Fix math min/max for -0.0 case. Enable min_max_test to run in optimizing compiler as well.

Fix math min/max for -0.0 case. Enable min_max_test to run in optimizing compiler as well.

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

Committed: https://code.google.com/p/dart/source/detail?r=25306

[zra, 2013-07-22 20:35:53]

lgtm

lgtm

[regis, 2013-07-22 20:55:10]

LGTM with suggestions for ARM and MIPS.

https://codereview.chromium.org/19482023/diff/1/runtime/vm/constants_mips.h
File runtime/vm/constants_mips.h (right):

https://codereview.chromium.org/19482023/diff/1/runtime/vm/constants_mips.h#n...
runtime/vm/constants_mips.h:158: static inline FRegister
OddFRegisterOf(DRegister d) {
Implementing only OddFRegisterOf is ... odd.
Why not add EvenFRegisterOf, even [sic] if it is not used? Just for clarity.

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:3405: __ tst(temp, ShifterOperand(1)); 
// NE -> is negative.
You do not need to sign extend to test the sign bit. A single instruction is
enough:
__ cmp(temp, ShifterOperand(0));
The use LT and GE as conditions.

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_mips.cc (right):

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_mips.cc:3148: __ andi(CMPRES, temp,
Immediate(1));  // Check if the bit is set.
You do not need the 2 instructions above. Use bltz for the conditional branch
below.

[srdjan, 2013-07-22 21:10:15]

https://codereview.chromium.org/19482023/diff/1/runtime/vm/constants_mips.h
File runtime/vm/constants_mips.h (right):

https://codereview.chromium.org/19482023/diff/1/runtime/vm/constants_mips.h#n...
runtime/vm/constants_mips.h:158: static inline FRegister
OddFRegisterOf(DRegister d) {
On 2013/07/22 20:55:11, regis wrote:
> Implementing only OddFRegisterOf is ... odd.
> Why not add EvenFRegisterOf, even [sic] if it is not used? Just for clarity.

Done.

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_arm.cc:3405: __ tst(temp, ShifterOperand(1)); 
// NE -> is negative.
On 2013/07/22 20:55:11, regis wrote:
> You do not need to sign extend to test the sign bit. A single instruction is
> enough:
> __ cmp(temp, ShifterOperand(0));
> The use LT and GE as conditions.

Done.

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_mips.cc (right):

https://codereview.chromium.org/19482023/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_mips.cc:3148: __ andi(CMPRES, temp,
Immediate(1));  // Check if the bit is set.
On 2013/07/22 20:55:11, regis wrote:
> You do not need the 2 instructions above. Use bltz for the conditional branch
> below.

Done.

[srdjan, 2013-07-22 21:37:49]

Committed patchset #2 manually as r25306 (presubmit successful).

[sra1, 2013-07-22 22:10:59]

https://codereview.chromium.org/19482023/diff/10001/runtime/vm/intermediate_l...
File runtime/vm/intermediate_language_ia32.cc (right):

https://codereview.chromium.org/19482023/diff/10001/runtime/vm/intermediate_l...
runtime/vm/intermediate_language_ia32.cc:3687: // -0.0 or 0.0 respectively.
Both are equal, so are the same bits except +0.0/-0.0
The only difference is the sign bit.
Bitwise OR for min, bitwise AND for max.
Pity there is no ANDSD instruction, but ANDPD might be faster and more compact
that this code.