Introduce "optimized_out" oddball marker for compilers.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/ast-graph-builder.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
@@ skipping 628 matching lines @@
 }
 
 
 void AstGraphBuilder::ClearNonLiveSlotsInFrameStates() {
   if (!FLAG_analyze_environment_liveness ||
       !info()->is_deoptimization_enabled()) {
     return;
   }
 
   NonLiveFrameStateSlotReplacer replacer(
-      &state_values_cache_, jsgraph()->UndefinedConstant(),
+      &state_values_cache_, jsgraph()->OptimizedOutConstant(),
       liveness_analyzer()->local_count(), local_zone());
   Variable* arguments = info()->scope()->arguments();
   if (arguments != nullptr && arguments->IsStackAllocated()) {
     replacer.MarkPermanentlyLive(arguments->index());
   }
   liveness_analyzer()->Run(&replacer);
   if (FLAG_trace_environment_liveness) {
     OFStream os(stdout);
     liveness_analyzer()->Print(os);
   }
@@ skipping 3712 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8