Eliminate Smi check when changing from Smi to Integer32

Eliminate Smi check when changing from Smi to Integer32

BUG=
R=verwaest@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16362

[weiliang.lin2, 2013-08-12 14:35:39]

It seems
instr->type().IsSmi() != instr->representation.IsSmi()

[Toon Verwaest, 2013-08-12 14:53:42]

Added comments.

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc
File src/ia32/lithium-ia32.cc (right):

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc#newc...
src/ia32/lithium-ia32.cc:1907: if (to.IsSmiOrTagged()) {
Smi -> Smi doesn't happen, so this is superfluous.

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc#newc...
src/ia32/lithium-ia32.cc:1928: LNumberUntagD* res = new(zone())
LNumberUntagD(value, temp);
We should probably check the value representation in NumberUntagD as well?

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc#newc...
src/ia32/lithium-ia32.cc:1939: if (instr->value()->type().IsSmi()) {
What about val->type().IsSmi() || val->representation().IsSmi() instead of
duplicating code above?

[weiliang.lin2, 2013-08-13 02:36:57]

Addressed comments. Thanks for review~

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc
File src/ia32/lithium-ia32.cc (right):

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc#newc...
src/ia32/lithium-ia32.cc:1907: if (to.IsSmiOrTagged()) {
On 2013/08/12 14:53:42, Toon Verwaest wrote:
> Smi -> Smi doesn't happen, so this is superfluous.

Done.

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc#newc...
src/ia32/lithium-ia32.cc:1928: LNumberUntagD* res = new(zone())
LNumberUntagD(value, temp);
On 2013/08/12 14:53:42, Toon Verwaest wrote:
> We should probably check the value representation in NumberUntagD as well?

Done.

I found that NumberUntagD has already check the value representation. Could you
please have a double check?

https://codereview.chromium.org/22824003/diff/1/src/ia32/lithium-ia32.cc#newc...
src/ia32/lithium-ia32.cc:1939: if (instr->value()->type().IsSmi()) {
On 2013/08/12 14:53:42, Toon Verwaest wrote:
> What about val->type().IsSmi() || val->representation().IsSmi() instead of
> duplicating code above?

Yes, that is another way to fix
Done.

[weiliang.lin2, 2013-08-27 00:59:23]

rebase to latest source code

[Toon Verwaest, 2013-08-27 13:56:56]

lgtm. Landing. Thanks for the rebase.