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authorXiaolin Zhao <zhaoxiaolin@loongson.cn>2025-12-01 14:46:23 +0800
committerGopher Robot <gobot@golang.org>2026-01-23 08:38:00 -0800
commit021d5ca042775537d707c6f5ae2f53f57dac243f (patch)
tree9c060d1f89816259207c1f5992f16e00a02d1bb2 /src/cmd
parentc04335e33a6915ae4edc9c9f94a909a46557f99a (diff)
downloadgo-021d5ca042775537d707c6f5ae2f53f57dac243f.tar.xz
cmd/compile: avoid extending when already sufficiently shifted on loong64
This reduces 744 instructions from the go toolchain binary on loong64. file before after Δ % asm 599282 599222 -60 -0.0100% cgo 513606 513534 -72 -0.0140% compile 2939250 2939146 -104 -0.0035% cover 564136 564056 -80 -0.0142% fix 895622 895546 -76 -0.0085% link 759460 759376 -84 -0.0111% preprofile 264960 264916 -44 -0.0166% vet 869964 869888 -76 -0.0087% go 1712990 1712890 -100 -0.0058% gofmt 346416 346368 -48 -0.0139% total 9465686 9464942 -744 -0.0079% Change-Id: I32dfa7506d0458ca0b6de83b030c330cd2b82176 Reviewed-on: https://go-review.googlesource.com/c/go/+/725720 Auto-Submit: Keith Randall <khr@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Carlos Amedee <carlos@golang.org> Reviewed-by: Keith Randall <khr@google.com>
Diffstat (limited to 'src/cmd')
-rw-r--r--src/cmd/compile/internal/ssa/_gen/LOONG64.rules5
-rw-r--r--src/cmd/compile/internal/ssa/rewriteLOONG64.go40
2 files changed, 45 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/_gen/LOONG64.rules b/src/cmd/compile/internal/ssa/_gen/LOONG64.rules
index b15043032c..a40603e93d 100644
--- a/src/cmd/compile/internal/ssa/_gen/LOONG64.rules
+++ b/src/cmd/compile/internal/ssa/_gen/LOONG64.rules
@@ -843,6 +843,11 @@
(MOVBUreg (ANDconst [c] x)) => (ANDconst [c&0xff] x)
+// Avoid extending when already sufficiently shifted.
+(MOVBUreg x:(SRLconst [c] y)) && c >= 24 => x
+(MOVHUreg x:(SRLconst [c] y)) && c >= 16 => x
+(MOVWUreg x:(SRLconst [c] y)) => x
+
// Avoid extending when already sufficiently masked.
(MOVBreg x:(ANDconst [c] y)) && c >= 0 && int64(int8(c)) == c => x
(MOVHreg x:(ANDconst [c] y)) && c >= 0 && int64(int16(c)) == c => x
diff --git a/src/cmd/compile/internal/ssa/rewriteLOONG64.go b/src/cmd/compile/internal/ssa/rewriteLOONG64.go
index 30ce419d40..37aedcbe6e 100644
--- a/src/cmd/compile/internal/ssa/rewriteLOONG64.go
+++ b/src/cmd/compile/internal/ssa/rewriteLOONG64.go
@@ -2677,6 +2677,21 @@ func rewriteValueLOONG64_OpLOONG64MOVBUreg(v *Value) bool {
v.AddArg(x)
return true
}
+ // match: (MOVBUreg x:(SRLconst [c] y))
+ // cond: c >= 24
+ // result: x
+ for {
+ x := v_0
+ if x.Op != OpLOONG64SRLconst {
+ break
+ }
+ c := auxIntToInt64(x.AuxInt)
+ if !(c >= 24) {
+ break
+ }
+ v.copyOf(x)
+ return true
+ }
// match: (MOVBUreg x:(ANDconst [c] y))
// cond: c >= 0 && int64(uint8(c)) == c
// result: x
@@ -4067,6 +4082,21 @@ func rewriteValueLOONG64_OpLOONG64MOVHUreg(v *Value) bool {
v.AuxInt = int64ToAuxInt(int64(uint16(c)))
return true
}
+ // match: (MOVHUreg x:(SRLconst [c] y))
+ // cond: c >= 16
+ // result: x
+ for {
+ x := v_0
+ if x.Op != OpLOONG64SRLconst {
+ break
+ }
+ c := auxIntToInt64(x.AuxInt)
+ if !(c >= 16) {
+ break
+ }
+ v.copyOf(x)
+ return true
+ }
// match: (MOVHUreg x:(ANDconst [c] y))
// cond: c >= 0 && int64(uint16(c)) == c
// result: x
@@ -5301,6 +5331,16 @@ func rewriteValueLOONG64_OpLOONG64MOVWUreg(v *Value) bool {
v.AuxInt = int64ToAuxInt(int64(uint32(c)))
return true
}
+ // match: (MOVWUreg x:(SRLconst [c] y))
+ // result: x
+ for {
+ x := v_0
+ if x.Op != OpLOONG64SRLconst {
+ break
+ }
+ v.copyOf(x)
+ return true
+ }
// match: (MOVWUreg x:(ANDconst [c] y))
// cond: c >= 0 && int64(uint32(c)) == c
// result: x