DoNumberTagD performance improvement

src/arm/macro-assembler-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3106 matching lines @@
                                              failure);
 }
 
 
 // Allocates a heap number or jumps to the need_gc label if the young space
 // is full and a scavenge is needed.
 void MacroAssembler::AllocateHeapNumber(Register result,
                                         Register scratch1,
                                         Register scratch2,
                                         Register heap_number_map,
-                                        Label* gc_required) {
+                                        Label* gc_required,
+                                        TaggingMode tagging_mode) {
   // Allocate an object in the heap for the heap number and tag it as a heap
   // object.
   AllocateInNewSpace(HeapNumber::kSize,
                      result,
                      scratch1,
                      scratch2,
                      gc_required,
-                     TAG_OBJECT);
+                     tagging_mode == TAG_RESULT ? TAG_OBJECT :
+                                                  NO_ALLOCATION_FLAGS);
 
   // Store heap number map in the allocated object.
   AssertRegisterIsRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
-  str(heap_number_map, FieldMemOperand(result, HeapObject::kMapOffset));
+  if (tagging_mode == TAG_RESULT) {
+    str(heap_number_map, FieldMemOperand(result, HeapObject::kMapOffset));
+  } else {
+    str(heap_number_map, MemOperand(result, HeapObject::kMapOffset));
+  }
 }
 
 
 void MacroAssembler::AllocateHeapNumberWithValue(Register result,
                                                  DwVfpRegister value,
                                                  Register scratch1,
                                                  Register scratch2,
                                                  Register heap_number_map,
                                                  Label* gc_required) {
   AllocateHeapNumber(result, scratch1, scratch2, heap_number_map, gc_required);
@@ skipping 704 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM