Using array index hash code for string-to-number conversion.

src/arm/codegen-arm.cc

Index: src/arm/codegen-arm.cc
===================================================================
--- src/arm/codegen-arm.cc	(revision 5357)
+++ src/arm/codegen-arm.cc	(working copy)
@@ -5636,7 +5636,28 @@
 }
 
 
+void CodeGenerator::GenerateHasCachedArrayIndex(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 1);
+  Load(args->at(0));
+  Register value = frame_->PopToRegister();
+  Register tmp = frame_->scratch0();
+  __ ldr(tmp, FieldMemOperand(value, String::kHashFieldOffset));
+  __ tst(tmp, Operand(String::kContainsCachedArrayIndexMask));
+  cc_reg_ = eq;
+}
 
+
+void CodeGenerator::GenerateGetCachedArrayIndex(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 1);
+  Load(args->at(0));
+  Register value = frame_->PopToRegister();
+
+  __ ldr(value, FieldMemOperand(value, String::kHashFieldOffset));
+  __ IndexFromHash(value, value);
+  frame_->EmitPush(value);
+}
+
+
 void CodeGenerator::VisitCallRuntime(CallRuntime* node) {
 #ifdef DEBUG
   int original_height = frame_->height();