Fixing MathPowHalf on ARM.

Fixing MathPowHalf on ARM.

BUG=v8:397
TEST=regress-397.js

Committed: http://code.google.com/p/v8/source/detail?r=10166

[Yang, 2011-12-05 15:52:22]

PTAL.

[Rodolph Perfetta, 2011-12-05 17:38:36]

http://codereview.chromium.org/8800009/diff/3001/src/arm/lithium-codegen-arm.cc
File src/arm/lithium-codegen-arm.cc (right):

http://codereview.chromium.org/8800009/diff/3001/src/arm/lithium-codegen-arm....
src/arm/lithium-codegen-arm.cc:3106: __ vcmp(input, result);
Confusingly on ARM vcmp does no set the flags! you need a vmrs into pc
afterwards.
There is a macro in the macro-assembler for this:
VPCompareAndSetFlags

[Yang, 2011-12-05 18:05:41]

On 2011/12/05 17:38:36, Rodolph Perfetta wrote:
>
http://codereview.chromium.org/8800009/diff/3001/src/arm/lithium-codegen-arm.cc
> File src/arm/lithium-codegen-arm.cc (right):
> 
>
http://codereview.chromium.org/8800009/diff/3001/src/arm/lithium-codegen-arm....
> src/arm/lithium-codegen-arm.cc:3106: __ vcmp(input, result);
> Confusingly on ARM vcmp does no set the flags! you need a vmrs into pc
> afterwards.
> There is a macro in the macro-assembler for this:
> VPCompareAndSetFlags

Thanks for the hint! I fixed this and added tests.

[Sven Panne, 2011-12-06 08:23:12]

LGTM with a minor nit

http://codereview.chromium.org/8800009/diff/1002/src/arm/lithium-codegen-arm.cc
File src/arm/lithium-codegen-arm.cc (right):

http://codereview.chromium.org/8800009/diff/1002/src/arm/lithium-codegen-arm....
src/arm/lithium-codegen-arm.cc:3105: __ VFPCompareAndSetFlags(input, -INFINITY);
I think we should use V8_INFINITY here, although I don't fully understand the
rationale behind our #ifdef magic for this constant...