Mercurial > hg > graal-compiler
annotate src/share/vm/opto/loopUnswitch.cpp @ 1552:c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair
| author | trims |
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| date | Thu, 27 May 2010 19:08:38 -0700 |
| parents | 98cb887364d3 |
| children | f95d63e2154a |
| rev | line source |
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| 0 | 1 /* |
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2 * Copyright (c) 2006, 2008, 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_loopUnswitch.cpp.incl" | |
| 27 | |
| 28 //================= Loop Unswitching ===================== | |
| 29 // | |
| 30 // orig: transformed: | |
| 31 // if (invariant-test) then | |
| 32 // loop loop | |
| 33 // stmt1 stmt1 | |
| 34 // if (invariant-test) then stmt2 | |
| 35 // stmt2 stmt4 | |
| 36 // else endloop | |
| 37 // stmt3 else | |
| 38 // endif loop [clone] | |
| 39 // stmt4 stmt1 [clone] | |
| 40 // endloop stmt3 | |
| 41 // stmt4 [clone] | |
| 42 // endloop | |
| 43 // endif | |
| 44 // | |
| 45 // Note: the "else" clause may be empty | |
| 46 | |
| 47 //------------------------------policy_unswitching----------------------------- | |
| 48 // Return TRUE or FALSE if the loop should be unswitched | |
| 49 // (ie. clone loop with an invariant test that does not exit the loop) | |
| 50 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const { | |
| 51 if( !LoopUnswitching ) { | |
| 52 return false; | |
| 53 } | |
| 108 | 54 if (!_head->is_Loop()) { |
| 55 return false; | |
| 56 } | |
| 0 | 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) { | |
| 77 Node* n_dom = idom(n); | |
| 78 if (n->is_Region()) { | |
| 79 if (n_dom->is_If()) { | |
| 80 IfNode* iff = n_dom->as_If(); | |
| 81 if (iff->in(1)->is_Bool()) { | |
| 82 BoolNode* bol = iff->in(1)->as_Bool(); | |
| 83 if (bol->in(1)->is_Cmp()) { | |
| 84 // If condition is invariant and not a loop exit, | |
| 85 // then found reason to unswitch. | |
| 86 if (loop->is_invariant(bol) && !loop->is_loop_exit(iff)) { | |
| 87 unswitch_iff = iff; | |
| 88 } | |
| 89 } | |
| 90 } | |
| 91 } | |
| 92 } | |
| 93 n = n_dom; | |
| 94 } | |
| 95 return unswitch_iff; | |
| 96 } | |
| 97 | |
| 98 //------------------------------do_unswitching----------------------------- | |
| 99 // Clone loop with an invariant test (that does not exit) and | |
| 100 // insert a clone of the test that selects which version to | |
| 101 // execute. | |
| 102 void PhaseIdealLoop::do_unswitching (IdealLoopTree *loop, Node_List &old_new) { | |
| 103 | |
| 104 // Find first invariant test that doesn't exit the loop | |
| 105 LoopNode *head = loop->_head->as_Loop(); | |
| 106 | |
| 107 IfNode* unswitch_iff = find_unswitching_candidate((const IdealLoopTree *)loop); | |
| 108 assert(unswitch_iff != NULL, "should be at least one"); | |
| 109 | |
| 110 // Need to revert back to normal loop | |
| 111 if (head->is_CountedLoop() && !head->as_CountedLoop()->is_normal_loop()) { | |
| 112 head->as_CountedLoop()->set_normal_loop(); | |
| 113 } | |
| 114 | |
| 115 ProjNode* proj_true = create_slow_version_of_loop(loop, old_new); | |
| 116 | |
| 117 assert(proj_true->is_IfTrue() && proj_true->unique_ctrl_out() == head, "by construction"); | |
| 118 | |
| 119 // Increment unswitch count | |
| 120 LoopNode* head_clone = old_new[head->_idx]->as_Loop(); | |
| 121 int nct = head->unswitch_count() + 1; | |
| 122 head->set_unswitch_count(nct); | |
| 123 head_clone->set_unswitch_count(nct); | |
| 124 | |
| 125 // Add test to new "if" outside of loop | |
| 126 IfNode* invar_iff = proj_true->in(0)->as_If(); | |
| 127 Node* invar_iff_c = invar_iff->in(0); | |
| 128 BoolNode* bol = unswitch_iff->in(1)->as_Bool(); | |
| 129 invar_iff->set_req(1, bol); | |
| 130 invar_iff->_prob = unswitch_iff->_prob; | |
| 131 | |
| 132 ProjNode* proj_false = invar_iff->proj_out(0)->as_Proj(); | |
| 133 | |
| 605 | 134 // Hoist invariant casts out of each loop to the appropriate |
| 0 | 135 // control projection. |
| 136 | |
| 137 Node_List worklist; | |
| 138 | |
| 139 for (DUIterator_Fast imax, i = unswitch_iff->fast_outs(imax); i < imax; i++) { | |
| 140 ProjNode* proj= unswitch_iff->fast_out(i)->as_Proj(); | |
| 141 // Copy to a worklist for easier manipulation | |
| 142 for (DUIterator_Fast jmax, j = proj->fast_outs(jmax); j < jmax; j++) { | |
| 143 Node* use = proj->fast_out(j); | |
| 144 if (use->Opcode() == Op_CheckCastPP && loop->is_invariant(use->in(1))) { | |
| 145 worklist.push(use); | |
| 146 } | |
| 147 } | |
| 148 ProjNode* invar_proj = invar_iff->proj_out(proj->_con)->as_Proj(); | |
| 149 while (worklist.size() > 0) { | |
| 150 Node* use = worklist.pop(); | |
| 151 Node* nuse = use->clone(); | |
| 152 nuse->set_req(0, invar_proj); | |
| 153 _igvn.hash_delete(use); | |
| 154 use->set_req(1, nuse); | |
| 155 _igvn._worklist.push(use); | |
| 156 register_new_node(nuse, invar_proj); | |
| 157 // Same for the clone | |
| 158 Node* use_clone = old_new[use->_idx]; | |
| 159 _igvn.hash_delete(use_clone); | |
| 160 use_clone->set_req(1, nuse); | |
| 161 _igvn._worklist.push(use_clone); | |
| 162 } | |
| 163 } | |
| 164 | |
| 165 // Hardwire the control paths in the loops into if(true) and if(false) | |
| 166 _igvn.hash_delete(unswitch_iff); | |
| 167 short_circuit_if(unswitch_iff, proj_true); | |
| 168 _igvn._worklist.push(unswitch_iff); | |
| 169 | |
| 170 IfNode* unswitch_iff_clone = old_new[unswitch_iff->_idx]->as_If(); | |
| 171 _igvn.hash_delete(unswitch_iff_clone); | |
| 172 short_circuit_if(unswitch_iff_clone, proj_false); | |
| 173 _igvn._worklist.push(unswitch_iff_clone); | |
| 174 | |
| 175 // Reoptimize loops | |
| 176 loop->record_for_igvn(); | |
| 177 for(int i = loop->_body.size() - 1; i >= 0 ; i--) { | |
| 178 Node *n = loop->_body[i]; | |
| 179 Node *n_clone = old_new[n->_idx]; | |
| 180 _igvn._worklist.push(n_clone); | |
| 181 } | |
| 182 | |
| 183 #ifndef PRODUCT | |
| 184 if (TraceLoopUnswitching) { | |
| 185 tty->print_cr("Loop unswitching orig: %d @ %d new: %d @ %d", | |
| 186 head->_idx, unswitch_iff->_idx, | |
| 187 old_new[head->_idx]->_idx, unswitch_iff_clone->_idx); | |
| 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()); | |
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208 Node* opq = new (C, 2) Opaque1Node(C, cont); |
| 0 | 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); | |
| 229 | |
| 230 // Slow (false) control | |
| 231 LoopNode* slow_head = old_new[head->_idx]->as_Loop(); | |
| 232 _igvn.hash_delete(slow_head); | |
| 233 slow_head->set_req(LoopNode::EntryControl, ifslow); | |
| 234 set_idom(slow_head, ifslow, dom_depth(slow_head)); | |
| 235 _igvn._worklist.push(slow_head); | |
| 236 | |
| 237 recompute_dom_depth(); | |
| 238 | |
| 239 return iffast; | |
| 240 } |