With >= 64 non-string instance types, I removed an optimization

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 2794 matching lines @@
   and_(scratch2, kFlatAsciiStringMask);
   lea(scratch1, Operand(scratch1, scratch2, times_8, 0));
   cmp(scratch1, kFlatAsciiStringTag | (kFlatAsciiStringTag << 3));
   j(not_equal, failure);
 }
 
 
 void MacroAssembler::JumpIfNotUniqueName(Operand operand,
                                          Label* not_unique_name,
                                          Label::Distance distance) {
-  STATIC_ASSERT(((SYMBOL_TYPE - 1) & kIsInternalizedMask) == kInternalizedTag);
-  cmp(operand, Immediate(kInternalizedTag));
-  j(less, not_unique_name, distance);
-  cmp(operand, Immediate(SYMBOL_TYPE));
-  j(greater, not_unique_name, distance);
+  STATIC_ASSERT(kInternalizedTag == 0 && kStringTag == 0);
+  Label succeed;
+  test(operand, Immediate(kIsNotStringMask | kIsNotInternalizedMask));
+  j(zero, &succeed);
+  cmpb(operand, static_cast<uint8_t>(SYMBOL_TYPE));
+  j(not_equal, not_unique_name, distance);
+
+  bind(&succeed);
 }
 
 
 void MacroAssembler::PrepareCallCFunction(int num_arguments, Register scratch) {
   int frame_alignment = OS::ActivationFrameAlignment();
   if (frame_alignment != 0) {
     // Make stack end at alignment and make room for num_arguments words
     // and the original value of esp.
     mov(scratch, esp);
     sub(esp, Immediate((num_arguments + 1) * kPointerSize));
@@ skipping 351 matching lines @@
   j(greater, &no_info_available);
   cmp(MemOperand(scratch_reg, -AllocationSiteInfo::kSize),
       Immediate(Handle<Map>(isolate()->heap()->allocation_site_info_map())));
   bind(&no_info_available);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32