Subzero: Use setcc for most fcmp conditions, instead of control flow.

Subzero: Use setcc for most fcmp conditions, instead of control flow.

For C/C++ semantics, this applies to all the FP comparisons except == and != which require two comparisons due to ordered/unordered requirements.  For == and !=, two comparisons and control flow are still used.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4095
TEST= crosstest/test_fcmp
R=jvoung@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=e94740a0deb3ace2a84dfcd1846af739fb850136

[Jim Stichnoth, 2015-05-22 13:31:48]

stichnot@chromium.org changed reviewers:
+ jvoung@chromium.org, kschimpf@google.com, mtrofin@google.com

[Jim Stichnoth, 2015-05-22 13:40:45]

Not sure if this actually gives speedups, but it's definitely the right thing to
do.

[jvoung (off chromium), 2015-05-22 16:46:48]

LGTM

https://codereview.chromium.org/1148023003/diff/1/src/IceTargetLoweringX8632.cpp
File src/IceTargetLoweringX8632.cpp (right):

https://codereview.chromium.org/1148023003/diff/1/src/IceTargetLoweringX8632....
src/IceTargetLoweringX8632.cpp:2723: _setcc(Dest, TableFcmp[Index].C1);
maybe assert that Default == 1 for this case?

[Jim Stichnoth, 2015-05-22 20:13:00]

https://codereview.chromium.org/1148023003/diff/1/src/IceTargetLoweringX8632.cpp
File src/IceTargetLoweringX8632.cpp (right):

https://codereview.chromium.org/1148023003/diff/1/src/IceTargetLoweringX8632....
src/IceTargetLoweringX8632.cpp:2723: _setcc(Dest, TableFcmp[Index].C1);
On 2015/05/22 16:46:48, jvoung wrote:
> maybe assert that Default == 1 for this case?

Done.

[Jim Stichnoth, 2015-05-22 20:17:38]

Committed patchset #2 (id:20001) manually as
e94740a0deb3ace2a84dfcd1846af739fb850136 (presubmit successful).