Fix Smi vs. HeapObject confusion in HConstants.

src/conversions.h

 // Copyright 2011 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_CONVERSIONS_H_
 #define V8_CONVERSIONS_H_
 
 #include <limits>
 
 #include "src/base/logging.h"
@@ skipping 135 matching lines @@
 char* DoubleToPrecisionCString(double value, int f);
 char* DoubleToRadixCString(double value, int radix);
 
 
 static inline bool IsMinusZero(double value) {
   static const DoubleRepresentation minus_zero(-0.0);
   return DoubleRepresentation(value) == minus_zero;
 }
 
 
+static inline bool IsSmiDouble(double value) {
+  return !IsMinusZero(value) && value >= Smi::kMinValue &&
+         value <= Smi::kMaxValue && value == FastI2D(FastD2I(value));
+}
+
+
 // Integer32 is an integer that can be represented as a signed 32-bit
 // integer. It has to be in the range [-2^31, 2^31 - 1].
 // We also have to check for negative 0 as it is not an Integer32.
 static inline bool IsInt32Double(double value) {
   return !IsMinusZero(value) &&
          value >= kMinInt &&
          value <= kMaxInt &&
          value == FastI2D(FastD2I(value));
 }
 
@@ skipping 58 matching lines @@
                            Object* number) {
   size_t result = 0;
   bool is_valid = TryNumberToSize(isolate, number, &result);
   CHECK(is_valid);
   return result;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONVERSIONS_H_