Experimental: when doing memory-to-memory moves as part of a frame...

Experimental: when doing memory-to-memory moves as part of a frame
merge, use the esi register (already saved in the frame) rather than
allocating and possibly spilling some other register.

Also, implement equality predicate on frames for debug assertions
(fixing issue 208, http://code.google.com/p/v8/issues/detail?id=208 ).

Committed: http://code.google.com/p/v8/source/detail?r=1251

[William Hesse, 2009-02-11 09:46:47]

http://codereview.chromium.org/20257/diff/1/2
File src/virtual-frame-ia32.cc (right):

http://codereview.chromium.org/20257/diff/1/2#newcode666
Line 666: if (source.is_register() && target.is_register()) {
What is the precondition on the frame and expected frame re. copies, for MergeTo
to work?  We are clearly not handling all cases of copies here, are we?

http://codereview.chromium.org/20257/diff/1/2#newcode795
Line 795: EmitPush(esi);
I didn't know we were keeping EmitPush().  Which of the functions used while
converting to unspilled frames are we going to keep?

[William Hesse, 2009-02-11 12:44:21]

LGTM