Don't CheckSmi when type is Smi.

R=mvstanton@chromium.org

Review URL: https://chromiumcodereview.appspot.com/14890007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14605 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -1129,8 +1129,10 @@ HInstruction* HGraphBuilder::BuildFastElementAccess(
     switch (elements_kind) {
       case FAST_SMI_ELEMENTS:
       case FAST_HOLEY_SMI_ELEMENTS:
-        // Smi-only arrays need a smi check.
-        AddInstruction(new(zone) HCheckSmi(val));
+        if (!val->type().IsSmi()) {
+          // Smi-only arrays need a smi check.
+          AddInstruction(new(zone) HCheckSmi(val));
+        }
         // Fall through.
       case FAST_ELEMENTS:
       case FAST_HOLEY_ELEMENTS:
@@ -6934,9 +6936,11 @@ void HOptimizedGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
     switch (boilerplate_elements_kind) {
       case FAST_SMI_ELEMENTS:
       case FAST_HOLEY_SMI_ELEMENTS:
-        // Smi-only arrays need a smi check.
-        AddInstruction(new(zone()) HCheckSmi(value));
-        // Fall through.
+        if (!value->type().IsSmi()) {
+          // Smi-only arrays need a smi check.
+          AddInstruction(new(zone()) HCheckSmi(value));
+          // Fall through.
+        }
       case FAST_ELEMENTS:
       case FAST_HOLEY_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS: