Bug 157746 – FixupPhase should be more eager to demote bit math to untyped

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Filip Pizlo]

It shouldn't take a past exit to do it.

[Filip Pizlo]

Created attachment 279034 [details]
the patch

[Mark Lam]

Comment on attachment 279034 [details]
the patch

View in context: https://bugs.webkit.org/attachment.cgi?id=279034&action=review

r=me

> Source/JavaScriptCore/ChangeLog:10
> +        This just makes the logic for how we fixup bit math match the way we do it in other places.
> +        This doesn't affect performance on any major benchmark but it's a big win on new
> +        microbenchmarks added in this change.

Would you mind adding some details for how much gain on the microbenchmarks or aternatively, post the numbers to bugzilla?

[Filip Pizlo]

(In reply to comment #2)
> Comment on attachment 279034 [details]
> the patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=279034&action=review
> 
> r=me
> 
> > Source/JavaScriptCore/ChangeLog:10
> > +        This just makes the logic for how we fixup bit math match the way we do it in other places.
> > +        This doesn't affect performance on any major benchmark but it's a big win on new
> > +        microbenchmarks added in this change.
> 
> Would you mind adding some details for how much gain on the microbenchmarks
> or aternatively, post the numbers to bugzilla?

Added:

        object-and                                     11.1610+-0.7602     ^      4.8105+-0.1690        ^ definitely 2.3201x faster
        object-or                                      11.0845+-0.2487     ^      4.7146+-0.0374        ^ definitely 2.3511x faster
        object-xor                                     10.2946+-0.9946     ^      4.7278+-0.0814        ^ definitely 2.1775x faster
        object-lshift                                  10.4896+-1.0867     ^      4.7699+-0.0721        ^ definitely 2.1991x faster
        object-rshift                                  11.1239+-0.5010     ^      4.7194+-0.0445        ^ definitely 2.3570x faster
        object-urshift                                 10.9745+-0.1315     ^      4.7848+-0.0479        ^ definitely 2.2936x faster

[Filip Pizlo]

Landed in http://trac.webkit.org/changeset/200958