[turbofan] Don't treat the hole NaN as constant inside the compiler.

src/assembler.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 102 matching lines @@
 namespace internal {
 
 // -----------------------------------------------------------------------------
 // Common double constants.
 
 struct DoubleConstant BASE_EMBEDDED {
 double min_int;
 double one_half;
 double minus_one_half;
 double negative_infinity;
-double the_hole_nan;
+uint64_t the_hole_nan;
 double uint32_bias;
 };
 
 static DoubleConstant double_constants;
 
 static struct V8_ALIGNED(16) {
   uint32_t a;
   uint32_t b;
   uint32_t c;
   uint32_t d;
@@ skipping 787 matching lines @@
   }
   UNREACHABLE();
   return ExternalReference::BUILTIN_CALL;
 }
 
 
 void ExternalReference::SetUp() {
   double_constants.min_int = kMinInt;
   double_constants.one_half = 0.5;
   double_constants.minus_one_half = -0.5;
-  double_constants.the_hole_nan = bit_cast<double>(kHoleNanInt64);
+  double_constants.the_hole_nan = kHoleNanInt64;
   double_constants.negative_infinity = -V8_INFINITY;
   double_constants.uint32_bias =
     static_cast<double>(static_cast<uint32_t>(0xFFFFFFFF)) + 1;
 }
 
 ExternalReference::ExternalReference(Address address, Isolate* isolate)
     : address_(Redirect(isolate, address)) {}
 
 ExternalReference::ExternalReference(
     ApiFunction* fun,
@@ skipping 1014 matching lines @@
 
 
 void Assembler::DataAlign(int m) {
   DCHECK(m >= 2 && base::bits::IsPowerOfTwo32(m));
   while ((pc_offset() & (m - 1)) != 0) {
     db(0);
   }
 }
 }  // namespace internal
 }  // namespace v8