cmd/compile: fix cmpstring rewrite rule
We need to ensure that the Select0 lives in the same block as
its argument. Divide up the rule into 2 so that we can put the
parts in the right places.
(This would be simpler if we could use @block syntax mid-rule, but
that feature currently only works at the top level.)
This fixes the ssacheck builder after CL 578835
Change-Id: Id26a01d9fac0684e0b732d35d0f7999f6de07825
Reviewed-on: https://go-review.googlesource.com/c/go/+/580815
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index 398601e..70bac21 100644
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -2799,7 +2799,11 @@
// same memory state can reuse the results of the first call.
// See issue 61725.
// Note that this could pretty easily generalize to any pure function.
-(StaticLECall {f} x y m:(SelectN [1] c:(StaticLECall {g} x y mem)))
+(SelectN [0] (StaticLECall {f} x y (SelectN [1] c:(StaticLECall {g} x y mem))))
&& isSameCall(f, "runtime.cmpstring")
&& isSameCall(g, "runtime.cmpstring")
-=> (MakeResult (SelectN [0] <typ.Int> c) m)
+=> @c.Block (SelectN [0] <typ.Int> c)
+
+// If we don't use the result of cmpstring, might as well not call it.
+// Note that this could pretty easily generalize to any pure function.
+(SelectN [1] c:(StaticLECall {f} _ _ mem)) && c.Uses == 1 && isSameCall(f, "runtime.cmpstring") && clobber(c) => mem
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 98c94bc..cfed828 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -28081,6 +28081,7 @@
v_0 := v.Args[0]
b := v.Block
config := b.Func.Config
+ typ := &b.Func.Config.Types
// match: (SelectN [0] (MakeResult x ___))
// result: x
for {
@@ -28439,6 +28440,55 @@
v.copyOf(newLen)
return true
}
+ // match: (SelectN [0] (StaticLECall {f} x y (SelectN [1] c:(StaticLECall {g} x y mem))))
+ // cond: isSameCall(f, "runtime.cmpstring") && isSameCall(g, "runtime.cmpstring")
+ // result: @c.Block (SelectN [0] <typ.Int> c)
+ for {
+ if auxIntToInt64(v.AuxInt) != 0 || v_0.Op != OpStaticLECall || len(v_0.Args) != 3 {
+ break
+ }
+ f := auxToCall(v_0.Aux)
+ _ = v_0.Args[2]
+ x := v_0.Args[0]
+ y := v_0.Args[1]
+ v_0_2 := v_0.Args[2]
+ if v_0_2.Op != OpSelectN || auxIntToInt64(v_0_2.AuxInt) != 1 {
+ break
+ }
+ c := v_0_2.Args[0]
+ if c.Op != OpStaticLECall || len(c.Args) != 3 {
+ break
+ }
+ g := auxToCall(c.Aux)
+ if x != c.Args[0] || y != c.Args[1] || !(isSameCall(f, "runtime.cmpstring") && isSameCall(g, "runtime.cmpstring")) {
+ break
+ }
+ b = c.Block
+ v0 := b.NewValue0(v.Pos, OpSelectN, typ.Int)
+ v.copyOf(v0)
+ v0.AuxInt = int64ToAuxInt(0)
+ v0.AddArg(c)
+ return true
+ }
+ // match: (SelectN [1] c:(StaticLECall {f} _ _ mem))
+ // cond: c.Uses == 1 && isSameCall(f, "runtime.cmpstring") && clobber(c)
+ // result: mem
+ for {
+ if auxIntToInt64(v.AuxInt) != 1 {
+ break
+ }
+ c := v_0
+ if c.Op != OpStaticLECall || len(c.Args) != 3 {
+ break
+ }
+ f := auxToCall(c.Aux)
+ mem := c.Args[2]
+ if !(c.Uses == 1 && isSameCall(f, "runtime.cmpstring") && clobber(c)) {
+ break
+ }
+ v.copyOf(mem)
+ return true
+ }
return false
}
func rewriteValuegeneric_OpSignExt16to32(v *Value) bool {
@@ -29311,36 +29361,6 @@
v.AddArg2(v0, mem)
return true
}
- // match: (StaticLECall {f} x y m:(SelectN [1] c:(StaticLECall {g} x y mem)))
- // cond: isSameCall(f, "runtime.cmpstring") && isSameCall(g, "runtime.cmpstring")
- // result: (MakeResult (SelectN [0] <typ.Int> c) m)
- for {
- if len(v.Args) != 3 {
- break
- }
- f := auxToCall(v.Aux)
- _ = v.Args[2]
- x := v.Args[0]
- y := v.Args[1]
- m := v.Args[2]
- if m.Op != OpSelectN || auxIntToInt64(m.AuxInt) != 1 {
- break
- }
- c := m.Args[0]
- if c.Op != OpStaticLECall || len(c.Args) != 3 {
- break
- }
- g := auxToCall(c.Aux)
- if x != c.Args[0] || y != c.Args[1] || !(isSameCall(f, "runtime.cmpstring") && isSameCall(g, "runtime.cmpstring")) {
- break
- }
- v.reset(OpMakeResult)
- v0 := b.NewValue0(v.Pos, OpSelectN, typ.Int)
- v0.AuxInt = int64ToAuxInt(0)
- v0.AddArg(c)
- v.AddArg2(v0, m)
- return true
- }
return false
}
func rewriteValuegeneric_OpStore(v *Value) bool {
