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cmd/compile: fix rewrite rules for multiply/add 

x - (y - c) == (x - y) + c, not (x - y) - c. Oops.

Fixes #70481

Change-Id: I0e54d8e65dd9843c6b92c543ac69d69ee21f617c
Reviewed-on: https://go-review.googlesource.com/c/go/+/630397
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Jakub Ciolek <jakub@ciolek.dev>
Auto-Submit: Keith Randall <khr@golang.org>
This commit is contained in:
Keith Randall 2024-11-20 17:48:30 -08:00 committed by David Chase
parent 3ff868f2f5
commit 0a0a7a5642
4 changed files with 57 additions and 18 deletions
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4
src/cmd/compile/internal/ssa/_gen/ARM64.rules
View File

@ -1150,8 +1150,8 @@
// madd/msub can't take constant arguments, so do a bit of reordering if a non-constant is available. // madd/msub can't take constant arguments, so do a bit of reordering if a non-constant is available.
(ADD a p:(ADDconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (ADDconst [c] (ADD <v.Type> a m)) (ADD a p:(ADDconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (ADDconst [c] (ADD <v.Type> a m))
(ADD a p:(SUBconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (SUBconst [c] (ADD <v.Type> a m)) (ADD a p:(SUBconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (SUBconst [c] (ADD <v.Type> a m))
(SUB a p:(ADDconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (ADDconst [c] (SUB <v.Type> a m)) (SUB a p:(ADDconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (SUBconst [c] (SUB <v.Type> a m))
(SUB a p:(SUBconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (SUBconst [c] (SUB <v.Type> a m)) (SUB a p:(SUBconst [c] m:((MUL|MULW|MNEG|MNEGW) _ _))) && p.Uses==1 && m.Uses==1 => (ADDconst [c] (SUB <v.Type> a m))
// optimize ADCSflags, SBCSflags and friends // optimize ADCSflags, SBCSflags and friends
(ADCSflags x y (Select1 <types.TypeFlags> (ADDSconstflags [-1] (ADCzerocarry <typ.UInt64> c)))) => (ADCSflags x y c) (ADCSflags x y (Select1 <types.TypeFlags> (ADDSconstflags [-1] (ADCzerocarry <typ.UInt64> c)))) => (ADCSflags x y c)

32
src/cmd/compile/internal/ssa/rewriteARM64.go
View File

@ -16606,7 +16606,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(ADDconst [c] m:(MUL _ _))) // match: (SUB a p:(ADDconst [c] m:(MUL _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (ADDconst [c] (SUB <v.Type> a m)) // result: (SUBconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16618,7 +16618,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MUL || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MUL || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64ADDconst) v.reset(OpARM64SUBconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)
@ -16627,7 +16627,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(ADDconst [c] m:(MULW _ _))) // match: (SUB a p:(ADDconst [c] m:(MULW _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (ADDconst [c] (SUB <v.Type> a m)) // result: (SUBconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16639,7 +16639,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MULW || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MULW || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64ADDconst) v.reset(OpARM64SUBconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)
@ -16648,7 +16648,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(ADDconst [c] m:(MNEG _ _))) // match: (SUB a p:(ADDconst [c] m:(MNEG _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (ADDconst [c] (SUB <v.Type> a m)) // result: (SUBconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16660,7 +16660,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MNEG || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MNEG || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64ADDconst) v.reset(OpARM64SUBconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)
@ -16669,7 +16669,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(ADDconst [c] m:(MNEGW _ _))) // match: (SUB a p:(ADDconst [c] m:(MNEGW _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (ADDconst [c] (SUB <v.Type> a m)) // result: (SUBconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16681,7 +16681,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MNEGW || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MNEGW || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64ADDconst) v.reset(OpARM64SUBconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)
@ -16690,7 +16690,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(SUBconst [c] m:(MUL _ _))) // match: (SUB a p:(SUBconst [c] m:(MUL _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (SUBconst [c] (SUB <v.Type> a m)) // result: (ADDconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16702,7 +16702,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MUL || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MUL || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64SUBconst) v.reset(OpARM64ADDconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)
@ -16711,7 +16711,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(SUBconst [c] m:(MULW _ _))) // match: (SUB a p:(SUBconst [c] m:(MULW _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (SUBconst [c] (SUB <v.Type> a m)) // result: (ADDconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16723,7 +16723,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MULW || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MULW || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64SUBconst) v.reset(OpARM64ADDconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)
@ -16732,7 +16732,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(SUBconst [c] m:(MNEG _ _))) // match: (SUB a p:(SUBconst [c] m:(MNEG _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (SUBconst [c] (SUB <v.Type> a m)) // result: (ADDconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16744,7 +16744,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MNEG || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MNEG || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64SUBconst) v.reset(OpARM64ADDconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)
@ -16753,7 +16753,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
} }
// match: (SUB a p:(SUBconst [c] m:(MNEGW _ _))) // match: (SUB a p:(SUBconst [c] m:(MNEGW _ _)))
// cond: p.Uses==1 && m.Uses==1 // cond: p.Uses==1 && m.Uses==1
// result: (SUBconst [c] (SUB <v.Type> a m)) // result: (ADDconst [c] (SUB <v.Type> a m))
for { for {
a := v_0 a := v_0
p := v_1 p := v_1
@ -16765,7 +16765,7 @@ func rewriteValueARM64_OpARM64SUB(v *Value) bool {
if m.Op != OpARM64MNEGW || !(p.Uses == 1 && m.Uses == 1) { if m.Op != OpARM64MNEGW || !(p.Uses == 1 && m.Uses == 1) {
break break
} }
v.reset(OpARM64SUBconst) v.reset(OpARM64ADDconst)
v.AuxInt = int64ToAuxInt(c) v.AuxInt = int64ToAuxInt(c)
v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type) v0 := b.NewValue0(v.Pos, OpARM64SUB, v.Type)
v0.AddArg2(a, m) v0.AddArg2(a, m)

20
test/fixedbugs/issue70481.go Normal file
View File

@ -0,0 +1,20 @@
// run
// Copyright 2024 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
const maxUint64 = (1 << 64) - 1
//go:noinline
func f(n uint64) uint64 {
return maxUint64 - maxUint64%n
}
func main() {
for i := uint64(1); i < 20; i++ {
println(i, maxUint64-f(i))
}
}

19
test/fixedbugs/issue70481.out Normal file
View File

@ -0,0 +1,19 @@
1 0
2 1
3 0
4 3
5 0
6 3
7 1
8 7
9 6
10 5
11 4
12 3
13 2
14 1
15 0
16 15
17 0
18 15
19 16