Re: Improves performance for calls from Crankshaft code to certain string and... (issue 10996065)

[yan...@chromium.org]

On 2012/10/12 15:51:15, danno wrote:
> Whoops, hit the wrong button. This doesn't look good to me on this patch
> quite
> yet,

A quick test shows that this patch causes the V8 benchmark bundled in the V8
repository (benchmark/run.js) to crash with segfaults (RayTrace and RegExp).

This patch seems to attempt to improve V8's performance for string and
regexp
operations when the result is not used. I expect this to be very rare in
actual
javascript applications (why would you run an expensive string/regexp
operation
when you don't use its result?).
However, V8's RegExp benchmark contains a lot of those operations with
unused
results. This has been a known fact and there are plans (see 10913269) to
change
that so that this benchmark tests what it's intended to test
(https://chromiumcodereview.appspot.com/10913269/). That's why I think this
patch is taking the wrong direction.

http://codereview.chromium.org/10996065/