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cmd/internal/gc, cmd/6g: generate boolean values without jumps
Use SETcc instructions instead of Jcc to generate boolean values.
This generates shorter, jump-free code, which may in turn enable other
peephole optimizations.
For example, given
func f(i, j int) bool {
return i == j
}
Before
"".f t=1 size=32 value=0 args=0x18 locals=0x0
0x0000 00000 (x.go:3) TEXT "".f(SB), $0-24
0x0000 00000 (x.go:3) FUNCDATA $0, gclocals·b4c25e9b09fd0cf9bb429dcefe91c353(SB)
0x0000 00000 (x.go:3) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
0x0000 00000 (x.go:4) MOVQ "".i+8(FP), BX
0x0005 00005 (x.go:4) MOVQ "".j+16(FP), BP
0x000a 00010 (x.go:4) CMPQ BX, BP
0x000d 00013 (x.go:4) JEQ 21
0x000f 00015 (x.go:4) MOVB $0, "".~r2+24(FP)
0x0014 00020 (x.go:4) RET
0x0015 00021 (x.go:4) MOVB $1, "".~r2+24(FP)
0x001a 00026 (x.go:4) JMP 20
After
"".f t=1 size=32 value=0 args=0x18 locals=0x0
0x0000 00000 (x.go:3) TEXT "".f(SB), $0-24
0x0000 00000 (x.go:3) FUNCDATA $0, gclocals·b4c25e9b09fd0cf9bb429dcefe91c353(SB)
0x0000 00000 (x.go:3) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
0x0000 00000 (x.go:4) MOVQ "".i+8(FP), BX
0x0005 00005 (x.go:4) MOVQ "".j+16(FP), BP
0x000a 00010 (x.go:4) CMPQ BX, BP
0x000d 00013 (x.go:4) SETEQ "".~r2+24(FP)
0x0012 00018 (x.go:4) RET
regexp benchmarks, best of 12 runs:
benchmark old ns/op new ns/op delta
BenchmarkNotOnePassShortB 782 733 -6.27%
BenchmarkLiteral 180 171 -5.00%
BenchmarkNotLiteral 2855 2721 -4.69%
BenchmarkMatchHard_32 2672 2557 -4.30%
BenchmarkMatchHard_1K 80182 76732 -4.30%
BenchmarkMatchEasy1_32M 76440180 73304748 -4.10%
BenchmarkMatchEasy1_32K 68798 66350 -3.56%
BenchmarkAnchoredLongMatch 482 465 -3.53%
BenchmarkMatchEasy1_1M 2373042 2292692 -3.39%
BenchmarkReplaceAll 2776 2690 -3.10%
BenchmarkNotOnePassShortA 1397 1360 -2.65%
BenchmarkMatchClass_InRange 3842 3742 -2.60%
BenchmarkMatchEasy0_32 125 122 -2.40%
BenchmarkMatchEasy0_32K 11414 11164 -2.19%
BenchmarkMatchEasy0_1K 668 654 -2.10%
BenchmarkAnchoredShortMatch 260 255 -1.92%
BenchmarkAnchoredLiteralShortNonMatch 164 161 -1.83%
BenchmarkOnePassShortB 623 612 -1.77%
BenchmarkOnePassShortA 801 788 -1.62%
BenchmarkMatchClass 4094 4033 -1.49%
BenchmarkMatchEasy0_32M 14078800 13890704 -1.34%
BenchmarkMatchHard_32K 4095844 4045820 -1.22%
BenchmarkMatchEasy1_1K 1663 1643 -1.20%
BenchmarkMatchHard_1M 131261708 129708215 -1.18%
BenchmarkMatchHard_32M 4210112412 4169292003 -0.97%
BenchmarkMatchMedium_32K 2460752 2438611 -0.90%
BenchmarkMatchEasy0_1M 422914 419672 -0.77%
BenchmarkMatchMedium_1M 78581121 78040160 -0.69%
BenchmarkMatchMedium_32M 2515287278 2498464906 -0.67%
BenchmarkMatchMedium_32 1754 1746 -0.46%
BenchmarkMatchMedium_1K 52105 52106 +0.00%
BenchmarkAnchoredLiteralLongNonMatch 185 185 +0.00%
BenchmarkMatchEasy1_32 107 107 +0.00%
BenchmarkOnePassLongNotPrefix 505 505 +0.00%
BenchmarkOnePassLongPrefix 147 147 +0.00%
The godoc binary is ~0.12% smaller after this CL.
Updates #5729.
toolstash -cmp passes for all architectures other than amd64 and amd64p32.
Other architectures can be done in follow-up CLs.
Change-Id: I0e167e259274b722958567fc0af83a17ca002da7
Reviewed-on: https://go-review.googlesource.com/2284
Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Josh Bleecher Snyder
parent
9c1868d06d
commit
13cb62c764
7 changed files with 286 additions and 55 deletions
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@ -345,20 +345,12 @@ func Cgen(n *Node, res *Node) {
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Dump("cgen-res", res)
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Fatal("cgen: unknown op %v", Nconv(n, obj.FmtShort|obj.FmtSign))
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// these call bgen to get a bool value
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case OOROR, OANDAND,
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OEQ, ONE,
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OLT, OLE,
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OGE, OGT,
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ONOT:
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p1 := Gbranch(obj.AJMP, nil, 0)
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p2 := Pc
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Thearch.Gmove(Nodbool(true), res)
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p3 := Gbranch(obj.AJMP, nil, 0)
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Patch(p1, Pc)
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Bgen(n, true, 0, p2)
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Thearch.Gmove(Nodbool(false), res)
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Patch(p3, Pc)
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Bvgen(n, res, true)
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return
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case OPLUS:
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@ -1640,10 +1632,55 @@ func Igen(n *Node, a *Node, res *Node) {
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// goto to
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// }
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func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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if Debug['g'] != 0 {
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fmt.Printf("\nbgen wantTrue=%t likely=%d to=%v\n", wantTrue, likely, to)
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Dump("bgen", n)
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bgenx(n, nil, wantTrue, likely, to)
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}
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// Bvgen generates code for calculating boolean values:
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// res = n == wantTrue
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func Bvgen(n, res *Node, wantTrue bool) {
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if Thearch.Ginsboolval == nil {
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// Direct value generation not implemented for this architecture.
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// Implement using jumps.
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bvgenjump(n, res, wantTrue, true)
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return
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}
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bgenx(n, res, wantTrue, 0, nil)
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}
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// bvgenjump implements boolean value generation using jumps:
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// if n == wantTrue {
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// res = 1
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// } else {
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// res = 0
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// }
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// geninit controls whether n's Ninit is generated.
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func bvgenjump(n, res *Node, wantTrue, geninit bool) {
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init := n.Ninit
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if !geninit {
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n.Ninit = nil
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}
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p1 := Gbranch(obj.AJMP, nil, 0)
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p2 := Pc
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Thearch.Gmove(Nodbool(true), res)
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p3 := Gbranch(obj.AJMP, nil, 0)
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Patch(p1, Pc)
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Bgen(n, wantTrue, 0, p2)
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Thearch.Gmove(Nodbool(false), res)
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Patch(p3, Pc)
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n.Ninit = init
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}
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// bgenx is the backend for Bgen and Bvgen.
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// If res is nil, it generates a branch.
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// Otherwise, it generates a boolean value.
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func bgenx(n, res *Node, wantTrue bool, likely int, to *obj.Prog) {
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if Debug['g'] != 0 {
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fmt.Printf("\nbgenx wantTrue=%t likely=%d to=%v\n", wantTrue, likely, to)
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Dump("n", n)
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Dump("res", res)
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}
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genval := res != nil
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if n == nil {
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n = Nodbool(true)
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@ -1659,9 +1696,7 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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}
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if n.Type.Etype != TBOOL {
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Yyerror("cgen: bad type %v for %v", n.Type, Oconv(int(n.Op), 0))
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Patch(Thearch.Gins(obj.AEND, nil, nil), to)
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return
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Fatal("bgen: bad type %v for %v", n.Type, Oconv(int(n.Op), 0))
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}
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for n.Op == OCONVNOP {
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@ -1670,44 +1705,90 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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}
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if Thearch.Bgen_float != nil && n.Left != nil && Isfloat[n.Left.Type.Etype] {
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if genval {
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bvgenjump(n, res, wantTrue, false)
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return
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}
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Thearch.Bgen_float(n, wantTrue, likely, to)
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return
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}
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switch n.Op {
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default:
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if genval {
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Cgen(n, res)
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if !wantTrue {
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Thearch.Gins(Thearch.Optoas(OXOR, Types[TUINT8]), Nodintconst(1), res)
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}
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return
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}
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var tmp Node
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Regalloc(&tmp, n.Type, nil)
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Cgen(n, &tmp)
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bgenNonZero(&tmp, wantTrue, likely, to)
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bgenNonZero(&tmp, nil, wantTrue, likely, to)
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Regfree(&tmp)
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return
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case ONAME:
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if genval {
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// 5g, 7g, and 9g might need a temporary or other help here,
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// but they don't support direct generation of a bool value yet.
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// We can fix that as we go.
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switch Ctxt.Arch.Thechar {
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case '5', '7', '9':
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Fatal("genval 5g, 7g, 9g ONAMES not fully implemented")
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}
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Cgen(n, res)
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if !wantTrue {
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Thearch.Gins(Thearch.Optoas(OXOR, Types[TUINT8]), Nodintconst(1), res)
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}
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return
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}
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if n.Addable && Ctxt.Arch.Thechar != '5' && Ctxt.Arch.Thechar != '7' && Ctxt.Arch.Thechar != '9' {
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// no need for a temporary
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bgenNonZero(n, wantTrue, likely, to)
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bgenNonZero(n, nil, wantTrue, likely, to)
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return
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}
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var tmp Node
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Regalloc(&tmp, n.Type, nil)
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Cgen(n, &tmp)
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bgenNonZero(&tmp, wantTrue, likely, to)
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bgenNonZero(&tmp, nil, wantTrue, likely, to)
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Regfree(&tmp)
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return
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case OLITERAL:
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// n is a constant. If n == wantTrue, jump; otherwise do nothing.
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// n is a constant.
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if !Isconst(n, CTBOOL) {
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Fatal("bgen: non-bool const %v\n", Nconv(n, obj.FmtLong))
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}
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if genval {
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Cgen(Nodbool(wantTrue == n.Val.U.Bval), res)
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return
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}
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// If n == wantTrue, jump; otherwise do nothing.
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if wantTrue == n.Val.U.Bval {
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Patch(Gbranch(obj.AJMP, nil, likely), to)
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}
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return
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case OANDAND, OOROR:
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if (n.Op == OANDAND) == wantTrue {
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and := (n.Op == OANDAND) == wantTrue
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if genval {
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p1 := Gbranch(obj.AJMP, nil, 0)
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p2 := Gbranch(obj.AJMP, nil, 0)
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Patch(p2, Pc)
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Cgen(Nodbool(!and), res)
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p3 := Gbranch(obj.AJMP, nil, 0)
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Patch(p1, Pc)
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Bgen(n.Left, wantTrue != and, 0, p2)
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Bvgen(n.Right, res, wantTrue)
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Patch(p3, Pc)
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return
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}
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if and {
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p1 := Gbranch(obj.AJMP, nil, 0)
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p2 := Gbranch(obj.AJMP, nil, 0)
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Patch(p1, Pc)
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@ -1726,7 +1807,7 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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if n.Left == nil || n.Left.Type == nil {
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return
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}
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Bgen(n.Left, !wantTrue, likely, to)
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bgenx(n.Left, res, !wantTrue, likely, to)
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return
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case OEQ, ONE, OLT, OGT, OLE, OGE:
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@ -1743,15 +1824,21 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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if !wantTrue {
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if Isfloat[nr.Type.Etype] {
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// Brcom is not valid on floats when NaN is involved.
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ll := n.Ninit // avoid re-genning Ninit
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n.Ninit = nil
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if genval {
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bgenx(n, res, true, likely, to)
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Thearch.Gins(Thearch.Optoas(OXOR, Types[TUINT8]), Nodintconst(1), res) // res = !res
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n.Ninit = ll
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return
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}
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p1 := Gbranch(obj.AJMP, nil, 0)
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p2 := Gbranch(obj.AJMP, nil, 0)
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Patch(p1, Pc)
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ll := n.Ninit // avoid re-genning Ninit
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n.Ninit = nil
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Bgen(n, true, -likely, p2)
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n.Ninit = ll
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bgenx(n, res, true, -likely, p2)
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Patch(Gbranch(obj.AJMP, nil, 0), to)
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Patch(p2, Pc)
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n.Ninit = ll
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return
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}
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@ -1786,17 +1873,22 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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Regalloc(&tmp, ptr.Type, &ptr)
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Cgen(&ptr, &tmp)
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Regfree(&ptr)
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bgenNonZero(&tmp, a == OEQ != wantTrue, likely, to)
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bgenNonZero(&tmp, res, a == OEQ != wantTrue, likely, to)
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Regfree(&tmp)
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return
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}
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if Iscomplex[nl.Type.Etype] {
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complexbool(a, nl, nr, wantTrue, likely, to)
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complexbool(a, nl, nr, res, wantTrue, likely, to)
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return
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}
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if Ctxt.Arch.Regsize == 4 && Is64(nr.Type) {
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if genval {
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// TODO: Teach Cmp64 to generate boolean values and remove this.
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bvgenjump(n, res, wantTrue, false)
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return
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}
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if !nl.Addable || Isconst(nl, CTINT) {
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nl = CgenTemp(nl)
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}
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@ -1838,7 +1930,7 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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if Smallintconst(nr) && Ctxt.Arch.Thechar != '9' {
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Thearch.Gins(Thearch.Optoas(OCMP, nr.Type), nl, nr)
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Patch(Gbranch(Thearch.Optoas(a, nr.Type), nr.Type, likely), to)
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bins(nr.Type, res, a, likely, to)
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return
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}
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@ -1869,6 +1961,9 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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if Isfloat[nl.Type.Etype] {
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switch Ctxt.Arch.Thechar {
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case '5':
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if genval {
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Fatal("genval 5g Isfloat special cases not implemented")
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}
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switch n.Op {
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case ONE:
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Patch(Gbranch(Thearch.Optoas(OPS, nr.Type), nr.Type, likely), to)
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@ -1883,19 +1978,40 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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switch n.Op {
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case OEQ:
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// neither NE nor P
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p1 := Gbranch(Thearch.Optoas(ONE, nr.Type), nil, -likely)
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p2 := Gbranch(Thearch.Optoas(OPS, nr.Type), nil, -likely)
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Patch(Gbranch(obj.AJMP, nil, 0), to)
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Patch(p1, Pc)
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Patch(p2, Pc)
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if genval {
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var reg Node
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Regalloc(®, Types[TBOOL], nil)
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Thearch.Ginsboolval(Thearch.Optoas(OEQ, nr.Type), ®)
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Thearch.Ginsboolval(Thearch.Optoas(OPC, nr.Type), res)
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Thearch.Gins(Thearch.Optoas(OAND, Types[TBOOL]), ®, res)
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Regfree(®)
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} else {
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p1 := Gbranch(Thearch.Optoas(ONE, nr.Type), nil, -likely)
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p2 := Gbranch(Thearch.Optoas(OPS, nr.Type), nil, -likely)
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Patch(Gbranch(obj.AJMP, nil, 0), to)
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Patch(p1, Pc)
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Patch(p2, Pc)
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}
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return
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case ONE:
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// either NE or P
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Patch(Gbranch(Thearch.Optoas(ONE, nr.Type), nil, likely), to)
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Patch(Gbranch(Thearch.Optoas(OPS, nr.Type), nil, likely), to)
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if genval {
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var reg Node
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Regalloc(®, Types[TBOOL], nil)
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Thearch.Ginsboolval(Thearch.Optoas(ONE, nr.Type), ®)
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Thearch.Ginsboolval(Thearch.Optoas(OPS, nr.Type), res)
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Thearch.Gins(Thearch.Optoas(OOR, Types[TBOOL]), ®, res)
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Regfree(®)
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} else {
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Patch(Gbranch(Thearch.Optoas(ONE, nr.Type), nil, likely), to)
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Patch(Gbranch(Thearch.Optoas(OPS, nr.Type), nil, likely), to)
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}
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return
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}
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case '7', '9':
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if genval {
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Fatal("genval 7g, 9g Isfloat special cases not implemented")
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}
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switch n.Op {
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// On arm64 and ppc64, <= and >= mishandle NaN. Must decompose into < or > and =.
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// TODO(josh): Convert a <= b to b > a instead?
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@ -1912,11 +2028,11 @@ func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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}
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}
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// Not a special case. Insert an appropriate conditional jump.
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Patch(Gbranch(Thearch.Optoas(a, nr.Type), nr.Type, likely), to)
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// Not a special case. Insert the conditional jump or value gen.
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bins(nr.Type, res, a, likely, to)
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}
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func bgenNonZero(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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func bgenNonZero(n, res *Node, wantTrue bool, likely int, to *obj.Prog) {
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// TODO: Optimize on systems that can compare to zero easily.
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a := ONE
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if !wantTrue {
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@ -1925,7 +2041,21 @@ func bgenNonZero(n *Node, wantTrue bool, likely int, to *obj.Prog) {
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var zero Node
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Nodconst(&zero, n.Type, 0)
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Thearch.Gins(Thearch.Optoas(OCMP, n.Type), n, &zero)
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Patch(Gbranch(Thearch.Optoas(a, n.Type), n.Type, likely), to)
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bins(n.Type, res, a, likely, to)
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}
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// bins inserts an instruction to handle the result of a compare.
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// If res is non-nil, it inserts appropriate value generation instructions.
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// If res is nil, it inserts a branch to to.
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func bins(typ *Type, res *Node, a, likely int, to *obj.Prog) {
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a = Thearch.Optoas(a, typ)
|
||||
if res != nil {
|
||||
// value gen
|
||||
Thearch.Ginsboolval(a, res)
|
||||
} else {
|
||||
// jump
|
||||
Patch(Gbranch(a, typ, likely), to)
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue