ARM64: use direct conditional branches for regexp

ARM64: use direct conditional branches for regexp

R=ulan@chromium.org, bmeurer@chromium.org

BUG=

[vincent.belliard, 2014-07-03 11:04:32]

With veneers, we can now do direct conditional branches.

If applied with the Adr patch, the total improvement (including the Adr
improvement) is 19% for Sunspider/dna and 7.5% for Octane/regexp.

[ulan, 2014-07-03 11:19:27]

On 2014/07/03 11:04:32, vincent.belliard.arm wrote:
> With veneers, we can now do direct conditional branches.
> 
> If applied with the Adr patch, the total improvement (including the Adr
> improvement) is 19% for Sunspider/dna and 7.5% for Octane/regexp.

lgtm

This is the same as https://codereview.chromium.org/236163006/, where Alexandre
observed ~8% performance penalty on Octane/regexp. So it without the Adr patch
it regresses and with the patch it improves? Or does the improvement come from
something else?

[vincent.belliard, 2014-07-03 11:30:57]

> This is the same as https://codereview.chromium.org/236163006/, where
Alexandre
> observed ~8% performance penalty on Octane/regexp. So it without the Adr patch
> it regresses and with the patch it improves? Or does the improvement come from
> something else?

In this case, Octane/regexp is always improved with this patch but Sunspider/dna
is a very little bit slower with only this patch!

[vincent.belliard, 2014-07-03 13:21:45]

committed r22199