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cmd/compile: mark LAA and LAAG as clobbering flags on s390x

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The atomic add instructions modify the condition code and so need to
be marked as clobbering flags.

Fixes #24449.

Change-Id: Ic69c8d775fbdbfb2a56c5e0cfca7a49c0d7f6897
Reviewed-on: https://go-review.googlesource.com/101455
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Michael Munday 2018-03-19 13:11:16 -04:00
parent 9c312245ac
commit ae10914e67
3 changed files with 66 additions and 2 deletions
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4
src/cmd/compile/internal/ssa/gen/S390XOps.go
View file

@ -491,8 +491,8 @@ func init() {
// Atomic adds.
// *(arg0+auxint+aux) += arg1. arg2=mem.
// Returns a tuple of <old contents of *(arg0+auxint+aux), memory>.
{name: "LAA", argLength: 3, reg: gpstorelaa, asm: "LAA", typ: "(UInt32,Mem)", aux: "SymOff", faultOnNilArg0: true, hasSideEffects: true, symEffect: "RdWr"},
{name: "LAAG", argLength: 3, reg: gpstorelaa, asm: "LAAG", typ: "(UInt64,Mem)", aux: "SymOff", faultOnNilArg0: true, hasSideEffects: true, symEffect: "RdWr"},
{name: "LAA", argLength: 3, reg: gpstorelaa, asm: "LAA", typ: "(UInt32,Mem)", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true, symEffect: "RdWr"},
{name: "LAAG", argLength: 3, reg: gpstorelaa, asm: "LAAG", typ: "(UInt64,Mem)", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true, symEffect: "RdWr"},
{name: "AddTupleFirst32", argLength: 2}, // arg1=tuple <x,y>. Returns <x+arg0,y>.
{name: "AddTupleFirst64", argLength: 2}, // arg1=tuple <x,y>. Returns <x+arg0,y>.

2
src/cmd/compile/internal/ssa/opGen.go
View file

@ -23541,6 +23541,7 @@ var opcodeTable = [...]opInfo{
name: "LAA",
auxType: auxSymOff,
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
hasSideEffects: true,
symEffect: SymRdWr,
@ -23559,6 +23560,7 @@ var opcodeTable = [...]opInfo{
name: "LAAG",
auxType: auxSymOff,
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
hasSideEffects: true,
symEffect: SymRdWr,

62
test/fixedbugs/issue24449.go Normal file
View file

@ -0,0 +1,62 @@
// run
// Copyright 2018 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
import (
"sync/atomic"
)
var cnt32 int32
//go:noinline
func test32(a, b []int) bool {
// Try to generate flag value, issue atomic
// adds and then re-use the flag value to see if
// the atomic add has clobbered them.
atomic.AddInt32(&cnt32, 1)
if len(a) == len(b) {
atomic.AddInt32(&cnt32, 2)
}
atomic.AddInt32(&cnt32, 4)
if len(a) >= len(b) {
atomic.AddInt32(&cnt32, 8)
}
if len(a) <= len(b) {
atomic.AddInt32(&cnt32, 16)
}
return atomic.LoadInt32(&cnt32) == 31
}
var cnt64 int64
//go:noinline
func test64(a, b []int) bool {
// Try to generate flag value, issue atomic
// adds and then re-use the flag value to see if
// the atomic add has clobbered them.
atomic.AddInt64(&cnt64, 1)
if len(a) == len(b) {
atomic.AddInt64(&cnt64, 2)
}
atomic.AddInt64(&cnt64, 4)
if len(a) >= len(b) {
atomic.AddInt64(&cnt64, 8)
}
if len(a) <= len(b) {
atomic.AddInt64(&cnt64, 16)
}
return atomic.LoadInt64(&cnt64) == 31
}
func main() {
if !test32([]int{}, []int{}) {
panic("test32")
}
if !test64([]int{}, []int{}) {
panic("test64")
}
}