[ia32/x64] Smaller instruction to check NaN

src/ia32/full-codegen-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 3075 matching lines @@
 
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
   Label* fall_through = NULL;
   context()->PrepareTest(&materialize_true, &materialize_false,
                          &if_true, &if_false, &fall_through);
 
   Handle<Map> map = masm()->isolate()->factory()->heap_number_map();
   __ CheckMap(eax, map, if_false, DO_SMI_CHECK);
-  __ cmp(FieldOperand(eax, HeapNumber::kExponentOffset), Immediate(0x80000000));
-  __ j(not_equal, if_false);
+  __ cmp(FieldOperand(eax, HeapNumber::kExponentOffset), Immediate(0x1));
+  __ j(no_overflow, if_false);
   __ cmp(FieldOperand(eax, HeapNumber::kMantissaOffset), Immediate(0x00000000));
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
   Split(equal, if_true, if_false, fall_through);
 
   context()->Plug(if_true, if_false);
 }
 
 
 
 void FullCodeGenerator::EmitIsArray(CallRuntime* expr) {
@@ skipping 1789 matching lines @@
   ASSERT_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32