1 /* 2 * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "gc/shared/barrierSet.hpp" 27 #include "gc/shared/c2/barrierSetC2.hpp" 28 #include "memory/allocation.inline.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "opto/addnode.hpp" 31 #include "opto/callnode.hpp" 32 #include "opto/castnode.hpp" 33 #include "opto/connode.hpp" 34 #include "opto/castnode.hpp" 35 #include "opto/divnode.hpp" 36 #include "opto/loopnode.hpp" 37 #include "opto/matcher.hpp" 38 #include "opto/mulnode.hpp" 39 #include "opto/movenode.hpp" 40 #include "opto/opaquenode.hpp" 41 #include "opto/rootnode.hpp" 42 #include "opto/subnode.hpp" 43 #include "opto/subtypenode.hpp" 44 #include "opto/superword.hpp" 45 #include "opto/vectornode.hpp" 46 #include "utilities/macros.hpp" 47 48 //============================================================================= 49 //------------------------------split_thru_phi--------------------------------- 50 // Split Node 'n' through merge point if there is enough win. 51 Node* PhaseIdealLoop::split_thru_phi(Node* n, Node* region, int policy) { 52 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { 53 // ConvI2L may have type information on it which is unsafe to push up 54 // so disable this for now 55 return nullptr; 56 } 57 58 // Splitting range check CastIIs through a loop induction Phi can 59 // cause new Phis to be created that are left unrelated to the loop 60 // induction Phi and prevent optimizations (vectorization) 61 if (n->Opcode() == Op_CastII && region->is_CountedLoop() && 62 n->in(1) == region->as_CountedLoop()->phi()) { 63 return nullptr; 64 } 65 66 if (cannot_split_division(n, region)) { 67 return nullptr; 68 } 69 70 int wins = 0; 71 assert(!n->is_CFG(), ""); 72 assert(region->is_Region(), ""); 73 74 const Type* type = n->bottom_type(); 75 const TypeOopPtr* t_oop = _igvn.type(n)->isa_oopptr(); 76 Node* phi; 77 if (t_oop != nullptr && t_oop->is_known_instance_field()) { 78 int iid = t_oop->instance_id(); 79 int index = C->get_alias_index(t_oop); 80 int offset = t_oop->offset(); 81 phi = new PhiNode(region, type, nullptr, iid, index, offset); 82 } else { 83 phi = PhiNode::make_blank(region, n); 84 } 85 uint old_unique = C->unique(); 86 for (uint i = 1; i < region->req(); i++) { 87 Node* x; 88 Node* the_clone = nullptr; 89 if (region->in(i) == C->top()) { 90 x = C->top(); // Dead path? Use a dead data op 91 } else { 92 x = n->clone(); // Else clone up the data op 93 the_clone = x; // Remember for possible deletion. 94 // Alter data node to use pre-phi inputs 95 if (n->in(0) == region) 96 x->set_req( 0, region->in(i) ); 97 for (uint j = 1; j < n->req(); j++) { 98 Node* in = n->in(j); 99 if (in->is_Phi() && in->in(0) == region) 100 x->set_req(j, in->in(i)); // Use pre-Phi input for the clone 101 } 102 } 103 // Check for a 'win' on some paths 104 const Type* t = x->Value(&_igvn); 105 106 bool singleton = t->singleton(); 107 108 // A TOP singleton indicates that there are no possible values incoming 109 // along a particular edge. In most cases, this is OK, and the Phi will 110 // be eliminated later in an Ideal call. However, we can't allow this to 111 // happen if the singleton occurs on loop entry, as the elimination of 112 // the PhiNode may cause the resulting node to migrate back to a previous 113 // loop iteration. 114 if (singleton && t == Type::TOP) { 115 // Is_Loop() == false does not confirm the absence of a loop (e.g., an 116 // irreducible loop may not be indicated by an affirmative is_Loop()); 117 // therefore, the only top we can split thru a phi is on a backedge of 118 // a loop. 119 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); 120 } 121 122 if (singleton) { 123 wins++; 124 x = ((PhaseGVN&)_igvn).makecon(t); 125 } else { 126 // We now call Identity to try to simplify the cloned node. 127 // Note that some Identity methods call phase->type(this). 128 // Make sure that the type array is big enough for 129 // our new node, even though we may throw the node away. 130 // (Note: This tweaking with igvn only works because x is a new node.) 131 _igvn.set_type(x, t); 132 // If x is a TypeNode, capture any more-precise type permanently into Node 133 // otherwise it will be not updated during igvn->transform since 134 // igvn->type(x) is set to x->Value() already. 135 x->raise_bottom_type(t); 136 Node* y = x->Identity(&_igvn); 137 if (y != x) { 138 wins++; 139 x = y; 140 } else { 141 y = _igvn.hash_find(x); 142 if (y == nullptr) { 143 y = similar_subtype_check(x, region->in(i)); 144 } 145 if (y) { 146 wins++; 147 x = y; 148 } else { 149 // Else x is a new node we are keeping 150 // We do not need register_new_node_with_optimizer 151 // because set_type has already been called. 152 _igvn._worklist.push(x); 153 } 154 } 155 } 156 157 phi->set_req( i, x ); 158 159 if (the_clone == nullptr) { 160 continue; 161 } 162 163 if (the_clone != x) { 164 _igvn.remove_dead_node(the_clone); 165 } else if (region->is_Loop() && i == LoopNode::LoopBackControl && 166 n->is_Load() && can_move_to_inner_loop(n, region->as_Loop(), x)) { 167 // it is not a win if 'x' moved from an outer to an inner loop 168 // this edge case can only happen for Load nodes 169 wins = 0; 170 break; 171 } 172 } 173 // Too few wins? 174 if (wins <= policy) { 175 _igvn.remove_dead_node(phi); 176 return nullptr; 177 } 178 179 // Record Phi 180 register_new_node( phi, region ); 181 182 for (uint i2 = 1; i2 < phi->req(); i2++) { 183 Node *x = phi->in(i2); 184 // If we commoned up the cloned 'x' with another existing Node, 185 // the existing Node picks up a new use. We need to make the 186 // existing Node occur higher up so it dominates its uses. 187 Node *old_ctrl; 188 IdealLoopTree *old_loop; 189 190 if (x->is_Con()) { 191 // Constant's control is always root. 192 set_ctrl(x, C->root()); 193 continue; 194 } 195 // The occasional new node 196 if (x->_idx >= old_unique) { // Found a new, unplaced node? 197 old_ctrl = nullptr; 198 old_loop = nullptr; // Not in any prior loop 199 } else { 200 old_ctrl = get_ctrl(x); 201 old_loop = get_loop(old_ctrl); // Get prior loop 202 } 203 // New late point must dominate new use 204 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2)); 205 if (new_ctrl == old_ctrl) // Nothing is changed 206 continue; 207 208 IdealLoopTree *new_loop = get_loop(new_ctrl); 209 210 // Don't move x into a loop if its uses are 211 // outside of loop. Otherwise x will be cloned 212 // for each use outside of this loop. 213 IdealLoopTree *use_loop = get_loop(region); 214 if (!new_loop->is_member(use_loop) && 215 (old_loop == nullptr || !new_loop->is_member(old_loop))) { 216 // Take early control, later control will be recalculated 217 // during next iteration of loop optimizations. 218 new_ctrl = get_early_ctrl(x); 219 new_loop = get_loop(new_ctrl); 220 } 221 // Set new location 222 set_ctrl(x, new_ctrl); 223 // If changing loop bodies, see if we need to collect into new body 224 if (old_loop != new_loop) { 225 if (old_loop && !old_loop->_child) 226 old_loop->_body.yank(x); 227 if (!new_loop->_child) 228 new_loop->_body.push(x); // Collect body info 229 } 230 } 231 232 return phi; 233 } 234 235 // Test whether node 'x' can move into an inner loop relative to node 'n'. 236 // Note: The test is not exact. Returns true if 'x' COULD end up in an inner loop, 237 // BUT it can also return true and 'x' is in the outer loop 238 bool PhaseIdealLoop::can_move_to_inner_loop(Node* n, LoopNode* n_loop, Node* x) { 239 IdealLoopTree* n_loop_tree = get_loop(n_loop); 240 IdealLoopTree* x_loop_tree = get_loop(get_early_ctrl(x)); 241 // x_loop_tree should be outer or same loop as n_loop_tree 242 return !x_loop_tree->is_member(n_loop_tree); 243 } 244 245 // Subtype checks that carry profile data don't common so look for a replacement by following edges 246 Node* PhaseIdealLoop::similar_subtype_check(const Node* x, Node* r_in) { 247 if (x->is_SubTypeCheck()) { 248 Node* in1 = x->in(1); 249 for (DUIterator_Fast imax, i = in1->fast_outs(imax); i < imax; i++) { 250 Node* u = in1->fast_out(i); 251 if (u != x && u->is_SubTypeCheck() && u->in(1) == x->in(1) && u->in(2) == x->in(2)) { 252 for (DUIterator_Fast jmax, j = u->fast_outs(jmax); j < jmax; j++) { 253 Node* bol = u->fast_out(j); 254 for (DUIterator_Fast kmax, k = bol->fast_outs(kmax); k < kmax; k++) { 255 Node* iff = bol->fast_out(k); 256 // Only dominating subtype checks are interesting: otherwise we risk replacing a subtype check by another with 257 // unrelated profile 258 if (iff->is_If() && is_dominator(iff, r_in)) { 259 return u; 260 } 261 } 262 } 263 } 264 } 265 } 266 return nullptr; 267 } 268 269 // Return true if 'n' is a Div or Mod node (without zero check If node which was removed earlier) with a loop phi divisor 270 // of a trip-counted (integer or long) loop with a backedge input that could be zero (include zero in its type range). In 271 // this case, we cannot split the division to the backedge as it could freely float above the loop exit check resulting in 272 // a division by zero. This situation is possible because the type of an increment node of an iv phi (trip-counter) could 273 // include zero while the iv phi does not (see PhiNode::Value() for trip-counted loops where we improve types of iv phis). 274 // We also need to check other loop phis as they could have been created in the same split-if pass when applying 275 // PhaseIdealLoop::split_thru_phi() to split nodes through an iv phi. 276 bool PhaseIdealLoop::cannot_split_division(const Node* n, const Node* region) const { 277 const Type* zero; 278 switch (n->Opcode()) { 279 case Op_DivI: 280 case Op_ModI: 281 zero = TypeInt::ZERO; 282 break; 283 case Op_DivL: 284 case Op_ModL: 285 zero = TypeLong::ZERO; 286 break; 287 default: 288 return false; 289 } 290 291 if (n->in(0) != nullptr) { 292 // Cannot split through phi if Div or Mod node has a control dependency to a zero check. 293 return true; 294 } 295 296 Node* divisor = n->in(2); 297 return is_divisor_counted_loop_phi(divisor, region) && 298 loop_phi_backedge_type_contains_zero(divisor, zero); 299 } 300 301 bool PhaseIdealLoop::is_divisor_counted_loop_phi(const Node* divisor, const Node* loop) { 302 return loop->is_BaseCountedLoop() && divisor->is_Phi() && divisor->in(0) == loop; 303 } 304 305 bool PhaseIdealLoop::loop_phi_backedge_type_contains_zero(const Node* phi_divisor, const Type* zero) const { 306 return _igvn.type(phi_divisor->in(LoopNode::LoopBackControl))->filter_speculative(zero) != Type::TOP; 307 } 308 309 //------------------------------dominated_by------------------------------------ 310 // Replace the dominated test with an obvious true or false. Place it on the 311 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the 312 // live path up to the dominating control. 313 void PhaseIdealLoop::dominated_by(IfProjNode* prevdom, IfNode* iff, bool flip, bool pin_array_access_nodes) { 314 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); } 315 316 // prevdom is the dominating projection of the dominating test. 317 assert(iff->Opcode() == Op_If || 318 iff->Opcode() == Op_CountedLoopEnd || 319 iff->Opcode() == Op_LongCountedLoopEnd || 320 iff->Opcode() == Op_RangeCheck || 321 iff->Opcode() == Op_ParsePredicate, 322 "Check this code when new subtype is added"); 323 324 int pop = prevdom->Opcode(); 325 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); 326 if (flip) { 327 if (pop == Op_IfTrue) 328 pop = Op_IfFalse; 329 else 330 pop = Op_IfTrue; 331 } 332 // 'con' is set to true or false to kill the dominated test. 333 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); 334 set_ctrl(con, C->root()); // Constant gets a new use 335 // Hack the dominated test 336 _igvn.replace_input_of(iff, 1, con); 337 338 // If I don't have a reachable TRUE and FALSE path following the IfNode then 339 // I can assume this path reaches an infinite loop. In this case it's not 340 // important to optimize the data Nodes - either the whole compilation will 341 // be tossed or this path (and all data Nodes) will go dead. 342 if (iff->outcnt() != 2) return; 343 344 // Make control-dependent data Nodes on the live path (path that will remain 345 // once the dominated IF is removed) become control-dependent on the 346 // dominating projection. 347 Node* dp = iff->proj_out_or_null(pop == Op_IfTrue); 348 349 if (dp == nullptr) 350 return; 351 352 IdealLoopTree* old_loop = get_loop(dp); 353 354 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { 355 Node* cd = dp->fast_out(i); // Control-dependent node 356 // Do not rewire Div and Mod nodes which could have a zero divisor to avoid skipping their zero check. 357 if (cd->depends_only_on_test() && _igvn.no_dependent_zero_check(cd)) { 358 assert(cd->in(0) == dp, ""); 359 _igvn.replace_input_of(cd, 0, prevdom); 360 if (pin_array_access_nodes) { 361 // Because of Loop Predication, Loads and range check Cast nodes that are control dependent on this range 362 // check (that is about to be removed) now depend on multiple dominating Hoisted Check Predicates. After the 363 // removal of this range check, these control dependent nodes end up at the lowest/nearest dominating predicate 364 // in the graph. To ensure that these Loads/Casts do not float above any of the dominating checks (even when the 365 // lowest dominating check is later replaced by yet another dominating check), we need to pin them at the lowest 366 // dominating check. 367 Node* clone = cd->pin_array_access_node(); 368 if (clone != nullptr) { 369 clone = _igvn.register_new_node_with_optimizer(clone, cd); 370 _igvn.replace_node(cd, clone); 371 cd = clone; 372 } 373 } 374 set_early_ctrl(cd, false); 375 IdealLoopTree* new_loop = get_loop(get_ctrl(cd)); 376 if (old_loop != new_loop) { 377 if (!old_loop->_child) { 378 old_loop->_body.yank(cd); 379 } 380 if (!new_loop->_child) { 381 new_loop->_body.push(cd); 382 } 383 } 384 --i; 385 --imax; 386 } 387 } 388 } 389 390 //------------------------------has_local_phi_input---------------------------- 391 // Return TRUE if 'n' has Phi inputs from its local block and no other 392 // block-local inputs (all non-local-phi inputs come from earlier blocks) 393 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { 394 Node *n_ctrl = get_ctrl(n); 395 // See if some inputs come from a Phi in this block, or from before 396 // this block. 397 uint i; 398 for( i = 1; i < n->req(); i++ ) { 399 Node *phi = n->in(i); 400 if( phi->is_Phi() && phi->in(0) == n_ctrl ) 401 break; 402 } 403 if( i >= n->req() ) 404 return nullptr; // No Phi inputs; nowhere to clone thru 405 406 // Check for inputs created between 'n' and the Phi input. These 407 // must split as well; they have already been given the chance 408 // (courtesy of a post-order visit) and since they did not we must 409 // recover the 'cost' of splitting them by being very profitable 410 // when splitting 'n'. Since this is unlikely we simply give up. 411 for( i = 1; i < n->req(); i++ ) { 412 Node *m = n->in(i); 413 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { 414 // We allow the special case of AddP's with no local inputs. 415 // This allows us to split-up address expressions. 416 if (m->is_AddP() && 417 get_ctrl(m->in(AddPNode::Base)) != n_ctrl && 418 get_ctrl(m->in(AddPNode::Address)) != n_ctrl && 419 get_ctrl(m->in(AddPNode::Offset)) != n_ctrl) { 420 // Move the AddP up to the dominating point. That's fine because control of m's inputs 421 // must dominate get_ctrl(m) == n_ctrl and we just checked that the input controls are != n_ctrl. 422 Node* c = find_non_split_ctrl(idom(n_ctrl)); 423 if (c->is_OuterStripMinedLoop()) { 424 c->as_Loop()->verify_strip_mined(1); 425 c = c->in(LoopNode::EntryControl); 426 } 427 set_ctrl_and_loop(m, c); 428 continue; 429 } 430 return nullptr; 431 } 432 assert(n->is_Phi() || m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control"); 433 } 434 435 return n_ctrl; 436 } 437 438 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). 439 Node* PhaseIdealLoop::remix_address_expressions_add_left_shift(Node* n, IdealLoopTree* n_loop, Node* n_ctrl, BasicType bt) { 440 assert(bt == T_INT || bt == T_LONG, "only for integers"); 441 int n_op = n->Opcode(); 442 443 if (n_op == Op_LShift(bt)) { 444 // Scale is loop invariant 445 Node* scale = n->in(2); 446 Node* scale_ctrl = get_ctrl(scale); 447 IdealLoopTree* scale_loop = get_loop(scale_ctrl); 448 if (n_loop == scale_loop || !scale_loop->is_member(n_loop)) { 449 return nullptr; 450 } 451 const TypeInt* scale_t = scale->bottom_type()->isa_int(); 452 if (scale_t != nullptr && scale_t->is_con() && scale_t->get_con() >= 16) { 453 return nullptr; // Dont bother with byte/short masking 454 } 455 // Add must vary with loop (else shift would be loop-invariant) 456 Node* add = n->in(1); 457 Node* add_ctrl = get_ctrl(add); 458 IdealLoopTree* add_loop = get_loop(add_ctrl); 459 if (n_loop != add_loop) { 460 return nullptr; // happens w/ evil ZKM loops 461 } 462 463 // Convert I-V into I+ (0-V); same for V-I 464 if (add->Opcode() == Op_Sub(bt) && 465 _igvn.type(add->in(1)) != TypeInteger::zero(bt)) { 466 assert(add->Opcode() == Op_SubI || add->Opcode() == Op_SubL, ""); 467 Node* zero = _igvn.integercon(0, bt); 468 set_ctrl(zero, C->root()); 469 Node* neg = SubNode::make(zero, add->in(2), bt); 470 register_new_node(neg, get_ctrl(add->in(2))); 471 add = AddNode::make(add->in(1), neg, bt); 472 register_new_node(add, add_ctrl); 473 } 474 if (add->Opcode() != Op_Add(bt)) return nullptr; 475 assert(add->Opcode() == Op_AddI || add->Opcode() == Op_AddL, ""); 476 // See if one add input is loop invariant 477 Node* add_var = add->in(1); 478 Node* add_var_ctrl = get_ctrl(add_var); 479 IdealLoopTree* add_var_loop = get_loop(add_var_ctrl); 480 Node* add_invar = add->in(2); 481 Node* add_invar_ctrl = get_ctrl(add_invar); 482 IdealLoopTree* add_invar_loop = get_loop(add_invar_ctrl); 483 if (add_invar_loop == n_loop) { 484 // Swap to find the invariant part 485 add_invar = add_var; 486 add_invar_ctrl = add_var_ctrl; 487 add_invar_loop = add_var_loop; 488 add_var = add->in(2); 489 } else if (add_var_loop != n_loop) { // Else neither input is loop invariant 490 return nullptr; 491 } 492 if (n_loop == add_invar_loop || !add_invar_loop->is_member(n_loop)) { 493 return nullptr; // No invariant part of the add? 494 } 495 496 // Yes! Reshape address expression! 497 Node* inv_scale = LShiftNode::make(add_invar, scale, bt); 498 Node* inv_scale_ctrl = 499 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? 500 add_invar_ctrl : scale_ctrl; 501 register_new_node(inv_scale, inv_scale_ctrl); 502 Node* var_scale = LShiftNode::make(add_var, scale, bt); 503 register_new_node(var_scale, n_ctrl); 504 Node* var_add = AddNode::make(var_scale, inv_scale, bt); 505 register_new_node(var_add, n_ctrl); 506 _igvn.replace_node(n, var_add); 507 return var_add; 508 } 509 return nullptr; 510 } 511 512 //------------------------------remix_address_expressions---------------------- 513 // Rework addressing expressions to get the most loop-invariant stuff 514 // moved out. We'd like to do all associative operators, but it's especially 515 // important (common) to do address expressions. 516 Node* PhaseIdealLoop::remix_address_expressions(Node* n) { 517 if (!has_ctrl(n)) return nullptr; 518 Node* n_ctrl = get_ctrl(n); 519 IdealLoopTree* n_loop = get_loop(n_ctrl); 520 521 // See if 'n' mixes loop-varying and loop-invariant inputs and 522 // itself is loop-varying. 523 524 // Only interested in binary ops (and AddP) 525 if (n->req() < 3 || n->req() > 4) return nullptr; 526 527 Node* n1_ctrl = get_ctrl(n->in( 1)); 528 Node* n2_ctrl = get_ctrl(n->in( 2)); 529 Node* n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); 530 IdealLoopTree* n1_loop = get_loop(n1_ctrl); 531 IdealLoopTree* n2_loop = get_loop(n2_ctrl); 532 IdealLoopTree* n3_loop = get_loop(n3_ctrl); 533 534 // Does one of my inputs spin in a tighter loop than self? 535 if ((n_loop->is_member(n1_loop) && n_loop != n1_loop) || 536 (n_loop->is_member(n2_loop) && n_loop != n2_loop) || 537 (n_loop->is_member(n3_loop) && n_loop != n3_loop)) { 538 return nullptr; // Leave well enough alone 539 } 540 541 // Is at least one of my inputs loop-invariant? 542 if (n1_loop == n_loop && 543 n2_loop == n_loop && 544 n3_loop == n_loop) { 545 return nullptr; // No loop-invariant inputs 546 } 547 548 Node* res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_INT); 549 if (res != nullptr) { 550 return res; 551 } 552 res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_LONG); 553 if (res != nullptr) { 554 return res; 555 } 556 557 int n_op = n->Opcode(); 558 // Replace (I+V) with (V+I) 559 if (n_op == Op_AddI || 560 n_op == Op_AddL || 561 n_op == Op_AddF || 562 n_op == Op_AddD || 563 n_op == Op_MulI || 564 n_op == Op_MulL || 565 n_op == Op_MulF || 566 n_op == Op_MulD) { 567 if (n2_loop == n_loop) { 568 assert(n1_loop != n_loop, ""); 569 n->swap_edges(1, 2); 570 } 571 } 572 573 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), 574 // but not if I2 is a constant. 575 if (n_op == Op_AddP) { 576 if (n2_loop == n_loop && n3_loop != n_loop) { 577 if (n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con()) { 578 Node* n22_ctrl = get_ctrl(n->in(2)->in(2)); 579 Node* n23_ctrl = get_ctrl(n->in(2)->in(3)); 580 IdealLoopTree* n22loop = get_loop(n22_ctrl); 581 IdealLoopTree* n23_loop = get_loop(n23_ctrl); 582 if (n22loop != n_loop && n22loop->is_member(n_loop) && 583 n23_loop == n_loop) { 584 Node* add1 = new AddPNode(n->in(1), n->in(2)->in(2), n->in(3)); 585 // Stuff new AddP in the loop preheader 586 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl)); 587 Node* add2 = new AddPNode(n->in(1), add1, n->in(2)->in(3)); 588 register_new_node(add2, n_ctrl); 589 _igvn.replace_node(n, add2); 590 return add2; 591 } 592 } 593 } 594 595 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) 596 if (n2_loop != n_loop && n3_loop == n_loop) { 597 if (n->in(3)->Opcode() == Op_AddX) { 598 Node* V = n->in(3)->in(1); 599 Node* I = n->in(3)->in(2); 600 if (is_member(n_loop,get_ctrl(V))) { 601 } else { 602 Node *tmp = V; V = I; I = tmp; 603 } 604 if (!is_member(n_loop,get_ctrl(I))) { 605 Node* add1 = new AddPNode(n->in(1), n->in(2), I); 606 // Stuff new AddP in the loop preheader 607 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl)); 608 Node* add2 = new AddPNode(n->in(1), add1, V); 609 register_new_node(add2, n_ctrl); 610 _igvn.replace_node(n, add2); 611 return add2; 612 } 613 } 614 } 615 } 616 617 return nullptr; 618 } 619 620 // Optimize ((in1[2*i] * in2[2*i]) + (in1[2*i+1] * in2[2*i+1])) 621 Node *PhaseIdealLoop::convert_add_to_muladd(Node* n) { 622 assert(n->Opcode() == Op_AddI, "sanity"); 623 Node * nn = nullptr; 624 Node * in1 = n->in(1); 625 Node * in2 = n->in(2); 626 if (in1->Opcode() == Op_MulI && in2->Opcode() == Op_MulI) { 627 IdealLoopTree* loop_n = get_loop(get_ctrl(n)); 628 if (loop_n->is_counted() && 629 loop_n->_head->as_Loop()->is_valid_counted_loop(T_INT) && 630 Matcher::match_rule_supported(Op_MulAddVS2VI) && 631 Matcher::match_rule_supported(Op_MulAddS2I)) { 632 Node* mul_in1 = in1->in(1); 633 Node* mul_in2 = in1->in(2); 634 Node* mul_in3 = in2->in(1); 635 Node* mul_in4 = in2->in(2); 636 if (mul_in1->Opcode() == Op_LoadS && 637 mul_in2->Opcode() == Op_LoadS && 638 mul_in3->Opcode() == Op_LoadS && 639 mul_in4->Opcode() == Op_LoadS) { 640 IdealLoopTree* loop1 = get_loop(get_ctrl(mul_in1)); 641 IdealLoopTree* loop2 = get_loop(get_ctrl(mul_in2)); 642 IdealLoopTree* loop3 = get_loop(get_ctrl(mul_in3)); 643 IdealLoopTree* loop4 = get_loop(get_ctrl(mul_in4)); 644 IdealLoopTree* loop5 = get_loop(get_ctrl(in1)); 645 IdealLoopTree* loop6 = get_loop(get_ctrl(in2)); 646 // All nodes should be in the same counted loop. 647 if (loop_n == loop1 && loop_n == loop2 && loop_n == loop3 && 648 loop_n == loop4 && loop_n == loop5 && loop_n == loop6) { 649 Node* adr1 = mul_in1->in(MemNode::Address); 650 Node* adr2 = mul_in2->in(MemNode::Address); 651 Node* adr3 = mul_in3->in(MemNode::Address); 652 Node* adr4 = mul_in4->in(MemNode::Address); 653 if (adr1->is_AddP() && adr2->is_AddP() && adr3->is_AddP() && adr4->is_AddP()) { 654 if ((adr1->in(AddPNode::Base) == adr3->in(AddPNode::Base)) && 655 (adr2->in(AddPNode::Base) == adr4->in(AddPNode::Base))) { 656 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in3, mul_in4); 657 register_new_node(nn, get_ctrl(n)); 658 _igvn.replace_node(n, nn); 659 return nn; 660 } else if ((adr1->in(AddPNode::Base) == adr4->in(AddPNode::Base)) && 661 (adr2->in(AddPNode::Base) == adr3->in(AddPNode::Base))) { 662 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in4, mul_in3); 663 register_new_node(nn, get_ctrl(n)); 664 _igvn.replace_node(n, nn); 665 return nn; 666 } 667 } 668 } 669 } 670 } 671 } 672 return nn; 673 } 674 675 //------------------------------conditional_move------------------------------- 676 // Attempt to replace a Phi with a conditional move. We have some pretty 677 // strict profitability requirements. All Phis at the merge point must 678 // be converted, so we can remove the control flow. We need to limit the 679 // number of c-moves to a small handful. All code that was in the side-arms 680 // of the CFG diamond is now speculatively executed. This code has to be 681 // "cheap enough". We are pretty much limited to CFG diamonds that merge 682 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. 683 Node *PhaseIdealLoop::conditional_move( Node *region ) { 684 685 assert(region->is_Region(), "sanity check"); 686 if (region->req() != 3) return nullptr; 687 688 // Check for CFG diamond 689 Node *lp = region->in(1); 690 Node *rp = region->in(2); 691 if (!lp || !rp) return nullptr; 692 Node *lp_c = lp->in(0); 693 if (lp_c == nullptr || lp_c != rp->in(0) || !lp_c->is_If()) return nullptr; 694 IfNode *iff = lp_c->as_If(); 695 696 // Check for ops pinned in an arm of the diamond. 697 // Can't remove the control flow in this case 698 if (lp->outcnt() > 1) return nullptr; 699 if (rp->outcnt() > 1) return nullptr; 700 701 IdealLoopTree* r_loop = get_loop(region); 702 assert(r_loop == get_loop(iff), "sanity"); 703 // Always convert to CMOVE if all results are used only outside this loop. 704 bool used_inside_loop = (r_loop == _ltree_root); 705 706 // Check profitability 707 int cost = 0; 708 int phis = 0; 709 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 710 Node *out = region->fast_out(i); 711 if (!out->is_Phi()) continue; // Ignore other control edges, etc 712 phis++; 713 PhiNode* phi = out->as_Phi(); 714 BasicType bt = phi->type()->basic_type(); 715 switch (bt) { 716 case T_DOUBLE: 717 case T_FLOAT: 718 if (C->use_cmove()) { 719 continue; //TODO: maybe we want to add some cost 720 } 721 cost += Matcher::float_cmove_cost(); // Could be very expensive 722 break; 723 case T_LONG: { 724 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's 725 } 726 case T_INT: // These all CMOV fine 727 case T_ADDRESS: { // (RawPtr) 728 cost++; 729 break; 730 } 731 case T_NARROWOOP: // Fall through 732 case T_OBJECT: { // Base oops are OK, but not derived oops 733 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); 734 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a 735 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus 736 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we 737 // have a Phi for the base here that we convert to a CMOVE all is well 738 // and good. But if the base is dead, we'll not make a CMOVE. Later 739 // the allocator will have to produce a base by creating a CMOVE of the 740 // relevant bases. This puts the allocator in the business of 741 // manufacturing expensive instructions, generally a bad plan. 742 // Just Say No to Conditionally-Moved Derived Pointers. 743 if (tp && tp->offset() != 0) 744 return nullptr; 745 cost++; 746 break; 747 } 748 default: 749 return nullptr; // In particular, can't do memory or I/O 750 } 751 // Add in cost any speculative ops 752 for (uint j = 1; j < region->req(); j++) { 753 Node *proj = region->in(j); 754 Node *inp = phi->in(j); 755 if (get_ctrl(inp) == proj) { // Found local op 756 cost++; 757 // Check for a chain of dependent ops; these will all become 758 // speculative in a CMOV. 759 for (uint k = 1; k < inp->req(); k++) 760 if (get_ctrl(inp->in(k)) == proj) 761 cost += ConditionalMoveLimit; // Too much speculative goo 762 } 763 } 764 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. 765 // This will likely Split-If, a higher-payoff operation. 766 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { 767 Node* use = phi->fast_out(k); 768 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr()) 769 cost += ConditionalMoveLimit; 770 // Is there a use inside the loop? 771 // Note: check only basic types since CMoveP is pinned. 772 if (!used_inside_loop && is_java_primitive(bt)) { 773 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use); 774 if (r_loop == u_loop || r_loop->is_member(u_loop)) { 775 used_inside_loop = true; 776 } 777 } 778 } 779 }//for 780 Node* bol = iff->in(1); 781 if (bol->Opcode() == Op_Opaque4) { 782 return nullptr; // Ignore loop predicate checks (the Opaque4 ensures they will go away) 783 } 784 assert(bol->Opcode() == Op_Bool, "Unexpected node"); 785 int cmp_op = bol->in(1)->Opcode(); 786 if (cmp_op == Op_SubTypeCheck) { // SubTypeCheck expansion expects an IfNode 787 return nullptr; 788 } 789 // It is expensive to generate flags from a float compare. 790 // Avoid duplicated float compare. 791 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return nullptr; 792 793 // Ignore cost if CMOVE can be moved outside the loop. 794 if (used_inside_loop && cost >= ConditionalMoveLimit) { 795 return nullptr; 796 } 797 // Check for highly predictable branch. No point in CMOV'ing if 798 // we are going to predict accurately all the time. 799 constexpr float infrequent_prob = PROB_UNLIKELY_MAG(2); 800 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) { 801 //keep going 802 } else if (iff->_prob < infrequent_prob || iff->_prob > (1.0f - infrequent_prob)) { 803 return nullptr; 804 } 805 806 // -------------- 807 // Now replace all Phis with CMOV's 808 Node *cmov_ctrl = iff->in(0); 809 uint flip = (lp->Opcode() == Op_IfTrue); 810 Node_List wq; 811 while (1) { 812 PhiNode* phi = nullptr; 813 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 814 Node *out = region->fast_out(i); 815 if (out->is_Phi()) { 816 phi = out->as_Phi(); 817 break; 818 } 819 } 820 if (phi == nullptr || _igvn.type(phi) == Type::TOP) { 821 break; 822 } 823 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); } 824 // Move speculative ops 825 wq.push(phi); 826 while (wq.size() > 0) { 827 Node *n = wq.pop(); 828 for (uint j = 1; j < n->req(); j++) { 829 Node* m = n->in(j); 830 if (m != nullptr && !is_dominator(get_ctrl(m), cmov_ctrl)) { 831 #ifndef PRODUCT 832 if (PrintOpto && VerifyLoopOptimizations) { 833 tty->print(" speculate: "); 834 m->dump(); 835 } 836 #endif 837 set_ctrl(m, cmov_ctrl); 838 wq.push(m); 839 } 840 } 841 } 842 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi)); 843 register_new_node( cmov, cmov_ctrl ); 844 _igvn.replace_node( phi, cmov ); 845 #ifndef PRODUCT 846 if (TraceLoopOpts) { 847 tty->print("CMOV "); 848 r_loop->dump_head(); 849 if (Verbose) { 850 bol->in(1)->dump(1); 851 cmov->dump(1); 852 } 853 } 854 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } ); 855 #endif 856 } 857 858 // The useless CFG diamond will fold up later; see the optimization in 859 // RegionNode::Ideal. 860 _igvn._worklist.push(region); 861 862 return iff->in(1); 863 } 864 865 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) { 866 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) { 867 Node* u = m->fast_out(i); 868 if (u->is_CFG()) { 869 if (u->is_NeverBranch()) { 870 u = u->as_NeverBranch()->proj_out(0); 871 enqueue_cfg_uses(u, wq); 872 } else { 873 wq.push(u); 874 } 875 } 876 } 877 } 878 879 // Try moving a store out of a loop, right before the loop 880 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) { 881 // Store has to be first in the loop body 882 IdealLoopTree *n_loop = get_loop(n_ctrl); 883 if (n->is_Store() && n_loop != _ltree_root && 884 n_loop->is_loop() && n_loop->_head->is_Loop() && 885 n->in(0) != nullptr) { 886 Node* address = n->in(MemNode::Address); 887 Node* value = n->in(MemNode::ValueIn); 888 Node* mem = n->in(MemNode::Memory); 889 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 890 IdealLoopTree* value_loop = get_loop(get_ctrl(value)); 891 892 // - address and value must be loop invariant 893 // - memory must be a memory Phi for the loop 894 // - Store must be the only store on this memory slice in the 895 // loop: if there's another store following this one then value 896 // written at iteration i by the second store could be overwritten 897 // at iteration i+n by the first store: it's not safe to move the 898 // first store out of the loop 899 // - nothing must observe the memory Phi: it guarantees no read 900 // before the store, we are also guaranteed the store post 901 // dominates the loop head (ignoring a possible early 902 // exit). Otherwise there would be extra Phi involved between the 903 // loop's Phi and the store. 904 // - there must be no early exit from the loop before the Store 905 // (such an exit most of the time would be an extra use of the 906 // memory Phi but sometimes is a bottom memory Phi that takes the 907 // store as input). 908 909 if (!n_loop->is_member(address_loop) && 910 !n_loop->is_member(value_loop) && 911 mem->is_Phi() && mem->in(0) == n_loop->_head && 912 mem->outcnt() == 1 && 913 mem->in(LoopNode::LoopBackControl) == n) { 914 915 assert(n_loop->_tail != nullptr, "need a tail"); 916 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop"); 917 918 // Verify that there's no early exit of the loop before the store. 919 bool ctrl_ok = false; 920 { 921 // Follow control from loop head until n, we exit the loop or 922 // we reach the tail 923 ResourceMark rm; 924 Unique_Node_List wq; 925 wq.push(n_loop->_head); 926 927 for (uint next = 0; next < wq.size(); ++next) { 928 Node *m = wq.at(next); 929 if (m == n->in(0)) { 930 ctrl_ok = true; 931 continue; 932 } 933 assert(!has_ctrl(m), "should be CFG"); 934 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) { 935 ctrl_ok = false; 936 break; 937 } 938 enqueue_cfg_uses(m, wq); 939 if (wq.size() > 10) { 940 ctrl_ok = false; 941 break; 942 } 943 } 944 } 945 if (ctrl_ok) { 946 // move the Store 947 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem); 948 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl)); 949 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl)); 950 // Disconnect the phi now. An empty phi can confuse other 951 // optimizations in this pass of loop opts. 952 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl)); 953 n_loop->_body.yank(mem); 954 955 set_ctrl_and_loop(n, n->in(0)); 956 957 return n; 958 } 959 } 960 } 961 return nullptr; 962 } 963 964 // Try moving a store out of a loop, right after the loop 965 void PhaseIdealLoop::try_move_store_after_loop(Node* n) { 966 if (n->is_Store() && n->in(0) != nullptr) { 967 Node *n_ctrl = get_ctrl(n); 968 IdealLoopTree *n_loop = get_loop(n_ctrl); 969 // Store must be in a loop 970 if (n_loop != _ltree_root && !n_loop->_irreducible) { 971 Node* address = n->in(MemNode::Address); 972 Node* value = n->in(MemNode::ValueIn); 973 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 974 // address must be loop invariant 975 if (!n_loop->is_member(address_loop)) { 976 // Store must be last on this memory slice in the loop and 977 // nothing in the loop must observe it 978 Node* phi = nullptr; 979 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 980 Node* u = n->fast_out(i); 981 if (has_ctrl(u)) { // control use? 982 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); 983 if (!n_loop->is_member(u_loop)) { 984 continue; 985 } 986 if (u->is_Phi() && u->in(0) == n_loop->_head) { 987 assert(_igvn.type(u) == Type::MEMORY, "bad phi"); 988 // multiple phis on the same slice are possible 989 if (phi != nullptr) { 990 return; 991 } 992 phi = u; 993 continue; 994 } 995 } 996 return; 997 } 998 if (phi != nullptr) { 999 // Nothing in the loop before the store (next iteration) 1000 // must observe the stored value 1001 bool mem_ok = true; 1002 { 1003 ResourceMark rm; 1004 Unique_Node_List wq; 1005 wq.push(phi); 1006 for (uint next = 0; next < wq.size() && mem_ok; ++next) { 1007 Node *m = wq.at(next); 1008 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) { 1009 Node* u = m->fast_out(i); 1010 if (u->is_Store() || u->is_Phi()) { 1011 if (u != n) { 1012 wq.push(u); 1013 mem_ok = (wq.size() <= 10); 1014 } 1015 } else { 1016 mem_ok = false; 1017 break; 1018 } 1019 } 1020 } 1021 } 1022 if (mem_ok) { 1023 // Move the store out of the loop if the LCA of all 1024 // users (except for the phi) is outside the loop. 1025 Node* hook = new Node(1); 1026 hook->init_req(0, n_ctrl); // Add an input to prevent hook from being dead 1027 _igvn.rehash_node_delayed(phi); 1028 int count = phi->replace_edge(n, hook, &_igvn); 1029 assert(count > 0, "inconsistent phi"); 1030 1031 // Compute latest point this store can go 1032 Node* lca = get_late_ctrl(n, get_ctrl(n)); 1033 if (lca->is_OuterStripMinedLoop()) { 1034 lca = lca->in(LoopNode::EntryControl); 1035 } 1036 if (n_loop->is_member(get_loop(lca))) { 1037 // LCA is in the loop - bail out 1038 _igvn.replace_node(hook, n); 1039 return; 1040 } 1041 #ifdef ASSERT 1042 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) { 1043 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined"); 1044 n_loop->_head->as_Loop()->verify_strip_mined(1); 1045 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop(); 1046 IdealLoopTree* outer_loop = get_loop(outer); 1047 assert(n_loop->_parent == outer_loop, "broken loop tree"); 1048 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state"); 1049 } 1050 #endif 1051 lca = place_outside_loop(lca, n_loop); 1052 assert(!n_loop->is_member(get_loop(lca)), "control must not be back in the loop"); 1053 assert(get_loop(lca)->_nest < n_loop->_nest || lca->in(0)->is_NeverBranch(), "must not be moved into inner loop"); 1054 1055 // Move store out of the loop 1056 _igvn.replace_node(hook, n->in(MemNode::Memory)); 1057 _igvn.replace_input_of(n, 0, lca); 1058 set_ctrl_and_loop(n, lca); 1059 1060 // Disconnect the phi now. An empty phi can confuse other 1061 // optimizations in this pass of loop opts.. 1062 if (phi->in(LoopNode::LoopBackControl) == phi) { 1063 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl)); 1064 n_loop->_body.yank(phi); 1065 } 1066 } 1067 } 1068 } 1069 } 1070 } 1071 } 1072 1073 //------------------------------split_if_with_blocks_pre----------------------- 1074 // Do the real work in a non-recursive function. Data nodes want to be 1075 // cloned in the pre-order so they can feed each other nicely. 1076 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { 1077 // Cloning these guys is unlikely to win 1078 int n_op = n->Opcode(); 1079 if (n_op == Op_MergeMem) { 1080 return n; 1081 } 1082 if (n->is_Proj()) { 1083 return n; 1084 } 1085 // Do not clone-up CmpFXXX variations, as these are always 1086 // followed by a CmpI 1087 if (n->is_Cmp()) { 1088 return n; 1089 } 1090 // Attempt to use a conditional move instead of a phi/branch 1091 if (ConditionalMoveLimit > 0 && n_op == Op_Region) { 1092 Node *cmov = conditional_move( n ); 1093 if (cmov) { 1094 return cmov; 1095 } 1096 } 1097 if (n->is_CFG() || n->is_LoadStore()) { 1098 return n; 1099 } 1100 if (n->is_Opaque1()) { // Opaque nodes cannot be mod'd 1101 if (!C->major_progress()) { // If chance of no more loop opts... 1102 _igvn._worklist.push(n); // maybe we'll remove them 1103 } 1104 return n; 1105 } 1106 1107 if (n->is_Con()) { 1108 return n; // No cloning for Con nodes 1109 } 1110 1111 Node *n_ctrl = get_ctrl(n); 1112 if (!n_ctrl) { 1113 return n; // Dead node 1114 } 1115 1116 Node* res = try_move_store_before_loop(n, n_ctrl); 1117 if (res != nullptr) { 1118 return n; 1119 } 1120 1121 // Attempt to remix address expressions for loop invariants 1122 Node *m = remix_address_expressions( n ); 1123 if( m ) return m; 1124 1125 if (n_op == Op_AddI) { 1126 Node *nn = convert_add_to_muladd( n ); 1127 if ( nn ) return nn; 1128 } 1129 1130 if (n->is_ConstraintCast()) { 1131 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this); 1132 // ConstraintCastNode::dominating_cast() uses node control input to determine domination. 1133 // Node control inputs don't necessarily agree with loop control info (due to 1134 // transformations happened in between), thus additional dominance check is needed 1135 // to keep loop info valid. 1136 if (dom_cast != nullptr && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) { 1137 _igvn.replace_node(n, dom_cast); 1138 return dom_cast; 1139 } 1140 } 1141 1142 // Determine if the Node has inputs from some local Phi. 1143 // Returns the block to clone thru. 1144 Node *n_blk = has_local_phi_input( n ); 1145 if( !n_blk ) return n; 1146 1147 // Do not clone the trip counter through on a CountedLoop 1148 // (messes up the canonical shape). 1149 if (((n_blk->is_CountedLoop() || (n_blk->is_Loop() && n_blk->as_Loop()->is_loop_nest_inner_loop())) && n->Opcode() == Op_AddI) || 1150 (n_blk->is_LongCountedLoop() && n->Opcode() == Op_AddL)) { 1151 return n; 1152 } 1153 // Pushing a shift through the iv Phi can get in the way of addressing optimizations or range check elimination 1154 if (n_blk->is_BaseCountedLoop() && n->Opcode() == Op_LShift(n_blk->as_BaseCountedLoop()->bt()) && 1155 n->in(1) == n_blk->as_BaseCountedLoop()->phi()) { 1156 return n; 1157 } 1158 1159 // Check for having no control input; not pinned. Allow 1160 // dominating control. 1161 if (n->in(0)) { 1162 Node *dom = idom(n_blk); 1163 if (dom_lca(n->in(0), dom) != n->in(0)) { 1164 return n; 1165 } 1166 } 1167 // Policy: when is it profitable. You must get more wins than 1168 // policy before it is considered profitable. Policy is usually 0, 1169 // so 1 win is considered profitable. Big merges will require big 1170 // cloning, so get a larger policy. 1171 int policy = n_blk->req() >> 2; 1172 1173 // If the loop is a candidate for range check elimination, 1174 // delay splitting through it's phi until a later loop optimization 1175 if (n_blk->is_BaseCountedLoop()) { 1176 IdealLoopTree *lp = get_loop(n_blk); 1177 if (lp && lp->_rce_candidate) { 1178 return n; 1179 } 1180 } 1181 1182 if (must_throttle_split_if()) return n; 1183 1184 // Split 'n' through the merge point if it is profitable 1185 Node *phi = split_thru_phi( n, n_blk, policy ); 1186 if (!phi) return n; 1187 1188 // Found a Phi to split thru! 1189 // Replace 'n' with the new phi 1190 _igvn.replace_node( n, phi ); 1191 // Moved a load around the loop, 'en-registering' something. 1192 if (n_blk->is_Loop() && n->is_Load() && 1193 !phi->in(LoopNode::LoopBackControl)->is_Load()) 1194 C->set_major_progress(); 1195 1196 return phi; 1197 } 1198 1199 static bool merge_point_too_heavy(Compile* C, Node* region) { 1200 // Bail out if the region and its phis have too many users. 1201 int weight = 0; 1202 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 1203 weight += region->fast_out(i)->outcnt(); 1204 } 1205 int nodes_left = C->max_node_limit() - C->live_nodes(); 1206 if (weight * 8 > nodes_left) { 1207 if (PrintOpto) { 1208 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); 1209 } 1210 return true; 1211 } else { 1212 return false; 1213 } 1214 } 1215 1216 static bool merge_point_safe(Node* region) { 1217 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode 1218 // having a PhiNode input. This sidesteps the dangerous case where the split 1219 // ConvI2LNode may become TOP if the input Value() does not 1220 // overlap the ConvI2L range, leaving a node which may not dominate its 1221 // uses. 1222 // A better fix for this problem can be found in the BugTraq entry, but 1223 // expediency for Mantis demands this hack. 1224 #ifdef _LP64 1225 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 1226 Node* n = region->fast_out(i); 1227 if (n->is_Phi()) { 1228 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 1229 Node* m = n->fast_out(j); 1230 if (m->Opcode() == Op_ConvI2L) 1231 return false; 1232 if (m->is_CastII()) { 1233 return false; 1234 } 1235 } 1236 } 1237 } 1238 #endif 1239 return true; 1240 } 1241 1242 1243 //------------------------------place_outside_loop--------------------------------- 1244 // Place some computation outside of this loop on the path to the use passed as argument 1245 Node* PhaseIdealLoop::place_outside_loop(Node* useblock, IdealLoopTree* loop) const { 1246 Node* head = loop->_head; 1247 assert(!loop->is_member(get_loop(useblock)), "must be outside loop"); 1248 if (head->is_Loop() && head->as_Loop()->is_strip_mined()) { 1249 loop = loop->_parent; 1250 assert(loop->_head->is_OuterStripMinedLoop(), "malformed strip mined loop"); 1251 } 1252 1253 // Pick control right outside the loop 1254 for (;;) { 1255 Node* dom = idom(useblock); 1256 if (loop->is_member(get_loop(dom)) || 1257 // NeverBranch nodes are not assigned to the loop when constructed 1258 (dom->is_NeverBranch() && loop->is_member(get_loop(dom->in(0))))) { 1259 break; 1260 } 1261 useblock = dom; 1262 } 1263 assert(find_non_split_ctrl(useblock) == useblock, "should be non split control"); 1264 return useblock; 1265 } 1266 1267 1268 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) { 1269 if (!n->is_If() || n->is_BaseCountedLoopEnd()) { 1270 return false; 1271 } 1272 if (!n->in(0)->is_Region()) { 1273 return false; 1274 } 1275 1276 Node* region = n->in(0); 1277 Node* dom = idom(region); 1278 if (!dom->is_If() || !n->as_If()->same_condition(dom, &_igvn)) { 1279 return false; 1280 } 1281 IfNode* dom_if = dom->as_If(); 1282 Node* proj_true = dom_if->proj_out(1); 1283 Node* proj_false = dom_if->proj_out(0); 1284 1285 for (uint i = 1; i < region->req(); i++) { 1286 if (is_dominator(proj_true, region->in(i))) { 1287 continue; 1288 } 1289 if (is_dominator(proj_false, region->in(i))) { 1290 continue; 1291 } 1292 return false; 1293 } 1294 1295 return true; 1296 } 1297 1298 1299 bool PhaseIdealLoop::can_split_if(Node* n_ctrl) { 1300 if (must_throttle_split_if()) { 1301 return false; 1302 } 1303 1304 // Do not do 'split-if' if irreducible loops are present. 1305 if (_has_irreducible_loops) { 1306 return false; 1307 } 1308 1309 if (merge_point_too_heavy(C, n_ctrl)) { 1310 return false; 1311 } 1312 1313 // Do not do 'split-if' if some paths are dead. First do dead code 1314 // elimination and then see if its still profitable. 1315 for (uint i = 1; i < n_ctrl->req(); i++) { 1316 if (n_ctrl->in(i) == C->top()) { 1317 return false; 1318 } 1319 } 1320 1321 // If trying to do a 'Split-If' at the loop head, it is only 1322 // profitable if the cmp folds up on BOTH paths. Otherwise we 1323 // risk peeling a loop forever. 1324 1325 // CNC - Disabled for now. Requires careful handling of loop 1326 // body selection for the cloned code. Also, make sure we check 1327 // for any input path not being in the same loop as n_ctrl. For 1328 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' 1329 // because the alternative loop entry points won't be converted 1330 // into LoopNodes. 1331 IdealLoopTree *n_loop = get_loop(n_ctrl); 1332 for (uint j = 1; j < n_ctrl->req(); j++) { 1333 if (get_loop(n_ctrl->in(j)) != n_loop) { 1334 return false; 1335 } 1336 } 1337 1338 // Check for safety of the merge point. 1339 if (!merge_point_safe(n_ctrl)) { 1340 return false; 1341 } 1342 1343 return true; 1344 } 1345 1346 // Detect if the node is the inner strip-mined loop 1347 // Return: null if it's not the case, or the exit of outer strip-mined loop 1348 static Node* is_inner_of_stripmined_loop(const Node* out) { 1349 Node* out_le = nullptr; 1350 1351 if (out->is_CountedLoopEnd()) { 1352 const CountedLoopNode* loop = out->as_CountedLoopEnd()->loopnode(); 1353 1354 if (loop != nullptr && loop->is_strip_mined()) { 1355 out_le = loop->in(LoopNode::EntryControl)->as_OuterStripMinedLoop()->outer_loop_exit(); 1356 } 1357 } 1358 1359 return out_le; 1360 } 1361 1362 //------------------------------split_if_with_blocks_post---------------------- 1363 // Do the real work in a non-recursive function. CFG hackery wants to be 1364 // in the post-order, so it can dirty the I-DOM info and not use the dirtied 1365 // info. 1366 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) { 1367 1368 // Cloning Cmp through Phi's involves the split-if transform. 1369 // FastLock is not used by an If 1370 if (n->is_Cmp() && !n->is_FastLock()) { 1371 Node *n_ctrl = get_ctrl(n); 1372 // Determine if the Node has inputs from some local Phi. 1373 // Returns the block to clone thru. 1374 Node *n_blk = has_local_phi_input(n); 1375 if (n_blk != n_ctrl) { 1376 return; 1377 } 1378 1379 if (!can_split_if(n_ctrl)) { 1380 return; 1381 } 1382 1383 if (n->outcnt() != 1) { 1384 return; // Multiple bool's from 1 compare? 1385 } 1386 Node *bol = n->unique_out(); 1387 assert(bol->is_Bool(), "expect a bool here"); 1388 if (bol->outcnt() != 1) { 1389 return;// Multiple branches from 1 compare? 1390 } 1391 Node *iff = bol->unique_out(); 1392 1393 // Check some safety conditions 1394 if (iff->is_If()) { // Classic split-if? 1395 if (iff->in(0) != n_ctrl) { 1396 return; // Compare must be in same blk as if 1397 } 1398 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE 1399 // Can't split CMove with different control. 1400 if (get_ctrl(iff) != n_ctrl) { 1401 return; 1402 } 1403 if (get_ctrl(iff->in(2)) == n_ctrl || 1404 get_ctrl(iff->in(3)) == n_ctrl) { 1405 return; // Inputs not yet split-up 1406 } 1407 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) { 1408 return; // Loop-invar test gates loop-varying CMOVE 1409 } 1410 } else { 1411 return; // some other kind of node, such as an Allocate 1412 } 1413 1414 // When is split-if profitable? Every 'win' on means some control flow 1415 // goes dead, so it's almost always a win. 1416 int policy = 0; 1417 // Split compare 'n' through the merge point if it is profitable 1418 Node *phi = split_thru_phi( n, n_ctrl, policy); 1419 if (!phi) { 1420 return; 1421 } 1422 1423 // Found a Phi to split thru! 1424 // Replace 'n' with the new phi 1425 _igvn.replace_node(n, phi); 1426 1427 // Now split the bool up thru the phi 1428 Node *bolphi = split_thru_phi(bol, n_ctrl, -1); 1429 guarantee(bolphi != nullptr, "null boolean phi node"); 1430 1431 _igvn.replace_node(bol, bolphi); 1432 assert(iff->in(1) == bolphi, ""); 1433 1434 if (bolphi->Value(&_igvn)->singleton()) { 1435 return; 1436 } 1437 1438 // Conditional-move? Must split up now 1439 if (!iff->is_If()) { 1440 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1); 1441 _igvn.replace_node(iff, cmovphi); 1442 return; 1443 } 1444 1445 // Now split the IF 1446 C->print_method(PHASE_BEFORE_SPLIT_IF, 4, iff); 1447 if ((PrintOpto && VerifyLoopOptimizations) || TraceLoopOpts) { 1448 tty->print_cr("Split-If"); 1449 } 1450 do_split_if(iff); 1451 C->print_method(PHASE_AFTER_SPLIT_IF, 4, iff); 1452 return; 1453 } 1454 1455 // Two identical ifs back to back can be merged 1456 if (try_merge_identical_ifs(n)) { 1457 return; 1458 } 1459 1460 // Check for an IF ready to split; one that has its 1461 // condition codes input coming from a Phi at the block start. 1462 int n_op = n->Opcode(); 1463 1464 // Check for an IF being dominated by another IF same test 1465 if (n_op == Op_If || 1466 n_op == Op_RangeCheck) { 1467 Node *bol = n->in(1); 1468 uint max = bol->outcnt(); 1469 // Check for same test used more than once? 1470 if (bol->is_Bool() && (max > 1 || bol->in(1)->is_SubTypeCheck())) { 1471 // Search up IDOMs to see if this IF is dominated. 1472 Node* cmp = bol->in(1); 1473 Node *cutoff = cmp->is_SubTypeCheck() ? dom_lca(get_ctrl(cmp->in(1)), get_ctrl(cmp->in(2))) : get_ctrl(bol); 1474 1475 // Now search up IDOMs till cutoff, looking for a dominating test 1476 Node *prevdom = n; 1477 Node *dom = idom(prevdom); 1478 while (dom != cutoff) { 1479 if (dom->req() > 1 && n->as_If()->same_condition(dom, &_igvn) && prevdom->in(0) == dom && 1480 safe_for_if_replacement(dom)) { 1481 // It's invalid to move control dependent data nodes in the inner 1482 // strip-mined loop, because: 1483 // 1) break validation of LoopNode::verify_strip_mined() 1484 // 2) move code with side-effect in strip-mined loop 1485 // Move to the exit of outer strip-mined loop in that case. 1486 Node* out_le = is_inner_of_stripmined_loop(dom); 1487 if (out_le != nullptr) { 1488 prevdom = out_le; 1489 } 1490 // Replace the dominated test with an obvious true or false. 1491 // Place it on the IGVN worklist for later cleanup. 1492 C->set_major_progress(); 1493 dominated_by(prevdom->as_IfProj(), n->as_If()); 1494 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } ); 1495 return; 1496 } 1497 prevdom = dom; 1498 dom = idom(prevdom); 1499 } 1500 } 1501 } 1502 1503 try_sink_out_of_loop(n); 1504 1505 try_move_store_after_loop(n); 1506 } 1507 1508 // Transform: 1509 // 1510 // if (some_condition) { 1511 // // body 1 1512 // } else { 1513 // // body 2 1514 // } 1515 // if (some_condition) { 1516 // // body 3 1517 // } else { 1518 // // body 4 1519 // } 1520 // 1521 // into: 1522 // 1523 // 1524 // if (some_condition) { 1525 // // body 1 1526 // // body 3 1527 // } else { 1528 // // body 2 1529 // // body 4 1530 // } 1531 bool PhaseIdealLoop::try_merge_identical_ifs(Node* n) { 1532 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) { 1533 Node *n_ctrl = n->in(0); 1534 IfNode* dom_if = idom(n_ctrl)->as_If(); 1535 if (n->in(1) != dom_if->in(1)) { 1536 assert(n->in(1)->in(1)->is_SubTypeCheck() && 1537 (n->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr || 1538 dom_if->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr), "only for subtype checks with profile data attached"); 1539 _igvn.replace_input_of(n, 1, dom_if->in(1)); 1540 } 1541 ProjNode* dom_proj_true = dom_if->proj_out(1); 1542 ProjNode* dom_proj_false = dom_if->proj_out(0); 1543 1544 // Now split the IF 1545 RegionNode* new_false_region; 1546 RegionNode* new_true_region; 1547 do_split_if(n, &new_false_region, &new_true_region); 1548 assert(new_false_region->req() == new_true_region->req(), ""); 1549 #ifdef ASSERT 1550 for (uint i = 1; i < new_false_region->req(); ++i) { 1551 assert(new_false_region->in(i)->in(0) == new_true_region->in(i)->in(0), "unexpected shape following split if"); 1552 assert(i == new_false_region->req() - 1 || new_false_region->in(i)->in(0)->in(1) == new_false_region->in(i + 1)->in(0)->in(1), "unexpected shape following split if"); 1553 } 1554 #endif 1555 assert(new_false_region->in(1)->in(0)->in(1) == dom_if->in(1), "dominating if and dominated if after split must share test"); 1556 1557 // We now have: 1558 // if (some_condition) { 1559 // // body 1 1560 // if (some_condition) { 1561 // body3: // new_true_region 1562 // // body3 1563 // } else { 1564 // goto body4; 1565 // } 1566 // } else { 1567 // // body 2 1568 // if (some_condition) { 1569 // goto body3; 1570 // } else { 1571 // body4: // new_false_region 1572 // // body4; 1573 // } 1574 // } 1575 // 1576 1577 // clone pinned nodes thru the resulting regions 1578 push_pinned_nodes_thru_region(dom_if, new_true_region); 1579 push_pinned_nodes_thru_region(dom_if, new_false_region); 1580 1581 // Optimize out the cloned ifs. Because pinned nodes were cloned, this also allows a CastPP that would be dependent 1582 // on a projection of n to have the dom_if as a control dependency. We don't want the CastPP to end up with an 1583 // unrelated control dependency. 1584 for (uint i = 1; i < new_false_region->req(); i++) { 1585 if (is_dominator(dom_proj_true, new_false_region->in(i))) { 1586 dominated_by(dom_proj_true->as_IfProj(), new_false_region->in(i)->in(0)->as_If()); 1587 } else { 1588 assert(is_dominator(dom_proj_false, new_false_region->in(i)), "bad if"); 1589 dominated_by(dom_proj_false->as_IfProj(), new_false_region->in(i)->in(0)->as_If()); 1590 } 1591 } 1592 return true; 1593 } 1594 return false; 1595 } 1596 1597 void PhaseIdealLoop::push_pinned_nodes_thru_region(IfNode* dom_if, Node* region) { 1598 for (DUIterator i = region->outs(); region->has_out(i); i++) { 1599 Node* u = region->out(i); 1600 if (!has_ctrl(u) || u->is_Phi() || !u->depends_only_on_test() || !_igvn.no_dependent_zero_check(u)) { 1601 continue; 1602 } 1603 assert(u->in(0) == region, "not a control dependent node?"); 1604 uint j = 1; 1605 for (; j < u->req(); ++j) { 1606 Node* in = u->in(j); 1607 if (!is_dominator(ctrl_or_self(in), dom_if)) { 1608 break; 1609 } 1610 } 1611 if (j == u->req()) { 1612 Node *phi = PhiNode::make_blank(region, u); 1613 for (uint k = 1; k < region->req(); ++k) { 1614 Node* clone = u->clone(); 1615 clone->set_req(0, region->in(k)); 1616 register_new_node(clone, region->in(k)); 1617 phi->init_req(k, clone); 1618 } 1619 register_new_node(phi, region); 1620 _igvn.replace_node(u, phi); 1621 --i; 1622 } 1623 } 1624 } 1625 1626 bool PhaseIdealLoop::safe_for_if_replacement(const Node* dom) const { 1627 if (!dom->is_CountedLoopEnd()) { 1628 return true; 1629 } 1630 CountedLoopEndNode* le = dom->as_CountedLoopEnd(); 1631 CountedLoopNode* cl = le->loopnode(); 1632 if (cl == nullptr) { 1633 return true; 1634 } 1635 if (!cl->is_main_loop()) { 1636 return true; 1637 } 1638 if (cl->is_canonical_loop_entry() == nullptr) { 1639 return true; 1640 } 1641 // Further unrolling is possible so loop exit condition might change 1642 return false; 1643 } 1644 1645 // See if a shared loop-varying computation has no loop-varying uses. 1646 // Happens if something is only used for JVM state in uncommon trap exits, 1647 // like various versions of induction variable+offset. Clone the 1648 // computation per usage to allow it to sink out of the loop. 1649 void PhaseIdealLoop::try_sink_out_of_loop(Node* n) { 1650 if (has_ctrl(n) && 1651 !n->is_Phi() && 1652 !n->is_Bool() && 1653 !n->is_Proj() && 1654 !n->is_MergeMem() && 1655 !n->is_CMove() && 1656 n->Opcode() != Op_Opaque4 && 1657 !n->is_Type()) { 1658 Node *n_ctrl = get_ctrl(n); 1659 IdealLoopTree *n_loop = get_loop(n_ctrl); 1660 1661 if (n->in(0) != nullptr) { 1662 IdealLoopTree* loop_ctrl = get_loop(n->in(0)); 1663 if (n_loop != loop_ctrl && n_loop->is_member(loop_ctrl)) { 1664 // n has a control input inside a loop but get_ctrl() is member of an outer loop. This could happen, for example, 1665 // for Div nodes inside a loop (control input inside loop) without a use except for an UCT (outside the loop). 1666 // Rewire control of n to right outside of the loop, regardless if its input(s) are later sunk or not. 1667 _igvn.replace_input_of(n, 0, place_outside_loop(n_ctrl, loop_ctrl)); 1668 } 1669 } 1670 if (n_loop != _ltree_root && n->outcnt() > 1) { 1671 // Compute early control: needed for anti-dependence analysis. It's also possible that as a result of 1672 // previous transformations in this loop opts round, the node can be hoisted now: early control will tell us. 1673 Node* early_ctrl = compute_early_ctrl(n, n_ctrl); 1674 if (n_loop->is_member(get_loop(early_ctrl)) && // check that this one can't be hoisted now 1675 ctrl_of_all_uses_out_of_loop(n, early_ctrl, n_loop)) { // All uses in outer loops! 1676 assert(!n->is_Store() && !n->is_LoadStore(), "no node with a side effect"); 1677 Node* outer_loop_clone = nullptr; 1678 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin;) { 1679 Node* u = n->last_out(j); // Clone private computation per use 1680 _igvn.rehash_node_delayed(u); 1681 Node* x = n->clone(); // Clone computation 1682 Node* x_ctrl = nullptr; 1683 if (u->is_Phi()) { 1684 // Replace all uses of normal nodes. Replace Phi uses 1685 // individually, so the separate Nodes can sink down 1686 // different paths. 1687 uint k = 1; 1688 while (u->in(k) != n) k++; 1689 u->set_req(k, x); 1690 // x goes next to Phi input path 1691 x_ctrl = u->in(0)->in(k); 1692 // Find control for 'x' next to use but not inside inner loops. 1693 x_ctrl = place_outside_loop(x_ctrl, n_loop); 1694 --j; 1695 } else { // Normal use 1696 if (has_ctrl(u)) { 1697 x_ctrl = get_ctrl(u); 1698 } else { 1699 x_ctrl = u->in(0); 1700 } 1701 // Find control for 'x' next to use but not inside inner loops. 1702 x_ctrl = place_outside_loop(x_ctrl, n_loop); 1703 // Replace all uses 1704 if (u->is_ConstraintCast() && _igvn.type(n)->higher_equal(u->bottom_type()) && u->in(0) == x_ctrl) { 1705 // If we're sinking a chain of data nodes, we might have inserted a cast to pin the use which is not necessary 1706 // anymore now that we're going to pin n as well 1707 _igvn.replace_node(u, x); 1708 --j; 1709 } else { 1710 int nb = u->replace_edge(n, x, &_igvn); 1711 j -= nb; 1712 } 1713 } 1714 1715 if (n->is_Load()) { 1716 // For loads, add a control edge to a CFG node outside of the loop 1717 // to force them to not combine and return back inside the loop 1718 // during GVN optimization (4641526). 1719 assert(x_ctrl == get_late_ctrl_with_anti_dep(x->as_Load(), early_ctrl, x_ctrl), "anti-dependences were already checked"); 1720 1721 IdealLoopTree* x_loop = get_loop(x_ctrl); 1722 Node* x_head = x_loop->_head; 1723 if (x_head->is_Loop() && x_head->is_OuterStripMinedLoop()) { 1724 // Do not add duplicate LoadNodes to the outer strip mined loop 1725 if (outer_loop_clone != nullptr) { 1726 _igvn.replace_node(x, outer_loop_clone); 1727 continue; 1728 } 1729 outer_loop_clone = x; 1730 } 1731 x->set_req(0, x_ctrl); 1732 } else if (n->in(0) != nullptr){ 1733 x->set_req(0, x_ctrl); 1734 } 1735 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); 1736 assert(!n_loop->is_member(get_loop(x_ctrl)), "should have moved out of loop"); 1737 register_new_node(x, x_ctrl); 1738 1739 // Chain of AddP nodes: (AddP base (AddP base (AddP base ))) 1740 // All AddP nodes must keep the same base after sinking so: 1741 // 1- We don't add a CastPP here until the last one of the chain is sunk: if part of the chain is not sunk, 1742 // their bases remain the same. 1743 // (see 2- below) 1744 assert(!x->is_AddP() || !x->in(AddPNode::Address)->is_AddP() || 1745 x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base) || 1746 !x->in(AddPNode::Address)->in(AddPNode::Base)->eqv_uncast(x->in(AddPNode::Base)), "unexpected AddP shape"); 1747 if (x->in(0) == nullptr && !x->is_DecodeNarrowPtr() && 1748 !(x->is_AddP() && x->in(AddPNode::Address)->is_AddP() && x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base))) { 1749 assert(!x->is_Load(), "load should be pinned"); 1750 // Use a cast node to pin clone out of loop 1751 Node* cast = nullptr; 1752 for (uint k = 0; k < x->req(); k++) { 1753 Node* in = x->in(k); 1754 if (in != nullptr && n_loop->is_member(get_loop(get_ctrl(in)))) { 1755 const Type* in_t = _igvn.type(in); 1756 cast = ConstraintCastNode::make_cast_for_type(x_ctrl, in, in_t, 1757 ConstraintCastNode::UnconditionalDependency, nullptr); 1758 } 1759 if (cast != nullptr) { 1760 Node* prev = _igvn.hash_find_insert(cast); 1761 if (prev != nullptr && get_ctrl(prev) == x_ctrl) { 1762 cast->destruct(&_igvn); 1763 cast = prev; 1764 } else { 1765 register_new_node(cast, x_ctrl); 1766 } 1767 x->replace_edge(in, cast); 1768 // Chain of AddP nodes: 1769 // 2- A CastPP of the base is only added now that all AddP nodes are sunk 1770 if (x->is_AddP() && k == AddPNode::Base) { 1771 update_addp_chain_base(x, n->in(AddPNode::Base), cast); 1772 } 1773 break; 1774 } 1775 } 1776 assert(cast != nullptr, "must have added a cast to pin the node"); 1777 } 1778 } 1779 _igvn.remove_dead_node(n); 1780 } 1781 _dom_lca_tags_round = 0; 1782 } 1783 } 1784 } 1785 1786 void PhaseIdealLoop::update_addp_chain_base(Node* x, Node* old_base, Node* new_base) { 1787 ResourceMark rm; 1788 Node_List wq; 1789 wq.push(x); 1790 while (wq.size() != 0) { 1791 Node* n = wq.pop(); 1792 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1793 Node* u = n->fast_out(i); 1794 if (u->is_AddP() && u->in(AddPNode::Base) == old_base) { 1795 _igvn.replace_input_of(u, AddPNode::Base, new_base); 1796 wq.push(u); 1797 } 1798 } 1799 } 1800 } 1801 1802 // Compute the early control of a node by following its inputs until we reach 1803 // nodes that are pinned. Then compute the LCA of the control of all pinned nodes. 1804 Node* PhaseIdealLoop::compute_early_ctrl(Node* n, Node* n_ctrl) { 1805 Node* early_ctrl = nullptr; 1806 ResourceMark rm; 1807 Unique_Node_List wq; 1808 wq.push(n); 1809 for (uint i = 0; i < wq.size(); i++) { 1810 Node* m = wq.at(i); 1811 Node* c = nullptr; 1812 if (m->is_CFG()) { 1813 c = m; 1814 } else if (m->pinned()) { 1815 c = m->in(0); 1816 } else { 1817 for (uint j = 0; j < m->req(); j++) { 1818 Node* in = m->in(j); 1819 if (in != nullptr) { 1820 wq.push(in); 1821 } 1822 } 1823 } 1824 if (c != nullptr) { 1825 assert(is_dominator(c, n_ctrl), "control input must dominate current control"); 1826 if (early_ctrl == nullptr || is_dominator(early_ctrl, c)) { 1827 early_ctrl = c; 1828 } 1829 } 1830 } 1831 assert(is_dominator(early_ctrl, n_ctrl), "early control must dominate current control"); 1832 return early_ctrl; 1833 } 1834 1835 bool PhaseIdealLoop::ctrl_of_all_uses_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop) { 1836 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1837 Node* u = n->fast_out(i); 1838 if (u->is_Opaque1()) { 1839 return false; // Found loop limit, bugfix for 4677003 1840 } 1841 // We can't reuse tags in PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal() so make sure calls to 1842 // get_late_ctrl_with_anti_dep() use their own tag 1843 _dom_lca_tags_round++; 1844 assert(_dom_lca_tags_round != 0, "shouldn't wrap around"); 1845 1846 if (u->is_Phi()) { 1847 for (uint j = 1; j < u->req(); ++j) { 1848 if (u->in(j) == n && !ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, u->in(0)->in(j))) { 1849 return false; 1850 } 1851 } 1852 } else { 1853 Node* ctrl = has_ctrl(u) ? get_ctrl(u) : u->in(0); 1854 if (!ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, ctrl)) { 1855 return false; 1856 } 1857 } 1858 } 1859 return true; 1860 } 1861 1862 bool PhaseIdealLoop::ctrl_of_use_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop, Node* ctrl) { 1863 if (n->is_Load()) { 1864 ctrl = get_late_ctrl_with_anti_dep(n->as_Load(), n_ctrl, ctrl); 1865 } 1866 IdealLoopTree *u_loop = get_loop(ctrl); 1867 if (u_loop == n_loop) { 1868 return false; // Found loop-varying use 1869 } 1870 if (n_loop->is_member(u_loop)) { 1871 return false; // Found use in inner loop 1872 } 1873 // Sinking a node from a pre loop to its main loop pins the node between the pre and main loops. If that node is input 1874 // to a check that's eliminated by range check elimination, it becomes input to an expression that feeds into the exit 1875 // test of the pre loop above the point in the graph where it's pinned. 1876 if (n_loop->_head->is_CountedLoop() && n_loop->_head->as_CountedLoop()->is_pre_loop() && 1877 u_loop->_head->is_CountedLoop() && u_loop->_head->as_CountedLoop()->is_main_loop() && 1878 n_loop->_next == get_loop(u_loop->_head->as_CountedLoop()->skip_strip_mined())) { 1879 return false; 1880 } 1881 return true; 1882 } 1883 1884 //------------------------------split_if_with_blocks--------------------------- 1885 // Check for aggressive application of 'split-if' optimization, 1886 // using basic block level info. 1887 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack) { 1888 Node* root = C->root(); 1889 visited.set(root->_idx); // first, mark root as visited 1890 // Do pre-visit work for root 1891 Node* n = split_if_with_blocks_pre(root); 1892 uint cnt = n->outcnt(); 1893 uint i = 0; 1894 1895 while (true) { 1896 // Visit all children 1897 if (i < cnt) { 1898 Node* use = n->raw_out(i); 1899 ++i; 1900 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { 1901 // Now do pre-visit work for this use 1902 use = split_if_with_blocks_pre(use); 1903 nstack.push(n, i); // Save parent and next use's index. 1904 n = use; // Process all children of current use. 1905 cnt = use->outcnt(); 1906 i = 0; 1907 } 1908 } 1909 else { 1910 // All of n's children have been processed, complete post-processing. 1911 if (cnt != 0 && !n->is_Con()) { 1912 assert(has_node(n), "no dead nodes"); 1913 split_if_with_blocks_post(n); 1914 } 1915 if (must_throttle_split_if()) { 1916 nstack.clear(); 1917 } 1918 if (nstack.is_empty()) { 1919 // Finished all nodes on stack. 1920 break; 1921 } 1922 // Get saved parent node and next use's index. Visit the rest of uses. 1923 n = nstack.node(); 1924 cnt = n->outcnt(); 1925 i = nstack.index(); 1926 nstack.pop(); 1927 } 1928 } 1929 } 1930 1931 1932 //============================================================================= 1933 // 1934 // C L O N E A L O O P B O D Y 1935 // 1936 1937 //------------------------------clone_iff-------------------------------------- 1938 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 1939 // "Nearly" because all Nodes have been cloned from the original in the loop, 1940 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 1941 // through the Phi recursively, and return a Bool. 1942 Node* PhaseIdealLoop::clone_iff(PhiNode* phi) { 1943 1944 // Convert this Phi into a Phi merging Bools 1945 uint i; 1946 for (i = 1; i < phi->req(); i++) { 1947 Node *b = phi->in(i); 1948 if (b->is_Phi()) { 1949 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi())); 1950 } else { 1951 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, ""); 1952 } 1953 } 1954 1955 Node* n = phi->in(1); 1956 Node* sample_opaque = nullptr; 1957 Node *sample_bool = nullptr; 1958 if (n->Opcode() == Op_Opaque4) { 1959 sample_opaque = n; 1960 sample_bool = n->in(1); 1961 assert(sample_bool->is_Bool(), "wrong type"); 1962 } else { 1963 sample_bool = n; 1964 } 1965 Node *sample_cmp = sample_bool->in(1); 1966 1967 // Make Phis to merge the Cmp's inputs. 1968 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP); 1969 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP); 1970 for (i = 1; i < phi->req(); i++) { 1971 Node *n1 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1); 1972 Node *n2 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2); 1973 phi1->set_req(i, n1); 1974 phi2->set_req(i, n2); 1975 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); 1976 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); 1977 } 1978 // See if these Phis have been made before. 1979 // Register with optimizer 1980 Node *hit1 = _igvn.hash_find_insert(phi1); 1981 if (hit1) { // Hit, toss just made Phi 1982 _igvn.remove_dead_node(phi1); // Remove new phi 1983 assert(hit1->is_Phi(), "" ); 1984 phi1 = (PhiNode*)hit1; // Use existing phi 1985 } else { // Miss 1986 _igvn.register_new_node_with_optimizer(phi1); 1987 } 1988 Node *hit2 = _igvn.hash_find_insert(phi2); 1989 if (hit2) { // Hit, toss just made Phi 1990 _igvn.remove_dead_node(phi2); // Remove new phi 1991 assert(hit2->is_Phi(), "" ); 1992 phi2 = (PhiNode*)hit2; // Use existing phi 1993 } else { // Miss 1994 _igvn.register_new_node_with_optimizer(phi2); 1995 } 1996 // Register Phis with loop/block info 1997 set_ctrl(phi1, phi->in(0)); 1998 set_ctrl(phi2, phi->in(0)); 1999 // Make a new Cmp 2000 Node *cmp = sample_cmp->clone(); 2001 cmp->set_req(1, phi1); 2002 cmp->set_req(2, phi2); 2003 _igvn.register_new_node_with_optimizer(cmp); 2004 set_ctrl(cmp, phi->in(0)); 2005 2006 // Make a new Bool 2007 Node *b = sample_bool->clone(); 2008 b->set_req(1,cmp); 2009 _igvn.register_new_node_with_optimizer(b); 2010 set_ctrl(b, phi->in(0)); 2011 2012 if (sample_opaque != nullptr) { 2013 Node* opaque = sample_opaque->clone(); 2014 opaque->set_req(1, b); 2015 _igvn.register_new_node_with_optimizer(opaque); 2016 set_ctrl(opaque, phi->in(0)); 2017 return opaque; 2018 } 2019 2020 assert(b->is_Bool(), ""); 2021 return b; 2022 } 2023 2024 //------------------------------clone_bool------------------------------------- 2025 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 2026 // "Nearly" because all Nodes have been cloned from the original in the loop, 2027 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 2028 // through the Phi recursively, and return a Bool. 2029 CmpNode*PhaseIdealLoop::clone_bool(PhiNode* phi) { 2030 uint i; 2031 // Convert this Phi into a Phi merging Bools 2032 for( i = 1; i < phi->req(); i++ ) { 2033 Node *b = phi->in(i); 2034 if( b->is_Phi() ) { 2035 _igvn.replace_input_of(phi, i, clone_bool(b->as_Phi())); 2036 } else { 2037 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); 2038 } 2039 } 2040 2041 Node *sample_cmp = phi->in(1); 2042 2043 // Make Phis to merge the Cmp's inputs. 2044 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP ); 2045 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP ); 2046 for( uint j = 1; j < phi->req(); j++ ) { 2047 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP 2048 Node *n1, *n2; 2049 if( cmp_top->is_Cmp() ) { 2050 n1 = cmp_top->in(1); 2051 n2 = cmp_top->in(2); 2052 } else { 2053 n1 = n2 = cmp_top; 2054 } 2055 phi1->set_req( j, n1 ); 2056 phi2->set_req( j, n2 ); 2057 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); 2058 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); 2059 } 2060 2061 // See if these Phis have been made before. 2062 // Register with optimizer 2063 Node *hit1 = _igvn.hash_find_insert(phi1); 2064 if( hit1 ) { // Hit, toss just made Phi 2065 _igvn.remove_dead_node(phi1); // Remove new phi 2066 assert( hit1->is_Phi(), "" ); 2067 phi1 = (PhiNode*)hit1; // Use existing phi 2068 } else { // Miss 2069 _igvn.register_new_node_with_optimizer(phi1); 2070 } 2071 Node *hit2 = _igvn.hash_find_insert(phi2); 2072 if( hit2 ) { // Hit, toss just made Phi 2073 _igvn.remove_dead_node(phi2); // Remove new phi 2074 assert( hit2->is_Phi(), "" ); 2075 phi2 = (PhiNode*)hit2; // Use existing phi 2076 } else { // Miss 2077 _igvn.register_new_node_with_optimizer(phi2); 2078 } 2079 // Register Phis with loop/block info 2080 set_ctrl(phi1, phi->in(0)); 2081 set_ctrl(phi2, phi->in(0)); 2082 // Make a new Cmp 2083 Node *cmp = sample_cmp->clone(); 2084 cmp->set_req( 1, phi1 ); 2085 cmp->set_req( 2, phi2 ); 2086 _igvn.register_new_node_with_optimizer(cmp); 2087 set_ctrl(cmp, phi->in(0)); 2088 2089 assert( cmp->is_Cmp(), "" ); 2090 return (CmpNode*)cmp; 2091 } 2092 2093 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new, 2094 IdealLoopTree* loop, IdealLoopTree* outer_loop, 2095 Node_List*& split_if_set, Node_List*& split_bool_set, 2096 Node_List*& split_cex_set, Node_List& worklist, 2097 uint new_counter, CloneLoopMode mode) { 2098 Node* nnn = old_new[old->_idx]; 2099 // Copy uses to a worklist, so I can munge the def-use info 2100 // with impunity. 2101 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) 2102 worklist.push(old->fast_out(j)); 2103 2104 while( worklist.size() ) { 2105 Node *use = worklist.pop(); 2106 if (!has_node(use)) continue; // Ignore dead nodes 2107 if (use->in(0) == C->top()) continue; 2108 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); 2109 // Check for data-use outside of loop - at least one of OLD or USE 2110 // must not be a CFG node. 2111 #ifdef ASSERT 2112 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == nullptr) { 2113 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint(); 2114 assert(mode != IgnoreStripMined, "incorrect cloning mode"); 2115 assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root(), "missed a node"); 2116 } 2117 #endif 2118 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) { 2119 2120 // If the Data use is an IF, that means we have an IF outside of the 2121 // loop that is switching on a condition that is set inside of the 2122 // loop. Happens if people set a loop-exit flag; then test the flag 2123 // in the loop to break the loop, then test is again outside of the 2124 // loop to determine which way the loop exited. 2125 // Loop predicate If node connects to Bool node through Opaque1 node. 2126 // 2127 // If the use is an AllocateArray through its ValidLengthTest input, 2128 // make sure the Bool/Cmp input is cloned down to avoid a Phi between 2129 // the AllocateArray node and its ValidLengthTest input that could cause 2130 // split if to break. 2131 if (use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque4 || 2132 (use->Opcode() == Op_AllocateArray && use->in(AllocateNode::ValidLengthTest) == old)) { 2133 // Since this code is highly unlikely, we lazily build the worklist 2134 // of such Nodes to go split. 2135 if (!split_if_set) { 2136 split_if_set = new Node_List(); 2137 } 2138 split_if_set->push(use); 2139 } 2140 if (use->is_Bool()) { 2141 if (!split_bool_set) { 2142 split_bool_set = new Node_List(); 2143 } 2144 split_bool_set->push(use); 2145 } 2146 if (use->Opcode() == Op_CreateEx) { 2147 if (!split_cex_set) { 2148 split_cex_set = new Node_List(); 2149 } 2150 split_cex_set->push(use); 2151 } 2152 2153 2154 // Get "block" use is in 2155 uint idx = 0; 2156 while( use->in(idx) != old ) idx++; 2157 Node *prev = use->is_CFG() ? use : get_ctrl(use); 2158 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" ); 2159 Node* cfg = (prev->_idx >= new_counter && prev->is_Region()) 2160 ? prev->in(2) 2161 : idom(prev); 2162 if( use->is_Phi() ) // Phi use is in prior block 2163 cfg = prev->in(idx); // NOT in block of Phi itself 2164 if (cfg->is_top()) { // Use is dead? 2165 _igvn.replace_input_of(use, idx, C->top()); 2166 continue; 2167 } 2168 2169 // If use is referenced through control edge... (idx == 0) 2170 if (mode == IgnoreStripMined && idx == 0) { 2171 LoopNode *head = loop->_head->as_Loop(); 2172 if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) { 2173 // That node is outside the inner loop, leave it outside the 2174 // outer loop as well to not confuse verification code. 2175 assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop"); 2176 _igvn.replace_input_of(use, 0, head->outer_loop_exit()); 2177 continue; 2178 } 2179 } 2180 2181 while(!outer_loop->is_member(get_loop(cfg))) { 2182 prev = cfg; 2183 cfg = (cfg->_idx >= new_counter && cfg->is_Region()) ? cfg->in(2) : idom(cfg); 2184 } 2185 // If the use occurs after merging several exits from the loop, then 2186 // old value must have dominated all those exits. Since the same old 2187 // value was used on all those exits we did not need a Phi at this 2188 // merge point. NOW we do need a Phi here. Each loop exit value 2189 // is now merged with the peeled body exit; each exit gets its own 2190 // private Phi and those Phis need to be merged here. 2191 Node *phi; 2192 if( prev->is_Region() ) { 2193 if( idx == 0 ) { // Updating control edge? 2194 phi = prev; // Just use existing control 2195 } else { // Else need a new Phi 2196 phi = PhiNode::make( prev, old ); 2197 // Now recursively fix up the new uses of old! 2198 for( uint i = 1; i < prev->req(); i++ ) { 2199 worklist.push(phi); // Onto worklist once for each 'old' input 2200 } 2201 } 2202 } else { 2203 // Get new RegionNode merging old and new loop exits 2204 prev = old_new[prev->_idx]; 2205 assert( prev, "just made this in step 7" ); 2206 if( idx == 0) { // Updating control edge? 2207 phi = prev; // Just use existing control 2208 } else { // Else need a new Phi 2209 // Make a new Phi merging data values properly 2210 phi = PhiNode::make( prev, old ); 2211 phi->set_req( 1, nnn ); 2212 } 2213 } 2214 // If inserting a new Phi, check for prior hits 2215 if( idx != 0 ) { 2216 Node *hit = _igvn.hash_find_insert(phi); 2217 if( hit == nullptr ) { 2218 _igvn.register_new_node_with_optimizer(phi); // Register new phi 2219 } else { // or 2220 // Remove the new phi from the graph and use the hit 2221 _igvn.remove_dead_node(phi); 2222 phi = hit; // Use existing phi 2223 } 2224 set_ctrl(phi, prev); 2225 } 2226 // Make 'use' use the Phi instead of the old loop body exit value 2227 assert(use->in(idx) == old, "old is still input of use"); 2228 // We notify all uses of old, including use, and the indirect uses, 2229 // that may now be optimized because we have replaced old with phi. 2230 _igvn.add_users_to_worklist(old); 2231 _igvn.replace_input_of(use, idx, phi); 2232 if( use->_idx >= new_counter ) { // If updating new phis 2233 // Not needed for correctness, but prevents a weak assert 2234 // in AddPNode from tripping (when we end up with different 2235 // base & derived Phis that will become the same after 2236 // IGVN does CSE). 2237 Node *hit = _igvn.hash_find_insert(use); 2238 if( hit ) // Go ahead and re-hash for hits. 2239 _igvn.replace_node( use, hit ); 2240 } 2241 } 2242 } 2243 } 2244 2245 static void collect_nodes_in_outer_loop_not_reachable_from_sfpt(Node* n, const IdealLoopTree *loop, const IdealLoopTree* outer_loop, 2246 const Node_List &old_new, Unique_Node_List& wq, PhaseIdealLoop* phase, 2247 bool check_old_new) { 2248 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2249 Node* u = n->fast_out(j); 2250 assert(check_old_new || old_new[u->_idx] == nullptr, "shouldn't have been cloned"); 2251 if (!u->is_CFG() && (!check_old_new || old_new[u->_idx] == nullptr)) { 2252 Node* c = phase->get_ctrl(u); 2253 IdealLoopTree* u_loop = phase->get_loop(c); 2254 assert(!loop->is_member(u_loop) || !loop->_body.contains(u), "can be in outer loop or out of both loops only"); 2255 if (!loop->is_member(u_loop)) { 2256 if (outer_loop->is_member(u_loop)) { 2257 wq.push(u); 2258 } else { 2259 // nodes pinned with control in the outer loop but not referenced from the safepoint must be moved out of 2260 // the outer loop too 2261 Node* u_c = u->in(0); 2262 if (u_c != nullptr) { 2263 IdealLoopTree* u_c_loop = phase->get_loop(u_c); 2264 if (outer_loop->is_member(u_c_loop) && !loop->is_member(u_c_loop)) { 2265 wq.push(u); 2266 } 2267 } 2268 } 2269 } 2270 } 2271 } 2272 } 2273 2274 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop, 2275 IdealLoopTree* outer_loop, int dd, Node_List &old_new, 2276 Node_List& extra_data_nodes) { 2277 if (head->is_strip_mined() && mode != IgnoreStripMined) { 2278 CountedLoopNode* cl = head->as_CountedLoop(); 2279 Node* l = cl->outer_loop(); 2280 Node* tail = cl->outer_loop_tail(); 2281 IfNode* le = cl->outer_loop_end(); 2282 Node* sfpt = cl->outer_safepoint(); 2283 CountedLoopEndNode* cle = cl->loopexit(); 2284 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop(); 2285 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null(); 2286 Node* cle_out = cle->proj_out(false); 2287 2288 Node* new_sfpt = nullptr; 2289 Node* new_cle_out = cle_out->clone(); 2290 old_new.map(cle_out->_idx, new_cle_out); 2291 if (mode == CloneIncludesStripMined) { 2292 // clone outer loop body 2293 Node* new_l = l->clone(); 2294 Node* new_tail = tail->clone(); 2295 IfNode* new_le = le->clone()->as_If(); 2296 new_sfpt = sfpt->clone(); 2297 2298 set_loop(new_l, outer_loop->_parent); 2299 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd); 2300 set_loop(new_cle_out, outer_loop->_parent); 2301 set_idom(new_cle_out, new_cle, dd); 2302 set_loop(new_sfpt, outer_loop->_parent); 2303 set_idom(new_sfpt, new_cle_out, dd); 2304 set_loop(new_le, outer_loop->_parent); 2305 set_idom(new_le, new_sfpt, dd); 2306 set_loop(new_tail, outer_loop->_parent); 2307 set_idom(new_tail, new_le, dd); 2308 set_idom(new_cl, new_l, dd); 2309 2310 old_new.map(l->_idx, new_l); 2311 old_new.map(tail->_idx, new_tail); 2312 old_new.map(le->_idx, new_le); 2313 old_new.map(sfpt->_idx, new_sfpt); 2314 2315 new_l->set_req(LoopNode::LoopBackControl, new_tail); 2316 new_l->set_req(0, new_l); 2317 new_tail->set_req(0, new_le); 2318 new_le->set_req(0, new_sfpt); 2319 new_sfpt->set_req(0, new_cle_out); 2320 new_cle_out->set_req(0, new_cle); 2321 new_cl->set_req(LoopNode::EntryControl, new_l); 2322 2323 _igvn.register_new_node_with_optimizer(new_l); 2324 _igvn.register_new_node_with_optimizer(new_tail); 2325 _igvn.register_new_node_with_optimizer(new_le); 2326 } else { 2327 Node *newhead = old_new[loop->_head->_idx]; 2328 newhead->as_Loop()->clear_strip_mined(); 2329 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl)); 2330 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); 2331 } 2332 // Look at data node that were assigned a control in the outer 2333 // loop: they are kept in the outer loop by the safepoint so start 2334 // from the safepoint node's inputs. 2335 IdealLoopTree* outer_loop = get_loop(l); 2336 Node_Stack stack(2); 2337 stack.push(sfpt, 1); 2338 uint new_counter = C->unique(); 2339 while (stack.size() > 0) { 2340 Node* n = stack.node(); 2341 uint i = stack.index(); 2342 while (i < n->req() && 2343 (n->in(i) == nullptr || 2344 !has_ctrl(n->in(i)) || 2345 get_loop(get_ctrl(n->in(i))) != outer_loop || 2346 (old_new[n->in(i)->_idx] != nullptr && old_new[n->in(i)->_idx]->_idx >= new_counter))) { 2347 i++; 2348 } 2349 if (i < n->req()) { 2350 stack.set_index(i+1); 2351 stack.push(n->in(i), 0); 2352 } else { 2353 assert(old_new[n->_idx] == nullptr || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet"); 2354 Node* m = n == sfpt ? new_sfpt : n->clone(); 2355 if (m != nullptr) { 2356 for (uint i = 0; i < n->req(); i++) { 2357 if (m->in(i) != nullptr && old_new[m->in(i)->_idx] != nullptr) { 2358 m->set_req(i, old_new[m->in(i)->_idx]); 2359 } 2360 } 2361 } else { 2362 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?"); 2363 } 2364 if (n != sfpt) { 2365 extra_data_nodes.push(n); 2366 _igvn.register_new_node_with_optimizer(m); 2367 assert(get_ctrl(n) == cle_out, "what other control?"); 2368 set_ctrl(m, new_cle_out); 2369 old_new.map(n->_idx, m); 2370 } 2371 stack.pop(); 2372 } 2373 } 2374 if (mode == CloneIncludesStripMined) { 2375 _igvn.register_new_node_with_optimizer(new_sfpt); 2376 _igvn.register_new_node_with_optimizer(new_cle_out); 2377 } 2378 // Some other transformation may have pessimistically assigned some 2379 // data nodes to the outer loop. Set their control so they are out 2380 // of the outer loop. 2381 ResourceMark rm; 2382 Unique_Node_List wq; 2383 for (uint i = 0; i < extra_data_nodes.size(); i++) { 2384 Node* old = extra_data_nodes.at(i); 2385 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true); 2386 } 2387 2388 for (uint i = 0; i < loop->_body.size(); i++) { 2389 Node* old = loop->_body.at(i); 2390 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true); 2391 } 2392 2393 Node* inner_out = sfpt->in(0); 2394 if (inner_out->outcnt() > 1) { 2395 collect_nodes_in_outer_loop_not_reachable_from_sfpt(inner_out, loop, outer_loop, old_new, wq, this, true); 2396 } 2397 2398 Node* new_ctrl = cl->outer_loop_exit(); 2399 assert(get_loop(new_ctrl) != outer_loop, "must be out of the loop nest"); 2400 for (uint i = 0; i < wq.size(); i++) { 2401 Node* n = wq.at(i); 2402 set_ctrl(n, new_ctrl); 2403 if (n->in(0) != nullptr) { 2404 _igvn.replace_input_of(n, 0, new_ctrl); 2405 } 2406 collect_nodes_in_outer_loop_not_reachable_from_sfpt(n, loop, outer_loop, old_new, wq, this, false); 2407 } 2408 } else { 2409 Node *newhead = old_new[loop->_head->_idx]; 2410 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); 2411 } 2412 } 2413 2414 //------------------------------clone_loop------------------------------------- 2415 // 2416 // C L O N E A L O O P B O D Y 2417 // 2418 // This is the basic building block of the loop optimizations. It clones an 2419 // entire loop body. It makes an old_new loop body mapping; with this mapping 2420 // you can find the new-loop equivalent to an old-loop node. All new-loop 2421 // nodes are exactly equal to their old-loop counterparts, all edges are the 2422 // same. All exits from the old-loop now have a RegionNode that merges the 2423 // equivalent new-loop path. This is true even for the normal "loop-exit" 2424 // condition. All uses of loop-invariant old-loop values now come from (one 2425 // or more) Phis that merge their new-loop equivalents. 2426 // 2427 // This operation leaves the graph in an illegal state: there are two valid 2428 // control edges coming from the loop pre-header to both loop bodies. I'll 2429 // definitely have to hack the graph after running this transform. 2430 // 2431 // From this building block I will further edit edges to perform loop peeling 2432 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. 2433 // 2434 // Parameter side_by_size_idom: 2435 // When side_by_size_idom is null, the dominator tree is constructed for 2436 // the clone loop to dominate the original. Used in construction of 2437 // pre-main-post loop sequence. 2438 // When nonnull, the clone and original are side-by-side, both are 2439 // dominated by the side_by_side_idom node. Used in construction of 2440 // unswitched loops. 2441 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, 2442 CloneLoopMode mode, Node* side_by_side_idom) { 2443 2444 LoopNode* head = loop->_head->as_Loop(); 2445 head->verify_strip_mined(1); 2446 2447 if (C->do_vector_loop() && PrintOpto) { 2448 const char* mname = C->method()->name()->as_quoted_ascii(); 2449 if (mname != nullptr) { 2450 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname); 2451 } 2452 } 2453 2454 CloneMap& cm = C->clone_map(); 2455 if (C->do_vector_loop()) { 2456 cm.set_clone_idx(cm.max_gen()+1); 2457 #ifndef PRODUCT 2458 if (PrintOpto) { 2459 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx()); 2460 loop->dump_head(); 2461 } 2462 #endif 2463 } 2464 2465 // Step 1: Clone the loop body. Make the old->new mapping. 2466 clone_loop_body(loop->_body, old_new, &cm); 2467 2468 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop; 2469 2470 // Step 2: Fix the edges in the new body. If the old input is outside the 2471 // loop use it. If the old input is INside the loop, use the corresponding 2472 // new node instead. 2473 fix_body_edges(loop->_body, loop, old_new, dd, outer_loop->_parent, false); 2474 2475 Node_List extra_data_nodes; // data nodes in the outer strip mined loop 2476 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes); 2477 2478 // Step 3: Now fix control uses. Loop varying control uses have already 2479 // been fixed up (as part of all input edges in Step 2). Loop invariant 2480 // control uses must be either an IfFalse or an IfTrue. Make a merge 2481 // point to merge the old and new IfFalse/IfTrue nodes; make the use 2482 // refer to this. 2483 Node_List worklist; 2484 uint new_counter = C->unique(); 2485 fix_ctrl_uses(loop->_body, loop, old_new, mode, side_by_side_idom, &cm, worklist); 2486 2487 // Step 4: If loop-invariant use is not control, it must be dominated by a 2488 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region 2489 // there if needed. Make a Phi there merging old and new used values. 2490 Node_List *split_if_set = nullptr; 2491 Node_List *split_bool_set = nullptr; 2492 Node_List *split_cex_set = nullptr; 2493 fix_data_uses(loop->_body, loop, mode, outer_loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set); 2494 2495 for (uint i = 0; i < extra_data_nodes.size(); i++) { 2496 Node* old = extra_data_nodes.at(i); 2497 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set, 2498 split_bool_set, split_cex_set, worklist, new_counter, 2499 mode); 2500 } 2501 2502 // Check for IFs that need splitting/cloning. Happens if an IF outside of 2503 // the loop uses a condition set in the loop. The original IF probably 2504 // takes control from one or more OLD Regions (which in turn get from NEW 2505 // Regions). In any case, there will be a set of Phis for each merge point 2506 // from the IF up to where the original BOOL def exists the loop. 2507 finish_clone_loop(split_if_set, split_bool_set, split_cex_set); 2508 2509 } 2510 2511 void PhaseIdealLoop::finish_clone_loop(Node_List* split_if_set, Node_List* split_bool_set, Node_List* split_cex_set) { 2512 if (split_if_set) { 2513 while (split_if_set->size()) { 2514 Node *iff = split_if_set->pop(); 2515 uint input = iff->Opcode() == Op_AllocateArray ? AllocateNode::ValidLengthTest : 1; 2516 if (iff->in(input)->is_Phi()) { 2517 Node *b = clone_iff(iff->in(input)->as_Phi()); 2518 _igvn.replace_input_of(iff, input, b); 2519 } 2520 } 2521 } 2522 if (split_bool_set) { 2523 while (split_bool_set->size()) { 2524 Node *b = split_bool_set->pop(); 2525 Node *phi = b->in(1); 2526 assert(phi->is_Phi(), ""); 2527 CmpNode *cmp = clone_bool((PhiNode*) phi); 2528 _igvn.replace_input_of(b, 1, cmp); 2529 } 2530 } 2531 if (split_cex_set) { 2532 while (split_cex_set->size()) { 2533 Node *b = split_cex_set->pop(); 2534 assert(b->in(0)->is_Region(), ""); 2535 assert(b->in(1)->is_Phi(), ""); 2536 assert(b->in(0)->in(0) == b->in(1)->in(0), ""); 2537 split_up(b, b->in(0), nullptr); 2538 } 2539 } 2540 } 2541 2542 void PhaseIdealLoop::fix_data_uses(Node_List& body, IdealLoopTree* loop, CloneLoopMode mode, IdealLoopTree* outer_loop, 2543 uint new_counter, Node_List &old_new, Node_List &worklist, Node_List*& split_if_set, 2544 Node_List*& split_bool_set, Node_List*& split_cex_set) { 2545 for(uint i = 0; i < body.size(); i++ ) { 2546 Node* old = body.at(i); 2547 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set, 2548 split_bool_set, split_cex_set, worklist, new_counter, 2549 mode); 2550 } 2551 } 2552 2553 void PhaseIdealLoop::fix_ctrl_uses(const Node_List& body, const IdealLoopTree* loop, Node_List &old_new, CloneLoopMode mode, 2554 Node* side_by_side_idom, CloneMap* cm, Node_List &worklist) { 2555 LoopNode* head = loop->_head->as_Loop(); 2556 for(uint i = 0; i < body.size(); i++ ) { 2557 Node* old = body.at(i); 2558 if( !old->is_CFG() ) continue; 2559 2560 // Copy uses to a worklist, so I can munge the def-use info 2561 // with impunity. 2562 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) { 2563 worklist.push(old->fast_out(j)); 2564 } 2565 2566 while (worklist.size()) { // Visit all uses 2567 Node *use = worklist.pop(); 2568 if (!has_node(use)) continue; // Ignore dead nodes 2569 IdealLoopTree *use_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use ); 2570 if (!loop->is_member(use_loop) && use->is_CFG()) { 2571 // Both OLD and USE are CFG nodes here. 2572 assert(use->is_Proj(), "" ); 2573 Node* nnn = old_new[old->_idx]; 2574 2575 Node* newuse = nullptr; 2576 if (head->is_strip_mined() && mode != IgnoreStripMined) { 2577 CountedLoopNode* cl = head->as_CountedLoop(); 2578 CountedLoopEndNode* cle = cl->loopexit(); 2579 Node* cle_out = cle->proj_out_or_null(false); 2580 if (use == cle_out) { 2581 IfNode* le = cl->outer_loop_end(); 2582 use = le->proj_out(false); 2583 use_loop = get_loop(use); 2584 if (mode == CloneIncludesStripMined) { 2585 nnn = old_new[le->_idx]; 2586 } else { 2587 newuse = old_new[cle_out->_idx]; 2588 } 2589 } 2590 } 2591 if (newuse == nullptr) { 2592 newuse = use->clone(); 2593 } 2594 2595 // Clone the loop exit control projection 2596 if (C->do_vector_loop() && cm != nullptr) { 2597 cm->verify_insert_and_clone(use, newuse, cm->clone_idx()); 2598 } 2599 newuse->set_req(0,nnn); 2600 _igvn.register_new_node_with_optimizer(newuse); 2601 set_loop(newuse, use_loop); 2602 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); 2603 2604 // We need a Region to merge the exit from the peeled body and the 2605 // exit from the old loop body. 2606 RegionNode *r = new RegionNode(3); 2607 uint dd_r = MIN2(dom_depth(newuse), dom_depth(use)); 2608 assert(dd_r >= dom_depth(dom_lca(newuse, use)), "" ); 2609 2610 // The original user of 'use' uses 'r' instead. 2611 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { 2612 Node* useuse = use->last_out(l); 2613 _igvn.rehash_node_delayed(useuse); 2614 uint uses_found = 0; 2615 if (useuse->in(0) == use) { 2616 useuse->set_req(0, r); 2617 uses_found++; 2618 if (useuse->is_CFG()) { 2619 // This is not a dom_depth > dd_r because when new 2620 // control flow is constructed by a loop opt, a node and 2621 // its dominator can end up at the same dom_depth 2622 assert(dom_depth(useuse) >= dd_r, ""); 2623 set_idom(useuse, r, dom_depth(useuse)); 2624 } 2625 } 2626 for (uint k = 1; k < useuse->req(); k++) { 2627 if( useuse->in(k) == use ) { 2628 useuse->set_req(k, r); 2629 uses_found++; 2630 if (useuse->is_Loop() && k == LoopNode::EntryControl) { 2631 // This is not a dom_depth > dd_r because when new 2632 // control flow is constructed by a loop opt, a node 2633 // and its dominator can end up at the same dom_depth 2634 assert(dom_depth(useuse) >= dd_r , ""); 2635 set_idom(useuse, r, dom_depth(useuse)); 2636 } 2637 } 2638 } 2639 l -= uses_found; // we deleted 1 or more copies of this edge 2640 } 2641 2642 assert(use->is_Proj(), "loop exit should be projection"); 2643 // lazy_replace() below moves all nodes that are: 2644 // - control dependent on the loop exit or 2645 // - have control set to the loop exit 2646 // below the post-loop merge point. lazy_replace() takes a dead control as first input. To make it 2647 // possible to use it, the loop exit projection is cloned and becomes the new exit projection. The initial one 2648 // becomes dead and is "replaced" by the region. 2649 Node* use_clone = use->clone(); 2650 register_control(use_clone, use_loop, idom(use), dom_depth(use)); 2651 // Now finish up 'r' 2652 r->set_req(1, newuse); 2653 r->set_req(2, use_clone); 2654 _igvn.register_new_node_with_optimizer(r); 2655 set_loop(r, use_loop); 2656 set_idom(r, (side_by_side_idom == nullptr) ? newuse->in(0) : side_by_side_idom, dd_r); 2657 lazy_replace(use, r); 2658 // Map the (cloned) old use to the new merge point 2659 old_new.map(use_clone->_idx, r); 2660 } // End of if a loop-exit test 2661 } 2662 } 2663 } 2664 2665 void PhaseIdealLoop::fix_body_edges(const Node_List &body, IdealLoopTree* loop, const Node_List &old_new, int dd, 2666 IdealLoopTree* parent, bool partial) { 2667 for(uint i = 0; i < body.size(); i++ ) { 2668 Node *old = body.at(i); 2669 Node *nnn = old_new[old->_idx]; 2670 // Fix CFG/Loop controlling the new node 2671 if (has_ctrl(old)) { 2672 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); 2673 } else { 2674 set_loop(nnn, parent); 2675 if (old->outcnt() > 0) { 2676 Node* dom = idom(old); 2677 if (old_new[dom->_idx] != nullptr) { 2678 dom = old_new[dom->_idx]; 2679 set_idom(nnn, dom, dd ); 2680 } 2681 } 2682 } 2683 // Correct edges to the new node 2684 for (uint j = 0; j < nnn->req(); j++) { 2685 Node *n = nnn->in(j); 2686 if (n != nullptr) { 2687 IdealLoopTree *old_in_loop = get_loop(has_ctrl(n) ? get_ctrl(n) : n); 2688 if (loop->is_member(old_in_loop)) { 2689 if (old_new[n->_idx] != nullptr) { 2690 nnn->set_req(j, old_new[n->_idx]); 2691 } else { 2692 assert(!body.contains(n), ""); 2693 assert(partial, "node not cloned"); 2694 } 2695 } 2696 } 2697 } 2698 _igvn.hash_find_insert(nnn); 2699 } 2700 } 2701 2702 void PhaseIdealLoop::clone_loop_body(const Node_List& body, Node_List &old_new, CloneMap* cm) { 2703 for (uint i = 0; i < body.size(); i++) { 2704 Node* old = body.at(i); 2705 Node* nnn = old->clone(); 2706 old_new.map(old->_idx, nnn); 2707 if (C->do_vector_loop() && cm != nullptr) { 2708 cm->verify_insert_and_clone(old, nnn, cm->clone_idx()); 2709 } 2710 _igvn.register_new_node_with_optimizer(nnn); 2711 } 2712 } 2713 2714 2715 //---------------------- stride_of_possible_iv ------------------------------------- 2716 // Looks for an iff/bool/comp with one operand of the compare 2717 // being a cycle involving an add and a phi, 2718 // with an optional truncation (left-shift followed by a right-shift) 2719 // of the add. Returns zero if not an iv. 2720 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { 2721 Node* trunc1 = nullptr; 2722 Node* trunc2 = nullptr; 2723 const TypeInteger* ttype = nullptr; 2724 if (!iff->is_If() || iff->in(1) == nullptr || !iff->in(1)->is_Bool()) { 2725 return 0; 2726 } 2727 BoolNode* bl = iff->in(1)->as_Bool(); 2728 Node* cmp = bl->in(1); 2729 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) { 2730 return 0; 2731 } 2732 // Must have an invariant operand 2733 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { 2734 return 0; 2735 } 2736 Node* add2 = nullptr; 2737 Node* cmp1 = cmp->in(1); 2738 if (cmp1->is_Phi()) { 2739 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) 2740 Node* phi = cmp1; 2741 for (uint i = 1; i < phi->req(); i++) { 2742 Node* in = phi->in(i); 2743 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, 2744 &trunc1, &trunc2, &ttype, T_INT); 2745 if (add && add->in(1) == phi) { 2746 add2 = add->in(2); 2747 break; 2748 } 2749 } 2750 } else { 2751 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) 2752 Node* addtrunc = cmp1; 2753 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, 2754 &trunc1, &trunc2, &ttype, T_INT); 2755 if (add && add->in(1)->is_Phi()) { 2756 Node* phi = add->in(1); 2757 for (uint i = 1; i < phi->req(); i++) { 2758 if (phi->in(i) == addtrunc) { 2759 add2 = add->in(2); 2760 break; 2761 } 2762 } 2763 } 2764 } 2765 if (add2 != nullptr) { 2766 const TypeInt* add2t = _igvn.type(add2)->is_int(); 2767 if (add2t->is_con()) { 2768 return add2t->get_con(); 2769 } 2770 } 2771 return 0; 2772 } 2773 2774 2775 //---------------------- stay_in_loop ------------------------------------- 2776 // Return the (unique) control output node that's in the loop (if it exists.) 2777 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { 2778 Node* unique = nullptr; 2779 if (!n) return nullptr; 2780 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 2781 Node* use = n->fast_out(i); 2782 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { 2783 if (unique != nullptr) { 2784 return nullptr; 2785 } 2786 unique = use; 2787 } 2788 } 2789 return unique; 2790 } 2791 2792 //------------------------------ register_node ------------------------------------- 2793 // Utility to register node "n" with PhaseIdealLoop 2794 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree* loop, Node* pred, uint ddepth) { 2795 _igvn.register_new_node_with_optimizer(n); 2796 loop->_body.push(n); 2797 if (n->is_CFG()) { 2798 set_loop(n, loop); 2799 set_idom(n, pred, ddepth); 2800 } else { 2801 set_ctrl(n, pred); 2802 } 2803 } 2804 2805 //------------------------------ proj_clone ------------------------------------- 2806 // Utility to create an if-projection 2807 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { 2808 ProjNode* c = p->clone()->as_Proj(); 2809 c->set_req(0, iff); 2810 return c; 2811 } 2812 2813 //------------------------------ short_circuit_if ------------------------------------- 2814 // Force the iff control output to be the live_proj 2815 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { 2816 guarantee(live_proj != nullptr, "null projection"); 2817 int proj_con = live_proj->_con; 2818 assert(proj_con == 0 || proj_con == 1, "false or true projection"); 2819 Node *con = _igvn.intcon(proj_con); 2820 set_ctrl(con, C->root()); 2821 if (iff) { 2822 iff->set_req(1, con); 2823 } 2824 return con; 2825 } 2826 2827 //------------------------------ insert_if_before_proj ------------------------------------- 2828 // Insert a new if before an if projection (* - new node) 2829 // 2830 // before 2831 // if(test) 2832 // / \ 2833 // v v 2834 // other-proj proj (arg) 2835 // 2836 // after 2837 // if(test) 2838 // / \ 2839 // / v 2840 // | * proj-clone 2841 // v | 2842 // other-proj v 2843 // * new_if(relop(cmp[IU](left,right))) 2844 // / \ 2845 // v v 2846 // * new-proj proj 2847 // (returned) 2848 // 2849 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { 2850 IfNode* iff = proj->in(0)->as_If(); 2851 IdealLoopTree *loop = get_loop(proj); 2852 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 2853 uint ddepth = dom_depth(proj); 2854 2855 _igvn.rehash_node_delayed(iff); 2856 _igvn.rehash_node_delayed(proj); 2857 2858 proj->set_req(0, nullptr); // temporary disconnect 2859 ProjNode* proj2 = proj_clone(proj, iff); 2860 register_node(proj2, loop, iff, ddepth); 2861 2862 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right); 2863 register_node(cmp, loop, proj2, ddepth); 2864 2865 BoolNode* bol = new BoolNode(cmp, relop); 2866 register_node(bol, loop, proj2, ddepth); 2867 2868 int opcode = iff->Opcode(); 2869 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode"); 2870 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt): 2871 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt); 2872 register_node(new_if, loop, proj2, ddepth); 2873 2874 proj->set_req(0, new_if); // reattach 2875 set_idom(proj, new_if, ddepth); 2876 2877 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); 2878 guarantee(new_exit != nullptr, "null exit node"); 2879 register_node(new_exit, get_loop(other_proj), new_if, ddepth); 2880 2881 return new_exit; 2882 } 2883 2884 //------------------------------ insert_region_before_proj ------------------------------------- 2885 // Insert a region before an if projection (* - new node) 2886 // 2887 // before 2888 // if(test) 2889 // / | 2890 // v | 2891 // proj v 2892 // other-proj 2893 // 2894 // after 2895 // if(test) 2896 // / | 2897 // v | 2898 // * proj-clone v 2899 // | other-proj 2900 // v 2901 // * new-region 2902 // | 2903 // v 2904 // * dum_if 2905 // / \ 2906 // v \ 2907 // * dum-proj v 2908 // proj 2909 // 2910 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { 2911 IfNode* iff = proj->in(0)->as_If(); 2912 IdealLoopTree *loop = get_loop(proj); 2913 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 2914 uint ddepth = dom_depth(proj); 2915 2916 _igvn.rehash_node_delayed(iff); 2917 _igvn.rehash_node_delayed(proj); 2918 2919 proj->set_req(0, nullptr); // temporary disconnect 2920 ProjNode* proj2 = proj_clone(proj, iff); 2921 register_node(proj2, loop, iff, ddepth); 2922 2923 RegionNode* reg = new RegionNode(2); 2924 reg->set_req(1, proj2); 2925 register_node(reg, loop, iff, ddepth); 2926 2927 IfNode* dum_if = new IfNode(reg, short_circuit_if(nullptr, proj), iff->_prob, iff->_fcnt); 2928 register_node(dum_if, loop, reg, ddepth); 2929 2930 proj->set_req(0, dum_if); // reattach 2931 set_idom(proj, dum_if, ddepth); 2932 2933 ProjNode* dum_proj = proj_clone(other_proj, dum_if); 2934 register_node(dum_proj, loop, dum_if, ddepth); 2935 2936 return reg; 2937 } 2938 2939 //------------------------------ insert_cmpi_loop_exit ------------------------------------- 2940 // Clone a signed compare loop exit from an unsigned compare and 2941 // insert it before the unsigned cmp on the stay-in-loop path. 2942 // All new nodes inserted in the dominator tree between the original 2943 // if and it's projections. The original if test is replaced with 2944 // a constant to force the stay-in-loop path. 2945 // 2946 // This is done to make sure that the original if and it's projections 2947 // still dominate the same set of control nodes, that the ctrl() relation 2948 // from data nodes to them is preserved, and that their loop nesting is 2949 // preserved. 2950 // 2951 // before 2952 // if(i <u limit) unsigned compare loop exit 2953 // / | 2954 // v v 2955 // exit-proj stay-in-loop-proj 2956 // 2957 // after 2958 // if(stay-in-loop-const) original if 2959 // / | 2960 // / v 2961 // / if(i < limit) new signed test 2962 // / / | 2963 // / / v 2964 // / / if(i <u limit) new cloned unsigned test 2965 // / / / | 2966 // v v v | 2967 // region | 2968 // | | 2969 // dum-if | 2970 // / | | 2971 // ether | | 2972 // v v 2973 // exit-proj stay-in-loop-proj 2974 // 2975 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { 2976 const bool Signed = true; 2977 const bool Unsigned = false; 2978 2979 BoolNode* bol = if_cmpu->in(1)->as_Bool(); 2980 if (bol->_test._test != BoolTest::lt) return nullptr; 2981 CmpNode* cmpu = bol->in(1)->as_Cmp(); 2982 if (cmpu->Opcode() != Op_CmpU) return nullptr; 2983 int stride = stride_of_possible_iv(if_cmpu); 2984 if (stride == 0) return nullptr; 2985 2986 Node* lp_proj = stay_in_loop(if_cmpu, loop); 2987 guarantee(lp_proj != nullptr, "null loop node"); 2988 2989 ProjNode* lp_continue = lp_proj->as_Proj(); 2990 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); 2991 if (!lp_exit->is_IfFalse()) { 2992 // The loop exit condition is (i <u limit) ==> (i >= 0 && i < limit). 2993 // We therefore can't add a single exit condition. 2994 return nullptr; 2995 } 2996 // The loop exit condition is !(i <u limit) ==> (i < 0 || i >= limit). 2997 // Split out the exit condition (i < 0) for stride < 0 or (i >= limit) for stride > 0. 2998 Node* limit = nullptr; 2999 if (stride > 0) { 3000 limit = cmpu->in(2); 3001 } else { 3002 limit = _igvn.makecon(TypeInt::ZERO); 3003 set_ctrl(limit, C->root()); 3004 } 3005 // Create a new region on the exit path 3006 RegionNode* reg = insert_region_before_proj(lp_exit); 3007 guarantee(reg != nullptr, "null region node"); 3008 3009 // Clone the if-cmpu-true-false using a signed compare 3010 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; 3011 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); 3012 reg->add_req(cmpi_exit); 3013 3014 // Clone the if-cmpu-true-false 3015 BoolTest::mask rel_u = bol->_test._test; 3016 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); 3017 reg->add_req(cmpu_exit); 3018 3019 // Force original if to stay in loop. 3020 short_circuit_if(if_cmpu, lp_continue); 3021 3022 return cmpi_exit->in(0)->as_If(); 3023 } 3024 3025 //------------------------------ remove_cmpi_loop_exit ------------------------------------- 3026 // Remove a previously inserted signed compare loop exit. 3027 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { 3028 Node* lp_proj = stay_in_loop(if_cmp, loop); 3029 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && 3030 stay_in_loop(lp_proj, loop)->is_If() && 3031 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); 3032 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); 3033 set_ctrl(con, C->root()); 3034 if_cmp->set_req(1, con); 3035 } 3036 3037 //------------------------------ scheduled_nodelist ------------------------------------- 3038 // Create a post order schedule of nodes that are in the 3039 // "member" set. The list is returned in "sched". 3040 // The first node in "sched" is the loop head, followed by 3041 // nodes which have no inputs in the "member" set, and then 3042 // followed by the nodes that have an immediate input dependence 3043 // on a node in "sched". 3044 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { 3045 3046 assert(member.test(loop->_head->_idx), "loop head must be in member set"); 3047 VectorSet visited; 3048 Node_Stack nstack(loop->_body.size()); 3049 3050 Node* n = loop->_head; // top of stack is cached in "n" 3051 uint idx = 0; 3052 visited.set(n->_idx); 3053 3054 // Initially push all with no inputs from within member set 3055 for(uint i = 0; i < loop->_body.size(); i++ ) { 3056 Node *elt = loop->_body.at(i); 3057 if (member.test(elt->_idx)) { 3058 bool found = false; 3059 for (uint j = 0; j < elt->req(); j++) { 3060 Node* def = elt->in(j); 3061 if (def && member.test(def->_idx) && def != elt) { 3062 found = true; 3063 break; 3064 } 3065 } 3066 if (!found && elt != loop->_head) { 3067 nstack.push(n, idx); 3068 n = elt; 3069 assert(!visited.test(n->_idx), "not seen yet"); 3070 visited.set(n->_idx); 3071 } 3072 } 3073 } 3074 3075 // traverse out's that are in the member set 3076 while (true) { 3077 if (idx < n->outcnt()) { 3078 Node* use = n->raw_out(idx); 3079 idx++; 3080 if (!visited.test_set(use->_idx)) { 3081 if (member.test(use->_idx)) { 3082 nstack.push(n, idx); 3083 n = use; 3084 idx = 0; 3085 } 3086 } 3087 } else { 3088 // All outputs processed 3089 sched.push(n); 3090 if (nstack.is_empty()) break; 3091 n = nstack.node(); 3092 idx = nstack.index(); 3093 nstack.pop(); 3094 } 3095 } 3096 } 3097 3098 3099 //------------------------------ has_use_in_set ------------------------------------- 3100 // Has a use in the vector set 3101 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { 3102 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 3103 Node* use = n->fast_out(j); 3104 if (vset.test(use->_idx)) { 3105 return true; 3106 } 3107 } 3108 return false; 3109 } 3110 3111 3112 //------------------------------ has_use_internal_to_set ------------------------------------- 3113 // Has use internal to the vector set (ie. not in a phi at the loop head) 3114 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { 3115 Node* head = loop->_head; 3116 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 3117 Node* use = n->fast_out(j); 3118 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { 3119 return true; 3120 } 3121 } 3122 return false; 3123 } 3124 3125 3126 //------------------------------ clone_for_use_outside_loop ------------------------------------- 3127 // clone "n" for uses that are outside of loop 3128 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { 3129 int cloned = 0; 3130 assert(worklist.size() == 0, "should be empty"); 3131 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 3132 Node* use = n->fast_out(j); 3133 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { 3134 worklist.push(use); 3135 } 3136 } 3137 3138 if (C->check_node_count(worklist.size() + NodeLimitFudgeFactor, 3139 "Too many clones required in clone_for_use_outside_loop in partial peeling")) { 3140 return -1; 3141 } 3142 3143 while( worklist.size() ) { 3144 Node *use = worklist.pop(); 3145 if (!has_node(use) || use->in(0) == C->top()) continue; 3146 uint j; 3147 for (j = 0; j < use->req(); j++) { 3148 if (use->in(j) == n) break; 3149 } 3150 assert(j < use->req(), "must be there"); 3151 3152 // clone "n" and insert it between the inputs of "n" and the use outside the loop 3153 Node* n_clone = n->clone(); 3154 _igvn.replace_input_of(use, j, n_clone); 3155 cloned++; 3156 Node* use_c; 3157 if (!use->is_Phi()) { 3158 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); 3159 } else { 3160 // Use in a phi is considered a use in the associated predecessor block 3161 use_c = use->in(0)->in(j); 3162 } 3163 set_ctrl(n_clone, use_c); 3164 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); 3165 get_loop(use_c)->_body.push(n_clone); 3166 _igvn.register_new_node_with_optimizer(n_clone); 3167 #ifndef PRODUCT 3168 if (TracePartialPeeling) { 3169 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); 3170 } 3171 #endif 3172 } 3173 return cloned; 3174 } 3175 3176 3177 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- 3178 // clone "n" for special uses that are in the not_peeled region. 3179 // If these def-uses occur in separate blocks, the code generator 3180 // marks the method as not compilable. For example, if a "BoolNode" 3181 // is in a different basic block than the "IfNode" that uses it, then 3182 // the compilation is aborted in the code generator. 3183 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, 3184 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { 3185 if (n->is_Phi() || n->is_Load()) { 3186 return; 3187 } 3188 assert(worklist.size() == 0, "should be empty"); 3189 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 3190 Node* use = n->fast_out(j); 3191 if ( not_peel.test(use->_idx) && 3192 (use->is_If() || use->is_CMove() || use->is_Bool()) && 3193 use->in(1) == n) { 3194 worklist.push(use); 3195 } 3196 } 3197 if (worklist.size() > 0) { 3198 // clone "n" and insert it between inputs of "n" and the use 3199 Node* n_clone = n->clone(); 3200 loop->_body.push(n_clone); 3201 _igvn.register_new_node_with_optimizer(n_clone); 3202 set_ctrl(n_clone, get_ctrl(n)); 3203 sink_list.push(n_clone); 3204 not_peel.set(n_clone->_idx); 3205 #ifndef PRODUCT 3206 if (TracePartialPeeling) { 3207 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); 3208 } 3209 #endif 3210 while( worklist.size() ) { 3211 Node *use = worklist.pop(); 3212 _igvn.rehash_node_delayed(use); 3213 for (uint j = 1; j < use->req(); j++) { 3214 if (use->in(j) == n) { 3215 use->set_req(j, n_clone); 3216 } 3217 } 3218 } 3219 } 3220 } 3221 3222 3223 //------------------------------ insert_phi_for_loop ------------------------------------- 3224 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist 3225 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { 3226 Node *phi = PhiNode::make(lp, back_edge_val); 3227 phi->set_req(LoopNode::EntryControl, lp_entry_val); 3228 // Use existing phi if it already exists 3229 Node *hit = _igvn.hash_find_insert(phi); 3230 if( hit == nullptr ) { 3231 _igvn.register_new_node_with_optimizer(phi); 3232 set_ctrl(phi, lp); 3233 } else { 3234 // Remove the new phi from the graph and use the hit 3235 _igvn.remove_dead_node(phi); 3236 phi = hit; 3237 } 3238 _igvn.replace_input_of(use, idx, phi); 3239 } 3240 3241 #ifdef ASSERT 3242 //------------------------------ is_valid_loop_partition ------------------------------------- 3243 // Validate the loop partition sets: peel and not_peel 3244 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, 3245 VectorSet& not_peel ) { 3246 uint i; 3247 // Check that peel_list entries are in the peel set 3248 for (i = 0; i < peel_list.size(); i++) { 3249 if (!peel.test(peel_list.at(i)->_idx)) { 3250 return false; 3251 } 3252 } 3253 // Check at loop members are in one of peel set or not_peel set 3254 for (i = 0; i < loop->_body.size(); i++ ) { 3255 Node *def = loop->_body.at(i); 3256 uint di = def->_idx; 3257 // Check that peel set elements are in peel_list 3258 if (peel.test(di)) { 3259 if (not_peel.test(di)) { 3260 return false; 3261 } 3262 // Must be in peel_list also 3263 bool found = false; 3264 for (uint j = 0; j < peel_list.size(); j++) { 3265 if (peel_list.at(j)->_idx == di) { 3266 found = true; 3267 break; 3268 } 3269 } 3270 if (!found) { 3271 return false; 3272 } 3273 } else if (not_peel.test(di)) { 3274 if (peel.test(di)) { 3275 return false; 3276 } 3277 } else { 3278 return false; 3279 } 3280 } 3281 return true; 3282 } 3283 3284 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- 3285 // Ensure a use outside of loop is of the right form 3286 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { 3287 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 3288 return (use->is_Phi() && 3289 use_c->is_Region() && use_c->req() == 3 && 3290 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || 3291 use_c->in(exit_idx)->Opcode() == Op_IfFalse || 3292 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && 3293 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); 3294 } 3295 3296 //------------------------------ is_valid_clone_loop_form ------------------------------------- 3297 // Ensure that all uses outside of loop are of the right form 3298 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, 3299 uint orig_exit_idx, uint clone_exit_idx) { 3300 uint len = peel_list.size(); 3301 for (uint i = 0; i < len; i++) { 3302 Node *def = peel_list.at(i); 3303 3304 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 3305 Node *use = def->fast_out(j); 3306 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 3307 if (!loop->is_member(get_loop(use_c))) { 3308 // use is not in the loop, check for correct structure 3309 if (use->in(0) == def) { 3310 // Okay 3311 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { 3312 return false; 3313 } 3314 } 3315 } 3316 } 3317 return true; 3318 } 3319 #endif 3320 3321 //------------------------------ partial_peel ------------------------------------- 3322 // Partially peel (aka loop rotation) the top portion of a loop (called 3323 // the peel section below) by cloning it and placing one copy just before 3324 // the new loop head and the other copy at the bottom of the new loop. 3325 // 3326 // before after where it came from 3327 // 3328 // stmt1 stmt1 3329 // loop: stmt2 clone 3330 // stmt2 if condA goto exitA clone 3331 // if condA goto exitA new_loop: new 3332 // stmt3 stmt3 clone 3333 // if !condB goto loop if condB goto exitB clone 3334 // exitB: stmt2 orig 3335 // stmt4 if !condA goto new_loop orig 3336 // exitA: goto exitA 3337 // exitB: 3338 // stmt4 3339 // exitA: 3340 // 3341 // Step 1: find the cut point: an exit test on probable 3342 // induction variable. 3343 // Step 2: schedule (with cloning) operations in the peel 3344 // section that can be executed after the cut into 3345 // the section that is not peeled. This may need 3346 // to clone operations into exit blocks. For 3347 // instance, a reference to A[i] in the not-peel 3348 // section and a reference to B[i] in an exit block 3349 // may cause a left-shift of i by 2 to be placed 3350 // in the peel block. This step will clone the left 3351 // shift into the exit block and sink the left shift 3352 // from the peel to the not-peel section. 3353 // Step 3: clone the loop, retarget the control, and insert 3354 // phis for values that are live across the new loop 3355 // head. This is very dependent on the graph structure 3356 // from clone_loop. It creates region nodes for 3357 // exit control and associated phi nodes for values 3358 // flow out of the loop through that exit. The region 3359 // node is dominated by the clone's control projection. 3360 // So the clone's peel section is placed before the 3361 // new loop head, and the clone's not-peel section is 3362 // forms the top part of the new loop. The original 3363 // peel section forms the tail of the new loop. 3364 // Step 4: update the dominator tree and recompute the 3365 // dominator depth. 3366 // 3367 // orig 3368 // 3369 // stmt1 3370 // | 3371 // v 3372 // predicates 3373 // | 3374 // v 3375 // loop<----+ 3376 // | | 3377 // stmt2 | 3378 // | | 3379 // v | 3380 // ifA | 3381 // / | | 3382 // v v | 3383 // false true ^ <-- last_peel 3384 // / | | 3385 // / ===|==cut | 3386 // / stmt3 | <-- first_not_peel 3387 // / | | 3388 // | v | 3389 // v ifB | 3390 // exitA: / \ | 3391 // / \ | 3392 // v v | 3393 // false true | 3394 // / \ | 3395 // / ----+ 3396 // | 3397 // v 3398 // exitB: 3399 // stmt4 3400 // 3401 // 3402 // after clone loop 3403 // 3404 // stmt1 3405 // | 3406 // v 3407 // predicates 3408 // / \ 3409 // clone / \ orig 3410 // / \ 3411 // / \ 3412 // v v 3413 // +---->loop loop<----+ 3414 // | | | | 3415 // | stmt2 stmt2 | 3416 // | | | | 3417 // | v v | 3418 // | ifA ifA | 3419 // | | \ / | | 3420 // | v v v v | 3421 // ^ true false false true ^ <-- last_peel 3422 // | | ^ \ / | | 3423 // | cut==|== \ \ / ===|==cut | 3424 // | stmt3 \ \ / stmt3 | <-- first_not_peel 3425 // | | dom | | | | 3426 // | v \ 1v v2 v | 3427 // | ifB regionA ifB | 3428 // | / \ | / \ | 3429 // | / \ v / \ | 3430 // | v v exitA: v v | 3431 // | true false false true | 3432 // | / ^ \ / \ | 3433 // +---- \ \ / ----+ 3434 // dom \ / 3435 // \ 1v v2 3436 // regionB 3437 // | 3438 // v 3439 // exitB: 3440 // stmt4 3441 // 3442 // 3443 // after partial peel 3444 // 3445 // stmt1 3446 // | 3447 // v 3448 // predicates 3449 // / 3450 // clone / orig 3451 // / TOP 3452 // / \ 3453 // v v 3454 // TOP->loop loop----+ 3455 // | | | 3456 // stmt2 stmt2 | 3457 // | | | 3458 // v v | 3459 // ifA ifA | 3460 // | \ / | | 3461 // v v v v | 3462 // true false false true | <-- last_peel 3463 // | ^ \ / +------|---+ 3464 // +->newloop \ \ / === ==cut | | 3465 // | stmt3 \ \ / TOP | | 3466 // | | dom | | stmt3 | | <-- first_not_peel 3467 // | v \ 1v v2 v | | 3468 // | ifB regionA ifB ^ v 3469 // | / \ | / \ | | 3470 // | / \ v / \ | | 3471 // | v v exitA: v v | | 3472 // | true false false true | | 3473 // | / ^ \ / \ | | 3474 // | | \ \ / v | | 3475 // | | dom \ / TOP | | 3476 // | | \ 1v v2 | | 3477 // ^ v regionB | | 3478 // | | | | | 3479 // | | v ^ v 3480 // | | exitB: | | 3481 // | | stmt4 | | 3482 // | +------------>-----------------+ | 3483 // | | 3484 // +-----------------<---------------------+ 3485 // 3486 // 3487 // final graph 3488 // 3489 // stmt1 3490 // | 3491 // v 3492 // predicates 3493 // | 3494 // v 3495 // stmt2 clone 3496 // | 3497 // v 3498 // ........> ifA clone 3499 // : / | 3500 // dom / | 3501 // : v v 3502 // : false true 3503 // : | | 3504 // : | v 3505 // : | newloop<-----+ 3506 // : | | | 3507 // : | stmt3 clone | 3508 // : | | | 3509 // : | v | 3510 // : | ifB | 3511 // : | / \ | 3512 // : | v v | 3513 // : | false true | 3514 // : | | | | 3515 // : | v stmt2 | 3516 // : | exitB: | | 3517 // : | stmt4 v | 3518 // : | ifA orig | 3519 // : | / \ | 3520 // : | / \ | 3521 // : | v v | 3522 // : | false true | 3523 // : | / \ | 3524 // : v v -----+ 3525 // RegionA 3526 // | 3527 // v 3528 // exitA 3529 // 3530 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { 3531 3532 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only"); 3533 if (!loop->_head->is_Loop()) { 3534 return false; 3535 } 3536 LoopNode *head = loop->_head->as_Loop(); 3537 3538 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { 3539 return false; 3540 } 3541 3542 // Check for complex exit control 3543 for (uint ii = 0; ii < loop->_body.size(); ii++) { 3544 Node *n = loop->_body.at(ii); 3545 int opc = n->Opcode(); 3546 if (n->is_Call() || 3547 opc == Op_Catch || 3548 opc == Op_CatchProj || 3549 opc == Op_Jump || 3550 opc == Op_JumpProj) { 3551 #ifndef PRODUCT 3552 if (TracePartialPeeling) { 3553 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); 3554 } 3555 #endif 3556 return false; 3557 } 3558 } 3559 3560 int dd = dom_depth(head); 3561 3562 // Step 1: find cut point 3563 3564 // Walk up dominators to loop head looking for first loop exit 3565 // which is executed on every path thru loop. 3566 IfNode *peel_if = nullptr; 3567 IfNode *peel_if_cmpu = nullptr; 3568 3569 Node *iff = loop->tail(); 3570 while (iff != head) { 3571 if (iff->is_If()) { 3572 Node *ctrl = get_ctrl(iff->in(1)); 3573 if (ctrl->is_top()) return false; // Dead test on live IF. 3574 // If loop-varying exit-test, check for induction variable 3575 if (loop->is_member(get_loop(ctrl)) && 3576 loop->is_loop_exit(iff) && 3577 is_possible_iv_test(iff)) { 3578 Node* cmp = iff->in(1)->in(1); 3579 if (cmp->Opcode() == Op_CmpI) { 3580 peel_if = iff->as_If(); 3581 } else { 3582 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); 3583 peel_if_cmpu = iff->as_If(); 3584 } 3585 } 3586 } 3587 iff = idom(iff); 3588 } 3589 3590 // Prefer signed compare over unsigned compare. 3591 IfNode* new_peel_if = nullptr; 3592 if (peel_if == nullptr) { 3593 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == nullptr) { 3594 return false; // No peel point found 3595 } 3596 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); 3597 if (new_peel_if == nullptr) { 3598 return false; // No peel point found 3599 } 3600 peel_if = new_peel_if; 3601 } 3602 Node* last_peel = stay_in_loop(peel_if, loop); 3603 Node* first_not_peeled = stay_in_loop(last_peel, loop); 3604 if (first_not_peeled == nullptr || first_not_peeled == head) { 3605 return false; 3606 } 3607 3608 #ifndef PRODUCT 3609 if (TraceLoopOpts) { 3610 tty->print("PartialPeel "); 3611 loop->dump_head(); 3612 } 3613 3614 if (TracePartialPeeling) { 3615 tty->print_cr("before partial peel one iteration"); 3616 Node_List wl; 3617 Node* t = head->in(2); 3618 while (true) { 3619 wl.push(t); 3620 if (t == head) break; 3621 t = idom(t); 3622 } 3623 while (wl.size() > 0) { 3624 Node* tt = wl.pop(); 3625 tt->dump(); 3626 if (tt == last_peel) tty->print_cr("-- cut --"); 3627 } 3628 } 3629 #endif 3630 3631 C->print_method(PHASE_BEFORE_PARTIAL_PEELING, 4, head); 3632 3633 VectorSet peel; 3634 VectorSet not_peel; 3635 Node_List peel_list; 3636 Node_List worklist; 3637 Node_List sink_list; 3638 3639 uint estimate = loop->est_loop_clone_sz(1); 3640 if (exceeding_node_budget(estimate)) { 3641 return false; 3642 } 3643 3644 // Set of cfg nodes to peel are those that are executable from 3645 // the head through last_peel. 3646 assert(worklist.size() == 0, "should be empty"); 3647 worklist.push(head); 3648 peel.set(head->_idx); 3649 while (worklist.size() > 0) { 3650 Node *n = worklist.pop(); 3651 if (n != last_peel) { 3652 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 3653 Node* use = n->fast_out(j); 3654 if (use->is_CFG() && 3655 loop->is_member(get_loop(use)) && 3656 !peel.test_set(use->_idx)) { 3657 worklist.push(use); 3658 } 3659 } 3660 } 3661 } 3662 3663 // Set of non-cfg nodes to peel are those that are control 3664 // dependent on the cfg nodes. 3665 for (uint i = 0; i < loop->_body.size(); i++) { 3666 Node *n = loop->_body.at(i); 3667 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; 3668 if (peel.test(n_c->_idx)) { 3669 peel.set(n->_idx); 3670 } else { 3671 not_peel.set(n->_idx); 3672 } 3673 } 3674 3675 // Step 2: move operations from the peeled section down into the 3676 // not-peeled section 3677 3678 // Get a post order schedule of nodes in the peel region 3679 // Result in right-most operand. 3680 scheduled_nodelist(loop, peel, peel_list); 3681 3682 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 3683 3684 // For future check for too many new phis 3685 uint old_phi_cnt = 0; 3686 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { 3687 Node* use = head->fast_out(j); 3688 if (use->is_Phi()) old_phi_cnt++; 3689 } 3690 3691 #ifndef PRODUCT 3692 if (TracePartialPeeling) { 3693 tty->print_cr("\npeeled list"); 3694 } 3695 #endif 3696 3697 // Evacuate nodes in peel region into the not_peeled region if possible 3698 bool too_many_clones = false; 3699 uint new_phi_cnt = 0; 3700 uint cloned_for_outside_use = 0; 3701 for (uint i = 0; i < peel_list.size();) { 3702 Node* n = peel_list.at(i); 3703 #ifndef PRODUCT 3704 if (TracePartialPeeling) n->dump(); 3705 #endif 3706 bool incr = true; 3707 if (!n->is_CFG()) { 3708 if (has_use_in_set(n, not_peel)) { 3709 // If not used internal to the peeled region, 3710 // move "n" from peeled to not_peeled region. 3711 if (!has_use_internal_to_set(n, peel, loop)) { 3712 // if not pinned and not a load (which maybe anti-dependent on a store) 3713 // and not a CMove (Matcher expects only bool->cmove). 3714 if (n->in(0) == nullptr && !n->is_Load() && !n->is_CMove()) { 3715 int new_clones = clone_for_use_outside_loop(loop, n, worklist); 3716 if (C->failing()) return false; 3717 if (new_clones == -1) { 3718 too_many_clones = true; 3719 break; 3720 } 3721 cloned_for_outside_use += new_clones; 3722 sink_list.push(n); 3723 peel.remove(n->_idx); 3724 not_peel.set(n->_idx); 3725 peel_list.remove(i); 3726 incr = false; 3727 #ifndef PRODUCT 3728 if (TracePartialPeeling) { 3729 tty->print_cr("sink to not_peeled region: %d newbb: %d", 3730 n->_idx, get_ctrl(n)->_idx); 3731 } 3732 #endif 3733 } 3734 } else { 3735 // Otherwise check for special def-use cases that span 3736 // the peel/not_peel boundary such as bool->if 3737 clone_for_special_use_inside_loop(loop, n, not_peel, sink_list, worklist); 3738 new_phi_cnt++; 3739 } 3740 } 3741 } 3742 if (incr) i++; 3743 } 3744 3745 estimate += cloned_for_outside_use + new_phi_cnt; 3746 bool exceed_node_budget = !may_require_nodes(estimate); 3747 bool exceed_phi_limit = new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta; 3748 3749 if (too_many_clones || exceed_node_budget || exceed_phi_limit) { 3750 #ifndef PRODUCT 3751 if (TracePartialPeeling && exceed_phi_limit) { 3752 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", 3753 new_phi_cnt, old_phi_cnt, new_peel_if != nullptr?'T':'F'); 3754 } 3755 #endif 3756 if (new_peel_if != nullptr) { 3757 remove_cmpi_loop_exit(new_peel_if, loop); 3758 } 3759 // Inhibit more partial peeling on this loop 3760 assert(!head->is_partial_peel_loop(), "not partial peeled"); 3761 head->mark_partial_peel_failed(); 3762 if (cloned_for_outside_use > 0) { 3763 // Terminate this round of loop opts because 3764 // the graph outside this loop was changed. 3765 C->set_major_progress(); 3766 return true; 3767 } 3768 return false; 3769 } 3770 3771 // Step 3: clone loop, retarget control, and insert new phis 3772 3773 // Create new loop head for new phis and to hang 3774 // the nodes being moved (sinked) from the peel region. 3775 LoopNode* new_head = new LoopNode(last_peel, last_peel); 3776 new_head->set_unswitch_count(head->unswitch_count()); // Preserve 3777 _igvn.register_new_node_with_optimizer(new_head); 3778 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); 3779 _igvn.replace_input_of(first_not_peeled, 0, new_head); 3780 set_loop(new_head, loop); 3781 loop->_body.push(new_head); 3782 not_peel.set(new_head->_idx); 3783 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); 3784 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); 3785 3786 while (sink_list.size() > 0) { 3787 Node* n = sink_list.pop(); 3788 set_ctrl(n, new_head); 3789 } 3790 3791 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 3792 3793 clone_loop(loop, old_new, dd, IgnoreStripMined); 3794 3795 const uint clone_exit_idx = 1; 3796 const uint orig_exit_idx = 2; 3797 assert(is_valid_clone_loop_form(loop, peel_list, orig_exit_idx, clone_exit_idx), "bad clone loop"); 3798 3799 Node* head_clone = old_new[head->_idx]; 3800 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); 3801 Node* orig_tail_clone = head_clone->in(2); 3802 3803 // Add phi if "def" node is in peel set and "use" is not 3804 3805 for (uint i = 0; i < peel_list.size(); i++) { 3806 Node *def = peel_list.at(i); 3807 if (!def->is_CFG()) { 3808 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 3809 Node *use = def->fast_out(j); 3810 if (has_node(use) && use->in(0) != C->top() && 3811 (!peel.test(use->_idx) || 3812 (use->is_Phi() && use->in(0) == head)) ) { 3813 worklist.push(use); 3814 } 3815 } 3816 while( worklist.size() ) { 3817 Node *use = worklist.pop(); 3818 for (uint j = 1; j < use->req(); j++) { 3819 Node* n = use->in(j); 3820 if (n == def) { 3821 3822 // "def" is in peel set, "use" is not in peel set 3823 // or "use" is in the entry boundary (a phi) of the peel set 3824 3825 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; 3826 3827 if ( loop->is_member(get_loop( use_c )) ) { 3828 // use is in loop 3829 if (old_new[use->_idx] != nullptr) { // null for dead code 3830 Node* use_clone = old_new[use->_idx]; 3831 _igvn.replace_input_of(use, j, C->top()); 3832 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); 3833 } 3834 } else { 3835 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); 3836 // use is not in the loop, check if the live range includes the cut 3837 Node* lp_if = use_c->in(orig_exit_idx)->in(0); 3838 if (not_peel.test(lp_if->_idx)) { 3839 assert(j == orig_exit_idx, "use from original loop"); 3840 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); 3841 } 3842 } 3843 } 3844 } 3845 } 3846 } 3847 } 3848 3849 // Step 3b: retarget control 3850 3851 // Redirect control to the new loop head if a cloned node in 3852 // the not_peeled region has control that points into the peeled region. 3853 // This necessary because the cloned peeled region will be outside 3854 // the loop. 3855 // from to 3856 // cloned-peeled <---+ 3857 // new_head_clone: | <--+ 3858 // cloned-not_peeled in(0) in(0) 3859 // orig-peeled 3860 3861 for (uint i = 0; i < loop->_body.size(); i++) { 3862 Node *n = loop->_body.at(i); 3863 if (!n->is_CFG() && n->in(0) != nullptr && 3864 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { 3865 Node* n_clone = old_new[n->_idx]; 3866 _igvn.replace_input_of(n_clone, 0, new_head_clone); 3867 } 3868 } 3869 3870 // Backedge of the surviving new_head (the clone) is original last_peel 3871 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel); 3872 3873 // Cut first node in original not_peel set 3874 _igvn.rehash_node_delayed(new_head); // Multiple edge updates: 3875 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of 3876 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls 3877 3878 // Copy head_clone back-branch info to original head 3879 // and remove original head's loop entry and 3880 // clone head's back-branch 3881 _igvn.rehash_node_delayed(head); // Multiple edge updates 3882 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); 3883 head->set_req(LoopNode::LoopBackControl, C->top()); 3884 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top()); 3885 3886 // Similarly modify the phis 3887 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { 3888 Node* use = head->fast_out(k); 3889 if (use->is_Phi() && use->outcnt() > 0) { 3890 Node* use_clone = old_new[use->_idx]; 3891 _igvn.rehash_node_delayed(use); // Multiple edge updates 3892 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); 3893 use->set_req(LoopNode::LoopBackControl, C->top()); 3894 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top()); 3895 } 3896 } 3897 3898 // Step 4: update dominator tree and dominator depth 3899 3900 set_idom(head, orig_tail_clone, dd); 3901 recompute_dom_depth(); 3902 3903 // Inhibit more partial peeling on this loop 3904 new_head_clone->set_partial_peel_loop(); 3905 C->set_major_progress(); 3906 loop->record_for_igvn(); 3907 3908 #ifndef PRODUCT 3909 if (TracePartialPeeling) { 3910 tty->print_cr("\nafter partial peel one iteration"); 3911 Node_List wl; 3912 Node* t = last_peel; 3913 while (true) { 3914 wl.push(t); 3915 if (t == head_clone) break; 3916 t = idom(t); 3917 } 3918 while (wl.size() > 0) { 3919 Node* tt = wl.pop(); 3920 if (tt == head) tty->print_cr("orig head"); 3921 else if (tt == new_head_clone) tty->print_cr("new head"); 3922 else if (tt == head_clone) tty->print_cr("clone head"); 3923 tt->dump(); 3924 } 3925 } 3926 #endif 3927 3928 C->print_method(PHASE_AFTER_PARTIAL_PEELING, 4, new_head_clone); 3929 3930 return true; 3931 } 3932 3933 // Transform: 3934 // 3935 // loop<-----------------+ 3936 // | | 3937 // stmt1 stmt2 .. stmtn | 3938 // | | | | 3939 // \ | / | 3940 // v v v | 3941 // region | 3942 // | | 3943 // shared_stmt | 3944 // | | 3945 // v | 3946 // if | 3947 // / \ | 3948 // | -----------+ 3949 // v 3950 // 3951 // into: 3952 // 3953 // loop<-------------------+ 3954 // | | 3955 // v | 3956 // +->loop | 3957 // | | | 3958 // | stmt1 stmt2 .. stmtn | 3959 // | | | | | 3960 // | | \ / | 3961 // | | v v | 3962 // | | region1 | 3963 // | | | | 3964 // | shared_stmt shared_stmt | 3965 // | | | | 3966 // | v v | 3967 // | if if | 3968 // | /\ / \ | 3969 // +-- | | -------+ 3970 // \ / 3971 // v v 3972 // region2 3973 // 3974 // (region2 is shown to merge mirrored projections of the loop exit 3975 // ifs to make the diagram clearer but they really merge the same 3976 // projection) 3977 // 3978 // Conditions for this transformation to trigger: 3979 // - the path through stmt1 is frequent enough 3980 // - the inner loop will be turned into a counted loop after transformation 3981 bool PhaseIdealLoop::duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old_new) { 3982 if (!DuplicateBackedge) { 3983 return false; 3984 } 3985 assert(!loop->_head->is_CountedLoop() || StressDuplicateBackedge, "Non-counted loop only"); 3986 if (!loop->_head->is_Loop()) { 3987 return false; 3988 } 3989 3990 uint estimate = loop->est_loop_clone_sz(1); 3991 if (exceeding_node_budget(estimate)) { 3992 return false; 3993 } 3994 3995 LoopNode *head = loop->_head->as_Loop(); 3996 3997 Node* region = nullptr; 3998 IfNode* exit_test = nullptr; 3999 uint inner; 4000 float f; 4001 if (StressDuplicateBackedge) { 4002 if (head->is_strip_mined()) { 4003 return false; 4004 } 4005 Node* c = head->in(LoopNode::LoopBackControl); 4006 4007 while (c != head) { 4008 if (c->is_Region()) { 4009 region = c; 4010 } 4011 c = idom(c); 4012 } 4013 4014 if (region == nullptr) { 4015 return false; 4016 } 4017 4018 inner = 1; 4019 } else { 4020 // Is the shape of the loop that of a counted loop... 4021 Node* back_control = loop_exit_control(head, loop); 4022 if (back_control == nullptr) { 4023 return false; 4024 } 4025 4026 BoolTest::mask bt = BoolTest::illegal; 4027 float cl_prob = 0; 4028 Node* incr = nullptr; 4029 Node* limit = nullptr; 4030 Node* cmp = loop_exit_test(back_control, loop, incr, limit, bt, cl_prob); 4031 if (cmp == nullptr || cmp->Opcode() != Op_CmpI) { 4032 return false; 4033 } 4034 4035 // With an extra phi for the candidate iv? 4036 // Or the region node is the loop head 4037 if (!incr->is_Phi() || incr->in(0) == head) { 4038 return false; 4039 } 4040 4041 PathFrequency pf(head, this); 4042 region = incr->in(0); 4043 4044 // Go over all paths for the extra phi's region and see if that 4045 // path is frequent enough and would match the expected iv shape 4046 // if the extra phi is removed 4047 inner = 0; 4048 for (uint i = 1; i < incr->req(); ++i) { 4049 Node* in = incr->in(i); 4050 Node* trunc1 = nullptr; 4051 Node* trunc2 = nullptr; 4052 const TypeInteger* iv_trunc_t = nullptr; 4053 Node* orig_in = in; 4054 if (!(in = CountedLoopNode::match_incr_with_optional_truncation(in, &trunc1, &trunc2, &iv_trunc_t, T_INT))) { 4055 continue; 4056 } 4057 assert(in->Opcode() == Op_AddI, "wrong increment code"); 4058 Node* xphi = nullptr; 4059 Node* stride = loop_iv_stride(in, loop, xphi); 4060 4061 if (stride == nullptr) { 4062 continue; 4063 } 4064 4065 PhiNode* phi = loop_iv_phi(xphi, nullptr, head, loop); 4066 if (phi == nullptr || 4067 (trunc1 == nullptr && phi->in(LoopNode::LoopBackControl) != incr) || 4068 (trunc1 != nullptr && phi->in(LoopNode::LoopBackControl) != trunc1)) { 4069 return false; 4070 } 4071 4072 f = pf.to(region->in(i)); 4073 if (f > 0.5) { 4074 inner = i; 4075 break; 4076 } 4077 } 4078 4079 if (inner == 0) { 4080 return false; 4081 } 4082 4083 exit_test = back_control->in(0)->as_If(); 4084 } 4085 4086 if (idom(region)->is_Catch()) { 4087 return false; 4088 } 4089 4090 // Collect all control nodes that need to be cloned (shared_stmt in the diagram) 4091 Unique_Node_List wq; 4092 wq.push(head->in(LoopNode::LoopBackControl)); 4093 for (uint i = 0; i < wq.size(); i++) { 4094 Node* c = wq.at(i); 4095 assert(get_loop(c) == loop, "not in the right loop?"); 4096 if (c->is_Region()) { 4097 if (c != region) { 4098 for (uint j = 1; j < c->req(); ++j) { 4099 wq.push(c->in(j)); 4100 } 4101 } 4102 } else { 4103 wq.push(c->in(0)); 4104 } 4105 assert(!is_dominator(c, region) || c == region, "shouldn't go above region"); 4106 } 4107 4108 Node* region_dom = idom(region); 4109 4110 // Can't do the transformation if this would cause a membar pair to 4111 // be split 4112 for (uint i = 0; i < wq.size(); i++) { 4113 Node* c = wq.at(i); 4114 if (c->is_MemBar() && (c->as_MemBar()->trailing_store() || c->as_MemBar()->trailing_load_store())) { 4115 assert(c->as_MemBar()->leading_membar()->trailing_membar() == c, "bad membar pair"); 4116 if (!wq.member(c->as_MemBar()->leading_membar())) { 4117 return false; 4118 } 4119 } 4120 } 4121 4122 // Collect data nodes that need to be clones as well 4123 int dd = dom_depth(head); 4124 4125 for (uint i = 0; i < loop->_body.size(); ++i) { 4126 Node* n = loop->_body.at(i); 4127 if (has_ctrl(n)) { 4128 Node* c = get_ctrl(n); 4129 if (wq.member(c)) { 4130 wq.push(n); 4131 } 4132 } else { 4133 set_idom(n, idom(n), dd); 4134 } 4135 } 4136 4137 // clone shared_stmt 4138 clone_loop_body(wq, old_new, nullptr); 4139 4140 Node* region_clone = old_new[region->_idx]; 4141 region_clone->set_req(inner, C->top()); 4142 set_idom(region, region->in(inner), dd); 4143 4144 // Prepare the outer loop 4145 Node* outer_head = new LoopNode(head->in(LoopNode::EntryControl), old_new[head->in(LoopNode::LoopBackControl)->_idx]); 4146 register_control(outer_head, loop->_parent, outer_head->in(LoopNode::EntryControl)); 4147 _igvn.replace_input_of(head, LoopNode::EntryControl, outer_head); 4148 set_idom(head, outer_head, dd); 4149 4150 fix_body_edges(wq, loop, old_new, dd, loop->_parent, true); 4151 4152 // Make one of the shared_stmt copies only reachable from stmt1, the 4153 // other only from stmt2..stmtn. 4154 Node* dom = nullptr; 4155 for (uint i = 1; i < region->req(); ++i) { 4156 if (i != inner) { 4157 _igvn.replace_input_of(region, i, C->top()); 4158 } 4159 Node* in = region_clone->in(i); 4160 if (in->is_top()) { 4161 continue; 4162 } 4163 if (dom == nullptr) { 4164 dom = in; 4165 } else { 4166 dom = dom_lca(dom, in); 4167 } 4168 } 4169 4170 set_idom(region_clone, dom, dd); 4171 4172 // Set up the outer loop 4173 for (uint i = 0; i < head->outcnt(); i++) { 4174 Node* u = head->raw_out(i); 4175 if (u->is_Phi()) { 4176 Node* outer_phi = u->clone(); 4177 outer_phi->set_req(0, outer_head); 4178 Node* backedge = old_new[u->in(LoopNode::LoopBackControl)->_idx]; 4179 if (backedge == nullptr) { 4180 backedge = u->in(LoopNode::LoopBackControl); 4181 } 4182 outer_phi->set_req(LoopNode::LoopBackControl, backedge); 4183 register_new_node(outer_phi, outer_head); 4184 _igvn.replace_input_of(u, LoopNode::EntryControl, outer_phi); 4185 } 4186 } 4187 4188 // create control and data nodes for out of loop uses (including region2) 4189 Node_List worklist; 4190 uint new_counter = C->unique(); 4191 fix_ctrl_uses(wq, loop, old_new, ControlAroundStripMined, outer_head, nullptr, worklist); 4192 4193 Node_List *split_if_set = nullptr; 4194 Node_List *split_bool_set = nullptr; 4195 Node_List *split_cex_set = nullptr; 4196 fix_data_uses(wq, loop, ControlAroundStripMined, head->is_strip_mined() ? loop->_parent : loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set); 4197 4198 finish_clone_loop(split_if_set, split_bool_set, split_cex_set); 4199 4200 if (exit_test != nullptr) { 4201 float cnt = exit_test->_fcnt; 4202 if (cnt != COUNT_UNKNOWN) { 4203 exit_test->_fcnt = cnt * f; 4204 old_new[exit_test->_idx]->as_If()->_fcnt = cnt * (1 - f); 4205 } 4206 } 4207 4208 C->set_major_progress(); 4209 4210 return true; 4211 } 4212 4213 // AutoVectorize the loop: replace scalar ops with vector ops. 4214 PhaseIdealLoop::AutoVectorizeStatus 4215 PhaseIdealLoop::auto_vectorize(IdealLoopTree* lpt, VSharedData &vshared) { 4216 // Counted loop only 4217 if (!lpt->is_counted()) { 4218 return AutoVectorizeStatus::Impossible; 4219 } 4220 4221 // Main-loop only 4222 CountedLoopNode* cl = lpt->_head->as_CountedLoop(); 4223 if (!cl->is_main_loop()) { 4224 return AutoVectorizeStatus::Impossible; 4225 } 4226 4227 VLoop vloop(lpt, false); 4228 if (!vloop.check_preconditions()) { 4229 return AutoVectorizeStatus::TriedAndFailed; 4230 } 4231 4232 // Ensure the shared data is cleared before each use 4233 vshared.clear(); 4234 4235 SuperWord sw(vloop, vshared); 4236 if (!sw.transform_loop()) { 4237 return AutoVectorizeStatus::TriedAndFailed; 4238 } 4239 4240 return AutoVectorizeStatus::Success; 4241 } 4242 4243 // Having ReductionNodes in the loop is expensive. They need to recursively 4244 // fold together the vector values, for every vectorized loop iteration. If 4245 // we encounter the following pattern, we can vector accumulate the values 4246 // inside the loop, and only have a single UnorderedReduction after the loop. 4247 // 4248 // CountedLoop init 4249 // | | 4250 // +------+ | +-----------------------+ 4251 // | | | | 4252 // PhiNode (s) | 4253 // | | 4254 // | Vector | 4255 // | | | 4256 // UnorderedReduction (first_ur) | 4257 // | | 4258 // ... Vector | 4259 // | | | 4260 // UnorderedReduction (last_ur) | 4261 // | | 4262 // +---------------------+ 4263 // 4264 // We patch the graph to look like this: 4265 // 4266 // CountedLoop identity_vector 4267 // | | 4268 // +-------+ | +---------------+ 4269 // | | | | 4270 // PhiNode (v) | 4271 // | | 4272 // | Vector | 4273 // | | | 4274 // VectorAccumulator | 4275 // | | 4276 // ... Vector | 4277 // | | | 4278 // init VectorAccumulator | 4279 // | | | | 4280 // UnorderedReduction +-----------+ 4281 // 4282 // We turned the scalar (s) Phi into a vectorized one (v). In the loop, we 4283 // use vector_accumulators, which do the same reductions, but only element 4284 // wise. This is a single operation per vector_accumulator, rather than many 4285 // for a UnorderedReduction. We can then reduce the last vector_accumulator 4286 // after the loop, and also reduce the init value into it. 4287 // We can not do this with all reductions. Some reductions do not allow the 4288 // reordering of operations (for example float addition). 4289 void PhaseIdealLoop::move_unordered_reduction_out_of_loop(IdealLoopTree* loop) { 4290 assert(!C->major_progress() && loop->is_counted() && loop->is_innermost(), "sanity"); 4291 4292 // Find all Phi nodes with UnorderedReduction on backedge. 4293 CountedLoopNode* cl = loop->_head->as_CountedLoop(); 4294 for (DUIterator_Fast jmax, j = cl->fast_outs(jmax); j < jmax; j++) { 4295 Node* phi = cl->fast_out(j); 4296 // We have a phi with a single use, and a UnorderedReduction on the backedge. 4297 if (!phi->is_Phi() || phi->outcnt() != 1 || !phi->in(2)->is_UnorderedReduction()) { 4298 continue; 4299 } 4300 4301 UnorderedReductionNode* last_ur = phi->in(2)->as_UnorderedReduction(); 4302 4303 // Determine types 4304 const TypeVect* vec_t = last_ur->vect_type(); 4305 uint vector_length = vec_t->length(); 4306 BasicType bt = vec_t->element_basic_type(); 4307 const Type* bt_t = Type::get_const_basic_type(bt); 4308 4309 // Convert opcode from vector-reduction -> scalar -> normal-vector-op 4310 const int sopc = VectorNode::scalar_opcode(last_ur->Opcode(), bt); 4311 const int vopc = VectorNode::opcode(sopc, bt); 4312 if (!Matcher::match_rule_supported_vector(vopc, vector_length, bt)) { 4313 DEBUG_ONLY( last_ur->dump(); ) 4314 assert(false, "do not have normal vector op for this reduction"); 4315 continue; // not implemented -> fails 4316 } 4317 4318 // Traverse up the chain of UnorderedReductions, checking that it loops back to 4319 // the phi. Check that all UnorderedReductions only have a single use, except for 4320 // the last (last_ur), which only has phi as a use in the loop, and all other uses 4321 // are outside the loop. 4322 UnorderedReductionNode* current = last_ur; 4323 UnorderedReductionNode* first_ur = nullptr; 4324 while (true) { 4325 assert(current->is_UnorderedReduction(), "sanity"); 4326 4327 // Expect no ctrl and a vector_input from within the loop. 4328 Node* ctrl = current->in(0); 4329 Node* vector_input = current->in(2); 4330 if (ctrl != nullptr || get_ctrl(vector_input) != cl) { 4331 DEBUG_ONLY( current->dump(1); ) 4332 assert(false, "reduction has ctrl or bad vector_input"); 4333 break; // Chain traversal fails. 4334 } 4335 4336 assert(current->vect_type() != nullptr, "must have vector type"); 4337 if (current->vect_type() != last_ur->vect_type()) { 4338 // Reductions do not have the same vector type (length and element type). 4339 break; // Chain traversal fails. 4340 } 4341 4342 // Expect single use of UnorderedReduction, except for last_ur. 4343 if (current == last_ur) { 4344 // Expect all uses to be outside the loop, except phi. 4345 for (DUIterator_Fast kmax, k = current->fast_outs(kmax); k < kmax; k++) { 4346 Node* use = current->fast_out(k); 4347 if (use != phi && ctrl_or_self(use) == cl) { 4348 DEBUG_ONLY( current->dump(-1); ) 4349 assert(false, "reduction has use inside loop"); 4350 // Should not be allowed by SuperWord::mark_reductions 4351 return; // bail out of optimization 4352 } 4353 } 4354 } else { 4355 if (current->outcnt() != 1) { 4356 break; // Chain traversal fails. 4357 } 4358 } 4359 4360 // Expect another UnorderedReduction or phi as the scalar input. 4361 Node* scalar_input = current->in(1); 4362 if (scalar_input->is_UnorderedReduction() && 4363 scalar_input->Opcode() == current->Opcode()) { 4364 // Move up the UnorderedReduction chain. 4365 current = scalar_input->as_UnorderedReduction(); 4366 } else if (scalar_input == phi) { 4367 // Chain terminates at phi. 4368 first_ur = current; 4369 current = nullptr; 4370 break; // Success. 4371 } else { 4372 // scalar_input is neither phi nor a matching reduction 4373 // Can for example be scalar reduction when we have 4374 // partial vectorization. 4375 break; // Chain traversal fails. 4376 } 4377 } 4378 if (current != nullptr) { 4379 // Chain traversal was not successful. 4380 continue; 4381 } 4382 assert(first_ur != nullptr, "must have successfully terminated chain traversal"); 4383 4384 Node* identity_scalar = ReductionNode::make_identity_con_scalar(_igvn, sopc, bt); 4385 set_ctrl(identity_scalar, C->root()); 4386 VectorNode* identity_vector = VectorNode::scalar2vector(identity_scalar, vector_length, bt_t); 4387 register_new_node(identity_vector, C->root()); 4388 assert(vec_t == identity_vector->vect_type(), "matching vector type"); 4389 VectorNode::trace_new_vector(identity_vector, "UnorderedReduction"); 4390 4391 // Turn the scalar phi into a vector phi. 4392 _igvn.rehash_node_delayed(phi); 4393 Node* init = phi->in(1); // Remember init before replacing it. 4394 phi->set_req_X(1, identity_vector, &_igvn); 4395 phi->as_Type()->set_type(vec_t); 4396 _igvn.set_type(phi, vec_t); 4397 4398 // Traverse down the chain of UnorderedReductions, and replace them with vector_accumulators. 4399 current = first_ur; 4400 while (true) { 4401 // Create vector_accumulator to replace current. 4402 Node* last_vector_accumulator = current->in(1); 4403 Node* vector_input = current->in(2); 4404 VectorNode* vector_accumulator = VectorNode::make(vopc, last_vector_accumulator, vector_input, vec_t); 4405 register_new_node(vector_accumulator, cl); 4406 _igvn.replace_node(current, vector_accumulator); 4407 VectorNode::trace_new_vector(vector_accumulator, "UnorderedReduction"); 4408 if (current == last_ur) { 4409 break; 4410 } 4411 current = vector_accumulator->unique_out()->as_UnorderedReduction(); 4412 } 4413 4414 // Create post-loop reduction. 4415 Node* last_accumulator = phi->in(2); 4416 Node* post_loop_reduction = ReductionNode::make(sopc, nullptr, init, last_accumulator, bt); 4417 4418 // Take over uses of last_accumulator that are not in the loop. 4419 for (DUIterator i = last_accumulator->outs(); last_accumulator->has_out(i); i++) { 4420 Node* use = last_accumulator->out(i); 4421 if (use != phi && use != post_loop_reduction) { 4422 assert(ctrl_or_self(use) != cl, "use must be outside loop"); 4423 use->replace_edge(last_accumulator, post_loop_reduction, &_igvn); 4424 --i; 4425 } 4426 } 4427 register_new_node(post_loop_reduction, get_late_ctrl(post_loop_reduction, cl)); 4428 VectorNode::trace_new_vector(post_loop_reduction, "UnorderedReduction"); 4429 4430 assert(last_accumulator->outcnt() == 2, "last_accumulator has 2 uses: phi and post_loop_reduction"); 4431 assert(post_loop_reduction->outcnt() > 0, "should have taken over all non loop uses of last_accumulator"); 4432 assert(phi->outcnt() == 1, "accumulator is the only use of phi"); 4433 } 4434 }