Eliminate redundant smi checks

src/ia32/macro-assembler-ia32.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 225 matching lines @@
   }
 }
 
 
 void MacroAssembler::RecordWriteForMap(
     Register object,
     Handle<Map> map,
     Register scratch1,
     Register scratch2,
     SaveFPRegsMode save_fp) {
-  // First, check if a write barrier is even needed. The tests below
-  // catch stores of Smis.
   Label done;
 
   Register address = scratch1;
   Register value = scratch2;
   if (emit_debug_code()) {
     Label ok;
     lea(address, FieldOperand(object, HeapObject::kMapOffset));
     test_b(address, (1 << kPointerSizeLog2) - 1);
     j(zero, &ok, Label::kNear);
     int3();
@@ skipping 16 matching lines @@
   // the from object's page's interesting flag is also set.  This optimization
   // relies on the fact that maps can never be in new space.
   ASSERT(!isolate()->heap()->InNewSpace(*map));
   CheckPageFlagForMap(map,
                       MemoryChunk::kPointersToHereAreInterestingMask,
                       zero,
                       &done,
                       Label::kNear);
 
   // Delay the initialization of |address| and |value| for the stub until it's
-  // known that the will be needed. Up until this point their value are not
+  // known that the will be needed. Up until this point their values are not
   // needed since they are embedded in the operands of instructions that need
   // them.
   lea(address, FieldOperand(object, HeapObject::kMapOffset));
   mov(value, Immediate(map));
   RecordWriteStub stub(object, value, address, OMIT_REMEMBERED_SET, save_fp);
   CallStub(&stub);
 
   bind(&done);
 
   // Clobber clobbered input registers when running with the debug-code flag
@@ skipping 2613 matching lines @@
   // Load the prototype from the map and loop if non-null.
   bind(&check_prototype);
   mov(ecx, FieldOperand(ebx, Map::kPrototypeOffset));
   cmp(ecx, isolate()->factory()->null_value());
   j(not_equal, &next);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32