From: limeidan <limeidan@loongson.cn>
Date: Mon, 28 Jul 2025 06:46:45 +0000 (+0800)
Subject: cmd/compile/internal/ssa: use BEQ/BNE to optimize the combination of XOR and EQ/NE... 
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=b266318cf714ab34be01e32d7338053ca6dcb294;p=gostls13.git

cmd/compile/internal/ssa: use BEQ/BNE to optimize the combination of XOR and EQ/NE on loong64

Reduce the number of go toolchain instructions on loong64 as follows:

	file	    before	after	     Δ		 %
	go	    1599056	1590560	    -8496    -0.5313%
	gofmt	    326188	326104	    -84	     -0.0258%
	asm	    563482	561250	    -2232    -0.3961%
	cgo	    488644	485252	    -3392    -0.6942%
	compile	    2504614	2486388	    -18226   -0.7277%
	cover	    526322	523270	    -3052    -0.5799%
	link	    714532	711124	    -3408    -0.4770%
	preprofile  242316	241112	    -1204    -0.4969%
	vet	    794446	786118	    -8328    -1.0483%

Change-Id: I0914889119a28ea672b694529ef54513fbb3f3b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/693875
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Keith Randall <khr@google.com>
---

diff --git a/src/cmd/compile/internal/ssa/_gen/LOONG64latelower.rules b/src/cmd/compile/internal/ssa/_gen/LOONG64latelower.rules
index 95844381c2..44583e8e34 100644
--- a/src/cmd/compile/internal/ssa/_gen/LOONG64latelower.rules
+++ b/src/cmd/compile/internal/ssa/_gen/LOONG64latelower.rules
@@ -4,3 +4,6 @@
 
 // Prefer addition when shifting left by one.
 (SLLVconst [1] x) => (ADDV x x)
+
+(EQZ (XOR x y) yes no) => (BEQ x y yes no)
+(NEZ (XOR x y) yes no) => (BNE x y yes no)
diff --git a/src/cmd/compile/internal/ssa/rewriteLOONG64latelower.go b/src/cmd/compile/internal/ssa/rewriteLOONG64latelower.go
index ef9b83192c..60ba120e48 100644
--- a/src/cmd/compile/internal/ssa/rewriteLOONG64latelower.go
+++ b/src/cmd/compile/internal/ssa/rewriteLOONG64latelower.go
@@ -25,5 +25,37 @@ func rewriteValueLOONG64latelower_OpLOONG64SLLVconst(v *Value) bool {
 	return false
 }
 func rewriteBlockLOONG64latelower(b *Block) bool {
+	switch b.Kind {
+	case BlockLOONG64EQZ:
+		// match: (EQZ (XOR x y) yes no)
+		// result: (BEQ x y yes no)
+		for b.Controls[0].Op == OpLOONG64XOR {
+			v_0 := b.Controls[0]
+			_ = 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
+				y := v_0_1
+				b.resetWithControl2(BlockLOONG64BEQ, x, y)
+				return true
+			}
+		}
+	case BlockLOONG64NEZ:
+		// match: (NEZ (XOR x y) yes no)
+		// result: (BNE x y yes no)
+		for b.Controls[0].Op == OpLOONG64XOR {
+			v_0 := b.Controls[0]
+			_ = 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
+				y := v_0_1
+				b.resetWithControl2(BlockLOONG64BNE, x, y)
+				return true
+			}
+		}
+	}
 	return false
 }