Add negative lookups to polymorphic loads in Crankshaft.

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
===================================================================
--- src/arm/macro-assembler-arm.cc	(revision 11774)
+++ src/arm/macro-assembler-arm.cc	(working copy)
@@ -2000,7 +2000,15 @@
                                 Label* early_success,
                                 CompareMapMode mode) {
   ldr(scratch, FieldMemOperand(obj, HeapObject::kMapOffset));
-  cmp(scratch, Operand(map));
+  CompareMap(scratch, map, early_success, mode);
+}
+
+
+void MacroAssembler::CompareMap(Register obj_map,
+                                Handle<Map> map,
+                                Label* early_success,
+                                CompareMapMode mode) {
+  cmp(obj_map, Operand(map));
   if (mode == ALLOW_ELEMENT_TRANSITION_MAPS) {
     ElementsKind kind = map->elements_kind();
     if (IsFastElementsKind(kind)) {
@@ -2011,7 +2019,7 @@
         current_map = current_map->LookupElementsTransitionMap(kind);
         if (!current_map) break;
         b(eq, early_success);
-        cmp(scratch, Operand(Handle<Map>(current_map)));
+        cmp(obj_map, Operand(Handle<Map>(current_map)));
       }
     }
   }