Disable elimination of unreachable code after HSoftDeopts

src/hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1249 matching lines @@
 void HGraph::MarkAsDeoptimizingRecursively(HBasicBlock* block) {
   for (int i = 0; i < block->dominated_blocks()->length(); ++i) {
     HBasicBlock* dominated = block->dominated_blocks()->at(i);
     if (block->IsDeoptimizing()) dominated->MarkAsDeoptimizing();
     MarkAsDeoptimizingRecursively(dominated);
   }
 }
 
 
 void HGraph::NullifyUnreachableInstructions() {
+  if (!FLAG_unreachable_code_elimination) return;
   int block_count = blocks_.length();
   for (int i = 0; i < block_count; ++i) {
     HBasicBlock* block = blocks_.at(i);
     bool nullify = false;
     const ZoneList<HBasicBlock*>* predecessors = block->predecessors();
     int predecessors_length = predecessors->length();
     bool all_predecessors_deoptimizing = (predecessors_length > 0);
     for (int j = 0; j < predecessors_length; ++j) {
       if (!predecessors->at(j)->IsDeoptimizing()) {
         all_predecessors_deoptimizing = false;
@@ skipping 9006 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal