code review 64370046: cmd/gc: avoid pointer beyond array in range loop

cmd/gc: avoid pointer beyond array in range loop

This problem was discovered by reading the code.
I have not seen it in practice, nor do I have any ideas
on how to trigger it reliably in a test. But it's still worth
fixing.

[rsc, 2014-02-16 01:00:55]

Hello ken2 (cc: golang-codereviews@googlegroups.com),

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

[rsc, 2014-02-16 01:01:00]

*** Submitted as https://code.google.com/p/go/source/detail?r=2379f812d6b8 ***

cmd/gc: avoid pointer beyond array in range loop

This problem was discovered by reading the code.
I have not seen it in practice, nor do I have any ideas
on how to trigger it reliably in a test. But it's still worth
fixing.

TBR=ken2
CC=golang-codereviews
https://codereview.appspot.com/64370046

[gobot, 2014-02-16 02:07:08]

This CL appears to have broken the darwin-amd64 builder.

[mtj1, 2014-02-16 06:09:00]

FWIW, you could instead do:

if(i >= len(x)-1) break; p++; i++;

or

i++; if(i >= len(x)) break; p++;

and p would never point beyond the slice.
On Feb 15, 2014 6:07 PM, <gobot@golang.org> wrote:

> This CL appears to have broken the darwin-amd64 builder.
>
> https://codereview.appspot.com/64370046/
>
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