend) Warnl(_ src.XPos, msg string, args ...interface{})  { d.t.Logf(msg, args...) }
 func (d DummyFrontend) Debug_checknil() bool                               { return false }
 
+func (d DummyFrontend) MyImportPath() string {
+	return "my/import/path"
+}
+
 var dummyTypes Types
 
 func init() {

src/cmd/compile/internal/ssa/func.go

@@ -257,6 +257,49 @@ func (f *Func) LogStat(key string, args ...interface{}) {
 	f.Warnl(f.Entry.Pos, "\t%s\t%s%s\t%s", n, key, value, f.Name)
 }
 
+// unCacheLine removes v from f's constant cache "line" for aux,
+// resets v.InCache when it is found (and removed),
+// and returns whether v was found in that line.
+func (f *Func) unCacheLine(v *Value, aux int64) bool {
+	vv := f.constants[aux]
+	for i, cv := range vv {
+		if v == cv {
+			vv[i] = vv[len(vv)-1]
+			vv[len(vv)-1] = nil
+			f.constants[aux] = vv[0 : len(vv)-1]
+			v.InCache = false
+			return true
+		}
+	}
+	return false
+}
+
+// unCache removes v from f's constant cache.
+func (f *Func) unCache(v *Value) {
+	if v.InCache {
+		aux := v.AuxInt
+		if f.unCacheLine(v, aux) {
+			return
+		}
+		if aux == 0 {
+			switch v.Op {
+			case OpConstNil:
+				aux = constNilMagic
+			case OpConstSlice:
+				aux = constSliceMagic
+			case OpConstString:
+				aux = constEmptyStringMagic
+			case OpConstInterface:
+				aux = constInterfaceMagic
+			}
+			if aux != 0 && f.unCacheLine(v, aux) {
+				return
+			}
+		}
+		f.Fatalf("unCached value %s not found in cache, auxInt=0x%x, adjusted aux=0x%x", v.LongString(), v.AuxInt, aux)
+	}
+}
+
 // freeValue frees a value. It must no longer be referenced or have any args.
 func (f *Func) freeValue(v *Value) {
 	if v.Block == nil {
@@ -270,19 +313,8 @@ func (f *Func) freeValue(v *Value) {
 	}
 	// Clear everything but ID (which we reuse).
 	id := v.ID
-
+	if v.InCache {
-	// Values with zero arguments and OpOffPtr values might be cached, so remove them there.
+		f.unCache(v)
-	nArgs := opcodeTable[v.Op].argLen
-	if nArgs == 0 || v.Op == OpOffPtr {
-		vv := f.constants[v.AuxInt]
-		for i, cv := range vv {
-			if v == cv {
-				vv[i] = vv[len(vv)-1]
-				vv[len(vv)-1] = nil
-				f.constants[v.AuxInt] = vv[0 : len(vv)-1]
-				break
-			}
-		}
 	}
 	*v = Value{}
 	v.ID = id
@@ -548,6 +580,7 @@ func (f *Func) constVal(op Op, t *types.Type, c int64, setAuxInt bool) *Value {
 		v = f.Entry.NewValue0(src.NoXPos, op, t)
 	}
 	f.constants[c] = append(vv, v)
+	v.InCache = true
 	return v
 }
 
@@ -678,7 +711,8 @@ func (f *Func) invalidateCFG() {
 //  GSHS_LOGFILE
 // or standard out if that is empty or there is an error
 // opening the file.
-func (f *Func) DebugHashMatch(evname, name string) bool {
+func (f *Func) DebugHashMatch(evname string) bool {
+	name := f.fe.MyImportPath() + "." + f.Name
 	evhash := os.Getenv(evname)
 	switch evhash {
 	case "":
@@ -727,7 +761,7 @@ func (f *Func) logDebugHashMatch(evname, name string) {
 		file = os.Stdout
 		if tmpfile := os.Getenv("GSHS_LOGFILE"); tmpfile != "" {
 			var err error
-			file, err = os.Create(tmpfile)
+			file, err = os.OpenFile(tmpfile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
 			if err != nil {
 				f.Fatalf("could not open hash-testing logfile %s", tmpfile)
 			}

src/cmd/compile/internal/ssa/gen/ARM.rules

@@ -1138,7 +1138,7 @@
 // ((x>>8) | (x<<8)) -> (REV16 x), the type of x is uint16, "|" can also be "^" or "+".
 // UBFX instruction is supported by ARMv6T2, ARMv7 and above versions, REV16 is supported by
 // ARMv6 and above versions. So for ARMv6, we need to match SLLconst, SRLconst and ORshiftLL.
-((ADDshiftLL|ORshiftLL|XORshiftLL) <typ.UInt16> [8] (BFXU <typ.UInt16> [armBFAuxInt(8, 8)] x) x) -> (REV16 x)
+((ADDshiftLL|ORshiftLL|XORshiftLL) <typ.UInt16> [8] (BFXU <typ.UInt16> [int32(armBFAuxInt(8, 8))] x) x) => (REV16 x)
 ((ADDshiftLL|ORshiftLL|XORshiftLL) <typ.UInt16> [8] (SRLconst <typ.UInt16> [24] (SLLconst [16] x)) x) && objabi.GOARM>=6 -> (REV16 x)
 
 // use indexed loads and stores

src/cmd/compile/internal/ssa/gen/ARM64Ops.go

@@ -467,8 +467,8 @@ func init() {
 
 		// conditional instructions; auxint is
 		// one of the arm64 comparison pseudo-ops (LessThan, LessThanU, etc.)
-		{name: "CSEL", argLength: 3, reg: gp2flags1, asm: "CSEL", aux: "CCop"},  // aux(flags) ? arg0 : arg1
+		{name: "CSEL", argLength: 3, reg: gp2flags1, asm: "CSEL", aux: "CCop"},  // auxint(flags) ? arg0 : arg1
-		{name: "CSEL0", argLength: 2, reg: gp1flags1, asm: "CSEL", aux: "CCop"}, // aux(flags) ? arg0 : 0
+		{name: "CSEL0", argLength: 2, reg: gp1flags1, asm: "CSEL", aux: "CCop"}, // auxint(flags) ? arg0 : 0
 
 		// function calls
 		{name: "CALLstatic", argLength: 1, reg: regInfo{clobbers: callerSave}, aux: "SymOff", clobberFlags: true, call: true, symEffect: "None"},                           // call static function aux.(*obj.LSym).  arg0=mem, auxint=argsize, returns mem

src/cmd/compile/internal/ssa/gen/MIPS64.rules

@@ -11,8 +11,8 @@
 (Mul(64|32|16|8) x y) => (Select1 (MULVU x y))
 (Mul(32|64)F ...) => (MUL(F|D) ...)
 (Mul64uhilo ...) => (MULVU ...)
-(Select0 (Mul64uover x y)) -> (Select1 <typ.UInt64> (MULVU x y))
+(Select0 (Mul64uover x y)) => (Select1 <typ.UInt64> (MULVU x y))
-(Select1 (Mul64uover x y)) -> (SGTU <typ.Bool> (Select0 <typ.UInt64> (MULVU x y)) (MOVVconst <typ.UInt64> [0]))
+(Select1 (Mul64uover x y)) => (SGTU <typ.Bool> (Select0 <typ.UInt64> (MULVU x y)) (MOVVconst <typ.UInt64> [0]))
 
 (Hmul64 x y) => (Select0 (MULV x y))
 (Hmul64u x y) => (Select0 (MULVU x y))
@@ -38,8 +38,8 @@
 (Mod8 x y) => (Select0 (DIVV (SignExt8to64 x) (SignExt8to64 y)))
 (Mod8u x y) => (Select0 (DIVVU (ZeroExt8to64 x) (ZeroExt8to64 y)))
 
-// (x + y) / 2 with x>=y -> (x - y) / 2 + y
+// (x + y) / 2 with x>=y => (x - y) / 2 + y
-(Avg64u <t> x y) -> (ADDV (SRLVconst <t> (SUBV <t> x y) [1]) y)
+(Avg64u <t> x y) => (ADDV (SRLVconst <t> (SUBV <t> x y) [1]) y)
 
 (And(64|32|16|8) ...) => (AND ...)
 (Or(64|32|16|8) ...) => (OR ...)
@@ -130,10 +130,10 @@
 (Not x) => (XORconst [1] x)
 
 // constants
-(Const(64|32|16|8) ...) -> (MOVVconst ...)
+(Const(64|32|16|8) [val]) => (MOVVconst [int64(val)])
-(Const(32|64)F ...) -> (MOV(F|D)const ...)
+(Const(32|64)F [val]) => (MOV(F|D)const [float64(val)])
 (ConstNil) => (MOVVconst [0])
-(ConstBool ...) -> (MOVVconst ...)
+(ConstBool [b]) => (MOVVconst [int64(b2i(b))])
 
 (Slicemask <t> x) => (SRAVconst (NEGV <t> x) [63])
 
@@ -161,7 +161,7 @@
 (SignExt16to64 ...) => (MOVHreg ...)
 (SignExt32to64 ...) => (MOVWreg ...)
 
-// float <-> int conversion
+// float <=> int conversion
 (Cvt32to32F ...) => (MOVWF ...)
 (Cvt32to64F ...) => (MOVWD ...)
 (Cvt64to32F ...) => (MOVVF ...)
@@ -214,11 +214,11 @@
 (Leq32U x y) => (XOR (MOVVconst [1]) (SGTU (ZeroExt32to64 x) (ZeroExt32to64 y)))
 (Leq64U x y) => (XOR (MOVVconst [1]) (SGTU x y))
 
-(OffPtr [off] ptr:(SP)) -> (MOVVaddr [off] ptr)
+(OffPtr [off] ptr:(SP)) && is32Bit(off) => (MOVVaddr [int32(off)] ptr)
-(OffPtr [off] ptr) -> (ADDVconst [off] ptr)
+(OffPtr [off] ptr) => (ADDVconst [off] ptr)
 
-(Addr ...) -> (MOVVaddr ...)
+(Addr {sym} base) => (MOVVaddr {sym} base)
-(LocalAddr {sym} base _) -> (MOVVaddr {sym} base)
+(LocalAddr {sym} base _) => (MOVVaddr {sym} base)
 
 // loads
 (Load <t> ptr mem) && t.IsBoolean() => (MOVBUload ptr mem)
@@ -380,24 +380,17 @@
 (InterCall ...) => (CALLinter ...)
 
 // atomic intrinsics
-(AtomicLoad8   ...) -> (LoweredAtomicLoad8  ...)
+(AtomicLoad(8|32|64) ...) => (LoweredAtomicLoad(8|32|64) ...)
-(AtomicLoad32  ...) -> (LoweredAtomicLoad32 ...)
+(AtomicLoadPtr ...) => (LoweredAtomicLoad64 ...)
-(AtomicLoad64  ...) -> (LoweredAtomicLoad64 ...)
-(AtomicLoadPtr ...) -> (LoweredAtomicLoad64 ...)
 
-(AtomicStore8       ...) -> (LoweredAtomicStore8  ...)
+(AtomicStore(8|32|64) ...) => (LoweredAtomicStore(8|32|64) ...)
-(AtomicStore32      ...) -> (LoweredAtomicStore32 ...)
+(AtomicStorePtrNoWB ...) => (LoweredAtomicStore64 ...)
-(AtomicStore64      ...) -> (LoweredAtomicStore64 ...)
-(AtomicStorePtrNoWB ...) -> (LoweredAtomicStore64 ...)
 
-(AtomicExchange32 ...) -> (LoweredAtomicExchange32 ...)
+(AtomicExchange(32|64) ...) => (LoweredAtomicExchange(32|64) ...)
-(AtomicExchange64 ...) -> (LoweredAtomicExchange64 ...)
 
-(AtomicAdd32 ...) -> (LoweredAtomicAdd32 ...)
+(AtomicAdd(32|64) ...) => (LoweredAtomicAdd(32|64) ...)
-(AtomicAdd64 ...) -> (LoweredAtomicAdd64 ...)
 
-(AtomicCompareAndSwap32 ...) -> (LoweredAtomicCas32 ...)
+(AtomicCompareAndSwap(32|64) ...) => (LoweredAtomicCas(32|64) ...)
-(AtomicCompareAndSwap64 ...) -> (LoweredAtomicCas64 ...)
 
 // checks
 (NilCheck ...) => (LoweredNilCheck ...)
@@ -444,69 +437,69 @@
 (EQ (SGT x (MOVVconst [0])) yes no) => (LEZ x yes no)
 
 // fold offset into address
-(ADDVconst [off1] (MOVVaddr [off2] {sym} ptr)) -> (MOVVaddr [off1+off2] {sym} ptr)
+(ADDVconst [off1] (MOVVaddr [off2] {sym} ptr)) && is32Bit(off1+int64(off2)) => (MOVVaddr [int32(off1)+int32(off2)] {sym} ptr)
 
 // fold address into load/store
-(MOVBload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVBload  [off1+off2] {sym} ptr mem)
+(MOVBload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVBload  [off1+int32(off2)] {sym} ptr mem)
-(MOVBUload [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVBUload [off1+off2] {sym} ptr mem)
+(MOVBUload [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVBUload [off1+int32(off2)] {sym} ptr mem)
-(MOVHload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVHload  [off1+off2] {sym} ptr mem)
+(MOVHload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVHload  [off1+int32(off2)] {sym} ptr mem)
-(MOVHUload [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVHUload [off1+off2] {sym} ptr mem)
+(MOVHUload [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVHUload [off1+int32(off2)] {sym} ptr mem)
-(MOVWload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVWload  [off1+off2] {sym} ptr mem)
+(MOVWload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVWload  [off1+int32(off2)] {sym} ptr mem)
-(MOVWUload [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVWUload [off1+off2] {sym} ptr mem)
+(MOVWUload [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVWUload [off1+int32(off2)] {sym} ptr mem)
-(MOVVload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVVload  [off1+off2] {sym} ptr mem)
+(MOVVload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVVload  [off1+int32(off2)] {sym} ptr mem)
-(MOVFload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVFload  [off1+off2] {sym} ptr mem)
+(MOVFload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVFload  [off1+int32(off2)] {sym} ptr mem)
-(MOVDload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVDload  [off1+off2] {sym} ptr mem)
+(MOVDload  [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVDload  [off1+int32(off2)] {sym} ptr mem)
 
-(MOVBstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVBstore [off1+off2] {sym} ptr val mem)
+(MOVBstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(int64(off1)+off2) => (MOVBstore [off1+int32(off2)] {sym} ptr val mem)
-(MOVHstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVHstore [off1+off2] {sym} ptr val mem)
+(MOVHstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(int64(off1)+off2) => (MOVHstore [off1+int32(off2)] {sym} ptr val mem)
-(MOVWstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVWstore [off1+off2] {sym} ptr val mem)
+(MOVWstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(int64(off1)+off2) => (MOVWstore [off1+int32(off2)] {sym} ptr val mem)
-(MOVVstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVVstore [off1+off2] {sym} ptr val mem)
+(MOVVstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(int64(off1)+off2) => (MOVVstore [off1+int32(off2)] {sym} ptr val mem)
-(MOVFstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVFstore [off1+off2] {sym} ptr val mem)
+(MOVFstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(int64(off1)+off2) => (MOVFstore [off1+int32(off2)] {sym} ptr val mem)
-(MOVDstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVDstore [off1+off2] {sym} ptr val mem)
+(MOVDstore [off1] {sym} (ADDVconst [off2] ptr) val mem) && is32Bit(int64(off1)+off2) => (MOVDstore [off1+int32(off2)] {sym} ptr val mem)
-(MOVBstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVBstorezero [off1+off2] {sym} ptr mem)
+(MOVBstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVBstorezero [off1+int32(off2)] {sym} ptr mem)
-(MOVHstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVHstorezero [off1+off2] {sym} ptr mem)
+(MOVHstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVHstorezero [off1+int32(off2)] {sym} ptr mem)
-(MOVWstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVWstorezero [off1+off2] {sym} ptr mem)
+(MOVWstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVWstorezero [off1+int32(off2)] {sym} ptr mem)
-(MOVVstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVVstorezero [off1+off2] {sym} ptr mem)
+(MOVVstorezero [off1] {sym} (ADDVconst [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVVstorezero [off1+int32(off2)] {sym} ptr mem)
 
-(MOVBload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVBload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVBload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVBload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVBUload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVBUload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVBUload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVBUload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVHload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVHload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVHload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVHload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVHUload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVHUload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVHUload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVHUload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVWload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVWload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVWload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVWload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVWUload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVWUload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVWUload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVWUload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVVload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVVload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVVload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVVload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVFload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVFload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVFload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVFload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVDload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVDload [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVDload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVDload [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
 
-(MOVBstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVBstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVBstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
+	(MOVBstore [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr val mem)
-(MOVHstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVHstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVHstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
+	(MOVHstore [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr val mem)
-(MOVWstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVWstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVWstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
+	(MOVWstore [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr val mem)
-(MOVVstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVVstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVVstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
+	(MOVVstore [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr val mem)
-(MOVFstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVFstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVFstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
+	(MOVFstore [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr val mem)
-(MOVDstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVDstore [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVDstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
+	(MOVDstore [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr val mem)
-(MOVBstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVBstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVBstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVBstorezero [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVHstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVHstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVHstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVHstorezero [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVWstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVWstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVWstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVWstorezero [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
-(MOVVstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(off1+off2) ->
+(MOVVstorezero [off1] {sym1} (MOVVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
-	(MOVVstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
+	(MOVVstorezero [off1+int32(off2)] {mergeSymTyped(sym1,sym2)} ptr mem)
 
 // store zero
 (MOVBstore [off] {sym} ptr (MOVVconst [0]) mem) => (MOVBstorezero [off] {sym} ptr mem)
@@ -643,10 +636,9 @@
 (MOVWreg  (MOVVconst [c])) => (MOVVconst [int64(int32(c))])
 (MOVWUreg (MOVVconst [c])) => (MOVVconst [int64(uint32(c))])
 (MOVVreg  (MOVVconst [c])) => (MOVVconst [c])
-(LoweredAtomicStore32 ptr (MOVVconst [0]) mem) -> (LoweredAtomicStorezero32 ptr mem)
+(LoweredAtomicStore(32|64) ptr (MOVVconst [0]) mem) => (LoweredAtomicStorezero(32|64) ptr mem)
-(LoweredAtomicStore64 ptr (MOVVconst [0]) mem) -> (LoweredAtomicStorezero64 ptr mem)
+(LoweredAtomicAdd32 ptr (MOVVconst [c]) mem) && is32Bit(c) => (LoweredAtomicAddconst32 [int32(c)] ptr mem)
-(LoweredAtomicAdd32 ptr (MOVVconst [c]) mem) && is32Bit(c) -> (LoweredAtomicAddconst32 [c] ptr mem)
+(LoweredAtomicAdd64 ptr (MOVVconst [c]) mem) && is32Bit(c) => (LoweredAtomicAddconst64 [c] ptr mem)
-(LoweredAtomicAdd64 ptr (MOVVconst [c]) mem) && is32Bit(c) -> (LoweredAtomicAddconst64 [c] ptr mem)
 
 // constant comparisons
 (SGTconst [c] (MOVVconst [d])) && c>d => (MOVVconst [1])

src/cmd/compile/internal/ssa/gen/PPC64.rules

@@ -110,13 +110,21 @@
 // Rotate generation with non-const shift
 // these match patterns from math/bits/RotateLeft[32|64], but there could be others
 (ADD (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))) => (ROTL x y)
+(ADD (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))) => (ROTL x y)
 ( OR (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))) => (ROTL x y)
+( OR (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))) => (ROTL x y)
 (XOR (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))) => (ROTL x y)
+(XOR (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))) => (ROTL x y)
 
+
+(ADD (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))) => (ROTLW x y)
 (ADD (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))) => (ROTLW x y)
+( OR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))) => (ROTLW x y)
 ( OR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))) => (ROTLW x y)
+(XOR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))) => (ROTLW x y)
 (XOR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))) => (ROTLW x y)
 
+
 // Lowering rotates
 (RotateLeft32 x y) => (ROTLW x y)
 (RotateLeft64 x y) => (ROTL x y)
@@ -192,11 +200,15 @@
 (Rsh64Ux64 x (AND y (MOVDconst [63]))) => (SRD x (ANDconst <typ.Int64> [63] y))
 (Rsh64Ux64 x (ANDconst <typ.UInt> [63] y)) => (SRD x (ANDconst <typ.UInt> [63] y))
 (Rsh64Ux64 x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y))) => (SRD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))
+(Rsh64Ux64 x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y))) => (SRD x (SUBFCconst <typ.UInt> [64]  (ANDconst <typ.UInt> [63] y)))
 (Rsh64Ux64 x (SUB <typ.UInt> (MOVDconst [64]) (AND <typ.UInt> y (MOVDconst [63])))) => (SRD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))
+(Rsh64Ux64 x (SUBFCconst <typ.UInt> [64] (AND <typ.UInt> y (MOVDconst [63])))) => (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
 (Rsh64x64 x (AND y (MOVDconst [63]))) => (SRAD x (ANDconst <typ.Int64> [63] y))
 (Rsh64x64 x (ANDconst <typ.UInt> [63] y)) => (SRAD x (ANDconst <typ.UInt> [63] y))
 (Rsh64x64 x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y))) => (SRAD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))
+(Rsh64x64 x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y))) => (SRAD x (SUBFCconst <typ.UInt> [64]  (ANDconst <typ.UInt> [63] y)))
 (Rsh64x64 x (SUB <typ.UInt> (MOVDconst [64]) (AND <typ.UInt> y (MOVDconst [63])))) => (SRAD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))
+(Rsh64x64 x (SUBFCconst <typ.UInt> [64] (AND <typ.UInt> y (MOVDconst [63])))) => (SRAD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
 
 (Lsh64x64 x y)  => (SLD  x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [64]))))
 (Rsh64x64 x y) => (SRAD x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [64]))))
@@ -208,12 +220,16 @@
 (Rsh32Ux64 x (AND y (MOVDconst [31]))) => (SRW x (ANDconst <typ.Int32> [31] y))
 (Rsh32Ux64 x (ANDconst <typ.UInt> [31] y)) => (SRW x (ANDconst <typ.UInt> [31] y))
 (Rsh32Ux64 x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y))) => (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))
+(Rsh32Ux64 x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y))) => (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
 (Rsh32Ux64 x (SUB <typ.UInt> (MOVDconst [32]) (AND <typ.UInt> y (MOVDconst [31])))) => (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))
+(Rsh32Ux64 x (SUBFCconst <typ.UInt> [32] (AND <typ.UInt> y (MOVDconst [31])))) => (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
 
 (Rsh32x64 x (AND y (MOVDconst [31]))) => (SRAW x (ANDconst <typ.Int32> [31] y))
 (Rsh32x64 x (ANDconst <typ.UInt> [31] y)) => (SRAW x (ANDconst <typ.UInt> [31] y))
 (Rsh32x64 x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y))) => (SRAW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))
+(Rsh32x64 x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y))) => (SRAW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
 (Rsh32x64 x (SUB <typ.UInt> (MOVDconst [32]) (AND <typ.UInt> y (MOVDconst [31])))) => (SRAW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))
+(Rsh32x64 x (SUBFCconst <typ.UInt> [32] (AND <typ.UInt> y (MOVDconst [31])))) => (SRAW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
 
 (Rsh32x64 x y)  => (SRAW x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [32]))))
 (Rsh32Ux64 x y) => (SRW  x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [32]))))
@@ -276,18 +292,11 @@
 (Rsh8Ux8 x y) => (SRW  (ZeroExt8to32 x) (ISEL [0] y (MOVDconst [-1]) (CMPU (ZeroExt8to64 y) (MOVDconst [8]))))
 (Lsh8x8 x y)  => (SLW  x                (ISEL [0] y (MOVDconst [-1]) (CMPU (ZeroExt8to64 y) (MOVDconst [8]))))
 
-// Cleaning up shift ops when input is masked
+// Cleaning up shift ops
-(MaskIfNotCarry (ADDconstForCarry [c] (ANDconst [d] _))) && c < 0 && d > 0 && int64(c) + d < 0 => (MOVDconst [-1])
 (ISEL [0] (ANDconst [d] y) (MOVDconst [-1]) (CMPU (ANDconst [d] y) (MOVDconst [c]))) && c >= d => (ANDconst [d] y)
 (ISEL [0] (ANDconst [d] y) (MOVDconst [-1]) (CMPUconst [c] (ANDconst [d] y))) && c >= d => (ANDconst [d] y)
 (ORN x (MOVDconst [-1])) => x
 
-(ADDconstForCarry [c] (MOVDconst [d])) && c < 0 && (c <  0 || int64(c) + d >= 0) => (FlagCarryClear)
-(ADDconstForCarry [c] (MOVDconst [d])) && c < 0 &&  c >= 0 && int64(c) + d <  0  => (FlagCarrySet)
-
-(MaskIfNotCarry (FlagCarrySet)) => (MOVDconst [0])
-(MaskIfNotCarry (FlagCarryClear)) => (MOVDconst [-1])
-
 (S(RAD|RD|LD) x (MOVDconst [c])) => (S(RAD|RD|LD)const [c&63 | (c>>6&1*63)] x)
 (S(RAW|RW|LW) x (MOVDconst [c])) => (S(RAW|RW|LW)const [c&31 | (c>>5&1*31)] x)
 
@@ -306,8 +315,8 @@
 (Ctz16 x) => (POPCNTW (MOVHZreg (ANDN <typ.Int16> (ADDconst <typ.Int16> [-1] x) x)))
 (Ctz8 x)  => (POPCNTB (MOVBZreg (ANDN <typ.UInt8> (ADDconst <typ.UInt8> [-1] x) x)))
 
-(BitLen64 x) => (SUB (MOVDconst [64]) (CNTLZD <typ.Int> x))
+(BitLen64 x) => (SUBFCconst [64] (CNTLZD <typ.Int> x))
-(BitLen32 x) => (SUB (MOVDconst [32]) (CNTLZW <typ.Int> x))
+(BitLen32 x) => (SUBFCconst [32] (CNTLZW <typ.Int> x))
 
 (PopCount64 ...) => (POPCNTD ...)
 (PopCount32 x) => (POPCNTW (MOVWZreg x))
@@ -777,10 +786,19 @@
 (ADDconst [c] (ADDconst [d] x)) && is32Bit(c+d) => (ADDconst [c+d] x)
 (ADDconst [0] x) => x
 (SUB x (MOVDconst [c])) && is32Bit(-c) => (ADDconst [-c] x)
-// TODO deal with subtract-from-const
 
 (ADDconst [c] (MOVDaddr [d] {sym} x)) && is32Bit(c+int64(d)) => (MOVDaddr [int32(c+int64(d))] {sym} x)
 
+// Subtract from (with carry, but ignored) constant.
+// Note, these clobber the carry bit.
+(SUB (MOVDconst [c]) x) && is32Bit(c) => (SUBFCconst [c] x)
+(SUBFCconst [c] (NEG x)) => (ADDconst [c] x)
+(SUBFCconst [c] (SUBFCconst [d] x)) && is32Bit(c-d) => (ADDconst [c-d] x)
+(SUBFCconst [0] x) => (NEG x)
+(ADDconst [c] (SUBFCconst [d] x)) && is32Bit(c+d) => (SUBFCconst [c+d] x)
+(NEG (ADDconst [c] x)) && is32Bit(-c) => (SUBFCconst [-c] x)
+(NEG (SUBFCconst [c] x)) && is32Bit(-c) => (ADDconst [-c] x)
+
 // Use register moves instead of stores and loads to move int<=>float values
 // Common with math Float64bits, Float64frombits
 (MOVDload [off] {sym} ptr (FMOVDstore [off] {sym} ptr x _)) => (MFVSRD x)

src/cmd/compile/internal/ssa/gen/PPC64Ops.go

@@ -175,6 +175,7 @@ func init() {
 		{name: "FADD", argLength: 2, reg: fp21, asm: "FADD", commutative: true},   // arg0+arg1
 		{name: "FADDS", argLength: 2, reg: fp21, asm: "FADDS", commutative: true}, // arg0+arg1
 		{name: "SUB", argLength: 2, reg: gp21, asm: "SUB"},                        // arg0-arg1
+		{name: "SUBFCconst", argLength: 1, reg: gp11, asm: "SUBC", aux: "Int64"},  // auxInt - arg0 (with carry)
 		{name: "FSUB", argLength: 2, reg: fp21, asm: "FSUB"},                      // arg0-arg1
 		{name: "FSUBS", argLength: 2, reg: fp21, asm: "FSUBS"},                    // arg0-arg1
 
@@ -206,9 +207,7 @@ func init() {
 		{name: "ROTL", argLength: 2, reg: gp21, asm: "ROTL"},   // arg0 rotate left by arg1 mod 64
 		{name: "ROTLW", argLength: 2, reg: gp21, asm: "ROTLW"}, // uint32(arg0) rotate left by arg1 mod 32
 
-		{name: "LoweredAdd64Carry", argLength: 3, reg: gp32, resultNotInArgs: true},                                                                     // arg0 + arg1 + carry, returns (sum, carry)
+		{name: "LoweredAdd64Carry", argLength: 3, reg: gp32, resultNotInArgs: true}, // arg0 + arg1 + carry, returns (sum, carry)
-		{name: "ADDconstForCarry", argLength: 1, reg: regInfo{inputs: []regMask{gp | sp | sb}, clobbers: tmp}, aux: "Int16", asm: "ADDC", typ: "Flags"}, // _, carry := arg0 + auxint
-		{name: "MaskIfNotCarry", argLength: 1, reg: crgp, asm: "ADDME", typ: "Int64"},                                                                   // carry - 1 (if carry then 0 else -1)
 
 		{name: "SRADconst", argLength: 1, reg: gp11, asm: "SRAD", aux: "Int64"}, // signed arg0 >> auxInt, 0 <= auxInt < 64, 64 bit width
 		{name: "SRAWconst", argLength: 1, reg: gp11, asm: "SRAW", aux: "Int64"}, // signed arg0 >> auxInt, 0 <= auxInt < 32, 32 bit width
@@ -674,11 +673,9 @@ func init() {
 
 		// These ops are for temporary use by rewrite rules. They
 		// cannot appear in the generated assembly.
-		{name: "FlagEQ"},         // equal
+		{name: "FlagEQ"}, // equal
-		{name: "FlagLT"},         // signed < or unsigned <
+		{name: "FlagLT"}, // signed < or unsigned <
-		{name: "FlagGT"},         // signed > or unsigned >
+		{name: "FlagGT"}, // signed > or unsigned >
-		{name: "FlagCarrySet"},   // carry flag set
-		{name: "FlagCarryClear"}, // carry flag clear
 	}
 
 	blocks := []blockData{

src/cmd/compile/internal/ssa/gen/Wasm.rules

@@ -377,6 +377,10 @@
 (I64Ne  (I64Const [x]) y) && y.Op != OpWasmI64Const => (I64Ne y  (I64Const [x]))
 
 (I64Eq x (I64Const [0])) => (I64Eqz x)
+(I64LtU (I64Const [0]) x) => (I64Eqz (I64Eqz x))
+(I64LeU x (I64Const [0])) => (I64Eqz x)
+(I64LtU x (I64Const [1])) => (I64Eqz x)
+(I64LeU (I64Const [1]) x) => (I64Eqz (I64Eqz x))
 (I64Ne x (I64Const [0])) => (I64Eqz (I64Eqz x))
 
 (I64Add x (I64Const [y])) => (I64AddConst [y] x)

src/cmd/compile/internal/ssa/gen/dec.rules

@@ -66,14 +66,14 @@
     (Load <typ.Int>
       (OffPtr <typ.IntPtr> [2*config.PtrSize] ptr)
       mem))
-(Store dst (SliceMake ptr len cap) mem) =>
+(Store {t} dst (SliceMake ptr len cap) mem) =>
   (Store {typ.Int}
     (OffPtr <typ.IntPtr> [2*config.PtrSize] dst)
     cap
     (Store {typ.Int}
       (OffPtr <typ.IntPtr> [config.PtrSize] dst)
       len
-      (Store {typ.BytePtr} dst ptr mem)))
+      (Store {t.Elem().PtrTo()} dst ptr mem)))
 
 // interface ops
 (ITab (IMake itab _)) => itab

src/cmd/compile/internal/ssa/gen/generic.rules

@@ -1807,6 +1807,8 @@
 // invariant that pointers must stay within the pointed-to object,
 // we can't pull part of a pointer computation above the AddPtr.
 // See issue 37881.
+// Note: we don't need to handle any (x-C) cases because we already rewrite
+// (x-C) to (x+(-C)).
 
 // x + (C + z) -> C + (x + z)
 (Add64 (Add64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Add64 <t> z x))
@@ -1820,23 +1822,29 @@
 (Add16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Sub16 <t> x z))
 (Add8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Sub8  <t> x z))
 
-// x + (z - C) -> (x + z) - C
-(Add64 (Sub64 z i:(Const64 <t>)) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 (Add64 <t> x z) i)
-(Add32 (Sub32 z i:(Const32 <t>)) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 (Add32 <t> x z) i)
-(Add16 (Sub16 z i:(Const16 <t>)) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 (Add16 <t> x z) i)
-(Add8  (Sub8  z i:(Const8  <t>)) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8  (Add8  <t> x z) i)
-
 // x - (C - z) -> x + (z - C) -> (x + z) - C
 (Sub64 x (Sub64 i:(Const64 <t>) z)) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 (Add64 <t> x z) i)
 (Sub32 x (Sub32 i:(Const32 <t>) z)) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 (Add32 <t> x z) i)
 (Sub16 x (Sub16 i:(Const16 <t>) z)) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 (Add16 <t> x z) i)
 (Sub8  x (Sub8  i:(Const8  <t>) z)) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8  (Add8  <t> x z) i)
 
-// x - (z - C) -> x + (C - z) -> (x - z) + C
+// x - (z + C) -> x + (-z - C) -> (x - z) - C
-(Sub64 x (Sub64 z i:(Const64 <t>))) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Sub64 <t> x z))
+(Sub64 x (Add64 z i:(Const64 <t>))) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 (Sub64 <t> x z) i)
-(Sub32 x (Sub32 z i:(Const32 <t>))) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Sub32 <t> x z))
+(Sub32 x (Add32 z i:(Const32 <t>))) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 (Sub32 <t> x z) i)
-(Sub16 x (Sub16 z i:(Const16 <t>))) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Sub16 <t> x z))
+(Sub16 x (Add16 z i:(Const16 <t>))) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 (Sub16 <t> x z) i)
-(Sub8  x (Sub8  z i:(Const8  <t>))) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Sub8  <t> x z))
+(Sub8  x (Add8  z i:(Const8  <t>))) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8 (Sub8  <t> x z) i)
+
+// (C - z) - x -> C - (z + x)
+(Sub64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 i (Add64 <t> z x))
+(Sub32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 i (Add32 <t> z x))
+(Sub16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 i (Add16 <t> z x))
+(Sub8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8  i (Add8  <t> z x))
+
+// (z + C) -x -> C + (z - x)
+(Sub64 (Add64 z i:(Const64 <t>)) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Sub64 <t> z x))
+(Sub32 (Add32 z i:(Const32 <t>)) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Sub32 <t> z x))
+(Sub16 (Add16 z i:(Const16 <t>)) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Sub16 <t> z x))
+(Sub8  (Add8  z i:(Const8  <t>)) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Sub8  <t> z x))
 
 // x & (C & z) -> C & (x & z)
 (And64 (And64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (And64 i (And64 <t> z x))
@@ -1856,6 +1864,12 @@
 (Xor16 (Xor16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Xor16 i (Xor16 <t> z x))
 (Xor8  (Xor8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Xor8  i (Xor8  <t> z x))
 
+// x * (D * z) = D * (x * z)
+(Mul64 (Mul64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Mul64 i (Mul64 <t> x z))
+(Mul32 (Mul32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Mul32 i (Mul32 <t> x z))
+(Mul16 (Mul16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Mul16 i (Mul16 <t> x z))
+(Mul8  (Mul8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Mul8  i (Mul8  <t> x z))
+
 // C + (D + x) -> (C + D) + x
 (Add64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c+d]) x)
 (Add32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c+d]) x)
@@ -1868,24 +1882,18 @@
 (Add16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c+d]) x)
 (Add8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c+d]) x)
 
-// C + (x - D) -> (C - D) + x
-(Add64 (Const64 <t> [c]) (Sub64 x (Const64 <t> [d]))) => (Add64 (Const64 <t> [c-d]) x)
-(Add32 (Const32 <t> [c]) (Sub32 x (Const32 <t> [d]))) => (Add32 (Const32 <t> [c-d]) x)
-(Add16 (Const16 <t> [c]) (Sub16 x (Const16 <t> [d]))) => (Add16 (Const16 <t> [c-d]) x)
-(Add8  (Const8  <t> [c]) (Sub8  x (Const8  <t> [d]))) => (Add8  (Const8  <t> [c-d]) x)
-
-// C - (x - D) -> (C + D) - x
-(Sub64 (Const64 <t> [c]) (Sub64 x (Const64 <t> [d]))) => (Sub64 (Const64 <t> [c+d]) x)
-(Sub32 (Const32 <t> [c]) (Sub32 x (Const32 <t> [d]))) => (Sub32 (Const32 <t> [c+d]) x)
-(Sub16 (Const16 <t> [c]) (Sub16 x (Const16 <t> [d]))) => (Sub16 (Const16 <t> [c+d]) x)
-(Sub8  (Const8  <t> [c]) (Sub8  x (Const8  <t> [d]))) => (Sub8  (Const8  <t> [c+d]) x)
-
 // C - (D - x) -> (C - D) + x
 (Sub64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c-d]) x)
 (Sub32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c-d]) x)
 (Sub16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Add16 (Const16 <t> [c-d]) x)
 (Sub8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Add8  (Const8  <t> [c-d]) x)
 
+// C - (D + x) -> (C - D) - x
+(Sub64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Sub64 (Const64 <t> [c-d]) x)
+(Sub32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Sub32 (Const32 <t> [c-d]) x)
+(Sub16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c-d]) x)
+(Sub8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c-d]) x)
+
 // C & (D & x) -> (C & D) & x
 (And64 (Const64 <t> [c]) (And64 (Const64 <t> [d]) x)) => (And64 (Const64 <t> [c&d]) x)
 (And32 (Const32 <t> [c]) (And32 (Const32 <t> [d]) x)) => (And32 (Const32 <t> [c&d]) x)

src/cmd/compile/internal/ssa/gen/rulegen.go

@@ -1423,7 +1423,8 @@ func parseValue(val string, arch arch, loc string) (op opData, oparch, typ, auxi
 
 func opHasAuxInt(op opData) bool {
 	switch op.aux {
-	case "Bool", "Int8", "Int16", "Int32", "Int64", "Int128", "Float32", "Float64", "SymOff", "SymValAndOff", "TypSize", "ARM64BitField", "FlagConstant":
+	case "Bool", "Int8", "Int16", "Int32", "Int64", "Int128", "Float32", "Float64",
+		"SymOff", "SymValAndOff", "TypSize", "ARM64BitField", "FlagConstant", "CCop":
 		return true
 	}
 	return false
@@ -1431,7 +1432,7 @@ func opHasAuxInt(op opData) bool {
 
 func opHasAux(op opData) bool {
 	switch op.aux {
-	case "String", "Sym", "SymOff", "SymValAndOff", "Typ", "TypSize", "CCop",
+	case "String", "Sym", "SymOff", "SymValAndOff", "Typ", "TypSize",
 		"S390XCCMask", "S390XRotateParams":
 		return true
 	}
@@ -1784,8 +1785,6 @@ func (op opData) auxType() string {
 		return "s390x.CCMask"
 	case "S390XRotateParams":
 		return "s390x.RotateParams"
-	case "CCop":
-		return "CCop"
 	default:
 		return "invalid"
 	}
@@ -1820,6 +1819,8 @@ func (op opData) auxIntType() string {
 		return "Op"
 	case "FlagConstant":
 		return "flagConstant"
+	case "ARM64BitField":
+		return "arm64BitField"
 	default:
 		return "invalid"
 	}

src/cmd/compile/internal/ssa/lower.go

@@ -7,7 +7,7 @@ package ssa
 // convert to machine-dependent ops
 func lower(f *Func) {
 	// repeat rewrites until we find no more rewrites
-	applyRewrite(f, f.Config.lowerBlock, f.Config.lowerValue)
+	applyRewrite(f, f.Config.lowerBlock, f.Config.lowerValue, removeDeadValues)
 }
 
 // checkLower checks for unlowered opcodes and fails if we find one.

src/cmd/compile/internal/ssa/nilcheck.go

@@ -235,7 +235,7 @@ func nilcheckelim2(f *Func) {
 				continue
 			}
 			if v.Type.IsMemory() || v.Type.IsTuple() && v.Type.FieldType(1).IsMemory() {
-				if v.Op == OpVarKill || v.Op == OpVarLive || (v.Op == OpVarDef && !v.Aux.(GCNode).Typ().HasHeapPointer()) {
+				if v.Op == OpVarKill || v.Op == OpVarLive || (v.Op == OpVarDef && !v.Aux.(GCNode).Typ().HasPointers()) {
 					// These ops don't really change memory.
 					continue
 					// Note: OpVarDef requires that the defined variable not have pointers.

src/cmd/compile/internal/ssa/op.go

@@ -277,3 +277,9 @@ func boundsABI(b int64) int {
 		panic("bad BoundsKind")
 	}
 }
+
+// arm64BitFileld is the GO type of ARM64BitField auxInt.
+// if x is an ARM64BitField, then width=x&0xff, lsb=(x>>8)&0xff, and
+// width+lsb<64 for 64-bit variant, width+lsb<32 for 32-bit variant.
+// the meaning of width and lsb are instruction-dependent.
+type arm64BitField int16

src/cmd/compile/internal/ssa/opGen.go

@@ -1828,6 +1828,7 @@ const (
 	OpPPC64FADD
 	OpPPC64FADDS
 	OpPPC64SUB
+	OpPPC64SUBFCconst
 	OpPPC64FSUB
 	OpPPC64FSUBS
 	OpPPC64MULLD
@@ -1853,8 +1854,6 @@ const (
 	OpPPC64ROTL
 	OpPPC64ROTLW
 	OpPPC64LoweredAdd64Carry
-	OpPPC64ADDconstForCarry
-	OpPPC64MaskIfNotCarry
 	OpPPC64SRADconst
 	OpPPC64SRAWconst
 	OpPPC64SRDconst
@@ -2027,8 +2026,6 @@ const (
 	OpPPC64FlagEQ
 	OpPPC64FlagLT
 	OpPPC64FlagGT
-	OpPPC64FlagCarrySet
-	OpPPC64FlagCarryClear
 
 	OpRISCV64ADD
 	OpRISCV64ADDI
@@ -24317,6 +24314,20 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:    "SUBFCconst",
+		auxType: auxInt64,
+		argLen:  1,
+		asm:     ppc64.ASUBC,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 1073733630}, // SP SB R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R14 R15 R16 R17 R18 R19 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29
+			},
+			outputs: []outputInfo{
+				{0, 1073733624}, // R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R14 R15 R16 R17 R18 R19 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29
+			},
+		},
+	},
 	{
 		name:   "FSUB",
 		argLen: 2,
@@ -24683,28 +24694,6 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
-	{
-		name:    "ADDconstForCarry",
-		auxType: auxInt16,
-		argLen:  1,
-		asm:     ppc64.AADDC,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 1073733630}, // SP SB R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R14 R15 R16 R17 R18 R19 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29
-			},
-			clobbers: 2147483648, // R31
-		},
-	},
-	{
-		name:   "MaskIfNotCarry",
-		argLen: 1,
-		asm:    ppc64.AADDME,
-		reg: regInfo{
-			outputs: []outputInfo{
-				{0, 1073733624}, // R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R14 R15 R16 R17 R18 R19 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29
-			},
-		},
-	},
 	{
 		name:    "SRADconst",
 		auxType: auxInt64,
@@ -26964,16 +26953,6 @@ var opcodeTable = [...]opInfo{
 		argLen: 0,
 		reg:    regInfo{},
 	},
-	{
-		name:   "FlagCarrySet",
-		argLen: 0,
-		reg:    regInfo{},
-	},
-	{
-		name:   "FlagCarryClear",
-		argLen: 0,
-		reg:    regInfo{},
-	},
 
 	{
 		name:        "ADD",

src/cmd/compile/internal/ssa/opt.go

@@ -6,5 +6,5 @@ package ssa
 
 // machine-independent optimization
 func opt(f *Func) {
-	applyRewrite(f, rewriteBlockgeneric, rewriteValuegeneric)
+	applyRewrite(f, rewriteBlockgeneric, rewriteValuegeneric, removeDeadValues)
 }

src/cmd/compile/internal/ssa/regalloc.go

@@ -588,7 +588,7 @@ func (s *regAllocState) init(f *Func) {
 	if s.f.Config.hasGReg {
 		s.allocatable &^= 1 << s.GReg
 	}
-	if s.f.Config.ctxt.Framepointer_enabled && s.f.Config.FPReg >= 0 {
+	if objabi.Framepointer_enabled && s.f.Config.FPReg >= 0 {
 		s.allocatable &^= 1 << uint(s.f.Config.FPReg)
 	}
 	if s.f.Config.LinkReg != -1 {

src/cmd/compile/internal/ssa/rewrite.go

@@ -20,7 +20,15 @@ import (
 	"path/filepath"
 )
 
-func applyRewrite(f *Func, rb blockRewriter, rv valueRewriter) {
+type deadValueChoice bool
+
+const (
+	leaveDeadValues  deadValueChoice = false
+	removeDeadValues                 = true
+)
+
+// deadcode indicates that rewrite should try to remove any values that become dead.
+func applyRewrite(f *Func, rb blockRewriter, rv valueRewriter, deadcode deadValueChoice) {
 	// repeat rewrites until we find no more rewrites
 	pendingLines := f.cachedLineStarts // Holds statement boundaries that need to be moved to a new value/block
 	pendingLines.clear()
@@ -56,6 +64,18 @@ func applyRewrite(f *Func, rb blockRewriter, rv valueRewriter) {
 					*v0 = *v
 					v0.Args = append([]*Value{}, v.Args...) // make a new copy, not aliasing
 				}
+				if v.Uses == 0 && v.removeable() {
+					if v.Op != OpInvalid && deadcode == removeDeadValues {
+						// Reset any values that are now unused, so that we decrement
+						// the use count of all of its arguments.
+						// Not quite a deadcode pass, because it does not handle cycles.
+						// But it should help Uses==1 rules to fire.
+						v.reset(OpInvalid)
+						change = true
+					}
+					// No point rewriting values which aren't used.
+					continue
+				}
 
 				vchange := phielimValue(v)
 				if vchange && debug > 1 {
@@ -618,6 +638,9 @@ func auxIntToFloat64(i int64) float64 {
 func auxIntToValAndOff(i int64) ValAndOff {
 	return ValAndOff(i)
 }
+func auxIntToArm64BitField(i int64) arm64BitField {
+	return arm64BitField(i)
+}
 func auxIntToInt128(x int64) int128 {
 	if x != 0 {
 		panic("nonzero int128 not allowed")
@@ -628,6 +651,10 @@ func auxIntToFlagConstant(x int64) flagConstant {
 	return flagConstant(x)
 }
 
+func auxIntToOp(cc int64) Op {
+	return Op(cc)
+}
+
 func boolToAuxInt(b bool) int64 {
 	if b {
 		return 1
@@ -658,6 +685,9 @@ func float64ToAuxInt(f float64) int64 {
 func valAndOffToAuxInt(v ValAndOff) int64 {
 	return int64(v)
 }
+func arm64BitFieldToAuxInt(v arm64BitField) int64 {
+	return int64(v)
+}
 func int128ToAuxInt(x int128) int64 {
 	if x != 0 {
 		panic("nonzero int128 not allowed")
@@ -668,6 +698,10 @@ func flagConstantToAuxInt(x flagConstant) int64 {
 	return int64(x)
 }
 
+func opToAuxInt(o Op) int64 {
+	return int64(o)
+}
+
 func auxToString(i interface{}) string {
 	return i.(string)
 }
@@ -701,9 +735,6 @@ func s390xCCMaskToAux(c s390x.CCMask) interface{} {
 func s390xRotateParamsToAux(r s390x.RotateParams) interface{} {
 	return r
 }
-func cCopToAux(o Op) interface{} {
-	return o
-}
 
 // uaddOvf reports whether unsigned a+b would overflow.
 func uaddOvf(a, b int64) bool {
@@ -1008,8 +1039,7 @@ func arm64Invert(op Op) Op {
 // evaluate an ARM64 op against a flags value
 // that is potentially constant; return 1 for true,
 // -1 for false, and 0 for not constant.
-func ccARM64Eval(cc interface{}, flags *Value) int {
+func ccARM64Eval(op Op, flags *Value) int {
-	op := cc.(Op)
 	fop := flags.Op
 	if fop == OpARM64InvertFlags {
 		return -ccARM64Eval(op, flags.Args[0])
@@ -1292,24 +1322,24 @@ func hasSmallRotate(c *Config) bool {
 }
 
 // encodes the lsb and width for arm(64) bitfield ops into the expected auxInt format.
-func armBFAuxInt(lsb, width int64) int64 {
+func armBFAuxInt(lsb, width int64) arm64BitField {
 	if lsb < 0 || lsb > 63 {
 		panic("ARM(64) bit field lsb constant out of range")
 	}
 	if width < 1 || width > 64 {
 		panic("ARM(64) bit field width constant out of range")
 	}
-	return width | lsb<<8
+	return arm64BitField(width | lsb<<8)
 }
 
 // returns the lsb part of the auxInt field of arm64 bitfield ops.
-func getARM64BFlsb(bfc int64) int64 {
+func (bfc arm64BitField) getARM64BFlsb() int64 {
 	return int64(uint64(bfc) >> 8)
 }
 
 // returns the width part of the auxInt field of arm64 bitfield ops.
-func getARM64BFwidth(bfc int64) int64 {
+func (bfc arm64BitField) getARM64BFwidth() int64 {
-	return bfc & 0xff
+	return int64(bfc) & 0xff
 }
 
 // checks if mask >> rshift applied at lsb is a valid arm64 bitfield op mask.

src/cmd/compile/internal/ssa/rewriteARM.go

@@ -2069,10 +2069,10 @@ func rewriteValueARM_OpARMADDshiftLL(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
-	// match: (ADDshiftLL <typ.UInt16> [8] (BFXU <typ.UInt16> [armBFAuxInt(8, 8)] x) x)
+	// match: (ADDshiftLL <typ.UInt16> [8] (BFXU <typ.UInt16> [int32(armBFAuxInt(8, 8))] x) x)
 	// result: (REV16 x)
 	for {
-		if v.Type != typ.UInt16 || v.AuxInt != 8 || v_0.Op != OpARMBFXU || v_0.Type != typ.UInt16 || v_0.AuxInt != armBFAuxInt(8, 8) {
+		if v.Type != typ.UInt16 || auxIntToInt32(v.AuxInt) != 8 || v_0.Op != OpARMBFXU || v_0.Type != typ.UInt16 || auxIntToInt32(v_0.AuxInt) != int32(armBFAuxInt(8, 8)) {
 			break
 		}
 		x := v_0.Args[0]
@@ -8537,10 +8537,10 @@ func rewriteValueARM_OpARMORshiftLL(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
-	// match: (ORshiftLL <typ.UInt16> [8] (BFXU <typ.UInt16> [armBFAuxInt(8, 8)] x) x)
+	// match: (ORshiftLL <typ.UInt16> [8] (BFXU <typ.UInt16> [int32(armBFAuxInt(8, 8))] x) x)
 	// result: (REV16 x)
 	for {
-		if v.Type != typ.UInt16 || v.AuxInt != 8 || v_0.Op != OpARMBFXU || v_0.Type != typ.UInt16 || v_0.AuxInt != armBFAuxInt(8, 8) {
+		if v.Type != typ.UInt16 || auxIntToInt32(v.AuxInt) != 8 || v_0.Op != OpARMBFXU || v_0.Type != typ.UInt16 || auxIntToInt32(v_0.AuxInt) != int32(armBFAuxInt(8, 8)) {
 			break
 		}
 		x := v_0.Args[0]
@@ -12576,10 +12576,10 @@ func rewriteValueARM_OpARMXORshiftLL(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
-	// match: (XORshiftLL <typ.UInt16> [8] (BFXU <typ.UInt16> [armBFAuxInt(8, 8)] x) x)
+	// match: (XORshiftLL <typ.UInt16> [8] (BFXU <typ.UInt16> [int32(armBFAuxInt(8, 8))] x) x)
 	// result: (REV16 x)
 	for {
-		if v.Type != typ.UInt16 || v.AuxInt != 8 || v_0.Op != OpARMBFXU || v_0.Type != typ.UInt16 || v_0.AuxInt != armBFAuxInt(8, 8) {
+		if v.Type != typ.UInt16 || auxIntToInt32(v.AuxInt) != 8 || v_0.Op != OpARMBFXU || v_0.Type != typ.UInt16 || auxIntToInt32(v_0.AuxInt) != int32(armBFAuxInt(8, 8)) {
 			break
 		}
 		x := v_0.Args[0]

src/cmd/compile/internal/ssa/rewritePPC64.go

@@ -428,8 +428,6 @@ func rewriteValuePPC64(v *Value) bool {
 		return rewriteValuePPC64_OpPPC64ADD(v)
 	case OpPPC64ADDconst:
 		return rewriteValuePPC64_OpPPC64ADDconst(v)
-	case OpPPC64ADDconstForCarry:
-		return rewriteValuePPC64_OpPPC64ADDconstForCarry(v)
 	case OpPPC64AND:
 		return rewriteValuePPC64_OpPPC64AND(v)
 	case OpPPC64ANDN:
@@ -570,8 +568,8 @@ func rewriteValuePPC64(v *Value) bool {
 		return rewriteValuePPC64_OpPPC64MOVWstorezero(v)
 	case OpPPC64MTVSRD:
 		return rewriteValuePPC64_OpPPC64MTVSRD(v)
-	case OpPPC64MaskIfNotCarry:
+	case OpPPC64NEG:
-		return rewriteValuePPC64_OpPPC64MaskIfNotCarry(v)
+		return rewriteValuePPC64_OpPPC64NEG(v)
 	case OpPPC64NOR:
 		return rewriteValuePPC64_OpPPC64NOR(v)
 	case OpPPC64NotEqual:
@@ -600,6 +598,8 @@ func rewriteValuePPC64(v *Value) bool {
 		return rewriteValuePPC64_OpPPC64SRW(v)
 	case OpPPC64SUB:
 		return rewriteValuePPC64_OpPPC64SUB(v)
+	case OpPPC64SUBFCconst:
+		return rewriteValuePPC64_OpPPC64SUBFCconst(v)
 	case OpPPC64XOR:
 		return rewriteValuePPC64_OpPPC64XOR(v)
 	case OpPPC64XORconst:
@@ -1025,15 +1025,14 @@ func rewriteValuePPC64_OpBitLen32(v *Value) bool {
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (BitLen32 x)
-	// result: (SUB (MOVDconst [32]) (CNTLZW <typ.Int> x))
+	// result: (SUBFCconst [32] (CNTLZW <typ.Int> x))
 	for {
 		x := v_0
-		v.reset(OpPPC64SUB)
+		v.reset(OpPPC64SUBFCconst)
-		v0 := b.NewValue0(v.Pos, OpPPC64MOVDconst, typ.Int64)
+		v.AuxInt = int64ToAuxInt(32)
-		v0.AuxInt = int64ToAuxInt(32)
+		v0 := b.NewValue0(v.Pos, OpPPC64CNTLZW, typ.Int)
-		v1 := b.NewValue0(v.Pos, OpPPC64CNTLZW, typ.Int)
+		v0.AddArg(x)
-		v1.AddArg(x)
+		v.AddArg(v0)
-		v.AddArg2(v0, v1)
 		return true
 	}
 }
@@ -1042,15 +1041,14 @@ func rewriteValuePPC64_OpBitLen64(v *Value) bool {
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (BitLen64 x)
-	// result: (SUB (MOVDconst [64]) (CNTLZD <typ.Int> x))
+	// result: (SUBFCconst [64] (CNTLZD <typ.Int> x))
 	for {
 		x := v_0
-		v.reset(OpPPC64SUB)
+		v.reset(OpPPC64SUBFCconst)
-		v0 := b.NewValue0(v.Pos, OpPPC64MOVDconst, typ.Int64)
+		v.AuxInt = int64ToAuxInt(64)
-		v0.AuxInt = int64ToAuxInt(64)
+		v0 := b.NewValue0(v.Pos, OpPPC64CNTLZD, typ.Int)
-		v1 := b.NewValue0(v.Pos, OpPPC64CNTLZD, typ.Int)
+		v0.AddArg(x)
-		v1.AddArg(x)
+		v.AddArg(v0)
-		v.AddArg2(v0, v1)
 		return true
 	}
 }
@@ -3961,6 +3959,76 @@ func rewriteValuePPC64_OpPPC64ADD(v *Value) bool {
 		}
 		break
 	}
+	// match: (ADD (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y))))
+	// result: (ROTL x y)
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpPPC64SLD {
+				continue
+			}
+			_ = v_0.Args[1]
+			x := v_0.Args[0]
+			v_0_1 := v_0.Args[1]
+			if v_0_1.Op != OpPPC64ANDconst || v_0_1.Type != typ.Int64 || auxIntToInt64(v_0_1.AuxInt) != 63 {
+				continue
+			}
+			y := v_0_1.Args[0]
+			if v_1.Op != OpPPC64SRD {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			v_1_1 := v_1.Args[1]
+			if v_1_1.Op != OpPPC64SUBFCconst || v_1_1.Type != typ.UInt || auxIntToInt64(v_1_1.AuxInt) != 64 {
+				continue
+			}
+			v_1_1_0 := v_1_1.Args[0]
+			if v_1_1_0.Op != OpPPC64ANDconst || v_1_1_0.Type != typ.UInt || auxIntToInt64(v_1_1_0.AuxInt) != 63 || y != v_1_1_0.Args[0] {
+				continue
+			}
+			v.reset(OpPPC64ROTL)
+			v.AddArg2(x, y)
+			return true
+		}
+		break
+	}
+	// match: (ADD (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y))))
+	// result: (ROTLW x y)
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpPPC64SLW {
+				continue
+			}
+			_ = v_0.Args[1]
+			x := v_0.Args[0]
+			v_0_1 := v_0.Args[1]
+			if v_0_1.Op != OpPPC64ANDconst || v_0_1.Type != typ.Int32 || auxIntToInt64(v_0_1.AuxInt) != 31 {
+				continue
+			}
+			y := v_0_1.Args[0]
+			if v_1.Op != OpPPC64SRW {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			v_1_1 := v_1.Args[1]
+			if v_1_1.Op != OpPPC64SUBFCconst || v_1_1.Type != typ.UInt || auxIntToInt64(v_1_1.AuxInt) != 32 {
+				continue
+			}
+			v_1_1_0 := v_1_1.Args[0]
+			if v_1_1_0.Op != OpPPC64ANDconst || v_1_1_0.Type != typ.UInt || auxIntToInt64(v_1_1_0.AuxInt) != 31 || y != v_1_1_0.Args[0] {
+				continue
+			}
+			v.reset(OpPPC64ROTLW)
+			v.AddArg2(x, y)
+			return true
+		}
+		break
+	}
 	// match: (ADD (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y))))
 	// result: (ROTLW x y)
 	for {
@@ -4073,38 +4141,22 @@ func rewriteValuePPC64_OpPPC64ADDconst(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
-	return false
+	// match: (ADDconst [c] (SUBFCconst [d] x))
-}
+	// cond: is32Bit(c+d)
-func rewriteValuePPC64_OpPPC64ADDconstForCarry(v *Value) bool {
+	// result: (SUBFCconst [c+d] x)
-	v_0 := v.Args[0]
-	// match: (ADDconstForCarry [c] (MOVDconst [d]))
-	// cond: c < 0 && (c < 0 || int64(c) + d >= 0)
-	// result: (FlagCarryClear)
 	for {
-		c := auxIntToInt16(v.AuxInt)
+		c := auxIntToInt64(v.AuxInt)
-		if v_0.Op != OpPPC64MOVDconst {
+		if v_0.Op != OpPPC64SUBFCconst {
 			break
 		}
 		d := auxIntToInt64(v_0.AuxInt)
-		if !(c < 0 && (c < 0 || int64(c)+d >= 0)) {
+		x := v_0.Args[0]
+		if !(is32Bit(c + d)) {
 			break
 		}
-		v.reset(OpPPC64FlagCarryClear)
+		v.reset(OpPPC64SUBFCconst)
-		return true
+		v.AuxInt = int64ToAuxInt(c + d)
-	}
+		v.AddArg(x)
-	// match: (ADDconstForCarry [c] (MOVDconst [d]))
-	// cond: c < 0 && c >= 0 && int64(c) + d < 0
-	// result: (FlagCarrySet)
-	for {
-		c := auxIntToInt16(v.AuxInt)
-		if v_0.Op != OpPPC64MOVDconst {
-			break
-		}
-		d := auxIntToInt64(v_0.AuxInt)
-		if !(c < 0 && c >= 0 && int64(c)+d < 0) {
-			break
-		}
-		v.reset(OpPPC64FlagCarrySet)
 		return true
 	}
 	return false
@@ -10374,46 +10426,40 @@ func rewriteValuePPC64_OpPPC64MTVSRD(v *Value) bool {
 	}
 	return false
 }
-func rewriteValuePPC64_OpPPC64MaskIfNotCarry(v *Value) bool {
+func rewriteValuePPC64_OpPPC64NEG(v *Value) bool {
 	v_0 := v.Args[0]
-	// match: (MaskIfNotCarry (ADDconstForCarry [c] (ANDconst [d] _)))
+	// match: (NEG (ADDconst [c] x))
-	// cond: c < 0 && d > 0 && int64(c) + d < 0
+	// cond: is32Bit(-c)
-	// result: (MOVDconst [-1])
+	// result: (SUBFCconst [-c] x)
 	for {
-		if v_0.Op != OpPPC64ADDconstForCarry {
+		if v_0.Op != OpPPC64ADDconst {
 			break
 		}
-		c := auxIntToInt16(v_0.AuxInt)
+		c := auxIntToInt64(v_0.AuxInt)
-		v_0_0 := v_0.Args[0]
+		x := v_0.Args[0]
-		if v_0_0.Op != OpPPC64ANDconst {
+		if !(is32Bit(-c)) {
 			break
 		}
-		d := auxIntToInt64(v_0_0.AuxInt)
+		v.reset(OpPPC64SUBFCconst)
-		if !(c < 0 && d > 0 && int64(c)+d < 0) {
+		v.AuxInt = int64ToAuxInt(-c)
-			break
+		v.AddArg(x)
-		}
-		v.reset(OpPPC64MOVDconst)
-		v.AuxInt = int64ToAuxInt(-1)
 		return true
 	}
-	// match: (MaskIfNotCarry (FlagCarrySet))
+	// match: (NEG (SUBFCconst [c] x))
-	// result: (MOVDconst [0])
+	// cond: is32Bit(-c)
+	// result: (ADDconst [-c] x)
 	for {
-		if v_0.Op != OpPPC64FlagCarrySet {
+		if v_0.Op != OpPPC64SUBFCconst {
 			break
 		}
-		v.reset(OpPPC64MOVDconst)
+		c := auxIntToInt64(v_0.AuxInt)
-		v.AuxInt = int64ToAuxInt(0)
+		x := v_0.Args[0]
-		return true
+		if !(is32Bit(-c)) {
-	}
-	// match: (MaskIfNotCarry (FlagCarryClear))
-	// result: (MOVDconst [-1])
-	for {
-		if v_0.Op != OpPPC64FlagCarryClear {
 			break
 		}
-		v.reset(OpPPC64MOVDconst)
+		v.reset(OpPPC64ADDconst)
-		v.AuxInt = int64ToAuxInt(-1)
+		v.AuxInt = int64ToAuxInt(-c)
+		v.AddArg(x)
 		return true
 	}
 	return false
@@ -10592,6 +10638,76 @@ func rewriteValuePPC64_OpPPC64OR(v *Value) bool {
 		}
 		break
 	}
+	// match: ( OR (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y))))
+	// result: (ROTL x y)
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpPPC64SLD {
+				continue
+			}
+			_ = v_0.Args[1]
+			x := v_0.Args[0]
+			v_0_1 := v_0.Args[1]
+			if v_0_1.Op != OpPPC64ANDconst || v_0_1.Type != typ.Int64 || auxIntToInt64(v_0_1.AuxInt) != 63 {
+				continue
+			}
+			y := v_0_1.Args[0]
+			if v_1.Op != OpPPC64SRD {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			v_1_1 := v_1.Args[1]
+			if v_1_1.Op != OpPPC64SUBFCconst || v_1_1.Type != typ.UInt || auxIntToInt64(v_1_1.AuxInt) != 64 {
+				continue
+			}
+			v_1_1_0 := v_1_1.Args[0]
+			if v_1_1_0.Op != OpPPC64ANDconst || v_1_1_0.Type != typ.UInt || auxIntToInt64(v_1_1_0.AuxInt) != 63 || y != v_1_1_0.Args[0] {
+				continue
+			}
+			v.reset(OpPPC64ROTL)
+			v.AddArg2(x, y)
+			return true
+		}
+		break
+	}
+	// match: ( OR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y))))
+	// result: (ROTLW x y)
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpPPC64SLW {
+				continue
+			}
+			_ = v_0.Args[1]
+			x := v_0.Args[0]
+			v_0_1 := v_0.Args[1]
+			if v_0_1.Op != OpPPC64ANDconst || v_0_1.Type != typ.Int32 || auxIntToInt64(v_0_1.AuxInt) != 31 {
+				continue
+			}
+			y := v_0_1.Args[0]
+			if v_1.Op != OpPPC64SRW {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			v_1_1 := v_1.Args[1]
+			if v_1_1.Op != OpPPC64SUBFCconst || v_1_1.Type != typ.UInt || auxIntToInt64(v_1_1.AuxInt) != 32 {
+				continue
+			}
+			v_1_1_0 := v_1_1.Args[0]
+			if v_1_1_0.Op != OpPPC64ANDconst || v_1_1_0.Type != typ.UInt || auxIntToInt64(v_1_1_0.AuxInt) != 31 || y != v_1_1_0.Args[0] {
+				continue
+			}
+			v.reset(OpPPC64ROTLW)
+			v.AddArg2(x, y)
+			return true
+		}
+		break
+	}
 	// match: ( OR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y))))
 	// result: (ROTLW x y)
 	for {
@@ -12191,6 +12307,69 @@ func rewriteValuePPC64_OpPPC64SUB(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
+	// match: (SUB (MOVDconst [c]) x)
+	// cond: is32Bit(c)
+	// result: (SUBFCconst [c] x)
+	for {
+		if v_0.Op != OpPPC64MOVDconst {
+			break
+		}
+		c := auxIntToInt64(v_0.AuxInt)
+		x := v_1
+		if !(is32Bit(c)) {
+			break
+		}
+		v.reset(OpPPC64SUBFCconst)
+		v.AuxInt = int64ToAuxInt(c)
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
+func rewriteValuePPC64_OpPPC64SUBFCconst(v *Value) bool {
+	v_0 := v.Args[0]
+	// match: (SUBFCconst [c] (NEG x))
+	// result: (ADDconst [c] x)
+	for {
+		c := auxIntToInt64(v.AuxInt)
+		if v_0.Op != OpPPC64NEG {
+			break
+		}
+		x := v_0.Args[0]
+		v.reset(OpPPC64ADDconst)
+		v.AuxInt = int64ToAuxInt(c)
+		v.AddArg(x)
+		return true
+	}
+	// match: (SUBFCconst [c] (SUBFCconst [d] x))
+	// cond: is32Bit(c-d)
+	// result: (ADDconst [c-d] x)
+	for {
+		c := auxIntToInt64(v.AuxInt)
+		if v_0.Op != OpPPC64SUBFCconst {
+			break
+		}
+		d := auxIntToInt64(v_0.AuxInt)
+		x := v_0.Args[0]
+		if !(is32Bit(c - d)) {
+			break
+		}
+		v.reset(OpPPC64ADDconst)
+		v.AuxInt = int64ToAuxInt(c - d)
+		v.AddArg(x)
+		return true
+	}
+	// match: (SUBFCconst [0] x)
+	// result: (NEG x)
+	for {
+		if auxIntToInt64(v.AuxInt) != 0 {
+			break
+		}
+		x := v_0
+		v.reset(OpPPC64NEG)
+		v.AddArg(x)
+		return true
+	}
 	return false
 }
 func rewriteValuePPC64_OpPPC64XOR(v *Value) bool {
@@ -12286,6 +12465,76 @@ func rewriteValuePPC64_OpPPC64XOR(v *Value) bool {
 		}
 		break
 	}
+	// match: (XOR (SLD x (ANDconst <typ.Int64> [63] y)) (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y))))
+	// result: (ROTL x y)
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpPPC64SLD {
+				continue
+			}
+			_ = v_0.Args[1]
+			x := v_0.Args[0]
+			v_0_1 := v_0.Args[1]
+			if v_0_1.Op != OpPPC64ANDconst || v_0_1.Type != typ.Int64 || auxIntToInt64(v_0_1.AuxInt) != 63 {
+				continue
+			}
+			y := v_0_1.Args[0]
+			if v_1.Op != OpPPC64SRD {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			v_1_1 := v_1.Args[1]
+			if v_1_1.Op != OpPPC64SUBFCconst || v_1_1.Type != typ.UInt || auxIntToInt64(v_1_1.AuxInt) != 64 {
+				continue
+			}
+			v_1_1_0 := v_1_1.Args[0]
+			if v_1_1_0.Op != OpPPC64ANDconst || v_1_1_0.Type != typ.UInt || auxIntToInt64(v_1_1_0.AuxInt) != 63 || y != v_1_1_0.Args[0] {
+				continue
+			}
+			v.reset(OpPPC64ROTL)
+			v.AddArg2(x, y)
+			return true
+		}
+		break
+	}
+	// match: (XOR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y))))
+	// result: (ROTLW x y)
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpPPC64SLW {
+				continue
+			}
+			_ = v_0.Args[1]
+			x := v_0.Args[0]
+			v_0_1 := v_0.Args[1]
+			if v_0_1.Op != OpPPC64ANDconst || v_0_1.Type != typ.Int32 || auxIntToInt64(v_0_1.AuxInt) != 31 {
+				continue
+			}
+			y := v_0_1.Args[0]
+			if v_1.Op != OpPPC64SRW {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			v_1_1 := v_1.Args[1]
+			if v_1_1.Op != OpPPC64SUBFCconst || v_1_1.Type != typ.UInt || auxIntToInt64(v_1_1.AuxInt) != 32 {
+				continue
+			}
+			v_1_1_0 := v_1_1.Args[0]
+			if v_1_1_0.Op != OpPPC64ANDconst || v_1_1_0.Type != typ.UInt || auxIntToInt64(v_1_1_0.AuxInt) != 31 || y != v_1_1_0.Args[0] {
+				continue
+			}
+			v.reset(OpPPC64ROTLW)
+			v.AddArg2(x, y)
+			return true
+		}
+		break
+	}
 	// match: (XOR (SLW x (ANDconst <typ.Int32> [31] y)) (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y))))
 	// result: (ROTLW x y)
 	for {
@@ -13257,6 +13506,28 @@ func rewriteValuePPC64_OpRsh32Ux64(v *Value) bool {
 		v.AddArg2(x, v0)
 		return true
 	}
+	// match: (Rsh32Ux64 x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
+	// result: (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 32 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64ANDconst || v_1_0.Type != typ.UInt || auxIntToInt64(v_1_0.AuxInt) != 31 {
+			break
+		}
+		y := v_1_0.Args[0]
+		v.reset(OpPPC64SRW)
+		v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+		v0.AuxInt = int64ToAuxInt(32)
+		v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+		v1.AuxInt = int64ToAuxInt(31)
+		v1.AddArg(y)
+		v0.AddArg(v1)
+		v.AddArg2(x, v0)
+		return true
+	}
 	// match: (Rsh32Ux64 x (SUB <typ.UInt> (MOVDconst [32]) (AND <typ.UInt> y (MOVDconst [31]))))
 	// result: (SRW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))
 	for {
@@ -13294,6 +13565,37 @@ func rewriteValuePPC64_OpRsh32Ux64(v *Value) bool {
 		}
 		break
 	}
+	// match: (Rsh32Ux64 x (SUBFCconst <typ.UInt> [32] (AND <typ.UInt> y (MOVDconst [31]))))
+	// result: (SRW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 32 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64AND || v_1_0.Type != typ.UInt {
+			break
+		}
+		_ = v_1_0.Args[1]
+		v_1_0_0 := v_1_0.Args[0]
+		v_1_0_1 := v_1_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_1_0_0, v_1_0_1 = _i0+1, v_1_0_1, v_1_0_0 {
+			y := v_1_0_0
+			if v_1_0_1.Op != OpPPC64MOVDconst || auxIntToInt64(v_1_0_1.AuxInt) != 31 {
+				continue
+			}
+			v.reset(OpPPC64SRW)
+			v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+			v0.AuxInt = int64ToAuxInt(32)
+			v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+			v1.AuxInt = int64ToAuxInt(31)
+			v1.AddArg(y)
+			v0.AddArg(v1)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
 	// match: (Rsh32Ux64 x y)
 	// result: (SRW x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [32]))))
 	for {
@@ -13564,6 +13866,28 @@ func rewriteValuePPC64_OpRsh32x64(v *Value) bool {
 		v.AddArg2(x, v0)
 		return true
 	}
+	// match: (Rsh32x64 x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
+	// result: (SRAW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 32 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64ANDconst || v_1_0.Type != typ.UInt || auxIntToInt64(v_1_0.AuxInt) != 31 {
+			break
+		}
+		y := v_1_0.Args[0]
+		v.reset(OpPPC64SRAW)
+		v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+		v0.AuxInt = int64ToAuxInt(32)
+		v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+		v1.AuxInt = int64ToAuxInt(31)
+		v1.AddArg(y)
+		v0.AddArg(v1)
+		v.AddArg2(x, v0)
+		return true
+	}
 	// match: (Rsh32x64 x (SUB <typ.UInt> (MOVDconst [32]) (AND <typ.UInt> y (MOVDconst [31]))))
 	// result: (SRAW x (SUB <typ.UInt> (MOVDconst [32]) (ANDconst <typ.UInt> [31] y)))
 	for {
@@ -13601,6 +13925,37 @@ func rewriteValuePPC64_OpRsh32x64(v *Value) bool {
 		}
 		break
 	}
+	// match: (Rsh32x64 x (SUBFCconst <typ.UInt> [32] (AND <typ.UInt> y (MOVDconst [31]))))
+	// result: (SRAW x (SUBFCconst <typ.UInt> [32] (ANDconst <typ.UInt> [31] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 32 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64AND || v_1_0.Type != typ.UInt {
+			break
+		}
+		_ = v_1_0.Args[1]
+		v_1_0_0 := v_1_0.Args[0]
+		v_1_0_1 := v_1_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_1_0_0, v_1_0_1 = _i0+1, v_1_0_1, v_1_0_0 {
+			y := v_1_0_0
+			if v_1_0_1.Op != OpPPC64MOVDconst || auxIntToInt64(v_1_0_1.AuxInt) != 31 {
+				continue
+			}
+			v.reset(OpPPC64SRAW)
+			v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+			v0.AuxInt = int64ToAuxInt(32)
+			v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+			v1.AuxInt = int64ToAuxInt(31)
+			v1.AddArg(y)
+			v0.AddArg(v1)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
 	// match: (Rsh32x64 x y)
 	// result: (SRAW x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [32]))))
 	for {
@@ -13869,6 +14224,28 @@ func rewriteValuePPC64_OpRsh64Ux64(v *Value) bool {
 		v.AddArg2(x, v0)
 		return true
 	}
+	// match: (Rsh64Ux64 x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
+	// result: (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 64 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64ANDconst || v_1_0.Type != typ.UInt || auxIntToInt64(v_1_0.AuxInt) != 63 {
+			break
+		}
+		y := v_1_0.Args[0]
+		v.reset(OpPPC64SRD)
+		v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+		v0.AuxInt = int64ToAuxInt(64)
+		v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+		v1.AuxInt = int64ToAuxInt(63)
+		v1.AddArg(y)
+		v0.AddArg(v1)
+		v.AddArg2(x, v0)
+		return true
+	}
 	// match: (Rsh64Ux64 x (SUB <typ.UInt> (MOVDconst [64]) (AND <typ.UInt> y (MOVDconst [63]))))
 	// result: (SRD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))
 	for {
@@ -13906,6 +14283,37 @@ func rewriteValuePPC64_OpRsh64Ux64(v *Value) bool {
 		}
 		break
 	}
+	// match: (Rsh64Ux64 x (SUBFCconst <typ.UInt> [64] (AND <typ.UInt> y (MOVDconst [63]))))
+	// result: (SRD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 64 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64AND || v_1_0.Type != typ.UInt {
+			break
+		}
+		_ = v_1_0.Args[1]
+		v_1_0_0 := v_1_0.Args[0]
+		v_1_0_1 := v_1_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_1_0_0, v_1_0_1 = _i0+1, v_1_0_1, v_1_0_0 {
+			y := v_1_0_0
+			if v_1_0_1.Op != OpPPC64MOVDconst || auxIntToInt64(v_1_0_1.AuxInt) != 63 {
+				continue
+			}
+			v.reset(OpPPC64SRD)
+			v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+			v0.AuxInt = int64ToAuxInt(64)
+			v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+			v1.AuxInt = int64ToAuxInt(63)
+			v1.AddArg(y)
+			v0.AddArg(v1)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
 	// match: (Rsh64Ux64 x y)
 	// result: (SRD x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [64]))))
 	for {
@@ -14176,6 +14584,28 @@ func rewriteValuePPC64_OpRsh64x64(v *Value) bool {
 		v.AddArg2(x, v0)
 		return true
 	}
+	// match: (Rsh64x64 x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
+	// result: (SRAD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 64 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64ANDconst || v_1_0.Type != typ.UInt || auxIntToInt64(v_1_0.AuxInt) != 63 {
+			break
+		}
+		y := v_1_0.Args[0]
+		v.reset(OpPPC64SRAD)
+		v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+		v0.AuxInt = int64ToAuxInt(64)
+		v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+		v1.AuxInt = int64ToAuxInt(63)
+		v1.AddArg(y)
+		v0.AddArg(v1)
+		v.AddArg2(x, v0)
+		return true
+	}
 	// match: (Rsh64x64 x (SUB <typ.UInt> (MOVDconst [64]) (AND <typ.UInt> y (MOVDconst [63]))))
 	// result: (SRAD x (SUB <typ.UInt> (MOVDconst [64]) (ANDconst <typ.UInt> [63] y)))
 	for {
@@ -14213,6 +14643,37 @@ func rewriteValuePPC64_OpRsh64x64(v *Value) bool {
 		}
 		break
 	}
+	// match: (Rsh64x64 x (SUBFCconst <typ.UInt> [64] (AND <typ.UInt> y (MOVDconst [63]))))
+	// result: (SRAD x (SUBFCconst <typ.UInt> [64] (ANDconst <typ.UInt> [63] y)))
+	for {
+		x := v_0
+		if v_1.Op != OpPPC64SUBFCconst || v_1.Type != typ.UInt || auxIntToInt64(v_1.AuxInt) != 64 {
+			break
+		}
+		v_1_0 := v_1.Args[0]
+		if v_1_0.Op != OpPPC64AND || v_1_0.Type != typ.UInt {
+			break
+		}
+		_ = v_1_0.Args[1]
+		v_1_0_0 := v_1_0.Args[0]
+		v_1_0_1 := v_1_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_1_0_0, v_1_0_1 = _i0+1, v_1_0_1, v_1_0_0 {
+			y := v_1_0_0
+			if v_1_0_1.Op != OpPPC64MOVDconst || auxIntToInt64(v_1_0_1.AuxInt) != 63 {
+				continue
+			}
+			v.reset(OpPPC64SRAD)
+			v0 := b.NewValue0(v.Pos, OpPPC64SUBFCconst, typ.UInt)
+			v0.AuxInt = int64ToAuxInt(64)
+			v1 := b.NewValue0(v.Pos, OpPPC64ANDconst, typ.UInt)
+			v1.AuxInt = int64ToAuxInt(63)
+			v1.AddArg(y)
+			v0.AddArg(v1)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
 	// match: (Rsh64x64 x y)
 	// result: (SRAD x (ISEL [0] y (MOVDconst [-1]) (CMPU y (MOVDconst [64]))))
 	for {

src/cmd/compile/internal/ssa/rewriteWasm.go

@@ -591,6 +591,8 @@ func rewriteValueWasm(v *Value) bool {
 		return rewriteValueWasm_OpWasmI64Eq(v)
 	case OpWasmI64Eqz:
 		return rewriteValueWasm_OpWasmI64Eqz(v)
+	case OpWasmI64LeU:
+		return rewriteValueWasm_OpWasmI64LeU(v)
 	case OpWasmI64Load:
 		return rewriteValueWasm_OpWasmI64Load(v)
 	case OpWasmI64Load16S:
@@ -605,6 +607,8 @@ func rewriteValueWasm(v *Value) bool {
 		return rewriteValueWasm_OpWasmI64Load8S(v)
 	case OpWasmI64Load8U:
 		return rewriteValueWasm_OpWasmI64Load8U(v)
+	case OpWasmI64LtU:
+		return rewriteValueWasm_OpWasmI64LtU(v)
 	case OpWasmI64Mul:
 		return rewriteValueWasm_OpWasmI64Mul(v)
 	case OpWasmI64Ne:
@@ -3824,6 +3828,37 @@ func rewriteValueWasm_OpWasmI64Eqz(v *Value) bool {
 	}
 	return false
 }
+func rewriteValueWasm_OpWasmI64LeU(v *Value) bool {
+	v_1 := v.Args[1]
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (I64LeU x (I64Const [0]))
+	// result: (I64Eqz x)
+	for {
+		x := v_0
+		if v_1.Op != OpWasmI64Const || auxIntToInt64(v_1.AuxInt) != 0 {
+			break
+		}
+		v.reset(OpWasmI64Eqz)
+		v.AddArg(x)
+		return true
+	}
+	// match: (I64LeU (I64Const [1]) x)
+	// result: (I64Eqz (I64Eqz x))
+	for {
+		if v_0.Op != OpWasmI64Const || auxIntToInt64(v_0.AuxInt) != 1 {
+			break
+		}
+		x := v_1
+		v.reset(OpWasmI64Eqz)
+		v0 := b.NewValue0(v.Pos, OpWasmI64Eqz, typ.Bool)
+		v0.AddArg(x)
+		v.AddArg(v0)
+		return true
+	}
+	return false
+}
 func rewriteValueWasm_OpWasmI64Load(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
@@ -4070,6 +4105,37 @@ func rewriteValueWasm_OpWasmI64Load8U(v *Value) bool {
 	}
 	return false
 }
+func rewriteValueWasm_OpWasmI64LtU(v *Value) bool {
+	v_1 := v.Args[1]
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (I64LtU (I64Const [0]) x)
+	// result: (I64Eqz (I64Eqz x))
+	for {
+		if v_0.Op != OpWasmI64Const || auxIntToInt64(v_0.AuxInt) != 0 {
+			break
+		}
+		x := v_1
+		v.reset(OpWasmI64Eqz)
+		v0 := b.NewValue0(v.Pos, OpWasmI64Eqz, typ.Bool)
+		v0.AddArg(x)
+		v.AddArg(v0)
+		return true
+	}
+	// match: (I64LtU x (I64Const [1]))
+	// result: (I64Eqz x)
+	for {
+		x := v_0
+		if v_1.Op != OpWasmI64Const || auxIntToInt64(v_1.AuxInt) != 1 {
+			break
+		}
+		v.reset(OpWasmI64Eqz)
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
 func rewriteValueWasm_OpWasmI64Mul(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]

src/cmd/compile/internal/ssa/rewritedec.go

@@ -328,9 +328,10 @@ func rewriteValuedec_OpStore(v *Value) bool {
 		v.AddArg3(v0, len, v1)
 		return true
 	}
-	// match: (Store dst (SliceMake ptr len cap) mem)
+	// match: (Store {t} dst (SliceMake ptr len cap) mem)
-	// result: (Store {typ.Int} (OffPtr <typ.IntPtr> [2*config.PtrSize] dst) cap (Store {typ.Int} (OffPtr <typ.IntPtr> [config.PtrSize] dst) len (Store {typ.BytePtr} dst ptr mem)))
+	// result: (Store {typ.Int} (OffPtr <typ.IntPtr> [2*config.PtrSize] dst) cap (Store {typ.Int} (OffPtr <typ.IntPtr> [config.PtrSize] dst) len (Store {t.Elem().PtrTo()} dst ptr mem)))
 	for {
+		t := auxToType(v.Aux)
 		dst := v_0
 		if v_1.Op != OpSliceMake {
 			break
@@ -350,7 +351,7 @@ func rewriteValuedec_OpStore(v *Value) bool {
 		v2.AuxInt = int64ToAuxInt(config.PtrSize)
 		v2.AddArg(dst)
 		v3 := b.NewValue0(v.Pos, OpStore, types.TypeMem)
-		v3.Aux = typeToAux(typ.BytePtr)
+		v3.Aux = typeToAux(t.Elem().PtrTo())
 		v3.AddArg3(dst, ptr, mem)
 		v1.AddArg3(v2, len, v3)
 		v.AddArg3(v0, cap, v1)

src/cmd/compile/internal/ssa/softfloat.go

@@ -18,6 +18,7 @@ func softfloat(f *Func) {
 	for _, b := range f.Blocks {
 		for _, v := range b.Values {
 			if v.Type.IsFloat() {
+				f.unCache(v)
 				switch v.Op {
 				case OpPhi, OpLoad, OpArg:
 					if v.Type.Size() == 4 {
@@ -72,7 +73,7 @@ func softfloat(f *Func) {
 	if newInt64 && f.Config.RegSize == 4 {
 		// On 32bit arch, decompose Uint64 introduced in the switch above.
 		decomposeBuiltIn(f)
-		applyRewrite(f, rewriteBlockdec64, rewriteValuedec64)
+		applyRewrite(f, rewriteBlockdec64, rewriteValuedec64, removeDeadValues)
 	}
 
 }

src/cmd/compile/internal/ssa/value.go

@@ -54,6 +54,9 @@ type Value struct {
 	// nor a slot on Go stack, and the generation of this value is delayed to its use time.
 	OnWasmStack bool
 
+	// Is this value in the per-function constant cache? If so, remove from cache before changing it or recycling it.
+	InCache bool
+
 	// Storage for the first three args
 	argstorage [3]*Value
 }
@@ -126,6 +129,13 @@ func (v *Value) AuxValAndOff() ValAndOff {
 	return ValAndOff(v.AuxInt)
 }
 
+func (v *Value) AuxArm64BitField() arm64BitField {
+	if opcodeTable[v.Op].auxType != auxARM64BitField {
+		v.Fatalf("op %s doesn't have a ValAndOff aux field", v.Op)
+	}
+	return arm64BitField(v.AuxInt)
+}
+
 // long form print.  v# = opcode <type> [aux] args [: reg] (names)
 func (v *Value) LongString() string {
 	s := fmt.Sprintf("v%d = %s", v.ID, v.Op)
@@ -176,8 +186,8 @@ func (v *Value) auxString() string {
 	case auxInt64, auxInt128:
 		return fmt.Sprintf(" [%d]", v.AuxInt)
 	case auxARM64BitField:
-		lsb := getARM64BFlsb(v.AuxInt)
+		lsb := v.AuxArm64BitField().getARM64BFlsb()
-		width := getARM64BFwidth(v.AuxInt)
+		width := v.AuxArm64BitField().getARM64BFwidth()
 		return fmt.Sprintf(" [lsb=%d,width=%d]", lsb, width)
 	case auxFloat32, auxFloat64:
 		return fmt.Sprintf(" [%g]", v.AuxFloat())
@@ -203,7 +213,7 @@ func (v *Value) auxString() string {
 		}
 		return s + fmt.Sprintf(" [%s]", v.AuxValAndOff())
 	case auxCCop:
-		return fmt.Sprintf(" {%s}", v.Aux.(Op))
+		return fmt.Sprintf(" {%s}", Op(v.AuxInt))
 	case auxS390XCCMask, auxS390XRotateParams:
 		return fmt.Sprintf(" {%v}", v.Aux)
 	case auxFlagConstant:
@@ -325,6 +335,9 @@ func (v *Value) resetArgs() {
 // of cmd/compile by almost 10%, and slows it down.
 //go:noinline
 func (v *Value) reset(op Op) {
+	if v.InCache {
+		v.Block.Func.unCache(v)
+	}
 	v.Op = op
 	v.resetArgs()
 	v.AuxInt = 0
@@ -335,6 +348,9 @@ func (v *Value) reset(op Op) {
 // It modifies v to be (Copy a).
 //go:noinline
 func (v *Value) copyOf(a *Value) {
+	if v.InCache {
+		v.Block.Func.unCache(v)
+	}
 	v.Op = OpCopy
 	v.resetArgs()
 	v.AddArg(a)
@@ -453,3 +469,23 @@ func (v *Value) LackingPos() bool {
 	return v.Op == OpVarDef || v.Op == OpVarKill || v.Op == OpVarLive || v.Op == OpPhi ||
 		(v.Op == OpFwdRef || v.Op == OpCopy) && v.Type == types.TypeMem
 }
+
+// removeable reports whether the value v can be removed from the SSA graph entirely
+// if its use count drops to 0.
+func (v *Value) removeable() bool {
+	if v.Type.IsVoid() {
+		// Void ops, like nil pointer checks, must stay.
+		return false
+	}
+	if v.Type.IsMemory() {
+		// All memory ops aren't needed here, but we do need
+		// to keep calls at least (because they might have
+		// syncronization operations we can't see).
+		return false
+	}
+	if v.Op.HasSideEffects() {
+		// These are mostly synchronization operations.
+		return false
+	}
+	return true
+}

src/cmd/compile/internal/ssa/writebarrier.go

@@ -31,7 +31,7 @@ func needwb(v *Value, zeroes map[ID]ZeroRegion) bool {
 	if !ok {
 		v.Fatalf("store aux is not a type: %s", v.LongString())
 	}
-	if !t.HasHeapPointer() {
+	if !t.HasPointers() {
 		return false
 	}
 	if IsStackAddr(v.Args[0]) {

src/cmd/compile/internal/types/type.go

@@ -1230,6 +1230,11 @@ func (t *Type) IsUnsafePtr() bool {
 	return t.Etype == TUNSAFEPTR
 }
 
+// IsUintptr reports whether t is an uintptr.
+func (t *Type) IsUintptr() bool {
+	return t.Etype == TUINTPTR
+}
+
 // IsPtrShaped reports whether t is represented by a single machine pointer.
 // In addition to regular Go pointer types, this includes map, channel, and
 // function types and unsafe.Pointer. It does not include array or struct types
@@ -1398,14 +1403,9 @@ func (t *Type) IsUntyped() bool {
 	return false
 }
 
-// TODO(austin): We probably only need HasHeapPointer. See
+// HasPointers reports whether t contains a heap pointer.
-// golang.org/cl/73412 for discussion.
+// Note that this function ignores pointers to go:notinheap types.
-
+func (t *Type) HasPointers() bool {
-func Haspointers(t *Type) bool {
-	return Haspointers1(t, false)
-}
-
-func Haspointers1(t *Type, ignoreNotInHeap bool) bool {
 	switch t.Etype {
 	case TINT, TUINT, TINT8, TUINT8, TINT16, TUINT16, TINT32, TUINT32, TINT64,
 		TUINT64, TUINTPTR, TFLOAT32, TFLOAT64, TCOMPLEX64, TCOMPLEX128, TBOOL, TSSA:
@@ -1415,34 +1415,27 @@ func Haspointers1(t *Type, ignoreNotInHeap bool) bool {
 		if t.NumElem() == 0 { // empty array has no pointers
 			return false
 		}
-		return Haspointers1(t.Elem(), ignoreNotInHeap)
+		return t.Elem().HasPointers()
 
 	case TSTRUCT:
 		for _, t1 := range t.Fields().Slice() {
-			if Haspointers1(t1.Type, ignoreNotInHeap) {
+			if t1.Type.HasPointers() {
 				return true
 			}
 		}
 		return false
 
 	case TPTR, TSLICE:
-		return !(ignoreNotInHeap && t.Elem().NotInHeap())
+		return !t.Elem().NotInHeap()
 
 	case TTUPLE:
 		ttup := t.Extra.(*Tuple)
-		return Haspointers1(ttup.first, ignoreNotInHeap) || Haspointers1(ttup.second, ignoreNotInHeap)
+		return ttup.first.HasPointers() || ttup.second.HasPointers()
 	}
 
 	return true
 }
 
-// HasHeapPointer reports whether t contains a heap pointer.
-// This is used for write barrier insertion, so it ignores
-// pointers to go:notinheap types.
-func (t *Type) HasHeapPointer() bool {
-	return Haspointers1(t, true)
-}
-
 func (t *Type) Symbol() *obj.LSym {
 	return TypeLinkSym(t)
 }
@@ -1471,7 +1464,7 @@ func FakeRecvType() *Type {
 }
 
 var (
-	// TSSA types. Haspointers assumes these are pointer-free.
+	// TSSA types. HasPointers assumes these are pointer-free.
 	TypeInvalid = newSSA("invalid")
 	TypeMem     = newSSA("mem")
 	TypeFlags   = newSSA("flags")

src/cmd/compile/internal/x86/ssa.go

@@ -261,8 +261,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 				n.To.Reg = x86.REG_DX
 			}
 
-			j.To.Val = n
+			j.To.SetTarget(n)
-			j2.To.Val = s.Pc()
+			j2.To.SetTarget(s.Pc())
 		}
 
 	case ssa.Op386HMULL, ssa.Op386HMULLU:

src/cmd/dist/test.go

@@ -1106,8 +1106,9 @@ func (t *tester) cgoTest(dt *distTest) error {
 
 		cmd := t.addCmd(dt, "misc/cgo/test", t.goTest())
 		cmd.Env = append(os.Environ(), "GOFLAGS=-ldflags=-linkmode=external")
-		// A -g argument in CGO_CFLAGS should not affect how the test runs.
+		// cgo should be able to cope with both -g arguments and colored
-		cmd.Env = append(cmd.Env, "CGO_CFLAGS=-g0")
+		// diagnostics.
+		cmd.Env = append(cmd.Env, "CGO_CFLAGS=-g0 -fdiagnostics-color")
 
 		t.addCmd(dt, "misc/cgo/testtls", t.goTest(), "-ldflags", "-linkmode=auto")
 		t.addCmd(dt, "misc/cgo/testtls", t.goTest(), "-ldflags", "-linkmode=external")

src/cmd/fix/fix.go

@@ -7,13 +7,9 @@ package main
 import (
 	"fmt"
 	"go/ast"
-	"go/parser"
 	"go/token"
-	"os"
 	"path"
-	"reflect"
 	"strconv"
-	"strings"
 )
 
 type fix struct {
@@ -323,160 +319,12 @@ func declImports(gen *ast.GenDecl, path string) bool {
 	return false
 }
 
-// isPkgDot reports whether t is the expression "pkg.name"
-// where pkg is an imported identifier.
-func isPkgDot(t ast.Expr, pkg, name string) bool {
-	sel, ok := t.(*ast.SelectorExpr)
-	return ok && isTopName(sel.X, pkg) && sel.Sel.String() == name
-}
-
-// isPtrPkgDot reports whether f is the expression "*pkg.name"
-// where pkg is an imported identifier.
-func isPtrPkgDot(t ast.Expr, pkg, name string) bool {
-	ptr, ok := t.(*ast.StarExpr)
-	return ok && isPkgDot(ptr.X, pkg, name)
-}
-
 // isTopName reports whether n is a top-level unresolved identifier with the given name.
 func isTopName(n ast.Expr, name string) bool {
 	id, ok := n.(*ast.Ident)
 	return ok && id.Name == name && id.Obj == nil
 }
 
-// isName reports whether n is an identifier with the given name.
-func isName(n ast.Expr, name string) bool {
-	id, ok := n.(*ast.Ident)
-	return ok && id.String() == name
-}
-
-// isCall reports whether t is a call to pkg.name.
-func isCall(t ast.Expr, pkg, name string) bool {
-	call, ok := t.(*ast.CallExpr)
-	return ok && isPkgDot(call.Fun, pkg, name)
-}
-
-// If n is an *ast.Ident, isIdent returns it; otherwise isIdent returns nil.
-func isIdent(n interface{}) *ast.Ident {
-	id, _ := n.(*ast.Ident)
-	return id
-}
-
-// refersTo reports whether n is a reference to the same object as x.
-func refersTo(n ast.Node, x *ast.Ident) bool {
-	id, ok := n.(*ast.Ident)
-	// The test of id.Name == x.Name handles top-level unresolved
-	// identifiers, which all have Obj == nil.
-	return ok && id.Obj == x.Obj && id.Name == x.Name
-}
-
-// isBlank reports whether n is the blank identifier.
-func isBlank(n ast.Expr) bool {
-	return isName(n, "_")
-}
-
-// isEmptyString reports whether n is an empty string literal.
-func isEmptyString(n ast.Expr) bool {
-	lit, ok := n.(*ast.BasicLit)
-	return ok && lit.Kind == token.STRING && len(lit.Value) == 2
-}
-
-func warn(pos token.Pos, msg string, args ...interface{}) {
-	if pos.IsValid() {
-		msg = "%s: " + msg
-		arg1 := []interface{}{fset.Position(pos).String()}
-		args = append(arg1, args...)
-	}
-	fmt.Fprintf(os.Stderr, msg+"\n", args...)
-}
-
-// countUses returns the number of uses of the identifier x in scope.
-func countUses(x *ast.Ident, scope []ast.Stmt) int {
-	count := 0
-	ff := func(n interface{}) {
-		if n, ok := n.(ast.Node); ok && refersTo(n, x) {
-			count++
-		}
-	}
-	for _, n := range scope {
-		walk(n, ff)
-	}
-	return count
-}
-
-// rewriteUses replaces all uses of the identifier x and !x in scope
-// with f(x.Pos()) and fnot(x.Pos()).
-func rewriteUses(x *ast.Ident, f, fnot func(token.Pos) ast.Expr, scope []ast.Stmt) {
-	var lastF ast.Expr
-	ff := func(n interface{}) {
-		ptr, ok := n.(*ast.Expr)
-		if !ok {
-			return
-		}
-		nn := *ptr
-
-		// The child node was just walked and possibly replaced.
-		// If it was replaced and this is a negation, replace with fnot(p).
-		not, ok := nn.(*ast.UnaryExpr)
-		if ok && not.Op == token.NOT && not.X == lastF {
-			*ptr = fnot(nn.Pos())
-			return
-		}
-		if refersTo(nn, x) {
-			lastF = f(nn.Pos())
-			*ptr = lastF
-		}
-	}
-	for _, n := range scope {
-		walk(n, ff)
-	}
-}
-
-// assignsTo reports whether any of the code in scope assigns to or takes the address of x.
-func assignsTo(x *ast.Ident, scope []ast.Stmt) bool {
-	assigned := false
-	ff := func(n interface{}) {
-		if assigned {
-			return
-		}
-		switch n := n.(type) {
-		case *ast.UnaryExpr:
-			// use of &x
-			if n.Op == token.AND && refersTo(n.X, x) {
-				assigned = true
-				return
-			}
-		case *ast.AssignStmt:
-			for _, l := range n.Lhs {
-				if refersTo(l, x) {
-					assigned = true
-					return
-				}
-			}
-		}
-	}
-	for _, n := range scope {
-		if assigned {
-			break
-		}
-		walk(n, ff)
-	}
-	return assigned
-}
-
-// newPkgDot returns an ast.Expr referring to "pkg.name" at position pos.
-func newPkgDot(pos token.Pos, pkg, name string) ast.Expr {
-	return &ast.SelectorExpr{
-		X: &ast.Ident{
-			NamePos: pos,
-			Name:    pkg,
-		},
-		Sel: &ast.Ident{
-			NamePos: pos,
-			Name:    name,
-		},
-	}
-}
-
 // renameTop renames all references to the top-level name old.
 // It reports whether it makes any changes.
 func renameTop(f *ast.File, old, new string) bool {
@@ -707,143 +555,3 @@ func rewriteImport(f *ast.File, oldPath, newPath string) (rewrote bool) {
 	}
 	return
 }
-
-func usesImport(f *ast.File, path string) (used bool) {
-	spec := importSpec(f, path)
-	if spec == nil {
-		return
-	}
-
-	name := spec.Name.String()
-	switch name {
-	case "<nil>":
-		// If the package name is not explicitly specified,
-		// make an educated guess. This is not guaranteed to be correct.
-		lastSlash := strings.LastIndex(path, "/")
-		if lastSlash == -1 {
-			name = path
-		} else {
-			name = path[lastSlash+1:]
-		}
-	case "_", ".":
-		// Not sure if this import is used - err on the side of caution.
-		return true
-	}
-
-	walk(f, func(n interface{}) {
-		sel, ok := n.(*ast.SelectorExpr)
-		if ok && isTopName(sel.X, name) {
-			used = true
-		}
-	})
-
-	return
-}
-
-func expr(s string) ast.Expr {
-	x, err := parser.ParseExpr(s)
-	if err != nil {
-		panic("parsing " + s + ": " + err.Error())
-	}
-	// Remove position information to avoid spurious newlines.
-	killPos(reflect.ValueOf(x))
-	return x
-}
-
-var posType = reflect.TypeOf(token.Pos(0))
-
-func killPos(v reflect.Value) {
-	switch v.Kind() {
-	case reflect.Ptr, reflect.Interface:
-		if !v.IsNil() {
-			killPos(v.Elem())
-		}
-	case reflect.Slice:
-		n := v.Len()
-		for i := 0; i < n; i++ {
-			killPos(v.Index(i))
-		}
-	case reflect.Struct:
-		n := v.NumField()
-		for i := 0; i < n; i++ {
-			f := v.Field(i)
-			if f.Type() == posType {
-				f.SetInt(0)
-				continue
-			}
-			killPos(f)
-		}
-	}
-}
-
-// A Rename describes a single renaming.
-type rename struct {
-	OldImport string // only apply rename if this import is present
-	NewImport string // add this import during rewrite
-	Old       string // old name: p.T or *p.T
-	New       string // new name: p.T or *p.T
-}
-
-func renameFix(tab []rename) func(*ast.File) bool {
-	return func(f *ast.File) bool {
-		return renameFixTab(f, tab)
-	}
-}
-
-func parseName(s string) (ptr bool, pkg, nam string) {
-	i := strings.Index(s, ".")
-	if i < 0 {
-		panic("parseName: invalid name " + s)
-	}
-	if strings.HasPrefix(s, "*") {
-		ptr = true
-		s = s[1:]
-		i--
-	}
-	pkg = s[:i]
-	nam = s[i+1:]
-	return
-}
-
-func renameFixTab(f *ast.File, tab []rename) bool {
-	fixed := false
-	added := map[string]bool{}
-	check := map[string]bool{}
-	for _, t := range tab {
-		if !imports(f, t.OldImport) {
-			continue
-		}
-		optr, opkg, onam := parseName(t.Old)
-		walk(f, func(n interface{}) {
-			np, ok := n.(*ast.Expr)
-			if !ok {
-				return
-			}
-			x := *np
-			if optr {
-				p, ok := x.(*ast.StarExpr)
-				if !ok {
-					return
-				}
-				x = p.X
-			}
-			if !isPkgDot(x, opkg, onam) {
-				return
-			}
-			if t.NewImport != "" && !added[t.NewImport] {
-				addImport(f, t.NewImport)
-				added[t.NewImport] = true
-			}
-			*np = expr(t.New)
-			check[t.OldImport] = true
-			fixed = true
-		})
-	}
-
-	for ipath := range check {
-		if !usesImport(f, ipath) {
-			deleteImport(f, ipath)
-		}
-	}
-	return fixed
-}

src/cmd/go.mod

@@ -7,8 +7,8 @@ require (
 	github.com/ianlancetaylor/demangle v0.0.0-20200414190113-039b1ae3a340 // indirect
 	golang.org/x/arch v0.0.0-20200511175325-f7c78586839d
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
-	golang.org/x/mod v0.3.1-0.20200625141748-0b26df4a2231
+	golang.org/x/mod v0.3.1-0.20200828183125-ce943fd02449
 	golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3 // indirect
-	golang.org/x/tools v0.0.0-20200616133436-c1934b75d054
+	golang.org/x/tools v0.0.0-20200901153117-6e59e24738da
 	golang.org/x/xerrors v0.0.0-20200806184451-1a77d5e9f316 // indirect
 )

src/cmd/go.sum

@@ -6,34 +6,34 @@ github.com/google/pprof v0.0.0-20200229191704-1ebb73c60ed3/go.mod h1:ZgVRPoUq/hf
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/ianlancetaylor/demangle v0.0.0-20200414190113-039b1ae3a340 h1:S1+yTUaFPXuDZnPDbO+TrDFIjPzQraYH8/CwSlu9Fac=
 github.com/ianlancetaylor/demangle v0.0.0-20200414190113-039b1ae3a340/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
-github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 golang.org/x/arch v0.0.0-20200511175325-f7c78586839d h1:YvwchuJby5xEAPdBGmdAVSiVME50C+RJfJJwJJsGEV8=
 golang.org/x/arch v0.0.0-20200511175325-f7c78586839d/go.mod h1:flIaEI6LNU6xOCD5PaJvn9wGP0agmIOqjrtsKGRguv4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9 h1:psW17arqaxU48Z5kZ0CQnkZWQJsqcURM6tKiBApRjXI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
-golang.org/x/mod v0.3.1-0.20200625141748-0b26df4a2231 h1:R11LxkoUvECaAHdM5/ZOevSR7n+016EgTw8nbE1l+XM=
+golang.org/x/mod v0.3.1-0.20200828183125-ce943fd02449 h1:xUIPaMhvROX9dhPvRCenIJtU78+lbEenGbgqB5hfHCQ=
-golang.org/x/mod v0.3.1-0.20200625141748-0b26df4a2231/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/mod v0.3.1-0.20200828183125-ce943fd02449/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200822124328-c89045814202/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3 h1:5B6i6EAiSYyejWfvc5Rc9BbI3rzIsrrXfAQBWnYfn+w=
 golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.0.0-20200616133436-c1934b75d054 h1:HHeAlu5H9b71C+Fx0K+1dGgVFN1DM1/wz4aoGOA5qS8=
+golang.org/x/tools v0.0.0-20200901153117-6e59e24738da h1:8nFbt74voFOsM+Hb5XtF+1SNbbf3dzikH5osZO1hyyo=
-golang.org/x/tools v0.0.0-20200616133436-c1934b75d054/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
+golang.org/x/tools v0.0.0-20200901153117-6e59e24738da/go.mod h1:Cj7w3i3Rnn0Xh82ur9kSqwfTHTeVxaDqrfMjpcNT6bE=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200806184451-1a77d5e9f316 h1:Jhw4VC65LaKnpq9FvcK+a8ZzrFm3D+UygvMMrhkOw70=
 golang.org/x/xerrors v0.0.0-20200806184451-1a77d5e9f316/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=

src/cmd/go/alldocs.go

@@ -916,6 +916,7 @@
 //         Dir       string       // directory holding files for this module, if any
 //         GoMod     string       // path to go.mod file used when loading this module, if any
 //         GoVersion string       // go version used in module
+//         Retracted string       // retraction information, if any (with -retracted or -u)
 //         Error     *ModuleError // error loading module
 //     }
 //
@@ -947,14 +948,16 @@
 // The -u flag adds information about available upgrades.
 // When the latest version of a given module is newer than
 // the current one, list -u sets the Module's Update field
-// to information about the newer module.
+// to information about the newer module. list -u will also set
+// the module's Retracted field if the current version is retracted.
 // The Module's String method indicates an available upgrade by
 // formatting the newer version in brackets after the current version.
+// If a version is retracted, the string "(retracted)" will follow it.
 // For example, 'go list -m -u all' might print:
 //
 //     my/main/module
 //     golang.org/x/text v0.3.0 [v0.4.0] => /tmp/text
-//     rsc.io/pdf v0.1.1 [v0.1.2]
+//     rsc.io/pdf v0.1.1 (retracted) [v0.1.2]
 //
 // (For tools, 'go list -m -u -json all' may be more convenient to parse.)
 //
@@ -964,6 +967,14 @@
 // the default output format to display the module path followed by the
 // space-separated version list.
 //
+// The -retracted flag causes list to report information about retracted
+// module versions. When -retracted is used with -f or -json, the Retracted
+// field will be set to a string explaining why the version was retracted.
+// The string is taken from comments on the retract directive in the
+// module's go.mod file. When -retracted is used with -versions, retracted
+// versions are listed together with unretracted versions. The -retracted
+// flag may be used with or without -m.
+//
 // The arguments to list -m are interpreted as a list of modules, not packages.
 // The main module is the module containing the current directory.
 // The active modules are the main module and its dependencies.
@@ -1100,9 +1111,14 @@
 // module path and version pair. If the @v is omitted, a replacement without
 // a version on the left side is dropped.
 //
+// The -retract=version and -dropretract=version flags add and drop a
+// retraction on the given version. The version may be a single version
+// like "v1.2.3" or a closed interval like "[v1.1.0-v1.1.9]". Note that
+// -retract=version is a no-op if that retraction already exists.
+//
 // The -require, -droprequire, -exclude, -dropexclude, -replace,
-// and -dropreplace editing flags may be repeated, and the changes
+// -dropreplace, -retract, and -dropretract editing flags may be repeated,
-// are applied in the order given.
+// and the changes are applied in the order given.
 //
 // The -go=version flag sets the expected Go language version.
 //
@@ -1136,6 +1152,15 @@
 // 		New Module
 // 	}
 //
+// 	type Retract struct {
+// 		Low       string
+// 		High      string
+// 		Rationale string
+// 	}
+//
+// Retract entries representing a single version (not an interval) will have
+// the "Low" and "High" fields set to the same value.
+//
 // Note that this only describes the go.mod file itself, not other modules
 // referred to indirectly. For the full set of modules available to a build,
 // use 'go list -m -json all'.
@@ -1894,15 +1919,17 @@
 // 	require new/thing/v2 v2.3.4
 // 	exclude old/thing v1.2.3
 // 	replace bad/thing v1.4.5 => good/thing v1.4.5
+// 	retract v1.5.6
 //
 // The verbs are
 // 	module, to define the module path;
 // 	go, to set the expected language version;
 // 	require, to require a particular module at a given version or later;
-// 	exclude, to exclude a particular module version from use; and
+// 	exclude, to exclude a particular module version from use;
-// 	replace, to replace a module version with a different module version.
+// 	replace, to replace a module version with a different module version; and
+// 	retract, to indicate a previously released version should not be used.
 // Exclude and replace apply only in the main module's go.mod and are ignored
-// in dependencies.  See https://research.swtch.com/vgo-mvs for details.
+// in dependencies.  See https://golang.org/ref/mod for details.
 //
 // The leading verb can be factored out of adjacent lines to create a block,
 // like in Go imports:
@@ -2145,7 +2172,10 @@
 // before resolving dependencies or building the code.
 //
 // The -insecure flag permits fetching from repositories and resolving
-// custom domains using insecure schemes such as HTTP. Use with caution.
+// custom domains using insecure schemes such as HTTP. Use with caution. The
+// GOINSECURE environment variable is usually a better alternative, since it
+// provides control over which modules may be retrieved using an insecure scheme.
+// See 'go help environment' for details.
 //
 // The -t flag instructs get to also download the packages required to build
 // the tests for the specified packages.

src/cmd/go/internal/base/flag.go

@@ -28,13 +28,42 @@ func (v *StringsFlag) String() string {
 	return "<StringsFlag>"
 }
 
+// explicitStringFlag is like a regular string flag, but it also tracks whether
+// the string was set explicitly to a non-empty value.
+type explicitStringFlag struct {
+	value    *string
+	explicit *bool
+}
+
+func (f explicitStringFlag) String() string {
+	if f.value == nil {
+		return ""
+	}
+	return *f.value
+}
+
+func (f explicitStringFlag) Set(v string) error {
+	*f.value = v
+	if v != "" {
+		*f.explicit = true
+	}
+	return nil
+}
+
 // AddBuildFlagsNX adds the -n and -x build flags to the flag set.
 func AddBuildFlagsNX(flags *flag.FlagSet) {
 	flags.BoolVar(&cfg.BuildN, "n", false, "")
 	flags.BoolVar(&cfg.BuildX, "x", false, "")
 }
 
-// AddLoadFlags adds the -mod build flag to the flag set.
+// AddModFlag adds the -mod build flag to the flag set.
-func AddLoadFlags(flags *flag.FlagSet) {
+func AddModFlag(flags *flag.FlagSet) {
-	flags.StringVar(&cfg.BuildMod, "mod", "", "")
+	flags.Var(explicitStringFlag{value: &cfg.BuildMod, explicit: &cfg.BuildModExplicit}, "mod", "")
+}
+
+// AddModCommonFlags adds the module-related flags common to build commands
+// and 'go mod' subcommands.
+func AddModCommonFlags(flags *flag.FlagSet) {
+	flags.BoolVar(&cfg.ModCacheRW, "modcacherw", false, "")
+	flags.StringVar(&cfg.ModFile, "modfile", "", "")
 }

src/cmd/go/internal/cfg/cfg.go

@@ -27,7 +27,8 @@ var (
 	BuildBuildmode         string // -buildmode flag
 	BuildContext           = defaultContext()
 	BuildMod               string             // -mod flag
-	BuildModReason         string             // reason -mod flag is set, if set by default
+	BuildModExplicit       bool               // whether -mod was set explicitly
+	BuildModReason         string             // reason -mod was set, if set by default
 	BuildI                 bool               // -i flag
 	BuildLinkshared        bool               // -linkshared flag
 	BuildMSan              bool               // -msan flag

src/cmd/go/internal/fmtcmd/fmt.go

@@ -23,7 +23,8 @@ import (
 
 func init() {
 	base.AddBuildFlagsNX(&CmdFmt.Flag)
-	base.AddLoadFlags(&CmdFmt.Flag)
+	base.AddModFlag(&CmdFmt.Flag)
+	base.AddModCommonFlags(&CmdFmt.Flag)
 }
 
 var CmdFmt = &base.Command{

src/cmd/go/internal/get/get.go

@@ -20,6 +20,8 @@ import (
 	"cmd/go/internal/str"
 	"cmd/go/internal/web"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/module"
 )
 
 var CmdGet = &base.Command{
@@ -41,7 +43,10 @@ The -fix flag instructs get to run the fix tool on the downloaded packages
 before resolving dependencies or building the code.
 
 The -insecure flag permits fetching from repositories and resolving
-custom domains using insecure schemes such as HTTP. Use with caution.
+custom domains using insecure schemes such as HTTP. Use with caution. The
+GOINSECURE environment variable is usually a better alternative, since it
+provides control over which modules may be retrieved using an insecure scheme.
+See 'go help environment' for details.
 
 The -t flag instructs get to also download the packages required to build
 the tests for the specified packages.
@@ -409,11 +414,6 @@ func downloadPackage(p *load.Package) error {
 		blindRepo      bool // set if the repo has unusual configuration
 	)
 
-	security := web.SecureOnly
-	if Insecure {
-		security = web.Insecure
-	}
-
 	// p can be either a real package, or a pseudo-package whose “import path” is
 	// actually a wildcard pattern.
 	// Trim the path at the element containing the first wildcard,
@@ -427,9 +427,13 @@ func downloadPackage(p *load.Package) error {
 		}
 		importPrefix = importPrefix[:slash]
 	}
-	if err := CheckImportPath(importPrefix); err != nil {
+	if err := module.CheckImportPath(importPrefix); err != nil {
 		return fmt.Errorf("%s: invalid import path: %v", p.ImportPath, err)
 	}
+	security := web.SecureOnly
+	if Insecure || module.MatchPrefixPatterns(cfg.GOINSECURE, importPrefix) {
+		security = web.Insecure
+	}
 
 	if p.Internal.Build.SrcRoot != "" {
 		// Directory exists. Look for checkout along path to src.
@@ -473,7 +477,7 @@ func downloadPackage(p *load.Package) error {
 		}
 		vcs, repo, rootPath = rr.vcs, rr.Repo, rr.Root
 	}
-	if !blindRepo && !vcs.isSecure(repo) && !Insecure {
+	if !blindRepo && !vcs.isSecure(repo) && security != web.Insecure {
 		return fmt.Errorf("cannot download, %v uses insecure protocol", repo)
 	}
 

src/cmd/go/internal/get/path.go

@@ -1,192 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package get
-
-import (
-	"fmt"
-	"strings"
-	"unicode"
-	"unicode/utf8"
-)
-
-// The following functions are copied verbatim from golang.org/x/mod/module/module.go,
-// with a change to additionally reject Windows short-names,
-// and one to accept arbitrary letters (golang.org/issue/29101).
-//
-// TODO(bcmills): After the call site for this function is backported,
-// consolidate this back down to a single copy.
-//
-// NOTE: DO NOT MERGE THESE UNTIL WE DECIDE ABOUT ARBITRARY LETTERS IN MODULE MODE.
-
-// CheckImportPath checks that an import path is valid.
-func CheckImportPath(path string) error {
-	if err := checkPath(path, false); err != nil {
-		return fmt.Errorf("malformed import path %q: %v", path, err)
-	}
-	return nil
-}
-
-// checkPath checks that a general path is valid.
-// It returns an error describing why but not mentioning path.
-// Because these checks apply to both module paths and import paths,
-// the caller is expected to add the "malformed ___ path %q: " prefix.
-// fileName indicates whether the final element of the path is a file name
-// (as opposed to a directory name).
-func checkPath(path string, fileName bool) error {
-	if !utf8.ValidString(path) {
-		return fmt.Errorf("invalid UTF-8")
-	}
-	if path == "" {
-		return fmt.Errorf("empty string")
-	}
-	if path[0] == '-' {
-		return fmt.Errorf("leading dash")
-	}
-	if strings.Contains(path, "//") {
-		return fmt.Errorf("double slash")
-	}
-	if path[len(path)-1] == '/' {
-		return fmt.Errorf("trailing slash")
-	}
-	elemStart := 0
-	for i, r := range path {
-		if r == '/' {
-			if err := checkElem(path[elemStart:i], fileName); err != nil {
-				return err
-			}
-			elemStart = i + 1
-		}
-	}
-	if err := checkElem(path[elemStart:], fileName); err != nil {
-		return err
-	}
-	return nil
-}
-
-// checkElem checks whether an individual path element is valid.
-// fileName indicates whether the element is a file name (not a directory name).
-func checkElem(elem string, fileName bool) error {
-	if elem == "" {
-		return fmt.Errorf("empty path element")
-	}
-	if strings.Count(elem, ".") == len(elem) {
-		return fmt.Errorf("invalid path element %q", elem)
-	}
-	if elem[0] == '.' && !fileName {
-		return fmt.Errorf("leading dot in path element")
-	}
-	if elem[len(elem)-1] == '.' {
-		return fmt.Errorf("trailing dot in path element")
-	}
-
-	charOK := pathOK
-	if fileName {
-		charOK = fileNameOK
-	}
-	for _, r := range elem {
-		if !charOK(r) {
-			return fmt.Errorf("invalid char %q", r)
-		}
-	}
-
-	// Windows disallows a bunch of path elements, sadly.
-	// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-	short := elem
-	if i := strings.Index(short, "."); i >= 0 {
-		short = short[:i]
-	}
-	for _, bad := range badWindowsNames {
-		if strings.EqualFold(bad, short) {
-			return fmt.Errorf("disallowed path element %q", elem)
-		}
-	}
-
-	// Reject path components that look like Windows short-names.
-	// Those usually end in a tilde followed by one or more ASCII digits.
-	if tilde := strings.LastIndexByte(short, '~'); tilde >= 0 && tilde < len(short)-1 {
-		suffix := short[tilde+1:]
-		suffixIsDigits := true
-		for _, r := range suffix {
-			if r < '0' || r > '9' {
-				suffixIsDigits = false
-				break
-			}
-		}
-		if suffixIsDigits {
-			return fmt.Errorf("trailing tilde and digits in path element")
-		}
-	}
-
-	return nil
-}
-
-// pathOK reports whether r can appear in an import path element.
-//
-// NOTE: This function DIVERGES from module mode pathOK by accepting Unicode letters.
-func pathOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		return r == '+' || r == '-' || r == '.' || r == '_' || r == '~' ||
-			'0' <= r && r <= '9' ||
-			'A' <= r && r <= 'Z' ||
-			'a' <= r && r <= 'z'
-	}
-	return unicode.IsLetter(r)
-}
-
-// fileNameOK reports whether r can appear in a file name.
-// For now we allow all Unicode letters but otherwise limit to pathOK plus a few more punctuation characters.
-// If we expand the set of allowed characters here, we have to
-// work harder at detecting potential case-folding and normalization collisions.
-// See note about "safe encoding" below.
-func fileNameOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		// Entire set of ASCII punctuation, from which we remove characters:
-		//     ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~
-		// We disallow some shell special characters: " ' * < > ? ` |
-		// (Note that some of those are disallowed by the Windows file system as well.)
-		// We also disallow path separators / : and \ (fileNameOK is only called on path element characters).
-		// We allow spaces (U+0020) in file names.
-		const allowed = "!#$%&()+,-.=@[]^_{}~ "
-		if '0' <= r && r <= '9' || 'A' <= r && r <= 'Z' || 'a' <= r && r <= 'z' {
-			return true
-		}
-		for i := 0; i < len(allowed); i++ {
-			if rune(allowed[i]) == r {
-				return true
-			}
-		}
-		return false
-	}
-	// It may be OK to add more ASCII punctuation here, but only carefully.
-	// For example Windows disallows < > \, and macOS disallows :, so we must not allow those.
-	return unicode.IsLetter(r)
-}
-
-// badWindowsNames are the reserved file path elements on Windows.
-// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-var badWindowsNames = []string{
-	"CON",
-	"PRN",
-	"AUX",
-	"NUL",
-	"COM1",
-	"COM2",
-	"COM3",
-	"COM4",
-	"COM5",
-	"COM6",
-	"COM7",
-	"COM8",
-	"COM9",
-	"LPT1",
-	"LPT2",
-	"LPT3",
-	"LPT4",
-	"LPT5",
-	"LPT6",
-	"LPT7",
-	"LPT8",
-	"LPT9",
-}

src/cmd/go/internal/get/vcs.go

@@ -1027,7 +1027,7 @@ var vcsPaths = []*vcsPath{
 	// Github
 	{
 		prefix: "github.com/",
-		regexp: lazyregexp.New(`^(?P<root>github\.com/[A-Za-z0-9_.\-]+/[A-Za-z0-9_.\-]+)(/[\p{L}0-9_.\-]+)*$`),
+		regexp: lazyregexp.New(`^(?P<root>github\.com/[A-Za-z0-9_.\-]+/[A-Za-z0-9_.\-]+)(/[A-Za-z0-9_.\-]+)*$`),
 		vcs:    "git",
 		repo:   "https://{root}",
 		check:  noVCSSuffix,

src/cmd/go/internal/get/vcs_test.go

@@ -32,13 +32,10 @@ func TestRepoRootForImportPath(t *testing.T) {
 				Repo: "https://github.com/golang/groupcache",
 			},
 		},
-		// Unicode letters in directories (issue 18660).
+		// Unicode letters in directories are not valid.
 		{
 			"github.com/user/unicode/испытание",
-			&RepoRoot{
+			nil,
-				vcs:  vcsGit,
-				Repo: "https://github.com/user/unicode",
-			},
 		},
 		// IBM DevOps Services tests
 		{

src/cmd/go/internal/list/list.go

@@ -10,6 +10,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"fmt"
 	"io"
 	"os"
 	"sort"
@@ -215,6 +216,7 @@ applied to a Go struct, but now a Module struct:
         Dir       string       // directory holding files for this module, if any
         GoMod     string       // path to go.mod file used when loading this module, if any
         GoVersion string       // go version used in module
+        Retracted string       // retraction information, if any (with -retracted or -u)
         Error     *ModuleError // error loading module
     }
 
@@ -246,14 +248,16 @@ the replaced source code.)
 The -u flag adds information about available upgrades.
 When the latest version of a given module is newer than
 the current one, list -u sets the Module's Update field
-to information about the newer module.
+to information about the newer module. list -u will also set
+the module's Retracted field if the current version is retracted.
 The Module's String method indicates an available upgrade by
 formatting the newer version in brackets after the current version.
+If a version is retracted, the string "(retracted)" will follow it.
 For example, 'go list -m -u all' might print:
 
     my/main/module
     golang.org/x/text v0.3.0 [v0.4.0] => /tmp/text
-    rsc.io/pdf v0.1.1 [v0.1.2]
+    rsc.io/pdf v0.1.1 (retracted) [v0.1.2]
 
 (For tools, 'go list -m -u -json all' may be more convenient to parse.)
 
@@ -263,6 +267,14 @@ to semantic versioning, earliest to latest. The flag also changes
 the default output format to display the module path followed by the
 space-separated version list.
 
+The -retracted flag causes list to report information about retracted
+module versions. When -retracted is used with -f or -json, the Retracted
+field will be set to a string explaining why the version was retracted.
+The string is taken from comments on the retract directive in the
+module's go.mod file. When -retracted is used with -versions, retracted
+versions are listed together with unretracted versions. The -retracted
+flag may be used with or without -m.
+
 The arguments to list -m are interpreted as a list of modules, not packages.
 The main module is the module containing the current directory.
 The active modules are the main module and its dependencies.
@@ -296,17 +308,18 @@ func init() {
 }
 
 var (
-	listCompiled = CmdList.Flag.Bool("compiled", false, "")
+	listCompiled  = CmdList.Flag.Bool("compiled", false, "")
-	listDeps     = CmdList.Flag.Bool("deps", false, "")
+	listDeps      = CmdList.Flag.Bool("deps", false, "")
-	listE        = CmdList.Flag.Bool("e", false, "")
+	listE         = CmdList.Flag.Bool("e", false, "")
-	listExport   = CmdList.Flag.Bool("export", false, "")
+	listExport    = CmdList.Flag.Bool("export", false, "")
-	listFmt      = CmdList.Flag.String("f", "", "")
+	listFmt       = CmdList.Flag.String("f", "", "")
-	listFind     = CmdList.Flag.Bool("find", false, "")
+	listFind      = CmdList.Flag.Bool("find", false, "")
-	listJson     = CmdList.Flag.Bool("json", false, "")
+	listJson      = CmdList.Flag.Bool("json", false, "")
-	listM        = CmdList.Flag.Bool("m", false, "")
+	listM         = CmdList.Flag.Bool("m", false, "")
-	listU        = CmdList.Flag.Bool("u", false, "")
+	listRetracted = CmdList.Flag.Bool("retracted", false, "")
-	listTest     = CmdList.Flag.Bool("test", false, "")
+	listTest      = CmdList.Flag.Bool("test", false, "")
-	listVersions = CmdList.Flag.Bool("versions", false, "")
+	listU         = CmdList.Flag.Bool("u", false, "")
+	listVersions  = CmdList.Flag.Bool("versions", false, "")
 )
 
 var nl = []byte{'\n'}
@@ -367,6 +380,16 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}
 
+	modload.Init()
+	if *listRetracted {
+		if cfg.BuildMod == "vendor" {
+			base.Fatalf("go list -retracted cannot be used when vendoring is enabled")
+		}
+		if !modload.Enabled() {
+			base.Fatalf("go list -retracted can only be used in module-aware mode")
+		}
+	}
+
 	if *listM {
 		// Module mode.
 		if *listCompiled {
@@ -414,9 +437,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 			}
 		}
 
-		modload.LoadBuildList(ctx)
+		mods := modload.ListModules(ctx, args, *listU, *listVersions, *listRetracted)
-
-		mods := modload.ListModules(ctx, args, *listU, *listVersions)
 		if !*listE {
 			for _, m := range mods {
 				if m.Error != nil {
@@ -522,7 +543,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		// Note that -deps is applied after -test,
 		// so that you only get descriptions of tests for the things named
 		// explicitly on the command line, not for all dependencies.
-		pkgs = load.PackageList(pkgs)
+		pkgs = loadPackageList(pkgs)
 	}
 
 	// Do we need to run a build to gather information?
@@ -557,7 +578,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 	if *listTest {
 		all := pkgs
 		if !*listDeps {
-			all = load.PackageList(pkgs)
+			all = loadPackageList(pkgs)
 		}
 		// Update import paths to distinguish the real package p
 		// from p recompiled for q.test.
@@ -607,6 +628,55 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}
 
+	// TODO(golang.org/issue/40676): This mechanism could be extended to support
+	// -u without -m.
+	if *listRetracted {
+		// Load retractions for modules that provide packages that will be printed.
+		// TODO(golang.org/issue/40775): Packages from the same module refer to
+		// distinct ModulePublic instance. It would be nice if they could all point
+		// to the same instance. This would require additional global state in
+		// modload.loaded, so that should be refactored first. For now, we update
+		// all instances.
+		modToArg := make(map[*modinfo.ModulePublic]string)
+		argToMods := make(map[string][]*modinfo.ModulePublic)
+		var args []string
+		addModule := func(mod *modinfo.ModulePublic) {
+			if mod.Version == "" {
+				return
+			}
+			arg := fmt.Sprintf("%s@%s", mod.Path, mod.Version)
+			if argToMods[arg] == nil {
+				args = append(args, arg)
+			}
+			argToMods[arg] = append(argToMods[arg], mod)
+			modToArg[mod] = arg
+		}
+		for _, p := range pkgs {
+			if p.Module == nil {
+				continue
+			}
+			addModule(p.Module)
+			if p.Module.Replace != nil {
+				addModule(p.Module.Replace)
+			}
+		}
+
+		if len(args) > 0 {
+			listU := false
+			listVersions := false
+			rmods := modload.ListModules(ctx, args, listU, listVersions, *listRetracted)
+			for i, arg := range args {
+				rmod := rmods[i]
+				for _, mod := range argToMods[arg] {
+					mod.Retracted = rmod.Retracted
+					if rmod.Error != nil && mod.Error == nil {
+						mod.Error = rmod.Error
+					}
+				}
+			}
+		}
+	}
+
 	// Record non-identity import mappings in p.ImportMap.
 	for _, p := range pkgs {
 		for i, srcPath := range p.Internal.RawImports {
@@ -625,6 +695,23 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 	}
 }
 
+// loadPackageList is like load.PackageList, but prints error messages and exits
+// with nonzero status if listE is not set and any package in the expanded list
+// has errors.
+func loadPackageList(roots []*load.Package) []*load.Package {
+	pkgs := load.PackageList(roots)
+
+	if !*listE {
+		for _, pkg := range pkgs {
+			if pkg.Error != nil {
+				base.Errorf("%v", pkg.Error)
+			}
+		}
+	}
+
+	return pkgs
+}
+
 // TrackingWriter tracks the last byte written on every write so
 // we can avoid printing a newline if one was already written or
 // if there is no output at all.

src/cmd/go/internal/load/test.go

@@ -191,6 +191,7 @@ func TestPackagesAndErrors(ctx context.Context, p *Package, cover *TestCover) (p
 				GoFiles:    p.XTestGoFiles,
 				Imports:    p.XTestImports,
 				ForTest:    p.ImportPath,
+				Module:     p.Module,
 				Error:      pxtestErr,
 			},
 			Internal: PackageInternal{
@@ -222,6 +223,7 @@ func TestPackagesAndErrors(ctx context.Context, p *Package, cover *TestCover) (p
 			ImportPath: p.ImportPath + ".test",
 			Root:       p.Root,
 			Imports:    str.StringList(TestMainDeps),
+			Module:     p.Module,
 		},
 		Internal: PackageInternal{
 			Build:      &build.Package{Name: "main"},

src/cmd/go/internal/modcmd/download.go

@@ -12,9 +12,8 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
-	"cmd/go/internal/modload"
 	"cmd/go/internal/modfetch"
-	"cmd/go/internal/work"
+	"cmd/go/internal/modload"
 
 	"golang.org/x/mod/module"
 )
@@ -64,7 +63,7 @@ func init() {
 
 	// TODO(jayconrod): https://golang.org/issue/35849 Apply -x to other 'go mod' commands.
 	cmdDownload.Flag.BoolVar(&cfg.BuildX, "x", false, "")
-	work.AddModCommonFlags(cmdDownload)
+	base.AddModCommonFlags(&cmdDownload.Flag)
 }
 
 type moduleJSON struct {
@@ -136,9 +135,10 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	var mods []*moduleJSON
 	listU := false
 	listVersions := false
+	listRetractions := false
 	type token struct{}
 	sem := make(chan token, runtime.GOMAXPROCS(0))
-	for _, info := range modload.ListModules(ctx, args, listU, listVersions) {
+	for _, info := range modload.ListModules(ctx, args, listU, listVersions, listRetractions) {
 		if info.Replace != nil {
 			info = info.Replace
 		}
@@ -187,4 +187,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 		}
 		base.ExitIfErrors()
 	}
+
+	// Update go.mod and especially go.sum if needed.
+	modload.WriteGoMod()
 }

src/cmd/go/internal/modcmd/edit.go

@@ -19,7 +19,6 @@ import (
 	"cmd/go/internal/lockedfile"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/modfile"
 	"golang.org/x/mod/module"
@@ -68,9 +67,14 @@ The -dropreplace=old[@v] flag drops a replacement of the given
 module path and version pair. If the @v is omitted, a replacement without
 a version on the left side is dropped.
 
+The -retract=version and -dropretract=version flags add and drop a
+retraction on the given version. The version may be a single version
+like "v1.2.3" or a closed interval like "[v1.1.0-v1.1.9]". Note that
+-retract=version is a no-op if that retraction already exists.
+
 The -require, -droprequire, -exclude, -dropexclude, -replace,
-and -dropreplace editing flags may be repeated, and the changes
+-dropreplace, -retract, and -dropretract editing flags may be repeated,
-are applied in the order given.
+and the changes are applied in the order given.
 
 The -go=version flag sets the expected Go language version.
 
@@ -104,6 +108,15 @@ writing it back to go.mod. The JSON output corresponds to these Go types:
 		New Module
 	}
 
+	type Retract struct {
+		Low       string
+		High      string
+		Rationale string
+	}
+
+Retract entries representing a single version (not an interval) will have
+the "Low" and "High" fields set to the same value.
+
 Note that this only describes the go.mod file itself, not other modules
 referred to indirectly. For the full set of modules available to a build,
 use 'go list -m -json all'.
@@ -137,8 +150,10 @@ func init() {
 	cmdEdit.Flag.Var(flagFunc(flagDropReplace), "dropreplace", "")
 	cmdEdit.Flag.Var(flagFunc(flagReplace), "replace", "")
 	cmdEdit.Flag.Var(flagFunc(flagDropExclude), "dropexclude", "")
+	cmdEdit.Flag.Var(flagFunc(flagRetract), "retract", "")
+	cmdEdit.Flag.Var(flagFunc(flagDropRetract), "dropretract", "")
 
-	work.AddModCommonFlags(cmdEdit)
+	base.AddModCommonFlags(&cmdEdit.Flag)
 	base.AddBuildFlagsNX(&cmdEdit.Flag)
 }
 
@@ -252,12 +267,7 @@ func parsePathVersion(flag, arg string) (path, version string) {
 		base.Fatalf("go mod: -%s=%s: invalid path: %v", flag, arg, err)
 	}
 
-	// We don't call modfile.CheckPathVersion, because that insists
+	if !allowedVersionArg(version) {
-	// on versions being in semver form, but here we want to allow
-	// versions like "master" or "1234abcdef", which the go command will resolve
-	// the next time it runs (or during -fix).
-	// Even so, we need to make sure the version is a valid token.
-	if modfile.MustQuote(version) {
 		base.Fatalf("go mod: -%s=%s: invalid version %q", flag, arg, version)
 	}
 
@@ -289,12 +299,48 @@ func parsePathVersionOptional(adj, arg string, allowDirPath bool) (path, version
 			return path, version, fmt.Errorf("invalid %s path: %v", adj, err)
 		}
 	}
-	if path != arg && modfile.MustQuote(version) {
+	if path != arg && !allowedVersionArg(version) {
 		return path, version, fmt.Errorf("invalid %s version: %q", adj, version)
 	}
 	return path, version, nil
 }
 
+// parseVersionInterval parses a single version like "v1.2.3" or a closed
+// interval like "[v1.2.3,v1.4.5]". Note that a single version has the same
+// representation as an interval with equal upper and lower bounds: both
+// Low and High are set.
+func parseVersionInterval(arg string) (modfile.VersionInterval, error) {
+	if !strings.HasPrefix(arg, "[") {
+		if !allowedVersionArg(arg) {
+			return modfile.VersionInterval{}, fmt.Errorf("invalid version: %q", arg)
+		}
+		return modfile.VersionInterval{Low: arg, High: arg}, nil
+	}
+	if !strings.HasSuffix(arg, "]") {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	s := arg[1 : len(arg)-1]
+	i := strings.Index(s, ",")
+	if i < 0 {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	low := strings.TrimSpace(s[:i])
+	high := strings.TrimSpace(s[i+1:])
+	if !allowedVersionArg(low) || !allowedVersionArg(high) {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	return modfile.VersionInterval{Low: low, High: high}, nil
+}
+
+// allowedVersionArg returns whether a token may be used as a version in go.mod.
+// We don't call modfile.CheckPathVersion, because that insists on versions
+// being in semver form, but here we want to allow versions like "master" or
+// "1234abcdef", which the go command will resolve the next time it runs (or
+// during -fix).  Even so, we need to make sure the version is a valid token.
+func allowedVersionArg(arg string) bool {
+	return !modfile.MustQuote(arg)
+}
+
 // flagRequire implements the -require flag.
 func flagRequire(arg string) {
 	path, version := parsePathVersion("require", arg)
@@ -377,6 +423,32 @@ func flagDropReplace(arg string) {
 	})
 }
 
+// flagRetract implements the -retract flag.
+func flagRetract(arg string) {
+	vi, err := parseVersionInterval(arg)
+	if err != nil {
+		base.Fatalf("go mod: -retract=%s: %v", arg, err)
+	}
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.AddRetract(vi, ""); err != nil {
+			base.Fatalf("go mod: -retract=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagDropRetract implements the -dropretract flag.
+func flagDropRetract(arg string) {
+	vi, err := parseVersionInterval(arg)
+	if err != nil {
+		base.Fatalf("go mod: -dropretract=%s: %v", arg, err)
+	}
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.DropRetract(vi); err != nil {
+			base.Fatalf("go mod: -dropretract=%s: %v", arg, err)
+		}
+	})
+}
+
 // fileJSON is the -json output data structure.
 type fileJSON struct {
 	Module  module.Version
@@ -384,6 +456,7 @@ type fileJSON struct {
 	Require []requireJSON
 	Exclude []module.Version
 	Replace []replaceJSON
+	Retract []retractJSON
 }
 
 type requireJSON struct {
@@ -397,6 +470,12 @@ type replaceJSON struct {
 	New module.Version
 }
 
+type retractJSON struct {
+	Low       string `json:",omitempty"`
+	High      string `json:",omitempty"`
+	Rationale string `json:",omitempty"`
+}
+
 // editPrintJSON prints the -json output.
 func editPrintJSON(modFile *modfile.File) {
 	var f fileJSON
@@ -415,6 +494,9 @@ func editPrintJSON(modFile *modfile.File) {
 	for _, r := range modFile.Replace {
 		f.Replace = append(f.Replace, replaceJSON{r.Old, r.New})
 	}
+	for _, r := range modFile.Retract {
+		f.Retract = append(f.Retract, retractJSON{r.Low, r.High, r.Rationale})
+	}
 	data, err := json.MarshalIndent(&f, "", "\t")
 	if err != nil {
 		base.Fatalf("go: internal error: %v", err)

src/cmd/go/internal/modcmd/graph.go

@@ -15,7 +15,6 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 )
@@ -33,7 +32,7 @@ path@version, except for the main module, which has no @version suffix.
 }
 
 func init() {
-	work.AddModCommonFlags(cmdGraph)
+	base.AddModCommonFlags(&cmdGraph.Flag)
 }
 
 func runGraph(ctx context.Context, cmd *base.Command, args []string) {
@@ -48,7 +47,7 @@ func runGraph(ctx context.Context, cmd *base.Command, args []string) {
 			base.Fatalf("go: cannot find main module; see 'go help modules'")
 		}
 	}
-	modload.LoadBuildList(ctx)
+	modload.LoadAllModules(ctx)
 
 	reqs := modload.MinReqs()
 	format := func(m module.Version) string {

src/cmd/go/internal/modcmd/init.go

@@ -9,7 +9,6 @@ package modcmd
 import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 	"context"
 	"os"
 	"strings"
@@ -30,7 +29,7 @@ To override this guess, supply the module path as an argument.
 }
 
 func init() {
-	work.AddModCommonFlags(cmdInit)
+	base.AddModCommonFlags(&cmdInit.Flag)
 }
 
 func runInit(ctx context.Context, cmd *base.Command, args []string) {

src/cmd/go/internal/modcmd/tidy.go

@@ -10,7 +10,6 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 	"context"
 )
 
@@ -32,7 +31,7 @@ to standard error.
 func init() {
 	cmdTidy.Run = runTidy // break init cycle
 	cmdTidy.Flag.BoolVar(&cfg.BuildV, "v", false, "")
-	work.AddModCommonFlags(cmdTidy)
+	base.AddModCommonFlags(&cmdTidy.Flag)
 }
 
 func runTidy(ctx context.Context, cmd *base.Command, args []string) {
@@ -40,6 +39,18 @@ func runTidy(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go mod tidy: no arguments allowed")
 	}
 
+	// Tidy aims to make 'go test' reproducible for any package in 'all', so we
+	// need to include test dependencies. For modules that specify go 1.15 or
+	// earlier this is a no-op (because 'all' saturates transitive test
+	// dependencies).
+	//
+	// However, with lazy loading (go 1.16+) 'all' includes only the packages that
+	// are transitively imported by the main module, not the test dependencies of
+	// those packages. In order to make 'go test' reproducible for the packages
+	// that are in 'all' but outside of the main module, we must explicitly
+	// request that their test dependencies be included.
+	modload.LoadTests = true
+
 	modload.LoadALL(ctx)
 	modload.TidyBuildList()
 	modload.TrimGoSum()

src/cmd/go/internal/modcmd/vendor.go

@@ -19,7 +19,6 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/imports"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 	"golang.org/x/mod/semver"
@@ -41,7 +40,7 @@ modules and packages to standard error.
 
 func init() {
 	cmdVendor.Flag.BoolVar(&cfg.BuildV, "v", false, "")
-	work.AddModCommonFlags(cmdVendor)
+	base.AddModCommonFlags(&cmdVendor.Flag)
 }
 
 func runVendor(ctx context.Context, cmd *base.Command, args []string) {
@@ -77,7 +76,7 @@ func runVendor(ctx context.Context, cmd *base.Command, args []string) {
 	}
 
 	var buf bytes.Buffer
-	for _, m := range modload.BuildList()[1:] {
+	for _, m := range modload.LoadedModules()[1:] {
 		if pkgs := modpkgs[m]; len(pkgs) > 0 || isExplicit[m] {
 			line := moduleLine(m, modload.Replacement(m))
 			buf.WriteString(line)

src/cmd/go/internal/modcmd/verify.go

@@ -17,7 +17,6 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 	"golang.org/x/mod/sumdb/dirhash"
@@ -38,7 +37,7 @@ non-zero status.
 }
 
 func init() {
-	work.AddModCommonFlags(cmdVerify)
+	base.AddModCommonFlags(&cmdVerify.Flag)
 }
 
 func runVerify(ctx context.Context, cmd *base.Command, args []string) {
@@ -60,7 +59,7 @@ func runVerify(ctx context.Context, cmd *base.Command, args []string) {
 	sem := make(chan token, runtime.GOMAXPROCS(0))
 
 	// Use a slice of result channels, so that the output is deterministic.
-	mods := modload.LoadBuildList(ctx)[1:]
+	mods := modload.LoadAllModules(ctx)[1:]
 	errsChans := make([]<-chan []error, len(mods))
 
 	for i, mod := range mods {

src/cmd/go/internal/modcmd/why.go

@@ -11,7 +11,6 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 )
@@ -58,23 +57,26 @@ var (
 
 func init() {
 	cmdWhy.Run = runWhy // break init cycle
-	work.AddModCommonFlags(cmdWhy)
+	base.AddModCommonFlags(&cmdWhy.Flag)
 }
 
 func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 	loadALL := modload.LoadALL
 	if *whyVendor {
 		loadALL = modload.LoadVendor
+	} else {
+		modload.LoadTests = true
 	}
 	if *whyM {
 		listU := false
 		listVersions := false
+		listRetractions := false
 		for _, arg := range args {
 			if strings.Contains(arg, "@") {
 				base.Fatalf("go mod why: module query not allowed")
 			}
 		}
-		mods := modload.ListModules(ctx, args, listU, listVersions)
+		mods := modload.ListModules(ctx, args, listU, listVersions, listRetractions)
 		byModule := make(map[module.Version][]string)
 		for _, path := range loadALL(ctx) {
 			m := modload.PackageModule(path)

src/cmd/go/internal/modfetch/fetch.go

@@ -503,6 +503,9 @@ func checkGoMod(path, version string, data []byte) error {
 }
 
 // checkModSum checks that the recorded checksum for mod is h.
+//
+// mod.Version may have the additional suffix "/go.mod" to request the checksum
+// for the module's go.mod file only.
 func checkModSum(mod module.Version, h string) error {
 	// We lock goSum when manipulating it,
 	// but we arrange to release the lock when calling checkSumDB,
@@ -579,9 +582,16 @@ func addModSumLocked(mod module.Version, h string) {
 // checkSumDB checks the mod, h pair against the Go checksum database.
 // It calls base.Fatalf if the hash is to be rejected.
 func checkSumDB(mod module.Version, h string) error {
+	modWithoutSuffix := mod
+	noun := "module"
+	if strings.HasSuffix(mod.Version, "/go.mod") {
+		noun = "go.mod"
+		modWithoutSuffix.Version = strings.TrimSuffix(mod.Version, "/go.mod")
+	}
+
 	db, lines, err := lookupSumDB(mod)
 	if err != nil {
-		return module.VersionError(mod, fmt.Errorf("verifying module: %v", err))
+		return module.VersionError(modWithoutSuffix, fmt.Errorf("verifying %s: %v", noun, err))
 	}
 
 	have := mod.Path + " " + mod.Version + " " + h
@@ -591,7 +601,7 @@ func checkSumDB(mod module.Version, h string) error {
 			return nil
 		}
 		if strings.HasPrefix(line, prefix) {
-			return module.VersionError(mod, fmt.Errorf("verifying module: checksum mismatch\n\tdownloaded: %v\n\t%s: %v"+sumdbMismatch, h, db, line[len(prefix)-len("h1:"):]))
+			return module.VersionError(modWithoutSuffix, fmt.Errorf("verifying %s: checksum mismatch\n\tdownloaded: %v\n\t%s: %v"+sumdbMismatch, noun, h, db, line[len(prefix)-len("h1:"):]))
 		}
 	}
 	return nil

src/cmd/go/internal/modget/get.go

@@ -278,7 +278,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	}
 	modload.LoadTests = *getT
 
-	buildList := modload.LoadBuildList(ctx)
+	buildList := modload.LoadAllModules(ctx)
 	buildList = buildList[:len(buildList):len(buildList)] // copy on append
 	versionByPath := make(map[string]string)
 	for _, m := range buildList {
@@ -290,7 +290,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	// what was requested.
 	modload.DisallowWriteGoMod()
 
-	// Allow looking up modules for import paths outside of a module.
+	// Allow looking up modules for import paths when outside of a module.
 	// 'go get' is expected to do this, unlike other commands.
 	modload.AllowMissingModuleImports()
 
@@ -599,7 +599,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 		base.ExitIfErrors()
 
 		// Stop if no changes have been made to the build list.
-		buildList = modload.BuildList()
+		buildList = modload.LoadedModules()
 		eq := len(buildList) == len(prevBuildList)
 		for i := 0; eq && i < len(buildList); i++ {
 			eq = buildList[i] == prevBuildList[i]
@@ -617,7 +617,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 
 	// Handle downgrades.
 	var down []module.Version
-	for _, m := range modload.BuildList() {
+	for _, m := range modload.LoadedModules() {
 		q := byPath[m.Path]
 		if q != nil && semver.Compare(m.Version, q.m.Version) > 0 {
 			down = append(down, module.Version{Path: m.Path, Version: q.m.Version})
@@ -628,6 +628,10 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 		if err != nil {
 			base.Fatalf("go: %v", err)
 		}
+
+		// TODO(bcmills) What should happen here under lazy loading?
+		// Downgrading may intentionally violate the lazy-loading invariants.
+
 		modload.SetBuildList(buildList)
 		modload.ReloadBuildList() // note: does not update go.mod
 		base.ExitIfErrors()
@@ -637,7 +641,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	var lostUpgrades []*query
 	if len(down) > 0 {
 		versionByPath = make(map[string]string)
-		for _, m := range modload.BuildList() {
+		for _, m := range modload.LoadedModules() {
 			versionByPath[m.Path] = m.Version
 		}
 		for _, q := range byPath {
@@ -702,6 +706,15 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	// Everything succeeded. Update go.mod.
 	modload.AllowWriteGoMod()
 	modload.WriteGoMod()
+	modload.DisallowWriteGoMod()
+
+	// Report warnings if any retracted versions are in the build list.
+	// This must be done after writing go.mod to avoid spurious '// indirect'
+	// comments. These functions read and write global state.
+	// TODO(golang.org/issue/40775): ListModules resets modload.loader, which
+	// contains information about direct dependencies that WriteGoMod uses.
+	// Refactor to avoid these kinds of global side effects.
+	reportRetractions(ctx)
 
 	// If -d was specified, we're done after the module work.
 	// We've already downloaded modules by loading packages above.
@@ -804,6 +817,14 @@ func getQuery(ctx context.Context, path, vers string, prevM module.Version, forc
 		base.Fatalf("go get: internal error: prevM may be set if and only if forceModulePath is set")
 	}
 
+	// If vers is a query like "latest", we should ignore retracted and excluded
+	// versions. If vers refers to a specific version or commit like "v1.0.0"
+	// or "master", we should only ignore excluded versions.
+	allowed := modload.CheckAllowed
+	if modload.IsRevisionQuery(vers) {
+		allowed = modload.CheckExclusions
+	}
+
 	// If the query must be a module path, try only that module path.
 	if forceModulePath {
 		if path == modload.Target.Path {
@@ -812,7 +833,7 @@ func getQuery(ctx context.Context, path, vers string, prevM module.Version, forc
 			}
 		}
 
-		info, err := modload.Query(ctx, path, vers, prevM.Version, modload.Allowed)
+		info, err := modload.Query(ctx, path, vers, prevM.Version, allowed)
 		if err == nil {
 			if info.Version != vers && info.Version != prevM.Version {
 				logOncef("go: %s %s => %s", path, vers, info.Version)
@@ -838,7 +859,7 @@ func getQuery(ctx context.Context, path, vers string, prevM module.Version, forc
 	// If it turns out to only exist as a module, we can detect the resulting
 	// PackageNotInModuleError and avoid a second round-trip through (potentially)
 	// all of the configured proxies.
-	results, err := modload.QueryPattern(ctx, path, vers, modload.Allowed)
+	results, err := modload.QueryPattern(ctx, path, vers, allowed)
 	if err != nil {
 		// If the path doesn't contain a wildcard, check whether it was actually a
 		// module path instead. If so, return that.
@@ -864,190 +885,41 @@ func getQuery(ctx context.Context, path, vers string, prevM module.Version, forc
 	return m, nil
 }
 
-// An upgrader adapts an underlying mvs.Reqs to apply an
+// reportRetractions prints warnings if any modules in the build list are
-// upgrade policy to a list of targets and their dependencies.
+// retracted.
-type upgrader struct {
+func reportRetractions(ctx context.Context) {
-	mvs.Reqs
+	// Query for retractions of modules in the build list.
-
+	// Use modload.ListModules, since that provides information in the same format
-	// cmdline maps a module path to a query made for that module at a
+	// as 'go list -m'. Don't query for "all", since that's not allowed outside a
-	// specific target version. Each query corresponds to a module
+	// module.
-	// matched by a command line argument.
+	buildList := modload.LoadedModules()
-	cmdline map[string]*query
+	args := make([]string, 0, len(buildList))
-
+	for _, m := range buildList {
-	// upgrade is a set of modules providing dependencies of packages
+		if m.Version == "" {
-	// matched by command line arguments. If -u or -u=patch is set,
+			// main module or dummy target module
-	// these modules are upgraded accordingly.
+			continue
-	upgrade map[string]bool
+		}
-}
+		args = append(args, m.Path+"@"+m.Version)
-
-// newUpgrader creates an upgrader. cmdline contains queries made at
-// specific versions for modules matched by command line arguments. pkgs
-// is the set of packages matched by command line arguments. If -u or -u=patch
-// is set, modules providing dependencies of pkgs are upgraded accordingly.
-func newUpgrader(cmdline map[string]*query, pkgs map[string]bool) *upgrader {
-	u := &upgrader{
-		Reqs:    modload.Reqs(),
-		cmdline: cmdline,
 	}
-	if getU != "" {
+	listU := false
-		u.upgrade = make(map[string]bool)
+	listVersions := false
-
+	listRetractions := true
-		// Traverse package import graph.
+	mods := modload.ListModules(ctx, args, listU, listVersions, listRetractions)
-		// Initialize work queue with root packages.
+	retractPath := ""
-		seen := make(map[string]bool)
+	for _, mod := range mods {
-		var work []string
+		if len(mod.Retracted) > 0 {
-		add := func(path string) {
+			if retractPath == "" {
-			if !seen[path] {
+				retractPath = mod.Path
-				seen[path] = true
+			} else {
-				work = append(work, path)
+				retractPath = "<module>"
-			}
-		}
-		for pkg := range pkgs {
-			add(pkg)
-		}
-		for len(work) > 0 {
-			pkg := work[0]
-			work = work[1:]
-			m := modload.PackageModule(pkg)
-			u.upgrade[m.Path] = true
-
-			// testImports is empty unless test imports were actually loaded,
-			// i.e., -t was set or "all" was one of the arguments.
-			imports, testImports := modload.PackageImports(pkg)
-			for _, imp := range imports {
-				add(imp)
-			}
-			for _, imp := range testImports {
-				add(imp)
 			}
+			rationale := modload.ShortRetractionRationale(mod.Retracted[0])
+			logOncef("go: warning: %s@%s is retracted: %s", mod.Path, mod.Version, rationale)
 		}
 	}
-	return u
+	if modload.HasModRoot() && retractPath != "" {
-}
+		logOncef("go: run 'go get %s@latest' to switch to the latest unretracted version", retractPath)
-
-// Required returns the requirement list for m.
-// For the main module, we override requirements with the modules named
-// one the command line, and we include new requirements. Otherwise,
-// we defer to u.Reqs.
-func (u *upgrader) Required(m module.Version) ([]module.Version, error) {
-	rs, err := u.Reqs.Required(m)
-	if err != nil {
-		return nil, err
 	}
-	if m != modload.Target {
-		return rs, nil
-	}
-
-	overridden := make(map[string]bool)
-	for i, m := range rs {
-		if q := u.cmdline[m.Path]; q != nil && q.m.Version != "none" {
-			rs[i] = q.m
-			overridden[q.m.Path] = true
-		}
-	}
-	for _, q := range u.cmdline {
-		if !overridden[q.m.Path] && q.m.Path != modload.Target.Path && q.m.Version != "none" {
-			rs = append(rs, q.m)
-		}
-	}
-	return rs, nil
-}
-
-// Upgrade returns the desired upgrade for m.
-//
-// If m was requested at a specific version on the command line, then
-// Upgrade returns that version.
-//
-// If -u is set and m provides a dependency of a package matched by
-// command line arguments, then Upgrade may provider a newer tagged version.
-// If m is a tagged version, then Upgrade will return the latest tagged
-// version (with the same minor version number if -u=patch).
-// If m is a pseudo-version, then Upgrade returns the latest tagged version
-// only if that version has a time-stamp newer than m. This special case
-// prevents accidental downgrades when already using a pseudo-version
-// newer than the latest tagged version.
-//
-// If none of the above cases apply, then Upgrade returns m.
-func (u *upgrader) Upgrade(m module.Version) (module.Version, error) {
-	// Allow pkg@vers on the command line to override the upgrade choice v.
-	// If q's version is < m.Version, then we're going to downgrade anyway,
-	// and it's cleaner to avoid moving back and forth and picking up
-	// extraneous other newer dependencies.
-	// If q's version is > m.Version, then we're going to upgrade past
-	// m.Version anyway, and again it's cleaner to avoid moving back and forth
-	// picking up extraneous other newer dependencies.
-	if q := u.cmdline[m.Path]; q != nil {
-		return q.m, nil
-	}
-
-	if !u.upgrade[m.Path] {
-		// Not involved in upgrade. Leave alone.
-		return m, nil
-	}
-
-	// Run query required by upgrade semantics.
-	// Note that Query "latest" is not the same as using repo.Latest,
-	// which may return a pseudoversion for the latest commit.
-	// Query "latest" returns the newest tagged version or the newest
-	// prerelease version if there are no non-prereleases, or repo.Latest
-	// if there aren't any tagged versions.
-	// If we're querying "upgrade" or "patch", Query will compare the current
-	// version against the chosen version and will return the current version
-	// if it is newer.
-	info, err := modload.Query(context.TODO(), m.Path, string(getU), m.Version, modload.Allowed)
-	if err != nil {
-		// Report error but return m, to let version selection continue.
-		// (Reporting the error will fail the command at the next base.ExitIfErrors.)
-
-		// Special case: if the error is for m.Version itself and m.Version has a
-		// replacement, then keep it and don't report the error: the fact that the
-		// version is invalid is likely the reason it was replaced to begin with.
-		var vErr *module.InvalidVersionError
-		if errors.As(err, &vErr) && vErr.Version == m.Version && modload.Replacement(m).Path != "" {
-			return m, nil
-		}
-
-		// Special case: if the error is "no matching versions" then don't
-		// even report the error. Because Query does not consider pseudo-versions,
-		// it may happen that we have a pseudo-version but during -u=patch
-		// the query v0.0 matches no versions (not even the one we're using).
-		var noMatch *modload.NoMatchingVersionError
-		if !errors.As(err, &noMatch) {
-			base.Errorf("go get: upgrading %s@%s: %v", m.Path, m.Version, err)
-		}
-		return m, nil
-	}
-
-	if info.Version != m.Version {
-		logOncef("go: %s %s => %s", m.Path, getU, info.Version)
-	}
-	return module.Version{Path: m.Path, Version: info.Version}, nil
-}
-
-// buildListForLostUpgrade returns the build list for the module graph
-// rooted at lost. Unlike mvs.BuildList, the target module (lost) is not
-// treated specially. The returned build list may contain a newer version
-// of lost.
-//
-// buildListForLostUpgrade is used after a downgrade has removed a module
-// requested at a specific version. This helps us understand the requirements
-// implied by each downgrade.
-func buildListForLostUpgrade(lost module.Version, reqs mvs.Reqs) ([]module.Version, error) {
-	return mvs.BuildList(lostUpgradeRoot, &lostUpgradeReqs{Reqs: reqs, lost: lost})
-}
-
-var lostUpgradeRoot = module.Version{Path: "lost-upgrade-root", Version: ""}
-
-type lostUpgradeReqs struct {
-	mvs.Reqs
-	lost module.Version
-}
-
-func (r *lostUpgradeReqs) Required(mod module.Version) ([]module.Version, error) {
-	if mod == lostUpgradeRoot {
-		return []module.Version{r.lost}, nil
-	}
-	return r.Reqs.Required(mod)
 }
 
 var loggedLines sync.Map

src/cmd/go/internal/modget/mvs.go

@@ -0,0 +1,202 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modget
+
+import (
+	"context"
+	"errors"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/modload"
+	"cmd/go/internal/mvs"
+
+	"golang.org/x/mod/module"
+)
+
+// An upgrader adapts an underlying mvs.Reqs to apply an
+// upgrade policy to a list of targets and their dependencies.
+type upgrader struct {
+	mvs.Reqs
+
+	// cmdline maps a module path to a query made for that module at a
+	// specific target version. Each query corresponds to a module
+	// matched by a command line argument.
+	cmdline map[string]*query
+
+	// upgrade is a set of modules providing dependencies of packages
+	// matched by command line arguments. If -u or -u=patch is set,
+	// these modules are upgraded accordingly.
+	upgrade map[string]bool
+}
+
+// newUpgrader creates an upgrader. cmdline contains queries made at
+// specific versions for modules matched by command line arguments. pkgs
+// is the set of packages matched by command line arguments. If -u or -u=patch
+// is set, modules providing dependencies of pkgs are upgraded accordingly.
+func newUpgrader(cmdline map[string]*query, pkgs map[string]bool) *upgrader {
+	u := &upgrader{
+		Reqs:    modload.Reqs(),
+		cmdline: cmdline,
+	}
+	if getU != "" {
+		u.upgrade = make(map[string]bool)
+
+		// Traverse package import graph.
+		// Initialize work queue with root packages.
+		seen := make(map[string]bool)
+		var work []string
+		add := func(path string) {
+			if !seen[path] {
+				seen[path] = true
+				work = append(work, path)
+			}
+		}
+		for pkg := range pkgs {
+			add(pkg)
+		}
+		for len(work) > 0 {
+			pkg := work[0]
+			work = work[1:]
+			m := modload.PackageModule(pkg)
+			u.upgrade[m.Path] = true
+
+			// testImports is empty unless test imports were actually loaded,
+			// i.e., -t was set or "all" was one of the arguments.
+			imports, testImports := modload.PackageImports(pkg)
+			for _, imp := range imports {
+				add(imp)
+			}
+			for _, imp := range testImports {
+				add(imp)
+			}
+		}
+	}
+	return u
+}
+
+// Required returns the requirement list for m.
+// For the main module, we override requirements with the modules named
+// one the command line, and we include new requirements. Otherwise,
+// we defer to u.Reqs.
+func (u *upgrader) Required(m module.Version) ([]module.Version, error) {
+	rs, err := u.Reqs.Required(m)
+	if err != nil {
+		return nil, err
+	}
+	if m != modload.Target {
+		return rs, nil
+	}
+
+	overridden := make(map[string]bool)
+	for i, m := range rs {
+		if q := u.cmdline[m.Path]; q != nil && q.m.Version != "none" {
+			rs[i] = q.m
+			overridden[q.m.Path] = true
+		}
+	}
+	for _, q := range u.cmdline {
+		if !overridden[q.m.Path] && q.m.Path != modload.Target.Path && q.m.Version != "none" {
+			rs = append(rs, q.m)
+		}
+	}
+	return rs, nil
+}
+
+// Upgrade returns the desired upgrade for m.
+//
+// If m was requested at a specific version on the command line, then
+// Upgrade returns that version.
+//
+// If -u is set and m provides a dependency of a package matched by
+// command line arguments, then Upgrade may provider a newer tagged version.
+// If m is a tagged version, then Upgrade will return the latest tagged
+// version (with the same minor version number if -u=patch).
+// If m is a pseudo-version, then Upgrade returns the latest tagged version
+// only if that version has a time-stamp newer than m. This special case
+// prevents accidental downgrades when already using a pseudo-version
+// newer than the latest tagged version.
+//
+// If none of the above cases apply, then Upgrade returns m.
+func (u *upgrader) Upgrade(m module.Version) (module.Version, error) {
+	// Allow pkg@vers on the command line to override the upgrade choice v.
+	// If q's version is < m.Version, then we're going to downgrade anyway,
+	// and it's cleaner to avoid moving back and forth and picking up
+	// extraneous other newer dependencies.
+	// If q's version is > m.Version, then we're going to upgrade past
+	// m.Version anyway, and again it's cleaner to avoid moving back and forth
+	// picking up extraneous other newer dependencies.
+	if q := u.cmdline[m.Path]; q != nil {
+		return q.m, nil
+	}
+
+	if !u.upgrade[m.Path] {
+		// Not involved in upgrade. Leave alone.
+		return m, nil
+	}
+
+	// Run query required by upgrade semantics.
+	// Note that Query "latest" is not the same as using repo.Latest,
+	// which may return a pseudoversion for the latest commit.
+	// Query "latest" returns the newest tagged version or the newest
+	// prerelease version if there are no non-prereleases, or repo.Latest
+	// if there aren't any tagged versions.
+	// If we're querying "upgrade" or "patch", Query will compare the current
+	// version against the chosen version and will return the current version
+	// if it is newer.
+	info, err := modload.Query(context.TODO(), m.Path, string(getU), m.Version, modload.CheckAllowed)
+	if err != nil {
+		// Report error but return m, to let version selection continue.
+		// (Reporting the error will fail the command at the next base.ExitIfErrors.)
+
+		// Special case: if the error is for m.Version itself and m.Version has a
+		// replacement, then keep it and don't report the error: the fact that the
+		// version is invalid is likely the reason it was replaced to begin with.
+		var vErr *module.InvalidVersionError
+		if errors.As(err, &vErr) && vErr.Version == m.Version && modload.Replacement(m).Path != "" {
+			return m, nil
+		}
+
+		// Special case: if the error is "no matching versions" then don't
+		// even report the error. Because Query does not consider pseudo-versions,
+		// it may happen that we have a pseudo-version but during -u=patch
+		// the query v0.0 matches no versions (not even the one we're using).
+		var noMatch *modload.NoMatchingVersionError
+		if !errors.As(err, &noMatch) {
+			base.Errorf("go get: upgrading %s@%s: %v", m.Path, m.Version, err)
+		}
+		return m, nil
+	}
+
+	if info.Version != m.Version {
+		logOncef("go: %s %s => %s", m.Path, getU, info.Version)
+	}
+	return module.Version{Path: m.Path, Version: info.Version}, nil
+}
+
+// buildListForLostUpgrade returns the build list for the module graph
+// rooted at lost. Unlike mvs.BuildList, the target module (lost) is not
+// treated specially. The returned build list may contain a newer version
+// of lost.
+//
+// buildListForLostUpgrade is used after a downgrade has removed a module
+// requested at a specific version. This helps us understand the requirements
+// implied by each downgrade.
+func buildListForLostUpgrade(lost module.Version, reqs mvs.Reqs) ([]module.Version, error) {
+	return mvs.BuildList(lostUpgradeRoot, &lostUpgradeReqs{Reqs: reqs, lost: lost})
+}
+
+var lostUpgradeRoot = module.Version{Path: "lost-upgrade-root", Version: ""}
+
+type lostUpgradeReqs struct {
+	mvs.Reqs
+	lost module.Version
+}
+
+func (r *lostUpgradeReqs) Required(mod module.Version) ([]module.Version, error) {
+	if mod == lostUpgradeRoot {
+		return []module.Version{r.lost}, nil
+	}
+	return r.Reqs.Required(mod)
+}