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

runtime/vm/code_generator.cc

 // Copyright (c) 2013, 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 "vm/code_generator.h"
 
 #include "vm/assembler_macros.h"
 #include "vm/ast.h"
 #include "vm/bigint_operations.h"
 #include "vm/code_patcher.h"
@@ skipping 1699 matching lines @@
   if (!(object->IsHeapObject() && value->IsHeapObject())) {
     return;
   }
   HeapTrace* heap_trace = Isolate::Current()->heap()->trace();
   heap_trace->TraceStoreIntoObject(RawObject::ToAddr(object),
                                    field_addr,
                                    RawObject::ToAddr(value));
 }
 END_LEAF_RUNTIME_ENTRY
 
+
+double DartModulo(double left, double right) {
+  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 < 0.0) {
+    if (right < 0) {
+      remainder -= right;
+    } else {
+      remainder += right;
+    }
+  }
+  return remainder;
+}
+
 }  // namespace dart