[turbofan] Implement jump threading after register allocation.

[turbofan] Implement jump threading after register allocation.

R=dcarney@chromium.org
BUG=

[dcarney, 2014-11-24 15:59:09]

lgtm

https://codereview.chromium.org/754843002/diff/1/src/compiler/jump-threading.cc
File src/compiler/jump-threading.cc (right):

https://codereview.chromium.org/754843002/diff/1/src/compiler/jump-threading....
src/compiler/jump-threading.cc:87: } else if (instr->arch_opcode() == kArchNop)
{
a bunch of stuff is encoded as nops - you want to continue if outputcount == 0
&& inputcount == 0 && tempcount == 0 (or create and use instructions for the
other cases)

https://codereview.chromium.org/754843002/diff/1/src/compiler/pipeline.cc
File src/compiler/pipeline.cc (right):

https://codereview.chromium.org/754843002/diff/1/src/compiler/pipeline.cc#new...
src/compiler/pipeline.cc:918: // Optimimize jumps.
if (FLAG_turbo_jt)

[titzer, 2014-11-24 18:13:43]

On 2014/11/24 15:59:09, dcarney wrote:
> lgtm
> 
>
https://codereview.chromium.org/754843002/diff/1/src/compiler/jump-threading.cc
> File src/compiler/jump-threading.cc (right):
> 
>
https://codereview.chromium.org/754843002/diff/1/src/compiler/jump-threading....
> src/compiler/jump-threading.cc:87: } else if (instr->arch_opcode() ==
kArchNop)
> {
> a bunch of stuff is encoded as nops - you want to continue if outputcount == 0
> && inputcount == 0 && tempcount == 0 (or create and use instructions for the
> other cases)

We should not abuse nops, but I added your suggests.

> 
> https://codereview.chromium.org/754843002/diff/1/src/compiler/pipeline.cc
> File src/compiler/pipeline.cc (right):
> 
>
https://codereview.chromium.org/754843002/diff/1/src/compiler/pipeline.cc#new...
> src/compiler/pipeline.cc:918: // Optimimize jumps.
> if (FLAG_turbo_jt)

Done.

[titzer, 2014-11-24 18:13:48]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2014-11-24 18:14:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/754843002/20001

[commit-bot: I haz the power, 2014-11-24 18:29:41]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-11-24 18:29:42]

Try jobs failed on following builders:
  v8_win64_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_win64_rel/builds/579)

[titzer, 2014-11-24 18:40:21]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2014-11-24 18:41:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/754843002/40001

[commit-bot: I haz the power, 2014-11-24 18:58:02]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-11-24 18:58:03]

Try jobs failed on following builders:
  v8_win64_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_win64_rel/builds/582)

[titzer, 2014-11-25 09:02:12]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2014-11-25 09:02:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/754843002/60001

[commit-bot: I haz the power, 2014-11-25 09:16:31]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-11-25 09:16:32]

Try jobs failed on following builders:
  v8_win64_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_win64_rel/builds/586)

[dcarney, 2014-11-25 20:32:36]

https://codereview.chromium.org/754843002/diff/80001/src/compiler/jump-thread...
File src/compiler/jump-threading.cc (right):

https://codereview.chromium.org/754843002/diff/80001/src/compiler/jump-thread...
src/compiler/jump-threading.cc:97: // can't skip other instructions.
you forgot to skip sourceposition instructions

[titzer, 2014-11-26 09:37:23]

https://codereview.chromium.org/754843002/diff/80001/src/compiler/jump-thread...
File src/compiler/jump-threading.cc (right):

https://codereview.chromium.org/754843002/diff/80001/src/compiler/jump-thread...
src/compiler/jump-threading.cc:97: // can't skip other instructions.
On 2014/11/25 20:32:36, dcarney wrote:
> you forgot to skip sourceposition instructions

Done.

https://codereview.chromium.org/754843002/diff/80001/src/compiler/jump-thread...
src/compiler/jump-threading.cc:183: }
Note that I update all the immediates in the instruction sequence now, so I
don't have to hunt through the operands of the instructions like a monkey.

[titzer, 2014-11-26 10:41:01]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2014-11-26 10:42:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/754843002/140001

[commit-bot: I haz the power, 2014-11-26 11:22:45]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-11-26 11:22:46]

Try jobs failed on following builders:
  v8_linux64_asan_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_asan_rel/builds/161)

[titzer, 2014-11-26 12:12:08]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2014-11-26 12:12:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/754843002/160001

[commit-bot: I haz the power, 2014-11-26 12:41:54]

Committed patchset #9 (id:160001)