Handle imul, pcmpeq, pcmpgt.

Handle imul, pcmpeq, pcmpgt.

Be sure to legalize 8-bit imul immediates (there is only the r/m form).
Add a test for that, and cover a couple of other ops too...

There is a one-byte-shorter form when Dest/Src0 == EAX and Src1 is not
an immediate, but that isn't taken advantage of.

Go ahead and add the optimization for 8-bit immediates for i16/i32
(not allowed for i8). It shows up sometimes in spec, e.g., to multiply by 10.
There is a lot of multiply by 4 as well, that we could strength-reduce.

BUG=none
R=stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=0ac50dcfc0b5d67663265e24a030b0d180f690e5

[jvoung (off chromium), 2014-09-29 23:02:44]

jvoung@chromium.org changed reviewers:
+ stichnot@chromium.org

[Jim Stichnoth, 2014-09-30 05:17:07]

lgtm

https://codereview.chromium.org/617593002/diff/20001/src/IceTargetLoweringX86...
File src/IceTargetLoweringX8632.cpp (right):

https://codereview.chromium.org/617593002/diff/20001/src/IceTargetLoweringX86...
src/IceTargetLoweringX8632.cpp:1586: Src1 = legalize(Src1, Legal_Reg |
Legal_Mem);
cool, thanks!

[jvoung (off chromium), 2014-09-30 15:36:11]

Committed patchset #2 (id:20001) manually as
0ac50dcfc0b5d67663265e24a030b0d180f690e5 (presubmit successful).