44 // endif predicate [clone]
45 // stmt4 loop [clone]
46 // endloop stmt1 [clone]
47 // stmt3
48 // stmt4 [clone]
49 // endloop
50 // endif
51 //
52 // Note: the "else" clause may be empty
53
54 //------------------------------policy_unswitching-----------------------------
55 // Return TRUE or FALSE if the loop should be unswitched
56 // (ie. clone loop with an invariant test that does not exit the loop)
57 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const {
58 if( !LoopUnswitching ) {
59 return false;
60 }
61 if (!_head->is_Loop()) {
62 return false;
63 }
64 int nodes_left = phase->C->max_node_limit() - phase->C->live_nodes();
65 if ((int)(2 * _body.size()) > nodes_left) {
66 return false; // Too speculative if running low on nodes.
67 }
68 LoopNode* head = _head->as_Loop();
69 if (head->unswitch_count() + 1 > head->unswitch_max()) {
70 return false;
71 }
72 return phase->find_unswitching_candidate(this) != NULL;
73 }
74
75 //------------------------------find_unswitching_candidate-----------------------------
76 // Find candidate "if" for unswitching
77 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {
78
79 // Find first invariant test that doesn't exit the loop
80 LoopNode *head = loop->_head->as_Loop();
81 IfNode* unswitch_iff = NULL;
82 Node* n = head->in(LoopNode::LoopBackControl);
83 while (n != head) {
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44 // endif predicate [clone]
45 // stmt4 loop [clone]
46 // endloop stmt1 [clone]
47 // stmt3
48 // stmt4 [clone]
49 // endloop
50 // endif
51 //
52 // Note: the "else" clause may be empty
53
54 //------------------------------policy_unswitching-----------------------------
55 // Return TRUE or FALSE if the loop should be unswitched
56 // (ie. clone loop with an invariant test that does not exit the loop)
57 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const {
58 if( !LoopUnswitching ) {
59 return false;
60 }
61 if (!_head->is_Loop()) {
62 return false;
63 }
64
65 // check for vectorized loops, any unswitching was already applied
66 if (_head->is_CountedLoop() && _head->as_CountedLoop()->do_unroll_only()) {
67 return false;
68 }
69
70 int nodes_left = phase->C->max_node_limit() - phase->C->live_nodes();
71 if ((int)(2 * _body.size()) > nodes_left) {
72 return false; // Too speculative if running low on nodes.
73 }
74 LoopNode* head = _head->as_Loop();
75 if (head->unswitch_count() + 1 > head->unswitch_max()) {
76 return false;
77 }
78 return phase->find_unswitching_candidate(this) != NULL;
79 }
80
81 //------------------------------find_unswitching_candidate-----------------------------
82 // Find candidate "if" for unswitching
83 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {
84
85 // Find first invariant test that doesn't exit the loop
86 LoopNode *head = loop->_head->as_Loop();
87 IfNode* unswitch_iff = NULL;
88 Node* n = head->in(LoopNode::LoopBackControl);
89 while (n != head) {
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