[JSC] Speed up the coalescing-related operation of the iterated register allocator

• Component: New Bugs
• Status: RESOLVED FIXED

[Benjamin Poulain]

[JSC] Speed up the coalescing-related operation of the iterated register allocator

[Benjamin Poulain]

Created attachment 265530 [details]
Patch

[Geoffrey Garen]

Comment on attachment 265530 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=265530&action=review

r=me

Is this a speedup?

> Source/JavaScriptCore/b3/air/AirIteratedRegisterCoalescing.cpp:760
> +    // in the vector has the "identifier" for the move.

as

> Source/JavaScriptCore/b3/air/AirIteratedRegisterCoalescing.cpp:781
> +    struct OrderedMoveSet {

Can this go in its own file?

> Source/JavaScriptCore/b3/air/AirIteratedRegisterCoalescing.cpp:797
> +            return m_positionInMoveList[index] != std::numeric_limits<unsigned>::max();

Let's use wtf::notFound.

> Source/JavaScriptCore/b3/air/AirIteratedRegisterCoalescing.cpp:831
> +            // This assertion is a bit strict but that how the move list should be used. The only kind of moves that can

that is

> Source/JavaScriptCore/b3/air/AirIteratedRegisterCoalescing.cpp:832
> +            // return to the list are the one that we previous failed to coalesced with the conservative heuristics.

the ones
previously
to coalesce

[Benjamin Poulain]

Created attachment 265611 [details]
Patch for landing

[Benjamin Poulain]

(In reply to comment #2)
> r=me
> 
> Is this a speedup?

Quite a bit, yep. Globally, it is 2%.

> > Source/JavaScriptCore/b3/air/AirIteratedRegisterCoalescing.cpp:781
> > +    struct OrderedMoveSet {
> 
> Can this go in its own file?

If I need a generic version, I'll make a new file.

Here, OrderedMoveSet knows exactly how it is supposed to be used. IMHO, it is better to keep the code close.

[Benjamin Poulain]

Comment on attachment 265611 [details]
Patch for landing

Clearing flags on attachment: 265611

Committed r192492: <http://trac.webkit.org/changeset/192492>

[Benjamin Poulain]

All reviewed patches have been landed.  Closing bug.

[WebKit Commit Bot]

Re-opened since this is blocked by bug 151330