cmd/compile/internal/ssa: mark boolean instructions commutative

Mark AndB, OrB, EqB, and NeqB as commutative.

Change-Id: Ife7cfcb9780cc5dd669617cb52339ab336667da4
Reviewed-on: https://go-review.googlesource.com/42515
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

3 files changed, 123 insertions, 17 deletions

diff --git a/src/cmd/compile/internal/ssa/gen/genericOps.go b/src/cmd/compile/internal/ssa/gen/genericOps.go
index e9a90963ab..d962e4a193 100644
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@@ -218,11 +218,11 @@ var genericOps = []opData{
 	{name: "Geq64F", argLength: 2, typ: "Bool"},
 
 	// boolean ops
-	{name: "AndB", argLength: 2, typ: "Bool"}, // arg0 && arg1 (not shortcircuited)
-	{name: "OrB", argLength: 2, typ: "Bool"},  // arg0 || arg1 (not shortcircuited)
-	{name: "EqB", argLength: 2, typ: "Bool"},  // arg0 == arg1
-	{name: "NeqB", argLength: 2, typ: "Bool"}, // arg0 != arg1
-	{name: "Not", argLength: 1, typ: "Bool"},  // !arg0, boolean
+	{name: "AndB", argLength: 2, commutative: true, typ: "Bool"}, // arg0 && arg1 (not shortcircuited)
+	{name: "OrB", argLength: 2, commutative: true, typ: "Bool"},  // arg0 || arg1 (not shortcircuited)
+	{name: "EqB", argLength: 2, commutative: true, typ: "Bool"},  // arg0 == arg1
+	{name: "NeqB", argLength: 2, commutative: true, typ: "Bool"}, // arg0 != arg1
+	{name: "Not", argLength: 1, typ: "Bool"},                     // !arg0, boolean
 
 	// 1-input ops
 	{name: "Neg8", argLength: 1}, // -arg0
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 32d928388f..938743897e 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -21751,24 +21751,28 @@ var opcodeTable = [...]opInfo{
 		generic: true,
 	},
 	{
-		name:    "AndB",
-		argLen:  2,
-		generic: true,
+		name:        "AndB",
+		argLen:      2,
+		commutative: true,
+		generic:     true,
 	},
 	{
-		name:    "OrB",
-		argLen:  2,
-		generic: true,
+		name:        "OrB",
+		argLen:      2,
+		commutative: true,
+		generic:     true,
 	},
 	{
-		name:    "EqB",
-		argLen:  2,
-		generic: true,
+		name:        "EqB",
+		argLen:      2,
+		commutative: true,
+		generic:     true,
 	},
 	{
-		name:    "NeqB",
-		argLen:  2,
-		generic: true,
+		name:        "NeqB",
+		argLen:      2,
+		commutative: true,
+		generic:     true,
 	},
 	{
 		name:    "Not",
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 72d9c818b2..88cc39a65d 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -7894,6 +7894,24 @@ func rewriteValuegeneric_OpEqB_0(v *Value) bool {
 		v.AuxInt = b2i(c == d)
 		return true
 	}
+	// match: (EqB (ConstBool [d]) (ConstBool [c]))
+	// cond:
+	// result: (ConstBool [b2i(c == d)])
+	for {
+		v_0 := v.Args[0]
+		if v_0.Op != OpConstBool {
+			break
+		}
+		d := v_0.AuxInt
+		v_1 := v.Args[1]
+		if v_1.Op != OpConstBool {
+			break
+		}
+		c := v_1.AuxInt
+		v.reset(OpConstBool)
+		v.AuxInt = b2i(c == d)
+		return true
+	}
 	// match: (EqB (ConstBool [0]) x)
 	// cond:
 	// result: (Not x)
@@ -7910,6 +7928,22 @@ func rewriteValuegeneric_OpEqB_0(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
+	// match: (EqB x (ConstBool [0]))
+	// cond:
+	// result: (Not x)
+	for {
+		x := v.Args[0]
+		v_1 := v.Args[1]
+		if v_1.Op != OpConstBool {
+			break
+		}
+		if v_1.AuxInt != 0 {
+			break
+		}
+		v.reset(OpNot)
+		v.AddArg(x)
+		return true
+	}
 	// match: (EqB (ConstBool [1]) x)
 	// cond:
 	// result: x
@@ -7927,6 +7961,23 @@ func rewriteValuegeneric_OpEqB_0(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
+	// match: (EqB x (ConstBool [1]))
+	// cond:
+	// result: x
+	for {
+		x := v.Args[0]
+		v_1 := v.Args[1]
+		if v_1.Op != OpConstBool {
+			break
+		}
+		if v_1.AuxInt != 1 {
+			break
+		}
+		v.reset(OpCopy)
+		v.Type = x.Type
+		v.AddArg(x)
+		return true
+	}
 	return false
 }
 func rewriteValuegeneric_OpEqInter_0(v *Value) bool {
@@ -14438,6 +14489,24 @@ func rewriteValuegeneric_OpNeqB_0(v *Value) bool {
 		v.AuxInt = b2i(c != d)
 		return true
 	}
+	// match: (NeqB (ConstBool [d]) (ConstBool [c]))
+	// cond:
+	// result: (ConstBool [b2i(c != d)])
+	for {
+		v_0 := v.Args[0]
+		if v_0.Op != OpConstBool {
+			break
+		}
+		d := v_0.AuxInt
+		v_1 := v.Args[1]
+		if v_1.Op != OpConstBool {
+			break
+		}
+		c := v_1.AuxInt
+		v.reset(OpConstBool)
+		v.AuxInt = b2i(c != d)
+		return true
+	}
 	// match: (NeqB (ConstBool [0]) x)
 	// cond:
 	// result: x
@@ -14455,6 +14524,23 @@ func rewriteValuegeneric_OpNeqB_0(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
+	// match: (NeqB x (ConstBool [0]))
+	// cond:
+	// result: x
+	for {
+		x := v.Args[0]
+		v_1 := v.Args[1]
+		if v_1.Op != OpConstBool {
+			break
+		}
+		if v_1.AuxInt != 0 {
+			break
+		}
+		v.reset(OpCopy)
+		v.Type = x.Type
+		v.AddArg(x)
+		return true
+	}
 	// match: (NeqB (ConstBool [1]) x)
 	// cond:
 	// result: (Not x)
@@ -14471,6 +14557,22 @@ func rewriteValuegeneric_OpNeqB_0(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
+	// match: (NeqB x (ConstBool [1]))
+	// cond:
+	// result: (Not x)
+	for {
+		x := v.Args[0]
+		v_1 := v.Args[1]
+		if v_1.Op != OpConstBool {
+			break
+		}
+		if v_1.AuxInt != 1 {
+			break
+		}
+		v.reset(OpNot)
+		v.AddArg(x)
+		return true
+	}
 	return false
 }
 func rewriteValuegeneric_OpNeqInter_0(v *Value) bool {