[turbofan] Fixes the code generation for branches on x64 when the condition is Word64Equal.

[turbofan] Fixes the code generation for branches on x64 when the condition is Word64Equal.

Before:

REX.W cmpq r9,r8
setzl r8l
movzxbl r8,r8
REX.W cmpq r8,0x0
jz 185

After:

REX.W cmpq r9,r8
jnz 149

Committed: https://crrev.com/75cc8352d06aada2e9131fdae793299ef73fb639
Cr-Commit-Position: refs/heads/master@{#33784}

[epertoso, 2016-02-05 14:28:44]

epertoso@chromium.org changed reviewers:
+ bmeurer@chromium.org

[epertoso, 2016-02-05 14:28:44]

epertoso@chromium.org changed required reviewers:
+ bmeurer@chromium.org

[Benedikt Meurer, 2016-02-05 14:29:54]

Nice catch! LGTM

[Benedikt Meurer, 2016-02-05 14:30:08]

Description was changed from

==========
Fixes the code generation for branches on x64 when the condition is Word64Equal.

Before:

REX.W cmpq r9,r8
setzl r8l
movzxbl r8,r8
REX.W cmpq r8,0x0
jz 185

After:

REX.W cmpq r9,r8
jnz 149


BUG=
==========

to

==========
[turbofan] Fixes the code generation for branches on x64 when the condition is
Word64Equal.

Before:

REX.W cmpq r9,r8
setzl r8l
movzxbl r8,r8
REX.W cmpq r8,0x0
jz 185

After:

REX.W cmpq r9,r8
jnz 149
==========

[epertoso, 2016-02-05 14:30:44]

The CQ bit was checked by epertoso@chromium.org

[commit-bot: I haz the power, 2016-02-05 14:30:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1677503002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1677503002/1

[commit-bot: I haz the power, 2016-02-05 15:00:54]

Description was changed from

==========
[turbofan] Fixes the code generation for branches on x64 when the condition is
Word64Equal.

Before:

REX.W cmpq r9,r8
setzl r8l
movzxbl r8,r8
REX.W cmpq r8,0x0
jz 185

After:

REX.W cmpq r9,r8
jnz 149
==========

to

==========
[turbofan] Fixes the code generation for branches on x64 when the condition is
Word64Equal.

Before:

REX.W cmpq r9,r8
setzl r8l
movzxbl r8,r8
REX.W cmpq r8,0x0
jz 185

After:

REX.W cmpq r9,r8
jnz 149
==========

[commit-bot: I haz the power, 2016-02-05 15:00:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-02-05 15:01:19]

Description was changed from

==========
[turbofan] Fixes the code generation for branches on x64 when the condition is
Word64Equal.

Before:

REX.W cmpq r9,r8
setzl r8l
movzxbl r8,r8
REX.W cmpq r8,0x0
jz 185

After:

REX.W cmpq r9,r8
jnz 149
==========

to

==========
[turbofan] Fixes the code generation for branches on x64 when the condition is
Word64Equal.

Before:

REX.W cmpq r9,r8
setzl r8l
movzxbl r8,r8
REX.W cmpq r8,0x0
jz 185

After:

REX.W cmpq r9,r8
jnz 149

Committed: https://crrev.com/75cc8352d06aada2e9131fdae793299ef73fb639
Cr-Commit-Position: refs/heads/master@{#33784}
==========

[commit-bot: I haz the power, 2016-02-05 15:01:19]

Patchset 1 (id:??) landed as
https://crrev.com/75cc8352d06aada2e9131fdae793299ef73fb639
Cr-Commit-Position: refs/heads/master@{#33784}

[epertoso, 2016-02-11 09:22:42]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1693433002/ by epertoso@chromium.org.

The reason for reverting is: Code like the example given in the CL description
was produced, for example, by code-stub-assembler.cc.

Reverting this, and try to fix the root cause instead..