Use weak cell to embed known map in CompareIC

src/arm/code-stubs-arm.cc

 // Copyright 2012 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_ARM
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 3643 matching lines @@
   __ sub(r0, r0, Operand(r1));
   __ Ret();
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
 void CompareICStub::GenerateKnownObjects(MacroAssembler* masm) {
   Label miss;
+  Handle<WeakCell> cell = Map::WeakCellForMap(known_map_);
   __ and_(r2, r1, Operand(r0));
   __ JumpIfSmi(r2, &miss);
+  __ GetWeakValue(r4, cell);
   __ ldr(r2, FieldMemOperand(r0, HeapObject::kMapOffset));
   __ ldr(r3, FieldMemOperand(r1, HeapObject::kMapOffset));
-  __ cmp(r2, Operand(known_map_));
+  __ cmp(r2, r4);
   __ b(ne, &miss);
-  __ cmp(r3, Operand(known_map_));
+  __ cmp(r3, r4);
   __ b(ne, &miss);
 
   __ sub(r0, r0, Operand(r1));
   __ Ret();
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
@@ skipping 1262 matching lines @@
                            kStackUnwindSpace, NULL,
                            MemOperand(fp, 6 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM