From 4e3ac1190c1a4e9084879da585420d97e372818c Mon Sep 17 00:00:00 2001
From: Jorropo <jorropo.pgm@gmail.com>
Date: Mon, 18 Apr 2022 07:29:32 +0200
Subject: [PATCH] cmd/compile: optimise x | ^x

---
 .../compile/internal/ssa/gen/generic.rules    |  3 +-
 .../compile/internal/ssa/rewritegeneric.go    | 68 +++++++++++++++++++
 2 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/src/cmd/compile/internal/ssa/gen/generic.rules b/src/cmd/compile/internal/ssa/gen/generic.rules
index cae5633d48..703be65379 100644
--- a/src/cmd/compile/internal/ssa/gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/gen/generic.rules
@@ -515,8 +515,9 @@
 
 // simplifications
 (Or(64|32|16|8) x x) => x
-(Or(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
+(Or(64|32|16|8) (Const(64|32|16|8)  [0]) x) => x
 (Or(64|32|16|8) (Const(64|32|16|8) [-1]) _) => (Const(64|32|16|8) [-1])
+(Or(64|32|16|8) (Com(64|32|16|8)     x)  x) => (Const(64|32|16|8) [-1])
 
 (And(64|32|16|8) x x) => x
 (And(64|32|16|8) (Const(64|32|16|8) [-1]) x) => x
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 5b0af128c3..e9c5fb8d1a 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -17160,6 +17160,23 @@ func rewriteValuegeneric_OpOr16(v *Value) bool {
 		}
 		break
 	}
+	// match: (Or16 (Com16 x) x)
+	// result: (Const16 [-1])
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpCom16 {
+				continue
+			}
+			x := v_0.Args[0]
+			if x != v_1 {
+				continue
+			}
+			v.reset(OpConst16)
+			v.AuxInt = int16ToAuxInt(-1)
+			return true
+		}
+		break
+	}
 	// match: (Or16 x (Or16 x y))
 	// result: (Or16 x y)
 	for {
@@ -17338,6 +17355,23 @@ func rewriteValuegeneric_OpOr32(v *Value) bool {
 		}
 		break
 	}
+	// match: (Or32 (Com32 x) x)
+	// result: (Const32 [-1])
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpCom32 {
+				continue
+			}
+			x := v_0.Args[0]
+			if x != v_1 {
+				continue
+			}
+			v.reset(OpConst32)
+			v.AuxInt = int32ToAuxInt(-1)
+			return true
+		}
+		break
+	}
 	// match: (Or32 x (Or32 x y))
 	// result: (Or32 x y)
 	for {
@@ -17516,6 +17550,23 @@ func rewriteValuegeneric_OpOr64(v *Value) bool {
 		}
 		break
 	}
+	// match: (Or64 (Com64 x) x)
+	// result: (Const64 [-1])
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpCom64 {
+				continue
+			}
+			x := v_0.Args[0]
+			if x != v_1 {
+				continue
+			}
+			v.reset(OpConst64)
+			v.AuxInt = int64ToAuxInt(-1)
+			return true
+		}
+		break
+	}
 	// match: (Or64 x (Or64 x y))
 	// result: (Or64 x y)
 	for {
@@ -17694,6 +17745,23 @@ func rewriteValuegeneric_OpOr8(v *Value) bool {
 		}
 		break
 	}
+	// match: (Or8 (Com8 x) x)
+	// result: (Const8 [-1])
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpCom8 {
+				continue
+			}
+			x := v_0.Args[0]
+			if x != v_1 {
+				continue
+			}
+			v.reset(OpConst8)
+			v.AuxInt = int8ToAuxInt(-1)
+			return true
+		}
+		break
+	}
 	// match: (Or8 x (Or8 x y))
 	// result: (Or8 x y)
 	for {