cmd/compile: convert some condmoves in XOR

Similar to CL 685676 but for XOR.

Change-Id: Ib5ffd4c13348f176a808b3218fdbbafc2c42794f
Reviewed-on: https://go-review.googlesource.com/c/go/+/760921
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Junyang Shao <shaojunyang@google.com>
Auto-Submit: Jorropo <jorropo.pgm@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

2 files changed, 106 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index fe34b53be2..7dcf818976 100644
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -2316,6 +2316,10 @@
 (CondSelect (Or8 <t> x (Const8 [1])) x bool) => (Or8 x (CvtBoolToUint8 <t> bool))
 (CondSelect (Or(64|32|16) <t> x (Const(64|32|16) [1])) x bool) => (Or(64|32|16) x (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool)))
 
+// if b { x ^= 1 } => x ^= b
+(CondSelect (Xor8 <t> x (Const8 [1])) x bool) => (Xor8 x (CvtBoolToUint8 <t> bool))
+(CondSelect (Xor(64|32|16) <t> x (Const(64|32|16) [1])) x bool) => (Xor(64|32|16) x (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool)))
+
 // bool(int(x)) => x
 (Neq8                                (CvtBoolToUint8 x)  (Const8          [0])) => x
 (Neq8                                (CvtBoolToUint8 x)  (Const8          [1])) => (Not x)
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 1a80f3961b..263302c7e7 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -6474,6 +6474,108 @@ func rewriteValuegeneric_OpCondSelect(v *Value) bool {
 		}
 		break
 	}
+	// match: (CondSelect (Xor8 <t> x (Const8 [1])) x bool)
+	// result: (Xor8 x (CvtBoolToUint8 <t> bool))
+	for {
+		if v_0.Op != OpXor8 {
+			break
+		}
+		t := v_0.Type
+		_ = v_0.Args[1]
+		v_0_0 := v_0.Args[0]
+		v_0_1 := v_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
+			x := v_0_0
+			if v_0_1.Op != OpConst8 || auxIntToInt8(v_0_1.AuxInt) != 1 || x != v_1 {
+				continue
+			}
+			bool := v_2
+			v.reset(OpXor8)
+			v0 := b.NewValue0(v.Pos, OpCvtBoolToUint8, t)
+			v0.AddArg(bool)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
+	// match: (CondSelect (Xor64 <t> x (Const64 [1])) x bool)
+	// result: (Xor64 x (ZeroExt8to64 <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool)))
+	for {
+		if v_0.Op != OpXor64 {
+			break
+		}
+		t := v_0.Type
+		_ = v_0.Args[1]
+		v_0_0 := v_0.Args[0]
+		v_0_1 := v_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
+			x := v_0_0
+			if v_0_1.Op != OpConst64 || auxIntToInt64(v_0_1.AuxInt) != 1 || x != v_1 {
+				continue
+			}
+			bool := v_2
+			v.reset(OpXor64)
+			v0 := b.NewValue0(v.Pos, OpZeroExt8to64, t)
+			v1 := b.NewValue0(v.Pos, OpCvtBoolToUint8, types.Types[types.TUINT8])
+			v1.AddArg(bool)
+			v0.AddArg(v1)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
+	// match: (CondSelect (Xor32 <t> x (Const32 [1])) x bool)
+	// result: (Xor32 x (ZeroExt8to32 <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool)))
+	for {
+		if v_0.Op != OpXor32 {
+			break
+		}
+		t := v_0.Type
+		_ = v_0.Args[1]
+		v_0_0 := v_0.Args[0]
+		v_0_1 := v_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
+			x := v_0_0
+			if v_0_1.Op != OpConst32 || auxIntToInt32(v_0_1.AuxInt) != 1 || x != v_1 {
+				continue
+			}
+			bool := v_2
+			v.reset(OpXor32)
+			v0 := b.NewValue0(v.Pos, OpZeroExt8to32, t)
+			v1 := b.NewValue0(v.Pos, OpCvtBoolToUint8, types.Types[types.TUINT8])
+			v1.AddArg(bool)
+			v0.AddArg(v1)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
+	// match: (CondSelect (Xor16 <t> x (Const16 [1])) x bool)
+	// result: (Xor16 x (ZeroExt8to16 <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool)))
+	for {
+		if v_0.Op != OpXor16 {
+			break
+		}
+		t := v_0.Type
+		_ = v_0.Args[1]
+		v_0_0 := v_0.Args[0]
+		v_0_1 := v_0.Args[1]
+		for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
+			x := v_0_0
+			if v_0_1.Op != OpConst16 || auxIntToInt16(v_0_1.AuxInt) != 1 || x != v_1 {
+				continue
+			}
+			bool := v_2
+			v.reset(OpXor16)
+			v0 := b.NewValue0(v.Pos, OpZeroExt8to16, t)
+			v1 := b.NewValue0(v.Pos, OpCvtBoolToUint8, types.Types[types.TUINT8])
+			v1.AddArg(bool)
+			v0.AddArg(v1)
+			v.AddArg2(x, v0)
+			return true
+		}
+		break
+	}
 	return false
 }
 func rewriteValuegeneric_OpConstInterface(v *Value) bool {