Add complete ElementKind information directly to Map for objects with elements.

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 05a5fbfde67b92d9ed526005eeba7bb8f47d2403..4aba1d649615b7d01bc079f9b2c0d0cf41456013 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -279,6 +279,16 @@ void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
 }
 
 
+void MacroAssembler::CheckFastElements(Register map,
+                                       Label* fail,
+                                       Label::Distance distance) {
+  STATIC_ASSERT(JSObject::FAST_ELEMENTS == 0);
+  cmpb(FieldOperand(map, Map::kBitField2Offset),
+       Map::kMaximumBitField2FastElementValue);
+  j(above, fail, distance);
+}
+
+
 void MacroAssembler::CheckMap(Register obj,
                               Handle<Map> map,
                               Label* fail,