Add Arm64 support to dtoa/utils.h

Source/wtf/dtoa/utils.h

 // Copyright 2010 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 27 matching lines @@
 // Linux uses a 80bit wide floating point stack on x86. This induces double
 // rounding, which in turn leads to wrong results.
 // An easy way to test if the floating-point operations are correct is to
 // evaluate: 89255.0/1e22. If the floating-point stack is 64 bits wide then
 // the result is equal to 89255e-22.
 // The best way to test this, is to create a division-function and to compare
 // the output of the division with the expected result. (Inlining must be
 // disabled.)
 // On Linux,x86 89255e-22 != Div_double(89255.0/1e22)
 #if defined(_M_X64) || defined(__x86_64__) || \
-defined(__ARMEL__) || \
+defined(__ARMEL__) || defined(__aarch64__) || \
 defined(__MIPSEL__)
 #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
 #elif defined(_M_IX86) || defined(__i386__)
 #if defined(_WIN32)
 // Windows uses a 64bit wide floating point stack.
 #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
 #else
 #undef DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS
 #endif  // _WIN32
 #else
@@ skipping 239 matching lines @@
     template <class Dest, class Source>
     inline Dest BitCast(Source* source) {
         return BitCast<Dest>(reinterpret_cast<uintptr_t>(source));
     }
 
 }  // namespace double_conversion
 
 } // namespace WTF
 
 #endif  // DOUBLE_CONVERSION_UTILS_H_