Fix a bug in the placement of minus-zero checks and in GVN....

Fix a bug in the placement of minus-zero checks and in GVN.

1. The placement of checks for negative zero has to be computed after
all conversion instructions have been inserted. I separated the code
into its own phase.

2. GVN need to take instruction flags into account when comparing
instructions for redundancy.


Committed: http://code.google.com/p/v8/source/detail?r=6534

[William Hesse, 2011-01-31 12:22:54]

Potentially inefficient reallocation.  Otherwise, LGTM.

http://codereview.chromium.org/6260035/diff/1/src/hydrogen.cc
File src/hydrogen.cc (right):

http://codereview.chromium.org/6260035/diff/1/src/hydrogen.cc#newcode1991
src/hydrogen.cc:1991: BitVector visited(GetMaximumValueID());
Is this allocation a problem?  Can you reuse one?

[fschneider, 2011-01-31 12:34:44]

http://codereview.chromium.org/6260035/diff/1/src/hydrogen.cc
File src/hydrogen.cc (right):

http://codereview.chromium.org/6260035/diff/1/src/hydrogen.cc#newcode1991
src/hydrogen.cc:1991: BitVector visited(GetMaximumValueID());
On 2011/01/31 12:22:54, William Hesse wrote:
> Is this allocation a problem?  Can you reuse one?

Good point. Done.

[William Hesse, 2011-01-31 12:35:49]

LGTM.