Add static analysis to AST expressions that records whether a negative zero w...

Add static analysis to AST expressions that records whether a negative zero will be treated identically to a positive zero in the expression's context.  Use this flag to avoid some tests in inlined smi code.

Committed: http://code.google.com/p/v8/source/detail?r=4130

[William Hesse, 2010-03-15 11:43:19]

A later change will change all the CodeGenerator:: binary operation
implementations to take an AST BinaryOperation node, rather than passing all the
information as separate parameters.

[fschneider, 2010-03-15 13:51:29]

LGTM otherwise.

http://codereview.chromium.org/965001/diff/1/2
File src/ia32/codegen-ia32.cc (right):

http://codereview.chromium.org/965001/diff/1/2#newcode1927
src/ia32/codegen-ia32.cc:1927: overwrite_mode, false);
Why pass false here? Should it be no_negative_zero as well?

http://codereview.chromium.org/965001/diff/1/2#newcode1963
src/ia32/codegen-ia32.cc:1963: overwrite_mode, false);
Why pass false here? Should it be no_negative_zero as well?

http://codereview.chromium.org/965001/diff/1/5
File src/rewriter.cc (right):

http://codereview.chromium.org/965001/diff/1/5#newcode580
src/rewriter.cc:580: node->right()->set_no_negative_zero(true);  // Only
[[HasIntance]] gets it.
Typo in comment ->HasInstance

[William Hesse, 2010-03-15 14:01:49]

All comments fixed.

On 2010/03/15 13:51:29, fschneider wrote:
> LGTM otherwise.
> 
> http://codereview.chromium.org/965001/diff/1/2
> File src/ia32/codegen-ia32.cc (right):
> 
> http://codereview.chromium.org/965001/diff/1/2#newcode1927
> src/ia32/codegen-ia32.cc:1927: overwrite_mode, false);
> Why pass false here? Should it be no_negative_zero as well?
> 
> http://codereview.chromium.org/965001/diff/1/2#newcode1963
> src/ia32/codegen-ia32.cc:1963: overwrite_mode, false);
> Why pass false here? Should it be no_negative_zero as well?
> 
> http://codereview.chromium.org/965001/diff/1/5
> File src/rewriter.cc (right):
> 
> http://codereview.chromium.org/965001/diff/1/5#newcode580
> src/rewriter.cc:580: node->right()->set_no_negative_zero(true);  // Only
> [[HasIntance]] gets it.
> Typo in comment ->HasInstance