Don't insert HDummyUses for control instructions

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 1285 matching lines @@
           // Insert an HDummyUse for each operand, unless the operand
           // is an HDummyUse itself. If it's even from the same block,
           // remember it as a potential replacement for the instruction.
           if (operand->IsDummyUse()) {
             if (operand->block() == instr->block() &&
                 last_dummy == NULL) {
               last_dummy = HInstruction::cast(operand);
             }
             continue;
           }
+          if (operand->IsControlInstruction()) {
+            // Inserting a dummy use for a value that's not defined anywhere
+            // will fail. Some instructions define fake inputs on such
+            // values as control flow dependencies.
+            continue;
+          }
           HDummyUse* dummy = new(zone()) HDummyUse(operand);
           dummy->InsertBefore(instr);
           last_dummy = dummy;
         }
         if (last_dummy == NULL) last_dummy = GetConstant1();
         instr->DeleteAndReplaceWith(last_dummy);
         continue;
       }
       if (instr->IsSoftDeoptimize()) {
         ASSERT(block->IsDeoptimizing());
@@ skipping 8964 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal