On Tue, Oct 4, 2011 at 10:06 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
>>> This patch improves address combine for x32 by forcing the memory memory
>>> operand of PLUS operation into register. Tested on Linux/x86-64 with
>>> -mx32. OK for trunk?
>>
>> Does the patch fix
>>
>> FAIL: gcc.target/i386/pr45670.c scan-assembler-not lea[lq]
>>
>> on x32 ?
>
> It does.
>
> Following patch is the same, but takes into account that non-matching
> memory can only be in src2, so it avoids a bunch of unnecessary
> checks. Can you please check the effects of the patch with some
> codesize benchmark?
OTOH, x86_64 and i686 targets can also benefit from this change. If
combine can't create more complex address (covered by lea), then it
will simply propagate memory operand back into the add insn. It looks
to me that we can't loose here, so:
/* Improve address combine. */
if (code == PLUS && MEM_P (src2))
src2 = force_reg (mode, src2);
Any opinions?
Uros.
