code review 11515045: [release-branch.go1.1] cmd/6g, cmd/8g: prevent constant...

[release-branch.go1.1] cmd/6g, cmd/8g: prevent constant propagation of non-constant LEA.

««« CL 10785043 / cf792c00f410
cmd/6g, cmd/8g: prevent constant propagation of non-constant LEA.

Fixes issue 5809.

R=golang-dev, dave, rsc, nigeltao
CC=golang-dev
https://codereview.appspot.com/10785043
»»»

Update issue 5928

[adg, 2013-07-22 13:46:45]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go

[dave_cheney.net, 2013-07-22 14:30:47]

LGTM. 



On 22/07/2013, at 23:46, adg@golang.org wrote:

> Reviewers: golang-dev1,
> 
> Message:
> Hello golang-dev@googlegroups.com,
> 
> I'd like you to review this change to
> https://code.google.com/p/go
> 
> 
> Description:
> [release-branch.go1.1] cmd/6g, cmd/8g: prevent constant propagation of
> non-constant LEA.
> 
> ««« CL 10785043 / cf792c00f410
> cmd/6g, cmd/8g: prevent constant propagation of non-constant LEA.
> 
> Fixes issue 5809.
> 
> R=golang-dev, dave, rsc, nigeltao
> CC=golang-dev
> https://codereview.appspot.com/10785043
> »»»
> 
> Update issue 5928
> 
> Please review this at https://codereview.appspot.com/11515045/
> 
> Affected files:
>  M src/cmd/6g/peep.c
>  M src/cmd/8g/peep.c
>  A test/fixedbugs/issue5809.go
> 
> 
> Index: src/cmd/6g/peep.c
> ===================================================================
> --- a/src/cmd/6g/peep.c
> +++ b/src/cmd/6g/peep.c
> @@ -152,6 +152,7 @@
>        case ALEAQ:
>            if(regtyp(&p->to))
>            if(p->from.sym != S)
> +            if(p->from.index == D_NONE || p->from.index == D_CONST)
>                conprop(r);
>            break;
> 
> Index: src/cmd/8g/peep.c
> ===================================================================
> --- a/src/cmd/8g/peep.c
> +++ b/src/cmd/8g/peep.c
> @@ -145,6 +145,7 @@
>        case ALEAL:
>            if(regtyp(&p->to))
>            if(p->from.sym != S)
> +            if(p->from.index == D_NONE || p->from.index == D_CONST)
>                conprop(r);
>            break;
> 
> Index: test/fixedbugs/issue5809.go
> ===================================================================
> new file mode 100644
> --- /dev/null
> +++ b/test/fixedbugs/issue5809.go
> @@ -0,0 +1,27 @@
> +// run
> +
> +// Copyright 2013 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 5809: 6g and 8g attempted to constant propagate indexed LEA
> +
> +package main
> +
> +import "fmt"
> +
> +func main() {
> +    const d16 = "0123456789ABCDEF"
> +    k := 0x1234
> +    var x [4]byte
> +    
> +    x[0] = d16[k>>12&0xf]
> +    x[1] = d16[k>>8&0xf]
> +    x[2] = d16[k>>4&0xf]
> +    x[3] = d16[k&0xf]
> +    
> +    if x != [4]byte{'1','2','3','4'} {
> +        fmt.Println(x)
> +        panic("x != [4]byte{'1','2','3','4'}")
> +    }
> +}
> 
> 
> -- 
> 
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> 
> 

[adg, 2013-07-22 22:00:03]

*** Submitted as https://code.google.com/p/go/source/detail?r=3f654997fdd6 ***

[release-branch.go1.1] cmd/6g, cmd/8g: prevent constant propagation of
non-constant LEA.

««« CL 10785043 / cf792c00f410
cmd/6g, cmd/8g: prevent constant propagation of non-constant LEA.

Fixes issue 5809.

R=golang-dev, dave, rsc, nigeltao
CC=golang-dev
https://codereview.appspot.com/10785043
»»»

Update issue 5928

R=golang-dev, dave
CC=golang-dev
https://codereview.appspot.com/11515045