Use builtin fmod for double modulo operation.

runtime/vm/flow_graph_optimizer.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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 1352 matching lines @@
           d2i_instr = new DoubleToIntegerInstr(call->ArgumentAt(0)->value(),
                                                call);
         } else {
           // Optimistically assume result fits into Smi.
           d2i_instr = new DoubleToSmiInstr(call->ArgumentAt(0)->value(), call);
         }
         call->ReplaceWith(d2i_instr, current_iterator());
         RemovePushArguments(call);
         return true;
       }
+      case MethodRecognizer::kDoubleMod:
       case MethodRecognizer::kDoublePow:
         ReplaceWithMathCFunction(call, recognized_kind);
         return true;
       case MethodRecognizer::kDoubleTruncate:
       case MethodRecognizer::kDoubleRound:
       case MethodRecognizer::kDoubleFloor:
       case MethodRecognizer::kDoubleCeil:
         if (!CPUFeatures::double_truncate_round_supported()) {
           ReplaceWithMathCFunction(call, recognized_kind);
         } else {
@@ skipping 3213 matching lines @@
 
   if (FLAG_trace_constant_propagation) {
     OS::Print("\n==== After constant propagation ====\n");
     FlowGraphPrinter printer(*graph_);
     printer.PrintBlocks();
   }
 }
 
 
 }  // namespace dart