Improve register allocation for Lithium representation changes on ARM...

Improve register allocation for Lithium representation changes on ARM

BUG=none
TEST=none

Committed: https://code.google.com/p/v8/source/detail?r=10538

[danno, 2012-01-16 08:52:59]

generally looks ok to me, but I'd like Florian to take a look since he's more
familiar with the subtleties of the register allocator.

[fschneider, 2012-01-16 12:59:20]

LGMT with one comment to simplify the code slightly.

http://codereview.chromium.org/9207006/diff/1/src/arm/lithium-arm.cc
File src/arm/lithium-arm.cc (right):

http://codereview.chromium.org/9207006/diff/1/src/arm/lithium-arm.cc#newcode1628
src/arm/lithium-arm.cc:1628: LOperand* value;
You can write:

LOperand* value = UseRegisterAtStart(instr->value());

here and the code below will be simpler.

http://codereview.chromium.org/9207006/diff/1/src/arm/lithium-arm.cc#newcode1635
src/arm/lithium-arm.cc:1635: value = UseRegister(instr->value());
In this case you can also use UseRegisterAtStart. When defining the result with
DefineSameAsFirst, UseRegister and UseRegisterAtStart are equivalent for the
first input.

[Alexandre, 2012-01-16 13:07:18]

Thanks for the review.

The updated patch should be uploaded soon.

http://codereview.chromium.org/9207006/diff/1/src/arm/lithium-arm.cc
File src/arm/lithium-arm.cc (right):

http://codereview.chromium.org/9207006/diff/1/src/arm/lithium-arm.cc#newcode1628
src/arm/lithium-arm.cc:1628: LOperand* value;
On 2012/01/16 12:59:20, fschneider wrote:
> You can write:
> 
> LOperand* value = UseRegisterAtStart(instr->value());
> 
> here and the code below will be simpler.

Done.

http://codereview.chromium.org/9207006/diff/1/src/arm/lithium-arm.cc#newcode1635
src/arm/lithium-arm.cc:1635: value = UseRegister(instr->value());
On 2012/01/16 12:59:20, fschneider wrote:
> In this case you can also use UseRegisterAtStart. When defining the result
with
> DefineSameAsFirst, UseRegister and UseRegisterAtStart are equivalent for the
> first input.

Done.

[fschneider, 2012-01-19 10:29:08]

lgtm