Eliminate Smi check when changing from Smi to Integer32

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 5d84935aed54e54a3e7591ffa0ab2ca237a28495..821a80493691b93cd0b808cb3f15483b699174ad 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1904,10 +1904,14 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   Representation from = instr->from();
   Representation to = instr->to();
   if (from.IsSmi()) {
-    if (to.IsTagged()) {
+    if (to.IsSmiOrTagged()) {

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

Smi -> Smi doesn't happen, so this is superfluous.

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

Done.

       LOperand* value = UseRegister(instr->value());
       return DefineSameAsFirst(new(zone()) LDummyUse(value));
     }
+    if (to.IsInteger32()) {
+      LOperand* value = UseRegister(instr->value());
+      return DefineSameAsFirst(new(zone()) LSmiUntag(value, false));
+    }
     from = Representation::Tagged();
   }
   // Only mark conversions that might need to allocate as calling rather than