Don't create dummy uses for control dependencies.

src/x64/lithium-x64.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 839 matching lines @@
 
 void LChunkBuilder::VisitInstruction(HInstruction* current) {
   HInstruction* old_current = current_instruction_;
   current_instruction_ = current;
 
   LInstruction* instr = NULL;
   if (current->CanReplaceWithDummyUses()) {
     if (current->OperandCount() == 0) {
       instr = DefineAsRegister(new(zone()) LDummy());
     } else {
+      ASSERT(!current->OperandAt(0)->IsControlInstruction());
       instr = DefineAsRegister(new(zone())
           LDummyUse(UseAny(current->OperandAt(0))));
     }
     for (int i = 1; i < current->OperandCount(); ++i) {
+      if (current->OperandAt(i)->IsControlInstruction()) continue;
       LInstruction* dummy =
           new(zone()) LDummyUse(UseAny(current->OperandAt(i)));
       dummy->set_hydrogen_value(current);
       chunk_->AddInstruction(dummy, current_block_);
     }
   } else {
     instr = current->CompileToLithium(this);
   }
 
   argument_count_ += current->argument_delta();
@@ skipping 1571 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64