Make map check in NamedStoreHandlerCompiler::GenerateFieldTypeChecks weak.

src/ic/mips64/handler-compiler-mips64.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS64
 
 #include "src/ic/call-optimization.h"
 #include "src/ic/handler-compiler.h"
@@ skipping 353 matching lines @@
   __ LoadInstanceDescriptors(map_reg, scratch);
   __ ld(scratch,
         FieldMemOperand(scratch, DescriptorArray::GetValueOffset(descriptor)));
   __ Branch(miss_label, ne, value_reg, Operand(scratch));
 }
 
 
 void NamedStoreHandlerCompiler::GenerateFieldTypeChecks(HeapType* field_type,
                                                         Register value_reg,
                                                         Label* miss_label) {
+  Register map_reg = scratch1();
+  Register scratch = scratch2();
+  DCHECK(!value_reg.is(map_reg));
+  DCHECK(!value_reg.is(scratch));
   __ JumpIfSmi(value_reg, miss_label);
   HeapType::Iterator<Map> it = field_type->Classes();
   if (!it.Done()) {
-    __ ld(scratch1(), FieldMemOperand(value_reg, HeapObject::kMapOffset));
+    __ ld(map_reg, FieldMemOperand(value_reg, HeapObject::kMapOffset));
     Label do_store;
-    Handle<Map> current;
     while (true) {
-      // Do the CompareMap() directly within the Branch() functions.
-      current = it.Current();
+      // Compare map directly within the Branch() functions.
       it.Advance();
+      __ GetWeakValue(scratch, Map::WeakCellForMap(it.Current()));
       if (it.Done()) {
-        __ Branch(miss_label, ne, scratch1(), Operand(current));
+        __ Branch(miss_label, ne, map_reg, Operand(scratch));
         break;
       }
-      __ Branch(&do_store, eq, scratch1(), Operand(current));
+      __ Branch(&do_store, eq, map_reg, Operand(scratch));
     }
     __ bind(&do_store);
   }
 }
 
 
 Register PropertyHandlerCompiler::CheckPrototypes(
     Register object_reg, Register holder_reg, Register scratch1,
     Register scratch2, Handle<Name> name, Label* miss,
     PrototypeCheckType check) {
@@ skipping 326 matching lines @@
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS64