Check for negative zero in floor when compiling with MSVC.

src/utils.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_UTILS_H_
 #define V8_UTILS_H_
 
 #include <limits.h>
 #include <stdlib.h>
 #include <string.h>
+#include <cmath>
 
 #include "include/v8.h"
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/base/macros.h"
 #include "src/base/platform/platform.h"
 #include "src/globals.h"
 #include "src/list.h"
 #include "src/vector.h"
 
@@ skipping 112 matching lines @@
 }
 
 
 // Returns the absolute value of its argument.
 template <typename T>
 T Abs(T a) {
   return a < 0 ? -a : a;
 }
 
 
+// Floor(-0.0) == 0.0
+inline double Floor(double x) {
+#ifdef _MSC_VER
+  if (x == 0) return x;  // Fix for issue 3477.
+#endif
+  return std::floor(x);
+}
+
+
 // TODO(svenpanne) Clean up the whole power-of-2 mess.
 inline int32_t WhichPowerOf2Abs(int32_t x) {
   return (x == kMinInt) ? 31 : WhichPowerOf2(Abs(x));
 }
 
 
 // Obtains the unsigned type corresponding to T
 // available in C++11 as std::make_unsigned
 template<typename T>
 struct make_unsigned {
@@ skipping 1368 matching lines @@
   }
 
   *index = result;
   return true;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_UTILS_H_