Port code to load an integer directly from a heap number from ia32 to x64....

Port code to load an integer directly from a heap number from ia32 to x64.

For now, this is a direct port from ia32, so there is probably still
stuff that can be improved here.

Committed: http://code.google.com/p/v8/source/detail?r=3717

[Erik Corry, 2010-01-27 13:16:01]

LGTM

http://codereview.chromium.org/555131/diff/10/3004
File src/x64/codegen-x64.cc (right):

http://codereview.chromium.org/555131/diff/10/3004#newcode6323
src/x64/codegen-x64.cc:6323: // Load rcx with zero.  We use this either for the
final shift or
All this stuff could probably be reimplemented in a simpler way loading the
whole double into a 64 bit register.  On the other hand almost all 64 bit
processors have SSE3 so it's hardly worth it.

http://codereview.chromium.org/555131/diff/10/3004#newcode7493
src/x64/codegen-x64.cc:7493: __ Cmp(rdx, Factory::undefined_value());
You should use CompareRoot here.  It's a tiny bit faster and somewhat more
compact.  That applies to the other uses of Cmp too.

[Mads Ager (chromium), 2010-01-27 13:33:34]

http://codereview.chromium.org/555131/diff/10/3004
File src/x64/codegen-x64.cc (right):

http://codereview.chromium.org/555131/diff/10/3004#newcode6323
src/x64/codegen-x64.cc:6323: // Load rcx with zero.  We use this either for the
final shift or
On 2010/01/27 13:16:01, Erik Corry wrote:
> All this stuff could probably be reimplemented in a simpler way loading the
> whole double into a 64 bit register.  On the other hand almost all 64 bit
> processors have SSE3 so it's hardly worth it.

I agree.

http://codereview.chromium.org/555131/diff/10/3004#newcode7493
src/x64/codegen-x64.cc:7493: __ Cmp(rdx, Factory::undefined_value());
On 2010/01/27 13:16:01, Erik Corry wrote:
> You should use CompareRoot here.  It's a tiny bit faster and somewhat more
> compact.  That applies to the other uses of Cmp too.

I always forget that - thanks for pointing it out every time. :)

Done.