cmd/compile: make wasm match other platforms for FP->int32/64 conversions

this change is for overflows, so that all the platforms agree.

Change-Id: I9f459353615bf24ef8a5de641063d9ce34986241
Reviewed-on: https://go-review.googlesource.com/c/go/+/708358
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>

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

@@ -76,13 +76,14 @@
 (Cvt32Uto(64|32)F x) => (F(64|32)ConvertI64U (ZeroExt32to64 x))
 (Cvt64Uto(64|32)F ...) => (F(64|32)ConvertI64U ...)
 
-(Cvt32Fto32 ...) => (I64TruncSatF32S ...)
+(Cvt32Fto32 ...) => (I32TruncSatF32S ...)
 (Cvt32Fto64 ...) => (I64TruncSatF32S ...)
-(Cvt64Fto32 ...) => (I64TruncSatF64S ...)
+(Cvt64Fto32 ...) => (I32TruncSatF64S ...)
 (Cvt64Fto64 ...) => (I64TruncSatF64S ...)
-(Cvt32Fto32U ...) => (I64TruncSatF32U ...)
+
+(Cvt32Fto32U ...) => (I32TruncSatF32U ...)
 (Cvt32Fto64U ...) => (I64TruncSatF32U ...)
-(Cvt64Fto32U ...) => (I64TruncSatF64U ...)
+(Cvt64Fto32U ...) => (I32TruncSatF64U ...)
 (Cvt64Fto64U ...) => (I64TruncSatF64U ...)
 
 (Cvt32Fto64F ...) => (F64PromoteF32 ...)

src/cmd/compile/internal/ssa/_gen/WasmOps.go

@@ -222,10 +222,19 @@ func init() {
 		{name: "F64Mul", asm: "F64Mul", argLength: 2, reg: fp64_21, typ: "Float64"}, // arg0 * arg1
 		{name: "F64Div", asm: "F64Div", argLength: 2, reg: fp64_21, typ: "Float64"}, // arg0 / arg1
 
-		{name: "I64TruncSatF64S", asm: "I64TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to a signed integer (saturating)
+		{name: "I64TruncSatF64S", asm: "I64TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
-		{name: "I64TruncSatF64U", asm: "I64TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to an unsigned integer (saturating)
+		{name: "I64TruncSatF64U", asm: "I64TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
-		{name: "I64TruncSatF32S", asm: "I64TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to a signed integer (saturating)
+		{name: "I64TruncSatF32S", asm: "I64TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
-		{name: "I64TruncSatF32U", asm: "I64TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to an unsigned integer (saturating)
+		{name: "I64TruncSatF32U", asm: "I64TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
+
+		// It appears to be wasm convention that everything lands in a 64-bit register;
+		// the WASM instructions for these operations produce 32-bit width results, but
+		// wasm/ssa.go widens them appropriately to 64-bit results.
+		{name: "I32TruncSatF64S", asm: "I32TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
+		{name: "I32TruncSatF64U", asm: "I32TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
+		{name: "I32TruncSatF32S", asm: "I32TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
+		{name: "I32TruncSatF32U", asm: "I32TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
+
 		{name: "F32ConvertI64S", asm: "F32ConvertI64S", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp32}}, typ: "Float32"}, // converts the signed integer arg0 to a float
 		{name: "F32ConvertI64U", asm: "F32ConvertI64U", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp32}}, typ: "Float32"}, // converts the unsigned integer arg0 to a float
 		{name: "F64ConvertI64S", asm: "F64ConvertI64S", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp64}}, typ: "Float64"}, // converts the signed integer arg0 to a float

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

@@ -2980,6 +2980,10 @@ const (
 	OpWasmI64TruncSatF64U
 	OpWasmI64TruncSatF32S
 	OpWasmI64TruncSatF32U
+	OpWasmI32TruncSatF64S
+	OpWasmI32TruncSatF64U
+	OpWasmI32TruncSatF32S
+	OpWasmI32TruncSatF32U
 	OpWasmF32ConvertI64S
 	OpWasmF32ConvertI64U
 	OpWasmF64ConvertI64S
@@ -40296,6 +40300,58 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:   "I32TruncSatF64S",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF64S,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 281470681743360}, // F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
+	{
+		name:   "I32TruncSatF64U",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF64U,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 281470681743360}, // F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
+	{
+		name:   "I32TruncSatF32S",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF32S,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 4294901760}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
+	{
+		name:   "I32TruncSatF32U",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF32U,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 4294901760}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
 	{
 		name:   "F32ConvertI64S",
 		argLen: 1,

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

@@ -120,10 +120,10 @@ func rewriteValueWasm(v *Value) bool {
 		v.Op = OpWasmI64Ctz
 		return true
 	case OpCvt32Fto32:
-		v.Op = OpWasmI64TruncSatF32S
+		v.Op = OpWasmI32TruncSatF32S
 		return true
 	case OpCvt32Fto32U:
-		v.Op = OpWasmI64TruncSatF32U
+		v.Op = OpWasmI32TruncSatF32U
 		return true
 	case OpCvt32Fto64:
 		v.Op = OpWasmI64TruncSatF32S
@@ -143,13 +143,13 @@ func rewriteValueWasm(v *Value) bool {
 	case OpCvt32to64F:
 		return rewriteValueWasm_OpCvt32to64F(v)
 	case OpCvt64Fto32:
-		v.Op = OpWasmI64TruncSatF64S
+		v.Op = OpWasmI32TruncSatF64S
 		return true
 	case OpCvt64Fto32F:
 		v.Op = OpWasmF32DemoteF64
 		return true
 	case OpCvt64Fto32U:
-		v.Op = OpWasmI64TruncSatF64U
+		v.Op = OpWasmI32TruncSatF64U
 		return true
 	case OpCvt64Fto64:
 		v.Op = OpWasmI64TruncSatF64S

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

@@ -430,6 +430,17 @@ func ssaGenValueOnStack(s *ssagen.State, v *ssa.Value, extend bool) {
 		getValue64(s, v.Args[0])
 		s.Prog(v.Op.Asm())
 
+		// 32-bit integer conversion results
+	case ssa.OpWasmI32TruncSatF32S, ssa.OpWasmI32TruncSatF64S:
+		getValue64(s, v.Args[0])
+		s.Prog(v.Op.Asm())
+		s.Prog(wasm.AI64ExtendI32S)
+
+	case ssa.OpWasmI32TruncSatF32U, ssa.OpWasmI32TruncSatF64U:
+		getValue64(s, v.Args[0])
+		s.Prog(v.Op.Asm())
+		s.Prog(wasm.AI64ExtendI32U)
+
 	case ssa.OpWasmF32DemoteF64:
 		getValue64(s, v.Args[0])
 		s.Prog(v.Op.Asm())

test/convert5.go

@@ -4,11 +4,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !wasm
-
-// TODO fix this to work for wasm
-// Doing more than this, however, expands the change.
-
 package main
 
 import (