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mirror of https://github.com/golang/go synced 2024-11-11 19:21:37 -07:00

cmd/compile: fix wrong optimization for eliding Not in Phi

The previous rule may move the phi value into a wrong block.
This CL make it only rewrite the phi value not the If block,
so that the phi value will stay in old block.

Fixes #56777

Change-Id: I9479a5c7f28529786968413d35b82a16181bb1f1
Reviewed-on: https://go-review.googlesource.com/c/go/+/451496
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Wayne Zuo 2022-11-17 18:10:00 +08:00 committed by David Chase
parent 205f636e0a
commit 8893da7c72
3 changed files with 87 additions and 30 deletions

View File

@ -961,10 +961,11 @@
(NilCheck (GetG mem) mem) => mem
(If (Not cond) yes no) => (If cond no yes)
(If (Phi <t> nx:(Not x) ny:(Not y)) yes no) && nx.Uses == 1 && ny.Uses == 1 => (If (Phi <t> x y) no yes)
(If (ConstBool [c]) yes no) && c => (First yes no)
(If (ConstBool [c]) yes no) && !c => (First no yes)
(Phi <t> nx:(Not x) ny:(Not y)) && nx.Uses == 1 && ny.Uses == 1 => (Not (Phi <t> x y))
// Get rid of Convert ops for pointer arithmetic on unsafe.Pointer.
(Convert (Add(64|32) (Convert ptr mem) off) mem) => (AddPtr ptr off)
(Convert (Convert ptr mem) mem) => ptr

View File

@ -21903,6 +21903,7 @@ func rewriteValuegeneric_OpOrB(v *Value) bool {
return false
}
func rewriteValuegeneric_OpPhi(v *Value) bool {
b := v.Block
// match: (Phi (Const8 [c]) (Const8 [c]))
// result: (Const8 [c])
for {
@ -21983,6 +21984,34 @@ func rewriteValuegeneric_OpPhi(v *Value) bool {
v.AuxInt = int64ToAuxInt(c)
return true
}
// match: (Phi <t> nx:(Not x) ny:(Not y))
// cond: nx.Uses == 1 && ny.Uses == 1
// result: (Not (Phi <t> x y))
for {
if len(v.Args) != 2 {
break
}
t := v.Type
_ = v.Args[1]
nx := v.Args[0]
if nx.Op != OpNot {
break
}
x := nx.Args[0]
ny := v.Args[1]
if ny.Op != OpNot {
break
}
y := ny.Args[0]
if !(nx.Uses == 1 && ny.Uses == 1) {
break
}
v.reset(OpNot)
v0 := b.NewValue0(v.Pos, OpPhi, t)
v0.AddArg2(x, y)
v.AddArg(v0)
return true
}
return false
}
func rewriteValuegeneric_OpPtrIndex(v *Value) bool {
@ -32462,35 +32491,6 @@ func rewriteBlockgeneric(b *Block) bool {
b.swapSuccessors()
return true
}
// match: (If (Phi <t> nx:(Not x) ny:(Not y)) yes no)
// cond: nx.Uses == 1 && ny.Uses == 1
// result: (If (Phi <t> x y) no yes)
for b.Controls[0].Op == OpPhi {
v_0 := b.Controls[0]
if len(v_0.Args) != 2 {
break
}
t := v_0.Type
_ = v_0.Args[1]
nx := v_0.Args[0]
if nx.Op != OpNot {
break
}
x := nx.Args[0]
ny := v_0.Args[1]
if ny.Op != OpNot {
break
}
y := ny.Args[0]
if !(nx.Uses == 1 && ny.Uses == 1) {
break
}
v0 := b.NewValue0(v_0.Pos, OpPhi, t)
v0.AddArg2(x, y)
b.resetWithControl(BlockIf, v0)
b.swapSuccessors()
return true
}
// match: (If (ConstBool [c]) yes no)
// cond: c
// result: (First yes no)

View File

@ -0,0 +1,56 @@
// compile
// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package p
func fn(setText []rune, negate bool) int {
ranges := []singleRange{}
if len(setText) > 0 {
fillFirst := false
l := len(setText)
if negate {
if setText[0] == 0 {
setText = setText[1:]
} else {
l++
fillFirst = true
}
}
if l%2 == 0 {
ranges = make([]singleRange, l/2)
} else {
ranges = make([]singleRange, l/2+1)
}
first := true
if fillFirst {
ranges[0] = singleRange{first: 0}
first = false
}
i := 0
for _, r := range setText {
if first {
// lower bound in a new range
ranges[i] = singleRange{first: r}
first = false
} else {
ranges[i].last = r - 1
i++
first = true
}
}
}
return len(ranges)
}
type singleRange struct {
first rune
last rune
}