Always require exact maps.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 58659241a66e1afd72f2a322347276dce878e546..0ee12e1e81056513464890f6f6dafda6a5973e50 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -2838,38 +2838,21 @@ void MacroAssembler::StoreNumberToDoubleElements(
 
 void MacroAssembler::CompareMap(Register obj,
                                 Handle<Map> map,
-                                Label* early_success,
-                                CompareMapMode mode) {
+                                Label* early_success) {
   Cmp(FieldOperand(obj, HeapObject::kMapOffset), map);
-  if (mode == ALLOW_ELEMENT_TRANSITION_MAPS) {
-    ElementsKind kind = map->elements_kind();
-    if (IsFastElementsKind(kind)) {
-      bool packed = IsFastPackedElementsKind(kind);
-      Map* current_map = *map;
-      while (CanTransitionToMoreGeneralFastElementsKind(kind, packed)) {
-        kind = GetNextMoreGeneralFastElementsKind(kind, packed);
-        current_map = current_map->LookupElementsTransitionMap(kind);
-        if (!current_map) break;
-        j(equal, early_success, Label::kNear);
-        Cmp(FieldOperand(obj, HeapObject::kMapOffset),
-            Handle<Map>(current_map));
-      }
-    }
-  }
 }
 
 
 void MacroAssembler::CheckMap(Register obj,
                               Handle<Map> map,
                               Label* fail,
-                              SmiCheckType smi_check_type,
-                              CompareMapMode mode) {
+                              SmiCheckType smi_check_type) {
   if (smi_check_type == DO_SMI_CHECK) {
     JumpIfSmi(obj, fail);
   }
 
   Label success;
-  CompareMap(obj, map, &success, mode);
+  CompareMap(obj, map, &success);
   j(not_equal, fail);
   bind(&success);
 }