7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/connode.hpp"
28 #include "opto/convertnode.hpp"
29 #include "opto/loopnode.hpp"
30 #include "opto/opaquenode.hpp"
31 #include "opto/rootnode.hpp"
32
33 //================= Loop Unswitching =====================
34 //
35 // orig: transformed:
36 // if (invariant-test) then
37 // predicate predicate
38 // loop loop
39 // stmt1 stmt1
40 // if (invariant-test) then stmt2
41 // stmt2 stmt4
42 // else endloop
43 // stmt3 else
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 // If nodes are depleted, some transform has miscalculated its needs.
66 assert(!phase->exceeding_node_budget(), "sanity");
67
68 // check for vectorized loops, any unswitching was already applied
69 if (_head->is_CountedLoop() && _head->as_CountedLoop()->is_unroll_only()) {
70 return false;
71 }
72
73 LoopNode* head = _head->as_Loop();
74 if (head->unswitch_count() + 1 > head->unswitch_max()) {
75 return false;
76 }
77 if (phase->find_unswitching_candidate(this) == NULL) {
78 return false;
79 }
80
81 // Too speculative if running low on nodes.
82 return phase->may_require_nodes(est_loop_clone_sz(2));
83 }
84
85 //------------------------------find_unswitching_candidate-----------------------------
86 // Find candidate "if" for unswitching
87 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {
88
89 // Find first invariant test that doesn't exit the loop
90 LoopNode *head = loop->_head->as_Loop();
91 IfNode* unswitch_iff = NULL;
92 Node* n = head->in(LoopNode::LoopBackControl);
93 while (n != head) {
94 Node* n_dom = idom(n);
95 if (n->is_Region()) {
96 if (n_dom->is_If()) {
97 IfNode* iff = n_dom->as_If();
98 if (iff->in(1)->is_Bool()) {
99 BoolNode* bol = iff->in(1)->as_Bool();
100 if (bol->in(1)->is_Cmp()) {
101 // If condition is invariant and not a loop exit,
102 // then found reason to unswitch.
103 if (loop->is_invariant(bol) && !loop->is_loop_exit(iff)) {
104 unswitch_iff = iff;
105 }
106 }
107 }
108 }
109 }
110 n = n_dom;
111 }
112 return unswitch_iff;
113 }
114
115 //------------------------------do_unswitching-----------------------------
116 // Clone loop with an invariant test (that does not exit) and
117 // insert a clone of the test that selects which version to
118 // execute.
119 void PhaseIdealLoop::do_unswitching(IdealLoopTree *loop, Node_List &old_new) {
120
121 LoopNode *head = loop->_head->as_Loop();
122 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
123 if (find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check) != NULL
124 || (UseProfiledLoopPredicate && find_predicate_insertion_point(entry, Deoptimization::Reason_profile_predicate) != NULL)
125 || (UseLoopPredicate && find_predicate_insertion_point(entry, Deoptimization::Reason_predicate) != NULL)) {
126 assert(entry->is_IfProj(), "sanity - must be ifProj since there is at least one predicate");
127 if (entry->outcnt() > 1) {
128 // Bailout if there are loop predicates from which there are additional control dependencies (i.e. from
129 // loop entry 'entry') to previously partially peeled statements since this case is not handled and can lead
130 // to wrong execution. Remove this bailout, once this is fixed.
131 return;
132 }
133 }
134 // Find first invariant test that doesn't exit the loop
135 IfNode* unswitch_iff = find_unswitching_candidate((const IdealLoopTree *)loop);
136 assert(unswitch_iff != NULL, "should be at least one");
137
138 #ifndef PRODUCT
139 if (TraceLoopOpts) {
140 tty->print("Unswitch %d ", head->unswitch_count()+1);
141 loop->dump_head();
142 }
143 #endif
144
145 // Need to revert back to normal loop
146 if (head->is_CountedLoop() && !head->as_CountedLoop()->is_normal_loop()) {
147 head->as_CountedLoop()->set_normal_loop();
148 }
149
150 IfNode* invar_iff = create_slow_version_of_loop(loop, old_new, unswitch_iff, CloneIncludesStripMined);
151 ProjNode* proj_true = invar_iff->proj_out(1);
152 ProjNode* proj_false = invar_iff->proj_out(0);
153
154 #ifdef ASSERT
155 assert(proj_true->is_IfTrue(), "must be true projection");
156 entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
157 Node* predicate = find_predicate(entry);
158 if (predicate == NULL) {
159 // No empty predicate
160 Node* uniqc = proj_true->unique_ctrl_out();
161 assert((uniqc == head && !head->is_strip_mined()) || (uniqc == head->in(LoopNode::EntryControl)
162 && head->is_strip_mined()), "must hold by construction if no predicates");
163 } else {
164 // There is at least one empty predicate. When calling 'skip_loop_predicates' on each found empty predicate,
165 // we should end up at 'proj_true'.
166 Node* proj_before_first_empty_predicate = skip_loop_predicates(entry);
167 if (UseProfiledLoopPredicate) {
168 predicate = find_predicate(proj_before_first_empty_predicate);
169 if (predicate != NULL) {
170 proj_before_first_empty_predicate = skip_loop_predicates(predicate);
171 }
172 }
173 if (UseLoopPredicate) {
174 predicate = find_predicate(proj_before_first_empty_predicate);
175 if (predicate != NULL) {
176 proj_before_first_empty_predicate = skip_loop_predicates(predicate);
177 }
178 }
179 assert(proj_true == proj_before_first_empty_predicate, "must hold by construction if at least one predicate");
180 }
181 #endif
182 // Increment unswitch count
183 LoopNode* head_clone = old_new[head->_idx]->as_Loop();
184 int nct = head->unswitch_count() + 1;
185 head->set_unswitch_count(nct);
186 head_clone->set_unswitch_count(nct);
187
188 // Hoist invariant casts out of each loop to the appropriate
189 // control projection.
190
191 Node_List worklist;
192 for (DUIterator_Fast imax, i = unswitch_iff->fast_outs(imax); i < imax; i++) {
193 ProjNode* proj= unswitch_iff->fast_out(i)->as_Proj();
194 // Copy to a worklist for easier manipulation
195 for (DUIterator_Fast jmax, j = proj->fast_outs(jmax); j < jmax; j++) {
196 Node* use = proj->fast_out(j);
197 if (use->Opcode() == Op_CheckCastPP && loop->is_invariant(use->in(1))) {
198 worklist.push(use);
199 }
200 }
201 ProjNode* invar_proj = invar_iff->proj_out(proj->_con)->as_Proj();
202 while (worklist.size() > 0) {
203 Node* use = worklist.pop();
204 Node* nuse = use->clone();
205 nuse->set_req(0, invar_proj);
206 _igvn.replace_input_of(use, 1, nuse);
207 register_new_node(nuse, invar_proj);
208 // Same for the clone
209 Node* use_clone = old_new[use->_idx];
210 _igvn.replace_input_of(use_clone, 1, nuse);
211 }
212 }
213
214 // Hardwire the control paths in the loops into if(true) and if(false)
215 _igvn.rehash_node_delayed(unswitch_iff);
216 dominated_by(proj_true, unswitch_iff, false, false);
217
218 IfNode* unswitch_iff_clone = old_new[unswitch_iff->_idx]->as_If();
219 _igvn.rehash_node_delayed(unswitch_iff_clone);
220 dominated_by(proj_false, unswitch_iff_clone, false, false);
221
222 // Reoptimize loops
223 loop->record_for_igvn();
224 for(int i = loop->_body.size() - 1; i >= 0 ; i--) {
225 Node *n = loop->_body[i];
226 Node *n_clone = old_new[n->_idx];
227 _igvn._worklist.push(n_clone);
228 }
229
230 #ifndef PRODUCT
231 if (TraceLoopUnswitching) {
232 tty->print_cr("Loop unswitching orig: %d @ %d new: %d @ %d",
233 head->_idx, unswitch_iff->_idx,
234 old_new[head->_idx]->_idx, unswitch_iff_clone->_idx);
235 }
236 #endif
237
238 C->set_major_progress();
239 }
240
241 //-------------------------create_slow_version_of_loop------------------------
242 // Create a slow version of the loop by cloning the loop
243 // and inserting an if to select fast-slow versions.
244 // Return the inserted if.
245 IfNode* PhaseIdealLoop::create_slow_version_of_loop(IdealLoopTree *loop,
246 Node_List &old_new,
247 IfNode* unswitch_iff,
248 CloneLoopMode mode) {
249 LoopNode* head = loop->_head->as_Loop();
250 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
251 _igvn.rehash_node_delayed(entry);
252 IdealLoopTree* outer_loop = loop->_parent;
253
254 head->verify_strip_mined(1);
255
256 // Add test to new "if" outside of loop
257 Node *bol = unswitch_iff->in(1)->as_Bool();
258 IfNode* iff = (unswitch_iff->Opcode() == Op_RangeCheck) ? new RangeCheckNode(entry, bol, unswitch_iff->_prob, unswitch_iff->_fcnt) :
259 new IfNode(entry, bol, unswitch_iff->_prob, unswitch_iff->_fcnt);
260 register_node(iff, outer_loop, entry, dom_depth(entry));
261 ProjNode* iffast = new IfTrueNode(iff);
262 register_node(iffast, outer_loop, iff, dom_depth(iff));
263 ProjNode* ifslow = new IfFalseNode(iff);
264 register_node(ifslow, outer_loop, iff, dom_depth(iff));
265
266 // Clone the loop body. The clone becomes the slow loop. The
267 // original pre-header will (illegally) have 3 control users
268 // (old & new loops & new if).
269 clone_loop(loop, old_new, dom_depth(head->skip_strip_mined()), mode, iff);
270 assert(old_new[head->_idx]->is_Loop(), "" );
271
272 // Fast (true) and Slow (false) control
273 ProjNode* iffast_pred = iffast;
274 ProjNode* ifslow_pred = ifslow;
275 clone_predicates_to_unswitched_loop(loop, old_new, iffast_pred, ifslow_pred);
276
277 Node* l = head->skip_strip_mined();
278 _igvn.replace_input_of(l, LoopNode::EntryControl, iffast_pred);
279 set_idom(l, iffast_pred, dom_depth(l));
280 LoopNode* slow_l = old_new[head->_idx]->as_Loop()->skip_strip_mined();
281 _igvn.replace_input_of(slow_l, LoopNode::EntryControl, ifslow_pred);
282 set_idom(slow_l, ifslow_pred, dom_depth(l));
283
284 recompute_dom_depth();
285
286 return iff;
287 }
288
289 LoopNode* PhaseIdealLoop::create_reserve_version_of_loop(IdealLoopTree *loop, CountedLoopReserveKit* lk) {
290 Node_List old_new;
291 LoopNode* head = loop->_head->as_Loop();
292 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
293 _igvn.rehash_node_delayed(entry);
294 IdealLoopTree* outer_loop = head->is_strip_mined() ? loop->_parent->_parent : loop->_parent;
295
296 ConINode* const_1 = _igvn.intcon(1);
297 set_ctrl(const_1, C->root());
298 IfNode* iff = new IfNode(entry, const_1, PROB_MAX, COUNT_UNKNOWN);
299 register_node(iff, outer_loop, entry, dom_depth(entry));
300 ProjNode* iffast = new IfTrueNode(iff);
301 register_node(iffast, outer_loop, iff, dom_depth(iff));
302 ProjNode* ifslow = new IfFalseNode(iff);
303 register_node(ifslow, outer_loop, iff, dom_depth(iff));
304
305 // Clone the loop body. The clone becomes the slow loop. The
306 // original pre-header will (illegally) have 3 control users
307 // (old & new loops & new if).
308 clone_loop(loop, old_new, dom_depth(head), CloneIncludesStripMined, iff);
309 assert(old_new[head->_idx]->is_Loop(), "" );
310
311 LoopNode* slow_head = old_new[head->_idx]->as_Loop();
|
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/mulnode.hpp"
28 #include "opto/addnode.hpp"
29 #include "opto/connode.hpp"
30 #include "opto/convertnode.hpp"
31 #include "opto/loopnode.hpp"
32 #include "opto/opaquenode.hpp"
33 #include "opto/rootnode.hpp"
34
35 //================= Loop Unswitching =====================
36 //
37 // orig: transformed:
38 // if (invariant-test) then
39 // predicate predicate
40 // loop loop
41 // stmt1 stmt1
42 // if (invariant-test) then stmt2
43 // stmt2 stmt4
44 // else endloop
45 // stmt3 else
46 // endif predicate [clone]
47 // stmt4 loop [clone]
48 // endloop stmt1 [clone]
49 // stmt3
50 // stmt4 [clone]
51 // endloop
52 // endif
53 //
54 // Note: the "else" clause may be empty
55
56
57 //------------------------------policy_unswitching-----------------------------
58 // Return TRUE or FALSE if the loop should be unswitched
59 // (ie. clone loop with an invariant test that does not exit the loop)
60 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const {
61 if (!LoopUnswitching) {
62 return false;
63 }
64 if (!_head->is_Loop()) {
65 return false;
66 }
67
68 // If nodes are depleted, some transform has miscalculated its needs.
69 assert(!phase->exceeding_node_budget(), "sanity");
70
71 // check for vectorized loops, any unswitching was already applied
72 if (_head->is_CountedLoop() && _head->as_CountedLoop()->is_unroll_only()) {
73 return false;
74 }
75
76 LoopNode* head = _head->as_Loop();
77 if (head->unswitch_count() + 1 > head->unswitch_max()) {
78 return false;
79 }
80
81 if (head->is_flattened_arrays()) {
82 return false;
83 }
84
85 Node_List unswitch_iffs;
86 if (phase->find_unswitching_candidate(this, unswitch_iffs) == NULL) {
87 return false;
88 }
89
90 // Too speculative if running low on nodes.
91 return phase->may_require_nodes(est_loop_clone_sz(2));
92 }
93
94 //------------------------------find_unswitching_candidate-----------------------------
95 // Find candidate "if" for unswitching
96 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop, Node_List& unswitch_iffs) const {
97
98 // Find first invariant test that doesn't exit the loop
99 LoopNode *head = loop->_head->as_Loop();
100 IfNode* unswitch_iff = NULL;
101 Node* n = head->in(LoopNode::LoopBackControl);
102 while (n != head) {
103 Node* n_dom = idom(n);
104 if (n->is_Region()) {
105 if (n_dom->is_If()) {
106 IfNode* iff = n_dom->as_If();
107 if (iff->in(1)->is_Bool()) {
108 BoolNode* bol = iff->in(1)->as_Bool();
109 if (bol->in(1)->is_Cmp()) {
110 // If condition is invariant and not a loop exit,
111 // then found reason to unswitch.
112 if (loop->is_invariant(bol) && !loop->is_loop_exit(iff)) {
113 unswitch_iff = iff;
114 }
115 }
116 }
117 }
118 }
119 n = n_dom;
120 }
121 if (unswitch_iff != NULL) {
122 unswitch_iffs.push(unswitch_iff);
123 }
124
125 // Collect all non-flattened array checks for unswitching to create a fast loop
126 // without checks (only non-flattened array accesses) and a slow loop with checks.
127 if (unswitch_iff == NULL || unswitch_iff->is_flat_array_check(&_igvn)) {
128 for (uint i = 0; i < loop->_body.size(); i++) {
129 IfNode* n = loop->_body.at(i)->isa_If();
130 if (n != NULL && n != unswitch_iff && n->is_flat_array_check(&_igvn) &&
131 loop->is_invariant(n->in(1)) && !loop->is_loop_exit(n)) {
132 unswitch_iffs.push(n);
133 if (unswitch_iff == NULL) {
134 unswitch_iff = n;
135 }
136 }
137 }
138 }
139 return unswitch_iff;
140 }
141
142 //------------------------------do_unswitching-----------------------------
143 // Clone loop with an invariant test (that does not exit) and
144 // insert a clone of the test that selects which version to
145 // execute.
146 void PhaseIdealLoop::do_unswitching(IdealLoopTree *loop, Node_List &old_new) {
147
148 LoopNode *head = loop->_head->as_Loop();
149 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
150 if (find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check) != NULL
151 || (UseProfiledLoopPredicate && find_predicate_insertion_point(entry, Deoptimization::Reason_profile_predicate) != NULL)
152 || (UseLoopPredicate && find_predicate_insertion_point(entry, Deoptimization::Reason_predicate) != NULL)) {
153 assert(entry->is_IfProj(), "sanity - must be ifProj since there is at least one predicate");
154 if (entry->outcnt() > 1) {
155 // Bailout if there are loop predicates from which there are additional control dependencies (i.e. from
156 // loop entry 'entry') to previously partially peeled statements since this case is not handled and can lead
157 // to wrong execution. Remove this bailout, once this is fixed.
158 return;
159 }
160 }
161 // Find first invariant test that doesn't exit the loop
162 Node_List unswitch_iffs;
163 IfNode* unswitch_iff = find_unswitching_candidate((const IdealLoopTree *)loop, unswitch_iffs);
164 assert(unswitch_iff != NULL && unswitch_iff == unswitch_iffs.at(0), "should be at least one");
165 bool flat_array_checks = unswitch_iffs.size() > 1;
166
167 #ifndef PRODUCT
168 if (TraceLoopOpts) {
169 tty->print("Unswitch %d ", head->unswitch_count()+1);
170 loop->dump_head();
171 for (uint i = 0; i < unswitch_iffs.size(); i++) {
172 unswitch_iffs.at(i)->dump(3);
173 tty->cr();
174 }
175 }
176 #endif
177
178 // Need to revert back to normal loop
179 if (head->is_CountedLoop() && !head->as_CountedLoop()->is_normal_loop()) {
180 head->as_CountedLoop()->set_normal_loop();
181 }
182
183 IfNode* invar_iff = create_slow_version_of_loop(loop, old_new, unswitch_iffs, CloneIncludesStripMined);
184 ProjNode* proj_true = invar_iff->proj_out(1);
185 ProjNode* proj_false = invar_iff->proj_out(0);
186
187 #ifdef ASSERT
188 assert(proj_true->is_IfTrue(), "must be true projection");
189 entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
190 Node* predicate = find_predicate(entry);
191 if (predicate == NULL) {
192 // No empty predicate
193 Node* uniqc = proj_true->unique_ctrl_out();
194 assert((uniqc == head && !head->is_strip_mined()) || (uniqc == head->in(LoopNode::EntryControl)
195 && head->is_strip_mined()), "must hold by construction if no predicates");
196 } else {
197 // There is at least one empty predicate. When calling 'skip_loop_predicates' on each found empty predicate,
198 // we should end up at 'proj_true'.
199 Node* proj_before_first_empty_predicate = skip_loop_predicates(entry);
200 if (UseProfiledLoopPredicate) {
201 predicate = find_predicate(proj_before_first_empty_predicate);
202 if (predicate != NULL) {
203 proj_before_first_empty_predicate = skip_loop_predicates(predicate);
204 }
205 }
206 if (UseLoopPredicate) {
207 predicate = find_predicate(proj_before_first_empty_predicate);
208 if (predicate != NULL) {
209 proj_before_first_empty_predicate = skip_loop_predicates(predicate);
210 }
211 }
212 assert(proj_true == proj_before_first_empty_predicate, "must hold by construction if at least one predicate");
213 }
214 #endif
215 // Increment unswitch count
216 LoopNode* head_clone = old_new[head->_idx]->as_Loop();
217 int nct = head->unswitch_count() + 1;
218 head->set_unswitch_count(nct);
219 head_clone->set_unswitch_count(nct);
220
221 // Hoist invariant casts out of each loop to the appropriate control projection.
222 Node_List worklist;
223 for (uint i = 0; i < unswitch_iffs.size(); i++) {
224 IfNode* iff = unswitch_iffs.at(i)->as_If();
225 for (DUIterator_Fast imax, i = iff->fast_outs(imax); i < imax; i++) {
226 ProjNode* proj = iff->fast_out(i)->as_Proj();
227 // Copy to a worklist for easier manipulation
228 for (DUIterator_Fast jmax, j = proj->fast_outs(jmax); j < jmax; j++) {
229 Node* use = proj->fast_out(j);
230 if (use->Opcode() == Op_CheckCastPP && loop->is_invariant(use->in(1))) {
231 worklist.push(use);
232 }
233 }
234 ProjNode* invar_proj = invar_iff->proj_out(proj->_con)->as_Proj();
235 while (worklist.size() > 0) {
236 Node* use = worklist.pop();
237 Node* nuse = use->clone();
238 nuse->set_req(0, invar_proj);
239 _igvn.replace_input_of(use, 1, nuse);
240 register_new_node(nuse, invar_proj);
241 // Same for the clone if we are removing checks from the slow loop
242 if (!flat_array_checks) {
243 Node* use_clone = old_new[use->_idx];
244 _igvn.replace_input_of(use_clone, 1, nuse);
245 }
246 }
247 }
248 }
249
250 // Hardwire the control paths in the loops into if(true) and if(false)
251 for (uint i = 0; i < unswitch_iffs.size(); i++) {
252 IfNode* iff = unswitch_iffs.at(i)->as_If();
253 _igvn.rehash_node_delayed(iff);
254 dominated_by(proj_true, iff);
255 }
256 IfNode* unswitch_iff_clone = old_new[unswitch_iff->_idx]->as_If();
257 if (!flat_array_checks) {
258 ProjNode* proj_false = invar_iff->proj_out(0)->as_Proj();
259 _igvn.rehash_node_delayed(unswitch_iff_clone);
260 dominated_by(proj_false, unswitch_iff_clone);
261 } else {
262 // Leave the flattened array checks in the slow loop and
263 // prevent it from being unswitched again based on these checks.
264 head_clone->mark_flattened_arrays();
265 }
266
267 // Reoptimize loops
268 loop->record_for_igvn();
269 for(int i = loop->_body.size() - 1; i >= 0 ; i--) {
270 Node *n = loop->_body[i];
271 Node *n_clone = old_new[n->_idx];
272 _igvn._worklist.push(n_clone);
273 }
274
275 #ifndef PRODUCT
276 if (TraceLoopUnswitching) {
277 for (uint i = 0; i < unswitch_iffs.size(); i++) {
278 tty->print_cr("Loop unswitching orig: %d @ %d new: %d @ %d",
279 head->_idx, unswitch_iffs.at(i)->_idx,
280 old_new[head->_idx]->_idx, old_new[unswitch_iffs.at(i)->_idx]->_idx);
281 }
282 }
283 #endif
284
285 C->set_major_progress();
286 }
287
288 //-------------------------create_slow_version_of_loop------------------------
289 // Create a slow version of the loop by cloning the loop
290 // and inserting an if to select fast-slow versions.
291 // Return the inserted if.
292 IfNode* PhaseIdealLoop::create_slow_version_of_loop(IdealLoopTree *loop,
293 Node_List &old_new,
294 Node_List &unswitch_iffs,
295 CloneLoopMode mode) {
296 LoopNode* head = loop->_head->as_Loop();
297 bool counted_loop = head->is_CountedLoop();
298 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
299 _igvn.rehash_node_delayed(entry);
300 IdealLoopTree* outer_loop = loop->_parent;
301
302 head->verify_strip_mined(1);
303
304 // Add test to new "if" outside of loop
305 IfNode* unswitch_iff = unswitch_iffs.at(0)->as_If();
306 BoolNode* bol = unswitch_iff->in(1)->as_Bool();
307 if (unswitch_iffs.size() > 1) {
308 // Flattened array checks are used on array access to switch between
309 // a legacy object array access and a flattened inline type array
310 // access. We want the performance impact on legacy accesses to be
311 // as small as possible so we make two copies of the loop: a fast
312 // one where all accesses are known to be legacy, a slow one where
313 // some accesses are to flattened arrays. Flattened array checks
314 // can be removed from the fast loop (true proj) but not from the
315 // slow loop (false proj) as it can have a mix of flattened/legacy accesses.
316 assert(bol->_test._test == BoolTest::ne, "IfTrue proj must point to flat array");
317 bol = bol->clone()->as_Bool();
318 register_new_node(bol, entry);
319 FlatArrayCheckNode* cmp = bol->in(1)->clone()->as_FlatArrayCheck();
320 register_new_node(cmp, entry);
321 bol->set_req(1, cmp);
322 // Combine all checks into a single one that fails if one array is flattened
323 assert(cmp->req() == 3, "unexpected number of inputs for FlatArrayCheck");
324 cmp->add_req_batch(C->top(), unswitch_iffs.size() - 1);
325 for (uint i = 0; i < unswitch_iffs.size(); i++) {
326 Node* array = unswitch_iffs.at(i)->in(1)->in(1)->in(FlatArrayCheckNode::Array);
327 cmp->set_req(FlatArrayCheckNode::Array + i, array);
328 }
329 }
330
331 IfNode* iff = (unswitch_iff->Opcode() == Op_RangeCheck) ? new RangeCheckNode(entry, bol, unswitch_iff->_prob, unswitch_iff->_fcnt) :
332 new IfNode(entry, bol, unswitch_iff->_prob, unswitch_iff->_fcnt);
333 register_node(iff, outer_loop, entry, dom_depth(entry));
334 ProjNode* iffast = new IfTrueNode(iff);
335 register_node(iffast, outer_loop, iff, dom_depth(iff));
336 ProjNode* ifslow = new IfFalseNode(iff);
337 register_node(ifslow, outer_loop, iff, dom_depth(iff));
338
339 // Clone the loop body. The clone becomes the slow loop. The
340 // original pre-header will (illegally) have 3 control users
341 // (old & new loops & new if).
342 clone_loop(loop, old_new, dom_depth(head->skip_strip_mined()), mode, iff);
343 assert(old_new[head->_idx]->is_Loop(), "" );
344
345 // Fast (true) and Slow (false) control
346 ProjNode* iffast_pred = iffast;
347 ProjNode* ifslow_pred = ifslow;
348 clone_predicates_to_unswitched_loop(loop, old_new, iffast_pred, ifslow_pred);
349
350 Node* l = head->skip_strip_mined();
351 _igvn.replace_input_of(l, LoopNode::EntryControl, iffast_pred);
352 set_idom(l, iffast_pred, dom_depth(l));
353 LoopNode* slow_l = old_new[head->_idx]->as_Loop()->skip_strip_mined();
354 _igvn.replace_input_of(slow_l, LoopNode::EntryControl, ifslow_pred);
355 set_idom(slow_l, ifslow_pred, dom_depth(l));
356
357 recompute_dom_depth();
358
359 return iff;
360 }
361
362 LoopNode* PhaseIdealLoop::create_reserve_version_of_loop(IdealLoopTree *loop, CountedLoopReserveKit* lk) {
363 Node_List old_new;
364 LoopNode* head = loop->_head->as_Loop();
365 bool counted_loop = head->is_CountedLoop();
366 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
367 _igvn.rehash_node_delayed(entry);
368 IdealLoopTree* outer_loop = head->is_strip_mined() ? loop->_parent->_parent : loop->_parent;
369
370 ConINode* const_1 = _igvn.intcon(1);
371 set_ctrl(const_1, C->root());
372 IfNode* iff = new IfNode(entry, const_1, PROB_MAX, COUNT_UNKNOWN);
373 register_node(iff, outer_loop, entry, dom_depth(entry));
374 ProjNode* iffast = new IfTrueNode(iff);
375 register_node(iffast, outer_loop, iff, dom_depth(iff));
376 ProjNode* ifslow = new IfFalseNode(iff);
377 register_node(ifslow, outer_loop, iff, dom_depth(iff));
378
379 // Clone the loop body. The clone becomes the slow loop. The
380 // original pre-header will (illegally) have 3 control users
381 // (old & new loops & new if).
382 clone_loop(loop, old_new, dom_depth(head), CloneIncludesStripMined, iff);
383 assert(old_new[head->_idx]->is_Loop(), "" );
384
385 LoopNode* slow_head = old_new[head->_idx]->as_Loop();
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