Fix array index dehoisting.

BUG=141395
TEST=

Review URL: https://chromiumcodereview.appspot.com/10919214

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12484 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -3743,6 +3743,7 @@ void HGraph::EliminateRedundantBoundsChecks() {
 
 static void DehoistArrayIndex(ArrayInstructionInterface* array_operation) {
   HValue* index = array_operation->GetKey();
+  if (!index->representation().IsInteger32()) return;
 
   HConstant* constant;
   HValue* subexpression;