ARM: Always use the overflow flag to check for NaNs participating in a floati...

ARM: Always use the overflow flag to check for NaNs participating in a floating point compare.

Looks as if we don't need to use the vcmpe instruction instead of the vcmp, as the overflow FPSCR bit suits our purpose. If we at some point need vcmpe lte's implement it as a separate instruction.

Committed: http://code.google.com/p/v8/source/detail?r=6277

[Karl Klose, 2011-01-11 13:17:48]

LGTM.

[Rodolph Perfetta, 2011-01-11 23:42:26]

http://codereview.chromium.org/6197003/diff/1/src/arm/macro-assembler-arm.cc
File src/arm/macro-assembler-arm.cc (right):

http://codereview.chromium.org/6197003/diff/1/src/arm/macro-assembler-arm.cc#...
src/arm/macro-assembler-arm.cc:552: vmrs(fpscr_flags);
I know this is not part of the change, but the vmrs here should be conditional.
Otherwise LGTM.

http://codereview.chromium.org/6197003/diff/1/src/arm/macro-assembler-arm.cc#...
src/arm/macro-assembler-arm.cc:561: vmrs(fpscr_flags);
Ditto.

[Søren Thygesen Gjesse, 2011-01-12 07:45:46]

http://codereview.chromium.org/6197003/diff/1/src/arm/macro-assembler-arm.cc
File src/arm/macro-assembler-arm.cc (right):

http://codereview.chromium.org/6197003/diff/1/src/arm/macro-assembler-arm.cc#...
src/arm/macro-assembler-arm.cc:552: vmrs(fpscr_flags);
On 2011/01/11 23:42:26, Rodolph Perfetta wrote:
> I know this is not part of the change, but the vmrs here should be
conditional.
> Otherwise LGTM.

Thanks for spotting this - it must have slipped from my previous commit.

http://codereview.chromium.org/6197003/diff/1/src/arm/macro-assembler-arm.cc#...
src/arm/macro-assembler-arm.cc:561: vmrs(fpscr_flags);
On 2011/01/11 23:42:26, Rodolph Perfetta wrote:
> Ditto.

Done.