Lithium: avoid registers for constants when possible. (issue 14364010)

[mvst...@chromium.org]

Reviewers: Toon Verwaest,

Message:
Hi Toon, here is the change we discussed. As noted, it reverts a portion of
https://codereview.chromium.org/14075014/ where that CL reduced the
productive
use of LConstants more than necessary.

Description:
Lithium: avoid registers for constants when possible.

BUG=

Please review this at https://codereview.chromium.org/14364010/

SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge

Affected files:
M src/arm/lithium-arm.cc
M src/arm/lithium-codegen-arm.cc
M src/hydrogen-instructions.h
M src/hydrogen.cc
M src/ia32/lithium-codegen-ia32.cc
M src/ia32/lithium-ia32.cc
M src/x64/lithium-codegen-x64.cc
M src/x64/lithium-x64.cc

[verw...@chromium.org]

lgtm with last nit.


https://codereview.chromium.org/14364010/diff/7001/src/ia32/lithium-codegen-ia32.cc
File src/ia32/lithium-codegen-ia32.cc (right):

https://codereview.chromium.org/14364010/diff/7001/src/ia32/lithium-codegen-ia32.cc#newcode6033
src/ia32/lithium-codegen-ia32.cc:6033: __ mov(result, 0);
Use Smi::FromInt(0) here and on x64

https://codereview.chromium.org/14364010/

[mvst...@chromium.org]

Committed patchset #4 manually as r14460 (presubmit successful).

https://codereview.chromium.org/14364010/