mirror of
https://github.com/golang/go
synced 2024-11-18 13:34:41 -07:00
93b7eb973f
Load/store-merging and move optimizations can result in unaligned memory accesses. This is fine so long as the load/store instruction used does not take a relative offset. In the SSA rules this means we must not merge (MOVDaddr (SB)) ops into loads/stores unless we can guarantee the alignment of the target. Fixes #21048. Change-Id: I70f13a62a148d5f0a56e704e8f76e36b4a4226d9 Reviewed-on: https://go-review.googlesource.com/49250 Run-TryBot: Michael Munday <mike.munday@ibm.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
73 lines
1.1 KiB
Go
73 lines
1.1 KiB
Go
// run
|
|
|
|
// Copyright 2017 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.
|
|
|
|
// Issue 21048: s390x merged address generation into stores
|
|
// to unaligned global variables. This resulted in an illegal
|
|
// instruction.
|
|
|
|
package main
|
|
|
|
type T struct {
|
|
_ [1]byte
|
|
a [2]byte // offset: 1
|
|
_ [3]byte
|
|
b [2]uint16 // offset: 6
|
|
_ [2]byte
|
|
c [2]uint32 // offset: 12
|
|
_ [2]byte
|
|
d [2]int16 // offset: 22
|
|
_ [2]byte
|
|
e [2]int32 // offset: 28
|
|
}
|
|
|
|
var Source, Sink T
|
|
|
|
func newT() T {
|
|
return T{
|
|
a: [2]byte{1, 2},
|
|
b: [2]uint16{1, 2},
|
|
c: [2]uint32{1, 2},
|
|
d: [2]int16{1, 2},
|
|
e: [2]int32{1, 2},
|
|
}
|
|
}
|
|
|
|
//go:noinline
|
|
func moves() {
|
|
Sink.a = Source.a
|
|
Sink.b = Source.b
|
|
Sink.c = Source.c
|
|
Sink.d = Source.d
|
|
Sink.e = Source.e
|
|
}
|
|
|
|
//go:noinline
|
|
func loads() *T {
|
|
t := newT()
|
|
t.a = Source.a
|
|
t.b = Source.b
|
|
t.c = Source.c
|
|
t.d = Source.d
|
|
t.e = Source.e
|
|
return &t
|
|
}
|
|
|
|
//go:noinline
|
|
func stores() {
|
|
t := newT()
|
|
Sink.a = t.a
|
|
Sink.b = t.b
|
|
Sink.c = t.c
|
|
Sink.d = t.d
|
|
Sink.e = t.e
|
|
}
|
|
|
|
func main() {
|
|
moves()
|
|
loads()
|
|
stores()
|
|
}
|