Subzero: Fix sign issues for inlined memset lowering.

Subzero: Fix sign issues for inlined memset lowering.

For certain cases of inlined memset lowering, the 8-bit value wasn't being properly spread/replicated into the 32-bit immediate to be stored.

Specifically, if the 8-bit value is between -128 and -1 (i.e. 0x80 to 0xff), the spread value would be something like 0xffffff80 instead of 0x80808080.

BUG= b/30502279
R=jpp@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=59ce615334de49a062aa40f34232890458b8770d

[Jim Stichnoth, 2016-08-04 01:52:17]

Description was changed from

==========
Subzero: Fix sign issues for inlined memset lowering.

BUG= none
==========

to

==========
Subzero: Fix sign issues for inlined memset lowering.

For certain cases of inlined memset lowering, the 8-bit value wasn't being
properly spread/replicated into the 32-bit immediate to be stored.

Specifically, if the 8-bit value is between -128 and -1 (i.e. 0x80 to 0xff), the
spread value would be something like 0xffffff80 instead of 0x80808080.

BUG= b/30502279
==========

[Jim Stichnoth, 2016-08-04 01:52:17]

stichnot@chromium.org changed reviewers:
+ eholk@chromium.org, jpp@chromium.org, kschimpf@google.com

[John, 2016-08-04 13:47:50]

lgtm

[Jim Stichnoth, 2016-08-04 14:03:00]

Description was changed from

==========
Subzero: Fix sign issues for inlined memset lowering.

For certain cases of inlined memset lowering, the 8-bit value wasn't being
properly spread/replicated into the 32-bit immediate to be stored.

Specifically, if the 8-bit value is between -128 and -1 (i.e. 0x80 to 0xff), the
spread value would be something like 0xffffff80 instead of 0x80808080.

BUG= b/30502279
==========

to

==========
Subzero: Fix sign issues for inlined memset lowering.

For certain cases of inlined memset lowering, the 8-bit value wasn't being
properly spread/replicated into the 32-bit immediate to be stored.

Specifically, if the 8-bit value is between -128 and -1 (i.e. 0x80 to 0xff), the
spread value would be something like 0xffffff80 instead of 0x80808080.

BUG= b/30502279
R=jpp@chromium.org

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

[Jim Stichnoth, 2016-08-04 14:03:01]

Committed patchset #1 (id:1) manually as
59ce615334de49a062aa40f34232890458b8770d (presubmit successful).