Mercurial > hg > truffle
annotate src/share/vm/opto/loopUnswitch.cpp @ 2445:08eb13460b3a
7004535: Clone loop predicate during loop unswitch
Summary: Clone loop predicate for clonned loops
Reviewed-by: never
| author | kvn |
|---|---|
| date | Sat, 02 Apr 2011 10:54:15 -0700 |
| parents | 9dc311b8473e |
| children | 6c97c830fb6f |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 1972 | 2 * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 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 * | |
|
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
605
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
605
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
605
diff
changeset
|
21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "memory/allocation.inline.hpp" | |
| 27 #include "opto/connode.hpp" | |
| 28 #include "opto/loopnode.hpp" | |
| 29 #include "opto/rootnode.hpp" | |
| 0 | 30 |
| 31 //================= Loop Unswitching ===================== | |
| 32 // | |
| 33 // orig: transformed: | |
| 34 // if (invariant-test) then | |
| 2445 | 35 // predicate predicate |
| 0 | 36 // loop loop |
| 37 // stmt1 stmt1 | |
| 38 // if (invariant-test) then stmt2 | |
| 39 // stmt2 stmt4 | |
| 40 // else endloop | |
| 41 // stmt3 else | |
| 2445 | 42 // endif predicate [clone] |
| 43 // stmt4 loop [clone] | |
| 44 // endloop stmt1 [clone] | |
| 45 // stmt3 | |
| 0 | 46 // stmt4 [clone] |
| 47 // endloop | |
| 48 // endif | |
| 49 // | |
| 50 // Note: the "else" clause may be empty | |
| 51 | |
| 52 //------------------------------policy_unswitching----------------------------- | |
| 53 // Return TRUE or FALSE if the loop should be unswitched | |
| 54 // (ie. clone loop with an invariant test that does not exit the loop) | |
| 55 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const { | |
| 56 if( !LoopUnswitching ) { | |
| 57 return false; | |
| 58 } | |
| 108 | 59 if (!_head->is_Loop()) { |
| 60 return false; | |
| 61 } | |
| 0 | 62 uint nodes_left = MaxNodeLimit - phase->C->unique(); |
| 63 if (2 * _body.size() > nodes_left) { | |
| 64 return false; // Too speculative if running low on nodes. | |
| 65 } | |
| 66 LoopNode* head = _head->as_Loop(); | |
| 67 if (head->unswitch_count() + 1 > head->unswitch_max()) { | |
| 68 return false; | |
| 69 } | |
| 70 return phase->find_unswitching_candidate(this) != NULL; | |
| 71 } | |
| 72 | |
| 73 //------------------------------find_unswitching_candidate----------------------------- | |
| 74 // Find candidate "if" for unswitching | |
| 75 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const { | |
| 76 | |
| 77 // Find first invariant test that doesn't exit the loop | |
| 78 LoopNode *head = loop->_head->as_Loop(); | |
| 79 IfNode* unswitch_iff = NULL; | |
| 80 Node* n = head->in(LoopNode::LoopBackControl); | |
| 81 while (n != head) { | |
| 82 Node* n_dom = idom(n); | |
| 83 if (n->is_Region()) { | |
| 84 if (n_dom->is_If()) { | |
| 85 IfNode* iff = n_dom->as_If(); | |
| 86 if (iff->in(1)->is_Bool()) { | |
| 87 BoolNode* bol = iff->in(1)->as_Bool(); | |
| 88 if (bol->in(1)->is_Cmp()) { | |
| 89 // If condition is invariant and not a loop exit, | |
| 90 // then found reason to unswitch. | |
| 91 if (loop->is_invariant(bol) && !loop->is_loop_exit(iff)) { | |
| 92 unswitch_iff = iff; | |
| 93 } | |
| 94 } | |
| 95 } | |
| 96 } | |
| 97 } | |
| 98 n = n_dom; | |
| 99 } | |
| 100 return unswitch_iff; | |
| 101 } | |
| 102 | |
| 103 //------------------------------do_unswitching----------------------------- | |
| 104 // Clone loop with an invariant test (that does not exit) and | |
| 105 // insert a clone of the test that selects which version to | |
| 106 // execute. | |
| 107 void PhaseIdealLoop::do_unswitching (IdealLoopTree *loop, Node_List &old_new) { | |
| 108 | |
| 109 // Find first invariant test that doesn't exit the loop | |
| 110 LoopNode *head = loop->_head->as_Loop(); | |
| 111 | |
| 112 IfNode* unswitch_iff = find_unswitching_candidate((const IdealLoopTree *)loop); | |
| 113 assert(unswitch_iff != NULL, "should be at least one"); | |
| 114 | |
|
2383
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
115 #ifndef PRODUCT |
|
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
116 if (TraceLoopOpts) { |
|
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
117 tty->print("Unswitch %d ", head->unswitch_count()+1); |
|
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
118 loop->dump_head(); |
|
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
119 } |
|
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
120 #endif |
|
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
121 |
| 0 | 122 // Need to revert back to normal loop |
| 123 if (head->is_CountedLoop() && !head->as_CountedLoop()->is_normal_loop()) { | |
| 124 head->as_CountedLoop()->set_normal_loop(); | |
| 125 } | |
| 126 | |
| 127 ProjNode* proj_true = create_slow_version_of_loop(loop, old_new); | |
| 128 | |
| 2445 | 129 #ifdef ASSERT |
| 130 Node* uniqc = proj_true->unique_ctrl_out(); | |
| 131 Node* entry = head->in(LoopNode::EntryControl); | |
| 132 Node* predicate = find_predicate(entry); | |
| 133 if (predicate != NULL) predicate = predicate->in(0); | |
| 134 assert(proj_true->is_IfTrue() && | |
| 135 (predicate == NULL && uniqc == head || | |
| 136 predicate != NULL && uniqc == predicate), "by construction"); | |
| 137 #endif | |
| 0 | 138 // Increment unswitch count |
| 139 LoopNode* head_clone = old_new[head->_idx]->as_Loop(); | |
| 140 int nct = head->unswitch_count() + 1; | |
| 141 head->set_unswitch_count(nct); | |
| 142 head_clone->set_unswitch_count(nct); | |
| 143 | |
| 144 // Add test to new "if" outside of loop | |
| 145 IfNode* invar_iff = proj_true->in(0)->as_If(); | |
| 146 Node* invar_iff_c = invar_iff->in(0); | |
| 147 BoolNode* bol = unswitch_iff->in(1)->as_Bool(); | |
| 148 invar_iff->set_req(1, bol); | |
| 149 invar_iff->_prob = unswitch_iff->_prob; | |
| 150 | |
| 151 ProjNode* proj_false = invar_iff->proj_out(0)->as_Proj(); | |
| 152 | |
| 605 | 153 // Hoist invariant casts out of each loop to the appropriate |
| 0 | 154 // control projection. |
| 155 | |
| 156 Node_List worklist; | |
| 157 | |
| 158 for (DUIterator_Fast imax, i = unswitch_iff->fast_outs(imax); i < imax; i++) { | |
| 159 ProjNode* proj= unswitch_iff->fast_out(i)->as_Proj(); | |
| 160 // Copy to a worklist for easier manipulation | |
| 161 for (DUIterator_Fast jmax, j = proj->fast_outs(jmax); j < jmax; j++) { | |
| 162 Node* use = proj->fast_out(j); | |
| 163 if (use->Opcode() == Op_CheckCastPP && loop->is_invariant(use->in(1))) { | |
| 164 worklist.push(use); | |
| 165 } | |
| 166 } | |
| 167 ProjNode* invar_proj = invar_iff->proj_out(proj->_con)->as_Proj(); | |
| 168 while (worklist.size() > 0) { | |
| 169 Node* use = worklist.pop(); | |
| 170 Node* nuse = use->clone(); | |
| 171 nuse->set_req(0, invar_proj); | |
| 172 _igvn.hash_delete(use); | |
| 173 use->set_req(1, nuse); | |
| 174 _igvn._worklist.push(use); | |
| 175 register_new_node(nuse, invar_proj); | |
| 176 // Same for the clone | |
| 177 Node* use_clone = old_new[use->_idx]; | |
| 178 _igvn.hash_delete(use_clone); | |
| 179 use_clone->set_req(1, nuse); | |
| 180 _igvn._worklist.push(use_clone); | |
| 181 } | |
| 182 } | |
| 183 | |
| 184 // Hardwire the control paths in the loops into if(true) and if(false) | |
| 185 _igvn.hash_delete(unswitch_iff); | |
| 186 short_circuit_if(unswitch_iff, proj_true); | |
| 187 _igvn._worklist.push(unswitch_iff); | |
| 188 | |
| 189 IfNode* unswitch_iff_clone = old_new[unswitch_iff->_idx]->as_If(); | |
| 190 _igvn.hash_delete(unswitch_iff_clone); | |
| 191 short_circuit_if(unswitch_iff_clone, proj_false); | |
| 192 _igvn._worklist.push(unswitch_iff_clone); | |
| 193 | |
| 194 // Reoptimize loops | |
| 195 loop->record_for_igvn(); | |
| 196 for(int i = loop->_body.size() - 1; i >= 0 ; i--) { | |
| 197 Node *n = loop->_body[i]; | |
| 198 Node *n_clone = old_new[n->_idx]; | |
| 199 _igvn._worklist.push(n_clone); | |
| 200 } | |
| 201 | |
| 202 #ifndef PRODUCT | |
| 203 if (TraceLoopUnswitching) { | |
| 204 tty->print_cr("Loop unswitching orig: %d @ %d new: %d @ %d", | |
| 205 head->_idx, unswitch_iff->_idx, | |
| 206 old_new[head->_idx]->_idx, unswitch_iff_clone->_idx); | |
| 207 } | |
| 208 #endif | |
| 209 | |
| 210 C->set_major_progress(); | |
| 211 } | |
| 212 | |
| 213 //-------------------------create_slow_version_of_loop------------------------ | |
| 214 // Create a slow version of the loop by cloning the loop | |
| 215 // and inserting an if to select fast-slow versions. | |
| 216 // Return control projection of the entry to the fast version. | |
| 217 ProjNode* PhaseIdealLoop::create_slow_version_of_loop(IdealLoopTree *loop, | |
| 218 Node_List &old_new) { | |
| 219 LoopNode* head = loop->_head->as_Loop(); | |
| 220 Node* entry = head->in(LoopNode::EntryControl); | |
| 221 _igvn.hash_delete(entry); | |
| 222 _igvn._worklist.push(entry); | |
| 223 IdealLoopTree* outer_loop = loop->_parent; | |
| 224 | |
| 225 Node *cont = _igvn.intcon(1); | |
| 226 set_ctrl(cont, C->root()); | |
|
216
8d191a7697e2
6715633: when matching a memory node the adr_type should not change
kvn
parents:
108
diff
changeset
|
227 Node* opq = new (C, 2) Opaque1Node(C, cont); |
| 0 | 228 register_node(opq, outer_loop, entry, dom_depth(entry)); |
| 229 Node *bol = new (C, 2) Conv2BNode(opq); | |
| 230 register_node(bol, outer_loop, entry, dom_depth(entry)); | |
| 231 IfNode* iff = new (C, 2) IfNode(entry, bol, PROB_MAX, COUNT_UNKNOWN); | |
| 232 register_node(iff, outer_loop, entry, dom_depth(entry)); | |
| 233 ProjNode* iffast = new (C, 1) IfTrueNode(iff); | |
| 234 register_node(iffast, outer_loop, iff, dom_depth(iff)); | |
| 235 ProjNode* ifslow = new (C, 1) IfFalseNode(iff); | |
| 236 register_node(ifslow, outer_loop, iff, dom_depth(iff)); | |
| 237 | |
| 238 // Clone the loop body. The clone becomes the fast loop. The | |
| 2445 | 239 // original pre-header will (illegally) have 3 control users |
| 240 // (old & new loops & new if). | |
| 0 | 241 clone_loop(loop, old_new, dom_depth(head), iff); |
| 242 assert(old_new[head->_idx]->is_Loop(), "" ); | |
| 243 | |
| 244 // Fast (true) control | |
| 2445 | 245 Node* iffast_pred = clone_loop_predicates(entry, iffast); |
| 0 | 246 _igvn.hash_delete(head); |
| 2445 | 247 head->set_req(LoopNode::EntryControl, iffast_pred); |
| 248 set_idom(head, iffast_pred, dom_depth(head)); | |
| 0 | 249 _igvn._worklist.push(head); |
| 250 | |
| 251 // Slow (false) control | |
| 2445 | 252 Node* ifslow_pred = move_loop_predicates(entry, ifslow); |
| 0 | 253 LoopNode* slow_head = old_new[head->_idx]->as_Loop(); |
| 254 _igvn.hash_delete(slow_head); | |
| 2445 | 255 slow_head->set_req(LoopNode::EntryControl, ifslow_pred); |
| 256 set_idom(slow_head, ifslow_pred, dom_depth(slow_head)); | |
| 0 | 257 _igvn._worklist.push(slow_head); |
| 258 | |
| 259 recompute_dom_depth(); | |
| 260 | |
| 261 return iffast; | |
| 262 } |