Similar fix to merging trunc-div/mod: only one merge for now.

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/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 357 matching lines @@
         args->Add(new Value(curr_instr->right()->definition()));
 
         // Replace with TruncDivMod.
         MergedMathInstr* div_mod = new MergedMathInstr(
             args,
             curr_instr->deopt_id(),
             MergedMathInstr::kTruncDivMod);
         curr_instr->ReplaceWith(div_mod, current_iterator());
         other_binop->ReplaceUsesWith(div_mod);
         other_binop->RemoveFromGraph();
+        // Only one merge possible. Because canonicalization happens later,
+        // more candidates are possible.
+        // TODO(srdjan): Allow merging of trunc-div/mod into truncDivMod.
+        break;
       }
     }
   }
 }
 
 
 void FlowGraphOptimizer::TryMergeMathUnary(
     GrowableArray<MathUnaryInstr*>* merge_candidates) {
   if (!FlowGraphCompiler::SupportsSinCos()) {
     return;
@@ skipping 7939 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *fields);
   }
 }
 
 
 }  // namespace dart