Fix uint32-to-smi conversion in Lithium

Fix uint32-to-smi conversion in Lithium

BUG=chromium:309623
R=vegorov@google.com, yangguo@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=17441

[Jakob Kummerow, 2013-10-31 09:15:21]

PTAL.

[Yang, 2013-10-31 09:30:57]

lgtm with one comment.

https://codereview.chromium.org/54393002/diff/1/src/arm/lithium-codegen-arm.cc
File src/arm/lithium-codegen-arm.cc (left):

https://codereview.chromium.org/54393002/diff/1/src/arm/lithium-codegen-arm.c...
src/arm/lithium-codegen-arm.cc:4653: ASSERT(input->IsRegister());
why do you remove these asserts?

[Jakob Kummerow, 2013-10-31 09:35:51]

Thanks, landing.

https://codereview.chromium.org/54393002/diff/1/src/arm/lithium-codegen-arm.cc
File src/arm/lithium-codegen-arm.cc (left):

https://codereview.chromium.org/54393002/diff/1/src/arm/lithium-codegen-arm.c...
src/arm/lithium-codegen-arm.cc:4653: ASSERT(input->IsRegister());
On 2013/10/31 09:30:57, Yang wrote:
> why do you remove these asserts?

Because they're useless. The subsequent ToRegister() calls contain the same
check.

[Vyacheslav Egorov (Google), 2013-10-31 09:51:16]

DBC

Please add an assertion in the Uint32 analysis in IsSafeUint32Use(), in the
branch for HChange that target representation is one of those that lithium
supports.

This will save on debugging next time a new representation is introduced.

[Vyacheslav Egorov (Google), 2013-10-31 10:05:36]

thanks for doing this!

https://codereview.chromium.org/54393002/diff/100001/src/hydrogen-uint32-anal...
File src/hydrogen-uint32-analysis.cc (right):

https://codereview.chromium.org/54393002/diff/100001/src/hydrogen-uint32-anal...
src/hydrogen-uint32-analysis.cc:43: ASSERT(!use->IsChange() ||
I would make it 

else if (use->IsSimulate()) {
  // Deoptimization has special support.
  return true;
} else if (use->IsChange()) {
  // Conversion has special support. This assert (the rest of the comment)...
  ASSERT(...);
}

to not have somewhat confusing !use->IsChange()

[Vyacheslav Egorov (Google), 2013-10-31 10:15:43]

LGTM!

[Jakob Kummerow, 2013-10-31 10:19:04]

Committed patchset #4 manually as r17441.