Enable correct optimized double modulo operation. (TODO: enable remainder optimization).

runtime/lib/double.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <math.h>
 
 #include "vm/bootstrap_natives.h"
 
 #include "vm/bigint_operations.h"
+#include "vm/code_generator.h"  // DartModulo.
 #include "vm/double_conversion.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, trace_intrinsified_natives);
 
@@ skipping 76 matching lines @@
   }
   return DoubleToInteger(trunc(left / right),
                          "Result of truncating division is Infinity or NaN");
 }
 
 
 DEFINE_NATIVE_ENTRY(Double_modulo, 2) {
   double left = Double::CheckedHandle(arguments->NativeArgAt(0)).value();
   GET_NON_NULL_NATIVE_ARGUMENT(Double, right_object, arguments->NativeArgAt(1));
   double right = right_object.value();
-
-  double remainder = fmod_ieee(left, right);
-  if (remainder == 0.0) {
-    // We explicitely switch to the positive 0.0 (just in case it was negative).
-    remainder = +0.0;
-  } else if (remainder < 0) {
-    if (right < 0) {
-      remainder -= right;
-    } else {
-      remainder += right;
-    }
-  }
-  return Double::New(remainder);
+  return Double::New(DartModulo(left, right));
 }
 
 
 DEFINE_NATIVE_ENTRY(Double_remainder, 2) {
   double left = Double::CheckedHandle(arguments->NativeArgAt(0)).value();
   GET_NON_NULL_NATIVE_ARGUMENT(Double, right_object, arguments->NativeArgAt(1));
   double right = right_object.value();
   return Double::New(fmod_ieee(left, right));
 }
 
@@ skipping 204 matching lines @@
 
 DEFINE_NATIVE_ENTRY(Double_getIsNegative, 1) {
   const Double& arg = Double::CheckedHandle(arguments->NativeArgAt(0));
   // Include negative zero, infinity.
   return Bool::Get(signbit(arg.value()) && !isnan(arg.value()));
 }
 
 // Add here only functions using/referring to old-style casts.
 
 }  // namespace dart