Ignore redundant parallel moves when checking if a block is empty.

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
@@ skipping 2548 matching lines @@
   UNREACHABLE();
   return NULL;
 }
 
 
 void ParameterInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   UNREACHABLE();
 }
 
 
+bool ParallelMoveInstr::IsRedundant() const {
+  for (intptr_t i = 0; i < moves_.length(); i++) {
+    if (!moves_[i]->IsRedundant()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+
 LocationSummary* ParallelMoveInstr::MakeLocationSummary(Isolate* isolate,
                                                         bool optimizing) const {
   return NULL;
 }
 
 
 void ParallelMoveInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   UNREACHABLE();
 }
 
@@ skipping 777 matching lines @@
     case Token::kTRUNCDIV: return 0;
     case Token::kMOD: return 1;
     default: UNIMPLEMENTED(); return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart