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

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 95844381c28aa498e4a35e800f0ce4eabfdfb39e..44583e8e340926b9fd2c4fac87046e0368751c98 100644 (file)
--- 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 ef9b83192ccbe443f46a59b8a0a4ee8bdfc82ca1..60ba120e48dad67a0ddaf07432e033c4475c8da9 100644 (file)
--- 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
 }