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cmd/compile: add additional flag constant folding rules

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Fixes #73200

Change-Id: I77518d37acd838acf79ed113194bac5e2c30897f
Reviewed-on: https://go-review.googlesource.com/c/go/+/663535
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Keith Randall 2025-04-07 10:33:31 -07:00
parent 92309ff771
commit af278bfb1f
3 changed files with 70 additions and 10 deletions
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22
src/cmd/compile/internal/ssa/_gen/ARM64.rules
View File

@ -1385,16 +1385,18 @@
(CSNEG [cc] x y (InvertFlags cmp)) => (CSNEG [arm64Invert(cc)] x y cmp)
// absorb flag constants into boolean values
(Equal (FlagConstant [fc])) => (MOVDconst [b2i(fc.eq())])
(NotEqual (FlagConstant [fc])) => (MOVDconst [b2i(fc.ne())])
(LessThan (FlagConstant [fc])) => (MOVDconst [b2i(fc.lt())])
(LessThanU (FlagConstant [fc])) => (MOVDconst [b2i(fc.ult())])
(LessEqual (FlagConstant [fc])) => (MOVDconst [b2i(fc.le())])
(LessEqualU (FlagConstant [fc])) => (MOVDconst [b2i(fc.ule())])
(GreaterThan (FlagConstant [fc])) => (MOVDconst [b2i(fc.gt())])
(GreaterThanU (FlagConstant [fc])) => (MOVDconst [b2i(fc.ugt())])
(GreaterEqual (FlagConstant [fc])) => (MOVDconst [b2i(fc.ge())])
(GreaterEqualU (FlagConstant [fc])) => (MOVDconst [b2i(fc.uge())])
(Equal (FlagConstant [fc])) => (MOVDconst [b2i(fc.eq())])
(NotEqual (FlagConstant [fc])) => (MOVDconst [b2i(fc.ne())])
(LessThan (FlagConstant [fc])) => (MOVDconst [b2i(fc.lt())])
(LessThanU (FlagConstant [fc])) => (MOVDconst [b2i(fc.ult())])
(LessEqual (FlagConstant [fc])) => (MOVDconst [b2i(fc.le())])
(LessEqualU (FlagConstant [fc])) => (MOVDconst [b2i(fc.ule())])
(GreaterThan (FlagConstant [fc])) => (MOVDconst [b2i(fc.gt())])
(GreaterThanU (FlagConstant [fc])) => (MOVDconst [b2i(fc.ugt())])
(GreaterEqual (FlagConstant [fc])) => (MOVDconst [b2i(fc.ge())])
(GreaterEqualU (FlagConstant [fc])) => (MOVDconst [b2i(fc.uge())])
(LessThanNoov (FlagConstant [fc])) => (MOVDconst [b2i(fc.ltNoov())])
(GreaterEqualNoov (FlagConstant [fc])) => (MOVDconst [b2i(fc.geNoov())])
// absorb InvertFlags into boolean values
(Equal (InvertFlags x)) => (Equal x)

22
src/cmd/compile/internal/ssa/rewriteARM64.go
View File

@ -6182,6 +6182,17 @@ func rewriteValueARM64_OpARM64GreaterEqualNoov(v *Value) bool {
v_0 := v.Args[0]
b := v.Block
typ := &b.Func.Config.Types
// match: (GreaterEqualNoov (FlagConstant [fc]))
// result: (MOVDconst [b2i(fc.geNoov())])
for {
if v_0.Op != OpARM64FlagConstant {
break
}
fc := auxIntToFlagConstant(v_0.AuxInt)
v.reset(OpARM64MOVDconst)
v.AuxInt = int64ToAuxInt(b2i(fc.geNoov()))
return true
}
// match: (GreaterEqualNoov (InvertFlags x))
// result: (CSINC [OpARM64NotEqual] (LessThanNoov <typ.Bool> x) (MOVDconst [0]) x)
for {
@ -6918,6 +6929,17 @@ func rewriteValueARM64_OpARM64LessThanNoov(v *Value) bool {
v_0 := v.Args[0]
b := v.Block
typ := &b.Func.Config.Types
// match: (LessThanNoov (FlagConstant [fc]))
// result: (MOVDconst [b2i(fc.ltNoov())])
for {
if v_0.Op != OpARM64FlagConstant {
break
}
fc := auxIntToFlagConstant(v_0.AuxInt)
v.reset(OpARM64MOVDconst)
v.AuxInt = int64ToAuxInt(b2i(fc.ltNoov()))
return true
}
// match: (LessThanNoov (InvertFlags x))
// result: (CSEL0 [OpARM64NotEqual] (GreaterEqualNoov <typ.Bool> x) x)
for {

36
test/fixedbugs/issue73200.go Normal file
View File

@ -0,0 +1,36 @@
// build
// Copyright 2025 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 main
var g bool
func main() {
l_4 := uint32(0x6E54EE87)
v4 := int8(-Int64FromInt64(1))
g = int32(v4) >= safe_mod_func_int32_t_s_s(BoolInt32(l_4 >= 1), 7)
}
func safe_mod_func_int32_t_s_s(si1 int32, si2 int32) (r int32) {
var v1 int32
if si2 == 0 {
v1 = si1
} else {
v1 = si1 % si2
}
return v1
}
func Int64FromInt64(n int64) int64 {
return n
}
func BoolInt32(b bool) int32 {
if b {
return 1
}
return 0
}