Fix corner cases for double pow operation.

Fix corner cases for double pow operation.

R=regis@google.com, zra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=26662

[zra, 2013-08-23 22:43:03]

lgtm

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4136:
result->AddTemp(Location::RegisterLocation(R2));
Why does this have to be R2? I think you can use TMP instead of reserving
another temporary unless Double::value_offset() is so big that LoadDFromOffset
will need it.

[srdjan, 2013-08-23 23:26:04]

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4136:
result->AddTemp(Location::RegisterLocation(R2));
On 2013/08/23 22:43:03, zra wrote:
> Why does this have to be R2? I think you can use TMP instead of reserving
> another temporary unless Double::value_offset() is so big that LoadDFromOffset
> will need it.

The IP is used because the offset is not 4-byte aligned (11).

[regis, 2013-08-26 17:03:26]

LGTM with 2 suggestions.

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4148: // if (exponent == 0.0) return
0.0;
I would add a comment like this, otherwise it looks like some code is commented
out:
// Pseudo code:

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4175: __ b(&base_is_nan, VS);
Instead of:
__ b(&base_is_nan, VS);
and
__ Bind(&base_is_nan);
__ vmovd(result, saved_base);  // base is NaN, return NaN.
__ b(&skip_call);

you can do:
__ vmovd(result, saved_base, VS);  // base is NaN, return NaN.
__ b(&skip_call, VS);

this way, you can remove the base_is_nan label, the do_call label, the __
b(&do_call) and the else part.

[srdjan, 2013-08-26 17:24:00]

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4148: // if (exponent == 0.0) return
0.0;
On 2013/08/26 17:03:26, regis wrote:
> I would add a comment like this, otherwise it looks like some code is
commented
> out:
> // Pseudo code:

Done.

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4175: __ b(&base_is_nan, VS);
On 2013/08/26 17:03:26, regis wrote:
> Instead of:
> __ b(&base_is_nan, VS);
> and
> __ Bind(&base_is_nan);
> __ vmovd(result, saved_base);  // base is NaN, return NaN.
> __ b(&skip_call);
> 
> you can do:
> __ vmovd(result, saved_base, VS);  // base is NaN, return NaN.
> __ b(&skip_call, VS);
> 
> this way, you can remove the base_is_nan label, the do_call label, the __
> b(&do_call) and the else part.

Done.

[srdjan, 2013-08-26 17:24:00]

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4148: // if (exponent == 0.0) return
0.0;
On 2013/08/26 17:03:26, regis wrote:
> I would add a comment like this, otherwise it looks like some code is
commented
> out:
> // Pseudo code:

Done.

https://codereview.chromium.org/23072044/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:4175: __ b(&base_is_nan, VS);
On 2013/08/26 17:03:26, regis wrote:
> Instead of:
> __ b(&base_is_nan, VS);
> and
> __ Bind(&base_is_nan);
> __ vmovd(result, saved_base);  // base is NaN, return NaN.
> __ b(&skip_call);
> 
> you can do:
> __ vmovd(result, saved_base, VS);  // base is NaN, return NaN.
> __ b(&skip_call, VS);
> 
> this way, you can remove the base_is_nan label, the do_call label, the __
> b(&do_call) and the else part.

Done.

[srdjan, 2013-08-26 17:39:04]

Committed patchset #2 manually as r26662 (presubmit successful).