//-------------------------create_slow_version_of_loop------------------------
// Create a slow version of the loop by cloning the loop
// and inserting an if to select fast-slow versions.
// Return control projection of the entry to the fast version.
ProjNode* PhaseIdealLoop::create_slow_version_of_loop(IdealLoopTree *loop,
Node_List &old_new,
int opcode) {
LoopNode* head = loop->_head->as_Loop();
bool counted_loop = head->is_CountedLoop();
Node* entry = head->in(LoopNode::EntryControl);
_igvn.rehash_node_delayed(entry);
IdealLoopTree* outer_loop = loop->_parent;
Node *cont = _igvn.intcon(1);
set_ctrl(cont, C->root());
Node* opq = new Opaque1Node(C, cont);
register_node(opq, outer_loop, entry, dom_depth(entry));
Node *bol = new Conv2BNode(opq);
register_node(bol, outer_loop, entry, dom_depth(entry));
IfNode* iff = (opcode == Op_RangeCheck) ? new RangeCheckNode(entry, bol, PROB_MAX, COUNT_UNKNOWN) :
new IfNode(entry, bol, PROB_MAX, COUNT_UNKNOWN);
register_node(iff, outer_loop, entry, dom_depth(entry));
ProjNode* iffast = new IfTrueNode(iff);
register_node(iffast, outer_loop, iff, dom_depth(iff));
ProjNode* ifslow = new IfFalseNode(iff);
register_node(ifslow, outer_loop, iff, dom_depth(iff));
// Clone the loop body. The clone becomes the fast loop. The
// original pre-header will (illegally) have 3 control users
// (old & new loops & new if).
clone_loop(loop, old_new, dom_depth(head), iff);
assert(old_new[head->_idx]->is_Loop(), "" );
// Fast (true) control
Node* iffast_pred = clone_loop_predicates(entry, iffast, !counted_loop);
_igvn.replace_input_of(head, LoopNode::EntryControl, iffast_pred);
set_idom(head, iffast_pred, dom_depth(head));
// Slow (false) control
Node* ifslow_pred = clone_loop_predicates(entry, ifslow, !counted_loop);
LoopNode* slow_head = old_new[head->_idx]->as_Loop();
_igvn.replace_input_of(slow_head, LoopNode::EntryControl, ifslow_pred);
set_idom(slow_head, ifslow_pred, dom_depth(slow_head));
recompute_dom_depth();
return iffast;
}
// Interface from PhaseIdealLoop
Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) {
return clone_loop_predicates(old_entry, new_entry, clone_limit_check, this, &this->_igvn);
}
