Add functions for setting an environment and rebinding a use.

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/code_generator.h"
@@ skipping 218 matching lines @@
           // Do another round of CSE to take secondary effects into account:
           // e.g. when eliminating dependent loads (a.x[0] + a.x[0])
           // TODO(fschneider): Change to a one-pass optimization pass.
           DominatorBasedCSE::Optimize(flow_graph);
           DEBUG_ASSERT(flow_graph->VerifyUseLists());
         }
       }
       if (FLAG_loop_invariant_code_motion &&
           (parsed_function.function().deoptimization_counter() <
            (FLAG_deoptimization_counter_threshold - 1))) {
-        LICM::Optimize(flow_graph);
+        LICM licm(flow_graph);
+        licm.Optimize();
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
       }
 
       if (FLAG_range_analysis) {
         // We have to perform range analysis after LICM because it
         // optimistically moves CheckSmi through phis into loop preheaders
         // making some phis smi.
         optimizer.InferSmiRanges();
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
       }
@@ skipping 398 matching lines @@
       Object::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     isolate->set_long_jump_base(base);
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart