Mercurial > hg > graal-jvmci-8
annotate src/share/vm/opto/loopTransform.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 | cb162b348743 |
| children | 8b2317d732ec |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2000, 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 * | |
|
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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 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "compiler/compileLog.hpp" | |
| 27 #include "memory/allocation.inline.hpp" | |
| 28 #include "opto/addnode.hpp" | |
| 29 #include "opto/callnode.hpp" | |
| 30 #include "opto/connode.hpp" | |
| 31 #include "opto/divnode.hpp" | |
| 32 #include "opto/loopnode.hpp" | |
| 33 #include "opto/mulnode.hpp" | |
| 34 #include "opto/rootnode.hpp" | |
| 35 #include "opto/runtime.hpp" | |
| 36 #include "opto/subnode.hpp" | |
| 0 | 37 |
| 38 //------------------------------is_loop_exit----------------------------------- | |
| 39 // Given an IfNode, return the loop-exiting projection or NULL if both | |
| 40 // arms remain in the loop. | |
| 41 Node *IdealLoopTree::is_loop_exit(Node *iff) const { | |
| 42 if( iff->outcnt() != 2 ) return NULL; // Ignore partially dead tests | |
| 43 PhaseIdealLoop *phase = _phase; | |
| 44 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
| 45 // we need loop unswitching instead of peeling. | |
| 46 if( !is_member(phase->get_loop( iff->raw_out(0) )) ) | |
| 47 return iff->raw_out(0); | |
| 48 if( !is_member(phase->get_loop( iff->raw_out(1) )) ) | |
| 49 return iff->raw_out(1); | |
| 50 return NULL; | |
| 51 } | |
| 52 | |
| 53 | |
| 54 //============================================================================= | |
| 55 | |
| 56 | |
| 57 //------------------------------record_for_igvn---------------------------- | |
| 58 // Put loop body on igvn work list | |
| 59 void IdealLoopTree::record_for_igvn() { | |
| 60 for( uint i = 0; i < _body.size(); i++ ) { | |
| 61 Node *n = _body.at(i); | |
| 62 _phase->_igvn._worklist.push(n); | |
| 63 } | |
| 64 } | |
| 65 | |
| 66 //------------------------------compute_profile_trip_cnt---------------------------- | |
| 67 // Compute loop trip count from profile data as | |
| 68 // (backedge_count + loop_exit_count) / loop_exit_count | |
| 69 void IdealLoopTree::compute_profile_trip_cnt( PhaseIdealLoop *phase ) { | |
| 70 if (!_head->is_CountedLoop()) { | |
| 71 return; | |
| 72 } | |
| 73 CountedLoopNode* head = _head->as_CountedLoop(); | |
| 74 if (head->profile_trip_cnt() != COUNT_UNKNOWN) { | |
| 75 return; // Already computed | |
| 76 } | |
| 77 float trip_cnt = (float)max_jint; // default is big | |
| 78 | |
| 79 Node* back = head->in(LoopNode::LoopBackControl); | |
| 80 while (back != head) { | |
| 81 if ((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && | |
| 82 back->in(0) && | |
| 83 back->in(0)->is_If() && | |
| 84 back->in(0)->as_If()->_fcnt != COUNT_UNKNOWN && | |
| 85 back->in(0)->as_If()->_prob != PROB_UNKNOWN) { | |
| 86 break; | |
| 87 } | |
| 88 back = phase->idom(back); | |
| 89 } | |
| 90 if (back != head) { | |
| 91 assert((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && | |
| 92 back->in(0), "if-projection exists"); | |
| 93 IfNode* back_if = back->in(0)->as_If(); | |
| 94 float loop_back_cnt = back_if->_fcnt * back_if->_prob; | |
| 95 | |
| 96 // Now compute a loop exit count | |
| 97 float loop_exit_cnt = 0.0f; | |
| 98 for( uint i = 0; i < _body.size(); i++ ) { | |
| 99 Node *n = _body[i]; | |
| 100 if( n->is_If() ) { | |
| 101 IfNode *iff = n->as_If(); | |
| 102 if( iff->_fcnt != COUNT_UNKNOWN && iff->_prob != PROB_UNKNOWN ) { | |
| 103 Node *exit = is_loop_exit(iff); | |
| 104 if( exit ) { | |
| 105 float exit_prob = iff->_prob; | |
| 106 if (exit->Opcode() == Op_IfFalse) exit_prob = 1.0 - exit_prob; | |
| 107 if (exit_prob > PROB_MIN) { | |
| 108 float exit_cnt = iff->_fcnt * exit_prob; | |
| 109 loop_exit_cnt += exit_cnt; | |
| 110 } | |
| 111 } | |
| 112 } | |
| 113 } | |
| 114 } | |
| 115 if (loop_exit_cnt > 0.0f) { | |
| 116 trip_cnt = (loop_back_cnt + loop_exit_cnt) / loop_exit_cnt; | |
| 117 } else { | |
| 118 // No exit count so use | |
| 119 trip_cnt = loop_back_cnt; | |
| 120 } | |
| 121 } | |
| 122 #ifndef PRODUCT | |
| 123 if (TraceProfileTripCount) { | |
| 124 tty->print_cr("compute_profile_trip_cnt lp: %d cnt: %f\n", head->_idx, trip_cnt); | |
| 125 } | |
| 126 #endif | |
| 127 head->set_profile_trip_cnt(trip_cnt); | |
| 128 } | |
| 129 | |
| 130 //---------------------is_invariant_addition----------------------------- | |
| 131 // Return nonzero index of invariant operand for an Add or Sub | |
| 605 | 132 // of (nonconstant) invariant and variant values. Helper for reassociate_invariants. |
| 0 | 133 int IdealLoopTree::is_invariant_addition(Node* n, PhaseIdealLoop *phase) { |
| 134 int op = n->Opcode(); | |
| 135 if (op == Op_AddI || op == Op_SubI) { | |
| 136 bool in1_invar = this->is_invariant(n->in(1)); | |
| 137 bool in2_invar = this->is_invariant(n->in(2)); | |
| 138 if (in1_invar && !in2_invar) return 1; | |
| 139 if (!in1_invar && in2_invar) return 2; | |
| 140 } | |
| 141 return 0; | |
| 142 } | |
| 143 | |
| 144 //---------------------reassociate_add_sub----------------------------- | |
| 145 // Reassociate invariant add and subtract expressions: | |
| 146 // | |
| 147 // inv1 + (x + inv2) => ( inv1 + inv2) + x | |
| 148 // (x + inv2) + inv1 => ( inv1 + inv2) + x | |
| 149 // inv1 + (x - inv2) => ( inv1 - inv2) + x | |
| 150 // inv1 - (inv2 - x) => ( inv1 - inv2) + x | |
| 151 // (x + inv2) - inv1 => (-inv1 + inv2) + x | |
| 152 // (x - inv2) + inv1 => ( inv1 - inv2) + x | |
| 153 // (x - inv2) - inv1 => (-inv1 - inv2) + x | |
| 154 // inv1 + (inv2 - x) => ( inv1 + inv2) - x | |
| 155 // inv1 - (x - inv2) => ( inv1 + inv2) - x | |
| 156 // (inv2 - x) + inv1 => ( inv1 + inv2) - x | |
| 157 // (inv2 - x) - inv1 => (-inv1 + inv2) - x | |
| 158 // inv1 - (x + inv2) => ( inv1 - inv2) - x | |
| 159 // | |
| 160 Node* IdealLoopTree::reassociate_add_sub(Node* n1, PhaseIdealLoop *phase) { | |
| 161 if (!n1->is_Add() && !n1->is_Sub() || n1->outcnt() == 0) return NULL; | |
| 162 if (is_invariant(n1)) return NULL; | |
| 163 int inv1_idx = is_invariant_addition(n1, phase); | |
| 164 if (!inv1_idx) return NULL; | |
| 165 // Don't mess with add of constant (igvn moves them to expression tree root.) | |
| 166 if (n1->is_Add() && n1->in(2)->is_Con()) return NULL; | |
| 167 Node* inv1 = n1->in(inv1_idx); | |
| 168 Node* n2 = n1->in(3 - inv1_idx); | |
| 169 int inv2_idx = is_invariant_addition(n2, phase); | |
| 170 if (!inv2_idx) return NULL; | |
| 171 Node* x = n2->in(3 - inv2_idx); | |
| 172 Node* inv2 = n2->in(inv2_idx); | |
| 173 | |
| 174 bool neg_x = n2->is_Sub() && inv2_idx == 1; | |
| 175 bool neg_inv2 = n2->is_Sub() && inv2_idx == 2; | |
| 176 bool neg_inv1 = n1->is_Sub() && inv1_idx == 2; | |
| 177 if (n1->is_Sub() && inv1_idx == 1) { | |
| 178 neg_x = !neg_x; | |
| 179 neg_inv2 = !neg_inv2; | |
| 180 } | |
| 181 Node* inv1_c = phase->get_ctrl(inv1); | |
| 182 Node* inv2_c = phase->get_ctrl(inv2); | |
| 183 Node* n_inv1; | |
| 184 if (neg_inv1) { | |
| 185 Node *zero = phase->_igvn.intcon(0); | |
| 186 phase->set_ctrl(zero, phase->C->root()); | |
| 187 n_inv1 = new (phase->C, 3) SubINode(zero, inv1); | |
| 188 phase->register_new_node(n_inv1, inv1_c); | |
| 189 } else { | |
| 190 n_inv1 = inv1; | |
| 191 } | |
| 192 Node* inv; | |
| 193 if (neg_inv2) { | |
| 194 inv = new (phase->C, 3) SubINode(n_inv1, inv2); | |
| 195 } else { | |
| 196 inv = new (phase->C, 3) AddINode(n_inv1, inv2); | |
| 197 } | |
| 198 phase->register_new_node(inv, phase->get_early_ctrl(inv)); | |
| 199 | |
| 200 Node* addx; | |
| 201 if (neg_x) { | |
| 202 addx = new (phase->C, 3) SubINode(inv, x); | |
| 203 } else { | |
| 204 addx = new (phase->C, 3) AddINode(x, inv); | |
| 205 } | |
| 206 phase->register_new_node(addx, phase->get_ctrl(x)); | |
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207 phase->_igvn.replace_node(n1, addx); |
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208 assert(phase->get_loop(phase->get_ctrl(n1)) == this, ""); |
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209 _body.yank(n1); |
| 0 | 210 return addx; |
| 211 } | |
| 212 | |
| 213 //---------------------reassociate_invariants----------------------------- | |
| 214 // Reassociate invariant expressions: | |
| 215 void IdealLoopTree::reassociate_invariants(PhaseIdealLoop *phase) { | |
| 216 for (int i = _body.size() - 1; i >= 0; i--) { | |
| 217 Node *n = _body.at(i); | |
| 218 for (int j = 0; j < 5; j++) { | |
| 219 Node* nn = reassociate_add_sub(n, phase); | |
| 220 if (nn == NULL) break; | |
| 221 n = nn; // again | |
| 222 }; | |
| 223 } | |
| 224 } | |
| 225 | |
| 226 //------------------------------policy_peeling--------------------------------- | |
| 227 // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can | |
| 228 // make some loop-invariant test (usually a null-check) happen before the loop. | |
| 229 bool IdealLoopTree::policy_peeling( PhaseIdealLoop *phase ) const { | |
| 230 Node *test = ((IdealLoopTree*)this)->tail(); | |
| 231 int body_size = ((IdealLoopTree*)this)->_body.size(); | |
| 232 int uniq = phase->C->unique(); | |
| 233 // Peeling does loop cloning which can result in O(N^2) node construction | |
| 234 if( body_size > 255 /* Prevent overflow for large body_size */ | |
| 235 || (body_size * body_size + uniq > MaxNodeLimit) ) { | |
| 236 return false; // too large to safely clone | |
| 237 } | |
| 238 while( test != _head ) { // Scan till run off top of loop | |
| 239 if( test->is_If() ) { // Test? | |
| 240 Node *ctrl = phase->get_ctrl(test->in(1)); | |
| 241 if (ctrl->is_top()) | |
| 242 return false; // Found dead test on live IF? No peeling! | |
| 243 // Standard IF only has one input value to check for loop invariance | |
| 244 assert( test->Opcode() == Op_If || test->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
| 245 // Condition is not a member of this loop? | |
| 246 if( !is_member(phase->get_loop(ctrl)) && | |
| 247 is_loop_exit(test) ) | |
| 248 return true; // Found reason to peel! | |
| 249 } | |
| 250 // Walk up dominators to loop _head looking for test which is | |
| 251 // executed on every path thru loop. | |
| 252 test = phase->idom(test); | |
| 253 } | |
| 254 return false; | |
| 255 } | |
| 256 | |
| 257 //------------------------------peeled_dom_test_elim--------------------------- | |
| 258 // If we got the effect of peeling, either by actually peeling or by making | |
| 259 // a pre-loop which must execute at least once, we can remove all | |
| 260 // loop-invariant dominated tests in the main body. | |
| 261 void PhaseIdealLoop::peeled_dom_test_elim( IdealLoopTree *loop, Node_List &old_new ) { | |
| 262 bool progress = true; | |
| 263 while( progress ) { | |
| 264 progress = false; // Reset for next iteration | |
| 265 Node *prev = loop->_head->in(LoopNode::LoopBackControl);//loop->tail(); | |
| 266 Node *test = prev->in(0); | |
| 267 while( test != loop->_head ) { // Scan till run off top of loop | |
| 268 | |
| 269 int p_op = prev->Opcode(); | |
| 270 if( (p_op == Op_IfFalse || p_op == Op_IfTrue) && | |
| 271 test->is_If() && // Test? | |
| 272 !test->in(1)->is_Con() && // And not already obvious? | |
| 273 // Condition is not a member of this loop? | |
| 274 !loop->is_member(get_loop(get_ctrl(test->in(1))))){ | |
| 275 // Walk loop body looking for instances of this test | |
| 276 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
| 277 Node *n = loop->_body.at(i); | |
| 278 if( n->is_If() && n->in(1) == test->in(1) /*&& n != loop->tail()->in(0)*/ ) { | |
| 279 // IfNode was dominated by version in peeled loop body | |
| 280 progress = true; | |
| 281 dominated_by( old_new[prev->_idx], n ); | |
| 282 } | |
| 283 } | |
| 284 } | |
| 285 prev = test; | |
| 286 test = idom(test); | |
| 287 } // End of scan tests in loop | |
| 288 | |
| 289 } // End of while( progress ) | |
| 290 } | |
| 291 | |
| 292 //------------------------------do_peeling------------------------------------- | |
| 293 // Peel the first iteration of the given loop. | |
| 294 // Step 1: Clone the loop body. The clone becomes the peeled iteration. | |
| 295 // The pre-loop illegally has 2 control users (old & new loops). | |
| 296 // Step 2: Make the old-loop fall-in edges point to the peeled iteration. | |
| 297 // Do this by making the old-loop fall-in edges act as if they came | |
| 298 // around the loopback from the prior iteration (follow the old-loop | |
| 299 // backedges) and then map to the new peeled iteration. This leaves | |
| 300 // the pre-loop with only 1 user (the new peeled iteration), but the | |
| 301 // peeled-loop backedge has 2 users. | |
| 302 // Step 3: Cut the backedge on the clone (so its not a loop) and remove the | |
| 303 // extra backedge user. | |
| 2445 | 304 // |
| 305 // orig | |
| 306 // | |
| 307 // stmt1 | |
| 308 // | | |
| 309 // v | |
| 310 // loop predicate | |
| 311 // | | |
| 312 // v | |
| 313 // loop<----+ | |
| 314 // | | | |
| 315 // stmt2 | | |
| 316 // | | | |
| 317 // v | | |
| 318 // if ^ | |
| 319 // / \ | | |
| 320 // / \ | | |
| 321 // v v | | |
| 322 // false true | | |
| 323 // / \ | | |
| 324 // / ----+ | |
| 325 // | | |
| 326 // v | |
| 327 // exit | |
| 328 // | |
| 329 // | |
| 330 // after clone loop | |
| 331 // | |
| 332 // stmt1 | |
| 333 // | | |
| 334 // v | |
| 335 // loop predicate | |
| 336 // / \ | |
| 337 // clone / \ orig | |
| 338 // / \ | |
| 339 // / \ | |
| 340 // v v | |
| 341 // +---->loop clone loop<----+ | |
| 342 // | | | | | |
| 343 // | stmt2 clone stmt2 | | |
| 344 // | | | | | |
| 345 // | v v | | |
| 346 // ^ if clone If ^ | |
| 347 // | / \ / \ | | |
| 348 // | / \ / \ | | |
| 349 // | v v v v | | |
| 350 // | true false false true | | |
| 351 // | / \ / \ | | |
| 352 // +---- \ / ----+ | |
| 353 // \ / | |
| 354 // 1v v2 | |
| 355 // region | |
| 356 // | | |
| 357 // v | |
| 358 // exit | |
| 359 // | |
| 360 // | |
| 361 // after peel and predicate move | |
| 362 // | |
| 363 // stmt1 | |
| 364 // / | |
| 365 // / | |
| 366 // clone / orig | |
| 367 // / | |
| 368 // / +----------+ | |
| 369 // / | | | |
| 370 // / loop predicate | | |
| 371 // / | | | |
| 372 // v v | | |
| 373 // TOP-->loop clone loop<----+ | | |
| 374 // | | | | | |
| 375 // stmt2 clone stmt2 | | | |
| 376 // | | | ^ | |
| 377 // v v | | | |
| 378 // if clone If ^ | | |
| 379 // / \ / \ | | | |
| 380 // / \ / \ | | | |
| 381 // v v v v | | | |
| 382 // true false false true | | | |
| 383 // | \ / \ | | | |
| 384 // | \ / ----+ ^ | |
| 385 // | \ / | | |
| 386 // | 1v v2 | | |
| 387 // v region | | |
| 388 // | | | | |
| 389 // | v | | |
| 390 // | exit | | |
| 391 // | | | |
| 392 // +--------------->-----------------+ | |
| 393 // | |
| 394 // | |
| 395 // final graph | |
| 396 // | |
| 397 // stmt1 | |
| 398 // | | |
| 399 // v | |
| 400 // stmt2 clone | |
| 401 // | | |
| 402 // v | |
| 403 // if clone | |
| 404 // / | | |
| 405 // / | | |
| 406 // v v | |
| 407 // false true | |
| 408 // | | | |
| 409 // | v | |
| 410 // | loop predicate | |
| 411 // | | | |
| 412 // | v | |
| 413 // | loop<----+ | |
| 414 // | | | | |
| 415 // | stmt2 | | |
| 416 // | | | | |
| 417 // | v | | |
| 418 // v if ^ | |
| 419 // | / \ | | |
| 420 // | / \ | | |
| 421 // | v v | | |
| 422 // | false true | | |
| 423 // | | \ | | |
| 424 // v v --+ | |
| 425 // region | |
| 426 // | | |
| 427 // v | |
| 428 // exit | |
| 429 // | |
| 0 | 430 void PhaseIdealLoop::do_peeling( IdealLoopTree *loop, Node_List &old_new ) { |
| 431 | |
| 432 C->set_major_progress(); | |
| 433 // Peeling a 'main' loop in a pre/main/post situation obfuscates the | |
| 434 // 'pre' loop from the main and the 'pre' can no longer have it's | |
| 435 // iterations adjusted. Therefore, we need to declare this loop as | |
| 436 // no longer a 'main' loop; it will need new pre and post loops before | |
| 437 // we can do further RCE. | |
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438 #ifndef PRODUCT |
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439 if (TraceLoopOpts) { |
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440 tty->print("Peel "); |
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441 loop->dump_head(); |
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442 } |
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443 #endif |
| 2445 | 444 Node* head = loop->_head; |
| 445 bool counted_loop = head->is_CountedLoop(); | |
| 446 if (counted_loop) { | |
| 447 CountedLoopNode *cl = head->as_CountedLoop(); | |
| 0 | 448 assert(cl->trip_count() > 0, "peeling a fully unrolled loop"); |
| 449 cl->set_trip_count(cl->trip_count() - 1); | |
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450 if (cl->is_main_loop()) { |
| 0 | 451 cl->set_normal_loop(); |
| 452 #ifndef PRODUCT | |
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453 if (PrintOpto && VerifyLoopOptimizations) { |
| 0 | 454 tty->print("Peeling a 'main' loop; resetting to 'normal' "); |
| 455 loop->dump_head(); | |
| 456 } | |
| 457 #endif | |
| 458 } | |
| 459 } | |
| 2445 | 460 Node* entry = head->in(LoopNode::EntryControl); |
| 0 | 461 |
| 462 // Step 1: Clone the loop body. The clone becomes the peeled iteration. | |
| 463 // The pre-loop illegally has 2 control users (old & new loops). | |
| 2445 | 464 clone_loop( loop, old_new, dom_depth(head) ); |
| 0 | 465 |
| 466 // Step 2: Make the old-loop fall-in edges point to the peeled iteration. | |
| 467 // Do this by making the old-loop fall-in edges act as if they came | |
| 468 // around the loopback from the prior iteration (follow the old-loop | |
| 469 // backedges) and then map to the new peeled iteration. This leaves | |
| 470 // the pre-loop with only 1 user (the new peeled iteration), but the | |
| 471 // peeled-loop backedge has 2 users. | |
| 2445 | 472 Node* new_exit_value = old_new[head->in(LoopNode::LoopBackControl)->_idx]; |
| 473 new_exit_value = move_loop_predicates(entry, new_exit_value); | |
| 474 _igvn.hash_delete(head); | |
| 475 head->set_req(LoopNode::EntryControl, new_exit_value); | |
| 476 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { | |
| 477 Node* old = head->fast_out(j); | |
| 478 if (old->in(0) == loop->_head && old->req() == 3 && old->is_Phi()) { | |
| 479 new_exit_value = old_new[old->in(LoopNode::LoopBackControl)->_idx]; | |
| 480 if (!new_exit_value ) // Backedge value is ALSO loop invariant? | |
| 0 | 481 // Then loop body backedge value remains the same. |
| 482 new_exit_value = old->in(LoopNode::LoopBackControl); | |
| 483 _igvn.hash_delete(old); | |
| 484 old->set_req(LoopNode::EntryControl, new_exit_value); | |
| 485 } | |
| 486 } | |
| 487 | |
| 488 | |
| 489 // Step 3: Cut the backedge on the clone (so its not a loop) and remove the | |
| 490 // extra backedge user. | |
| 2445 | 491 Node* new_head = old_new[head->_idx]; |
| 492 _igvn.hash_delete(new_head); | |
| 493 new_head->set_req(LoopNode::LoopBackControl, C->top()); | |
| 494 for (DUIterator_Fast j2max, j2 = new_head->fast_outs(j2max); j2 < j2max; j2++) { | |
| 495 Node* use = new_head->fast_out(j2); | |
| 496 if (use->in(0) == new_head && use->req() == 3 && use->is_Phi()) { | |
| 0 | 497 _igvn.hash_delete(use); |
| 498 use->set_req(LoopNode::LoopBackControl, C->top()); | |
| 499 } | |
| 500 } | |
| 501 | |
| 502 | |
| 503 // Step 4: Correct dom-depth info. Set to loop-head depth. | |
| 2445 | 504 int dd = dom_depth(head); |
| 505 set_idom(head, head->in(1), dd); | |
| 0 | 506 for (uint j3 = 0; j3 < loop->_body.size(); j3++) { |
| 507 Node *old = loop->_body.at(j3); | |
| 508 Node *nnn = old_new[old->_idx]; | |
| 509 if (!has_ctrl(nnn)) | |
| 510 set_idom(nnn, idom(nnn), dd-1); | |
| 511 // While we're at it, remove any SafePoints from the peeled code | |
| 2445 | 512 if (old->Opcode() == Op_SafePoint) { |
| 0 | 513 Node *nnn = old_new[old->_idx]; |
| 514 lazy_replace(nnn,nnn->in(TypeFunc::Control)); | |
| 515 } | |
| 516 } | |
| 517 | |
| 518 // Now force out all loop-invariant dominating tests. The optimizer | |
| 519 // finds some, but we _know_ they are all useless. | |
| 520 peeled_dom_test_elim(loop,old_new); | |
| 521 | |
| 522 loop->record_for_igvn(); | |
| 523 } | |
| 524 | |
| 525 //------------------------------policy_maximally_unroll------------------------ | |
| 526 // Return exact loop trip count, or 0 if not maximally unrolling | |
| 527 bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const { | |
| 528 CountedLoopNode *cl = _head->as_CountedLoop(); | |
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529 assert(cl->is_normal_loop(), ""); |
| 0 | 530 |
| 531 Node *init_n = cl->init_trip(); | |
| 532 Node *limit_n = cl->limit(); | |
| 533 | |
| 534 // Non-constant bounds | |
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535 if (init_n == NULL || !init_n->is_Con() || |
| 0 | 536 limit_n == NULL || !limit_n->is_Con() || |
| 537 // protect against stride not being a constant | |
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538 !cl->stride_is_con()) { |
| 0 | 539 return false; |
| 540 } | |
| 541 int init = init_n->get_int(); | |
| 542 int limit = limit_n->get_int(); | |
| 543 int span = limit - init; | |
| 544 int stride = cl->stride_con(); | |
| 545 | |
| 546 if (init >= limit || stride > span) { | |
| 547 // return a false (no maximally unroll) and the regular unroll/peel | |
| 548 // route will make a small mess which CCP will fold away. | |
| 549 return false; | |
| 550 } | |
| 551 uint trip_count = span/stride; // trip_count can be greater than 2 Gig. | |
| 552 assert( (int)trip_count*stride == span, "must divide evenly" ); | |
| 553 | |
| 554 // Real policy: if we maximally unroll, does it get too big? | |
| 555 // Allow the unrolled mess to get larger than standard loop | |
| 556 // size. After all, it will no longer be a loop. | |
| 557 uint body_size = _body.size(); | |
| 558 uint unroll_limit = (uint)LoopUnrollLimit * 4; | |
| 559 assert( (intx)unroll_limit == LoopUnrollLimit * 4, "LoopUnrollLimit must fit in 32bits"); | |
| 560 cl->set_trip_count(trip_count); | |
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561 if (trip_count > unroll_limit || body_size > unroll_limit) { |
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562 return false; |
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563 } |
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564 |
| 2417 | 565 // Currently we don't have policy to optimize one iteration loops. |
| 566 // Maximally unrolling transformation is used for that: | |
| 567 // it is peeled and the original loop become non reachable (dead). | |
| 568 if (trip_count == 1) | |
| 569 return true; | |
| 570 | |
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571 // Do not unroll a loop with String intrinsics code. |
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572 // String intrinsics are large and have loops. |
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573 for (uint k = 0; k < _body.size(); k++) { |
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574 Node* n = _body.at(k); |
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575 switch (n->Opcode()) { |
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576 case Op_StrComp: |
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577 case Op_StrEquals: |
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578 case Op_StrIndexOf: |
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579 case Op_AryEq: { |
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580 return false; |
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581 } |
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582 } // switch |
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583 } |
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584 |
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585 if (body_size <= unroll_limit) { |
| 0 | 586 uint new_body_size = body_size * trip_count; |
| 587 if (new_body_size <= unroll_limit && | |
| 588 body_size == new_body_size / trip_count && | |
| 589 // Unrolling can result in a large amount of node construction | |
| 590 new_body_size < MaxNodeLimit - phase->C->unique()) { | |
| 591 return true; // maximally unroll | |
| 592 } | |
| 593 } | |
| 594 | |
| 595 return false; // Do not maximally unroll | |
| 596 } | |
| 597 | |
| 598 | |
| 599 //------------------------------policy_unroll---------------------------------- | |
| 600 // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if | |
| 601 // the loop is a CountedLoop and the body is small enough. | |
| 602 bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const { | |
| 603 | |
| 604 CountedLoopNode *cl = _head->as_CountedLoop(); | |
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605 assert(cl->is_normal_loop() || cl->is_main_loop(), ""); |
| 0 | 606 |
| 607 // protect against stride not being a constant | |
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608 if (!cl->stride_is_con()) return false; |
| 0 | 609 |
| 610 // protect against over-unrolling | |
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611 if (cl->trip_count() <= 1) return false; |
| 0 | 612 |
| 613 int future_unroll_ct = cl->unrolled_count() * 2; | |
| 614 | |
| 615 // Don't unroll if the next round of unrolling would push us | |
| 616 // over the expected trip count of the loop. One is subtracted | |
| 617 // from the expected trip count because the pre-loop normally | |
| 618 // executes 1 iteration. | |
| 619 if (UnrollLimitForProfileCheck > 0 && | |
| 620 cl->profile_trip_cnt() != COUNT_UNKNOWN && | |
| 621 future_unroll_ct > UnrollLimitForProfileCheck && | |
| 622 (float)future_unroll_ct > cl->profile_trip_cnt() - 1.0) { | |
| 623 return false; | |
| 624 } | |
| 625 | |
| 626 // When unroll count is greater than LoopUnrollMin, don't unroll if: | |
| 627 // the residual iterations are more than 10% of the trip count | |
| 628 // and rounds of "unroll,optimize" are not making significant progress | |
| 629 // Progress defined as current size less than 20% larger than previous size. | |
| 630 if (UseSuperWord && cl->node_count_before_unroll() > 0 && | |
| 631 future_unroll_ct > LoopUnrollMin && | |
| 632 (future_unroll_ct - 1) * 10.0 > cl->profile_trip_cnt() && | |
| 633 1.2 * cl->node_count_before_unroll() < (double)_body.size()) { | |
| 634 return false; | |
| 635 } | |
| 636 | |
| 637 Node *init_n = cl->init_trip(); | |
| 638 Node *limit_n = cl->limit(); | |
| 639 // Non-constant bounds. | |
| 640 // Protect against over-unrolling when init or/and limit are not constant | |
| 641 // (so that trip_count's init value is maxint) but iv range is known. | |
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642 if (init_n == NULL || !init_n->is_Con() || |
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643 limit_n == NULL || !limit_n->is_Con()) { |
| 0 | 644 Node* phi = cl->phi(); |
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645 if (phi != NULL) { |
| 0 | 646 assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi."); |
| 647 const TypeInt* iv_type = phase->_igvn.type(phi)->is_int(); | |
| 648 int next_stride = cl->stride_con() * 2; // stride after this unroll | |
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649 if (next_stride > 0) { |
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650 if (iv_type->_lo + next_stride <= iv_type->_lo || // overflow |
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651 iv_type->_lo + next_stride > iv_type->_hi) { |
| 0 | 652 return false; // over-unrolling |
| 653 } | |
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654 } else if (next_stride < 0) { |
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655 if (iv_type->_hi + next_stride >= iv_type->_hi || // overflow |
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656 iv_type->_hi + next_stride < iv_type->_lo) { |
| 0 | 657 return false; // over-unrolling |
| 658 } | |
| 659 } | |
| 660 } | |
| 661 } | |
| 662 | |
| 663 // Adjust body_size to determine if we unroll or not | |
| 664 uint body_size = _body.size(); | |
| 665 // Key test to unroll CaffeineMark's Logic test | |
| 666 int xors_in_loop = 0; | |
| 667 // Also count ModL, DivL and MulL which expand mightly | |
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668 for (uint k = 0; k < _body.size(); k++) { |
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669 Node* n = _body.at(k); |
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670 switch (n->Opcode()) { |
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671 case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test |
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672 case Op_ModL: body_size += 30; break; |
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673 case Op_DivL: body_size += 30; break; |
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674 case Op_MulL: body_size += 10; break; |
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675 case Op_StrComp: |
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676 case Op_StrEquals: |
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677 case Op_StrIndexOf: |
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678 case Op_AryEq: { |
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679 // Do not unroll a loop with String intrinsics code. |
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680 // String intrinsics are large and have loops. |
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681 return false; |
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682 } |
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683 } // switch |
| 0 | 684 } |
| 685 | |
| 686 // Check for being too big | |
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687 if (body_size > (uint)LoopUnrollLimit) { |
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688 if (xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true; |
| 0 | 689 // Normal case: loop too big |
| 690 return false; | |
| 691 } | |
| 692 | |
| 693 // Check for stride being a small enough constant | |
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694 if (abs(cl->stride_con()) > (1<<3)) return false; |
| 0 | 695 |
| 696 // Unroll once! (Each trip will soon do double iterations) | |
| 697 return true; | |
| 698 } | |
| 699 | |
| 700 //------------------------------policy_align----------------------------------- | |
| 701 // Return TRUE or FALSE if the loop should be cache-line aligned. Gather the | |
| 702 // expression that does the alignment. Note that only one array base can be | |
| 605 | 703 // aligned in a loop (unless the VM guarantees mutual alignment). Note that |
| 0 | 704 // if we vectorize short memory ops into longer memory ops, we may want to |
| 705 // increase alignment. | |
| 706 bool IdealLoopTree::policy_align( PhaseIdealLoop *phase ) const { | |
| 707 return false; | |
| 708 } | |
| 709 | |
| 710 //------------------------------policy_range_check----------------------------- | |
| 711 // Return TRUE or FALSE if the loop should be range-check-eliminated. | |
| 712 // Actually we do iteration-splitting, a more powerful form of RCE. | |
| 713 bool IdealLoopTree::policy_range_check( PhaseIdealLoop *phase ) const { | |
| 714 if( !RangeCheckElimination ) return false; | |
| 715 | |
| 716 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 717 // If we unrolled with no intention of doing RCE and we later | |
| 718 // changed our minds, we got no pre-loop. Either we need to | |
| 719 // make a new pre-loop, or we gotta disallow RCE. | |
| 720 if( cl->is_main_no_pre_loop() ) return false; // Disallowed for now. | |
| 721 Node *trip_counter = cl->phi(); | |
| 722 | |
| 723 // Check loop body for tests of trip-counter plus loop-invariant vs | |
| 724 // loop-invariant. | |
| 725 for( uint i = 0; i < _body.size(); i++ ) { | |
| 726 Node *iff = _body[i]; | |
| 727 if( iff->Opcode() == Op_If ) { // Test? | |
| 728 | |
| 729 // Comparing trip+off vs limit | |
| 730 Node *bol = iff->in(1); | |
| 731 if( bol->req() != 2 ) continue; // dead constant test | |
| 1172 | 732 if (!bol->is_Bool()) { |
| 733 assert(UseLoopPredicate && bol->Opcode() == Op_Conv2B, "predicate check only"); | |
| 734 continue; | |
| 735 } | |
| 0 | 736 Node *cmp = bol->in(1); |
| 737 | |
| 738 Node *rc_exp = cmp->in(1); | |
| 739 Node *limit = cmp->in(2); | |
| 740 | |
| 741 Node *limit_c = phase->get_ctrl(limit); | |
| 742 if( limit_c == phase->C->top() ) | |
| 743 return false; // Found dead test on live IF? No RCE! | |
| 744 if( is_member(phase->get_loop(limit_c) ) ) { | |
| 745 // Compare might have operands swapped; commute them | |
| 746 rc_exp = cmp->in(2); | |
| 747 limit = cmp->in(1); | |
| 748 limit_c = phase->get_ctrl(limit); | |
| 749 if( is_member(phase->get_loop(limit_c) ) ) | |
| 750 continue; // Both inputs are loop varying; cannot RCE | |
| 751 } | |
| 752 | |
| 753 if (!phase->is_scaled_iv_plus_offset(rc_exp, trip_counter, NULL, NULL)) { | |
| 754 continue; | |
| 755 } | |
| 756 // Yeah! Found a test like 'trip+off vs limit' | |
| 757 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
| 758 // we need loop unswitching instead of iteration splitting. | |
| 759 if( is_loop_exit(iff) ) | |
| 760 return true; // Found reason to split iterations | |
| 761 } // End of is IF | |
| 762 } | |
| 763 | |
| 764 return false; | |
| 765 } | |
| 766 | |
| 767 //------------------------------policy_peel_only------------------------------- | |
| 768 // Return TRUE or FALSE if the loop should NEVER be RCE'd or aligned. Useful | |
| 769 // for unrolling loops with NO array accesses. | |
| 770 bool IdealLoopTree::policy_peel_only( PhaseIdealLoop *phase ) const { | |
| 771 | |
| 772 for( uint i = 0; i < _body.size(); i++ ) | |
| 773 if( _body[i]->is_Mem() ) | |
| 774 return false; | |
| 775 | |
| 776 // No memory accesses at all! | |
| 777 return true; | |
| 778 } | |
| 779 | |
| 780 //------------------------------clone_up_backedge_goo-------------------------- | |
| 781 // If Node n lives in the back_ctrl block and cannot float, we clone a private | |
| 782 // version of n in preheader_ctrl block and return that, otherwise return n. | |
| 783 Node *PhaseIdealLoop::clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n ) { | |
| 784 if( get_ctrl(n) != back_ctrl ) return n; | |
| 785 | |
| 786 Node *x = NULL; // If required, a clone of 'n' | |
| 787 // Check for 'n' being pinned in the backedge. | |
| 788 if( n->in(0) && n->in(0) == back_ctrl ) { | |
| 789 x = n->clone(); // Clone a copy of 'n' to preheader | |
| 790 x->set_req( 0, preheader_ctrl ); // Fix x's control input to preheader | |
| 791 } | |
| 792 | |
| 793 // Recursive fixup any other input edges into x. | |
| 794 // If there are no changes we can just return 'n', otherwise | |
| 795 // we need to clone a private copy and change it. | |
| 796 for( uint i = 1; i < n->req(); i++ ) { | |
| 797 Node *g = clone_up_backedge_goo( back_ctrl, preheader_ctrl, n->in(i) ); | |
| 798 if( g != n->in(i) ) { | |
| 799 if( !x ) | |
| 800 x = n->clone(); | |
| 801 x->set_req(i, g); | |
| 802 } | |
| 803 } | |
| 804 if( x ) { // x can legally float to pre-header location | |
| 805 register_new_node( x, preheader_ctrl ); | |
| 806 return x; | |
| 807 } else { // raise n to cover LCA of uses | |
| 808 set_ctrl( n, find_non_split_ctrl(back_ctrl->in(0)) ); | |
| 809 } | |
| 810 return n; | |
| 811 } | |
| 812 | |
| 813 //------------------------------insert_pre_post_loops-------------------------- | |
| 814 // Insert pre and post loops. If peel_only is set, the pre-loop can not have | |
| 815 // more iterations added. It acts as a 'peel' only, no lower-bound RCE, no | |
| 816 // alignment. Useful to unroll loops that do no array accesses. | |
| 817 void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ) { | |
| 818 | |
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819 #ifndef PRODUCT |
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820 if (TraceLoopOpts) { |
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821 if (peel_only) |
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822 tty->print("PeelMainPost "); |
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823 else |
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824 tty->print("PreMainPost "); |
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825 loop->dump_head(); |
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826 } |
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827 #endif |
| 0 | 828 C->set_major_progress(); |
| 829 | |
| 830 // Find common pieces of the loop being guarded with pre & post loops | |
| 831 CountedLoopNode *main_head = loop->_head->as_CountedLoop(); | |
| 832 assert( main_head->is_normal_loop(), "" ); | |
| 833 CountedLoopEndNode *main_end = main_head->loopexit(); | |
| 834 assert( main_end->outcnt() == 2, "1 true, 1 false path only" ); | |
| 835 uint dd_main_head = dom_depth(main_head); | |
| 836 uint max = main_head->outcnt(); | |
| 837 | |
| 838 Node *pre_header= main_head->in(LoopNode::EntryControl); | |
| 839 Node *init = main_head->init_trip(); | |
| 840 Node *incr = main_end ->incr(); | |
| 841 Node *limit = main_end ->limit(); | |
| 842 Node *stride = main_end ->stride(); | |
| 843 Node *cmp = main_end ->cmp_node(); | |
| 844 BoolTest::mask b_test = main_end->test_trip(); | |
| 845 | |
| 846 // Need only 1 user of 'bol' because I will be hacking the loop bounds. | |
| 847 Node *bol = main_end->in(CountedLoopEndNode::TestValue); | |
| 848 if( bol->outcnt() != 1 ) { | |
| 849 bol = bol->clone(); | |
| 850 register_new_node(bol,main_end->in(CountedLoopEndNode::TestControl)); | |
| 851 _igvn.hash_delete(main_end); | |
| 852 main_end->set_req(CountedLoopEndNode::TestValue, bol); | |
| 853 } | |
| 854 // Need only 1 user of 'cmp' because I will be hacking the loop bounds. | |
| 855 if( cmp->outcnt() != 1 ) { | |
| 856 cmp = cmp->clone(); | |
| 857 register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl)); | |
| 858 _igvn.hash_delete(bol); | |
| 859 bol->set_req(1, cmp); | |
| 860 } | |
| 861 | |
| 862 //------------------------------ | |
| 863 // Step A: Create Post-Loop. | |
| 864 Node* main_exit = main_end->proj_out(false); | |
| 865 assert( main_exit->Opcode() == Op_IfFalse, "" ); | |
| 866 int dd_main_exit = dom_depth(main_exit); | |
| 867 | |
| 868 // Step A1: Clone the loop body. The clone becomes the post-loop. The main | |
| 869 // loop pre-header illegally has 2 control users (old & new loops). | |
| 870 clone_loop( loop, old_new, dd_main_exit ); | |
| 871 assert( old_new[main_end ->_idx]->Opcode() == Op_CountedLoopEnd, "" ); | |
| 872 CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop(); | |
| 873 post_head->set_post_loop(main_head); | |
| 874 | |
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875 // Reduce the post-loop trip count. |
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876 CountedLoopEndNode* post_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
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877 post_end->_prob = PROB_FAIR; |
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878 |
| 0 | 879 // Build the main-loop normal exit. |
| 880 IfFalseNode *new_main_exit = new (C, 1) IfFalseNode(main_end); | |
| 881 _igvn.register_new_node_with_optimizer( new_main_exit ); | |
| 882 set_idom(new_main_exit, main_end, dd_main_exit ); | |
| 883 set_loop(new_main_exit, loop->_parent); | |
| 884 | |
| 885 // Step A2: Build a zero-trip guard for the post-loop. After leaving the | |
| 886 // main-loop, the post-loop may not execute at all. We 'opaque' the incr | |
| 887 // (the main-loop trip-counter exit value) because we will be changing | |
| 888 // the exit value (via unrolling) so we cannot constant-fold away the zero | |
| 889 // trip guard until all unrolling is done. | |
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890 Node *zer_opaq = new (C, 2) Opaque1Node(C, incr); |
| 0 | 891 Node *zer_cmp = new (C, 3) CmpINode( zer_opaq, limit ); |
| 892 Node *zer_bol = new (C, 2) BoolNode( zer_cmp, b_test ); | |
| 893 register_new_node( zer_opaq, new_main_exit ); | |
| 894 register_new_node( zer_cmp , new_main_exit ); | |
| 895 register_new_node( zer_bol , new_main_exit ); | |
| 896 | |
| 897 // Build the IfNode | |
| 898 IfNode *zer_iff = new (C, 2) IfNode( new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN ); | |
| 899 _igvn.register_new_node_with_optimizer( zer_iff ); | |
| 900 set_idom(zer_iff, new_main_exit, dd_main_exit); | |
| 901 set_loop(zer_iff, loop->_parent); | |
| 902 | |
| 903 // Plug in the false-path, taken if we need to skip post-loop | |
| 904 _igvn.hash_delete( main_exit ); | |
| 905 main_exit->set_req(0, zer_iff); | |
| 906 _igvn._worklist.push(main_exit); | |
| 907 set_idom(main_exit, zer_iff, dd_main_exit); | |
| 908 set_idom(main_exit->unique_out(), zer_iff, dd_main_exit); | |
| 909 // Make the true-path, must enter the post loop | |
| 910 Node *zer_taken = new (C, 1) IfTrueNode( zer_iff ); | |
| 911 _igvn.register_new_node_with_optimizer( zer_taken ); | |
| 912 set_idom(zer_taken, zer_iff, dd_main_exit); | |
| 913 set_loop(zer_taken, loop->_parent); | |
| 914 // Plug in the true path | |
| 915 _igvn.hash_delete( post_head ); | |
| 916 post_head->set_req(LoopNode::EntryControl, zer_taken); | |
| 917 set_idom(post_head, zer_taken, dd_main_exit); | |
| 918 | |
| 919 // Step A3: Make the fall-in values to the post-loop come from the | |
| 920 // fall-out values of the main-loop. | |
| 921 for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) { | |
| 922 Node* main_phi = main_head->fast_out(i); | |
| 923 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0 ) { | |
| 924 Node *post_phi = old_new[main_phi->_idx]; | |
| 925 Node *fallmain = clone_up_backedge_goo(main_head->back_control(), | |
| 926 post_head->init_control(), | |
| 927 main_phi->in(LoopNode::LoopBackControl)); | |
| 928 _igvn.hash_delete(post_phi); | |
| 929 post_phi->set_req( LoopNode::EntryControl, fallmain ); | |
| 930 } | |
| 931 } | |
| 932 | |
| 933 // Update local caches for next stanza | |
| 934 main_exit = new_main_exit; | |
| 935 | |
| 936 | |
| 937 //------------------------------ | |
| 938 // Step B: Create Pre-Loop. | |
| 939 | |
| 940 // Step B1: Clone the loop body. The clone becomes the pre-loop. The main | |
| 941 // loop pre-header illegally has 2 control users (old & new loops). | |
| 942 clone_loop( loop, old_new, dd_main_head ); | |
| 943 CountedLoopNode* pre_head = old_new[main_head->_idx]->as_CountedLoop(); | |
| 944 CountedLoopEndNode* pre_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); | |
| 945 pre_head->set_pre_loop(main_head); | |
| 946 Node *pre_incr = old_new[incr->_idx]; | |
| 947 | |
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948 // Reduce the pre-loop trip count. |
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949 pre_end->_prob = PROB_FAIR; |
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950 |
| 0 | 951 // Find the pre-loop normal exit. |
| 952 Node* pre_exit = pre_end->proj_out(false); | |
| 953 assert( pre_exit->Opcode() == Op_IfFalse, "" ); | |
| 954 IfFalseNode *new_pre_exit = new (C, 1) IfFalseNode(pre_end); | |
| 955 _igvn.register_new_node_with_optimizer( new_pre_exit ); | |
| 956 set_idom(new_pre_exit, pre_end, dd_main_head); | |
| 957 set_loop(new_pre_exit, loop->_parent); | |
| 958 | |
| 959 // Step B2: Build a zero-trip guard for the main-loop. After leaving the | |
| 960 // pre-loop, the main-loop may not execute at all. Later in life this | |
| 961 // zero-trip guard will become the minimum-trip guard when we unroll | |
| 962 // the main-loop. | |
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963 Node *min_opaq = new (C, 2) Opaque1Node(C, limit); |
| 0 | 964 Node *min_cmp = new (C, 3) CmpINode( pre_incr, min_opaq ); |
| 965 Node *min_bol = new (C, 2) BoolNode( min_cmp, b_test ); | |
| 966 register_new_node( min_opaq, new_pre_exit ); | |
| 967 register_new_node( min_cmp , new_pre_exit ); | |
| 968 register_new_node( min_bol , new_pre_exit ); | |
| 969 | |
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970 // Build the IfNode (assume the main-loop is executed always). |
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971 IfNode *min_iff = new (C, 2) IfNode( new_pre_exit, min_bol, PROB_ALWAYS, COUNT_UNKNOWN ); |
| 0 | 972 _igvn.register_new_node_with_optimizer( min_iff ); |
| 973 set_idom(min_iff, new_pre_exit, dd_main_head); | |
| 974 set_loop(min_iff, loop->_parent); | |
| 975 | |
| 976 // Plug in the false-path, taken if we need to skip main-loop | |
| 977 _igvn.hash_delete( pre_exit ); | |
| 978 pre_exit->set_req(0, min_iff); | |
| 979 set_idom(pre_exit, min_iff, dd_main_head); | |
| 980 set_idom(pre_exit->unique_out(), min_iff, dd_main_head); | |
| 981 // Make the true-path, must enter the main loop | |
| 982 Node *min_taken = new (C, 1) IfTrueNode( min_iff ); | |
| 983 _igvn.register_new_node_with_optimizer( min_taken ); | |
| 984 set_idom(min_taken, min_iff, dd_main_head); | |
| 985 set_loop(min_taken, loop->_parent); | |
| 986 // Plug in the true path | |
| 987 _igvn.hash_delete( main_head ); | |
| 988 main_head->set_req(LoopNode::EntryControl, min_taken); | |
| 989 set_idom(main_head, min_taken, dd_main_head); | |
| 990 | |
| 991 // Step B3: Make the fall-in values to the main-loop come from the | |
| 992 // fall-out values of the pre-loop. | |
| 993 for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) { | |
| 994 Node* main_phi = main_head->fast_out(i2); | |
| 995 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) { | |
| 996 Node *pre_phi = old_new[main_phi->_idx]; | |
| 997 Node *fallpre = clone_up_backedge_goo(pre_head->back_control(), | |
| 998 main_head->init_control(), | |
| 999 pre_phi->in(LoopNode::LoopBackControl)); | |
| 1000 _igvn.hash_delete(main_phi); | |
| 1001 main_phi->set_req( LoopNode::EntryControl, fallpre ); | |
| 1002 } | |
| 1003 } | |
| 1004 | |
| 1005 // Step B4: Shorten the pre-loop to run only 1 iteration (for now). | |
| 1006 // RCE and alignment may change this later. | |
| 1007 Node *cmp_end = pre_end->cmp_node(); | |
| 1008 assert( cmp_end->in(2) == limit, "" ); | |
| 1009 Node *pre_limit = new (C, 3) AddINode( init, stride ); | |
| 1010 | |
| 1011 // Save the original loop limit in this Opaque1 node for | |
| 1012 // use by range check elimination. | |
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1013 Node *pre_opaq = new (C, 3) Opaque1Node(C, pre_limit, limit); |
| 0 | 1014 |
| 1015 register_new_node( pre_limit, pre_head->in(0) ); | |
| 1016 register_new_node( pre_opaq , pre_head->in(0) ); | |
| 1017 | |
| 1018 // Since no other users of pre-loop compare, I can hack limit directly | |
| 1019 assert( cmp_end->outcnt() == 1, "no other users" ); | |
| 1020 _igvn.hash_delete(cmp_end); | |
| 1021 cmp_end->set_req(2, peel_only ? pre_limit : pre_opaq); | |
| 1022 | |
| 1023 // Special case for not-equal loop bounds: | |
| 1024 // Change pre loop test, main loop test, and the | |
| 1025 // main loop guard test to use lt or gt depending on stride | |
| 1026 // direction: | |
| 1027 // positive stride use < | |
| 1028 // negative stride use > | |
| 1029 | |
| 1030 if (pre_end->in(CountedLoopEndNode::TestValue)->as_Bool()->_test._test == BoolTest::ne) { | |
| 1031 | |
| 1032 BoolTest::mask new_test = (main_end->stride_con() > 0) ? BoolTest::lt : BoolTest::gt; | |
| 1033 // Modify pre loop end condition | |
| 1034 Node* pre_bol = pre_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
| 1035 BoolNode* new_bol0 = new (C, 2) BoolNode(pre_bol->in(1), new_test); | |
| 1036 register_new_node( new_bol0, pre_head->in(0) ); | |
| 1037 _igvn.hash_delete(pre_end); | |
| 1038 pre_end->set_req(CountedLoopEndNode::TestValue, new_bol0); | |
| 1039 // Modify main loop guard condition | |
| 1040 assert(min_iff->in(CountedLoopEndNode::TestValue) == min_bol, "guard okay"); | |
| 1041 BoolNode* new_bol1 = new (C, 2) BoolNode(min_bol->in(1), new_test); | |
| 1042 register_new_node( new_bol1, new_pre_exit ); | |
| 1043 _igvn.hash_delete(min_iff); | |
| 1044 min_iff->set_req(CountedLoopEndNode::TestValue, new_bol1); | |
| 1045 // Modify main loop end condition | |
| 1046 BoolNode* main_bol = main_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
| 1047 BoolNode* new_bol2 = new (C, 2) BoolNode(main_bol->in(1), new_test); | |
| 1048 register_new_node( new_bol2, main_end->in(CountedLoopEndNode::TestControl) ); | |
| 1049 _igvn.hash_delete(main_end); | |
| 1050 main_end->set_req(CountedLoopEndNode::TestValue, new_bol2); | |
| 1051 } | |
| 1052 | |
| 1053 // Flag main loop | |
| 1054 main_head->set_main_loop(); | |
| 1055 if( peel_only ) main_head->set_main_no_pre_loop(); | |
| 1056 | |
| 1057 // It's difficult to be precise about the trip-counts | |
| 1058 // for the pre/post loops. They are usually very short, | |
| 1059 // so guess that 4 trips is a reasonable value. | |
| 1060 post_head->set_profile_trip_cnt(4.0); | |
| 1061 pre_head->set_profile_trip_cnt(4.0); | |
| 1062 | |
| 1063 // Now force out all loop-invariant dominating tests. The optimizer | |
| 1064 // finds some, but we _know_ they are all useless. | |
| 1065 peeled_dom_test_elim(loop,old_new); | |
| 1066 } | |
| 1067 | |
| 1068 //------------------------------is_invariant----------------------------- | |
| 1069 // Return true if n is invariant | |
| 1070 bool IdealLoopTree::is_invariant(Node* n) const { | |
| 1172 | 1071 Node *n_c = _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; |
| 0 | 1072 if (n_c->is_top()) return false; |
| 1073 return !is_member(_phase->get_loop(n_c)); | |
| 1074 } | |
| 1075 | |
| 1076 | |
| 1077 //------------------------------do_unroll-------------------------------------- | |
| 1078 // Unroll the loop body one step - make each trip do 2 iterations. | |
| 1079 void PhaseIdealLoop::do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ) { | |
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1080 assert(LoopUnrollLimit, ""); |
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1081 CountedLoopNode *loop_head = loop->_head->as_CountedLoop(); |
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1082 CountedLoopEndNode *loop_end = loop_head->loopexit(); |
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1083 assert(loop_end, ""); |
| 0 | 1084 #ifndef PRODUCT |
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1085 if (PrintOpto && VerifyLoopOptimizations) { |
| 0 | 1086 tty->print("Unrolling "); |
| 1087 loop->dump_head(); | |
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1088 } else if (TraceLoopOpts) { |
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1089 tty->print("Unroll %d ", loop_head->unrolled_count()*2); |
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1090 loop->dump_head(); |
| 0 | 1091 } |
| 1092 #endif | |
| 1093 | |
| 1094 // Remember loop node count before unrolling to detect | |
| 1095 // if rounds of unroll,optimize are making progress | |
| 1096 loop_head->set_node_count_before_unroll(loop->_body.size()); | |
| 1097 | |
| 1098 Node *ctrl = loop_head->in(LoopNode::EntryControl); | |
| 1099 Node *limit = loop_head->limit(); | |
| 1100 Node *init = loop_head->init_trip(); | |
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1101 Node *stride = loop_head->stride(); |
| 0 | 1102 |
| 1103 Node *opaq = NULL; | |
| 1104 if( adjust_min_trip ) { // If not maximally unrolling, need adjustment | |
| 1105 assert( loop_head->is_main_loop(), "" ); | |
| 1106 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
| 1107 Node *iff = ctrl->in(0); | |
| 1108 assert( iff->Opcode() == Op_If, "" ); | |
| 1109 Node *bol = iff->in(1); | |
| 1110 assert( bol->Opcode() == Op_Bool, "" ); | |
| 1111 Node *cmp = bol->in(1); | |
| 1112 assert( cmp->Opcode() == Op_CmpI, "" ); | |
| 1113 opaq = cmp->in(2); | |
| 1114 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
| 1115 // optimized away and then another round of loop opts attempted. | |
| 1116 // We can not optimize this particular loop in that case. | |
| 1117 if( opaq->Opcode() != Op_Opaque1 ) | |
| 1118 return; // Cannot find pre-loop! Bail out! | |
| 1119 } | |
| 1120 | |
| 1121 C->set_major_progress(); | |
| 1122 | |
| 1123 // Adjust max trip count. The trip count is intentionally rounded | |
| 1124 // down here (e.g. 15-> 7-> 3-> 1) because if we unwittingly over-unroll, | |
| 1125 // the main, unrolled, part of the loop will never execute as it is protected | |
| 1126 // by the min-trip test. See bug 4834191 for a case where we over-unrolled | |
| 1127 // and later determined that part of the unrolled loop was dead. | |
| 1128 loop_head->set_trip_count(loop_head->trip_count() / 2); | |
| 1129 | |
| 1130 // Double the count of original iterations in the unrolled loop body. | |
| 1131 loop_head->double_unrolled_count(); | |
| 1132 | |
| 1133 // ----------- | |
| 1134 // Step 2: Cut back the trip counter for an unroll amount of 2. | |
| 1135 // Loop will normally trip (limit - init)/stride_con. Since it's a | |
| 1136 // CountedLoop this is exact (stride divides limit-init exactly). | |
| 1137 // We are going to double the loop body, so we want to knock off any | |
| 1138 // odd iteration: (trip_cnt & ~1). Then back compute a new limit. | |
| 1139 Node *span = new (C, 3) SubINode( limit, init ); | |
| 1140 register_new_node( span, ctrl ); | |
|
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1141 Node *trip = new (C, 3) DivINode( 0, span, stride ); |
| 0 | 1142 register_new_node( trip, ctrl ); |
| 1143 Node *mtwo = _igvn.intcon(-2); | |
| 1144 set_ctrl(mtwo, C->root()); | |
| 1145 Node *rond = new (C, 3) AndINode( trip, mtwo ); | |
| 1146 register_new_node( rond, ctrl ); | |
|
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1147 Node *spn2 = new (C, 3) MulINode( rond, stride ); |
| 0 | 1148 register_new_node( spn2, ctrl ); |
| 1149 Node *lim2 = new (C, 3) AddINode( spn2, init ); | |
| 1150 register_new_node( lim2, ctrl ); | |
| 1151 | |
| 1152 // Hammer in the new limit | |
| 1153 Node *ctrl2 = loop_end->in(0); | |
| 1154 Node *cmp2 = new (C, 3) CmpINode( loop_head->incr(), lim2 ); | |
| 1155 register_new_node( cmp2, ctrl2 ); | |
| 1156 Node *bol2 = new (C, 2) BoolNode( cmp2, loop_end->test_trip() ); | |
| 1157 register_new_node( bol2, ctrl2 ); | |
| 1158 _igvn.hash_delete(loop_end); | |
| 1159 loop_end->set_req(CountedLoopEndNode::TestValue, bol2); | |
| 1160 | |
| 1161 // Step 3: Find the min-trip test guaranteed before a 'main' loop. | |
| 1162 // Make it a 1-trip test (means at least 2 trips). | |
| 1163 if( adjust_min_trip ) { | |
| 1164 // Guard test uses an 'opaque' node which is not shared. Hence I | |
| 1165 // can edit it's inputs directly. Hammer in the new limit for the | |
| 1166 // minimum-trip guard. | |
| 1167 assert( opaq->outcnt() == 1, "" ); | |
| 1168 _igvn.hash_delete(opaq); | |
| 1169 opaq->set_req(1, lim2); | |
| 1170 } | |
| 1171 | |
| 1172 // --------- | |
| 1173 // Step 4: Clone the loop body. Move it inside the loop. This loop body | |
| 1174 // represents the odd iterations; since the loop trips an even number of | |
| 1175 // times its backedge is never taken. Kill the backedge. | |
| 1176 uint dd = dom_depth(loop_head); | |
| 1177 clone_loop( loop, old_new, dd ); | |
| 1178 | |
| 1179 // Make backedges of the clone equal to backedges of the original. | |
| 1180 // Make the fall-in from the original come from the fall-out of the clone. | |
| 1181 for (DUIterator_Fast jmax, j = loop_head->fast_outs(jmax); j < jmax; j++) { | |
| 1182 Node* phi = loop_head->fast_out(j); | |
| 1183 if( phi->is_Phi() && phi->in(0) == loop_head && phi->outcnt() > 0 ) { | |
| 1184 Node *newphi = old_new[phi->_idx]; | |
| 1185 _igvn.hash_delete( phi ); | |
| 1186 _igvn.hash_delete( newphi ); | |
| 1187 | |
| 1188 phi ->set_req(LoopNode:: EntryControl, newphi->in(LoopNode::LoopBackControl)); | |
| 1189 newphi->set_req(LoopNode::LoopBackControl, phi ->in(LoopNode::LoopBackControl)); | |
| 1190 phi ->set_req(LoopNode::LoopBackControl, C->top()); | |
| 1191 } | |
| 1192 } | |
| 1193 Node *clone_head = old_new[loop_head->_idx]; | |
| 1194 _igvn.hash_delete( clone_head ); | |
| 1195 loop_head ->set_req(LoopNode:: EntryControl, clone_head->in(LoopNode::LoopBackControl)); | |
| 1196 clone_head->set_req(LoopNode::LoopBackControl, loop_head ->in(LoopNode::LoopBackControl)); | |
| 1197 loop_head ->set_req(LoopNode::LoopBackControl, C->top()); | |
| 1198 loop->_head = clone_head; // New loop header | |
| 1199 | |
| 1200 set_idom(loop_head, loop_head ->in(LoopNode::EntryControl), dd); | |
| 1201 set_idom(clone_head, clone_head->in(LoopNode::EntryControl), dd); | |
| 1202 | |
| 1203 // Kill the clone's backedge | |
| 1204 Node *newcle = old_new[loop_end->_idx]; | |
| 1205 _igvn.hash_delete( newcle ); | |
| 1206 Node *one = _igvn.intcon(1); | |
| 1207 set_ctrl(one, C->root()); | |
| 1208 newcle->set_req(1, one); | |
| 1209 // Force clone into same loop body | |
| 1210 uint max = loop->_body.size(); | |
| 1211 for( uint k = 0; k < max; k++ ) { | |
| 1212 Node *old = loop->_body.at(k); | |
| 1213 Node *nnn = old_new[old->_idx]; | |
| 1214 loop->_body.push(nnn); | |
| 1215 if (!has_ctrl(old)) | |
| 1216 set_loop(nnn, loop); | |
| 1217 } | |
|
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1218 |
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1219 loop->record_for_igvn(); |
| 0 | 1220 } |
| 1221 | |
| 1222 //------------------------------do_maximally_unroll---------------------------- | |
| 1223 | |
| 1224 void PhaseIdealLoop::do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ) { | |
| 1225 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
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1226 assert(cl->trip_count() > 0, ""); |
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1227 #ifndef PRODUCT |
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1228 if (TraceLoopOpts) { |
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1229 tty->print("MaxUnroll %d ", cl->trip_count()); |
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1230 loop->dump_head(); |
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1231 } |
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1232 #endif |
| 0 | 1233 |
| 1234 // If loop is tripping an odd number of times, peel odd iteration | |
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1235 if ((cl->trip_count() & 1) == 1) { |
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1236 do_peeling(loop, old_new); |
| 0 | 1237 } |
| 1238 | |
| 1239 // Now its tripping an even number of times remaining. Double loop body. | |
| 1240 // Do not adjust pre-guards; they are not needed and do not exist. | |
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1241 if (cl->trip_count() > 0) { |
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1242 do_unroll(loop, old_new, false); |
| 0 | 1243 } |
| 1244 } | |
| 1245 | |
| 1246 //------------------------------dominates_backedge--------------------------------- | |
| 1247 // Returns true if ctrl is executed on every complete iteration | |
| 1248 bool IdealLoopTree::dominates_backedge(Node* ctrl) { | |
| 1249 assert(ctrl->is_CFG(), "must be control"); | |
| 1250 Node* backedge = _head->as_Loop()->in(LoopNode::LoopBackControl); | |
| 1251 return _phase->dom_lca_internal(ctrl, backedge) == ctrl; | |
| 1252 } | |
| 1253 | |
| 1254 //------------------------------add_constraint--------------------------------- | |
| 1255 // Constrain the main loop iterations so the condition: | |
| 1256 // scale_con * I + offset < limit | |
| 1257 // always holds true. That is, either increase the number of iterations in | |
| 1258 // the pre-loop or the post-loop until the condition holds true in the main | |
| 1259 // loop. Stride, scale, offset and limit are all loop invariant. Further, | |
| 1260 // stride and scale are constants (offset and limit often are). | |
| 1261 void PhaseIdealLoop::add_constraint( int stride_con, int scale_con, Node *offset, Node *limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ) { | |
| 1262 | |
| 1263 // Compute "I :: (limit-offset)/scale_con" | |
| 1264 Node *con = new (C, 3) SubINode( limit, offset ); | |
| 1265 register_new_node( con, pre_ctrl ); | |
| 1266 Node *scale = _igvn.intcon(scale_con); | |
| 1267 set_ctrl(scale, C->root()); | |
| 1268 Node *X = new (C, 3) DivINode( 0, con, scale ); | |
| 1269 register_new_node( X, pre_ctrl ); | |
| 1270 | |
| 1271 // For positive stride, the pre-loop limit always uses a MAX function | |
| 1272 // and the main loop a MIN function. For negative stride these are | |
| 1273 // reversed. | |
| 1274 | |
| 1275 // Also for positive stride*scale the affine function is increasing, so the | |
| 1276 // pre-loop must check for underflow and the post-loop for overflow. | |
| 1277 // Negative stride*scale reverses this; pre-loop checks for overflow and | |
| 1278 // post-loop for underflow. | |
| 1279 if( stride_con*scale_con > 0 ) { | |
| 1280 // Compute I < (limit-offset)/scale_con | |
| 1281 // Adjust main-loop last iteration to be MIN/MAX(main_loop,X) | |
| 1282 *main_limit = (stride_con > 0) | |
| 1283 ? (Node*)(new (C, 3) MinINode( *main_limit, X )) | |
| 1284 : (Node*)(new (C, 3) MaxINode( *main_limit, X )); | |
| 1285 register_new_node( *main_limit, pre_ctrl ); | |
| 1286 | |
| 1287 } else { | |
| 1288 // Compute (limit-offset)/scale_con + SGN(-scale_con) <= I | |
| 1289 // Add the negation of the main-loop constraint to the pre-loop. | |
| 1290 // See footnote [++] below for a derivation of the limit expression. | |
| 1291 Node *incr = _igvn.intcon(scale_con > 0 ? -1 : 1); | |
| 1292 set_ctrl(incr, C->root()); | |
| 1293 Node *adj = new (C, 3) AddINode( X, incr ); | |
| 1294 register_new_node( adj, pre_ctrl ); | |
| 1295 *pre_limit = (scale_con > 0) | |
| 1296 ? (Node*)new (C, 3) MinINode( *pre_limit, adj ) | |
| 1297 : (Node*)new (C, 3) MaxINode( *pre_limit, adj ); | |
| 1298 register_new_node( *pre_limit, pre_ctrl ); | |
| 1299 | |
| 1300 // [++] Here's the algebra that justifies the pre-loop limit expression: | |
| 1301 // | |
| 1302 // NOT( scale_con * I + offset < limit ) | |
| 1303 // == | |
| 1304 // scale_con * I + offset >= limit | |
| 1305 // == | |
| 1306 // SGN(scale_con) * I >= (limit-offset)/|scale_con| | |
| 1307 // == | |
| 1308 // (limit-offset)/|scale_con| <= I * SGN(scale_con) | |
| 1309 // == | |
| 1310 // (limit-offset)/|scale_con|-1 < I * SGN(scale_con) | |
| 1311 // == | |
| 1312 // ( if (scale_con > 0) /*common case*/ | |
| 1313 // (limit-offset)/scale_con - 1 < I | |
| 1314 // else | |
| 1315 // (limit-offset)/scale_con + 1 > I | |
| 1316 // ) | |
| 1317 // ( if (scale_con > 0) /*common case*/ | |
| 1318 // (limit-offset)/scale_con + SGN(-scale_con) < I | |
| 1319 // else | |
| 1320 // (limit-offset)/scale_con + SGN(-scale_con) > I | |
| 1321 } | |
| 1322 } | |
| 1323 | |
| 1324 | |
| 1325 //------------------------------is_scaled_iv--------------------------------- | |
| 1326 // Return true if exp is a constant times an induction var | |
| 1327 bool PhaseIdealLoop::is_scaled_iv(Node* exp, Node* iv, int* p_scale) { | |
| 1328 if (exp == iv) { | |
| 1329 if (p_scale != NULL) { | |
| 1330 *p_scale = 1; | |
| 1331 } | |
| 1332 return true; | |
| 1333 } | |
| 1334 int opc = exp->Opcode(); | |
| 1335 if (opc == Op_MulI) { | |
| 1336 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
| 1337 if (p_scale != NULL) { | |
| 1338 *p_scale = exp->in(2)->get_int(); | |
| 1339 } | |
| 1340 return true; | |
| 1341 } | |
| 1342 if (exp->in(2) == iv && exp->in(1)->is_Con()) { | |
| 1343 if (p_scale != NULL) { | |
| 1344 *p_scale = exp->in(1)->get_int(); | |
| 1345 } | |
| 1346 return true; | |
| 1347 } | |
| 1348 } else if (opc == Op_LShiftI) { | |
| 1349 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
| 1350 if (p_scale != NULL) { | |
| 1351 *p_scale = 1 << exp->in(2)->get_int(); | |
| 1352 } | |
| 1353 return true; | |
| 1354 } | |
| 1355 } | |
| 1356 return false; | |
| 1357 } | |
| 1358 | |
| 1359 //-----------------------------is_scaled_iv_plus_offset------------------------------ | |
| 1360 // Return true if exp is a simple induction variable expression: k1*iv + (invar + k2) | |
| 1361 bool PhaseIdealLoop::is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth) { | |
| 1362 if (is_scaled_iv(exp, iv, p_scale)) { | |
| 1363 if (p_offset != NULL) { | |
| 1364 Node *zero = _igvn.intcon(0); | |
| 1365 set_ctrl(zero, C->root()); | |
| 1366 *p_offset = zero; | |
| 1367 } | |
| 1368 return true; | |
| 1369 } | |
| 1370 int opc = exp->Opcode(); | |
| 1371 if (opc == Op_AddI) { | |
| 1372 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
| 1373 if (p_offset != NULL) { | |
| 1374 *p_offset = exp->in(2); | |
| 1375 } | |
| 1376 return true; | |
| 1377 } | |
| 1378 if (exp->in(2)->is_Con()) { | |
| 1379 Node* offset2 = NULL; | |
| 1380 if (depth < 2 && | |
| 1381 is_scaled_iv_plus_offset(exp->in(1), iv, p_scale, | |
| 1382 p_offset != NULL ? &offset2 : NULL, depth+1)) { | |
| 1383 if (p_offset != NULL) { | |
| 1384 Node *ctrl_off2 = get_ctrl(offset2); | |
| 1385 Node* offset = new (C, 3) AddINode(offset2, exp->in(2)); | |
| 1386 register_new_node(offset, ctrl_off2); | |
| 1387 *p_offset = offset; | |
| 1388 } | |
| 1389 return true; | |
| 1390 } | |
| 1391 } | |
| 1392 } else if (opc == Op_SubI) { | |
| 1393 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
| 1394 if (p_offset != NULL) { | |
| 1395 Node *zero = _igvn.intcon(0); | |
| 1396 set_ctrl(zero, C->root()); | |
| 1397 Node *ctrl_off = get_ctrl(exp->in(2)); | |
| 1398 Node* offset = new (C, 3) SubINode(zero, exp->in(2)); | |
| 1399 register_new_node(offset, ctrl_off); | |
| 1400 *p_offset = offset; | |
| 1401 } | |
| 1402 return true; | |
| 1403 } | |
| 1404 if (is_scaled_iv(exp->in(2), iv, p_scale)) { | |
| 1405 if (p_offset != NULL) { | |
| 1406 *p_scale *= -1; | |
| 1407 *p_offset = exp->in(1); | |
| 1408 } | |
| 1409 return true; | |
| 1410 } | |
| 1411 } | |
| 1412 return false; | |
| 1413 } | |
| 1414 | |
| 1415 //------------------------------do_range_check--------------------------------- | |
| 1416 // Eliminate range-checks and other trip-counter vs loop-invariant tests. | |
| 1417 void PhaseIdealLoop::do_range_check( IdealLoopTree *loop, Node_List &old_new ) { | |
| 1418 #ifndef PRODUCT | |
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1419 if (PrintOpto && VerifyLoopOptimizations) { |
| 0 | 1420 tty->print("Range Check Elimination "); |
| 1421 loop->dump_head(); | |
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1422 } else if (TraceLoopOpts) { |
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1423 tty->print("RangeCheck "); |
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1424 loop->dump_head(); |
| 0 | 1425 } |
| 1426 #endif | |
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1427 assert(RangeCheckElimination, ""); |
| 0 | 1428 CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
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1429 assert(cl->is_main_loop(), ""); |
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1430 |
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1431 // protect against stride not being a constant |
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1432 if (!cl->stride_is_con()) |
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1433 return; |
| 0 | 1434 |
| 1435 // Find the trip counter; we are iteration splitting based on it | |
| 1436 Node *trip_counter = cl->phi(); | |
| 1437 // Find the main loop limit; we will trim it's iterations | |
| 1438 // to not ever trip end tests | |
| 1439 Node *main_limit = cl->limit(); | |
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1440 |
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1441 // Need to find the main-loop zero-trip guard |
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1442 Node *ctrl = cl->in(LoopNode::EntryControl); |
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1443 assert(ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, ""); |
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1444 Node *iffm = ctrl->in(0); |
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1445 assert(iffm->Opcode() == Op_If, ""); |
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1446 Node *bolzm = iffm->in(1); |
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1447 assert(bolzm->Opcode() == Op_Bool, ""); |
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1448 Node *cmpzm = bolzm->in(1); |
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1449 assert(cmpzm->is_Cmp(), ""); |
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1450 Node *opqzm = cmpzm->in(2); |
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1451 // Can not optimize a loop if pre-loop Opaque1 node is optimized |
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1452 // away and then another round of loop opts attempted. |
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1453 if (opqzm->Opcode() != Op_Opaque1) |
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1454 return; |
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1455 assert(opqzm->in(1) == main_limit, "do not understand situation"); |
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1456 |
| 0 | 1457 // Find the pre-loop limit; we will expand it's iterations to |
| 1458 // not ever trip low tests. | |
| 1459 Node *p_f = iffm->in(0); | |
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1460 assert(p_f->Opcode() == Op_IfFalse, ""); |
| 0 | 1461 CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); |
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1462 assert(pre_end->loopnode()->is_pre_loop(), ""); |
| 0 | 1463 Node *pre_opaq1 = pre_end->limit(); |
| 1464 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
| 1465 // optimized away and then another round of loop opts attempted. | |
| 1466 // We can not optimize this particular loop in that case. | |
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1467 if (pre_opaq1->Opcode() != Op_Opaque1) |
| 0 | 1468 return; |
| 1469 Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1; | |
| 1470 Node *pre_limit = pre_opaq->in(1); | |
| 1471 | |
| 1472 // Where do we put new limit calculations | |
| 1473 Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl); | |
| 1474 | |
| 1475 // Ensure the original loop limit is available from the | |
| 1476 // pre-loop Opaque1 node. | |
| 1477 Node *orig_limit = pre_opaq->original_loop_limit(); | |
|
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1478 if (orig_limit == NULL || _igvn.type(orig_limit) == Type::TOP) |
| 0 | 1479 return; |
| 1480 | |
| 1481 // Must know if its a count-up or count-down loop | |
| 1482 | |
| 1483 int stride_con = cl->stride_con(); | |
| 1484 Node *zero = _igvn.intcon(0); | |
| 1485 Node *one = _igvn.intcon(1); | |
| 1486 set_ctrl(zero, C->root()); | |
| 1487 set_ctrl(one, C->root()); | |
| 1488 | |
| 1489 // Range checks that do not dominate the loop backedge (ie. | |
| 1490 // conditionally executed) can lengthen the pre loop limit beyond | |
| 1491 // the original loop limit. To prevent this, the pre limit is | |
| 1492 // (for stride > 0) MINed with the original loop limit (MAXed | |
| 1493 // stride < 0) when some range_check (rc) is conditionally | |
| 1494 // executed. | |
| 1495 bool conditional_rc = false; | |
| 1496 | |
| 1497 // Check loop body for tests of trip-counter plus loop-invariant vs | |
| 1498 // loop-invariant. | |
| 1499 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
| 1500 Node *iff = loop->_body[i]; | |
| 1501 if( iff->Opcode() == Op_If ) { // Test? | |
| 1502 | |
| 1503 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
| 1504 // we need loop unswitching instead of iteration splitting. | |
| 1505 Node *exit = loop->is_loop_exit(iff); | |
| 1506 if( !exit ) continue; | |
| 1507 int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0; | |
| 1508 | |
| 1509 // Get boolean condition to test | |
| 1510 Node *i1 = iff->in(1); | |
| 1511 if( !i1->is_Bool() ) continue; | |
| 1512 BoolNode *bol = i1->as_Bool(); | |
| 1513 BoolTest b_test = bol->_test; | |
| 1514 // Flip sense of test if exit condition is flipped | |
| 1515 if( flip ) | |
| 1516 b_test = b_test.negate(); | |
| 1517 | |
| 1518 // Get compare | |
| 1519 Node *cmp = bol->in(1); | |
| 1520 | |
| 1521 // Look for trip_counter + offset vs limit | |
| 1522 Node *rc_exp = cmp->in(1); | |
| 1523 Node *limit = cmp->in(2); | |
| 1524 jint scale_con= 1; // Assume trip counter not scaled | |
| 1525 | |
| 1526 Node *limit_c = get_ctrl(limit); | |
| 1527 if( loop->is_member(get_loop(limit_c) ) ) { | |
| 1528 // Compare might have operands swapped; commute them | |
| 1529 b_test = b_test.commute(); | |
| 1530 rc_exp = cmp->in(2); | |
| 1531 limit = cmp->in(1); | |
| 1532 limit_c = get_ctrl(limit); | |
| 1533 if( loop->is_member(get_loop(limit_c) ) ) | |
| 1534 continue; // Both inputs are loop varying; cannot RCE | |
| 1535 } | |
| 1536 // Here we know 'limit' is loop invariant | |
| 1537 | |
| 1538 // 'limit' maybe pinned below the zero trip test (probably from a | |
| 1539 // previous round of rce), in which case, it can't be used in the | |
| 1540 // zero trip test expression which must occur before the zero test's if. | |
| 1541 if( limit_c == ctrl ) { | |
| 1542 continue; // Don't rce this check but continue looking for other candidates. | |
| 1543 } | |
| 1544 | |
| 1545 // Check for scaled induction variable plus an offset | |
| 1546 Node *offset = NULL; | |
| 1547 | |
| 1548 if (!is_scaled_iv_plus_offset(rc_exp, trip_counter, &scale_con, &offset)) { | |
| 1549 continue; | |
| 1550 } | |
| 1551 | |
| 1552 Node *offset_c = get_ctrl(offset); | |
| 1553 if( loop->is_member( get_loop(offset_c) ) ) | |
| 1554 continue; // Offset is not really loop invariant | |
| 1555 // Here we know 'offset' is loop invariant. | |
| 1556 | |
| 1557 // As above for the 'limit', the 'offset' maybe pinned below the | |
| 1558 // zero trip test. | |
| 1559 if( offset_c == ctrl ) { | |
| 1560 continue; // Don't rce this check but continue looking for other candidates. | |
| 1561 } | |
| 1562 | |
| 1563 // At this point we have the expression as: | |
| 1564 // scale_con * trip_counter + offset :: limit | |
| 1565 // where scale_con, offset and limit are loop invariant. Trip_counter | |
| 1566 // monotonically increases by stride_con, a constant. Both (or either) | |
| 1567 // stride_con and scale_con can be negative which will flip about the | |
| 1568 // sense of the test. | |
| 1569 | |
| 1570 // Adjust pre and main loop limits to guard the correct iteration set | |
| 1571 if( cmp->Opcode() == Op_CmpU ) {// Unsigned compare is really 2 tests | |
| 1572 if( b_test._test == BoolTest::lt ) { // Range checks always use lt | |
| 1573 // The overflow limit: scale*I+offset < limit | |
| 1574 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
| 1575 // The underflow limit: 0 <= scale*I+offset. | |
| 1576 // Some math yields: -scale*I-(offset+1) < 0 | |
| 1577 Node *plus_one = new (C, 3) AddINode( offset, one ); | |
| 1578 register_new_node( plus_one, pre_ctrl ); | |
| 1579 Node *neg_offset = new (C, 3) SubINode( zero, plus_one ); | |
| 1580 register_new_node( neg_offset, pre_ctrl ); | |
| 1581 add_constraint( stride_con, -scale_con, neg_offset, zero, pre_ctrl, &pre_limit, &main_limit ); | |
| 1582 if (!conditional_rc) { | |
| 1583 conditional_rc = !loop->dominates_backedge(iff); | |
| 1584 } | |
| 1585 } else { | |
| 1586 #ifndef PRODUCT | |
| 1587 if( PrintOpto ) | |
| 1588 tty->print_cr("missed RCE opportunity"); | |
| 1589 #endif | |
| 1590 continue; // In release mode, ignore it | |
| 1591 } | |
| 1592 } else { // Otherwise work on normal compares | |
| 1593 switch( b_test._test ) { | |
| 1594 case BoolTest::ge: // Convert X >= Y to -X <= -Y | |
| 1595 scale_con = -scale_con; | |
| 1596 offset = new (C, 3) SubINode( zero, offset ); | |
| 1597 register_new_node( offset, pre_ctrl ); | |
| 1598 limit = new (C, 3) SubINode( zero, limit ); | |
| 1599 register_new_node( limit, pre_ctrl ); | |
| 1600 // Fall into LE case | |
| 1601 case BoolTest::le: // Convert X <= Y to X < Y+1 | |
| 1602 limit = new (C, 3) AddINode( limit, one ); | |
| 1603 register_new_node( limit, pre_ctrl ); | |
| 1604 // Fall into LT case | |
| 1605 case BoolTest::lt: | |
| 1606 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
| 1607 if (!conditional_rc) { | |
| 1608 conditional_rc = !loop->dominates_backedge(iff); | |
| 1609 } | |
| 1610 break; | |
| 1611 default: | |
| 1612 #ifndef PRODUCT | |
| 1613 if( PrintOpto ) | |
| 1614 tty->print_cr("missed RCE opportunity"); | |
| 1615 #endif | |
| 1616 continue; // Unhandled case | |
| 1617 } | |
| 1618 } | |
| 1619 | |
| 1620 // Kill the eliminated test | |
| 1621 C->set_major_progress(); | |
| 1622 Node *kill_con = _igvn.intcon( 1-flip ); | |
| 1623 set_ctrl(kill_con, C->root()); | |
| 1624 _igvn.hash_delete(iff); | |
| 1625 iff->set_req(1, kill_con); | |
| 1626 _igvn._worklist.push(iff); | |
| 1627 // Find surviving projection | |
| 1628 assert(iff->is_If(), ""); | |
| 1629 ProjNode* dp = ((IfNode*)iff)->proj_out(1-flip); | |
| 1630 // Find loads off the surviving projection; remove their control edge | |
| 1631 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
| 1632 Node* cd = dp->fast_out(i); // Control-dependent node | |
| 1633 if( cd->is_Load() ) { // Loads can now float around in the loop | |
| 1634 _igvn.hash_delete(cd); | |
| 1635 // Allow the load to float around in the loop, or before it | |
| 1636 // but NOT before the pre-loop. | |
| 1637 cd->set_req(0, ctrl); // ctrl, not NULL | |
| 1638 _igvn._worklist.push(cd); | |
| 1639 --i; | |
| 1640 --imax; | |
| 1641 } | |
| 1642 } | |
| 1643 | |
| 1644 } // End of is IF | |
| 1645 | |
| 1646 } | |
| 1647 | |
| 1648 // Update loop limits | |
| 1649 if (conditional_rc) { | |
| 1650 pre_limit = (stride_con > 0) ? (Node*)new (C,3) MinINode(pre_limit, orig_limit) | |
| 1651 : (Node*)new (C,3) MaxINode(pre_limit, orig_limit); | |
| 1652 register_new_node(pre_limit, pre_ctrl); | |
| 1653 } | |
| 1654 _igvn.hash_delete(pre_opaq); | |
| 1655 pre_opaq->set_req(1, pre_limit); | |
| 1656 | |
| 1657 // Note:: we are making the main loop limit no longer precise; | |
| 1658 // need to round up based on stride. | |
| 1659 if( stride_con != 1 && stride_con != -1 ) { // Cutout for common case | |
| 1660 // "Standard" round-up logic: ([main_limit-init+(y-1)]/y)*y+init | |
| 1661 // Hopefully, compiler will optimize for powers of 2. | |
| 1662 Node *ctrl = get_ctrl(main_limit); | |
| 1663 Node *stride = cl->stride(); | |
| 1664 Node *init = cl->init_trip(); | |
| 1665 Node *span = new (C, 3) SubINode(main_limit,init); | |
| 1666 register_new_node(span,ctrl); | |
| 1667 Node *rndup = _igvn.intcon(stride_con + ((stride_con>0)?-1:1)); | |
| 1668 Node *add = new (C, 3) AddINode(span,rndup); | |
| 1669 register_new_node(add,ctrl); | |
| 1670 Node *div = new (C, 3) DivINode(0,add,stride); | |
| 1671 register_new_node(div,ctrl); | |
| 1672 Node *mul = new (C, 3) MulINode(div,stride); | |
| 1673 register_new_node(mul,ctrl); | |
| 1674 Node *newlim = new (C, 3) AddINode(mul,init); | |
| 1675 register_new_node(newlim,ctrl); | |
| 1676 main_limit = newlim; | |
| 1677 } | |
| 1678 | |
| 1679 Node *main_cle = cl->loopexit(); | |
| 1680 Node *main_bol = main_cle->in(1); | |
| 1681 // Hacking loop bounds; need private copies of exit test | |
| 1682 if( main_bol->outcnt() > 1 ) {// BoolNode shared? | |
| 1683 _igvn.hash_delete(main_cle); | |
| 1684 main_bol = main_bol->clone();// Clone a private BoolNode | |
| 1685 register_new_node( main_bol, main_cle->in(0) ); | |
| 1686 main_cle->set_req(1,main_bol); | |
| 1687 } | |
| 1688 Node *main_cmp = main_bol->in(1); | |
| 1689 if( main_cmp->outcnt() > 1 ) { // CmpNode shared? | |
| 1690 _igvn.hash_delete(main_bol); | |
| 1691 main_cmp = main_cmp->clone();// Clone a private CmpNode | |
| 1692 register_new_node( main_cmp, main_cle->in(0) ); | |
| 1693 main_bol->set_req(1,main_cmp); | |
| 1694 } | |
| 1695 // Hack the now-private loop bounds | |
| 1696 _igvn.hash_delete(main_cmp); | |
| 1697 main_cmp->set_req(2, main_limit); | |
| 1698 _igvn._worklist.push(main_cmp); | |
| 1699 // The OpaqueNode is unshared by design | |
| 1700 _igvn.hash_delete(opqzm); | |
| 1701 assert( opqzm->outcnt() == 1, "cannot hack shared node" ); | |
| 1702 opqzm->set_req(1,main_limit); | |
| 1703 _igvn._worklist.push(opqzm); | |
| 1704 } | |
| 1705 | |
| 1706 //------------------------------DCE_loop_body---------------------------------- | |
| 1707 // Remove simplistic dead code from loop body | |
| 1708 void IdealLoopTree::DCE_loop_body() { | |
| 1709 for( uint i = 0; i < _body.size(); i++ ) | |
| 1710 if( _body.at(i)->outcnt() == 0 ) | |
| 1711 _body.map( i--, _body.pop() ); | |
| 1712 } | |
| 1713 | |
| 1714 | |
| 1715 //------------------------------adjust_loop_exit_prob-------------------------- | |
| 1716 // Look for loop-exit tests with the 50/50 (or worse) guesses from the parsing stage. | |
| 1717 // Replace with a 1-in-10 exit guess. | |
| 1718 void IdealLoopTree::adjust_loop_exit_prob( PhaseIdealLoop *phase ) { | |
| 1719 Node *test = tail(); | |
| 1720 while( test != _head ) { | |
| 1721 uint top = test->Opcode(); | |
| 1722 if( top == Op_IfTrue || top == Op_IfFalse ) { | |
| 1723 int test_con = ((ProjNode*)test)->_con; | |
| 1724 assert(top == (uint)(test_con? Op_IfTrue: Op_IfFalse), "sanity"); | |
| 1725 IfNode *iff = test->in(0)->as_If(); | |
| 1726 if( iff->outcnt() == 2 ) { // Ignore dead tests | |
| 1727 Node *bol = iff->in(1); | |
| 1728 if( bol && bol->req() > 1 && bol->in(1) && | |
| 1729 ((bol->in(1)->Opcode() == Op_StorePConditional ) || | |
|
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1730 (bol->in(1)->Opcode() == Op_StoreIConditional ) || |
| 0 | 1731 (bol->in(1)->Opcode() == Op_StoreLConditional ) || |
| 1732 (bol->in(1)->Opcode() == Op_CompareAndSwapI ) || | |
| 1733 (bol->in(1)->Opcode() == Op_CompareAndSwapL ) || | |
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1734 (bol->in(1)->Opcode() == Op_CompareAndSwapP ) || |
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1735 (bol->in(1)->Opcode() == Op_CompareAndSwapN ))) |
| 0 | 1736 return; // Allocation loops RARELY take backedge |
| 1737 // Find the OTHER exit path from the IF | |
| 1738 Node* ex = iff->proj_out(1-test_con); | |
| 1739 float p = iff->_prob; | |
| 1740 if( !phase->is_member( this, ex ) && iff->_fcnt == COUNT_UNKNOWN ) { | |
| 1741 if( top == Op_IfTrue ) { | |
| 1742 if( p < (PROB_FAIR + PROB_UNLIKELY_MAG(3))) { | |
| 1743 iff->_prob = PROB_STATIC_FREQUENT; | |
| 1744 } | |
| 1745 } else { | |
| 1746 if( p > (PROB_FAIR - PROB_UNLIKELY_MAG(3))) { | |
| 1747 iff->_prob = PROB_STATIC_INFREQUENT; | |
| 1748 } | |
| 1749 } | |
| 1750 } | |
| 1751 } | |
| 1752 } | |
| 1753 test = phase->idom(test); | |
| 1754 } | |
| 1755 } | |
| 1756 | |
| 1757 | |
| 1758 //------------------------------policy_do_remove_empty_loop-------------------- | |
| 1759 // Micro-benchmark spamming. Policy is to always remove empty loops. | |
| 1760 // The 'DO' part is to replace the trip counter with the value it will | |
| 1761 // have on the last iteration. This will break the loop. | |
| 1762 bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) { | |
| 1763 // Minimum size must be empty loop | |
|
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1764 if (_body.size() > 7/*number of nodes in an empty loop*/) |
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1765 return false; |
| 0 | 1766 |
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1767 if (!_head->is_CountedLoop()) |
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1768 return false; // Dead loop |
| 0 | 1769 CountedLoopNode *cl = _head->as_CountedLoop(); |
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1770 if (!cl->loopexit()) |
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1771 return false; // Malformed loop |
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1772 if (!phase->is_member(this, phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)))) |
| 0 | 1773 return false; // Infinite loop |
| 2403 | 1774 |
| 0 | 1775 #ifdef ASSERT |
| 1776 // Ensure only one phi which is the iv. | |
| 1777 Node* iv = NULL; | |
| 1778 for (DUIterator_Fast imax, i = cl->fast_outs(imax); i < imax; i++) { | |
| 1779 Node* n = cl->fast_out(i); | |
| 1780 if (n->Opcode() == Op_Phi) { | |
| 1781 assert(iv == NULL, "Too many phis" ); | |
| 1782 iv = n; | |
| 1783 } | |
| 1784 } | |
| 1785 assert(iv == cl->phi(), "Wrong phi" ); | |
| 1786 #endif | |
| 2403 | 1787 |
| 1788 // main and post loops have explicitly created zero trip guard | |
| 1789 bool needs_guard = !cl->is_main_loop() && !cl->is_post_loop(); | |
| 1790 if (needs_guard) { | |
| 1791 // Check for an obvious zero trip guard. | |
| 2445 | 1792 Node* inctrl = PhaseIdealLoop::skip_loop_predicates(cl->in(LoopNode::EntryControl)); |
| 2403 | 1793 if (inctrl->Opcode() == Op_IfTrue) { |
| 1794 // The test should look like just the backedge of a CountedLoop | |
| 1795 Node* iff = inctrl->in(0); | |
| 1796 if (iff->is_If()) { | |
| 1797 Node* bol = iff->in(1); | |
| 1798 if (bol->is_Bool() && bol->as_Bool()->_test._test == cl->loopexit()->test_trip()) { | |
| 1799 Node* cmp = bol->in(1); | |
| 1800 if (cmp->is_Cmp() && cmp->in(1) == cl->init_trip() && cmp->in(2) == cl->limit()) { | |
| 1801 needs_guard = false; | |
| 1802 } | |
| 1803 } | |
| 1804 } | |
| 1805 } | |
| 1806 } | |
| 1807 | |
| 1808 #ifndef PRODUCT | |
| 1809 if (PrintOpto) { | |
| 1810 tty->print("Removing empty loop with%s zero trip guard", needs_guard ? "out" : ""); | |
| 1811 this->dump_head(); | |
| 1812 } else if (TraceLoopOpts) { | |
| 1813 tty->print("Empty with%s zero trip guard ", needs_guard ? "out" : ""); | |
| 1814 this->dump_head(); | |
| 1815 } | |
| 1816 #endif | |
| 1817 | |
| 1818 if (needs_guard) { | |
| 1819 // Peel the loop to ensure there's a zero trip guard | |
| 1820 Node_List old_new; | |
| 1821 phase->do_peeling(this, old_new); | |
| 1822 } | |
| 1823 | |
| 0 | 1824 // Replace the phi at loop head with the final value of the last |
| 1825 // iteration. Then the CountedLoopEnd will collapse (backedge never | |
| 1826 // taken) and all loop-invariant uses of the exit values will be correct. | |
| 1827 Node *phi = cl->phi(); | |
| 1828 Node *final = new (phase->C, 3) SubINode( cl->limit(), cl->stride() ); | |
| 1829 phase->register_new_node(final,cl->in(LoopNode::EntryControl)); | |
|
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1830 phase->_igvn.replace_node(phi,final); |
| 0 | 1831 phase->C->set_major_progress(); |
| 1832 return true; | |
| 1833 } | |
| 1834 | |
| 1835 | |
| 1836 //============================================================================= | |
| 1837 //------------------------------iteration_split_impl--------------------------- | |
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1838 bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ) { |
| 0 | 1839 // Check and remove empty loops (spam micro-benchmarks) |
| 1840 if( policy_do_remove_empty_loop(phase) ) | |
| 1172 | 1841 return true; // Here we removed an empty loop |
| 0 | 1842 |
| 1843 bool should_peel = policy_peeling(phase); // Should we peel? | |
| 1844 | |
| 1845 bool should_unswitch = policy_unswitching(phase); | |
| 1846 | |
| 1847 // Non-counted loops may be peeled; exactly 1 iteration is peeled. | |
| 1848 // This removes loop-invariant tests (usually null checks). | |
| 1849 if( !_head->is_CountedLoop() ) { // Non-counted loop | |
| 1850 if (PartialPeelLoop && phase->partial_peel(this, old_new)) { | |
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1851 // Partial peel succeeded so terminate this round of loop opts |
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1852 return false; |
| 0 | 1853 } |
| 1854 if( should_peel ) { // Should we peel? | |
| 1855 #ifndef PRODUCT | |
| 1856 if (PrintOpto) tty->print_cr("should_peel"); | |
| 1857 #endif | |
| 1858 phase->do_peeling(this,old_new); | |
| 1859 } else if( should_unswitch ) { | |
| 1860 phase->do_unswitching(this, old_new); | |
| 1861 } | |
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1862 return true; |
| 0 | 1863 } |
| 1864 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 1865 | |
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1866 if( !cl->loopexit() ) return true; // Ignore various kinds of broken loops |
| 0 | 1867 |
| 1868 // Do nothing special to pre- and post- loops | |
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1869 if( cl->is_pre_loop() || cl->is_post_loop() ) return true; |
| 0 | 1870 |
| 1871 // Compute loop trip count from profile data | |
| 1872 compute_profile_trip_cnt(phase); | |
| 1873 | |
| 1874 // Before attempting fancy unrolling, RCE or alignment, see if we want | |
| 1875 // to completely unroll this loop or do loop unswitching. | |
| 1876 if( cl->is_normal_loop() ) { | |
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1877 if (should_unswitch) { |
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1878 phase->do_unswitching(this, old_new); |
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1879 return true; |
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1880 } |
| 0 | 1881 bool should_maximally_unroll = policy_maximally_unroll(phase); |
| 1882 if( should_maximally_unroll ) { | |
| 1883 // Here we did some unrolling and peeling. Eventually we will | |
| 1884 // completely unroll this loop and it will no longer be a loop. | |
| 1885 phase->do_maximally_unroll(this,old_new); | |
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1886 return true; |
| 0 | 1887 } |
| 1888 } | |
| 1889 | |
| 1890 | |
| 1891 // Counted loops may be peeled, may need some iterations run up | |
| 1892 // front for RCE, and may want to align loop refs to a cache | |
| 1893 // line. Thus we clone a full loop up front whose trip count is | |
| 1894 // at least 1 (if peeling), but may be several more. | |
| 1895 | |
| 1896 // The main loop will start cache-line aligned with at least 1 | |
| 1897 // iteration of the unrolled body (zero-trip test required) and | |
| 1898 // will have some range checks removed. | |
| 1899 | |
| 1900 // A post-loop will finish any odd iterations (leftover after | |
| 1901 // unrolling), plus any needed for RCE purposes. | |
| 1902 | |
| 1903 bool should_unroll = policy_unroll(phase); | |
| 1904 | |
| 1905 bool should_rce = policy_range_check(phase); | |
| 1906 | |
| 1907 bool should_align = policy_align(phase); | |
| 1908 | |
| 1909 // If not RCE'ing (iteration splitting) or Aligning, then we do not | |
| 1910 // need a pre-loop. We may still need to peel an initial iteration but | |
| 1911 // we will not be needing an unknown number of pre-iterations. | |
| 1912 // | |
| 1913 // Basically, if may_rce_align reports FALSE first time through, | |
| 1914 // we will not be able to later do RCE or Aligning on this loop. | |
| 1915 bool may_rce_align = !policy_peel_only(phase) || should_rce || should_align; | |
| 1916 | |
| 1917 // If we have any of these conditions (RCE, alignment, unrolling) met, then | |
| 1918 // we switch to the pre-/main-/post-loop model. This model also covers | |
| 1919 // peeling. | |
| 1920 if( should_rce || should_align || should_unroll ) { | |
| 1921 if( cl->is_normal_loop() ) // Convert to 'pre/main/post' loops | |
| 1922 phase->insert_pre_post_loops(this,old_new, !may_rce_align); | |
| 1923 | |
| 1924 // Adjust the pre- and main-loop limits to let the pre and post loops run | |
| 1925 // with full checks, but the main-loop with no checks. Remove said | |
| 1926 // checks from the main body. | |
| 1927 if( should_rce ) | |
| 1928 phase->do_range_check(this,old_new); | |
| 1929 | |
| 1930 // Double loop body for unrolling. Adjust the minimum-trip test (will do | |
| 1931 // twice as many iterations as before) and the main body limit (only do | |
| 1932 // an even number of trips). If we are peeling, we might enable some RCE | |
| 1933 // and we'd rather unroll the post-RCE'd loop SO... do not unroll if | |
| 1934 // peeling. | |
| 1172 | 1935 if( should_unroll && !should_peel ) |
| 1936 phase->do_unroll(this,old_new, true); | |
| 0 | 1937 |
| 1938 // Adjust the pre-loop limits to align the main body | |
| 1939 // iterations. | |
| 1940 if( should_align ) | |
| 1941 Unimplemented(); | |
| 1942 | |
| 1943 } else { // Else we have an unchanged counted loop | |
| 1944 if( should_peel ) // Might want to peel but do nothing else | |
| 1945 phase->do_peeling(this,old_new); | |
| 1946 } | |
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1947 return true; |
| 0 | 1948 } |
| 1949 | |
| 1950 | |
| 1951 //============================================================================= | |
| 1952 //------------------------------iteration_split-------------------------------- | |
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1953 bool IdealLoopTree::iteration_split( PhaseIdealLoop *phase, Node_List &old_new ) { |
| 0 | 1954 // Recursively iteration split nested loops |
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1955 if (_child && !_child->iteration_split(phase, old_new)) |
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1956 return false; |
| 0 | 1957 |
| 1958 // Clean out prior deadwood | |
| 1959 DCE_loop_body(); | |
| 1960 | |
| 1961 | |
| 1962 // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. | |
| 1963 // Replace with a 1-in-10 exit guess. | |
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1964 if (_parent /*not the root loop*/ && |
| 0 | 1965 !_irreducible && |
| 1966 // Also ignore the occasional dead backedge | |
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1967 !tail()->is_top()) { |
| 0 | 1968 adjust_loop_exit_prob(phase); |
| 1969 } | |
| 1970 | |
| 1971 // Gate unrolling, RCE and peeling efforts. | |
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1972 if (!_child && // If not an inner loop, do not split |
| 0 | 1973 !_irreducible && |
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1974 _allow_optimizations && |
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1975 !tail()->is_top()) { // Also ignore the occasional dead backedge |
| 0 | 1976 if (!_has_call) { |
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1977 if (!iteration_split_impl(phase, old_new)) { |
| 1172 | 1978 return false; |
| 1979 } | |
| 0 | 1980 } else if (policy_unswitching(phase)) { |
| 1981 phase->do_unswitching(this, old_new); | |
| 1982 } | |
| 1983 } | |
| 1984 | |
| 1985 // Minor offset re-organization to remove loop-fallout uses of | |
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1986 // trip counter when there was no major reshaping. |
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1987 phase->reorg_offsets(this); |
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1988 |
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1989 if (_next && !_next->iteration_split(phase, old_new)) |
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1990 return false; |
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1991 return true; |
| 0 | 1992 } |
| 1172 | 1993 |
| 1994 | |
| 2445 | 1995 //============================================================================= |
| 1763 | 1996 // Process all the loops in the loop tree and replace any fill |
| 1997 // patterns with an intrisc version. | |
| 1998 bool PhaseIdealLoop::do_intrinsify_fill() { | |
| 1999 bool changed = false; | |
| 2000 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
| 2001 IdealLoopTree* lpt = iter.current(); | |
| 2002 changed |= intrinsify_fill(lpt); | |
| 2003 } | |
| 2004 return changed; | |
| 2005 } | |
| 2006 | |
| 2007 | |
| 2008 // Examine an inner loop looking for a a single store of an invariant | |
| 2009 // value in a unit stride loop, | |
| 2010 bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value, | |
| 2011 Node*& shift, Node*& con) { | |
| 2012 const char* msg = NULL; | |
| 2013 Node* msg_node = NULL; | |
| 2014 | |
| 2015 store_value = NULL; | |
| 2016 con = NULL; | |
| 2017 shift = NULL; | |
| 2018 | |
| 2019 // Process the loop looking for stores. If there are multiple | |
| 2020 // stores or extra control flow give at this point. | |
| 2021 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
| 2022 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
| 2023 Node* n = lpt->_body.at(i); | |
| 2024 if (n->outcnt() == 0) continue; // Ignore dead | |
| 2025 if (n->is_Store()) { | |
| 2026 if (store != NULL) { | |
| 2027 msg = "multiple stores"; | |
| 2028 break; | |
| 2029 } | |
| 2030 int opc = n->Opcode(); | |
| 2031 if (opc == Op_StoreP || opc == Op_StoreN || opc == Op_StoreCM) { | |
| 2032 msg = "oop fills not handled"; | |
| 2033 break; | |
| 2034 } | |
| 2035 Node* value = n->in(MemNode::ValueIn); | |
| 2036 if (!lpt->is_invariant(value)) { | |
| 2037 msg = "variant store value"; | |
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2038 } else if (!_igvn.type(n->in(MemNode::Address))->isa_aryptr()) { |
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2039 msg = "not array address"; |
| 1763 | 2040 } |
| 2041 store = n; | |
| 2042 store_value = value; | |
| 2043 } else if (n->is_If() && n != head->loopexit()) { | |
| 2044 msg = "extra control flow"; | |
| 2045 msg_node = n; | |
| 2046 } | |
| 2047 } | |
| 2048 | |
| 2049 if (store == NULL) { | |
| 2050 // No store in loop | |
| 2051 return false; | |
| 2052 } | |
| 2053 | |
| 2054 if (msg == NULL && head->stride_con() != 1) { | |
| 2055 // could handle negative strides too | |
| 2056 if (head->stride_con() < 0) { | |
| 2057 msg = "negative stride"; | |
| 2058 } else { | |
| 2059 msg = "non-unit stride"; | |
| 2060 } | |
| 2061 } | |
| 2062 | |
| 2063 if (msg == NULL && !store->in(MemNode::Address)->is_AddP()) { | |
| 2064 msg = "can't handle store address"; | |
| 2065 msg_node = store->in(MemNode::Address); | |
| 2066 } | |
| 2067 | |
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2068 if (msg == NULL && |
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2069 (!store->in(MemNode::Memory)->is_Phi() || |
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2070 store->in(MemNode::Memory)->in(LoopNode::LoopBackControl) != store)) { |
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2071 msg = "store memory isn't proper phi"; |
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2072 msg_node = store->in(MemNode::Memory); |
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2073 } |
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2074 |
| 1763 | 2075 // Make sure there is an appropriate fill routine |
| 2076 BasicType t = store->as_Mem()->memory_type(); | |
| 2077 const char* fill_name; | |
| 2078 if (msg == NULL && | |
| 2079 StubRoutines::select_fill_function(t, false, fill_name) == NULL) { | |
| 2080 msg = "unsupported store"; | |
| 2081 msg_node = store; | |
| 2082 } | |
| 2083 | |
| 2084 if (msg != NULL) { | |
| 2085 #ifndef PRODUCT | |
| 2086 if (TraceOptimizeFill) { | |
| 2087 tty->print_cr("not fill intrinsic candidate: %s", msg); | |
| 2088 if (msg_node != NULL) msg_node->dump(); | |
| 2089 } | |
| 2090 #endif | |
| 2091 return false; | |
| 2092 } | |
| 2093 | |
| 2094 // Make sure the address expression can be handled. It should be | |
| 2095 // head->phi * elsize + con. head->phi might have a ConvI2L. | |
| 2096 Node* elements[4]; | |
| 2097 Node* conv = NULL; | |
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2098 bool found_index = false; |
| 1763 | 2099 int count = store->in(MemNode::Address)->as_AddP()->unpack_offsets(elements, ARRAY_SIZE(elements)); |
| 2100 for (int e = 0; e < count; e++) { | |
| 2101 Node* n = elements[e]; | |
| 2102 if (n->is_Con() && con == NULL) { | |
| 2103 con = n; | |
| 2104 } else if (n->Opcode() == Op_LShiftX && shift == NULL) { | |
| 2105 Node* value = n->in(1); | |
| 2106 #ifdef _LP64 | |
| 2107 if (value->Opcode() == Op_ConvI2L) { | |
| 2108 conv = value; | |
| 2109 value = value->in(1); | |
| 2110 } | |
| 2111 #endif | |
| 2112 if (value != head->phi()) { | |
| 2113 msg = "unhandled shift in address"; | |
| 2114 } else { | |
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2115 found_index = true; |
| 1763 | 2116 shift = n; |
| 2117 assert(type2aelembytes(store->as_Mem()->memory_type(), true) == 1 << shift->in(2)->get_int(), "scale should match"); | |
| 2118 } | |
| 2119 } else if (n->Opcode() == Op_ConvI2L && conv == NULL) { | |
| 2120 if (n->in(1) == head->phi()) { | |
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2121 found_index = true; |
| 1763 | 2122 conv = n; |
| 2123 } else { | |
| 2124 msg = "unhandled input to ConvI2L"; | |
| 2125 } | |
| 2126 } else if (n == head->phi()) { | |
| 2127 // no shift, check below for allowed cases | |
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2128 found_index = true; |
| 1763 | 2129 } else { |
| 2130 msg = "unhandled node in address"; | |
| 2131 msg_node = n; | |
| 2132 } | |
| 2133 } | |
| 2134 | |
| 2135 if (count == -1) { | |
| 2136 msg = "malformed address expression"; | |
| 2137 msg_node = store; | |
| 2138 } | |
| 2139 | |
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2140 if (!found_index) { |
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2141 msg = "missing use of index"; |
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2142 } |
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2143 |
| 1763 | 2144 // byte sized items won't have a shift |
| 2145 if (msg == NULL && shift == NULL && t != T_BYTE && t != T_BOOLEAN) { | |
| 2146 msg = "can't find shift"; | |
| 2147 msg_node = store; | |
| 2148 } | |
| 2149 | |
| 2150 if (msg != NULL) { | |
| 2151 #ifndef PRODUCT | |
| 2152 if (TraceOptimizeFill) { | |
| 2153 tty->print_cr("not fill intrinsic: %s", msg); | |
| 2154 if (msg_node != NULL) msg_node->dump(); | |
| 2155 } | |
| 2156 #endif | |
| 2157 return false; | |
| 2158 } | |
| 2159 | |
| 2160 // No make sure all the other nodes in the loop can be handled | |
| 2161 VectorSet ok(Thread::current()->resource_area()); | |
| 2162 | |
| 2163 // store related values are ok | |
| 2164 ok.set(store->_idx); | |
| 2165 ok.set(store->in(MemNode::Memory)->_idx); | |
| 2166 | |
| 2167 // Loop structure is ok | |
| 2168 ok.set(head->_idx); | |
| 2169 ok.set(head->loopexit()->_idx); | |
| 2170 ok.set(head->phi()->_idx); | |
| 2171 ok.set(head->incr()->_idx); | |
| 2172 ok.set(head->loopexit()->cmp_node()->_idx); | |
| 2173 ok.set(head->loopexit()->in(1)->_idx); | |
| 2174 | |
| 2175 // Address elements are ok | |
| 2176 if (con) ok.set(con->_idx); | |
| 2177 if (shift) ok.set(shift->_idx); | |
| 2178 if (conv) ok.set(conv->_idx); | |
| 2179 | |
| 2180 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
| 2181 Node* n = lpt->_body.at(i); | |
| 2182 if (n->outcnt() == 0) continue; // Ignore dead | |
| 2183 if (ok.test(n->_idx)) continue; | |
| 2184 // Backedge projection is ok | |
| 2185 if (n->is_IfTrue() && n->in(0) == head->loopexit()) continue; | |
| 2186 if (!n->is_AddP()) { | |
| 2187 msg = "unhandled node"; | |
| 2188 msg_node = n; | |
| 2189 break; | |
| 2190 } | |
| 2191 } | |
| 2192 | |
| 2193 // Make sure no unexpected values are used outside the loop | |
| 2194 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
| 2195 Node* n = lpt->_body.at(i); | |
| 2196 // These values can be replaced with other nodes if they are used | |
| 2197 // outside the loop. | |
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2198 if (n == store || n == head->loopexit() || n == head->incr() || n == store->in(MemNode::Memory)) continue; |
| 1763 | 2199 for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) { |
| 2200 Node* use = iter.get(); | |
| 2201 if (!lpt->_body.contains(use)) { | |
| 2202 msg = "node is used outside loop"; | |
| 2203 // lpt->_body.dump(); | |
| 2204 msg_node = n; | |
| 2205 break; | |
| 2206 } | |
| 2207 } | |
| 2208 } | |
| 2209 | |
| 2210 #ifdef ASSERT | |
| 2211 if (TraceOptimizeFill) { | |
| 2212 if (msg != NULL) { | |
| 2213 tty->print_cr("no fill intrinsic: %s", msg); | |
| 2214 if (msg_node != NULL) msg_node->dump(); | |
| 2215 } else { | |
| 2216 tty->print_cr("fill intrinsic for:"); | |
| 2217 } | |
| 2218 store->dump(); | |
| 2219 if (Verbose) { | |
| 2220 lpt->_body.dump(); | |
| 2221 } | |
| 2222 } | |
| 2223 #endif | |
| 2224 | |
| 2225 return msg == NULL; | |
| 2226 } | |
| 2227 | |
| 2228 | |
| 2229 | |
| 2230 bool PhaseIdealLoop::intrinsify_fill(IdealLoopTree* lpt) { | |
| 2231 // Only for counted inner loops | |
| 2232 if (!lpt->is_counted() || !lpt->is_inner()) { | |
| 2233 return false; | |
| 2234 } | |
| 2235 | |
| 2236 // Must have constant stride | |
| 2237 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
| 2238 if (!head->stride_is_con() || !head->is_normal_loop()) { | |
| 2239 return false; | |
| 2240 } | |
| 2241 | |
| 2242 // Check that the body only contains a store of a loop invariant | |
| 2243 // value that is indexed by the loop phi. | |
| 2244 Node* store = NULL; | |
| 2245 Node* store_value = NULL; | |
| 2246 Node* shift = NULL; | |
| 2247 Node* offset = NULL; | |
| 2248 if (!match_fill_loop(lpt, store, store_value, shift, offset)) { | |
| 2249 return false; | |
| 2250 } | |
| 2251 | |
| 2445 | 2252 #ifndef PRODUCT |
| 2253 if (TraceLoopOpts) { | |
| 2254 tty->print("ArrayFill "); | |
| 2255 lpt->dump_head(); | |
| 2256 } | |
| 2257 #endif | |
| 2258 | |
| 1763 | 2259 // Now replace the whole loop body by a call to a fill routine that |
| 2260 // covers the same region as the loop. | |
| 2261 Node* base = store->in(MemNode::Address)->as_AddP()->in(AddPNode::Base); | |
| 2262 | |
| 2263 // Build an expression for the beginning of the copy region | |
| 2264 Node* index = head->init_trip(); | |
| 2265 #ifdef _LP64 | |
| 2266 index = new (C, 2) ConvI2LNode(index); | |
| 2267 _igvn.register_new_node_with_optimizer(index); | |
| 2268 #endif | |
| 2269 if (shift != NULL) { | |
| 2270 // byte arrays don't require a shift but others do. | |
| 2271 index = new (C, 3) LShiftXNode(index, shift->in(2)); | |
| 2272 _igvn.register_new_node_with_optimizer(index); | |
| 2273 } | |
| 2274 index = new (C, 4) AddPNode(base, base, index); | |
| 2275 _igvn.register_new_node_with_optimizer(index); | |
| 2276 Node* from = new (C, 4) AddPNode(base, index, offset); | |
| 2277 _igvn.register_new_node_with_optimizer(from); | |
| 2278 // Compute the number of elements to copy | |
| 2279 Node* len = new (C, 3) SubINode(head->limit(), head->init_trip()); | |
| 2280 _igvn.register_new_node_with_optimizer(len); | |
| 2281 | |
| 2282 BasicType t = store->as_Mem()->memory_type(); | |
| 2283 bool aligned = false; | |
| 2284 if (offset != NULL && head->init_trip()->is_Con()) { | |
| 2285 int element_size = type2aelembytes(t); | |
| 2286 aligned = (offset->find_intptr_t_type()->get_con() + head->init_trip()->get_int() * element_size) % HeapWordSize == 0; | |
| 2287 } | |
| 2288 | |
| 2289 // Build a call to the fill routine | |
| 2290 const char* fill_name; | |
| 2291 address fill = StubRoutines::select_fill_function(t, aligned, fill_name); | |
| 2292 assert(fill != NULL, "what?"); | |
| 2293 | |
| 2294 // Convert float/double to int/long for fill routines | |
| 2295 if (t == T_FLOAT) { | |
| 2296 store_value = new (C, 2) MoveF2INode(store_value); | |
| 2297 _igvn.register_new_node_with_optimizer(store_value); | |
| 2298 } else if (t == T_DOUBLE) { | |
| 2299 store_value = new (C, 2) MoveD2LNode(store_value); | |
| 2300 _igvn.register_new_node_with_optimizer(store_value); | |
| 2301 } | |
| 2302 | |
| 2303 Node* mem_phi = store->in(MemNode::Memory); | |
| 2304 Node* result_ctrl; | |
| 2305 Node* result_mem; | |
| 2306 const TypeFunc* call_type = OptoRuntime::array_fill_Type(); | |
| 2307 int size = call_type->domain()->cnt(); | |
| 2308 CallLeafNode *call = new (C, size) CallLeafNoFPNode(call_type, fill, | |
| 2309 fill_name, TypeAryPtr::get_array_body_type(t)); | |
| 2310 call->init_req(TypeFunc::Parms+0, from); | |
| 2311 call->init_req(TypeFunc::Parms+1, store_value); | |
|
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2312 #ifdef _LP64 |
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2313 len = new (C, 2) ConvI2LNode(len); |
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2314 _igvn.register_new_node_with_optimizer(len); |
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2315 #endif |
| 1763 | 2316 call->init_req(TypeFunc::Parms+2, len); |
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2317 #ifdef _LP64 |
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2318 call->init_req(TypeFunc::Parms+3, C->top()); |
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2319 #endif |
| 1763 | 2320 call->init_req( TypeFunc::Control, head->init_control()); |
| 2321 call->init_req( TypeFunc::I_O , C->top() ) ; // does no i/o | |
| 2322 call->init_req( TypeFunc::Memory , mem_phi->in(LoopNode::EntryControl) ); | |
| 2323 call->init_req( TypeFunc::ReturnAdr, C->start()->proj_out(TypeFunc::ReturnAdr) ); | |
| 2324 call->init_req( TypeFunc::FramePtr, C->start()->proj_out(TypeFunc::FramePtr) ); | |
| 2325 _igvn.register_new_node_with_optimizer(call); | |
| 2326 result_ctrl = new (C, 1) ProjNode(call,TypeFunc::Control); | |
| 2327 _igvn.register_new_node_with_optimizer(result_ctrl); | |
| 2328 result_mem = new (C, 1) ProjNode(call,TypeFunc::Memory); | |
| 2329 _igvn.register_new_node_with_optimizer(result_mem); | |
| 2330 | |
| 2331 // If this fill is tightly coupled to an allocation and overwrites | |
| 2332 // the whole body, allow it to take over the zeroing. | |
| 2333 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, this); | |
| 2334 if (alloc != NULL && alloc->is_AllocateArray()) { | |
| 2335 Node* length = alloc->as_AllocateArray()->Ideal_length(); | |
| 2336 if (head->limit() == length && | |
| 2337 head->init_trip() == _igvn.intcon(0)) { | |
| 2338 if (TraceOptimizeFill) { | |
| 2339 tty->print_cr("Eliminated zeroing in allocation"); | |
| 2340 } | |
| 2341 alloc->maybe_set_complete(&_igvn); | |
| 2342 } else { | |
| 2343 #ifdef ASSERT | |
| 2344 if (TraceOptimizeFill) { | |
| 2345 tty->print_cr("filling array but bounds don't match"); | |
| 2346 alloc->dump(); | |
| 2347 head->init_trip()->dump(); | |
| 2348 head->limit()->dump(); | |
| 2349 length->dump(); | |
| 2350 } | |
| 2351 #endif | |
| 2352 } | |
| 2353 } | |
| 2354 | |
| 2355 // Redirect the old control and memory edges that are outside the loop. | |
| 2356 Node* exit = head->loopexit()->proj_out(0); | |
|
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2357 // Sometimes the memory phi of the head is used as the outgoing |
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2358 // state of the loop. It's safe in this case to replace it with the |
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2359 // result_mem. |
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2360 _igvn.replace_node(store->in(MemNode::Memory), result_mem); |
| 1763 | 2361 _igvn.replace_node(exit, result_ctrl); |
| 2362 _igvn.replace_node(store, result_mem); | |
| 2363 // Any uses the increment outside of the loop become the loop limit. | |
| 2364 _igvn.replace_node(head->incr(), head->limit()); | |
| 2365 | |
| 2366 // Disconnect the head from the loop. | |
| 2367 for (uint i = 0; i < lpt->_body.size(); i++) { | |
| 2368 Node* n = lpt->_body.at(i); | |
| 2369 _igvn.replace_node(n, C->top()); | |
| 2370 } | |
| 2371 | |
| 2372 return true; | |
| 2373 } |