Rollback of r11118, r11109 in trunk branch.

src/hydrogen-instructions.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 581 matching lines @@
     ASSERT(next->IsSimulate());
     previous = next;
     next = previous->next_;
   }
 
   previous_ = previous;
   next_ = next;
   SetBlock(block);
   previous->next_ = this;
   if (next != NULL) next->previous_ = this;
-  if (block->last() == previous) {
-    block->set_last(this);
-  }
 }
 
 
 #ifdef DEBUG
 void HInstruction::Verify() {
   // Verify that input operands are defined before use.
   HBasicBlock* cur_block = block();
   for (int i = 0; i < OperandCount(); ++i) {
     HValue* other_operand = OperandAt(i);
     HBasicBlock* other_block = other_operand->block();
@@ skipping 1725 matching lines @@
 
 
 void HCheckPrototypeMaps::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal