src/share/vm/c1/c1_Optimizer.cpp

rev 4136 : 7153771: array bound check elimination for c1
Summary: when possible optimize out array bound checks, inserting predicates when needed.
Reviewed-by:

*** 176,186 ****
    for_each_phi_fun(f_block, phi, return; );
  
    // 2) substitute conditional expression
    //    with an IfOp followed by a Goto
    // cut if_ away and get node before
!   Instruction* cur_end = if_->prev(block);
  
    // append constants of true- and false-block if necessary
    // clone constants because original block must not be destroyed
    assert((t_value != f_const && f_value != t_const) || t_const == f_const, "mismatch");
    if (t_value == t_const) {
--- 176,186 ----
    for_each_phi_fun(f_block, phi, return; );
  
    // 2) substitute conditional expression
    //    with an IfOp followed by a Goto
    // cut if_ away and get node before
!   Instruction* cur_end = if_->prev();
  
    // append constants of true- and false-block if necessary
    // clone constants because original block must not be destroyed
    assert((t_value != f_const && f_value != t_const) || t_const == f_const, "mismatch");
    if (t_value == t_const) {
*** 200,210 ****
      NOT_PRODUCT(result->set_printable_bci(if_->printable_bci()));
      cur_end = cur_end->set_next(result);
    }
  
    // append Goto to successor
!   ValueStack* state_before = if_->is_safepoint() ? if_->state_before() : NULL;
    Goto* goto_ = new Goto(sux, state_before, if_->is_safepoint() || t_goto->is_safepoint() || f_goto->is_safepoint());
  
    // prepare state for Goto
    ValueStack* goto_state = if_state;
    goto_state = goto_state->copy(ValueStack::StateAfter, goto_state->bci());
--- 200,210 ----
      NOT_PRODUCT(result->set_printable_bci(if_->printable_bci()));
      cur_end = cur_end->set_next(result);
    }
  
    // append Goto to successor
!   ValueStack* state_before = if_->state_before();
    Goto* goto_ = new Goto(sux, state_before, if_->is_safepoint() || t_goto->is_safepoint() || f_goto->is_safepoint());
  
    // prepare state for Goto
    ValueStack* goto_state = if_state;
    goto_state = goto_state->copy(ValueStack::StateAfter, goto_state->bci());
*** 365,378 ****
          }
          assert(sux_state->caller_state() == end_state->caller_state(), "caller not equal");
  #endif
  
          // find instruction before end & append first instruction of sux block
!         Instruction* prev = end->prev(block);
          Instruction* next = sux->next();
          assert(prev->as_BlockEnd() == NULL, "must not be a BlockEnd");
          prev->set_next(next);
          sux->disconnect_from_graph();
          block->set_end(sux->end());
          // add exception handlers of deleted block, if any
          for (int k = 0; k < sux->number_of_exception_handlers(); k++) {
            BlockBegin* xhandler = sux->exception_handler_at(k);
--- 365,379 ----
          }
          assert(sux_state->caller_state() == end_state->caller_state(), "caller not equal");
  #endif
  
          // find instruction before end & append first instruction of sux block
!         Instruction* prev = end->prev();
          Instruction* next = sux->next();
          assert(prev->as_BlockEnd() == NULL, "must not be a BlockEnd");
          prev->set_next(next);
+         prev->fixup_block_pointers();
          sux->disconnect_from_graph();
          block->set_end(sux->end());
          // add exception handlers of deleted block, if any
          for (int k = 0; k < sux->number_of_exception_handlers(); k++) {
            BlockBegin* xhandler = sux->exception_handler_at(k);
*** 531,540 ****
--- 532,543 ----
    void do_UnsafePrefetchWrite(UnsafePrefetchWrite* x);
    void do_ProfileCall    (ProfileCall*     x);
    void do_ProfileInvoke  (ProfileInvoke*   x);
    void do_RuntimeCall    (RuntimeCall*     x);
    void do_MemBar         (MemBar*          x);
+   void do_RangeCheckPredicate(RangeCheckPredicate* x);
+   void do_Assert         (Assert*          x);
  };
  
  
  // Because of a static contained within (for the purpose of iteration
  // over instructions), it is only valid to have one of these active at
*** 712,721 ****
--- 715,726 ----
  void NullCheckVisitor::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {}
  void NullCheckVisitor::do_ProfileCall    (ProfileCall*     x) { nce()->clear_last_explicit_null_check(); }
  void NullCheckVisitor::do_ProfileInvoke  (ProfileInvoke*   x) {}
  void NullCheckVisitor::do_RuntimeCall    (RuntimeCall*     x) {}
  void NullCheckVisitor::do_MemBar         (MemBar*          x) {}
+ void NullCheckVisitor::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
+ void NullCheckVisitor::do_Assert         (Assert*          x) {}
  
  
  void NullCheckEliminator::visit(Value* p) {
    assert(*p != NULL, "should not find NULL instructions");
    if (visitable(*p)) {