Fixup redefinitions before doing code motion

runtime/vm/compiler.cc

 // Copyright (c) 2012, 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/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 924 matching lines @@
                 flow_graph->Canonicalize();
               }
               DEBUG_ASSERT(flow_graph->VerifyUseLists());
             }
           }
 
           // Run loop-invariant code motion right after load elimination since
           // it depends on the numbering of loads from the previous
           // load-elimination.
           if (FLAG_loop_invariant_code_motion) {
+            flow_graph->RenameUsesDominatedByRedefinitions();
+            DEBUG_ASSERT(flow_graph->VerifyRedefinitions());
             LICM licm(flow_graph);
             licm.Optimize();
             DEBUG_ASSERT(flow_graph->VerifyUseLists());
           }
           flow_graph->RemoveRedefinitions();
         }
 
         // Optimize (a << b) & c patterns, merge operations.
         // Run after CSE in order to have more opportunity to merge
         // instructions that have same inputs.
@@ skipping 1310 matching lines @@
 
 
 bool BackgroundCompiler::IsDisabled() {
   UNREACHABLE();
   return true;
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart