519 }
520
521 //------------------------------Invariance-----------------------------------
522 // Helper class for loop_predication_impl to compute invariance on the fly and
523 // clone invariants.
524 class Invariance : public StackObj {
525 VectorSet _visited, _invariant;
526 Node_Stack _stack;
527 VectorSet _clone_visited;
528 Node_List _old_new; // map of old to new (clone)
529 IdealLoopTree* _lpt;
530 PhaseIdealLoop* _phase;
531
532 // Helper function to set up the invariance for invariance computation
533 // If n is a known invariant, set up directly. Otherwise, look up the
534 // the possibility to push n onto the stack for further processing.
535 void visit(Node* use, Node* n) {
536 if (_lpt->is_invariant(n)) { // known invariant
537 _invariant.set(n->_idx);
538 } else if (!n->is_CFG()) {
539 Node *n_ctrl = _phase->ctrl_or_self(n);
540 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG
541 if (_phase->is_dominator(n_ctrl, u_ctrl)) {
542 _stack.push(n, n->in(0) == NULL ? 1 : 0);
543 }
544 }
545 }
546
547 // Compute invariance for "the_node" and (possibly) all its inputs recursively
548 // on the fly
549 void compute_invariance(Node* n) {
550 assert(_visited.test(n->_idx), "must be");
551 visit(n, n);
552 while (_stack.is_nonempty()) {
553 Node* n = _stack.node();
554 uint idx = _stack.index();
555 if (idx == n->req()) { // all inputs are processed
556 _stack.pop();
557 // n is invariant if it's inputs are all invariant
558 bool all_inputs_invariant = true;
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519 }
520
521 //------------------------------Invariance-----------------------------------
522 // Helper class for loop_predication_impl to compute invariance on the fly and
523 // clone invariants.
524 class Invariance : public StackObj {
525 VectorSet _visited, _invariant;
526 Node_Stack _stack;
527 VectorSet _clone_visited;
528 Node_List _old_new; // map of old to new (clone)
529 IdealLoopTree* _lpt;
530 PhaseIdealLoop* _phase;
531
532 // Helper function to set up the invariance for invariance computation
533 // If n is a known invariant, set up directly. Otherwise, look up the
534 // the possibility to push n onto the stack for further processing.
535 void visit(Node* use, Node* n) {
536 if (_lpt->is_invariant(n)) { // known invariant
537 _invariant.set(n->_idx);
538 } else if (!n->is_CFG()) {
539 if (n->Opcode() == Op_ShenandoahWriteBarrier) {
540 return;
541 }
542 Node *n_ctrl = _phase->ctrl_or_self(n);
543 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG
544 if (_phase->is_dominator(n_ctrl, u_ctrl)) {
545 _stack.push(n, n->in(0) == NULL ? 1 : 0);
546 }
547 }
548 }
549
550 // Compute invariance for "the_node" and (possibly) all its inputs recursively
551 // on the fly
552 void compute_invariance(Node* n) {
553 assert(_visited.test(n->_idx), "must be");
554 visit(n, n);
555 while (_stack.is_nonempty()) {
556 Node* n = _stack.node();
557 uint idx = _stack.index();
558 if (idx == n->req()) { // all inputs are processed
559 _stack.pop();
560 // n is invariant if it's inputs are all invariant
561 bool all_inputs_invariant = true;
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