1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)loopUnswitch.cpp 1.6 07/06/29 14:41:32 JVM"
3 #endif
4 /*
5 * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
37 // if (invariant-test) then stmt2
38 // stmt2 stmt4
39 // else endloop
40 // stmt3 else
41 // endif loop [clone]
42 // stmt4 stmt1 [clone]
43 // endloop stmt3
44 // stmt4 [clone]
45 // endloop
46 // endif
47 //
48 // Note: the "else" clause may be empty
49
50 //------------------------------policy_unswitching-----------------------------
51 // Return TRUE or FALSE if the loop should be unswitched
52 // (ie. clone loop with an invariant test that does not exit the loop)
53 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const {
54 if( !LoopUnswitching ) {
55 return false;
56 }
57 uint nodes_left = MaxNodeLimit - phase->C->unique();
58 if (2 * _body.size() > nodes_left) {
59 return false; // Too speculative if running low on nodes.
60 }
61 LoopNode* head = _head->as_Loop();
62 if (head->unswitch_count() + 1 > head->unswitch_max()) {
63 return false;
64 }
65 return phase->find_unswitching_candidate(this) != NULL;
66 }
67
68 //------------------------------find_unswitching_candidate-----------------------------
69 // Find candidate "if" for unswitching
70 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {
71
72 // Find first invariant test that doesn't exit the loop
73 LoopNode *head = loop->_head->as_Loop();
74 IfNode* unswitch_iff = NULL;
75 Node* n = head->in(LoopNode::LoopBackControl);
76 while (n != head) {
188 }
189 #endif
190
191 C->set_major_progress();
192 }
193
194 //-------------------------create_slow_version_of_loop------------------------
195 // Create a slow version of the loop by cloning the loop
196 // and inserting an if to select fast-slow versions.
197 // Return control projection of the entry to the fast version.
198 ProjNode* PhaseIdealLoop::create_slow_version_of_loop(IdealLoopTree *loop,
199 Node_List &old_new) {
200 LoopNode* head = loop->_head->as_Loop();
201 Node* entry = head->in(LoopNode::EntryControl);
202 _igvn.hash_delete(entry);
203 _igvn._worklist.push(entry);
204 IdealLoopTree* outer_loop = loop->_parent;
205
206 Node *cont = _igvn.intcon(1);
207 set_ctrl(cont, C->root());
208 Node* opq = new (C, 2) Opaque1Node(cont);
209 register_node(opq, outer_loop, entry, dom_depth(entry));
210 Node *bol = new (C, 2) Conv2BNode(opq);
211 register_node(bol, outer_loop, entry, dom_depth(entry));
212 IfNode* iff = new (C, 2) IfNode(entry, bol, PROB_MAX, COUNT_UNKNOWN);
213 register_node(iff, outer_loop, entry, dom_depth(entry));
214 ProjNode* iffast = new (C, 1) IfTrueNode(iff);
215 register_node(iffast, outer_loop, iff, dom_depth(iff));
216 ProjNode* ifslow = new (C, 1) IfFalseNode(iff);
217 register_node(ifslow, outer_loop, iff, dom_depth(iff));
218
219 // Clone the loop body. The clone becomes the fast loop. The
220 // original pre-header will (illegally) have 2 control users (old & new loops).
221 clone_loop(loop, old_new, dom_depth(head), iff);
222 assert(old_new[head->_idx]->is_Loop(), "" );
223
224 // Fast (true) control
225 _igvn.hash_delete(head);
226 head->set_req(LoopNode::EntryControl, iffast);
227 set_idom(head, iffast, dom_depth(head));
228 _igvn._worklist.push(head);
|
1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)loopUnswitch.cpp 1.6 07/06/29 14:41:32 JVM"
3 #endif
4 /*
5 * Copyright 2006-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
37 // if (invariant-test) then stmt2
38 // stmt2 stmt4
39 // else endloop
40 // stmt3 else
41 // endif loop [clone]
42 // stmt4 stmt1 [clone]
43 // endloop stmt3
44 // stmt4 [clone]
45 // endloop
46 // endif
47 //
48 // Note: the "else" clause may be empty
49
50 //------------------------------policy_unswitching-----------------------------
51 // Return TRUE or FALSE if the loop should be unswitched
52 // (ie. clone loop with an invariant test that does not exit the loop)
53 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const {
54 if( !LoopUnswitching ) {
55 return false;
56 }
57 if (!_head->is_Loop()) {
58 return false;
59 }
60 uint nodes_left = MaxNodeLimit - phase->C->unique();
61 if (2 * _body.size() > nodes_left) {
62 return false; // Too speculative if running low on nodes.
63 }
64 LoopNode* head = _head->as_Loop();
65 if (head->unswitch_count() + 1 > head->unswitch_max()) {
66 return false;
67 }
68 return phase->find_unswitching_candidate(this) != NULL;
69 }
70
71 //------------------------------find_unswitching_candidate-----------------------------
72 // Find candidate "if" for unswitching
73 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {
74
75 // Find first invariant test that doesn't exit the loop
76 LoopNode *head = loop->_head->as_Loop();
77 IfNode* unswitch_iff = NULL;
78 Node* n = head->in(LoopNode::LoopBackControl);
79 while (n != head) {
191 }
192 #endif
193
194 C->set_major_progress();
195 }
196
197 //-------------------------create_slow_version_of_loop------------------------
198 // Create a slow version of the loop by cloning the loop
199 // and inserting an if to select fast-slow versions.
200 // Return control projection of the entry to the fast version.
201 ProjNode* PhaseIdealLoop::create_slow_version_of_loop(IdealLoopTree *loop,
202 Node_List &old_new) {
203 LoopNode* head = loop->_head->as_Loop();
204 Node* entry = head->in(LoopNode::EntryControl);
205 _igvn.hash_delete(entry);
206 _igvn._worklist.push(entry);
207 IdealLoopTree* outer_loop = loop->_parent;
208
209 Node *cont = _igvn.intcon(1);
210 set_ctrl(cont, C->root());
211 Node* opq = new (C, 2) Opaque1Node(C, cont);
212 register_node(opq, outer_loop, entry, dom_depth(entry));
213 Node *bol = new (C, 2) Conv2BNode(opq);
214 register_node(bol, outer_loop, entry, dom_depth(entry));
215 IfNode* iff = new (C, 2) IfNode(entry, bol, PROB_MAX, COUNT_UNKNOWN);
216 register_node(iff, outer_loop, entry, dom_depth(entry));
217 ProjNode* iffast = new (C, 1) IfTrueNode(iff);
218 register_node(iffast, outer_loop, iff, dom_depth(iff));
219 ProjNode* ifslow = new (C, 1) IfFalseNode(iff);
220 register_node(ifslow, outer_loop, iff, dom_depth(iff));
221
222 // Clone the loop body. The clone becomes the fast loop. The
223 // original pre-header will (illegally) have 2 control users (old & new loops).
224 clone_loop(loop, old_new, dom_depth(head), iff);
225 assert(old_new[head->_idx]->is_Loop(), "" );
226
227 // Fast (true) control
228 _igvn.hash_delete(head);
229 head->set_req(LoopNode::EntryControl, iffast);
230 set_idom(head, iffast, dom_depth(head));
231 _igvn._worklist.push(head);
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