Fixed register usage in 64-bit version of

KeyedLoadIC::GenerateExternalArray which was causing it to go to the
slow case all the time.

Review URL: http://codereview.chromium.org/458008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3399 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/ic-x64.cc

@@ -378,7 +378,7 @@ void KeyedLoadIC::GenerateExternalArray(MacroAssembler* masm,
   // ExternalArray.
   // rax: index (as a smi)
   // rcx: JSObject
-  __ movq(rcx, FieldOperand(rdx, JSObject::kElementsOffset));
+  __ movq(rcx, FieldOperand(rcx, JSObject::kElementsOffset));
   __ CompareRoot(FieldOperand(rcx, HeapObject::kMapOffset),
                  Heap::RootIndexForExternalArrayType(array_type));
   __ j(not_equal, &slow);