Use xorps xmm1, xmm1 to creat a 0.0 cconstant. Add to utils a bitwise double test.

Use xorps xmm1, xmm1 to creat a 0.0 cconstant. Add to utils a bitwise double test.

R=zra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=35718

[zra, 2014-05-02 23:19:08]

You can do the same on ARM with the veorq instruction.

https://codereview.chromium.org/267793005/diff/1/runtime/platform/utils.h
File runtime/platform/utils.h (right):

https://codereview.chromium.org/267793005/diff/1/runtime/platform/utils.h#new...
runtime/platform/utils.h:184: const int64_t* a_i = reinterpret_cast<const
int64_t*>(&a);
bit_cast<int64_t, double>(a) is what we've been using in the simulators in this
situation, i.e.:

const int64_t a_i = bit_cast<int64_t, double>(a);
const int64_t b_i = bit_cast<int64_t, double>(b);
return (a_i == b_i);

But I guess it probably expands to the same thing.

[srdjan, 2014-05-02 23:33:47]

Added veorq to ARM

https://codereview.chromium.org/267793005/diff/1/runtime/platform/utils.h
File runtime/platform/utils.h (right):

https://codereview.chromium.org/267793005/diff/1/runtime/platform/utils.h#new...
runtime/platform/utils.h:184: const int64_t* a_i = reinterpret_cast<const
int64_t*>(&a);
On 2014/05/02 23:19:08, zra wrote:
> bit_cast<int64_t, double>(a) is what we've been using in the simulators in
this
> situation, i.e.:
> 
> const int64_t a_i = bit_cast<int64_t, double>(a);
> const int64_t b_i = bit_cast<int64_t, double>(b);
> return (a_i == b_i);
> 
> But I guess it probably expands to the same thing.

Done.

[zra, 2014-05-02 23:48:16]

lgtm

[srdjan, 2014-05-02 23:50:30]

Committed patchset #3 manually as r35718 (presubmit successful).