[ia32/x64] Smaller instruction to check NaN

src/x64/code-stubs-x64.cc

 // Copyright 2013 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 691 matching lines @@
   if (exponent_type_ != INTEGER) {
     Label fast_power, try_arithmetic_simplification;
     // Detect integer exponents stored as double.
     __ DoubleToI(exponent, double_exponent, double_scratch,
                  TREAT_MINUS_ZERO_AS_ZERO, &try_arithmetic_simplification);
     __ jmp(&int_exponent);
 
     __ bind(&try_arithmetic_simplification);
     __ cvttsd2si(exponent, double_exponent);
     // Skip to runtime if possibly NaN (indicated by the indefinite integer).
-    __ cmpl(exponent, Immediate(0x80000000u));
-    __ j(equal, &call_runtime);
+    __ cmpl(exponent, Immediate(0x1));
+    __ j(overflow, &call_runtime);
 
     if (exponent_type_ == ON_STACK) {
       // Detect square root case.  Crankshaft detects constant +/-0.5 at
       // compile time and uses DoMathPowHalf instead.  We then skip this check
       // for non-constant cases of +/-0.5 as these hardly occur.
       Label continue_sqrt, continue_rsqrt, not_plus_half;
       // Test for 0.5.
       // Load double_scratch with 0.5.
       __ movq(scratch, V8_UINT64_C(0x3FE0000000000000));
       __ movq(double_scratch, scratch);
@@ skipping 4591 matching lines @@
                               return_value_operand,
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64