Subzero: Simplify the icmp i64 lowering.

Subzero: Simplify the icmp i64 lowering.

The original code for 64-bit icmp lowering had separate cases for
eq/ne versus other conditions, mostly because eq/ne need two 32-bit
comparisons while the others need three.  However, with small changes,
we can handle everything uniformly, simplifying the code.

This gets thoroughly tested by the test_icmp cross test.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4162
R=jvoung@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=90db6ae07e53badfc9318c219d4d17cd8961e68d

[Jim Stichnoth, 2015-05-06 22:24:15]

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

[Jim Stichnoth, 2015-05-06 22:24:21]

https://codereview.chromium.org/1130023002/diff/1/src/IceTargetLoweringX8632.cpp
File src/IceTargetLoweringX8632.cpp (left):

https://codereview.chromium.org/1130023002/diff/1/src/IceTargetLoweringX8632....
src/IceTargetLoweringX8632.cpp:2724: InstX8632Label *Label =
InstX8632Label::create(Func, this);
This block of code is entirely removed.

https://codereview.chromium.org/1130023002/diff/1/src/IceTargetLoweringX8632....
src/IceTargetLoweringX8632.cpp:2737: _br(TableIcmp64[Index].C1, LabelTrue);
These two branch instructions are now created only when the condition is not
Br_None.

[jvoung (off chromium), 2015-05-07 15:56:58]

lgtm

[Jim Stichnoth, 2015-05-07 16:35:12]

Committed patchset #1 (id:1) manually as
90db6ae07e53badfc9318c219d4d17cd8961e68d (tree was closed).