cmd/compile: fold IsInBounds of modulo.
In b we only need the division by 0 check.
func b(i uint, v []byte) byte {
return v[i%uint(len(v))]
}
Updates #15079.
Change-Id: Ic7491e677dd57cd6ba577efbce576dbb6e023cbd
Reviewed-on: https://go-review.googlesource.com/21502
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Ahmed Waheed <oneofone@gmail.com>
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index e83e8e7..14b1769 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -2815,6 +2815,38 @@
v.AuxInt = b2i(0 <= c && c < d)
return true
}
+ // match: (IsInBounds (Mod32u _ y) y)
+ // cond:
+ // result: (ConstBool [1])
+ for {
+ v_0 := v.Args[0]
+ if v_0.Op != OpMod32u {
+ break
+ }
+ y := v_0.Args[1]
+ if y != v.Args[1] {
+ break
+ }
+ v.reset(OpConstBool)
+ v.AuxInt = 1
+ return true
+ }
+ // match: (IsInBounds (Mod64u _ y) y)
+ // cond:
+ // result: (ConstBool [1])
+ for {
+ v_0 := v.Args[0]
+ if v_0.Op != OpMod64u {
+ break
+ }
+ y := v_0.Args[1]
+ if y != v.Args[1] {
+ break
+ }
+ v.reset(OpConstBool)
+ v.AuxInt = 1
+ return true
+ }
return false
}
func rewriteValuegeneric_OpIsSliceInBounds(v *Value, config *Config) bool {
