MIPS: Some assembler-level optimizations on ARM.

MIPS: Some assembler-level optimizations on ARM.

Port r10541 (0aab14ba).

BUG=
TEST=

Committed: https://code.google.com/p/v8/source/detail?r=10568

[kalmard, 2012-01-30 13:17:36]

This patch can be applied after landing http://codereview.chromium.org/9296045/

[Yang, 2012-01-30 14:12:29]

LGTM, but I personally don't see the need for those changes.  The reordering of
loads were done to avoid wasting time on memory loads that stalls a few cycles.
I suspect that MIPS processors show similar behavior, so that's fine.  The
changes to UntagAndJumpIf(Not)Smi however make no sense on MIPS, as it saves no
instructions and in some occasions might even worsens the performance.

[Yang, 2012-01-30 14:30:40]

On 2012/01/30 14:12:29, Yang wrote:
> LGTM, but I personally don't see the need for those changes.  The reordering
of
> loads were done to avoid wasting time on memory loads that stalls a few
cycles.
> I suspect that MIPS processors show similar behavior, so that's fine.  The
> changes to UntagAndJumpIf(Not)Smi however make no sense on MIPS, as it saves
no
> instructions and in some occasions might even worsens the performance.

Nevermind. I forgot about the delay slot. I will land this after
http://codereview.chromium.org/9296045/

[kalmard, 2012-01-31 12:20:29]

rebased on r10562