Mercurial > hg > truffle
annotate src/share/vm/opto/loopTransform.cpp @ 1303:c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
Reviewed-by: kvn
| author | never |
|---|---|
| date | Wed, 17 Mar 2010 16:40:25 -0700 |
| parents | 336c6c200f5f |
| children | c18cbe5936b8 |
| rev | line source |
|---|---|
| 0 | 1 /* |
|
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2 * Copyright 2000-2010 Sun Microsystems, Inc. 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 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_loopTransform.cpp.incl" | |
| 27 | |
| 28 //------------------------------is_loop_exit----------------------------------- | |
| 29 // Given an IfNode, return the loop-exiting projection or NULL if both | |
| 30 // arms remain in the loop. | |
| 31 Node *IdealLoopTree::is_loop_exit(Node *iff) const { | |
| 32 if( iff->outcnt() != 2 ) return NULL; // Ignore partially dead tests | |
| 33 PhaseIdealLoop *phase = _phase; | |
| 34 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
| 35 // we need loop unswitching instead of peeling. | |
| 36 if( !is_member(phase->get_loop( iff->raw_out(0) )) ) | |
| 37 return iff->raw_out(0); | |
| 38 if( !is_member(phase->get_loop( iff->raw_out(1) )) ) | |
| 39 return iff->raw_out(1); | |
| 40 return NULL; | |
| 41 } | |
| 42 | |
| 43 | |
| 44 //============================================================================= | |
| 45 | |
| 46 | |
| 47 //------------------------------record_for_igvn---------------------------- | |
| 48 // Put loop body on igvn work list | |
| 49 void IdealLoopTree::record_for_igvn() { | |
| 50 for( uint i = 0; i < _body.size(); i++ ) { | |
| 51 Node *n = _body.at(i); | |
| 52 _phase->_igvn._worklist.push(n); | |
| 53 } | |
| 54 } | |
| 55 | |
| 56 //------------------------------compute_profile_trip_cnt---------------------------- | |
| 57 // Compute loop trip count from profile data as | |
| 58 // (backedge_count + loop_exit_count) / loop_exit_count | |
| 59 void IdealLoopTree::compute_profile_trip_cnt( PhaseIdealLoop *phase ) { | |
| 60 if (!_head->is_CountedLoop()) { | |
| 61 return; | |
| 62 } | |
| 63 CountedLoopNode* head = _head->as_CountedLoop(); | |
| 64 if (head->profile_trip_cnt() != COUNT_UNKNOWN) { | |
| 65 return; // Already computed | |
| 66 } | |
| 67 float trip_cnt = (float)max_jint; // default is big | |
| 68 | |
| 69 Node* back = head->in(LoopNode::LoopBackControl); | |
| 70 while (back != head) { | |
| 71 if ((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && | |
| 72 back->in(0) && | |
| 73 back->in(0)->is_If() && | |
| 74 back->in(0)->as_If()->_fcnt != COUNT_UNKNOWN && | |
| 75 back->in(0)->as_If()->_prob != PROB_UNKNOWN) { | |
| 76 break; | |
| 77 } | |
| 78 back = phase->idom(back); | |
| 79 } | |
| 80 if (back != head) { | |
| 81 assert((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && | |
| 82 back->in(0), "if-projection exists"); | |
| 83 IfNode* back_if = back->in(0)->as_If(); | |
| 84 float loop_back_cnt = back_if->_fcnt * back_if->_prob; | |
| 85 | |
| 86 // Now compute a loop exit count | |
| 87 float loop_exit_cnt = 0.0f; | |
| 88 for( uint i = 0; i < _body.size(); i++ ) { | |
| 89 Node *n = _body[i]; | |
| 90 if( n->is_If() ) { | |
| 91 IfNode *iff = n->as_If(); | |
| 92 if( iff->_fcnt != COUNT_UNKNOWN && iff->_prob != PROB_UNKNOWN ) { | |
| 93 Node *exit = is_loop_exit(iff); | |
| 94 if( exit ) { | |
| 95 float exit_prob = iff->_prob; | |
| 96 if (exit->Opcode() == Op_IfFalse) exit_prob = 1.0 - exit_prob; | |
| 97 if (exit_prob > PROB_MIN) { | |
| 98 float exit_cnt = iff->_fcnt * exit_prob; | |
| 99 loop_exit_cnt += exit_cnt; | |
| 100 } | |
| 101 } | |
| 102 } | |
| 103 } | |
| 104 } | |
| 105 if (loop_exit_cnt > 0.0f) { | |
| 106 trip_cnt = (loop_back_cnt + loop_exit_cnt) / loop_exit_cnt; | |
| 107 } else { | |
| 108 // No exit count so use | |
| 109 trip_cnt = loop_back_cnt; | |
| 110 } | |
| 111 } | |
| 112 #ifndef PRODUCT | |
| 113 if (TraceProfileTripCount) { | |
| 114 tty->print_cr("compute_profile_trip_cnt lp: %d cnt: %f\n", head->_idx, trip_cnt); | |
| 115 } | |
| 116 #endif | |
| 117 head->set_profile_trip_cnt(trip_cnt); | |
| 118 } | |
| 119 | |
| 120 //---------------------is_invariant_addition----------------------------- | |
| 121 // Return nonzero index of invariant operand for an Add or Sub | |
| 605 | 122 // of (nonconstant) invariant and variant values. Helper for reassociate_invariants. |
| 0 | 123 int IdealLoopTree::is_invariant_addition(Node* n, PhaseIdealLoop *phase) { |
| 124 int op = n->Opcode(); | |
| 125 if (op == Op_AddI || op == Op_SubI) { | |
| 126 bool in1_invar = this->is_invariant(n->in(1)); | |
| 127 bool in2_invar = this->is_invariant(n->in(2)); | |
| 128 if (in1_invar && !in2_invar) return 1; | |
| 129 if (!in1_invar && in2_invar) return 2; | |
| 130 } | |
| 131 return 0; | |
| 132 } | |
| 133 | |
| 134 //---------------------reassociate_add_sub----------------------------- | |
| 135 // Reassociate invariant add and subtract expressions: | |
| 136 // | |
| 137 // inv1 + (x + inv2) => ( inv1 + inv2) + x | |
| 138 // (x + inv2) + inv1 => ( inv1 + inv2) + x | |
| 139 // inv1 + (x - inv2) => ( inv1 - inv2) + x | |
| 140 // inv1 - (inv2 - x) => ( inv1 - inv2) + x | |
| 141 // (x + inv2) - inv1 => (-inv1 + inv2) + x | |
| 142 // (x - inv2) + inv1 => ( inv1 - inv2) + x | |
| 143 // (x - inv2) - inv1 => (-inv1 - inv2) + x | |
| 144 // inv1 + (inv2 - x) => ( inv1 + inv2) - x | |
| 145 // inv1 - (x - inv2) => ( inv1 + inv2) - x | |
| 146 // (inv2 - x) + inv1 => ( inv1 + inv2) - x | |
| 147 // (inv2 - x) - inv1 => (-inv1 + inv2) - x | |
| 148 // inv1 - (x + inv2) => ( inv1 - inv2) - x | |
| 149 // | |
| 150 Node* IdealLoopTree::reassociate_add_sub(Node* n1, PhaseIdealLoop *phase) { | |
| 151 if (!n1->is_Add() && !n1->is_Sub() || n1->outcnt() == 0) return NULL; | |
| 152 if (is_invariant(n1)) return NULL; | |
| 153 int inv1_idx = is_invariant_addition(n1, phase); | |
| 154 if (!inv1_idx) return NULL; | |
| 155 // Don't mess with add of constant (igvn moves them to expression tree root.) | |
| 156 if (n1->is_Add() && n1->in(2)->is_Con()) return NULL; | |
| 157 Node* inv1 = n1->in(inv1_idx); | |
| 158 Node* n2 = n1->in(3 - inv1_idx); | |
| 159 int inv2_idx = is_invariant_addition(n2, phase); | |
| 160 if (!inv2_idx) return NULL; | |
| 161 Node* x = n2->in(3 - inv2_idx); | |
| 162 Node* inv2 = n2->in(inv2_idx); | |
| 163 | |
| 164 bool neg_x = n2->is_Sub() && inv2_idx == 1; | |
| 165 bool neg_inv2 = n2->is_Sub() && inv2_idx == 2; | |
| 166 bool neg_inv1 = n1->is_Sub() && inv1_idx == 2; | |
| 167 if (n1->is_Sub() && inv1_idx == 1) { | |
| 168 neg_x = !neg_x; | |
| 169 neg_inv2 = !neg_inv2; | |
| 170 } | |
| 171 Node* inv1_c = phase->get_ctrl(inv1); | |
| 172 Node* inv2_c = phase->get_ctrl(inv2); | |
| 173 Node* n_inv1; | |
| 174 if (neg_inv1) { | |
| 175 Node *zero = phase->_igvn.intcon(0); | |
| 176 phase->set_ctrl(zero, phase->C->root()); | |
| 177 n_inv1 = new (phase->C, 3) SubINode(zero, inv1); | |
| 178 phase->register_new_node(n_inv1, inv1_c); | |
| 179 } else { | |
| 180 n_inv1 = inv1; | |
| 181 } | |
| 182 Node* inv; | |
| 183 if (neg_inv2) { | |
| 184 inv = new (phase->C, 3) SubINode(n_inv1, inv2); | |
| 185 } else { | |
| 186 inv = new (phase->C, 3) AddINode(n_inv1, inv2); | |
| 187 } | |
| 188 phase->register_new_node(inv, phase->get_early_ctrl(inv)); | |
| 189 | |
| 190 Node* addx; | |
| 191 if (neg_x) { | |
| 192 addx = new (phase->C, 3) SubINode(inv, x); | |
| 193 } else { | |
| 194 addx = new (phase->C, 3) AddINode(x, inv); | |
| 195 } | |
| 196 phase->register_new_node(addx, phase->get_ctrl(x)); | |
| 197 phase->_igvn.hash_delete(n1); | |
| 198 phase->_igvn.subsume_node(n1, addx); | |
| 199 return addx; | |
| 200 } | |
| 201 | |
| 202 //---------------------reassociate_invariants----------------------------- | |
| 203 // Reassociate invariant expressions: | |
| 204 void IdealLoopTree::reassociate_invariants(PhaseIdealLoop *phase) { | |
| 205 for (int i = _body.size() - 1; i >= 0; i--) { | |
| 206 Node *n = _body.at(i); | |
| 207 for (int j = 0; j < 5; j++) { | |
| 208 Node* nn = reassociate_add_sub(n, phase); | |
| 209 if (nn == NULL) break; | |
| 210 n = nn; // again | |
| 211 }; | |
| 212 } | |
| 213 } | |
| 214 | |
| 215 //------------------------------policy_peeling--------------------------------- | |
| 216 // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can | |
| 217 // make some loop-invariant test (usually a null-check) happen before the loop. | |
| 218 bool IdealLoopTree::policy_peeling( PhaseIdealLoop *phase ) const { | |
| 219 Node *test = ((IdealLoopTree*)this)->tail(); | |
| 220 int body_size = ((IdealLoopTree*)this)->_body.size(); | |
| 221 int uniq = phase->C->unique(); | |
| 222 // Peeling does loop cloning which can result in O(N^2) node construction | |
| 223 if( body_size > 255 /* Prevent overflow for large body_size */ | |
| 224 || (body_size * body_size + uniq > MaxNodeLimit) ) { | |
| 225 return false; // too large to safely clone | |
| 226 } | |
| 227 while( test != _head ) { // Scan till run off top of loop | |
| 228 if( test->is_If() ) { // Test? | |
| 229 Node *ctrl = phase->get_ctrl(test->in(1)); | |
| 230 if (ctrl->is_top()) | |
| 231 return false; // Found dead test on live IF? No peeling! | |
| 232 // Standard IF only has one input value to check for loop invariance | |
| 233 assert( test->Opcode() == Op_If || test->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
| 234 // Condition is not a member of this loop? | |
| 235 if( !is_member(phase->get_loop(ctrl)) && | |
| 236 is_loop_exit(test) ) | |
| 237 return true; // Found reason to peel! | |
| 238 } | |
| 239 // Walk up dominators to loop _head looking for test which is | |
| 240 // executed on every path thru loop. | |
| 241 test = phase->idom(test); | |
| 242 } | |
| 243 return false; | |
| 244 } | |
| 245 | |
| 246 //------------------------------peeled_dom_test_elim--------------------------- | |
| 247 // If we got the effect of peeling, either by actually peeling or by making | |
| 248 // a pre-loop which must execute at least once, we can remove all | |
| 249 // loop-invariant dominated tests in the main body. | |
| 250 void PhaseIdealLoop::peeled_dom_test_elim( IdealLoopTree *loop, Node_List &old_new ) { | |
| 251 bool progress = true; | |
| 252 while( progress ) { | |
| 253 progress = false; // Reset for next iteration | |
| 254 Node *prev = loop->_head->in(LoopNode::LoopBackControl);//loop->tail(); | |
| 255 Node *test = prev->in(0); | |
| 256 while( test != loop->_head ) { // Scan till run off top of loop | |
| 257 | |
| 258 int p_op = prev->Opcode(); | |
| 259 if( (p_op == Op_IfFalse || p_op == Op_IfTrue) && | |
| 260 test->is_If() && // Test? | |
| 261 !test->in(1)->is_Con() && // And not already obvious? | |
| 262 // Condition is not a member of this loop? | |
| 263 !loop->is_member(get_loop(get_ctrl(test->in(1))))){ | |
| 264 // Walk loop body looking for instances of this test | |
| 265 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
| 266 Node *n = loop->_body.at(i); | |
| 267 if( n->is_If() && n->in(1) == test->in(1) /*&& n != loop->tail()->in(0)*/ ) { | |
| 268 // IfNode was dominated by version in peeled loop body | |
| 269 progress = true; | |
| 270 dominated_by( old_new[prev->_idx], n ); | |
| 271 } | |
| 272 } | |
| 273 } | |
| 274 prev = test; | |
| 275 test = idom(test); | |
| 276 } // End of scan tests in loop | |
| 277 | |
| 278 } // End of while( progress ) | |
| 279 } | |
| 280 | |
| 281 //------------------------------do_peeling------------------------------------- | |
| 282 // Peel the first iteration of the given loop. | |
| 283 // Step 1: Clone the loop body. The clone becomes the peeled iteration. | |
| 284 // The pre-loop illegally has 2 control users (old & new loops). | |
| 285 // Step 2: Make the old-loop fall-in edges point to the peeled iteration. | |
| 286 // Do this by making the old-loop fall-in edges act as if they came | |
| 287 // around the loopback from the prior iteration (follow the old-loop | |
| 288 // backedges) and then map to the new peeled iteration. This leaves | |
| 289 // the pre-loop with only 1 user (the new peeled iteration), but the | |
| 290 // peeled-loop backedge has 2 users. | |
| 291 // Step 3: Cut the backedge on the clone (so its not a loop) and remove the | |
| 292 // extra backedge user. | |
| 293 void PhaseIdealLoop::do_peeling( IdealLoopTree *loop, Node_List &old_new ) { | |
| 294 | |
| 295 C->set_major_progress(); | |
| 296 // Peeling a 'main' loop in a pre/main/post situation obfuscates the | |
| 297 // 'pre' loop from the main and the 'pre' can no longer have it's | |
| 298 // iterations adjusted. Therefore, we need to declare this loop as | |
| 299 // no longer a 'main' loop; it will need new pre and post loops before | |
| 300 // we can do further RCE. | |
| 301 Node *h = loop->_head; | |
| 302 if( h->is_CountedLoop() ) { | |
| 303 CountedLoopNode *cl = h->as_CountedLoop(); | |
| 304 assert(cl->trip_count() > 0, "peeling a fully unrolled loop"); | |
| 305 cl->set_trip_count(cl->trip_count() - 1); | |
| 306 if( cl->is_main_loop() ) { | |
| 307 cl->set_normal_loop(); | |
| 308 #ifndef PRODUCT | |
| 309 if( PrintOpto && VerifyLoopOptimizations ) { | |
| 310 tty->print("Peeling a 'main' loop; resetting to 'normal' "); | |
| 311 loop->dump_head(); | |
| 312 } | |
| 313 #endif | |
| 314 } | |
| 315 } | |
| 316 | |
| 317 // Step 1: Clone the loop body. The clone becomes the peeled iteration. | |
| 318 // The pre-loop illegally has 2 control users (old & new loops). | |
| 319 clone_loop( loop, old_new, dom_depth(loop->_head) ); | |
| 320 | |
| 321 | |
| 322 // Step 2: Make the old-loop fall-in edges point to the peeled iteration. | |
| 323 // Do this by making the old-loop fall-in edges act as if they came | |
| 324 // around the loopback from the prior iteration (follow the old-loop | |
| 325 // backedges) and then map to the new peeled iteration. This leaves | |
| 326 // the pre-loop with only 1 user (the new peeled iteration), but the | |
| 327 // peeled-loop backedge has 2 users. | |
| 328 for (DUIterator_Fast jmax, j = loop->_head->fast_outs(jmax); j < jmax; j++) { | |
| 329 Node* old = loop->_head->fast_out(j); | |
| 330 if( old->in(0) == loop->_head && old->req() == 3 && | |
| 331 (old->is_Loop() || old->is_Phi()) ) { | |
| 332 Node *new_exit_value = old_new[old->in(LoopNode::LoopBackControl)->_idx]; | |
| 333 if( !new_exit_value ) // Backedge value is ALSO loop invariant? | |
| 334 // Then loop body backedge value remains the same. | |
| 335 new_exit_value = old->in(LoopNode::LoopBackControl); | |
| 336 _igvn.hash_delete(old); | |
| 337 old->set_req(LoopNode::EntryControl, new_exit_value); | |
| 338 } | |
| 339 } | |
| 340 | |
| 341 | |
| 342 // Step 3: Cut the backedge on the clone (so its not a loop) and remove the | |
| 343 // extra backedge user. | |
| 344 Node *nnn = old_new[loop->_head->_idx]; | |
| 345 _igvn.hash_delete(nnn); | |
| 346 nnn->set_req(LoopNode::LoopBackControl, C->top()); | |
| 347 for (DUIterator_Fast j2max, j2 = nnn->fast_outs(j2max); j2 < j2max; j2++) { | |
| 348 Node* use = nnn->fast_out(j2); | |
| 349 if( use->in(0) == nnn && use->req() == 3 && use->is_Phi() ) { | |
| 350 _igvn.hash_delete(use); | |
| 351 use->set_req(LoopNode::LoopBackControl, C->top()); | |
| 352 } | |
| 353 } | |
| 354 | |
| 355 | |
| 356 // Step 4: Correct dom-depth info. Set to loop-head depth. | |
| 357 int dd = dom_depth(loop->_head); | |
| 358 set_idom(loop->_head, loop->_head->in(1), dd); | |
| 359 for (uint j3 = 0; j3 < loop->_body.size(); j3++) { | |
| 360 Node *old = loop->_body.at(j3); | |
| 361 Node *nnn = old_new[old->_idx]; | |
| 362 if (!has_ctrl(nnn)) | |
| 363 set_idom(nnn, idom(nnn), dd-1); | |
| 364 // While we're at it, remove any SafePoints from the peeled code | |
| 365 if( old->Opcode() == Op_SafePoint ) { | |
| 366 Node *nnn = old_new[old->_idx]; | |
| 367 lazy_replace(nnn,nnn->in(TypeFunc::Control)); | |
| 368 } | |
| 369 } | |
| 370 | |
| 371 // Now force out all loop-invariant dominating tests. The optimizer | |
| 372 // finds some, but we _know_ they are all useless. | |
| 373 peeled_dom_test_elim(loop,old_new); | |
| 374 | |
| 375 loop->record_for_igvn(); | |
| 376 } | |
| 377 | |
| 378 //------------------------------policy_maximally_unroll------------------------ | |
| 379 // Return exact loop trip count, or 0 if not maximally unrolling | |
| 380 bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const { | |
| 381 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 382 assert( cl->is_normal_loop(), "" ); | |
| 383 | |
| 384 Node *init_n = cl->init_trip(); | |
| 385 Node *limit_n = cl->limit(); | |
| 386 | |
| 387 // Non-constant bounds | |
| 388 if( init_n == NULL || !init_n->is_Con() || | |
| 389 limit_n == NULL || !limit_n->is_Con() || | |
| 390 // protect against stride not being a constant | |
| 391 !cl->stride_is_con() ) { | |
| 392 return false; | |
| 393 } | |
| 394 int init = init_n->get_int(); | |
| 395 int limit = limit_n->get_int(); | |
| 396 int span = limit - init; | |
| 397 int stride = cl->stride_con(); | |
| 398 | |
| 399 if (init >= limit || stride > span) { | |
| 400 // return a false (no maximally unroll) and the regular unroll/peel | |
| 401 // route will make a small mess which CCP will fold away. | |
| 402 return false; | |
| 403 } | |
| 404 uint trip_count = span/stride; // trip_count can be greater than 2 Gig. | |
| 405 assert( (int)trip_count*stride == span, "must divide evenly" ); | |
| 406 | |
| 407 // Real policy: if we maximally unroll, does it get too big? | |
| 408 // Allow the unrolled mess to get larger than standard loop | |
| 409 // size. After all, it will no longer be a loop. | |
| 410 uint body_size = _body.size(); | |
| 411 uint unroll_limit = (uint)LoopUnrollLimit * 4; | |
| 412 assert( (intx)unroll_limit == LoopUnrollLimit * 4, "LoopUnrollLimit must fit in 32bits"); | |
| 413 cl->set_trip_count(trip_count); | |
| 414 if( trip_count <= unroll_limit && body_size <= unroll_limit ) { | |
| 415 uint new_body_size = body_size * trip_count; | |
| 416 if (new_body_size <= unroll_limit && | |
| 417 body_size == new_body_size / trip_count && | |
| 418 // Unrolling can result in a large amount of node construction | |
| 419 new_body_size < MaxNodeLimit - phase->C->unique()) { | |
| 420 return true; // maximally unroll | |
| 421 } | |
| 422 } | |
| 423 | |
| 424 return false; // Do not maximally unroll | |
| 425 } | |
| 426 | |
| 427 | |
| 428 //------------------------------policy_unroll---------------------------------- | |
| 429 // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if | |
| 430 // the loop is a CountedLoop and the body is small enough. | |
| 431 bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const { | |
| 432 | |
| 433 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 434 assert( cl->is_normal_loop() || cl->is_main_loop(), "" ); | |
| 435 | |
| 436 // protect against stride not being a constant | |
| 437 if( !cl->stride_is_con() ) return false; | |
| 438 | |
| 439 // protect against over-unrolling | |
| 440 if( cl->trip_count() <= 1 ) return false; | |
| 441 | |
| 442 int future_unroll_ct = cl->unrolled_count() * 2; | |
| 443 | |
| 444 // Don't unroll if the next round of unrolling would push us | |
| 445 // over the expected trip count of the loop. One is subtracted | |
| 446 // from the expected trip count because the pre-loop normally | |
| 447 // executes 1 iteration. | |
| 448 if (UnrollLimitForProfileCheck > 0 && | |
| 449 cl->profile_trip_cnt() != COUNT_UNKNOWN && | |
| 450 future_unroll_ct > UnrollLimitForProfileCheck && | |
| 451 (float)future_unroll_ct > cl->profile_trip_cnt() - 1.0) { | |
| 452 return false; | |
| 453 } | |
| 454 | |
| 455 // When unroll count is greater than LoopUnrollMin, don't unroll if: | |
| 456 // the residual iterations are more than 10% of the trip count | |
| 457 // and rounds of "unroll,optimize" are not making significant progress | |
| 458 // Progress defined as current size less than 20% larger than previous size. | |
| 459 if (UseSuperWord && cl->node_count_before_unroll() > 0 && | |
| 460 future_unroll_ct > LoopUnrollMin && | |
| 461 (future_unroll_ct - 1) * 10.0 > cl->profile_trip_cnt() && | |
| 462 1.2 * cl->node_count_before_unroll() < (double)_body.size()) { | |
| 463 return false; | |
| 464 } | |
| 465 | |
| 466 Node *init_n = cl->init_trip(); | |
| 467 Node *limit_n = cl->limit(); | |
| 468 // Non-constant bounds. | |
| 469 // Protect against over-unrolling when init or/and limit are not constant | |
| 470 // (so that trip_count's init value is maxint) but iv range is known. | |
| 471 if( init_n == NULL || !init_n->is_Con() || | |
| 472 limit_n == NULL || !limit_n->is_Con() ) { | |
| 473 Node* phi = cl->phi(); | |
| 474 if( phi != NULL ) { | |
| 475 assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi."); | |
| 476 const TypeInt* iv_type = phase->_igvn.type(phi)->is_int(); | |
| 477 int next_stride = cl->stride_con() * 2; // stride after this unroll | |
| 478 if( next_stride > 0 ) { | |
| 479 if( iv_type->_lo + next_stride <= iv_type->_lo || // overflow | |
| 480 iv_type->_lo + next_stride > iv_type->_hi ) { | |
| 481 return false; // over-unrolling | |
| 482 } | |
| 483 } else if( next_stride < 0 ) { | |
| 484 if( iv_type->_hi + next_stride >= iv_type->_hi || // overflow | |
| 485 iv_type->_hi + next_stride < iv_type->_lo ) { | |
| 486 return false; // over-unrolling | |
| 487 } | |
| 488 } | |
| 489 } | |
| 490 } | |
| 491 | |
| 492 // Adjust body_size to determine if we unroll or not | |
| 493 uint body_size = _body.size(); | |
| 494 // Key test to unroll CaffeineMark's Logic test | |
| 495 int xors_in_loop = 0; | |
| 496 // Also count ModL, DivL and MulL which expand mightly | |
| 497 for( uint k = 0; k < _body.size(); k++ ) { | |
| 498 switch( _body.at(k)->Opcode() ) { | |
| 499 case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test | |
| 500 case Op_ModL: body_size += 30; break; | |
| 501 case Op_DivL: body_size += 30; break; | |
| 502 case Op_MulL: body_size += 10; break; | |
| 503 } | |
| 504 } | |
| 505 | |
| 506 // Check for being too big | |
| 507 if( body_size > (uint)LoopUnrollLimit ) { | |
| 508 if( xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true; | |
| 509 // Normal case: loop too big | |
| 510 return false; | |
| 511 } | |
| 512 | |
| 513 // Check for stride being a small enough constant | |
| 514 if( abs(cl->stride_con()) > (1<<3) ) return false; | |
| 515 | |
| 516 // Unroll once! (Each trip will soon do double iterations) | |
| 517 return true; | |
| 518 } | |
| 519 | |
| 520 //------------------------------policy_align----------------------------------- | |
| 521 // Return TRUE or FALSE if the loop should be cache-line aligned. Gather the | |
| 522 // expression that does the alignment. Note that only one array base can be | |
| 605 | 523 // aligned in a loop (unless the VM guarantees mutual alignment). Note that |
| 0 | 524 // if we vectorize short memory ops into longer memory ops, we may want to |
| 525 // increase alignment. | |
| 526 bool IdealLoopTree::policy_align( PhaseIdealLoop *phase ) const { | |
| 527 return false; | |
| 528 } | |
| 529 | |
| 530 //------------------------------policy_range_check----------------------------- | |
| 531 // Return TRUE or FALSE if the loop should be range-check-eliminated. | |
| 532 // Actually we do iteration-splitting, a more powerful form of RCE. | |
| 533 bool IdealLoopTree::policy_range_check( PhaseIdealLoop *phase ) const { | |
| 534 if( !RangeCheckElimination ) return false; | |
| 535 | |
| 536 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 537 // If we unrolled with no intention of doing RCE and we later | |
| 538 // changed our minds, we got no pre-loop. Either we need to | |
| 539 // make a new pre-loop, or we gotta disallow RCE. | |
| 540 if( cl->is_main_no_pre_loop() ) return false; // Disallowed for now. | |
| 541 Node *trip_counter = cl->phi(); | |
| 542 | |
| 543 // Check loop body for tests of trip-counter plus loop-invariant vs | |
| 544 // loop-invariant. | |
| 545 for( uint i = 0; i < _body.size(); i++ ) { | |
| 546 Node *iff = _body[i]; | |
| 547 if( iff->Opcode() == Op_If ) { // Test? | |
| 548 | |
| 549 // Comparing trip+off vs limit | |
| 550 Node *bol = iff->in(1); | |
| 551 if( bol->req() != 2 ) continue; // dead constant test | |
| 1172 | 552 if (!bol->is_Bool()) { |
| 553 assert(UseLoopPredicate && bol->Opcode() == Op_Conv2B, "predicate check only"); | |
| 554 continue; | |
| 555 } | |
| 0 | 556 Node *cmp = bol->in(1); |
| 557 | |
| 558 Node *rc_exp = cmp->in(1); | |
| 559 Node *limit = cmp->in(2); | |
| 560 | |
| 561 Node *limit_c = phase->get_ctrl(limit); | |
| 562 if( limit_c == phase->C->top() ) | |
| 563 return false; // Found dead test on live IF? No RCE! | |
| 564 if( is_member(phase->get_loop(limit_c) ) ) { | |
| 565 // Compare might have operands swapped; commute them | |
| 566 rc_exp = cmp->in(2); | |
| 567 limit = cmp->in(1); | |
| 568 limit_c = phase->get_ctrl(limit); | |
| 569 if( is_member(phase->get_loop(limit_c) ) ) | |
| 570 continue; // Both inputs are loop varying; cannot RCE | |
| 571 } | |
| 572 | |
| 573 if (!phase->is_scaled_iv_plus_offset(rc_exp, trip_counter, NULL, NULL)) { | |
| 574 continue; | |
| 575 } | |
| 576 // Yeah! Found a test like 'trip+off vs limit' | |
| 577 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
| 578 // we need loop unswitching instead of iteration splitting. | |
| 579 if( is_loop_exit(iff) ) | |
| 580 return true; // Found reason to split iterations | |
| 581 } // End of is IF | |
| 582 } | |
| 583 | |
| 584 return false; | |
| 585 } | |
| 586 | |
| 587 //------------------------------policy_peel_only------------------------------- | |
| 588 // Return TRUE or FALSE if the loop should NEVER be RCE'd or aligned. Useful | |
| 589 // for unrolling loops with NO array accesses. | |
| 590 bool IdealLoopTree::policy_peel_only( PhaseIdealLoop *phase ) const { | |
| 591 | |
| 592 for( uint i = 0; i < _body.size(); i++ ) | |
| 593 if( _body[i]->is_Mem() ) | |
| 594 return false; | |
| 595 | |
| 596 // No memory accesses at all! | |
| 597 return true; | |
| 598 } | |
| 599 | |
| 600 //------------------------------clone_up_backedge_goo-------------------------- | |
| 601 // If Node n lives in the back_ctrl block and cannot float, we clone a private | |
| 602 // version of n in preheader_ctrl block and return that, otherwise return n. | |
| 603 Node *PhaseIdealLoop::clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n ) { | |
| 604 if( get_ctrl(n) != back_ctrl ) return n; | |
| 605 | |
| 606 Node *x = NULL; // If required, a clone of 'n' | |
| 607 // Check for 'n' being pinned in the backedge. | |
| 608 if( n->in(0) && n->in(0) == back_ctrl ) { | |
| 609 x = n->clone(); // Clone a copy of 'n' to preheader | |
| 610 x->set_req( 0, preheader_ctrl ); // Fix x's control input to preheader | |
| 611 } | |
| 612 | |
| 613 // Recursive fixup any other input edges into x. | |
| 614 // If there are no changes we can just return 'n', otherwise | |
| 615 // we need to clone a private copy and change it. | |
| 616 for( uint i = 1; i < n->req(); i++ ) { | |
| 617 Node *g = clone_up_backedge_goo( back_ctrl, preheader_ctrl, n->in(i) ); | |
| 618 if( g != n->in(i) ) { | |
| 619 if( !x ) | |
| 620 x = n->clone(); | |
| 621 x->set_req(i, g); | |
| 622 } | |
| 623 } | |
| 624 if( x ) { // x can legally float to pre-header location | |
| 625 register_new_node( x, preheader_ctrl ); | |
| 626 return x; | |
| 627 } else { // raise n to cover LCA of uses | |
| 628 set_ctrl( n, find_non_split_ctrl(back_ctrl->in(0)) ); | |
| 629 } | |
| 630 return n; | |
| 631 } | |
| 632 | |
| 633 //------------------------------insert_pre_post_loops-------------------------- | |
| 634 // Insert pre and post loops. If peel_only is set, the pre-loop can not have | |
| 635 // more iterations added. It acts as a 'peel' only, no lower-bound RCE, no | |
| 636 // alignment. Useful to unroll loops that do no array accesses. | |
| 637 void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ) { | |
| 638 | |
| 639 C->set_major_progress(); | |
| 640 | |
| 641 // Find common pieces of the loop being guarded with pre & post loops | |
| 642 CountedLoopNode *main_head = loop->_head->as_CountedLoop(); | |
| 643 assert( main_head->is_normal_loop(), "" ); | |
| 644 CountedLoopEndNode *main_end = main_head->loopexit(); | |
| 645 assert( main_end->outcnt() == 2, "1 true, 1 false path only" ); | |
| 646 uint dd_main_head = dom_depth(main_head); | |
| 647 uint max = main_head->outcnt(); | |
| 648 | |
| 649 Node *pre_header= main_head->in(LoopNode::EntryControl); | |
| 650 Node *init = main_head->init_trip(); | |
| 651 Node *incr = main_end ->incr(); | |
| 652 Node *limit = main_end ->limit(); | |
| 653 Node *stride = main_end ->stride(); | |
| 654 Node *cmp = main_end ->cmp_node(); | |
| 655 BoolTest::mask b_test = main_end->test_trip(); | |
| 656 | |
| 657 // Need only 1 user of 'bol' because I will be hacking the loop bounds. | |
| 658 Node *bol = main_end->in(CountedLoopEndNode::TestValue); | |
| 659 if( bol->outcnt() != 1 ) { | |
| 660 bol = bol->clone(); | |
| 661 register_new_node(bol,main_end->in(CountedLoopEndNode::TestControl)); | |
| 662 _igvn.hash_delete(main_end); | |
| 663 main_end->set_req(CountedLoopEndNode::TestValue, bol); | |
| 664 } | |
| 665 // Need only 1 user of 'cmp' because I will be hacking the loop bounds. | |
| 666 if( cmp->outcnt() != 1 ) { | |
| 667 cmp = cmp->clone(); | |
| 668 register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl)); | |
| 669 _igvn.hash_delete(bol); | |
| 670 bol->set_req(1, cmp); | |
| 671 } | |
| 672 | |
| 673 //------------------------------ | |
| 674 // Step A: Create Post-Loop. | |
| 675 Node* main_exit = main_end->proj_out(false); | |
| 676 assert( main_exit->Opcode() == Op_IfFalse, "" ); | |
| 677 int dd_main_exit = dom_depth(main_exit); | |
| 678 | |
| 679 // Step A1: Clone the loop body. The clone becomes the post-loop. The main | |
| 680 // loop pre-header illegally has 2 control users (old & new loops). | |
| 681 clone_loop( loop, old_new, dd_main_exit ); | |
| 682 assert( old_new[main_end ->_idx]->Opcode() == Op_CountedLoopEnd, "" ); | |
| 683 CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop(); | |
| 684 post_head->set_post_loop(main_head); | |
| 685 | |
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686 // Reduce the post-loop trip count. |
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687 CountedLoopEndNode* post_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
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688 post_end->_prob = PROB_FAIR; |
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689 |
| 0 | 690 // Build the main-loop normal exit. |
| 691 IfFalseNode *new_main_exit = new (C, 1) IfFalseNode(main_end); | |
| 692 _igvn.register_new_node_with_optimizer( new_main_exit ); | |
| 693 set_idom(new_main_exit, main_end, dd_main_exit ); | |
| 694 set_loop(new_main_exit, loop->_parent); | |
| 695 | |
| 696 // Step A2: Build a zero-trip guard for the post-loop. After leaving the | |
| 697 // main-loop, the post-loop may not execute at all. We 'opaque' the incr | |
| 698 // (the main-loop trip-counter exit value) because we will be changing | |
| 699 // the exit value (via unrolling) so we cannot constant-fold away the zero | |
| 700 // trip guard until all unrolling is done. | |
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701 Node *zer_opaq = new (C, 2) Opaque1Node(C, incr); |
| 0 | 702 Node *zer_cmp = new (C, 3) CmpINode( zer_opaq, limit ); |
| 703 Node *zer_bol = new (C, 2) BoolNode( zer_cmp, b_test ); | |
| 704 register_new_node( zer_opaq, new_main_exit ); | |
| 705 register_new_node( zer_cmp , new_main_exit ); | |
| 706 register_new_node( zer_bol , new_main_exit ); | |
| 707 | |
| 708 // Build the IfNode | |
| 709 IfNode *zer_iff = new (C, 2) IfNode( new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN ); | |
| 710 _igvn.register_new_node_with_optimizer( zer_iff ); | |
| 711 set_idom(zer_iff, new_main_exit, dd_main_exit); | |
| 712 set_loop(zer_iff, loop->_parent); | |
| 713 | |
| 714 // Plug in the false-path, taken if we need to skip post-loop | |
| 715 _igvn.hash_delete( main_exit ); | |
| 716 main_exit->set_req(0, zer_iff); | |
| 717 _igvn._worklist.push(main_exit); | |
| 718 set_idom(main_exit, zer_iff, dd_main_exit); | |
| 719 set_idom(main_exit->unique_out(), zer_iff, dd_main_exit); | |
| 720 // Make the true-path, must enter the post loop | |
| 721 Node *zer_taken = new (C, 1) IfTrueNode( zer_iff ); | |
| 722 _igvn.register_new_node_with_optimizer( zer_taken ); | |
| 723 set_idom(zer_taken, zer_iff, dd_main_exit); | |
| 724 set_loop(zer_taken, loop->_parent); | |
| 725 // Plug in the true path | |
| 726 _igvn.hash_delete( post_head ); | |
| 727 post_head->set_req(LoopNode::EntryControl, zer_taken); | |
| 728 set_idom(post_head, zer_taken, dd_main_exit); | |
| 729 | |
| 730 // Step A3: Make the fall-in values to the post-loop come from the | |
| 731 // fall-out values of the main-loop. | |
| 732 for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) { | |
| 733 Node* main_phi = main_head->fast_out(i); | |
| 734 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0 ) { | |
| 735 Node *post_phi = old_new[main_phi->_idx]; | |
| 736 Node *fallmain = clone_up_backedge_goo(main_head->back_control(), | |
| 737 post_head->init_control(), | |
| 738 main_phi->in(LoopNode::LoopBackControl)); | |
| 739 _igvn.hash_delete(post_phi); | |
| 740 post_phi->set_req( LoopNode::EntryControl, fallmain ); | |
| 741 } | |
| 742 } | |
| 743 | |
| 744 // Update local caches for next stanza | |
| 745 main_exit = new_main_exit; | |
| 746 | |
| 747 | |
| 748 //------------------------------ | |
| 749 // Step B: Create Pre-Loop. | |
| 750 | |
| 751 // Step B1: Clone the loop body. The clone becomes the pre-loop. The main | |
| 752 // loop pre-header illegally has 2 control users (old & new loops). | |
| 753 clone_loop( loop, old_new, dd_main_head ); | |
| 754 CountedLoopNode* pre_head = old_new[main_head->_idx]->as_CountedLoop(); | |
| 755 CountedLoopEndNode* pre_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); | |
| 756 pre_head->set_pre_loop(main_head); | |
| 757 Node *pre_incr = old_new[incr->_idx]; | |
| 758 | |
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759 // Reduce the pre-loop trip count. |
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760 pre_end->_prob = PROB_FAIR; |
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761 |
| 0 | 762 // Find the pre-loop normal exit. |
| 763 Node* pre_exit = pre_end->proj_out(false); | |
| 764 assert( pre_exit->Opcode() == Op_IfFalse, "" ); | |
| 765 IfFalseNode *new_pre_exit = new (C, 1) IfFalseNode(pre_end); | |
| 766 _igvn.register_new_node_with_optimizer( new_pre_exit ); | |
| 767 set_idom(new_pre_exit, pre_end, dd_main_head); | |
| 768 set_loop(new_pre_exit, loop->_parent); | |
| 769 | |
| 770 // Step B2: Build a zero-trip guard for the main-loop. After leaving the | |
| 771 // pre-loop, the main-loop may not execute at all. Later in life this | |
| 772 // zero-trip guard will become the minimum-trip guard when we unroll | |
| 773 // the main-loop. | |
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774 Node *min_opaq = new (C, 2) Opaque1Node(C, limit); |
| 0 | 775 Node *min_cmp = new (C, 3) CmpINode( pre_incr, min_opaq ); |
| 776 Node *min_bol = new (C, 2) BoolNode( min_cmp, b_test ); | |
| 777 register_new_node( min_opaq, new_pre_exit ); | |
| 778 register_new_node( min_cmp , new_pre_exit ); | |
| 779 register_new_node( min_bol , new_pre_exit ); | |
| 780 | |
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781 // Build the IfNode (assume the main-loop is executed always). |
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782 IfNode *min_iff = new (C, 2) IfNode( new_pre_exit, min_bol, PROB_ALWAYS, COUNT_UNKNOWN ); |
| 0 | 783 _igvn.register_new_node_with_optimizer( min_iff ); |
| 784 set_idom(min_iff, new_pre_exit, dd_main_head); | |
| 785 set_loop(min_iff, loop->_parent); | |
| 786 | |
| 787 // Plug in the false-path, taken if we need to skip main-loop | |
| 788 _igvn.hash_delete( pre_exit ); | |
| 789 pre_exit->set_req(0, min_iff); | |
| 790 set_idom(pre_exit, min_iff, dd_main_head); | |
| 791 set_idom(pre_exit->unique_out(), min_iff, dd_main_head); | |
| 792 // Make the true-path, must enter the main loop | |
| 793 Node *min_taken = new (C, 1) IfTrueNode( min_iff ); | |
| 794 _igvn.register_new_node_with_optimizer( min_taken ); | |
| 795 set_idom(min_taken, min_iff, dd_main_head); | |
| 796 set_loop(min_taken, loop->_parent); | |
| 797 // Plug in the true path | |
| 798 _igvn.hash_delete( main_head ); | |
| 799 main_head->set_req(LoopNode::EntryControl, min_taken); | |
| 800 set_idom(main_head, min_taken, dd_main_head); | |
| 801 | |
| 802 // Step B3: Make the fall-in values to the main-loop come from the | |
| 803 // fall-out values of the pre-loop. | |
| 804 for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) { | |
| 805 Node* main_phi = main_head->fast_out(i2); | |
| 806 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) { | |
| 807 Node *pre_phi = old_new[main_phi->_idx]; | |
| 808 Node *fallpre = clone_up_backedge_goo(pre_head->back_control(), | |
| 809 main_head->init_control(), | |
| 810 pre_phi->in(LoopNode::LoopBackControl)); | |
| 811 _igvn.hash_delete(main_phi); | |
| 812 main_phi->set_req( LoopNode::EntryControl, fallpre ); | |
| 813 } | |
| 814 } | |
| 815 | |
| 816 // Step B4: Shorten the pre-loop to run only 1 iteration (for now). | |
| 817 // RCE and alignment may change this later. | |
| 818 Node *cmp_end = pre_end->cmp_node(); | |
| 819 assert( cmp_end->in(2) == limit, "" ); | |
| 820 Node *pre_limit = new (C, 3) AddINode( init, stride ); | |
| 821 | |
| 822 // Save the original loop limit in this Opaque1 node for | |
| 823 // use by range check elimination. | |
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824 Node *pre_opaq = new (C, 3) Opaque1Node(C, pre_limit, limit); |
| 0 | 825 |
| 826 register_new_node( pre_limit, pre_head->in(0) ); | |
| 827 register_new_node( pre_opaq , pre_head->in(0) ); | |
| 828 | |
| 829 // Since no other users of pre-loop compare, I can hack limit directly | |
| 830 assert( cmp_end->outcnt() == 1, "no other users" ); | |
| 831 _igvn.hash_delete(cmp_end); | |
| 832 cmp_end->set_req(2, peel_only ? pre_limit : pre_opaq); | |
| 833 | |
| 834 // Special case for not-equal loop bounds: | |
| 835 // Change pre loop test, main loop test, and the | |
| 836 // main loop guard test to use lt or gt depending on stride | |
| 837 // direction: | |
| 838 // positive stride use < | |
| 839 // negative stride use > | |
| 840 | |
| 841 if (pre_end->in(CountedLoopEndNode::TestValue)->as_Bool()->_test._test == BoolTest::ne) { | |
| 842 | |
| 843 BoolTest::mask new_test = (main_end->stride_con() > 0) ? BoolTest::lt : BoolTest::gt; | |
| 844 // Modify pre loop end condition | |
| 845 Node* pre_bol = pre_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
| 846 BoolNode* new_bol0 = new (C, 2) BoolNode(pre_bol->in(1), new_test); | |
| 847 register_new_node( new_bol0, pre_head->in(0) ); | |
| 848 _igvn.hash_delete(pre_end); | |
| 849 pre_end->set_req(CountedLoopEndNode::TestValue, new_bol0); | |
| 850 // Modify main loop guard condition | |
| 851 assert(min_iff->in(CountedLoopEndNode::TestValue) == min_bol, "guard okay"); | |
| 852 BoolNode* new_bol1 = new (C, 2) BoolNode(min_bol->in(1), new_test); | |
| 853 register_new_node( new_bol1, new_pre_exit ); | |
| 854 _igvn.hash_delete(min_iff); | |
| 855 min_iff->set_req(CountedLoopEndNode::TestValue, new_bol1); | |
| 856 // Modify main loop end condition | |
| 857 BoolNode* main_bol = main_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
| 858 BoolNode* new_bol2 = new (C, 2) BoolNode(main_bol->in(1), new_test); | |
| 859 register_new_node( new_bol2, main_end->in(CountedLoopEndNode::TestControl) ); | |
| 860 _igvn.hash_delete(main_end); | |
| 861 main_end->set_req(CountedLoopEndNode::TestValue, new_bol2); | |
| 862 } | |
| 863 | |
| 864 // Flag main loop | |
| 865 main_head->set_main_loop(); | |
| 866 if( peel_only ) main_head->set_main_no_pre_loop(); | |
| 867 | |
| 868 // It's difficult to be precise about the trip-counts | |
| 869 // for the pre/post loops. They are usually very short, | |
| 870 // so guess that 4 trips is a reasonable value. | |
| 871 post_head->set_profile_trip_cnt(4.0); | |
| 872 pre_head->set_profile_trip_cnt(4.0); | |
| 873 | |
| 874 // Now force out all loop-invariant dominating tests. The optimizer | |
| 875 // finds some, but we _know_ they are all useless. | |
| 876 peeled_dom_test_elim(loop,old_new); | |
| 877 } | |
| 878 | |
| 879 //------------------------------is_invariant----------------------------- | |
| 880 // Return true if n is invariant | |
| 881 bool IdealLoopTree::is_invariant(Node* n) const { | |
| 1172 | 882 Node *n_c = _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; |
| 0 | 883 if (n_c->is_top()) return false; |
| 884 return !is_member(_phase->get_loop(n_c)); | |
| 885 } | |
| 886 | |
| 887 | |
| 888 //------------------------------do_unroll-------------------------------------- | |
| 889 // Unroll the loop body one step - make each trip do 2 iterations. | |
| 890 void PhaseIdealLoop::do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ) { | |
| 891 assert( LoopUnrollLimit, "" ); | |
| 892 #ifndef PRODUCT | |
| 893 if( PrintOpto && VerifyLoopOptimizations ) { | |
| 894 tty->print("Unrolling "); | |
| 895 loop->dump_head(); | |
| 896 } | |
| 897 #endif | |
| 898 CountedLoopNode *loop_head = loop->_head->as_CountedLoop(); | |
| 899 CountedLoopEndNode *loop_end = loop_head->loopexit(); | |
| 900 assert( loop_end, "" ); | |
| 901 | |
| 902 // Remember loop node count before unrolling to detect | |
| 903 // if rounds of unroll,optimize are making progress | |
| 904 loop_head->set_node_count_before_unroll(loop->_body.size()); | |
| 905 | |
| 906 Node *ctrl = loop_head->in(LoopNode::EntryControl); | |
| 907 Node *limit = loop_head->limit(); | |
| 908 Node *init = loop_head->init_trip(); | |
| 909 Node *strid = loop_head->stride(); | |
| 910 | |
| 911 Node *opaq = NULL; | |
| 912 if( adjust_min_trip ) { // If not maximally unrolling, need adjustment | |
| 913 assert( loop_head->is_main_loop(), "" ); | |
| 914 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
| 915 Node *iff = ctrl->in(0); | |
| 916 assert( iff->Opcode() == Op_If, "" ); | |
| 917 Node *bol = iff->in(1); | |
| 918 assert( bol->Opcode() == Op_Bool, "" ); | |
| 919 Node *cmp = bol->in(1); | |
| 920 assert( cmp->Opcode() == Op_CmpI, "" ); | |
| 921 opaq = cmp->in(2); | |
| 922 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
| 923 // optimized away and then another round of loop opts attempted. | |
| 924 // We can not optimize this particular loop in that case. | |
| 925 if( opaq->Opcode() != Op_Opaque1 ) | |
| 926 return; // Cannot find pre-loop! Bail out! | |
| 927 } | |
| 928 | |
| 929 C->set_major_progress(); | |
| 930 | |
| 931 // Adjust max trip count. The trip count is intentionally rounded | |
| 932 // down here (e.g. 15-> 7-> 3-> 1) because if we unwittingly over-unroll, | |
| 933 // the main, unrolled, part of the loop will never execute as it is protected | |
| 934 // by the min-trip test. See bug 4834191 for a case where we over-unrolled | |
| 935 // and later determined that part of the unrolled loop was dead. | |
| 936 loop_head->set_trip_count(loop_head->trip_count() / 2); | |
| 937 | |
| 938 // Double the count of original iterations in the unrolled loop body. | |
| 939 loop_head->double_unrolled_count(); | |
| 940 | |
| 941 // ----------- | |
| 942 // Step 2: Cut back the trip counter for an unroll amount of 2. | |
| 943 // Loop will normally trip (limit - init)/stride_con. Since it's a | |
| 944 // CountedLoop this is exact (stride divides limit-init exactly). | |
| 945 // We are going to double the loop body, so we want to knock off any | |
| 946 // odd iteration: (trip_cnt & ~1). Then back compute a new limit. | |
| 947 Node *span = new (C, 3) SubINode( limit, init ); | |
| 948 register_new_node( span, ctrl ); | |
| 949 Node *trip = new (C, 3) DivINode( 0, span, strid ); | |
| 950 register_new_node( trip, ctrl ); | |
| 951 Node *mtwo = _igvn.intcon(-2); | |
| 952 set_ctrl(mtwo, C->root()); | |
| 953 Node *rond = new (C, 3) AndINode( trip, mtwo ); | |
| 954 register_new_node( rond, ctrl ); | |
| 955 Node *spn2 = new (C, 3) MulINode( rond, strid ); | |
| 956 register_new_node( spn2, ctrl ); | |
| 957 Node *lim2 = new (C, 3) AddINode( spn2, init ); | |
| 958 register_new_node( lim2, ctrl ); | |
| 959 | |
| 960 // Hammer in the new limit | |
| 961 Node *ctrl2 = loop_end->in(0); | |
| 962 Node *cmp2 = new (C, 3) CmpINode( loop_head->incr(), lim2 ); | |
| 963 register_new_node( cmp2, ctrl2 ); | |
| 964 Node *bol2 = new (C, 2) BoolNode( cmp2, loop_end->test_trip() ); | |
| 965 register_new_node( bol2, ctrl2 ); | |
| 966 _igvn.hash_delete(loop_end); | |
| 967 loop_end->set_req(CountedLoopEndNode::TestValue, bol2); | |
| 968 | |
| 969 // Step 3: Find the min-trip test guaranteed before a 'main' loop. | |
| 970 // Make it a 1-trip test (means at least 2 trips). | |
| 971 if( adjust_min_trip ) { | |
| 972 // Guard test uses an 'opaque' node which is not shared. Hence I | |
| 973 // can edit it's inputs directly. Hammer in the new limit for the | |
| 974 // minimum-trip guard. | |
| 975 assert( opaq->outcnt() == 1, "" ); | |
| 976 _igvn.hash_delete(opaq); | |
| 977 opaq->set_req(1, lim2); | |
| 978 } | |
| 979 | |
| 980 // --------- | |
| 981 // Step 4: Clone the loop body. Move it inside the loop. This loop body | |
| 982 // represents the odd iterations; since the loop trips an even number of | |
| 983 // times its backedge is never taken. Kill the backedge. | |
| 984 uint dd = dom_depth(loop_head); | |
| 985 clone_loop( loop, old_new, dd ); | |
| 986 | |
| 987 // Make backedges of the clone equal to backedges of the original. | |
| 988 // Make the fall-in from the original come from the fall-out of the clone. | |
| 989 for (DUIterator_Fast jmax, j = loop_head->fast_outs(jmax); j < jmax; j++) { | |
| 990 Node* phi = loop_head->fast_out(j); | |
| 991 if( phi->is_Phi() && phi->in(0) == loop_head && phi->outcnt() > 0 ) { | |
| 992 Node *newphi = old_new[phi->_idx]; | |
| 993 _igvn.hash_delete( phi ); | |
| 994 _igvn.hash_delete( newphi ); | |
| 995 | |
| 996 phi ->set_req(LoopNode:: EntryControl, newphi->in(LoopNode::LoopBackControl)); | |
| 997 newphi->set_req(LoopNode::LoopBackControl, phi ->in(LoopNode::LoopBackControl)); | |
| 998 phi ->set_req(LoopNode::LoopBackControl, C->top()); | |
| 999 } | |
| 1000 } | |
| 1001 Node *clone_head = old_new[loop_head->_idx]; | |
| 1002 _igvn.hash_delete( clone_head ); | |
| 1003 loop_head ->set_req(LoopNode:: EntryControl, clone_head->in(LoopNode::LoopBackControl)); | |
| 1004 clone_head->set_req(LoopNode::LoopBackControl, loop_head ->in(LoopNode::LoopBackControl)); | |
| 1005 loop_head ->set_req(LoopNode::LoopBackControl, C->top()); | |
| 1006 loop->_head = clone_head; // New loop header | |
| 1007 | |
| 1008 set_idom(loop_head, loop_head ->in(LoopNode::EntryControl), dd); | |
| 1009 set_idom(clone_head, clone_head->in(LoopNode::EntryControl), dd); | |
| 1010 | |
| 1011 // Kill the clone's backedge | |
| 1012 Node *newcle = old_new[loop_end->_idx]; | |
| 1013 _igvn.hash_delete( newcle ); | |
| 1014 Node *one = _igvn.intcon(1); | |
| 1015 set_ctrl(one, C->root()); | |
| 1016 newcle->set_req(1, one); | |
| 1017 // Force clone into same loop body | |
| 1018 uint max = loop->_body.size(); | |
| 1019 for( uint k = 0; k < max; k++ ) { | |
| 1020 Node *old = loop->_body.at(k); | |
| 1021 Node *nnn = old_new[old->_idx]; | |
| 1022 loop->_body.push(nnn); | |
| 1023 if (!has_ctrl(old)) | |
| 1024 set_loop(nnn, loop); | |
| 1025 } | |
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1027 loop->record_for_igvn(); |
| 0 | 1028 } |
| 1029 | |
| 1030 //------------------------------do_maximally_unroll---------------------------- | |
| 1031 | |
| 1032 void PhaseIdealLoop::do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ) { | |
| 1033 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
| 1034 assert( cl->trip_count() > 0, ""); | |
| 1035 | |
| 1036 // If loop is tripping an odd number of times, peel odd iteration | |
| 1037 if( (cl->trip_count() & 1) == 1 ) { | |
| 1038 do_peeling( loop, old_new ); | |
| 1039 } | |
| 1040 | |
| 1041 // Now its tripping an even number of times remaining. Double loop body. | |
| 1042 // Do not adjust pre-guards; they are not needed and do not exist. | |
| 1043 if( cl->trip_count() > 0 ) { | |
| 1044 do_unroll( loop, old_new, false ); | |
| 1045 } | |
| 1046 } | |
| 1047 | |
| 1048 //------------------------------dominates_backedge--------------------------------- | |
| 1049 // Returns true if ctrl is executed on every complete iteration | |
| 1050 bool IdealLoopTree::dominates_backedge(Node* ctrl) { | |
| 1051 assert(ctrl->is_CFG(), "must be control"); | |
| 1052 Node* backedge = _head->as_Loop()->in(LoopNode::LoopBackControl); | |
| 1053 return _phase->dom_lca_internal(ctrl, backedge) == ctrl; | |
| 1054 } | |
| 1055 | |
| 1056 //------------------------------add_constraint--------------------------------- | |
| 1057 // Constrain the main loop iterations so the condition: | |
| 1058 // scale_con * I + offset < limit | |
| 1059 // always holds true. That is, either increase the number of iterations in | |
| 1060 // the pre-loop or the post-loop until the condition holds true in the main | |
| 1061 // loop. Stride, scale, offset and limit are all loop invariant. Further, | |
| 1062 // stride and scale are constants (offset and limit often are). | |
| 1063 void PhaseIdealLoop::add_constraint( int stride_con, int scale_con, Node *offset, Node *limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ) { | |
| 1064 | |
| 1065 // Compute "I :: (limit-offset)/scale_con" | |
| 1066 Node *con = new (C, 3) SubINode( limit, offset ); | |
| 1067 register_new_node( con, pre_ctrl ); | |
| 1068 Node *scale = _igvn.intcon(scale_con); | |
| 1069 set_ctrl(scale, C->root()); | |
| 1070 Node *X = new (C, 3) DivINode( 0, con, scale ); | |
| 1071 register_new_node( X, pre_ctrl ); | |
| 1072 | |
| 1073 // For positive stride, the pre-loop limit always uses a MAX function | |
| 1074 // and the main loop a MIN function. For negative stride these are | |
| 1075 // reversed. | |
| 1076 | |
| 1077 // Also for positive stride*scale the affine function is increasing, so the | |
| 1078 // pre-loop must check for underflow and the post-loop for overflow. | |
| 1079 // Negative stride*scale reverses this; pre-loop checks for overflow and | |
| 1080 // post-loop for underflow. | |
| 1081 if( stride_con*scale_con > 0 ) { | |
| 1082 // Compute I < (limit-offset)/scale_con | |
| 1083 // Adjust main-loop last iteration to be MIN/MAX(main_loop,X) | |
| 1084 *main_limit = (stride_con > 0) | |
| 1085 ? (Node*)(new (C, 3) MinINode( *main_limit, X )) | |
| 1086 : (Node*)(new (C, 3) MaxINode( *main_limit, X )); | |
| 1087 register_new_node( *main_limit, pre_ctrl ); | |
| 1088 | |
| 1089 } else { | |
| 1090 // Compute (limit-offset)/scale_con + SGN(-scale_con) <= I | |
| 1091 // Add the negation of the main-loop constraint to the pre-loop. | |
| 1092 // See footnote [++] below for a derivation of the limit expression. | |
| 1093 Node *incr = _igvn.intcon(scale_con > 0 ? -1 : 1); | |
| 1094 set_ctrl(incr, C->root()); | |
| 1095 Node *adj = new (C, 3) AddINode( X, incr ); | |
| 1096 register_new_node( adj, pre_ctrl ); | |
| 1097 *pre_limit = (scale_con > 0) | |
| 1098 ? (Node*)new (C, 3) MinINode( *pre_limit, adj ) | |
| 1099 : (Node*)new (C, 3) MaxINode( *pre_limit, adj ); | |
| 1100 register_new_node( *pre_limit, pre_ctrl ); | |
| 1101 | |
| 1102 // [++] Here's the algebra that justifies the pre-loop limit expression: | |
| 1103 // | |
| 1104 // NOT( scale_con * I + offset < limit ) | |
| 1105 // == | |
| 1106 // scale_con * I + offset >= limit | |
| 1107 // == | |
| 1108 // SGN(scale_con) * I >= (limit-offset)/|scale_con| | |
| 1109 // == | |
| 1110 // (limit-offset)/|scale_con| <= I * SGN(scale_con) | |
| 1111 // == | |
| 1112 // (limit-offset)/|scale_con|-1 < I * SGN(scale_con) | |
| 1113 // == | |
| 1114 // ( if (scale_con > 0) /*common case*/ | |
| 1115 // (limit-offset)/scale_con - 1 < I | |
| 1116 // else | |
| 1117 // (limit-offset)/scale_con + 1 > I | |
| 1118 // ) | |
| 1119 // ( if (scale_con > 0) /*common case*/ | |
| 1120 // (limit-offset)/scale_con + SGN(-scale_con) < I | |
| 1121 // else | |
| 1122 // (limit-offset)/scale_con + SGN(-scale_con) > I | |
| 1123 } | |
| 1124 } | |
| 1125 | |
| 1126 | |
| 1127 //------------------------------is_scaled_iv--------------------------------- | |
| 1128 // Return true if exp is a constant times an induction var | |
| 1129 bool PhaseIdealLoop::is_scaled_iv(Node* exp, Node* iv, int* p_scale) { | |
| 1130 if (exp == iv) { | |
| 1131 if (p_scale != NULL) { | |
| 1132 *p_scale = 1; | |
| 1133 } | |
| 1134 return true; | |
| 1135 } | |
| 1136 int opc = exp->Opcode(); | |
| 1137 if (opc == Op_MulI) { | |
| 1138 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
| 1139 if (p_scale != NULL) { | |
| 1140 *p_scale = exp->in(2)->get_int(); | |
| 1141 } | |
| 1142 return true; | |
| 1143 } | |
| 1144 if (exp->in(2) == iv && exp->in(1)->is_Con()) { | |
| 1145 if (p_scale != NULL) { | |
| 1146 *p_scale = exp->in(1)->get_int(); | |
| 1147 } | |
| 1148 return true; | |
| 1149 } | |
| 1150 } else if (opc == Op_LShiftI) { | |
| 1151 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
| 1152 if (p_scale != NULL) { | |
| 1153 *p_scale = 1 << exp->in(2)->get_int(); | |
| 1154 } | |
| 1155 return true; | |
| 1156 } | |
| 1157 } | |
| 1158 return false; | |
| 1159 } | |
| 1160 | |
| 1161 //-----------------------------is_scaled_iv_plus_offset------------------------------ | |
| 1162 // Return true if exp is a simple induction variable expression: k1*iv + (invar + k2) | |
| 1163 bool PhaseIdealLoop::is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth) { | |
| 1164 if (is_scaled_iv(exp, iv, p_scale)) { | |
| 1165 if (p_offset != NULL) { | |
| 1166 Node *zero = _igvn.intcon(0); | |
| 1167 set_ctrl(zero, C->root()); | |
| 1168 *p_offset = zero; | |
| 1169 } | |
| 1170 return true; | |
| 1171 } | |
| 1172 int opc = exp->Opcode(); | |
| 1173 if (opc == Op_AddI) { | |
| 1174 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
| 1175 if (p_offset != NULL) { | |
| 1176 *p_offset = exp->in(2); | |
| 1177 } | |
| 1178 return true; | |
| 1179 } | |
| 1180 if (exp->in(2)->is_Con()) { | |
| 1181 Node* offset2 = NULL; | |
| 1182 if (depth < 2 && | |
| 1183 is_scaled_iv_plus_offset(exp->in(1), iv, p_scale, | |
| 1184 p_offset != NULL ? &offset2 : NULL, depth+1)) { | |
| 1185 if (p_offset != NULL) { | |
| 1186 Node *ctrl_off2 = get_ctrl(offset2); | |
| 1187 Node* offset = new (C, 3) AddINode(offset2, exp->in(2)); | |
| 1188 register_new_node(offset, ctrl_off2); | |
| 1189 *p_offset = offset; | |
| 1190 } | |
| 1191 return true; | |
| 1192 } | |
| 1193 } | |
| 1194 } else if (opc == Op_SubI) { | |
| 1195 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
| 1196 if (p_offset != NULL) { | |
| 1197 Node *zero = _igvn.intcon(0); | |
| 1198 set_ctrl(zero, C->root()); | |
| 1199 Node *ctrl_off = get_ctrl(exp->in(2)); | |
| 1200 Node* offset = new (C, 3) SubINode(zero, exp->in(2)); | |
| 1201 register_new_node(offset, ctrl_off); | |
| 1202 *p_offset = offset; | |
| 1203 } | |
| 1204 return true; | |
| 1205 } | |
| 1206 if (is_scaled_iv(exp->in(2), iv, p_scale)) { | |
| 1207 if (p_offset != NULL) { | |
| 1208 *p_scale *= -1; | |
| 1209 *p_offset = exp->in(1); | |
| 1210 } | |
| 1211 return true; | |
| 1212 } | |
| 1213 } | |
| 1214 return false; | |
| 1215 } | |
| 1216 | |
| 1217 //------------------------------do_range_check--------------------------------- | |
| 1218 // Eliminate range-checks and other trip-counter vs loop-invariant tests. | |
| 1219 void PhaseIdealLoop::do_range_check( IdealLoopTree *loop, Node_List &old_new ) { | |
| 1220 #ifndef PRODUCT | |
| 1221 if( PrintOpto && VerifyLoopOptimizations ) { | |
| 1222 tty->print("Range Check Elimination "); | |
| 1223 loop->dump_head(); | |
| 1224 } | |
| 1225 #endif | |
| 1226 assert( RangeCheckElimination, "" ); | |
| 1227 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
| 1228 assert( cl->is_main_loop(), "" ); | |
| 1229 | |
| 1230 // Find the trip counter; we are iteration splitting based on it | |
| 1231 Node *trip_counter = cl->phi(); | |
| 1232 // Find the main loop limit; we will trim it's iterations | |
| 1233 // to not ever trip end tests | |
| 1234 Node *main_limit = cl->limit(); | |
| 1235 // Find the pre-loop limit; we will expand it's iterations to | |
| 1236 // not ever trip low tests. | |
| 1237 Node *ctrl = cl->in(LoopNode::EntryControl); | |
| 1238 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
| 1239 Node *iffm = ctrl->in(0); | |
| 1240 assert( iffm->Opcode() == Op_If, "" ); | |
| 1241 Node *p_f = iffm->in(0); | |
| 1242 assert( p_f->Opcode() == Op_IfFalse, "" ); | |
| 1243 CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); | |
| 1244 assert( pre_end->loopnode()->is_pre_loop(), "" ); | |
| 1245 Node *pre_opaq1 = pre_end->limit(); | |
| 1246 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
| 1247 // optimized away and then another round of loop opts attempted. | |
| 1248 // We can not optimize this particular loop in that case. | |
| 1249 if( pre_opaq1->Opcode() != Op_Opaque1 ) | |
| 1250 return; | |
| 1251 Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1; | |
| 1252 Node *pre_limit = pre_opaq->in(1); | |
| 1253 | |
| 1254 // Where do we put new limit calculations | |
| 1255 Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl); | |
| 1256 | |
| 1257 // Ensure the original loop limit is available from the | |
| 1258 // pre-loop Opaque1 node. | |
| 1259 Node *orig_limit = pre_opaq->original_loop_limit(); | |
| 1260 if( orig_limit == NULL || _igvn.type(orig_limit) == Type::TOP ) | |
| 1261 return; | |
| 1262 | |
| 1263 // Need to find the main-loop zero-trip guard | |
| 1264 Node *bolzm = iffm->in(1); | |
| 1265 assert( bolzm->Opcode() == Op_Bool, "" ); | |
| 1266 Node *cmpzm = bolzm->in(1); | |
| 1267 assert( cmpzm->is_Cmp(), "" ); | |
| 1268 Node *opqzm = cmpzm->in(2); | |
| 1269 if( opqzm->Opcode() != Op_Opaque1 ) | |
| 1270 return; | |
| 1271 assert( opqzm->in(1) == main_limit, "do not understand situation" ); | |
| 1272 | |
| 1273 // Must know if its a count-up or count-down loop | |
| 1274 | |
| 1275 // protect against stride not being a constant | |
| 1276 if ( !cl->stride_is_con() ) { | |
| 1277 return; | |
| 1278 } | |
| 1279 int stride_con = cl->stride_con(); | |
| 1280 Node *zero = _igvn.intcon(0); | |
| 1281 Node *one = _igvn.intcon(1); | |
| 1282 set_ctrl(zero, C->root()); | |
| 1283 set_ctrl(one, C->root()); | |
| 1284 | |
| 1285 // Range checks that do not dominate the loop backedge (ie. | |
| 1286 // conditionally executed) can lengthen the pre loop limit beyond | |
| 1287 // the original loop limit. To prevent this, the pre limit is | |
| 1288 // (for stride > 0) MINed with the original loop limit (MAXed | |
| 1289 // stride < 0) when some range_check (rc) is conditionally | |
| 1290 // executed. | |
| 1291 bool conditional_rc = false; | |
| 1292 | |
| 1293 // Check loop body for tests of trip-counter plus loop-invariant vs | |
| 1294 // loop-invariant. | |
| 1295 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
| 1296 Node *iff = loop->_body[i]; | |
| 1297 if( iff->Opcode() == Op_If ) { // Test? | |
| 1298 | |
| 1299 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
| 1300 // we need loop unswitching instead of iteration splitting. | |
| 1301 Node *exit = loop->is_loop_exit(iff); | |
| 1302 if( !exit ) continue; | |
| 1303 int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0; | |
| 1304 | |
| 1305 // Get boolean condition to test | |
| 1306 Node *i1 = iff->in(1); | |
| 1307 if( !i1->is_Bool() ) continue; | |
| 1308 BoolNode *bol = i1->as_Bool(); | |
| 1309 BoolTest b_test = bol->_test; | |
| 1310 // Flip sense of test if exit condition is flipped | |
| 1311 if( flip ) | |
| 1312 b_test = b_test.negate(); | |
| 1313 | |
| 1314 // Get compare | |
| 1315 Node *cmp = bol->in(1); | |
| 1316 | |
| 1317 // Look for trip_counter + offset vs limit | |
| 1318 Node *rc_exp = cmp->in(1); | |
| 1319 Node *limit = cmp->in(2); | |
| 1320 jint scale_con= 1; // Assume trip counter not scaled | |
| 1321 | |
| 1322 Node *limit_c = get_ctrl(limit); | |
| 1323 if( loop->is_member(get_loop(limit_c) ) ) { | |
| 1324 // Compare might have operands swapped; commute them | |
| 1325 b_test = b_test.commute(); | |
| 1326 rc_exp = cmp->in(2); | |
| 1327 limit = cmp->in(1); | |
| 1328 limit_c = get_ctrl(limit); | |
| 1329 if( loop->is_member(get_loop(limit_c) ) ) | |
| 1330 continue; // Both inputs are loop varying; cannot RCE | |
| 1331 } | |
| 1332 // Here we know 'limit' is loop invariant | |
| 1333 | |
| 1334 // 'limit' maybe pinned below the zero trip test (probably from a | |
| 1335 // previous round of rce), in which case, it can't be used in the | |
| 1336 // zero trip test expression which must occur before the zero test's if. | |
| 1337 if( limit_c == ctrl ) { | |
| 1338 continue; // Don't rce this check but continue looking for other candidates. | |
| 1339 } | |
| 1340 | |
| 1341 // Check for scaled induction variable plus an offset | |
| 1342 Node *offset = NULL; | |
| 1343 | |
| 1344 if (!is_scaled_iv_plus_offset(rc_exp, trip_counter, &scale_con, &offset)) { | |
| 1345 continue; | |
| 1346 } | |
| 1347 | |
| 1348 Node *offset_c = get_ctrl(offset); | |
| 1349 if( loop->is_member( get_loop(offset_c) ) ) | |
| 1350 continue; // Offset is not really loop invariant | |
| 1351 // Here we know 'offset' is loop invariant. | |
| 1352 | |
| 1353 // As above for the 'limit', the 'offset' maybe pinned below the | |
| 1354 // zero trip test. | |
| 1355 if( offset_c == ctrl ) { | |
| 1356 continue; // Don't rce this check but continue looking for other candidates. | |
| 1357 } | |
| 1358 | |
| 1359 // At this point we have the expression as: | |
| 1360 // scale_con * trip_counter + offset :: limit | |
| 1361 // where scale_con, offset and limit are loop invariant. Trip_counter | |
| 1362 // monotonically increases by stride_con, a constant. Both (or either) | |
| 1363 // stride_con and scale_con can be negative which will flip about the | |
| 1364 // sense of the test. | |
| 1365 | |
| 1366 // Adjust pre and main loop limits to guard the correct iteration set | |
| 1367 if( cmp->Opcode() == Op_CmpU ) {// Unsigned compare is really 2 tests | |
| 1368 if( b_test._test == BoolTest::lt ) { // Range checks always use lt | |
| 1369 // The overflow limit: scale*I+offset < limit | |
| 1370 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
| 1371 // The underflow limit: 0 <= scale*I+offset. | |
| 1372 // Some math yields: -scale*I-(offset+1) < 0 | |
| 1373 Node *plus_one = new (C, 3) AddINode( offset, one ); | |
| 1374 register_new_node( plus_one, pre_ctrl ); | |
| 1375 Node *neg_offset = new (C, 3) SubINode( zero, plus_one ); | |
| 1376 register_new_node( neg_offset, pre_ctrl ); | |
| 1377 add_constraint( stride_con, -scale_con, neg_offset, zero, pre_ctrl, &pre_limit, &main_limit ); | |
| 1378 if (!conditional_rc) { | |
| 1379 conditional_rc = !loop->dominates_backedge(iff); | |
| 1380 } | |
| 1381 } else { | |
| 1382 #ifndef PRODUCT | |
| 1383 if( PrintOpto ) | |
| 1384 tty->print_cr("missed RCE opportunity"); | |
| 1385 #endif | |
| 1386 continue; // In release mode, ignore it | |
| 1387 } | |
| 1388 } else { // Otherwise work on normal compares | |
| 1389 switch( b_test._test ) { | |
| 1390 case BoolTest::ge: // Convert X >= Y to -X <= -Y | |
| 1391 scale_con = -scale_con; | |
| 1392 offset = new (C, 3) SubINode( zero, offset ); | |
| 1393 register_new_node( offset, pre_ctrl ); | |
| 1394 limit = new (C, 3) SubINode( zero, limit ); | |
| 1395 register_new_node( limit, pre_ctrl ); | |
| 1396 // Fall into LE case | |
| 1397 case BoolTest::le: // Convert X <= Y to X < Y+1 | |
| 1398 limit = new (C, 3) AddINode( limit, one ); | |
| 1399 register_new_node( limit, pre_ctrl ); | |
| 1400 // Fall into LT case | |
| 1401 case BoolTest::lt: | |
| 1402 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
| 1403 if (!conditional_rc) { | |
| 1404 conditional_rc = !loop->dominates_backedge(iff); | |
| 1405 } | |
| 1406 break; | |
| 1407 default: | |
| 1408 #ifndef PRODUCT | |
| 1409 if( PrintOpto ) | |
| 1410 tty->print_cr("missed RCE opportunity"); | |
| 1411 #endif | |
| 1412 continue; // Unhandled case | |
| 1413 } | |
| 1414 } | |
| 1415 | |
| 1416 // Kill the eliminated test | |
| 1417 C->set_major_progress(); | |
| 1418 Node *kill_con = _igvn.intcon( 1-flip ); | |
| 1419 set_ctrl(kill_con, C->root()); | |
| 1420 _igvn.hash_delete(iff); | |
| 1421 iff->set_req(1, kill_con); | |
| 1422 _igvn._worklist.push(iff); | |
| 1423 // Find surviving projection | |
| 1424 assert(iff->is_If(), ""); | |
| 1425 ProjNode* dp = ((IfNode*)iff)->proj_out(1-flip); | |
| 1426 // Find loads off the surviving projection; remove their control edge | |
| 1427 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
| 1428 Node* cd = dp->fast_out(i); // Control-dependent node | |
| 1429 if( cd->is_Load() ) { // Loads can now float around in the loop | |
| 1430 _igvn.hash_delete(cd); | |
| 1431 // Allow the load to float around in the loop, or before it | |
| 1432 // but NOT before the pre-loop. | |
| 1433 cd->set_req(0, ctrl); // ctrl, not NULL | |
| 1434 _igvn._worklist.push(cd); | |
| 1435 --i; | |
| 1436 --imax; | |
| 1437 } | |
| 1438 } | |
| 1439 | |
| 1440 } // End of is IF | |
| 1441 | |
| 1442 } | |
| 1443 | |
| 1444 // Update loop limits | |
| 1445 if (conditional_rc) { | |
| 1446 pre_limit = (stride_con > 0) ? (Node*)new (C,3) MinINode(pre_limit, orig_limit) | |
| 1447 : (Node*)new (C,3) MaxINode(pre_limit, orig_limit); | |
| 1448 register_new_node(pre_limit, pre_ctrl); | |
| 1449 } | |
| 1450 _igvn.hash_delete(pre_opaq); | |
| 1451 pre_opaq->set_req(1, pre_limit); | |
| 1452 | |
| 1453 // Note:: we are making the main loop limit no longer precise; | |
| 1454 // need to round up based on stride. | |
| 1455 if( stride_con != 1 && stride_con != -1 ) { // Cutout for common case | |
| 1456 // "Standard" round-up logic: ([main_limit-init+(y-1)]/y)*y+init | |
| 1457 // Hopefully, compiler will optimize for powers of 2. | |
| 1458 Node *ctrl = get_ctrl(main_limit); | |
| 1459 Node *stride = cl->stride(); | |
| 1460 Node *init = cl->init_trip(); | |
| 1461 Node *span = new (C, 3) SubINode(main_limit,init); | |
| 1462 register_new_node(span,ctrl); | |
| 1463 Node *rndup = _igvn.intcon(stride_con + ((stride_con>0)?-1:1)); | |
| 1464 Node *add = new (C, 3) AddINode(span,rndup); | |
| 1465 register_new_node(add,ctrl); | |
| 1466 Node *div = new (C, 3) DivINode(0,add,stride); | |
| 1467 register_new_node(div,ctrl); | |
| 1468 Node *mul = new (C, 3) MulINode(div,stride); | |
| 1469 register_new_node(mul,ctrl); | |
| 1470 Node *newlim = new (C, 3) AddINode(mul,init); | |
| 1471 register_new_node(newlim,ctrl); | |
| 1472 main_limit = newlim; | |
| 1473 } | |
| 1474 | |
| 1475 Node *main_cle = cl->loopexit(); | |
| 1476 Node *main_bol = main_cle->in(1); | |
| 1477 // Hacking loop bounds; need private copies of exit test | |
| 1478 if( main_bol->outcnt() > 1 ) {// BoolNode shared? | |
| 1479 _igvn.hash_delete(main_cle); | |
| 1480 main_bol = main_bol->clone();// Clone a private BoolNode | |
| 1481 register_new_node( main_bol, main_cle->in(0) ); | |
| 1482 main_cle->set_req(1,main_bol); | |
| 1483 } | |
| 1484 Node *main_cmp = main_bol->in(1); | |
| 1485 if( main_cmp->outcnt() > 1 ) { // CmpNode shared? | |
| 1486 _igvn.hash_delete(main_bol); | |
| 1487 main_cmp = main_cmp->clone();// Clone a private CmpNode | |
| 1488 register_new_node( main_cmp, main_cle->in(0) ); | |
| 1489 main_bol->set_req(1,main_cmp); | |
| 1490 } | |
| 1491 // Hack the now-private loop bounds | |
| 1492 _igvn.hash_delete(main_cmp); | |
| 1493 main_cmp->set_req(2, main_limit); | |
| 1494 _igvn._worklist.push(main_cmp); | |
| 1495 // The OpaqueNode is unshared by design | |
| 1496 _igvn.hash_delete(opqzm); | |
| 1497 assert( opqzm->outcnt() == 1, "cannot hack shared node" ); | |
| 1498 opqzm->set_req(1,main_limit); | |
| 1499 _igvn._worklist.push(opqzm); | |
| 1500 } | |
| 1501 | |
| 1502 //------------------------------DCE_loop_body---------------------------------- | |
| 1503 // Remove simplistic dead code from loop body | |
| 1504 void IdealLoopTree::DCE_loop_body() { | |
| 1505 for( uint i = 0; i < _body.size(); i++ ) | |
| 1506 if( _body.at(i)->outcnt() == 0 ) | |
| 1507 _body.map( i--, _body.pop() ); | |
| 1508 } | |
| 1509 | |
| 1510 | |
| 1511 //------------------------------adjust_loop_exit_prob-------------------------- | |
| 1512 // Look for loop-exit tests with the 50/50 (or worse) guesses from the parsing stage. | |
| 1513 // Replace with a 1-in-10 exit guess. | |
| 1514 void IdealLoopTree::adjust_loop_exit_prob( PhaseIdealLoop *phase ) { | |
| 1515 Node *test = tail(); | |
| 1516 while( test != _head ) { | |
| 1517 uint top = test->Opcode(); | |
| 1518 if( top == Op_IfTrue || top == Op_IfFalse ) { | |
| 1519 int test_con = ((ProjNode*)test)->_con; | |
| 1520 assert(top == (uint)(test_con? Op_IfTrue: Op_IfFalse), "sanity"); | |
| 1521 IfNode *iff = test->in(0)->as_If(); | |
| 1522 if( iff->outcnt() == 2 ) { // Ignore dead tests | |
| 1523 Node *bol = iff->in(1); | |
| 1524 if( bol && bol->req() > 1 && bol->in(1) && | |
| 1525 ((bol->in(1)->Opcode() == Op_StorePConditional ) || | |
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1526 (bol->in(1)->Opcode() == Op_StoreIConditional ) || |
| 0 | 1527 (bol->in(1)->Opcode() == Op_StoreLConditional ) || |
| 1528 (bol->in(1)->Opcode() == Op_CompareAndSwapI ) || | |
| 1529 (bol->in(1)->Opcode() == Op_CompareAndSwapL ) || | |
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1530 (bol->in(1)->Opcode() == Op_CompareAndSwapP ) || |
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1531 (bol->in(1)->Opcode() == Op_CompareAndSwapN ))) |
| 0 | 1532 return; // Allocation loops RARELY take backedge |
| 1533 // Find the OTHER exit path from the IF | |
| 1534 Node* ex = iff->proj_out(1-test_con); | |
| 1535 float p = iff->_prob; | |
| 1536 if( !phase->is_member( this, ex ) && iff->_fcnt == COUNT_UNKNOWN ) { | |
| 1537 if( top == Op_IfTrue ) { | |
| 1538 if( p < (PROB_FAIR + PROB_UNLIKELY_MAG(3))) { | |
| 1539 iff->_prob = PROB_STATIC_FREQUENT; | |
| 1540 } | |
| 1541 } else { | |
| 1542 if( p > (PROB_FAIR - PROB_UNLIKELY_MAG(3))) { | |
| 1543 iff->_prob = PROB_STATIC_INFREQUENT; | |
| 1544 } | |
| 1545 } | |
| 1546 } | |
| 1547 } | |
| 1548 } | |
| 1549 test = phase->idom(test); | |
| 1550 } | |
| 1551 } | |
| 1552 | |
| 1553 | |
| 1554 //------------------------------policy_do_remove_empty_loop-------------------- | |
| 1555 // Micro-benchmark spamming. Policy is to always remove empty loops. | |
| 1556 // The 'DO' part is to replace the trip counter with the value it will | |
| 1557 // have on the last iteration. This will break the loop. | |
| 1558 bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) { | |
| 1559 // Minimum size must be empty loop | |
| 1560 if( _body.size() > 7/*number of nodes in an empty loop*/ ) return false; | |
| 1561 | |
| 1562 if( !_head->is_CountedLoop() ) return false; // Dead loop | |
| 1563 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 1564 if( !cl->loopexit() ) return false; // Malformed loop | |
| 1565 if( !phase->is_member(this,phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)) ) ) | |
| 1566 return false; // Infinite loop | |
| 1567 #ifndef PRODUCT | |
| 1568 if( PrintOpto ) | |
| 1569 tty->print_cr("Removing empty loop"); | |
| 1570 #endif | |
| 1571 #ifdef ASSERT | |
| 1572 // Ensure only one phi which is the iv. | |
| 1573 Node* iv = NULL; | |
| 1574 for (DUIterator_Fast imax, i = cl->fast_outs(imax); i < imax; i++) { | |
| 1575 Node* n = cl->fast_out(i); | |
| 1576 if (n->Opcode() == Op_Phi) { | |
| 1577 assert(iv == NULL, "Too many phis" ); | |
| 1578 iv = n; | |
| 1579 } | |
| 1580 } | |
| 1581 assert(iv == cl->phi(), "Wrong phi" ); | |
| 1582 #endif | |
| 1583 // Replace the phi at loop head with the final value of the last | |
| 1584 // iteration. Then the CountedLoopEnd will collapse (backedge never | |
| 1585 // taken) and all loop-invariant uses of the exit values will be correct. | |
| 1586 Node *phi = cl->phi(); | |
| 1587 Node *final = new (phase->C, 3) SubINode( cl->limit(), cl->stride() ); | |
| 1588 phase->register_new_node(final,cl->in(LoopNode::EntryControl)); | |
| 1589 phase->_igvn.hash_delete(phi); | |
| 1590 phase->_igvn.subsume_node(phi,final); | |
| 1591 phase->C->set_major_progress(); | |
| 1592 return true; | |
| 1593 } | |
| 1594 | |
| 1595 | |
| 1596 //============================================================================= | |
| 1597 //------------------------------iteration_split_impl--------------------------- | |
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1598 bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ) { |
| 0 | 1599 // Check and remove empty loops (spam micro-benchmarks) |
| 1600 if( policy_do_remove_empty_loop(phase) ) | |
| 1172 | 1601 return true; // Here we removed an empty loop |
| 0 | 1602 |
| 1603 bool should_peel = policy_peeling(phase); // Should we peel? | |
| 1604 | |
| 1605 bool should_unswitch = policy_unswitching(phase); | |
| 1606 | |
| 1607 // Non-counted loops may be peeled; exactly 1 iteration is peeled. | |
| 1608 // This removes loop-invariant tests (usually null checks). | |
| 1609 if( !_head->is_CountedLoop() ) { // Non-counted loop | |
| 1610 if (PartialPeelLoop && phase->partial_peel(this, old_new)) { | |
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1611 // Partial peel succeeded so terminate this round of loop opts |
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1612 return false; |
| 0 | 1613 } |
| 1614 if( should_peel ) { // Should we peel? | |
| 1615 #ifndef PRODUCT | |
| 1616 if (PrintOpto) tty->print_cr("should_peel"); | |
| 1617 #endif | |
| 1618 phase->do_peeling(this,old_new); | |
| 1619 } else if( should_unswitch ) { | |
| 1620 phase->do_unswitching(this, old_new); | |
| 1621 } | |
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1622 return true; |
| 0 | 1623 } |
| 1624 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 1625 | |
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1626 if( !cl->loopexit() ) return true; // Ignore various kinds of broken loops |
| 0 | 1627 |
| 1628 // Do nothing special to pre- and post- loops | |
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1629 if( cl->is_pre_loop() || cl->is_post_loop() ) return true; |
| 0 | 1630 |
| 1631 // Compute loop trip count from profile data | |
| 1632 compute_profile_trip_cnt(phase); | |
| 1633 | |
| 1634 // Before attempting fancy unrolling, RCE or alignment, see if we want | |
| 1635 // to completely unroll this loop or do loop unswitching. | |
| 1636 if( cl->is_normal_loop() ) { | |
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1637 if (should_unswitch) { |
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1638 phase->do_unswitching(this, old_new); |
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1639 return true; |
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1640 } |
| 0 | 1641 bool should_maximally_unroll = policy_maximally_unroll(phase); |
| 1642 if( should_maximally_unroll ) { | |
| 1643 // Here we did some unrolling and peeling. Eventually we will | |
| 1644 // completely unroll this loop and it will no longer be a loop. | |
| 1645 phase->do_maximally_unroll(this,old_new); | |
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1646 return true; |
| 0 | 1647 } |
| 1648 } | |
| 1649 | |
| 1650 | |
| 1651 // Counted loops may be peeled, may need some iterations run up | |
| 1652 // front for RCE, and may want to align loop refs to a cache | |
| 1653 // line. Thus we clone a full loop up front whose trip count is | |
| 1654 // at least 1 (if peeling), but may be several more. | |
| 1655 | |
| 1656 // The main loop will start cache-line aligned with at least 1 | |
| 1657 // iteration of the unrolled body (zero-trip test required) and | |
| 1658 // will have some range checks removed. | |
| 1659 | |
| 1660 // A post-loop will finish any odd iterations (leftover after | |
| 1661 // unrolling), plus any needed for RCE purposes. | |
| 1662 | |
| 1663 bool should_unroll = policy_unroll(phase); | |
| 1664 | |
| 1665 bool should_rce = policy_range_check(phase); | |
| 1666 | |
| 1667 bool should_align = policy_align(phase); | |
| 1668 | |
| 1669 // If not RCE'ing (iteration splitting) or Aligning, then we do not | |
| 1670 // need a pre-loop. We may still need to peel an initial iteration but | |
| 1671 // we will not be needing an unknown number of pre-iterations. | |
| 1672 // | |
| 1673 // Basically, if may_rce_align reports FALSE first time through, | |
| 1674 // we will not be able to later do RCE or Aligning on this loop. | |
| 1675 bool may_rce_align = !policy_peel_only(phase) || should_rce || should_align; | |
| 1676 | |
| 1677 // If we have any of these conditions (RCE, alignment, unrolling) met, then | |
| 1678 // we switch to the pre-/main-/post-loop model. This model also covers | |
| 1679 // peeling. | |
| 1680 if( should_rce || should_align || should_unroll ) { | |
| 1681 if( cl->is_normal_loop() ) // Convert to 'pre/main/post' loops | |
| 1682 phase->insert_pre_post_loops(this,old_new, !may_rce_align); | |
| 1683 | |
| 1684 // Adjust the pre- and main-loop limits to let the pre and post loops run | |
| 1685 // with full checks, but the main-loop with no checks. Remove said | |
| 1686 // checks from the main body. | |
| 1687 if( should_rce ) | |
| 1688 phase->do_range_check(this,old_new); | |
| 1689 | |
| 1690 // Double loop body for unrolling. Adjust the minimum-trip test (will do | |
| 1691 // twice as many iterations as before) and the main body limit (only do | |
| 1692 // an even number of trips). If we are peeling, we might enable some RCE | |
| 1693 // and we'd rather unroll the post-RCE'd loop SO... do not unroll if | |
| 1694 // peeling. | |
| 1172 | 1695 if( should_unroll && !should_peel ) |
| 1696 phase->do_unroll(this,old_new, true); | |
| 0 | 1697 |
| 1698 // Adjust the pre-loop limits to align the main body | |
| 1699 // iterations. | |
| 1700 if( should_align ) | |
| 1701 Unimplemented(); | |
| 1702 | |
| 1703 } else { // Else we have an unchanged counted loop | |
| 1704 if( should_peel ) // Might want to peel but do nothing else | |
| 1705 phase->do_peeling(this,old_new); | |
| 1706 } | |
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1707 return true; |
| 0 | 1708 } |
| 1709 | |
| 1710 | |
| 1711 //============================================================================= | |
| 1712 //------------------------------iteration_split-------------------------------- | |
|
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1713 bool IdealLoopTree::iteration_split( PhaseIdealLoop *phase, Node_List &old_new ) { |
| 0 | 1714 // Recursively iteration split nested loops |
|
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1715 if( _child && !_child->iteration_split( phase, old_new )) |
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1716 return false; |
| 0 | 1717 |
| 1718 // Clean out prior deadwood | |
| 1719 DCE_loop_body(); | |
| 1720 | |
| 1721 | |
| 1722 // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. | |
| 1723 // Replace with a 1-in-10 exit guess. | |
| 1724 if( _parent /*not the root loop*/ && | |
| 1725 !_irreducible && | |
| 1726 // Also ignore the occasional dead backedge | |
| 1727 !tail()->is_top() ) { | |
| 1728 adjust_loop_exit_prob(phase); | |
| 1729 } | |
| 1730 | |
| 1731 | |
| 1732 // Gate unrolling, RCE and peeling efforts. | |
| 1733 if( !_child && // If not an inner loop, do not split | |
| 1734 !_irreducible && | |
|
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1735 _allow_optimizations && |
| 0 | 1736 !tail()->is_top() ) { // Also ignore the occasional dead backedge |
| 1737 if (!_has_call) { | |
| 1172 | 1738 if (!iteration_split_impl( phase, old_new )) { |
| 1739 return false; | |
| 1740 } | |
| 0 | 1741 } else if (policy_unswitching(phase)) { |
| 1742 phase->do_unswitching(this, old_new); | |
| 1743 } | |
| 1744 } | |
| 1745 | |
| 1746 // Minor offset re-organization to remove loop-fallout uses of | |
| 1747 // trip counter. | |
| 1748 if( _head->is_CountedLoop() ) phase->reorg_offsets( this ); | |
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1749 if( _next && !_next->iteration_split( phase, old_new )) |
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1750 return false; |
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1751 return true; |
| 0 | 1752 } |
| 1172 | 1753 |
| 1754 //-------------------------------is_uncommon_trap_proj---------------------------- | |
| 1755 // Return true if proj is the form of "proj->[region->..]call_uct" | |
| 1756 bool PhaseIdealLoop::is_uncommon_trap_proj(ProjNode* proj, bool must_reason_predicate) { | |
| 1757 int path_limit = 10; | |
| 1758 assert(proj, "invalid argument"); | |
| 1759 Node* out = proj; | |
| 1760 for (int ct = 0; ct < path_limit; ct++) { | |
| 1761 out = out->unique_ctrl_out(); | |
| 1762 if (out == NULL || out->is_Root() || out->is_Start()) | |
| 1763 return false; | |
| 1764 if (out->is_CallStaticJava()) { | |
| 1765 int req = out->as_CallStaticJava()->uncommon_trap_request(); | |
| 1766 if (req != 0) { | |
| 1767 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(req); | |
| 1768 if (!must_reason_predicate || reason == Deoptimization::Reason_predicate){ | |
| 1769 return true; | |
| 1770 } | |
| 1771 } | |
| 1772 return false; // don't do further after call | |
| 1773 } | |
| 1774 } | |
| 1775 return false; | |
| 1776 } | |
| 1777 | |
| 1778 //-------------------------------is_uncommon_trap_if_pattern------------------------- | |
| 1779 // Return true for "if(test)-> proj -> ... | |
| 1780 // | | |
| 1781 // V | |
| 1782 // other_proj->[region->..]call_uct" | |
| 1783 // | |
| 1784 // "must_reason_predicate" means the uct reason must be Reason_predicate | |
| 1785 bool PhaseIdealLoop::is_uncommon_trap_if_pattern(ProjNode *proj, bool must_reason_predicate) { | |
| 1786 Node *in0 = proj->in(0); | |
| 1787 if (!in0->is_If()) return false; | |
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1788 // Variation of a dead If node. |
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1789 if (in0->outcnt() < 2) return false; |
| 1172 | 1790 IfNode* iff = in0->as_If(); |
| 1791 | |
| 1792 // we need "If(Conv2B(Opaque1(...)))" pattern for must_reason_predicate | |
| 1793 if (must_reason_predicate) { | |
| 1794 if (iff->in(1)->Opcode() != Op_Conv2B || | |
| 1795 iff->in(1)->in(1)->Opcode() != Op_Opaque1) { | |
| 1796 return false; | |
| 1797 } | |
| 1798 } | |
| 1799 | |
| 1800 ProjNode* other_proj = iff->proj_out(1-proj->_con)->as_Proj(); | |
| 1801 return is_uncommon_trap_proj(other_proj, must_reason_predicate); | |
| 1802 } | |
| 1803 | |
| 1804 //------------------------------create_new_if_for_predicate------------------------ | |
| 1805 // create a new if above the uct_if_pattern for the predicate to be promoted. | |
| 1806 // | |
| 1807 // before after | |
| 1808 // ---------- ---------- | |
| 1809 // ctrl ctrl | |
| 1810 // | | | |
| 1811 // | | | |
| 1812 // v v | |
| 1813 // iff new_iff | |
| 1814 // / \ / \ | |
| 1815 // / \ / \ | |
| 1816 // v v v v | |
| 1817 // uncommon_proj cont_proj if_uct if_cont | |
| 1818 // \ | | | | | |
| 1819 // \ | | | | | |
| 1820 // v v v | v | |
| 1821 // rgn loop | iff | |
| 1822 // | | / \ | |
| 1823 // | | / \ | |
| 1824 // v | v v | |
| 1825 // uncommon_trap | uncommon_proj cont_proj | |
| 1826 // \ \ | | | |
| 1827 // \ \ | | | |
| 1828 // v v v v | |
| 1829 // rgn loop | |
| 1830 // | | |
| 1831 // | | |
| 1832 // v | |
| 1833 // uncommon_trap | |
| 1834 // | |
| 1835 // | |
| 1836 // We will create a region to guard the uct call if there is no one there. | |
| 1837 // The true projecttion (if_cont) of the new_iff is returned. | |
| 1838 ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj) { | |
| 1839 assert(is_uncommon_trap_if_pattern(cont_proj, true), "must be a uct if pattern!"); | |
| 1840 IfNode* iff = cont_proj->in(0)->as_If(); | |
| 1841 | |
| 1842 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); | |
| 1843 Node *rgn = uncommon_proj->unique_ctrl_out(); | |
| 1844 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
| 1845 | |
| 1846 if (!rgn->is_Region()) { // create a region to guard the call | |
| 1847 assert(rgn->is_Call(), "must be call uct"); | |
| 1848 CallNode* call = rgn->as_Call(); | |
| 1849 rgn = new (C, 1) RegionNode(1); | |
| 1850 _igvn.set_type(rgn, rgn->bottom_type()); | |
| 1851 rgn->add_req(uncommon_proj); | |
| 1852 set_idom(rgn, idom(uncommon_proj), dom_depth(uncommon_proj)+1); | |
| 1853 _igvn.hash_delete(call); | |
| 1854 call->set_req(0, rgn); | |
| 1855 } | |
| 1856 | |
| 1857 // Create new_iff | |
| 1858 uint iffdd = dom_depth(iff); | |
| 1859 IdealLoopTree* lp = get_loop(iff); | |
| 1860 IfNode *new_iff = new (C, 2) IfNode(iff->in(0), NULL, iff->_prob, iff->_fcnt); | |
| 1861 register_node(new_iff, lp, idom(iff), iffdd); | |
| 1862 Node *if_cont = new (C, 1) IfTrueNode(new_iff); | |
| 1863 Node *if_uct = new (C, 1) IfFalseNode(new_iff); | |
| 1864 if (cont_proj->is_IfFalse()) { | |
| 1865 // Swap | |
| 1866 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; | |
| 1867 } | |
| 1868 register_node(if_cont, lp, new_iff, iffdd); | |
| 1869 register_node(if_uct, get_loop(rgn), new_iff, iffdd); | |
| 1870 | |
| 1871 // if_cont to iff | |
| 1872 _igvn.hash_delete(iff); | |
| 1873 iff->set_req(0, if_cont); | |
| 1874 set_idom(iff, if_cont, dom_depth(iff)); | |
| 1875 | |
| 1876 // if_uct to rgn | |
| 1877 _igvn.hash_delete(rgn); | |
| 1878 rgn->add_req(if_uct); | |
| 1879 Node* ridom = idom(rgn); | |
| 1880 Node* nrdom = dom_lca(ridom, new_iff); | |
| 1881 set_idom(rgn, nrdom, dom_depth(rgn)); | |
| 1882 | |
| 1883 // rgn must have no phis | |
| 1884 assert(!rgn->as_Region()->has_phi(), "region must have no phis"); | |
| 1885 | |
| 1886 return if_cont->as_Proj(); | |
| 1887 } | |
| 1888 | |
| 1889 //------------------------------find_predicate_insertion_point-------------------------- | |
| 1890 // Find a good location to insert a predicate | |
| 1891 ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c) { | |
| 1892 if (start_c == C->root() || !start_c->is_Proj()) | |
| 1893 return NULL; | |
| 1894 if (is_uncommon_trap_if_pattern(start_c->as_Proj(), true/*Reason_Predicate*/)) { | |
| 1895 return start_c->as_Proj(); | |
| 1896 } | |
| 1897 return NULL; | |
| 1898 } | |
| 1899 | |
| 1900 //------------------------------Invariance----------------------------------- | |
| 1901 // Helper class for loop_predication_impl to compute invariance on the fly and | |
| 1902 // clone invariants. | |
| 1903 class Invariance : public StackObj { | |
| 1904 VectorSet _visited, _invariant; | |
| 1905 Node_Stack _stack; | |
| 1906 VectorSet _clone_visited; | |
| 1907 Node_List _old_new; // map of old to new (clone) | |
| 1908 IdealLoopTree* _lpt; | |
| 1909 PhaseIdealLoop* _phase; | |
| 1910 | |
| 1911 // Helper function to set up the invariance for invariance computation | |
| 1912 // If n is a known invariant, set up directly. Otherwise, look up the | |
| 1913 // the possibility to push n onto the stack for further processing. | |
| 1914 void visit(Node* use, Node* n) { | |
| 1915 if (_lpt->is_invariant(n)) { // known invariant | |
| 1916 _invariant.set(n->_idx); | |
| 1917 } else if (!n->is_CFG()) { | |
| 1918 Node *n_ctrl = _phase->ctrl_or_self(n); | |
| 1919 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG | |
| 1920 if (_phase->is_dominator(n_ctrl, u_ctrl)) { | |
| 1921 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
| 1922 } | |
| 1923 } | |
| 1924 } | |
| 1925 | |
| 1926 // Compute invariance for "the_node" and (possibly) all its inputs recursively | |
| 1927 // on the fly | |
| 1928 void compute_invariance(Node* n) { | |
| 1929 assert(_visited.test(n->_idx), "must be"); | |
| 1930 visit(n, n); | |
| 1931 while (_stack.is_nonempty()) { | |
| 1932 Node* n = _stack.node(); | |
| 1933 uint idx = _stack.index(); | |
| 1934 if (idx == n->req()) { // all inputs are processed | |
| 1935 _stack.pop(); | |
| 1936 // n is invariant if it's inputs are all invariant | |
| 1937 bool all_inputs_invariant = true; | |
| 1938 for (uint i = 0; i < n->req(); i++) { | |
| 1939 Node* in = n->in(i); | |
| 1940 if (in == NULL) continue; | |
| 1941 assert(_visited.test(in->_idx), "must have visited input"); | |
| 1942 if (!_invariant.test(in->_idx)) { // bad guy | |
| 1943 all_inputs_invariant = false; | |
| 1944 break; | |
| 1945 } | |
| 1946 } | |
| 1947 if (all_inputs_invariant) { | |
| 1948 _invariant.set(n->_idx); // I am a invariant too | |
| 1949 } | |
| 1950 } else { // process next input | |
| 1951 _stack.set_index(idx + 1); | |
| 1952 Node* m = n->in(idx); | |
| 1953 if (m != NULL && !_visited.test_set(m->_idx)) { | |
| 1954 visit(n, m); | |
| 1955 } | |
| 1956 } | |
| 1957 } | |
| 1958 } | |
| 1959 | |
| 1960 // Helper function to set up _old_new map for clone_nodes. | |
| 1961 // If n is a known invariant, set up directly ("clone" of n == n). | |
| 1962 // Otherwise, push n onto the stack for real cloning. | |
| 1963 void clone_visit(Node* n) { | |
| 1964 assert(_invariant.test(n->_idx), "must be invariant"); | |
| 1965 if (_lpt->is_invariant(n)) { // known invariant | |
| 1966 _old_new.map(n->_idx, n); | |
| 1967 } else{ // to be cloned | |
| 1968 assert (!n->is_CFG(), "should not see CFG here"); | |
| 1969 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
| 1970 } | |
| 1971 } | |
| 1972 | |
| 1973 // Clone "n" and (possibly) all its inputs recursively | |
| 1974 void clone_nodes(Node* n, Node* ctrl) { | |
| 1975 clone_visit(n); | |
| 1976 while (_stack.is_nonempty()) { | |
| 1977 Node* n = _stack.node(); | |
| 1978 uint idx = _stack.index(); | |
| 1979 if (idx == n->req()) { // all inputs processed, clone n! | |
| 1980 _stack.pop(); | |
| 1981 // clone invariant node | |
| 1982 Node* n_cl = n->clone(); | |
| 1983 _old_new.map(n->_idx, n_cl); | |
| 1984 _phase->register_new_node(n_cl, ctrl); | |
| 1985 for (uint i = 0; i < n->req(); i++) { | |
| 1986 Node* in = n_cl->in(i); | |
| 1987 if (in == NULL) continue; | |
| 1988 n_cl->set_req(i, _old_new[in->_idx]); | |
| 1989 } | |
| 1990 } else { // process next input | |
| 1991 _stack.set_index(idx + 1); | |
| 1992 Node* m = n->in(idx); | |
| 1993 if (m != NULL && !_clone_visited.test_set(m->_idx)) { | |
| 1994 clone_visit(m); // visit the input | |
| 1995 } | |
| 1996 } | |
| 1997 } | |
| 1998 } | |
| 1999 | |
| 2000 public: | |
| 2001 Invariance(Arena* area, IdealLoopTree* lpt) : | |
| 2002 _lpt(lpt), _phase(lpt->_phase), | |
| 2003 _visited(area), _invariant(area), _stack(area, 10 /* guess */), | |
| 2004 _clone_visited(area), _old_new(area) | |
| 2005 {} | |
| 2006 | |
| 2007 // Map old to n for invariance computation and clone | |
| 2008 void map_ctrl(Node* old, Node* n) { | |
| 2009 assert(old->is_CFG() && n->is_CFG(), "must be"); | |
| 2010 _old_new.map(old->_idx, n); // "clone" of old is n | |
| 2011 _invariant.set(old->_idx); // old is invariant | |
| 2012 _clone_visited.set(old->_idx); | |
| 2013 } | |
| 2014 | |
| 2015 // Driver function to compute invariance | |
| 2016 bool is_invariant(Node* n) { | |
| 2017 if (!_visited.test_set(n->_idx)) | |
| 2018 compute_invariance(n); | |
| 2019 return (_invariant.test(n->_idx) != 0); | |
| 2020 } | |
| 2021 | |
| 2022 // Driver function to clone invariant | |
| 2023 Node* clone(Node* n, Node* ctrl) { | |
| 2024 assert(ctrl->is_CFG(), "must be"); | |
| 2025 assert(_invariant.test(n->_idx), "must be an invariant"); | |
| 2026 if (!_clone_visited.test(n->_idx)) | |
| 2027 clone_nodes(n, ctrl); | |
| 2028 return _old_new[n->_idx]; | |
| 2029 } | |
| 2030 }; | |
| 2031 | |
| 2032 //------------------------------is_range_check_if ----------------------------------- | |
| 2033 // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format | |
| 2034 // Note: this function is particularly designed for loop predication. We require load_range | |
| 2035 // and offset to be loop invariant computed on the fly by "invar" | |
| 2036 bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { | |
| 2037 if (!is_loop_exit(iff)) { | |
| 2038 return false; | |
| 2039 } | |
| 2040 if (!iff->in(1)->is_Bool()) { | |
| 2041 return false; | |
| 2042 } | |
| 2043 const BoolNode *bol = iff->in(1)->as_Bool(); | |
| 2044 if (bol->_test._test != BoolTest::lt) { | |
| 2045 return false; | |
| 2046 } | |
| 2047 if (!bol->in(1)->is_Cmp()) { | |
| 2048 return false; | |
| 2049 } | |
| 2050 const CmpNode *cmp = bol->in(1)->as_Cmp(); | |
| 2051 if (cmp->Opcode() != Op_CmpU ) { | |
| 2052 return false; | |
| 2053 } | |
| 2054 if (cmp->in(2)->Opcode() != Op_LoadRange) { | |
| 2055 return false; | |
| 2056 } | |
| 2057 LoadRangeNode* lr = (LoadRangeNode*)cmp->in(2); | |
| 2058 if (!invar.is_invariant(lr)) { // loadRange must be invariant | |
| 2059 return false; | |
| 2060 } | |
| 2061 Node *iv = _head->as_CountedLoop()->phi(); | |
| 2062 int scale = 0; | |
| 2063 Node *offset = NULL; | |
| 2064 if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { | |
| 2065 return false; | |
| 2066 } | |
| 2067 if(offset && !invar.is_invariant(offset)) { // offset must be invariant | |
| 2068 return false; | |
| 2069 } | |
| 2070 return true; | |
| 2071 } | |
| 2072 | |
| 2073 //------------------------------rc_predicate----------------------------------- | |
| 2074 // Create a range check predicate | |
| 2075 // | |
| 2076 // for (i = init; i < limit; i += stride) { | |
| 2077 // a[scale*i+offset] | |
| 2078 // } | |
| 2079 // | |
| 2080 // Compute max(scale*i + offset) for init <= i < limit and build the predicate | |
| 2081 // as "max(scale*i + offset) u< a.length". | |
| 2082 // | |
| 2083 // There are two cases for max(scale*i + offset): | |
| 2084 // (1) stride*scale > 0 | |
| 2085 // max(scale*i + offset) = scale*(limit-stride) + offset | |
| 2086 // (2) stride*scale < 0 | |
| 2087 // max(scale*i + offset) = scale*init + offset | |
| 2088 BoolNode* PhaseIdealLoop::rc_predicate(Node* ctrl, | |
| 2089 int scale, Node* offset, | |
| 2090 Node* init, Node* limit, Node* stride, | |
|
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2091 Node* range, bool upper) { |
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2092 DEBUG_ONLY(ttyLocker ttyl); |
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2093 if (TraceLoopPredicate) tty->print("rc_predicate "); |
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2094 |
| 1172 | 2095 Node* max_idx_expr = init; |
| 2096 int stride_con = stride->get_int(); | |
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2097 if ((stride_con > 0) == (scale > 0) == upper) { |
| 1172 | 2098 max_idx_expr = new (C, 3) SubINode(limit, stride); |
| 2099 register_new_node(max_idx_expr, ctrl); | |
|
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2100 if (TraceLoopPredicate) tty->print("(limit - stride) "); |
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2101 } else { |
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2102 if (TraceLoopPredicate) tty->print("init "); |
| 1172 | 2103 } |
| 2104 | |
| 2105 if (scale != 1) { | |
| 2106 ConNode* con_scale = _igvn.intcon(scale); | |
| 2107 max_idx_expr = new (C, 3) MulINode(max_idx_expr, con_scale); | |
| 2108 register_new_node(max_idx_expr, ctrl); | |
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2109 if (TraceLoopPredicate) tty->print("* %d ", scale); |
| 1172 | 2110 } |
| 2111 | |
| 2112 if (offset && (!offset->is_Con() || offset->get_int() != 0)){ | |
| 2113 max_idx_expr = new (C, 3) AddINode(max_idx_expr, offset); | |
| 2114 register_new_node(max_idx_expr, ctrl); | |
|
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2115 if (TraceLoopPredicate) |
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2116 if (offset->is_Con()) tty->print("+ %d ", offset->get_int()); |
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2117 else tty->print("+ offset "); |
| 1172 | 2118 } |
| 2119 | |
| 2120 CmpUNode* cmp = new (C, 3) CmpUNode(max_idx_expr, range); | |
| 2121 register_new_node(cmp, ctrl); | |
| 2122 BoolNode* bol = new (C, 2) BoolNode(cmp, BoolTest::lt); | |
| 2123 register_new_node(bol, ctrl); | |
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|
2124 |
|
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|
2125 if (TraceLoopPredicate) tty->print_cr("<u range"); |
| 1172 | 2126 return bol; |
| 2127 } | |
| 2128 | |
| 2129 //------------------------------ loop_predication_impl-------------------------- | |
| 2130 // Insert loop predicates for null checks and range checks | |
| 2131 bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { | |
| 2132 if (!UseLoopPredicate) return false; | |
| 2133 | |
| 1275 | 2134 if (!loop->_head->is_Loop()) { |
| 2135 // Could be a simple region when irreducible loops are present. | |
| 2136 return false; | |
| 2137 } | |
| 2138 | |
| 2139 CountedLoopNode *cl = NULL; | |
| 2140 if (loop->_head->is_CountedLoop()) { | |
| 2141 cl = loop->_head->as_CountedLoop(); | |
| 2142 // do nothing for iteration-splitted loops | |
| 2143 if (!cl->is_normal_loop()) return false; | |
| 2144 } | |
| 2145 | |
| 1172 | 2146 // Too many traps seen? |
| 2147 bool tmt = C->too_many_traps(C->method(), 0, Deoptimization::Reason_predicate); | |
| 2148 int tc = C->trap_count(Deoptimization::Reason_predicate); | |
| 2149 if (tmt || tc > 0) { | |
| 2150 if (TraceLoopPredicate) { | |
| 2151 tty->print_cr("too many predicate traps: %d", tc); | |
| 2152 C->method()->print(); // which method has too many predicate traps | |
| 2153 tty->print_cr(""); | |
| 2154 } | |
| 2155 return false; | |
| 2156 } | |
| 2157 | |
| 2158 LoopNode *lpn = loop->_head->as_Loop(); | |
| 2159 Node* entry = lpn->in(LoopNode::EntryControl); | |
| 2160 | |
| 2161 ProjNode *predicate_proj = find_predicate_insertion_point(entry); | |
| 2162 if (!predicate_proj){ | |
| 2163 #ifndef PRODUCT | |
| 2164 if (TraceLoopPredicate) { | |
| 2165 tty->print("missing predicate:"); | |
| 2166 loop->dump_head(); | |
| 2167 } | |
| 2168 #endif | |
| 2169 return false; | |
| 2170 } | |
| 2171 | |
| 2172 ConNode* zero = _igvn.intcon(0); | |
| 2173 set_ctrl(zero, C->root()); | |
| 2174 Node *cond_false = new (C, 2) Conv2BNode(zero); | |
| 2175 register_new_node(cond_false, C->root()); | |
| 2176 ConNode* one = _igvn.intcon(1); | |
| 2177 set_ctrl(one, C->root()); | |
| 2178 Node *cond_true = new (C, 2) Conv2BNode(one); | |
| 2179 register_new_node(cond_true, C->root()); | |
| 2180 | |
| 2181 ResourceArea *area = Thread::current()->resource_area(); | |
| 2182 Invariance invar(area, loop); | |
| 2183 | |
| 2184 // Create list of if-projs such that a newer proj dominates all older | |
| 2185 // projs in the list, and they all dominate loop->tail() | |
| 2186 Node_List if_proj_list(area); | |
| 2187 LoopNode *head = loop->_head->as_Loop(); | |
| 2188 Node *current_proj = loop->tail(); //start from tail | |
| 2189 while ( current_proj != head ) { | |
| 2190 if (loop == get_loop(current_proj) && // still in the loop ? | |
| 2191 current_proj->is_Proj() && // is a projection ? | |
| 2192 current_proj->in(0)->Opcode() == Op_If) { // is a if projection ? | |
| 2193 if_proj_list.push(current_proj); | |
| 2194 } | |
| 2195 current_proj = idom(current_proj); | |
| 2196 } | |
| 2197 | |
| 2198 bool hoisted = false; // true if at least one proj is promoted | |
| 2199 while (if_proj_list.size() > 0) { | |
| 2200 // Following are changed to nonnull when a predicate can be hoisted | |
| 2201 ProjNode* new_predicate_proj = NULL; | |
| 2202 | |
| 2203 ProjNode* proj = if_proj_list.pop()->as_Proj(); | |
| 2204 IfNode* iff = proj->in(0)->as_If(); | |
| 2205 | |
| 2206 if (!is_uncommon_trap_if_pattern(proj)) { | |
| 2207 if (loop->is_loop_exit(iff)) { | |
| 2208 // stop processing the remaining projs in the list because the execution of them | |
| 2209 // depends on the condition of "iff" (iff->in(1)). | |
| 2210 break; | |
| 2211 } else { | |
| 2212 // Both arms are inside the loop. There are two cases: | |
| 2213 // (1) there is one backward branch. In this case, any remaining proj | |
| 2214 // in the if_proj list post-dominates "iff". So, the condition of "iff" | |
| 2215 // does not determine the execution the remining projs directly, and we | |
| 2216 // can safely continue. | |
| 2217 // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" | |
| 2218 // does not dominate loop->tail(), so it can not be in the if_proj list. | |
| 2219 continue; | |
| 2220 } | |
| 2221 } | |
| 2222 | |
| 2223 Node* test = iff->in(1); | |
| 2224 if (!test->is_Bool()){ //Conv2B, ... | |
| 2225 continue; | |
| 2226 } | |
| 2227 BoolNode* bol = test->as_Bool(); | |
| 2228 if (invar.is_invariant(bol)) { | |
| 2229 // Invariant test | |
| 2230 new_predicate_proj = create_new_if_for_predicate(predicate_proj); | |
| 2231 Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); | |
|
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|
2232 BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); |
|
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|
2233 |
|
c047da02984c
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|
2234 // Negate test if necessary |
|
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|
2235 bool negated = false; |
|
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|
2236 if (proj->_con != predicate_proj->_con) { |
|
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|
2237 new_predicate_bol = new (C, 2) BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); |
|
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|
2238 register_new_node(new_predicate_bol, ctrl); |
|
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|
2239 negated = true; |
|
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|
2240 } |
|
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|
2241 IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If(); |
|
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|
2242 _igvn.hash_delete(new_predicate_iff); |
|
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|
2243 new_predicate_iff->set_req(1, new_predicate_bol); |
|
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|
2244 if (TraceLoopPredicate) tty->print_cr("invariant if%s: %d", negated ? " negated" : "", new_predicate_iff->_idx); |
|
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|
2245 |
| 1172 | 2246 } else if (cl != NULL && loop->is_range_check_if(iff, this, invar)) { |
|
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|
2247 assert(proj->_con == predicate_proj->_con, "must match"); |
|
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|
2248 |
|
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|
2249 // Range check for counted loops |
| 1172 | 2250 const Node* cmp = bol->in(1)->as_Cmp(); |
| 2251 Node* idx = cmp->in(1); | |
| 2252 assert(!invar.is_invariant(idx), "index is variant"); | |
| 2253 assert(cmp->in(2)->Opcode() == Op_LoadRange, "must be"); | |
|
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|
2254 Node* ld_rng = cmp->in(2); // LoadRangeNode |
| 1172 | 2255 assert(invar.is_invariant(ld_rng), "load range must be invariant"); |
| 2256 int scale = 1; | |
| 2257 Node* offset = zero; | |
| 2258 bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); | |
| 2259 assert(ok, "must be index expression"); | |
|
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|
2260 |
|
c047da02984c
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|
2261 Node* init = cl->init_trip(); |
|
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|
2262 Node* limit = cl->limit(); |
|
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|
2263 Node* stride = cl->stride(); |
|
c047da02984c
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|
2264 |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2265 // Build if's for the upper and lower bound tests. The |
|
c047da02984c
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|
2266 // lower_bound test will dominate the upper bound test and all |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2267 // cloned or created nodes will use the lower bound test as |
|
c047da02984c
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|
2268 // their declared control. |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2269 ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj); |
|
c047da02984c
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|
2270 ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj); |
|
c047da02984c
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|
2271 assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate"); |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2272 Node *ctrl = lower_bound_proj->in(0)->as_If()->in(0); |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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changeset
|
2273 |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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changeset
|
2274 // Perform cloning to keep Invariance state correct since the |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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changeset
|
2275 // late schedule will place invariant things in the loop. |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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parents:
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changeset
|
2276 ld_rng = invar.clone(ld_rng, ctrl); |
| 1172 | 2277 if (offset && offset != zero) { |
| 2278 assert(invar.is_invariant(offset), "offset must be loop invariant"); | |
| 2279 offset = invar.clone(offset, ctrl); | |
| 2280 } | |
|
1303
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changeset
|
2281 |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2282 // Test the lower bound |
|
c047da02984c
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|
2283 Node* lower_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, ld_rng, false); |
|
c047da02984c
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|
2284 IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If(); |
|
c047da02984c
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changeset
|
2285 _igvn.hash_delete(lower_bound_iff); |
|
c047da02984c
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|
2286 lower_bound_iff->set_req(1, lower_bound_bol); |
|
c047da02984c
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|
2287 if (TraceLoopPredicate) tty->print_cr("lower bound check if: %d", lower_bound_iff->_idx); |
| 1172 | 2288 |
|
1303
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|
2289 // Test the upper bound |
|
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|
2290 Node* upper_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, ld_rng, true); |
|
c047da02984c
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|
2291 IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If(); |
|
c047da02984c
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|
2292 _igvn.hash_delete(upper_bound_iff); |
|
c047da02984c
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|
2293 upper_bound_iff->set_req(1, upper_bound_bol); |
|
c047da02984c
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changeset
|
2294 if (TraceLoopPredicate) tty->print_cr("upper bound check if: %d", lower_bound_iff->_idx); |
|
c047da02984c
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never
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|
2295 |
|
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2296 // Fall through into rest of the clean up code which will move |
|
c047da02984c
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|
2297 // any dependent nodes onto the upper bound test. |
|
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changeset
|
2298 new_predicate_proj = upper_bound_proj; |
|
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|
2299 } else { |
| 1172 | 2300 // The other proj of the "iff" is a uncommon trap projection, and we can assume |
| 2301 // the other proj will not be executed ("executed" means uct raised). | |
| 2302 continue; | |
|
1303
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|
2303 } |
| 1172 | 2304 |
|
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|
2305 // Success - attach condition (new_predicate_bol) to predicate if |
|
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changeset
|
2306 invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate |
| 1172 | 2307 |
|
1303
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|
2308 // Eliminate the old if in the loop body |
|
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|
2309 _igvn.hash_delete(iff); |
|
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|
2310 iff->set_req(1, proj->is_IfFalse() ? cond_false : cond_true); |
| 1172 | 2311 |
|
1303
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changeset
|
2312 Node* ctrl = new_predicate_proj; // new control |
|
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|
2313 ProjNode* dp = proj; // old control |
|
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2314 assert(get_loop(dp) == loop, "guaranteed at the time of collecting proj"); |
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2315 // Find nodes (depends only on the test) off the surviving projection; |
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2316 // move them outside the loop with the control of proj_clone |
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2317 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { |
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2318 Node* cd = dp->fast_out(i); // Control-dependent node |
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2319 if (cd->depends_only_on_test()) { |
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2320 assert(cd->in(0) == dp, ""); |
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2321 _igvn.hash_delete(cd); |
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2322 cd->set_req(0, ctrl); // ctrl, not NULL |
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2323 set_early_ctrl(cd); |
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2324 _igvn._worklist.push(cd); |
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2325 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); |
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2326 if (new_loop != loop) { |
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2327 if (!loop->_child) loop->_body.yank(cd); |
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2328 if (!new_loop->_child ) new_loop->_body.push(cd); |
| 1172 | 2329 } |
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1303
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2330 --i; |
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2331 --imax; |
| 1172 | 2332 } |
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1303
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2333 } |
| 1172 | 2334 |
|
1303
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2335 hoisted = true; |
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2336 C->set_major_progress(); |
| 1172 | 2337 } // end while |
| 2338 | |
| 2339 #ifndef PRODUCT | |
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2340 // report that the loop predication has been actually performed |
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2341 // for this loop |
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2342 if (TraceLoopPredicate && hoisted) { |
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2343 tty->print("Loop Predication Performed:"); |
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2344 loop->dump_head(); |
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2345 } |
| 1172 | 2346 #endif |
| 2347 | |
| 2348 return hoisted; | |
| 2349 } | |
| 2350 | |
| 2351 //------------------------------loop_predication-------------------------------- | |
| 2352 // driver routine for loop predication optimization | |
| 2353 bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { | |
| 2354 bool hoisted = false; | |
| 2355 // Recursively promote predicates | |
| 2356 if ( _child ) { | |
| 2357 hoisted = _child->loop_predication( phase); | |
| 2358 } | |
| 2359 | |
| 2360 // self | |
| 2361 if (!_irreducible && !tail()->is_top()) { | |
| 2362 hoisted |= phase->loop_predication_impl(this); | |
| 2363 } | |
| 2364 | |
| 2365 if ( _next ) { //sibling | |
| 2366 hoisted |= _next->loop_predication( phase); | |
| 2367 } | |
| 2368 | |
| 2369 return hoisted; | |
| 2370 } |