Revert r4782. Fix issues 728, 732.

src/utils.h

 // Copyright 2006-2008 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 19 matching lines @@
 
 #include <stdlib.h>
 #include <string.h>
 
 namespace v8 {
 namespace internal {
 
 // ----------------------------------------------------------------------------
 // General helper functions
 
+#define IS_POWER_OF_TWO(x) (((x) & ((x) - 1)) == 0)
+
 // Returns true iff x is a power of 2 (or zero). Cannot be used with the
 // maximally negative value of the type T (the -1 overflows).
 template <typename T>
 static inline bool IsPowerOf2(T x) {
-  return (x & (x - 1)) == 0;
+  return IS_POWER_OF_TWO(x);
 }
 
 
 // The C++ standard leaves the semantics of '>>' undefined for
 // negative signed operands. Most implementations do the right thing,
 // though.
 static inline int ArithmeticShiftRight(int x, int s) {
   return x >> s;
 }
 
@@ skipping 644 matching lines @@
 
   Dest dest;
   memcpy(&dest, &source, sizeof(dest));
   return dest;
 }
 
 } }  // namespace v8::internal
 
 
 #endif  // V8_UTILS_H_