1 /* 2 * Copyright (c) 1999, 2017, 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 "memory/allocation.inline.hpp" 27 #include "memory/resourceArea.hpp" 28 #include "opto/addnode.hpp" 29 #include "opto/castnode.hpp" 30 #include "opto/connode.hpp" 31 #include "opto/castnode.hpp" 32 #include "opto/divnode.hpp" 33 #include "opto/loopnode.hpp" 34 #include "opto/matcher.hpp" 35 #include "opto/mulnode.hpp" 36 #include "opto/movenode.hpp" 37 #include "opto/opaquenode.hpp" 38 #include "opto/rootnode.hpp" 39 #include "opto/subnode.hpp" 40 41 //============================================================================= 42 //------------------------------split_thru_phi--------------------------------- 43 // Split Node 'n' through merge point if there is enough win. 44 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { 45 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { 46 // ConvI2L may have type information on it which is unsafe to push up 47 // so disable this for now 48 return NULL; 49 } 50 51 // Splitting range check CastIIs through a loop induction Phi can 52 // cause new Phis to be created that are left unrelated to the loop 53 // induction Phi and prevent optimizations (vectorization) 54 if (n->Opcode() == Op_CastII && n->as_CastII()->has_range_check() && 55 region->is_CountedLoop() && n->in(1) == region->as_CountedLoop()->phi()) { 56 return NULL; 57 } 58 59 int wins = 0; 60 assert(!n->is_CFG(), ""); 61 assert(region->is_Region(), ""); 62 63 const Type* type = n->bottom_type(); 64 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); 65 Node *phi; 66 if (t_oop != NULL && t_oop->is_known_instance_field()) { 67 int iid = t_oop->instance_id(); 68 int index = C->get_alias_index(t_oop); 69 int offset = t_oop->offset(); 70 phi = new PhiNode(region, type, NULL, iid, index, offset); 71 } else { 72 phi = PhiNode::make_blank(region, n); 73 } 74 uint old_unique = C->unique(); 75 for (uint i = 1; i < region->req(); i++) { 76 Node *x; 77 Node* the_clone = NULL; 78 if (region->in(i) == C->top()) { 79 x = C->top(); // Dead path? Use a dead data op 80 } else { 81 x = n->clone(); // Else clone up the data op 82 the_clone = x; // Remember for possible deletion. 83 // Alter data node to use pre-phi inputs 84 if (n->in(0) == region) 85 x->set_req( 0, region->in(i) ); 86 for (uint j = 1; j < n->req(); j++) { 87 Node *in = n->in(j); 88 if (in->is_Phi() && in->in(0) == region) 89 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone 90 } 91 } 92 // Check for a 'win' on some paths 93 const Type *t = x->Value(&_igvn); 94 95 bool singleton = t->singleton(); 96 97 // A TOP singleton indicates that there are no possible values incoming 98 // along a particular edge. In most cases, this is OK, and the Phi will 99 // be eliminated later in an Ideal call. However, we can't allow this to 100 // happen if the singleton occurs on loop entry, as the elimination of 101 // the PhiNode may cause the resulting node to migrate back to a previous 102 // loop iteration. 103 if (singleton && t == Type::TOP) { 104 // Is_Loop() == false does not confirm the absence of a loop (e.g., an 105 // irreducible loop may not be indicated by an affirmative is_Loop()); 106 // therefore, the only top we can split thru a phi is on a backedge of 107 // a loop. 108 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); 109 } 110 111 if (singleton) { 112 wins++; 113 x = ((PhaseGVN&)_igvn).makecon(t); 114 } else { 115 // We now call Identity to try to simplify the cloned node. 116 // Note that some Identity methods call phase->type(this). 117 // Make sure that the type array is big enough for 118 // our new node, even though we may throw the node away. 119 // (Note: This tweaking with igvn only works because x is a new node.) 120 _igvn.set_type(x, t); 121 // If x is a TypeNode, capture any more-precise type permanently into Node 122 // otherwise it will be not updated during igvn->transform since 123 // igvn->type(x) is set to x->Value() already. 124 x->raise_bottom_type(t); 125 Node *y = x->Identity(&_igvn); 126 if (y != x) { 127 wins++; 128 x = y; 129 } else { 130 y = _igvn.hash_find(x); 131 if (y) { 132 wins++; 133 x = y; 134 } else { 135 // Else x is a new node we are keeping 136 // We do not need register_new_node_with_optimizer 137 // because set_type has already been called. 138 _igvn._worklist.push(x); 139 } 140 } 141 } 142 if (x != the_clone && the_clone != NULL) 143 _igvn.remove_dead_node(the_clone); 144 phi->set_req( i, x ); 145 } 146 // Too few wins? 147 if (wins <= policy) { 148 _igvn.remove_dead_node(phi); 149 return NULL; 150 } 151 152 // Record Phi 153 register_new_node( phi, region ); 154 155 for (uint i2 = 1; i2 < phi->req(); i2++) { 156 Node *x = phi->in(i2); 157 // If we commoned up the cloned 'x' with another existing Node, 158 // the existing Node picks up a new use. We need to make the 159 // existing Node occur higher up so it dominates its uses. 160 Node *old_ctrl; 161 IdealLoopTree *old_loop; 162 163 if (x->is_Con()) { 164 // Constant's control is always root. 165 set_ctrl(x, C->root()); 166 continue; 167 } 168 // The occasional new node 169 if (x->_idx >= old_unique) { // Found a new, unplaced node? 170 old_ctrl = NULL; 171 old_loop = NULL; // Not in any prior loop 172 } else { 173 old_ctrl = get_ctrl(x); 174 old_loop = get_loop(old_ctrl); // Get prior loop 175 } 176 // New late point must dominate new use 177 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2)); 178 if (new_ctrl == old_ctrl) // Nothing is changed 179 continue; 180 181 IdealLoopTree *new_loop = get_loop(new_ctrl); 182 183 // Don't move x into a loop if its uses are 184 // outside of loop. Otherwise x will be cloned 185 // for each use outside of this loop. 186 IdealLoopTree *use_loop = get_loop(region); 187 if (!new_loop->is_member(use_loop) && 188 (old_loop == NULL || !new_loop->is_member(old_loop))) { 189 // Take early control, later control will be recalculated 190 // during next iteration of loop optimizations. 191 new_ctrl = get_early_ctrl(x); 192 new_loop = get_loop(new_ctrl); 193 } 194 // Set new location 195 set_ctrl(x, new_ctrl); 196 // If changing loop bodies, see if we need to collect into new body 197 if (old_loop != new_loop) { 198 if (old_loop && !old_loop->_child) 199 old_loop->_body.yank(x); 200 if (!new_loop->_child) 201 new_loop->_body.push(x); // Collect body info 202 } 203 } 204 205 return phi; 206 } 207 208 //------------------------------dominated_by------------------------------------ 209 // Replace the dominated test with an obvious true or false. Place it on the 210 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the 211 // live path up to the dominating control. 212 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) { 213 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); } 214 215 // prevdom is the dominating projection of the dominating test. 216 assert( iff->is_If(), "" ); 217 assert(iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd || iff->Opcode() == Op_RangeCheck, "Check this code when new subtype is added"); 218 int pop = prevdom->Opcode(); 219 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); 220 if (flip) { 221 if (pop == Op_IfTrue) 222 pop = Op_IfFalse; 223 else 224 pop = Op_IfTrue; 225 } 226 // 'con' is set to true or false to kill the dominated test. 227 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); 228 set_ctrl(con, C->root()); // Constant gets a new use 229 // Hack the dominated test 230 _igvn.replace_input_of(iff, 1, con); 231 232 // If I dont have a reachable TRUE and FALSE path following the IfNode then 233 // I can assume this path reaches an infinite loop. In this case it's not 234 // important to optimize the data Nodes - either the whole compilation will 235 // be tossed or this path (and all data Nodes) will go dead. 236 if (iff->outcnt() != 2) return; 237 238 // Make control-dependent data Nodes on the live path (path that will remain 239 // once the dominated IF is removed) become control-dependent on the 240 // dominating projection. 241 Node* dp = iff->as_If()->proj_out(pop == Op_IfTrue); 242 243 // Loop predicates may have depending checks which should not 244 // be skipped. For example, range check predicate has two checks 245 // for lower and upper bounds. 246 if (dp == NULL) 247 return; 248 249 ProjNode* dp_proj = dp->as_Proj(); 250 ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj(); 251 if (exclude_loop_predicate && 252 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL || 253 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) { 254 // If this is a range check (IfNode::is_range_check), do not 255 // reorder because Compile::allow_range_check_smearing might have 256 // changed the check. 257 return; // Let IGVN transformation change control dependence. 258 } 259 260 IdealLoopTree *old_loop = get_loop(dp); 261 262 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { 263 Node* cd = dp->fast_out(i); // Control-dependent node 264 if (cd->depends_only_on_test()) { 265 assert(cd->in(0) == dp, ""); 266 _igvn.replace_input_of(cd, 0, prevdom); 267 set_early_ctrl(cd); 268 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); 269 if (old_loop != new_loop) { 270 if (!old_loop->_child) old_loop->_body.yank(cd); 271 if (!new_loop->_child) new_loop->_body.push(cd); 272 } 273 --i; 274 --imax; 275 } 276 } 277 } 278 279 //------------------------------has_local_phi_input---------------------------- 280 // Return TRUE if 'n' has Phi inputs from its local block and no other 281 // block-local inputs (all non-local-phi inputs come from earlier blocks) 282 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { 283 Node *n_ctrl = get_ctrl(n); 284 // See if some inputs come from a Phi in this block, or from before 285 // this block. 286 uint i; 287 for( i = 1; i < n->req(); i++ ) { 288 Node *phi = n->in(i); 289 if( phi->is_Phi() && phi->in(0) == n_ctrl ) 290 break; 291 } 292 if( i >= n->req() ) 293 return NULL; // No Phi inputs; nowhere to clone thru 294 295 // Check for inputs created between 'n' and the Phi input. These 296 // must split as well; they have already been given the chance 297 // (courtesy of a post-order visit) and since they did not we must 298 // recover the 'cost' of splitting them by being very profitable 299 // when splitting 'n'. Since this is unlikely we simply give up. 300 for( i = 1; i < n->req(); i++ ) { 301 Node *m = n->in(i); 302 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { 303 // We allow the special case of AddP's with no local inputs. 304 // This allows us to split-up address expressions. 305 if (m->is_AddP() && 306 get_ctrl(m->in(2)) != n_ctrl && 307 get_ctrl(m->in(3)) != n_ctrl) { 308 // Move the AddP up to dominating point 309 set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); 310 continue; 311 } 312 return NULL; 313 } 314 assert(m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control"); 315 } 316 317 return n_ctrl; 318 } 319 320 //------------------------------remix_address_expressions---------------------- 321 // Rework addressing expressions to get the most loop-invariant stuff 322 // moved out. We'd like to do all associative operators, but it's especially 323 // important (common) to do address expressions. 324 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { 325 if (!has_ctrl(n)) return NULL; 326 Node *n_ctrl = get_ctrl(n); 327 IdealLoopTree *n_loop = get_loop(n_ctrl); 328 329 // See if 'n' mixes loop-varying and loop-invariant inputs and 330 // itself is loop-varying. 331 332 // Only interested in binary ops (and AddP) 333 if( n->req() < 3 || n->req() > 4 ) return NULL; 334 335 Node *n1_ctrl = get_ctrl(n->in( 1)); 336 Node *n2_ctrl = get_ctrl(n->in( 2)); 337 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); 338 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); 339 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); 340 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); 341 342 // Does one of my inputs spin in a tighter loop than self? 343 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || 344 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || 345 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) 346 return NULL; // Leave well enough alone 347 348 // Is at least one of my inputs loop-invariant? 349 if( n1_loop == n_loop && 350 n2_loop == n_loop && 351 n3_loop == n_loop ) 352 return NULL; // No loop-invariant inputs 353 354 355 int n_op = n->Opcode(); 356 357 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). 358 if( n_op == Op_LShiftI ) { 359 // Scale is loop invariant 360 Node *scale = n->in(2); 361 Node *scale_ctrl = get_ctrl(scale); 362 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); 363 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) 364 return NULL; 365 const TypeInt *scale_t = scale->bottom_type()->isa_int(); 366 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) 367 return NULL; // Dont bother with byte/short masking 368 // Add must vary with loop (else shift would be loop-invariant) 369 Node *add = n->in(1); 370 Node *add_ctrl = get_ctrl(add); 371 IdealLoopTree *add_loop = get_loop(add_ctrl); 372 //assert( n_loop == add_loop, "" ); 373 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops 374 375 // Convert I-V into I+ (0-V); same for V-I 376 if( add->Opcode() == Op_SubI && 377 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { 378 Node *zero = _igvn.intcon(0); 379 set_ctrl(zero, C->root()); 380 Node *neg = new SubINode( _igvn.intcon(0), add->in(2) ); 381 register_new_node( neg, get_ctrl(add->in(2) ) ); 382 add = new AddINode( add->in(1), neg ); 383 register_new_node( add, add_ctrl ); 384 } 385 if( add->Opcode() != Op_AddI ) return NULL; 386 // See if one add input is loop invariant 387 Node *add_var = add->in(1); 388 Node *add_var_ctrl = get_ctrl(add_var); 389 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); 390 Node *add_invar = add->in(2); 391 Node *add_invar_ctrl = get_ctrl(add_invar); 392 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); 393 if( add_var_loop == n_loop ) { 394 } else if( add_invar_loop == n_loop ) { 395 // Swap to find the invariant part 396 add_invar = add_var; 397 add_invar_ctrl = add_var_ctrl; 398 add_invar_loop = add_var_loop; 399 add_var = add->in(2); 400 Node *add_var_ctrl = get_ctrl(add_var); 401 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); 402 } else // Else neither input is loop invariant 403 return NULL; 404 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) 405 return NULL; // No invariant part of the add? 406 407 // Yes! Reshape address expression! 408 Node *inv_scale = new LShiftINode( add_invar, scale ); 409 Node *inv_scale_ctrl = 410 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? 411 add_invar_ctrl : scale_ctrl; 412 register_new_node( inv_scale, inv_scale_ctrl ); 413 Node *var_scale = new LShiftINode( add_var, scale ); 414 register_new_node( var_scale, n_ctrl ); 415 Node *var_add = new AddINode( var_scale, inv_scale ); 416 register_new_node( var_add, n_ctrl ); 417 _igvn.replace_node( n, var_add ); 418 return var_add; 419 } 420 421 // Replace (I+V) with (V+I) 422 if( n_op == Op_AddI || 423 n_op == Op_AddL || 424 n_op == Op_AddF || 425 n_op == Op_AddD || 426 n_op == Op_MulI || 427 n_op == Op_MulL || 428 n_op == Op_MulF || 429 n_op == Op_MulD ) { 430 if( n2_loop == n_loop ) { 431 assert( n1_loop != n_loop, "" ); 432 n->swap_edges(1, 2); 433 } 434 } 435 436 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), 437 // but not if I2 is a constant. 438 if( n_op == Op_AddP ) { 439 if( n2_loop == n_loop && n3_loop != n_loop ) { 440 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { 441 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); 442 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); 443 IdealLoopTree *n22loop = get_loop( n22_ctrl ); 444 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); 445 if( n22loop != n_loop && n22loop->is_member(n_loop) && 446 n23_loop == n_loop ) { 447 Node *add1 = new AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); 448 // Stuff new AddP in the loop preheader 449 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); 450 Node *add2 = new AddPNode( n->in(1), add1, n->in(2)->in(3) ); 451 register_new_node( add2, n_ctrl ); 452 _igvn.replace_node( n, add2 ); 453 return add2; 454 } 455 } 456 } 457 458 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) 459 if (n2_loop != n_loop && n3_loop == n_loop) { 460 if (n->in(3)->Opcode() == Op_AddX) { 461 Node *V = n->in(3)->in(1); 462 Node *I = n->in(3)->in(2); 463 if (is_member(n_loop,get_ctrl(V))) { 464 } else { 465 Node *tmp = V; V = I; I = tmp; 466 } 467 if (!is_member(n_loop,get_ctrl(I))) { 468 Node *add1 = new AddPNode(n->in(1), n->in(2), I); 469 // Stuff new AddP in the loop preheader 470 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl)); 471 Node *add2 = new AddPNode(n->in(1), add1, V); 472 register_new_node(add2, n_ctrl); 473 _igvn.replace_node(n, add2); 474 return add2; 475 } 476 } 477 } 478 } 479 480 return NULL; 481 } 482 483 //------------------------------conditional_move------------------------------- 484 // Attempt to replace a Phi with a conditional move. We have some pretty 485 // strict profitability requirements. All Phis at the merge point must 486 // be converted, so we can remove the control flow. We need to limit the 487 // number of c-moves to a small handful. All code that was in the side-arms 488 // of the CFG diamond is now speculatively executed. This code has to be 489 // "cheap enough". We are pretty much limited to CFG diamonds that merge 490 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. 491 Node *PhaseIdealLoop::conditional_move( Node *region ) { 492 493 assert(region->is_Region(), "sanity check"); 494 if (region->req() != 3) return NULL; 495 496 // Check for CFG diamond 497 Node *lp = region->in(1); 498 Node *rp = region->in(2); 499 if (!lp || !rp) return NULL; 500 Node *lp_c = lp->in(0); 501 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL; 502 IfNode *iff = lp_c->as_If(); 503 504 // Check for ops pinned in an arm of the diamond. 505 // Can't remove the control flow in this case 506 if (lp->outcnt() > 1) return NULL; 507 if (rp->outcnt() > 1) return NULL; 508 509 IdealLoopTree* r_loop = get_loop(region); 510 assert(r_loop == get_loop(iff), "sanity"); 511 // Always convert to CMOVE if all results are used only outside this loop. 512 bool used_inside_loop = (r_loop == _ltree_root); 513 514 // Check profitability 515 int cost = 0; 516 int phis = 0; 517 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 518 Node *out = region->fast_out(i); 519 if (!out->is_Phi()) continue; // Ignore other control edges, etc 520 phis++; 521 PhiNode* phi = out->as_Phi(); 522 BasicType bt = phi->type()->basic_type(); 523 switch (bt) { 524 case T_DOUBLE: 525 if (C->use_cmove()) { 526 continue; //TODO: maybe we want to add some cost 527 } 528 case T_FLOAT: { 529 cost += Matcher::float_cmove_cost(); // Could be very expensive 530 break; 531 } 532 case T_LONG: { 533 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's 534 } 535 case T_INT: // These all CMOV fine 536 case T_ADDRESS: { // (RawPtr) 537 cost++; 538 break; 539 } 540 case T_NARROWOOP: // Fall through 541 case T_OBJECT: { // Base oops are OK, but not derived oops 542 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); 543 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a 544 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus 545 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we 546 // have a Phi for the base here that we convert to a CMOVE all is well 547 // and good. But if the base is dead, we'll not make a CMOVE. Later 548 // the allocator will have to produce a base by creating a CMOVE of the 549 // relevant bases. This puts the allocator in the business of 550 // manufacturing expensive instructions, generally a bad plan. 551 // Just Say No to Conditionally-Moved Derived Pointers. 552 if (tp && tp->offset() != 0) 553 return NULL; 554 cost++; 555 break; 556 } 557 default: 558 return NULL; // In particular, can't do memory or I/O 559 } 560 // Add in cost any speculative ops 561 for (uint j = 1; j < region->req(); j++) { 562 Node *proj = region->in(j); 563 Node *inp = phi->in(j); 564 if (get_ctrl(inp) == proj) { // Found local op 565 cost++; 566 // Check for a chain of dependent ops; these will all become 567 // speculative in a CMOV. 568 for (uint k = 1; k < inp->req(); k++) 569 if (get_ctrl(inp->in(k)) == proj) 570 cost += ConditionalMoveLimit; // Too much speculative goo 571 } 572 } 573 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. 574 // This will likely Split-If, a higher-payoff operation. 575 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { 576 Node* use = phi->fast_out(k); 577 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr()) 578 cost += ConditionalMoveLimit; 579 // Is there a use inside the loop? 580 // Note: check only basic types since CMoveP is pinned. 581 if (!used_inside_loop && is_java_primitive(bt)) { 582 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use); 583 if (r_loop == u_loop || r_loop->is_member(u_loop)) { 584 used_inside_loop = true; 585 } 586 } 587 } 588 }//for 589 Node* bol = iff->in(1); 590 assert(bol->Opcode() == Op_Bool, ""); 591 int cmp_op = bol->in(1)->Opcode(); 592 // It is expensive to generate flags from a float compare. 593 // Avoid duplicated float compare. 594 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; 595 596 float infrequent_prob = PROB_UNLIKELY_MAG(3); 597 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop. 598 if (used_inside_loop) { 599 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo 600 601 // BlockLayoutByFrequency optimization moves infrequent branch 602 // from hot path. No point in CMOV'ing in such case (110 is used 603 // instead of 100 to take into account not exactness of float value). 604 if (BlockLayoutByFrequency) { 605 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f); 606 } 607 } 608 // Check for highly predictable branch. No point in CMOV'ing if 609 // we are going to predict accurately all the time. 610 if (C->use_cmove() && cmp_op == Op_CmpD) ;//keep going 611 else if (iff->_prob < infrequent_prob || 612 iff->_prob > (1.0f - infrequent_prob)) 613 return NULL; 614 615 // -------------- 616 // Now replace all Phis with CMOV's 617 Node *cmov_ctrl = iff->in(0); 618 uint flip = (lp->Opcode() == Op_IfTrue); 619 Node_List wq; 620 while (1) { 621 PhiNode* phi = NULL; 622 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 623 Node *out = region->fast_out(i); 624 if (out->is_Phi()) { 625 phi = out->as_Phi(); 626 break; 627 } 628 } 629 if (phi == NULL) break; 630 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); } 631 // Move speculative ops 632 wq.push(phi); 633 while (wq.size() > 0) { 634 Node *n = wq.pop(); 635 for (uint j = 1; j < n->req(); j++) { 636 Node* m = n->in(j); 637 if (m != NULL && !is_dominator(get_ctrl(m), cmov_ctrl)) { 638 #ifndef PRODUCT 639 if (PrintOpto && VerifyLoopOptimizations) { 640 tty->print(" speculate: "); 641 m->dump(); 642 } 643 #endif 644 set_ctrl(m, cmov_ctrl); 645 wq.push(m); 646 } 647 } 648 } 649 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi)); 650 register_new_node( cmov, cmov_ctrl ); 651 _igvn.replace_node( phi, cmov ); 652 #ifndef PRODUCT 653 if (TraceLoopOpts) { 654 tty->print("CMOV "); 655 r_loop->dump_head(); 656 if (Verbose) { 657 bol->in(1)->dump(1); 658 cmov->dump(1); 659 } 660 } 661 if (VerifyLoopOptimizations) verify(); 662 #endif 663 } 664 665 // The useless CFG diamond will fold up later; see the optimization in 666 // RegionNode::Ideal. 667 _igvn._worklist.push(region); 668 669 return iff->in(1); 670 } 671 672 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) { 673 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) { 674 Node* u = m->fast_out(i); 675 if (u->is_CFG()) { 676 if (u->Opcode() == Op_NeverBranch) { 677 u = ((NeverBranchNode*)u)->proj_out(0); 678 enqueue_cfg_uses(u, wq); 679 } else { 680 wq.push(u); 681 } 682 } 683 } 684 } 685 686 // Try moving a store out of a loop, right before the loop 687 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) { 688 // Store has to be first in the loop body 689 IdealLoopTree *n_loop = get_loop(n_ctrl); 690 if (n->is_Store() && n_loop != _ltree_root && n_loop->is_loop() && n->in(0) != NULL) { 691 Node* address = n->in(MemNode::Address); 692 Node* value = n->in(MemNode::ValueIn); 693 Node* mem = n->in(MemNode::Memory); 694 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 695 IdealLoopTree* value_loop = get_loop(get_ctrl(value)); 696 697 // - address and value must be loop invariant 698 // - memory must be a memory Phi for the loop 699 // - Store must be the only store on this memory slice in the 700 // loop: if there's another store following this one then value 701 // written at iteration i by the second store could be overwritten 702 // at iteration i+n by the first store: it's not safe to move the 703 // first store out of the loop 704 // - nothing must observe the memory Phi: it guarantees no read 705 // before the store, we are also guaranteed the store post 706 // dominates the loop head (ignoring a possible early 707 // exit). Otherwise there would be extra Phi involved between the 708 // loop's Phi and the store. 709 // - there must be no early exit from the loop before the Store 710 // (such an exit most of the time would be an extra use of the 711 // memory Phi but sometimes is a bottom memory Phi that takes the 712 // store as input). 713 714 if (!n_loop->is_member(address_loop) && 715 !n_loop->is_member(value_loop) && 716 mem->is_Phi() && mem->in(0) == n_loop->_head && 717 mem->outcnt() == 1 && 718 mem->in(LoopNode::LoopBackControl) == n) { 719 720 assert(n_loop->_tail != NULL, "need a tail"); 721 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop"); 722 723 // Verify that there's no early exit of the loop before the store. 724 bool ctrl_ok = false; 725 { 726 // Follow control from loop head until n, we exit the loop or 727 // we reach the tail 728 ResourceMark rm; 729 Unique_Node_List wq; 730 wq.push(n_loop->_head); 731 732 for (uint next = 0; next < wq.size(); ++next) { 733 Node *m = wq.at(next); 734 if (m == n->in(0)) { 735 ctrl_ok = true; 736 continue; 737 } 738 assert(!has_ctrl(m), "should be CFG"); 739 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) { 740 ctrl_ok = false; 741 break; 742 } 743 enqueue_cfg_uses(m, wq); 744 if (wq.size() > 10) { 745 ctrl_ok = false; 746 break; 747 } 748 } 749 } 750 if (ctrl_ok) { 751 // move the Store 752 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem); 753 _igvn.replace_input_of(n, 0, n_loop->_head->in(LoopNode::EntryControl)); 754 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl)); 755 // Disconnect the phi now. An empty phi can confuse other 756 // optimizations in this pass of loop opts. 757 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl)); 758 n_loop->_body.yank(mem); 759 760 IdealLoopTree* new_loop = get_loop(n->in(0)); 761 set_ctrl_and_loop(n, n->in(0)); 762 763 return n; 764 } 765 } 766 } 767 return NULL; 768 } 769 770 // Try moving a store out of a loop, right after the loop 771 void PhaseIdealLoop::try_move_store_after_loop(Node* n) { 772 if (n->is_Store() && n->in(0) != NULL) { 773 Node *n_ctrl = get_ctrl(n); 774 IdealLoopTree *n_loop = get_loop(n_ctrl); 775 // Store must be in a loop 776 if (n_loop != _ltree_root && !n_loop->_irreducible) { 777 Node* address = n->in(MemNode::Address); 778 Node* value = n->in(MemNode::ValueIn); 779 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 780 // address must be loop invariant 781 if (!n_loop->is_member(address_loop)) { 782 // Store must be last on this memory slice in the loop and 783 // nothing in the loop must observe it 784 Node* phi = NULL; 785 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 786 Node* u = n->fast_out(i); 787 if (has_ctrl(u)) { // control use? 788 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); 789 if (!n_loop->is_member(u_loop)) { 790 continue; 791 } 792 if (u->is_Phi() && u->in(0) == n_loop->_head) { 793 assert(_igvn.type(u) == Type::MEMORY, "bad phi"); 794 // multiple phis on the same slice are possible 795 if (phi != NULL) { 796 return; 797 } 798 phi = u; 799 continue; 800 } 801 } 802 return; 803 } 804 if (phi != NULL) { 805 // Nothing in the loop before the store (next iteration) 806 // must observe the stored value 807 bool mem_ok = true; 808 { 809 ResourceMark rm; 810 Unique_Node_List wq; 811 wq.push(phi); 812 for (uint next = 0; next < wq.size() && mem_ok; ++next) { 813 Node *m = wq.at(next); 814 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) { 815 Node* u = m->fast_out(i); 816 if (u->is_Store() || u->is_Phi()) { 817 if (u != n) { 818 wq.push(u); 819 mem_ok = (wq.size() <= 10); 820 } 821 } else { 822 mem_ok = false; 823 break; 824 } 825 } 826 } 827 } 828 if (mem_ok) { 829 // Move the store out of the loop if the LCA of all 830 // users (except for the phi) is outside the loop. 831 Node* hook = new Node(1); 832 _igvn.rehash_node_delayed(phi); 833 int count = phi->replace_edge(n, hook); 834 assert(count > 0, "inconsistent phi"); 835 836 // Compute latest point this store can go 837 Node* lca = get_late_ctrl(n, get_ctrl(n)); 838 if (n_loop->is_member(get_loop(lca))) { 839 // LCA is in the loop - bail out 840 _igvn.replace_node(hook, n); 841 return; 842 } 843 844 // Move store out of the loop 845 _igvn.replace_node(hook, n->in(MemNode::Memory)); 846 _igvn.replace_input_of(n, 0, lca); 847 set_ctrl_and_loop(n, lca); 848 849 // Disconnect the phi now. An empty phi can confuse other 850 // optimizations in this pass of loop opts.. 851 if (phi->in(LoopNode::LoopBackControl) == phi) { 852 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl)); 853 n_loop->_body.yank(phi); 854 } 855 } 856 } 857 } 858 } 859 } 860 } 861 862 //------------------------------split_if_with_blocks_pre----------------------- 863 // Do the real work in a non-recursive function. Data nodes want to be 864 // cloned in the pre-order so they can feed each other nicely. 865 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { 866 // Cloning these guys is unlikely to win 867 int n_op = n->Opcode(); 868 if( n_op == Op_MergeMem ) return n; 869 if( n->is_Proj() ) return n; 870 // Do not clone-up CmpFXXX variations, as these are always 871 // followed by a CmpI 872 if( n->is_Cmp() ) return n; 873 // Attempt to use a conditional move instead of a phi/branch 874 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { 875 Node *cmov = conditional_move( n ); 876 if( cmov ) return cmov; 877 } 878 if( n->is_CFG() || n->is_LoadStore() ) 879 return n; 880 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd 881 n_op == Op_Opaque2 ) { 882 if( !C->major_progress() ) // If chance of no more loop opts... 883 _igvn._worklist.push(n); // maybe we'll remove them 884 return n; 885 } 886 887 if( n->is_Con() ) return n; // No cloning for Con nodes 888 889 Node *n_ctrl = get_ctrl(n); 890 if( !n_ctrl ) return n; // Dead node 891 892 Node* res = try_move_store_before_loop(n, n_ctrl); 893 if (res != NULL) { 894 return n; 895 } 896 897 // Attempt to remix address expressions for loop invariants 898 Node *m = remix_address_expressions( n ); 899 if( m ) return m; 900 901 if (n->is_ConstraintCast()) { 902 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this); 903 // ConstraintCastNode::dominating_cast() uses node control input to determine domination. 904 // Node control inputs don't necessarily agree with loop control info (due to 905 // transformations happened in between), thus additional dominance check is needed 906 // to keep loop info valid. 907 if (dom_cast != NULL && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) { 908 _igvn.replace_node(n, dom_cast); 909 return dom_cast; 910 } 911 } 912 913 // Determine if the Node has inputs from some local Phi. 914 // Returns the block to clone thru. 915 Node *n_blk = has_local_phi_input( n ); 916 if( !n_blk ) return n; 917 918 // Do not clone the trip counter through on a CountedLoop 919 // (messes up the canonical shape). 920 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; 921 922 // Check for having no control input; not pinned. Allow 923 // dominating control. 924 if (n->in(0)) { 925 Node *dom = idom(n_blk); 926 if (dom_lca(n->in(0), dom) != n->in(0)) { 927 return n; 928 } 929 } 930 // Policy: when is it profitable. You must get more wins than 931 // policy before it is considered profitable. Policy is usually 0, 932 // so 1 win is considered profitable. Big merges will require big 933 // cloning, so get a larger policy. 934 int policy = n_blk->req() >> 2; 935 936 // If the loop is a candidate for range check elimination, 937 // delay splitting through it's phi until a later loop optimization 938 if (n_blk->is_CountedLoop()) { 939 IdealLoopTree *lp = get_loop(n_blk); 940 if (lp && lp->_rce_candidate) { 941 return n; 942 } 943 } 944 945 // Use same limit as split_if_with_blocks_post 946 if( C->live_nodes() > 35000 ) return n; // Method too big 947 948 // Split 'n' through the merge point if it is profitable 949 Node *phi = split_thru_phi( n, n_blk, policy ); 950 if (!phi) return n; 951 952 // Found a Phi to split thru! 953 // Replace 'n' with the new phi 954 _igvn.replace_node( n, phi ); 955 // Moved a load around the loop, 'en-registering' something. 956 if (n_blk->is_Loop() && n->is_Load() && 957 !phi->in(LoopNode::LoopBackControl)->is_Load()) 958 C->set_major_progress(); 959 960 return phi; 961 } 962 963 static bool merge_point_too_heavy(Compile* C, Node* region) { 964 // Bail out if the region and its phis have too many users. 965 int weight = 0; 966 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 967 weight += region->fast_out(i)->outcnt(); 968 } 969 int nodes_left = C->max_node_limit() - C->live_nodes(); 970 if (weight * 8 > nodes_left) { 971 if (PrintOpto) { 972 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); 973 } 974 return true; 975 } else { 976 return false; 977 } 978 } 979 980 static bool merge_point_safe(Node* region) { 981 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode 982 // having a PhiNode input. This sidesteps the dangerous case where the split 983 // ConvI2LNode may become TOP if the input Value() does not 984 // overlap the ConvI2L range, leaving a node which may not dominate its 985 // uses. 986 // A better fix for this problem can be found in the BugTraq entry, but 987 // expediency for Mantis demands this hack. 988 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop 989 // split_if_with_blocks from splitting a block because we could not move around 990 // the FastLockNode. 991 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 992 Node* n = region->fast_out(i); 993 if (n->is_Phi()) { 994 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 995 Node* m = n->fast_out(j); 996 if (m->is_FastLock()) 997 return false; 998 #ifdef _LP64 999 if (m->Opcode() == Op_ConvI2L) 1000 return false; 1001 if (m->is_CastII() && m->isa_CastII()->has_range_check()) { 1002 return false; 1003 } 1004 #endif 1005 } 1006 } 1007 } 1008 return true; 1009 } 1010 1011 1012 //------------------------------place_near_use--------------------------------- 1013 // Place some computation next to use but not inside inner loops. 1014 // For inner loop uses move it to the preheader area. 1015 Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { 1016 IdealLoopTree *u_loop = get_loop( useblock ); 1017 return (u_loop->_irreducible || u_loop->_child) 1018 ? useblock 1019 : u_loop->_head->in(LoopNode::EntryControl); 1020 } 1021 1022 1023 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) { 1024 if (!n->is_If()) { 1025 return false; 1026 } 1027 if (!n->in(0)->is_Region()) { 1028 return false; 1029 } 1030 Node* region = n->in(0); 1031 Node* dom = idom(region); 1032 if (!dom->is_If() || dom->in(1) != n->in(1)) { 1033 return false; 1034 } 1035 IfNode* dom_if = dom->as_If(); 1036 Node* proj_true = dom_if->proj_out(1); 1037 Node* proj_false = dom_if->proj_out(0); 1038 1039 for (uint i = 1; i < region->req(); i++) { 1040 if (is_dominator(proj_true, region->in(i))) { 1041 continue; 1042 } 1043 if (is_dominator(proj_false, region->in(i))) { 1044 continue; 1045 } 1046 return false; 1047 } 1048 1049 return true; 1050 } 1051 1052 bool PhaseIdealLoop::can_split_if(Node *n_ctrl) { 1053 if (C->live_nodes() > 35000) { 1054 return false; // Method too big 1055 } 1056 1057 // Do not do 'split-if' if irreducible loops are present. 1058 if (_has_irreducible_loops) { 1059 return false; 1060 } 1061 1062 if (merge_point_too_heavy(C, n_ctrl)) { 1063 return false; 1064 } 1065 1066 // Do not do 'split-if' if some paths are dead. First do dead code 1067 // elimination and then see if its still profitable. 1068 for (uint i = 1; i < n_ctrl->req(); i++) { 1069 if (n_ctrl->in(i) == C->top()) { 1070 return false; 1071 } 1072 } 1073 1074 // If trying to do a 'Split-If' at the loop head, it is only 1075 // profitable if the cmp folds up on BOTH paths. Otherwise we 1076 // risk peeling a loop forever. 1077 1078 // CNC - Disabled for now. Requires careful handling of loop 1079 // body selection for the cloned code. Also, make sure we check 1080 // for any input path not being in the same loop as n_ctrl. For 1081 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' 1082 // because the alternative loop entry points won't be converted 1083 // into LoopNodes. 1084 IdealLoopTree *n_loop = get_loop(n_ctrl); 1085 for (uint j = 1; j < n_ctrl->req(); j++) { 1086 if (get_loop(n_ctrl->in(j)) != n_loop) { 1087 return false; 1088 } 1089 } 1090 1091 // Check for safety of the merge point. 1092 if (!merge_point_safe(n_ctrl)) { 1093 return false; 1094 } 1095 1096 return true; 1097 } 1098 1099 //------------------------------split_if_with_blocks_post---------------------- 1100 // Do the real work in a non-recursive function. CFG hackery wants to be 1101 // in the post-order, so it can dirty the I-DOM info and not use the dirtied 1102 // info. 1103 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) { 1104 1105 // Cloning Cmp through Phi's involves the split-if transform. 1106 // FastLock is not used by an If 1107 if (n->is_Cmp() && !n->is_FastLock()) { 1108 Node *n_ctrl = get_ctrl(n); 1109 // Determine if the Node has inputs from some local Phi. 1110 // Returns the block to clone thru. 1111 Node *n_blk = has_local_phi_input(n); 1112 if (n_blk != n_ctrl) { 1113 return; 1114 } 1115 1116 if (!can_split_if(n_ctrl)) { 1117 return; 1118 } 1119 1120 if (n->outcnt() != 1) { 1121 return; // Multiple bool's from 1 compare? 1122 } 1123 Node *bol = n->unique_out(); 1124 assert(bol->is_Bool(), "expect a bool here"); 1125 if (bol->outcnt() != 1) { 1126 return;// Multiple branches from 1 compare? 1127 } 1128 Node *iff = bol->unique_out(); 1129 1130 // Check some safety conditions 1131 if (iff->is_If()) { // Classic split-if? 1132 if (iff->in(0) != n_ctrl) { 1133 return; // Compare must be in same blk as if 1134 } 1135 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE 1136 // Can't split CMove with different control edge. 1137 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) { 1138 return; 1139 } 1140 if (get_ctrl(iff->in(2)) == n_ctrl || 1141 get_ctrl(iff->in(3)) == n_ctrl) { 1142 return; // Inputs not yet split-up 1143 } 1144 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) { 1145 return; // Loop-invar test gates loop-varying CMOVE 1146 } 1147 } else { 1148 return; // some other kind of node, such as an Allocate 1149 } 1150 1151 // When is split-if profitable? Every 'win' on means some control flow 1152 // goes dead, so it's almost always a win. 1153 int policy = 0; 1154 // Split compare 'n' through the merge point if it is profitable 1155 Node *phi = split_thru_phi( n, n_ctrl, policy); 1156 if (!phi) { 1157 return; 1158 } 1159 1160 // Found a Phi to split thru! 1161 // Replace 'n' with the new phi 1162 _igvn.replace_node(n, phi); 1163 1164 // Now split the bool up thru the phi 1165 Node *bolphi = split_thru_phi(bol, n_ctrl, -1); 1166 guarantee(bolphi != NULL, "null boolean phi node"); 1167 1168 _igvn.replace_node(bol, bolphi); 1169 assert(iff->in(1) == bolphi, ""); 1170 1171 if (bolphi->Value(&_igvn)->singleton()) { 1172 return; 1173 } 1174 1175 // Conditional-move? Must split up now 1176 if (!iff->is_If()) { 1177 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1); 1178 _igvn.replace_node(iff, cmovphi); 1179 return; 1180 } 1181 1182 // Now split the IF 1183 do_split_if(iff); 1184 return; 1185 } 1186 1187 // Two identical ifs back to back can be merged 1188 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) { 1189 Node *n_ctrl = n->in(0); 1190 PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1)); 1191 IfNode* dom_if = idom(n_ctrl)->as_If(); 1192 Node* proj_true = dom_if->proj_out(1); 1193 Node* proj_false = dom_if->proj_out(0); 1194 Node* con_true = _igvn.makecon(TypeInt::ONE); 1195 Node* con_false = _igvn.makecon(TypeInt::ZERO); 1196 1197 for (uint i = 1; i < n_ctrl->req(); i++) { 1198 if (is_dominator(proj_true, n_ctrl->in(i))) { 1199 bolphi->init_req(i, con_true); 1200 } else { 1201 assert(is_dominator(proj_false, n_ctrl->in(i)), "bad if"); 1202 bolphi->init_req(i, con_false); 1203 } 1204 } 1205 register_new_node(bolphi, n_ctrl); 1206 _igvn.replace_input_of(n, 1, bolphi); 1207 1208 // Now split the IF 1209 do_split_if(n); 1210 return; 1211 } 1212 1213 // Check for an IF ready to split; one that has its 1214 // condition codes input coming from a Phi at the block start. 1215 int n_op = n->Opcode(); 1216 1217 // Check for an IF being dominated by another IF same test 1218 if (n_op == Op_If || 1219 n_op == Op_RangeCheck) { 1220 Node *bol = n->in(1); 1221 uint max = bol->outcnt(); 1222 // Check for same test used more than once? 1223 if (max > 1 && bol->is_Bool()) { 1224 // Search up IDOMs to see if this IF is dominated. 1225 Node *cutoff = get_ctrl(bol); 1226 1227 // Now search up IDOMs till cutoff, looking for a dominating test 1228 Node *prevdom = n; 1229 Node *dom = idom(prevdom); 1230 while (dom != cutoff) { 1231 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) { 1232 // Replace the dominated test with an obvious true or false. 1233 // Place it on the IGVN worklist for later cleanup. 1234 C->set_major_progress(); 1235 dominated_by(prevdom, n, false, true); 1236 #ifndef PRODUCT 1237 if( VerifyLoopOptimizations ) verify(); 1238 #endif 1239 return; 1240 } 1241 prevdom = dom; 1242 dom = idom(prevdom); 1243 } 1244 } 1245 } 1246 1247 // See if a shared loop-varying computation has no loop-varying uses. 1248 // Happens if something is only used for JVM state in uncommon trap exits, 1249 // like various versions of induction variable+offset. Clone the 1250 // computation per usage to allow it to sink out of the loop. 1251 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) 1252 Node *n_ctrl = get_ctrl(n); 1253 IdealLoopTree *n_loop = get_loop(n_ctrl); 1254 if( n_loop != _ltree_root ) { 1255 DUIterator_Fast imax, i = n->fast_outs(imax); 1256 for (; i < imax; i++) { 1257 Node* u = n->fast_out(i); 1258 if( !has_ctrl(u) ) break; // Found control user 1259 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); 1260 if( u_loop == n_loop ) break; // Found loop-varying use 1261 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop 1262 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 1263 } 1264 bool did_break = (i < imax); // Did we break out of the previous loop? 1265 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! 1266 Node *late_load_ctrl = NULL; 1267 if (n->is_Load()) { 1268 // If n is a load, get and save the result from get_late_ctrl(), 1269 // to be later used in calculating the control for n's clones. 1270 clear_dom_lca_tags(); 1271 late_load_ctrl = get_late_ctrl(n, n_ctrl); 1272 } 1273 // If n is a load, and the late control is the same as the current 1274 // control, then the cloning of n is a pointless exercise, because 1275 // GVN will ensure that we end up where we started. 1276 if (!n->is_Load() || late_load_ctrl != n_ctrl) { 1277 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { 1278 Node *u = n->last_out(j); // Clone private computation per use 1279 _igvn.rehash_node_delayed(u); 1280 Node *x = n->clone(); // Clone computation 1281 Node *x_ctrl = NULL; 1282 if( u->is_Phi() ) { 1283 // Replace all uses of normal nodes. Replace Phi uses 1284 // individually, so the separate Nodes can sink down 1285 // different paths. 1286 uint k = 1; 1287 while( u->in(k) != n ) k++; 1288 u->set_req( k, x ); 1289 // x goes next to Phi input path 1290 x_ctrl = u->in(0)->in(k); 1291 --j; 1292 } else { // Normal use 1293 // Replace all uses 1294 for( uint k = 0; k < u->req(); k++ ) { 1295 if( u->in(k) == n ) { 1296 u->set_req( k, x ); 1297 --j; 1298 } 1299 } 1300 x_ctrl = get_ctrl(u); 1301 } 1302 1303 // Find control for 'x' next to use but not inside inner loops. 1304 // For inner loop uses get the preheader area. 1305 x_ctrl = place_near_use(x_ctrl); 1306 1307 if (n->is_Load()) { 1308 // For loads, add a control edge to a CFG node outside of the loop 1309 // to force them to not combine and return back inside the loop 1310 // during GVN optimization (4641526). 1311 // 1312 // Because we are setting the actual control input, factor in 1313 // the result from get_late_ctrl() so we respect any 1314 // anti-dependences. (6233005). 1315 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); 1316 1317 // Don't allow the control input to be a CFG splitting node. 1318 // Such nodes should only have ProjNodes as outs, e.g. IfNode 1319 // should only have IfTrueNode and IfFalseNode (4985384). 1320 x_ctrl = find_non_split_ctrl(x_ctrl); 1321 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); 1322 1323 x->set_req(0, x_ctrl); 1324 } 1325 register_new_node(x, x_ctrl); 1326 1327 // Some institutional knowledge is needed here: 'x' is 1328 // yanked because if the optimizer runs GVN on it all the 1329 // cloned x's will common up and undo this optimization and 1330 // be forced back in the loop. This is annoying because it 1331 // makes +VerifyOpto report false-positives on progress. I 1332 // tried setting control edges on the x's to force them to 1333 // not combine, but the matching gets worried when it tries 1334 // to fold a StoreP and an AddP together (as part of an 1335 // address expression) and the AddP and StoreP have 1336 // different controls. 1337 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x); 1338 } 1339 _igvn.remove_dead_node(n); 1340 } 1341 } 1342 } 1343 } 1344 1345 try_move_store_after_loop(n); 1346 1347 // Check for Opaque2's who's loop has disappeared - who's input is in the 1348 // same loop nest as their output. Remove 'em, they are no longer useful. 1349 if( n_op == Op_Opaque2 && 1350 n->in(1) != NULL && 1351 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { 1352 _igvn.replace_node( n, n->in(1) ); 1353 } 1354 } 1355 1356 //------------------------------split_if_with_blocks--------------------------- 1357 // Check for aggressive application of 'split-if' optimization, 1358 // using basic block level info. 1359 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { 1360 Node *n = C->root(); 1361 visited.set(n->_idx); // first, mark node as visited 1362 // Do pre-visit work for root 1363 n = split_if_with_blocks_pre( n ); 1364 uint cnt = n->outcnt(); 1365 uint i = 0; 1366 while (true) { 1367 // Visit all children 1368 if (i < cnt) { 1369 Node* use = n->raw_out(i); 1370 ++i; 1371 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { 1372 // Now do pre-visit work for this use 1373 use = split_if_with_blocks_pre( use ); 1374 nstack.push(n, i); // Save parent and next use's index. 1375 n = use; // Process all children of current use. 1376 cnt = use->outcnt(); 1377 i = 0; 1378 } 1379 } 1380 else { 1381 // All of n's children have been processed, complete post-processing. 1382 if (cnt != 0 && !n->is_Con()) { 1383 assert(has_node(n), "no dead nodes"); 1384 split_if_with_blocks_post( n ); 1385 } 1386 if (nstack.is_empty()) { 1387 // Finished all nodes on stack. 1388 break; 1389 } 1390 // Get saved parent node and next use's index. Visit the rest of uses. 1391 n = nstack.node(); 1392 cnt = n->outcnt(); 1393 i = nstack.index(); 1394 nstack.pop(); 1395 } 1396 } 1397 } 1398 1399 1400 //============================================================================= 1401 // 1402 // C L O N E A L O O P B O D Y 1403 // 1404 1405 //------------------------------clone_iff-------------------------------------- 1406 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 1407 // "Nearly" because all Nodes have been cloned from the original in the loop, 1408 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 1409 // through the Phi recursively, and return a Bool. 1410 Node* PhaseIdealLoop::clone_iff(PhiNode *phi, IdealLoopTree *loop) { 1411 1412 // Convert this Phi into a Phi merging Bools 1413 uint i; 1414 for (i = 1; i < phi->req(); i++) { 1415 Node *b = phi->in(i); 1416 if (b->is_Phi()) { 1417 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi(), loop)); 1418 } else { 1419 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, ""); 1420 } 1421 } 1422 1423 Node* n = phi->in(1); 1424 Node* sample_opaque = NULL; 1425 Node *sample_bool = NULL; 1426 if (n->Opcode() == Op_Opaque4) { 1427 sample_opaque = n; 1428 sample_bool = n->in(1); 1429 assert(sample_bool->is_Bool(), "wrong type"); 1430 } else { 1431 sample_bool = n; 1432 } 1433 Node *sample_cmp = sample_bool->in(1); 1434 1435 // Make Phis to merge the Cmp's inputs. 1436 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP); 1437 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP); 1438 for (i = 1; i < phi->req(); i++) { 1439 Node *n1 = sample_opaque == NULL ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1); 1440 Node *n2 = sample_opaque == NULL ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2); 1441 phi1->set_req(i, n1); 1442 phi2->set_req(i, n2); 1443 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); 1444 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); 1445 } 1446 // See if these Phis have been made before. 1447 // Register with optimizer 1448 Node *hit1 = _igvn.hash_find_insert(phi1); 1449 if (hit1) { // Hit, toss just made Phi 1450 _igvn.remove_dead_node(phi1); // Remove new phi 1451 assert(hit1->is_Phi(), "" ); 1452 phi1 = (PhiNode*)hit1; // Use existing phi 1453 } else { // Miss 1454 _igvn.register_new_node_with_optimizer(phi1); 1455 } 1456 Node *hit2 = _igvn.hash_find_insert(phi2); 1457 if (hit2) { // Hit, toss just made Phi 1458 _igvn.remove_dead_node(phi2); // Remove new phi 1459 assert(hit2->is_Phi(), "" ); 1460 phi2 = (PhiNode*)hit2; // Use existing phi 1461 } else { // Miss 1462 _igvn.register_new_node_with_optimizer(phi2); 1463 } 1464 // Register Phis with loop/block info 1465 set_ctrl(phi1, phi->in(0)); 1466 set_ctrl(phi2, phi->in(0)); 1467 // Make a new Cmp 1468 Node *cmp = sample_cmp->clone(); 1469 cmp->set_req(1, phi1); 1470 cmp->set_req(2, phi2); 1471 _igvn.register_new_node_with_optimizer(cmp); 1472 set_ctrl(cmp, phi->in(0)); 1473 1474 // Make a new Bool 1475 Node *b = sample_bool->clone(); 1476 b->set_req(1,cmp); 1477 _igvn.register_new_node_with_optimizer(b); 1478 set_ctrl(b, phi->in(0)); 1479 1480 if (sample_opaque != NULL) { 1481 Node* opaque = sample_opaque->clone(); 1482 opaque->set_req(1, b); 1483 _igvn.register_new_node_with_optimizer(opaque); 1484 set_ctrl(opaque, phi->in(0)); 1485 return opaque; 1486 } 1487 1488 assert(b->is_Bool(), ""); 1489 return b; 1490 } 1491 1492 //------------------------------clone_bool------------------------------------- 1493 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 1494 // "Nearly" because all Nodes have been cloned from the original in the loop, 1495 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 1496 // through the Phi recursively, and return a Bool. 1497 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { 1498 uint i; 1499 // Convert this Phi into a Phi merging Bools 1500 for( i = 1; i < phi->req(); i++ ) { 1501 Node *b = phi->in(i); 1502 if( b->is_Phi() ) { 1503 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop )); 1504 } else { 1505 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); 1506 } 1507 } 1508 1509 Node *sample_cmp = phi->in(1); 1510 1511 // Make Phis to merge the Cmp's inputs. 1512 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP ); 1513 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP ); 1514 for( uint j = 1; j < phi->req(); j++ ) { 1515 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP 1516 Node *n1, *n2; 1517 if( cmp_top->is_Cmp() ) { 1518 n1 = cmp_top->in(1); 1519 n2 = cmp_top->in(2); 1520 } else { 1521 n1 = n2 = cmp_top; 1522 } 1523 phi1->set_req( j, n1 ); 1524 phi2->set_req( j, n2 ); 1525 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); 1526 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); 1527 } 1528 1529 // See if these Phis have been made before. 1530 // Register with optimizer 1531 Node *hit1 = _igvn.hash_find_insert(phi1); 1532 if( hit1 ) { // Hit, toss just made Phi 1533 _igvn.remove_dead_node(phi1); // Remove new phi 1534 assert( hit1->is_Phi(), "" ); 1535 phi1 = (PhiNode*)hit1; // Use existing phi 1536 } else { // Miss 1537 _igvn.register_new_node_with_optimizer(phi1); 1538 } 1539 Node *hit2 = _igvn.hash_find_insert(phi2); 1540 if( hit2 ) { // Hit, toss just made Phi 1541 _igvn.remove_dead_node(phi2); // Remove new phi 1542 assert( hit2->is_Phi(), "" ); 1543 phi2 = (PhiNode*)hit2; // Use existing phi 1544 } else { // Miss 1545 _igvn.register_new_node_with_optimizer(phi2); 1546 } 1547 // Register Phis with loop/block info 1548 set_ctrl(phi1, phi->in(0)); 1549 set_ctrl(phi2, phi->in(0)); 1550 // Make a new Cmp 1551 Node *cmp = sample_cmp->clone(); 1552 cmp->set_req( 1, phi1 ); 1553 cmp->set_req( 2, phi2 ); 1554 _igvn.register_new_node_with_optimizer(cmp); 1555 set_ctrl(cmp, phi->in(0)); 1556 1557 assert( cmp->is_Cmp(), "" ); 1558 return (CmpNode*)cmp; 1559 } 1560 1561 //------------------------------sink_use--------------------------------------- 1562 // If 'use' was in the loop-exit block, it now needs to be sunk 1563 // below the post-loop merge point. 1564 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { 1565 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { 1566 set_ctrl(use, post_loop); 1567 for (DUIterator j = use->outs(); use->has_out(j); j++) 1568 sink_use(use->out(j), post_loop); 1569 } 1570 } 1571 1572 //------------------------------clone_loop------------------------------------- 1573 // 1574 // C L O N E A L O O P B O D Y 1575 // 1576 // This is the basic building block of the loop optimizations. It clones an 1577 // entire loop body. It makes an old_new loop body mapping; with this mapping 1578 // you can find the new-loop equivalent to an old-loop node. All new-loop 1579 // nodes are exactly equal to their old-loop counterparts, all edges are the 1580 // same. All exits from the old-loop now have a RegionNode that merges the 1581 // equivalent new-loop path. This is true even for the normal "loop-exit" 1582 // condition. All uses of loop-invariant old-loop values now come from (one 1583 // or more) Phis that merge their new-loop equivalents. 1584 // 1585 // This operation leaves the graph in an illegal state: there are two valid 1586 // control edges coming from the loop pre-header to both loop bodies. I'll 1587 // definitely have to hack the graph after running this transform. 1588 // 1589 // From this building block I will further edit edges to perform loop peeling 1590 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. 1591 // 1592 // Parameter side_by_size_idom: 1593 // When side_by_size_idom is NULL, the dominator tree is constructed for 1594 // the clone loop to dominate the original. Used in construction of 1595 // pre-main-post loop sequence. 1596 // When nonnull, the clone and original are side-by-side, both are 1597 // dominated by the side_by_side_idom node. Used in construction of 1598 // unswitched loops. 1599 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, 1600 Node* side_by_side_idom) { 1601 1602 if (C->do_vector_loop() && PrintOpto) { 1603 const char* mname = C->method()->name()->as_quoted_ascii(); 1604 if (mname != NULL) { 1605 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname); 1606 } 1607 } 1608 1609 CloneMap& cm = C->clone_map(); 1610 Dict* dict = cm.dict(); 1611 if (C->do_vector_loop()) { 1612 cm.set_clone_idx(cm.max_gen()+1); 1613 #ifndef PRODUCT 1614 if (PrintOpto) { 1615 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx()); 1616 loop->dump_head(); 1617 } 1618 #endif 1619 } 1620 1621 // Step 1: Clone the loop body. Make the old->new mapping. 1622 uint i; 1623 for( i = 0; i < loop->_body.size(); i++ ) { 1624 Node *old = loop->_body.at(i); 1625 Node *nnn = old->clone(); 1626 old_new.map( old->_idx, nnn ); 1627 if (C->do_vector_loop()) { 1628 cm.verify_insert_and_clone(old, nnn, cm.clone_idx()); 1629 } 1630 _igvn.register_new_node_with_optimizer(nnn); 1631 } 1632 1633 1634 // Step 2: Fix the edges in the new body. If the old input is outside the 1635 // loop use it. If the old input is INside the loop, use the corresponding 1636 // new node instead. 1637 for( i = 0; i < loop->_body.size(); i++ ) { 1638 Node *old = loop->_body.at(i); 1639 Node *nnn = old_new[old->_idx]; 1640 // Fix CFG/Loop controlling the new node 1641 if (has_ctrl(old)) { 1642 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); 1643 } else { 1644 set_loop(nnn, loop->_parent); 1645 if (old->outcnt() > 0) { 1646 set_idom( nnn, old_new[idom(old)->_idx], dd ); 1647 } 1648 } 1649 // Correct edges to the new node 1650 for( uint j = 0; j < nnn->req(); j++ ) { 1651 Node *n = nnn->in(j); 1652 if( n ) { 1653 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); 1654 if( loop->is_member( old_in_loop ) ) 1655 nnn->set_req(j, old_new[n->_idx]); 1656 } 1657 } 1658 _igvn.hash_find_insert(nnn); 1659 } 1660 Node *newhead = old_new[loop->_head->_idx]; 1661 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); 1662 1663 1664 // Step 3: Now fix control uses. Loop varying control uses have already 1665 // been fixed up (as part of all input edges in Step 2). Loop invariant 1666 // control uses must be either an IfFalse or an IfTrue. Make a merge 1667 // point to merge the old and new IfFalse/IfTrue nodes; make the use 1668 // refer to this. 1669 ResourceArea *area = Thread::current()->resource_area(); 1670 Node_List worklist(area); 1671 uint new_counter = C->unique(); 1672 for( i = 0; i < loop->_body.size(); i++ ) { 1673 Node* old = loop->_body.at(i); 1674 if( !old->is_CFG() ) continue; 1675 Node* nnn = old_new[old->_idx]; 1676 1677 // Copy uses to a worklist, so I can munge the def-use info 1678 // with impunity. 1679 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) 1680 worklist.push(old->fast_out(j)); 1681 1682 while( worklist.size() ) { // Visit all uses 1683 Node *use = worklist.pop(); 1684 if (!has_node(use)) continue; // Ignore dead nodes 1685 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); 1686 if( !loop->is_member( use_loop ) && use->is_CFG() ) { 1687 // Both OLD and USE are CFG nodes here. 1688 assert( use->is_Proj(), "" ); 1689 1690 // Clone the loop exit control projection 1691 Node *newuse = use->clone(); 1692 if (C->do_vector_loop()) { 1693 cm.verify_insert_and_clone(use, newuse, cm.clone_idx()); 1694 } 1695 newuse->set_req(0,nnn); 1696 _igvn.register_new_node_with_optimizer(newuse); 1697 set_loop(newuse, use_loop); 1698 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); 1699 1700 // We need a Region to merge the exit from the peeled body and the 1701 // exit from the old loop body. 1702 RegionNode *r = new RegionNode(3); 1703 // Map the old use to the new merge point 1704 old_new.map( use->_idx, r ); 1705 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); 1706 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); 1707 1708 // The original user of 'use' uses 'r' instead. 1709 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { 1710 Node* useuse = use->last_out(l); 1711 _igvn.rehash_node_delayed(useuse); 1712 uint uses_found = 0; 1713 if( useuse->in(0) == use ) { 1714 useuse->set_req(0, r); 1715 uses_found++; 1716 if( useuse->is_CFG() ) { 1717 assert( dom_depth(useuse) > dd_r, "" ); 1718 set_idom(useuse, r, dom_depth(useuse)); 1719 } 1720 } 1721 for( uint k = 1; k < useuse->req(); k++ ) { 1722 if( useuse->in(k) == use ) { 1723 useuse->set_req(k, r); 1724 uses_found++; 1725 } 1726 } 1727 l -= uses_found; // we deleted 1 or more copies of this edge 1728 } 1729 1730 // Now finish up 'r' 1731 r->set_req( 1, newuse ); 1732 r->set_req( 2, use ); 1733 _igvn.register_new_node_with_optimizer(r); 1734 set_loop(r, use_loop); 1735 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); 1736 } // End of if a loop-exit test 1737 } 1738 } 1739 1740 // Step 4: If loop-invariant use is not control, it must be dominated by a 1741 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region 1742 // there if needed. Make a Phi there merging old and new used values. 1743 Node_List *split_if_set = NULL; 1744 Node_List *split_bool_set = NULL; 1745 Node_List *split_cex_set = NULL; 1746 for( i = 0; i < loop->_body.size(); i++ ) { 1747 Node* old = loop->_body.at(i); 1748 Node* nnn = old_new[old->_idx]; 1749 // Copy uses to a worklist, so I can munge the def-use info 1750 // with impunity. 1751 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) 1752 worklist.push(old->fast_out(j)); 1753 1754 while( worklist.size() ) { 1755 Node *use = worklist.pop(); 1756 if (!has_node(use)) continue; // Ignore dead nodes 1757 if (use->in(0) == C->top()) continue; 1758 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); 1759 // Check for data-use outside of loop - at least one of OLD or USE 1760 // must not be a CFG node. 1761 if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { 1762 1763 // If the Data use is an IF, that means we have an IF outside of the 1764 // loop that is switching on a condition that is set inside of the 1765 // loop. Happens if people set a loop-exit flag; then test the flag 1766 // in the loop to break the loop, then test is again outside of the 1767 // loop to determine which way the loop exited. 1768 // Loop predicate If node connects to Bool node through Opaque1 node. 1769 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use) || use->Opcode() == Op_Opaque4) { 1770 // Since this code is highly unlikely, we lazily build the worklist 1771 // of such Nodes to go split. 1772 if (!split_if_set) { 1773 split_if_set = new Node_List(area); 1774 } 1775 split_if_set->push(use); 1776 } 1777 if (use->is_Bool()) { 1778 if (!split_bool_set) { 1779 split_bool_set = new Node_List(area); 1780 } 1781 split_bool_set->push(use); 1782 } 1783 if (use->Opcode() == Op_CreateEx) { 1784 if (!split_cex_set) { 1785 split_cex_set = new Node_List(area); 1786 } 1787 split_cex_set->push(use); 1788 } 1789 1790 1791 // Get "block" use is in 1792 uint idx = 0; 1793 while( use->in(idx) != old ) idx++; 1794 Node *prev = use->is_CFG() ? use : get_ctrl(use); 1795 assert( !loop->is_member( get_loop( prev ) ), "" ); 1796 Node *cfg = prev->_idx >= new_counter 1797 ? prev->in(2) 1798 : idom(prev); 1799 if( use->is_Phi() ) // Phi use is in prior block 1800 cfg = prev->in(idx); // NOT in block of Phi itself 1801 if (cfg->is_top()) { // Use is dead? 1802 _igvn.replace_input_of(use, idx, C->top()); 1803 continue; 1804 } 1805 1806 while( !loop->is_member( get_loop( cfg ) ) ) { 1807 prev = cfg; 1808 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); 1809 } 1810 // If the use occurs after merging several exits from the loop, then 1811 // old value must have dominated all those exits. Since the same old 1812 // value was used on all those exits we did not need a Phi at this 1813 // merge point. NOW we do need a Phi here. Each loop exit value 1814 // is now merged with the peeled body exit; each exit gets its own 1815 // private Phi and those Phis need to be merged here. 1816 Node *phi; 1817 if( prev->is_Region() ) { 1818 if( idx == 0 ) { // Updating control edge? 1819 phi = prev; // Just use existing control 1820 } else { // Else need a new Phi 1821 phi = PhiNode::make( prev, old ); 1822 // Now recursively fix up the new uses of old! 1823 for( uint i = 1; i < prev->req(); i++ ) { 1824 worklist.push(phi); // Onto worklist once for each 'old' input 1825 } 1826 } 1827 } else { 1828 // Get new RegionNode merging old and new loop exits 1829 prev = old_new[prev->_idx]; 1830 assert( prev, "just made this in step 7" ); 1831 if( idx == 0 ) { // Updating control edge? 1832 phi = prev; // Just use existing control 1833 } else { // Else need a new Phi 1834 // Make a new Phi merging data values properly 1835 phi = PhiNode::make( prev, old ); 1836 phi->set_req( 1, nnn ); 1837 } 1838 } 1839 // If inserting a new Phi, check for prior hits 1840 if( idx != 0 ) { 1841 Node *hit = _igvn.hash_find_insert(phi); 1842 if( hit == NULL ) { 1843 _igvn.register_new_node_with_optimizer(phi); // Register new phi 1844 } else { // or 1845 // Remove the new phi from the graph and use the hit 1846 _igvn.remove_dead_node(phi); 1847 phi = hit; // Use existing phi 1848 } 1849 set_ctrl(phi, prev); 1850 } 1851 // Make 'use' use the Phi instead of the old loop body exit value 1852 _igvn.replace_input_of(use, idx, phi); 1853 if( use->_idx >= new_counter ) { // If updating new phis 1854 // Not needed for correctness, but prevents a weak assert 1855 // in AddPNode from tripping (when we end up with different 1856 // base & derived Phis that will become the same after 1857 // IGVN does CSE). 1858 Node *hit = _igvn.hash_find_insert(use); 1859 if( hit ) // Go ahead and re-hash for hits. 1860 _igvn.replace_node( use, hit ); 1861 } 1862 1863 // If 'use' was in the loop-exit block, it now needs to be sunk 1864 // below the post-loop merge point. 1865 sink_use( use, prev ); 1866 } 1867 } 1868 } 1869 1870 // Check for IFs that need splitting/cloning. Happens if an IF outside of 1871 // the loop uses a condition set in the loop. The original IF probably 1872 // takes control from one or more OLD Regions (which in turn get from NEW 1873 // Regions). In any case, there will be a set of Phis for each merge point 1874 // from the IF up to where the original BOOL def exists the loop. 1875 if (split_if_set) { 1876 while (split_if_set->size()) { 1877 Node *iff = split_if_set->pop(); 1878 if (iff->in(1)->is_Phi()) { 1879 Node *b = clone_iff(iff->in(1)->as_Phi(), loop); 1880 _igvn.replace_input_of(iff, 1, b); 1881 } 1882 } 1883 } 1884 if (split_bool_set) { 1885 while (split_bool_set->size()) { 1886 Node *b = split_bool_set->pop(); 1887 Node *phi = b->in(1); 1888 assert(phi->is_Phi(), ""); 1889 CmpNode *cmp = clone_bool((PhiNode*)phi, loop); 1890 _igvn.replace_input_of(b, 1, cmp); 1891 } 1892 } 1893 if (split_cex_set) { 1894 while (split_cex_set->size()) { 1895 Node *b = split_cex_set->pop(); 1896 assert(b->in(0)->is_Region(), ""); 1897 assert(b->in(1)->is_Phi(), ""); 1898 assert(b->in(0)->in(0) == b->in(1)->in(0), ""); 1899 split_up(b, b->in(0), NULL); 1900 } 1901 } 1902 1903 } 1904 1905 1906 //---------------------- stride_of_possible_iv ------------------------------------- 1907 // Looks for an iff/bool/comp with one operand of the compare 1908 // being a cycle involving an add and a phi, 1909 // with an optional truncation (left-shift followed by a right-shift) 1910 // of the add. Returns zero if not an iv. 1911 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { 1912 Node* trunc1 = NULL; 1913 Node* trunc2 = NULL; 1914 const TypeInt* ttype = NULL; 1915 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { 1916 return 0; 1917 } 1918 BoolNode* bl = iff->in(1)->as_Bool(); 1919 Node* cmp = bl->in(1); 1920 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) { 1921 return 0; 1922 } 1923 // Must have an invariant operand 1924 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { 1925 return 0; 1926 } 1927 Node* add2 = NULL; 1928 Node* cmp1 = cmp->in(1); 1929 if (cmp1->is_Phi()) { 1930 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) 1931 Node* phi = cmp1; 1932 for (uint i = 1; i < phi->req(); i++) { 1933 Node* in = phi->in(i); 1934 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, 1935 &trunc1, &trunc2, &ttype); 1936 if (add && add->in(1) == phi) { 1937 add2 = add->in(2); 1938 break; 1939 } 1940 } 1941 } else { 1942 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) 1943 Node* addtrunc = cmp1; 1944 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, 1945 &trunc1, &trunc2, &ttype); 1946 if (add && add->in(1)->is_Phi()) { 1947 Node* phi = add->in(1); 1948 for (uint i = 1; i < phi->req(); i++) { 1949 if (phi->in(i) == addtrunc) { 1950 add2 = add->in(2); 1951 break; 1952 } 1953 } 1954 } 1955 } 1956 if (add2 != NULL) { 1957 const TypeInt* add2t = _igvn.type(add2)->is_int(); 1958 if (add2t->is_con()) { 1959 return add2t->get_con(); 1960 } 1961 } 1962 return 0; 1963 } 1964 1965 1966 //---------------------- stay_in_loop ------------------------------------- 1967 // Return the (unique) control output node that's in the loop (if it exists.) 1968 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { 1969 Node* unique = NULL; 1970 if (!n) return NULL; 1971 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1972 Node* use = n->fast_out(i); 1973 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { 1974 if (unique != NULL) { 1975 return NULL; 1976 } 1977 unique = use; 1978 } 1979 } 1980 return unique; 1981 } 1982 1983 //------------------------------ register_node ------------------------------------- 1984 // Utility to register node "n" with PhaseIdealLoop 1985 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { 1986 _igvn.register_new_node_with_optimizer(n); 1987 loop->_body.push(n); 1988 if (n->is_CFG()) { 1989 set_loop(n, loop); 1990 set_idom(n, pred, ddepth); 1991 } else { 1992 set_ctrl(n, pred); 1993 } 1994 } 1995 1996 //------------------------------ proj_clone ------------------------------------- 1997 // Utility to create an if-projection 1998 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { 1999 ProjNode* c = p->clone()->as_Proj(); 2000 c->set_req(0, iff); 2001 return c; 2002 } 2003 2004 //------------------------------ short_circuit_if ------------------------------------- 2005 // Force the iff control output to be the live_proj 2006 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { 2007 guarantee(live_proj != NULL, "null projection"); 2008 int proj_con = live_proj->_con; 2009 assert(proj_con == 0 || proj_con == 1, "false or true projection"); 2010 Node *con = _igvn.intcon(proj_con); 2011 set_ctrl(con, C->root()); 2012 if (iff) { 2013 iff->set_req(1, con); 2014 } 2015 return con; 2016 } 2017 2018 //------------------------------ insert_if_before_proj ------------------------------------- 2019 // Insert a new if before an if projection (* - new node) 2020 // 2021 // before 2022 // if(test) 2023 // / \ 2024 // v v 2025 // other-proj proj (arg) 2026 // 2027 // after 2028 // if(test) 2029 // / \ 2030 // / v 2031 // | * proj-clone 2032 // v | 2033 // other-proj v 2034 // * new_if(relop(cmp[IU](left,right))) 2035 // / \ 2036 // v v 2037 // * new-proj proj 2038 // (returned) 2039 // 2040 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { 2041 IfNode* iff = proj->in(0)->as_If(); 2042 IdealLoopTree *loop = get_loop(proj); 2043 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 2044 int ddepth = dom_depth(proj); 2045 2046 _igvn.rehash_node_delayed(iff); 2047 _igvn.rehash_node_delayed(proj); 2048 2049 proj->set_req(0, NULL); // temporary disconnect 2050 ProjNode* proj2 = proj_clone(proj, iff); 2051 register_node(proj2, loop, iff, ddepth); 2052 2053 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right); 2054 register_node(cmp, loop, proj2, ddepth); 2055 2056 BoolNode* bol = new BoolNode(cmp, relop); 2057 register_node(bol, loop, proj2, ddepth); 2058 2059 int opcode = iff->Opcode(); 2060 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode"); 2061 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt): 2062 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt); 2063 register_node(new_if, loop, proj2, ddepth); 2064 2065 proj->set_req(0, new_if); // reattach 2066 set_idom(proj, new_if, ddepth); 2067 2068 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); 2069 guarantee(new_exit != NULL, "null exit node"); 2070 register_node(new_exit, get_loop(other_proj), new_if, ddepth); 2071 2072 return new_exit; 2073 } 2074 2075 //------------------------------ insert_region_before_proj ------------------------------------- 2076 // Insert a region before an if projection (* - new node) 2077 // 2078 // before 2079 // if(test) 2080 // / | 2081 // v | 2082 // proj v 2083 // other-proj 2084 // 2085 // after 2086 // if(test) 2087 // / | 2088 // v | 2089 // * proj-clone v 2090 // | other-proj 2091 // v 2092 // * new-region 2093 // | 2094 // v 2095 // * dum_if 2096 // / \ 2097 // v \ 2098 // * dum-proj v 2099 // proj 2100 // 2101 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { 2102 IfNode* iff = proj->in(0)->as_If(); 2103 IdealLoopTree *loop = get_loop(proj); 2104 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 2105 int ddepth = dom_depth(proj); 2106 2107 _igvn.rehash_node_delayed(iff); 2108 _igvn.rehash_node_delayed(proj); 2109 2110 proj->set_req(0, NULL); // temporary disconnect 2111 ProjNode* proj2 = proj_clone(proj, iff); 2112 register_node(proj2, loop, iff, ddepth); 2113 2114 RegionNode* reg = new RegionNode(2); 2115 reg->set_req(1, proj2); 2116 register_node(reg, loop, iff, ddepth); 2117 2118 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); 2119 register_node(dum_if, loop, reg, ddepth); 2120 2121 proj->set_req(0, dum_if); // reattach 2122 set_idom(proj, dum_if, ddepth); 2123 2124 ProjNode* dum_proj = proj_clone(other_proj, dum_if); 2125 register_node(dum_proj, loop, dum_if, ddepth); 2126 2127 return reg; 2128 } 2129 2130 //------------------------------ insert_cmpi_loop_exit ------------------------------------- 2131 // Clone a signed compare loop exit from an unsigned compare and 2132 // insert it before the unsigned cmp on the stay-in-loop path. 2133 // All new nodes inserted in the dominator tree between the original 2134 // if and it's projections. The original if test is replaced with 2135 // a constant to force the stay-in-loop path. 2136 // 2137 // This is done to make sure that the original if and it's projections 2138 // still dominate the same set of control nodes, that the ctrl() relation 2139 // from data nodes to them is preserved, and that their loop nesting is 2140 // preserved. 2141 // 2142 // before 2143 // if(i <u limit) unsigned compare loop exit 2144 // / | 2145 // v v 2146 // exit-proj stay-in-loop-proj 2147 // 2148 // after 2149 // if(stay-in-loop-const) original if 2150 // / | 2151 // / v 2152 // / if(i < limit) new signed test 2153 // / / | 2154 // / / v 2155 // / / if(i <u limit) new cloned unsigned test 2156 // / / / | 2157 // v v v | 2158 // region | 2159 // | | 2160 // dum-if | 2161 // / | | 2162 // ether | | 2163 // v v 2164 // exit-proj stay-in-loop-proj 2165 // 2166 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { 2167 const bool Signed = true; 2168 const bool Unsigned = false; 2169 2170 BoolNode* bol = if_cmpu->in(1)->as_Bool(); 2171 if (bol->_test._test != BoolTest::lt) return NULL; 2172 CmpNode* cmpu = bol->in(1)->as_Cmp(); 2173 if (cmpu->Opcode() != Op_CmpU) return NULL; 2174 int stride = stride_of_possible_iv(if_cmpu); 2175 if (stride == 0) return NULL; 2176 2177 Node* lp_proj = stay_in_loop(if_cmpu, loop); 2178 guarantee(lp_proj != NULL, "null loop node"); 2179 2180 ProjNode* lp_continue = lp_proj->as_Proj(); 2181 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); 2182 2183 Node* limit = NULL; 2184 if (stride > 0) { 2185 limit = cmpu->in(2); 2186 } else { 2187 limit = _igvn.makecon(TypeInt::ZERO); 2188 set_ctrl(limit, C->root()); 2189 } 2190 // Create a new region on the exit path 2191 RegionNode* reg = insert_region_before_proj(lp_exit); 2192 guarantee(reg != NULL, "null region node"); 2193 2194 // Clone the if-cmpu-true-false using a signed compare 2195 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; 2196 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); 2197 reg->add_req(cmpi_exit); 2198 2199 // Clone the if-cmpu-true-false 2200 BoolTest::mask rel_u = bol->_test._test; 2201 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); 2202 reg->add_req(cmpu_exit); 2203 2204 // Force original if to stay in loop. 2205 short_circuit_if(if_cmpu, lp_continue); 2206 2207 return cmpi_exit->in(0)->as_If(); 2208 } 2209 2210 //------------------------------ remove_cmpi_loop_exit ------------------------------------- 2211 // Remove a previously inserted signed compare loop exit. 2212 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { 2213 Node* lp_proj = stay_in_loop(if_cmp, loop); 2214 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && 2215 stay_in_loop(lp_proj, loop)->is_If() && 2216 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); 2217 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); 2218 set_ctrl(con, C->root()); 2219 if_cmp->set_req(1, con); 2220 } 2221 2222 //------------------------------ scheduled_nodelist ------------------------------------- 2223 // Create a post order schedule of nodes that are in the 2224 // "member" set. The list is returned in "sched". 2225 // The first node in "sched" is the loop head, followed by 2226 // nodes which have no inputs in the "member" set, and then 2227 // followed by the nodes that have an immediate input dependence 2228 // on a node in "sched". 2229 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { 2230 2231 assert(member.test(loop->_head->_idx), "loop head must be in member set"); 2232 Arena *a = Thread::current()->resource_area(); 2233 VectorSet visited(a); 2234 Node_Stack nstack(a, loop->_body.size()); 2235 2236 Node* n = loop->_head; // top of stack is cached in "n" 2237 uint idx = 0; 2238 visited.set(n->_idx); 2239 2240 // Initially push all with no inputs from within member set 2241 for(uint i = 0; i < loop->_body.size(); i++ ) { 2242 Node *elt = loop->_body.at(i); 2243 if (member.test(elt->_idx)) { 2244 bool found = false; 2245 for (uint j = 0; j < elt->req(); j++) { 2246 Node* def = elt->in(j); 2247 if (def && member.test(def->_idx) && def != elt) { 2248 found = true; 2249 break; 2250 } 2251 } 2252 if (!found && elt != loop->_head) { 2253 nstack.push(n, idx); 2254 n = elt; 2255 assert(!visited.test(n->_idx), "not seen yet"); 2256 visited.set(n->_idx); 2257 } 2258 } 2259 } 2260 2261 // traverse out's that are in the member set 2262 while (true) { 2263 if (idx < n->outcnt()) { 2264 Node* use = n->raw_out(idx); 2265 idx++; 2266 if (!visited.test_set(use->_idx)) { 2267 if (member.test(use->_idx)) { 2268 nstack.push(n, idx); 2269 n = use; 2270 idx = 0; 2271 } 2272 } 2273 } else { 2274 // All outputs processed 2275 sched.push(n); 2276 if (nstack.is_empty()) break; 2277 n = nstack.node(); 2278 idx = nstack.index(); 2279 nstack.pop(); 2280 } 2281 } 2282 } 2283 2284 2285 //------------------------------ has_use_in_set ------------------------------------- 2286 // Has a use in the vector set 2287 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { 2288 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2289 Node* use = n->fast_out(j); 2290 if (vset.test(use->_idx)) { 2291 return true; 2292 } 2293 } 2294 return false; 2295 } 2296 2297 2298 //------------------------------ has_use_internal_to_set ------------------------------------- 2299 // Has use internal to the vector set (ie. not in a phi at the loop head) 2300 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { 2301 Node* head = loop->_head; 2302 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2303 Node* use = n->fast_out(j); 2304 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { 2305 return true; 2306 } 2307 } 2308 return false; 2309 } 2310 2311 2312 //------------------------------ clone_for_use_outside_loop ------------------------------------- 2313 // clone "n" for uses that are outside of loop 2314 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { 2315 int cloned = 0; 2316 assert(worklist.size() == 0, "should be empty"); 2317 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2318 Node* use = n->fast_out(j); 2319 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { 2320 worklist.push(use); 2321 } 2322 } 2323 while( worklist.size() ) { 2324 Node *use = worklist.pop(); 2325 if (!has_node(use) || use->in(0) == C->top()) continue; 2326 uint j; 2327 for (j = 0; j < use->req(); j++) { 2328 if (use->in(j) == n) break; 2329 } 2330 assert(j < use->req(), "must be there"); 2331 2332 // clone "n" and insert it between the inputs of "n" and the use outside the loop 2333 Node* n_clone = n->clone(); 2334 _igvn.replace_input_of(use, j, n_clone); 2335 cloned++; 2336 Node* use_c; 2337 if (!use->is_Phi()) { 2338 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); 2339 } else { 2340 // Use in a phi is considered a use in the associated predecessor block 2341 use_c = use->in(0)->in(j); 2342 } 2343 set_ctrl(n_clone, use_c); 2344 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); 2345 get_loop(use_c)->_body.push(n_clone); 2346 _igvn.register_new_node_with_optimizer(n_clone); 2347 #if !defined(PRODUCT) 2348 if (TracePartialPeeling) { 2349 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); 2350 } 2351 #endif 2352 } 2353 return cloned; 2354 } 2355 2356 2357 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- 2358 // clone "n" for special uses that are in the not_peeled region. 2359 // If these def-uses occur in separate blocks, the code generator 2360 // marks the method as not compilable. For example, if a "BoolNode" 2361 // is in a different basic block than the "IfNode" that uses it, then 2362 // the compilation is aborted in the code generator. 2363 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, 2364 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { 2365 if (n->is_Phi() || n->is_Load()) { 2366 return; 2367 } 2368 assert(worklist.size() == 0, "should be empty"); 2369 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2370 Node* use = n->fast_out(j); 2371 if ( not_peel.test(use->_idx) && 2372 (use->is_If() || use->is_CMove() || use->is_Bool()) && 2373 use->in(1) == n) { 2374 worklist.push(use); 2375 } 2376 } 2377 if (worklist.size() > 0) { 2378 // clone "n" and insert it between inputs of "n" and the use 2379 Node* n_clone = n->clone(); 2380 loop->_body.push(n_clone); 2381 _igvn.register_new_node_with_optimizer(n_clone); 2382 set_ctrl(n_clone, get_ctrl(n)); 2383 sink_list.push(n_clone); 2384 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. 2385 #if !defined(PRODUCT) 2386 if (TracePartialPeeling) { 2387 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); 2388 } 2389 #endif 2390 while( worklist.size() ) { 2391 Node *use = worklist.pop(); 2392 _igvn.rehash_node_delayed(use); 2393 for (uint j = 1; j < use->req(); j++) { 2394 if (use->in(j) == n) { 2395 use->set_req(j, n_clone); 2396 } 2397 } 2398 } 2399 } 2400 } 2401 2402 2403 //------------------------------ insert_phi_for_loop ------------------------------------- 2404 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist 2405 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { 2406 Node *phi = PhiNode::make(lp, back_edge_val); 2407 phi->set_req(LoopNode::EntryControl, lp_entry_val); 2408 // Use existing phi if it already exists 2409 Node *hit = _igvn.hash_find_insert(phi); 2410 if( hit == NULL ) { 2411 _igvn.register_new_node_with_optimizer(phi); 2412 set_ctrl(phi, lp); 2413 } else { 2414 // Remove the new phi from the graph and use the hit 2415 _igvn.remove_dead_node(phi); 2416 phi = hit; 2417 } 2418 _igvn.replace_input_of(use, idx, phi); 2419 } 2420 2421 #ifdef ASSERT 2422 //------------------------------ is_valid_loop_partition ------------------------------------- 2423 // Validate the loop partition sets: peel and not_peel 2424 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, 2425 VectorSet& not_peel ) { 2426 uint i; 2427 // Check that peel_list entries are in the peel set 2428 for (i = 0; i < peel_list.size(); i++) { 2429 if (!peel.test(peel_list.at(i)->_idx)) { 2430 return false; 2431 } 2432 } 2433 // Check at loop members are in one of peel set or not_peel set 2434 for (i = 0; i < loop->_body.size(); i++ ) { 2435 Node *def = loop->_body.at(i); 2436 uint di = def->_idx; 2437 // Check that peel set elements are in peel_list 2438 if (peel.test(di)) { 2439 if (not_peel.test(di)) { 2440 return false; 2441 } 2442 // Must be in peel_list also 2443 bool found = false; 2444 for (uint j = 0; j < peel_list.size(); j++) { 2445 if (peel_list.at(j)->_idx == di) { 2446 found = true; 2447 break; 2448 } 2449 } 2450 if (!found) { 2451 return false; 2452 } 2453 } else if (not_peel.test(di)) { 2454 if (peel.test(di)) { 2455 return false; 2456 } 2457 } else { 2458 return false; 2459 } 2460 } 2461 return true; 2462 } 2463 2464 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- 2465 // Ensure a use outside of loop is of the right form 2466 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { 2467 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 2468 return (use->is_Phi() && 2469 use_c->is_Region() && use_c->req() == 3 && 2470 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || 2471 use_c->in(exit_idx)->Opcode() == Op_IfFalse || 2472 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && 2473 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); 2474 } 2475 2476 //------------------------------ is_valid_clone_loop_form ------------------------------------- 2477 // Ensure that all uses outside of loop are of the right form 2478 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, 2479 uint orig_exit_idx, uint clone_exit_idx) { 2480 uint len = peel_list.size(); 2481 for (uint i = 0; i < len; i++) { 2482 Node *def = peel_list.at(i); 2483 2484 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 2485 Node *use = def->fast_out(j); 2486 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 2487 if (!loop->is_member(get_loop(use_c))) { 2488 // use is not in the loop, check for correct structure 2489 if (use->in(0) == def) { 2490 // Okay 2491 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { 2492 return false; 2493 } 2494 } 2495 } 2496 } 2497 return true; 2498 } 2499 #endif 2500 2501 //------------------------------ partial_peel ------------------------------------- 2502 // Partially peel (aka loop rotation) the top portion of a loop (called 2503 // the peel section below) by cloning it and placing one copy just before 2504 // the new loop head and the other copy at the bottom of the new loop. 2505 // 2506 // before after where it came from 2507 // 2508 // stmt1 stmt1 2509 // loop: stmt2 clone 2510 // stmt2 if condA goto exitA clone 2511 // if condA goto exitA new_loop: new 2512 // stmt3 stmt3 clone 2513 // if !condB goto loop if condB goto exitB clone 2514 // exitB: stmt2 orig 2515 // stmt4 if !condA goto new_loop orig 2516 // exitA: goto exitA 2517 // exitB: 2518 // stmt4 2519 // exitA: 2520 // 2521 // Step 1: find the cut point: an exit test on probable 2522 // induction variable. 2523 // Step 2: schedule (with cloning) operations in the peel 2524 // section that can be executed after the cut into 2525 // the section that is not peeled. This may need 2526 // to clone operations into exit blocks. For 2527 // instance, a reference to A[i] in the not-peel 2528 // section and a reference to B[i] in an exit block 2529 // may cause a left-shift of i by 2 to be placed 2530 // in the peel block. This step will clone the left 2531 // shift into the exit block and sink the left shift 2532 // from the peel to the not-peel section. 2533 // Step 3: clone the loop, retarget the control, and insert 2534 // phis for values that are live across the new loop 2535 // head. This is very dependent on the graph structure 2536 // from clone_loop. It creates region nodes for 2537 // exit control and associated phi nodes for values 2538 // flow out of the loop through that exit. The region 2539 // node is dominated by the clone's control projection. 2540 // So the clone's peel section is placed before the 2541 // new loop head, and the clone's not-peel section is 2542 // forms the top part of the new loop. The original 2543 // peel section forms the tail of the new loop. 2544 // Step 4: update the dominator tree and recompute the 2545 // dominator depth. 2546 // 2547 // orig 2548 // 2549 // stmt1 2550 // | 2551 // v 2552 // loop predicate 2553 // | 2554 // v 2555 // loop<----+ 2556 // | | 2557 // stmt2 | 2558 // | | 2559 // v | 2560 // ifA | 2561 // / | | 2562 // v v | 2563 // false true ^ <-- last_peel 2564 // / | | 2565 // / ===|==cut | 2566 // / stmt3 | <-- first_not_peel 2567 // / | | 2568 // | v | 2569 // v ifB | 2570 // exitA: / \ | 2571 // / \ | 2572 // v v | 2573 // false true | 2574 // / \ | 2575 // / ----+ 2576 // | 2577 // v 2578 // exitB: 2579 // stmt4 2580 // 2581 // 2582 // after clone loop 2583 // 2584 // stmt1 2585 // | 2586 // v 2587 // loop predicate 2588 // / \ 2589 // clone / \ orig 2590 // / \ 2591 // / \ 2592 // v v 2593 // +---->loop loop<----+ 2594 // | | | | 2595 // | stmt2 stmt2 | 2596 // | | | | 2597 // | v v | 2598 // | ifA ifA | 2599 // | | \ / | | 2600 // | v v v v | 2601 // ^ true false false true ^ <-- last_peel 2602 // | | ^ \ / | | 2603 // | cut==|== \ \ / ===|==cut | 2604 // | stmt3 \ \ / stmt3 | <-- first_not_peel 2605 // | | dom | | | | 2606 // | v \ 1v v2 v | 2607 // | ifB regionA ifB | 2608 // | / \ | / \ | 2609 // | / \ v / \ | 2610 // | v v exitA: v v | 2611 // | true false false true | 2612 // | / ^ \ / \ | 2613 // +---- \ \ / ----+ 2614 // dom \ / 2615 // \ 1v v2 2616 // regionB 2617 // | 2618 // v 2619 // exitB: 2620 // stmt4 2621 // 2622 // 2623 // after partial peel 2624 // 2625 // stmt1 2626 // | 2627 // v 2628 // loop predicate 2629 // / 2630 // clone / orig 2631 // / TOP 2632 // / \ 2633 // v v 2634 // TOP->loop loop----+ 2635 // | | | 2636 // stmt2 stmt2 | 2637 // | | | 2638 // v v | 2639 // ifA ifA | 2640 // | \ / | | 2641 // v v v v | 2642 // true false false true | <-- last_peel 2643 // | ^ \ / +------|---+ 2644 // +->newloop \ \ / === ==cut | | 2645 // | stmt3 \ \ / TOP | | 2646 // | | dom | | stmt3 | | <-- first_not_peel 2647 // | v \ 1v v2 v | | 2648 // | ifB regionA ifB ^ v 2649 // | / \ | / \ | | 2650 // | / \ v / \ | | 2651 // | v v exitA: v v | | 2652 // | true false false true | | 2653 // | / ^ \ / \ | | 2654 // | | \ \ / v | | 2655 // | | dom \ / TOP | | 2656 // | | \ 1v v2 | | 2657 // ^ v regionB | | 2658 // | | | | | 2659 // | | v ^ v 2660 // | | exitB: | | 2661 // | | stmt4 | | 2662 // | +------------>-----------------+ | 2663 // | | 2664 // +-----------------<---------------------+ 2665 // 2666 // 2667 // final graph 2668 // 2669 // stmt1 2670 // | 2671 // v 2672 // loop predicate 2673 // | 2674 // v 2675 // stmt2 clone 2676 // | 2677 // v 2678 // ........> ifA clone 2679 // : / | 2680 // dom / | 2681 // : v v 2682 // : false true 2683 // : | | 2684 // : | v 2685 // : | newloop<-----+ 2686 // : | | | 2687 // : | stmt3 clone | 2688 // : | | | 2689 // : | v | 2690 // : | ifB | 2691 // : | / \ | 2692 // : | v v | 2693 // : | false true | 2694 // : | | | | 2695 // : | v stmt2 | 2696 // : | exitB: | | 2697 // : | stmt4 v | 2698 // : | ifA orig | 2699 // : | / \ | 2700 // : | / \ | 2701 // : | v v | 2702 // : | false true | 2703 // : | / \ | 2704 // : v v -----+ 2705 // RegionA 2706 // | 2707 // v 2708 // exitA 2709 // 2710 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { 2711 2712 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only"); 2713 if (!loop->_head->is_Loop()) { 2714 return false; } 2715 2716 LoopNode *head = loop->_head->as_Loop(); 2717 2718 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { 2719 return false; 2720 } 2721 2722 // Check for complex exit control 2723 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { 2724 Node *n = loop->_body.at(ii); 2725 int opc = n->Opcode(); 2726 if (n->is_Call() || 2727 opc == Op_Catch || 2728 opc == Op_CatchProj || 2729 opc == Op_Jump || 2730 opc == Op_JumpProj) { 2731 #if !defined(PRODUCT) 2732 if (TracePartialPeeling) { 2733 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); 2734 } 2735 #endif 2736 return false; 2737 } 2738 } 2739 2740 int dd = dom_depth(head); 2741 2742 // Step 1: find cut point 2743 2744 // Walk up dominators to loop head looking for first loop exit 2745 // which is executed on every path thru loop. 2746 IfNode *peel_if = NULL; 2747 IfNode *peel_if_cmpu = NULL; 2748 2749 Node *iff = loop->tail(); 2750 while( iff != head ) { 2751 if( iff->is_If() ) { 2752 Node *ctrl = get_ctrl(iff->in(1)); 2753 if (ctrl->is_top()) return false; // Dead test on live IF. 2754 // If loop-varying exit-test, check for induction variable 2755 if( loop->is_member(get_loop(ctrl)) && 2756 loop->is_loop_exit(iff) && 2757 is_possible_iv_test(iff)) { 2758 Node* cmp = iff->in(1)->in(1); 2759 if (cmp->Opcode() == Op_CmpI) { 2760 peel_if = iff->as_If(); 2761 } else { 2762 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); 2763 peel_if_cmpu = iff->as_If(); 2764 } 2765 } 2766 } 2767 iff = idom(iff); 2768 } 2769 // Prefer signed compare over unsigned compare. 2770 IfNode* new_peel_if = NULL; 2771 if (peel_if == NULL) { 2772 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { 2773 return false; // No peel point found 2774 } 2775 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); 2776 if (new_peel_if == NULL) { 2777 return false; // No peel point found 2778 } 2779 peel_if = new_peel_if; 2780 } 2781 Node* last_peel = stay_in_loop(peel_if, loop); 2782 Node* first_not_peeled = stay_in_loop(last_peel, loop); 2783 if (first_not_peeled == NULL || first_not_peeled == head) { 2784 return false; 2785 } 2786 2787 #if !defined(PRODUCT) 2788 if (TraceLoopOpts) { 2789 tty->print("PartialPeel "); 2790 loop->dump_head(); 2791 } 2792 2793 if (TracePartialPeeling) { 2794 tty->print_cr("before partial peel one iteration"); 2795 Node_List wl; 2796 Node* t = head->in(2); 2797 while (true) { 2798 wl.push(t); 2799 if (t == head) break; 2800 t = idom(t); 2801 } 2802 while (wl.size() > 0) { 2803 Node* tt = wl.pop(); 2804 tt->dump(); 2805 if (tt == last_peel) tty->print_cr("-- cut --"); 2806 } 2807 } 2808 #endif 2809 ResourceArea *area = Thread::current()->resource_area(); 2810 VectorSet peel(area); 2811 VectorSet not_peel(area); 2812 Node_List peel_list(area); 2813 Node_List worklist(area); 2814 Node_List sink_list(area); 2815 2816 // Set of cfg nodes to peel are those that are executable from 2817 // the head through last_peel. 2818 assert(worklist.size() == 0, "should be empty"); 2819 worklist.push(head); 2820 peel.set(head->_idx); 2821 while (worklist.size() > 0) { 2822 Node *n = worklist.pop(); 2823 if (n != last_peel) { 2824 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2825 Node* use = n->fast_out(j); 2826 if (use->is_CFG() && 2827 loop->is_member(get_loop(use)) && 2828 !peel.test_set(use->_idx)) { 2829 worklist.push(use); 2830 } 2831 } 2832 } 2833 } 2834 2835 // Set of non-cfg nodes to peel are those that are control 2836 // dependent on the cfg nodes. 2837 uint i; 2838 for(i = 0; i < loop->_body.size(); i++ ) { 2839 Node *n = loop->_body.at(i); 2840 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; 2841 if (peel.test(n_c->_idx)) { 2842 peel.set(n->_idx); 2843 } else { 2844 not_peel.set(n->_idx); 2845 } 2846 } 2847 2848 // Step 2: move operations from the peeled section down into the 2849 // not-peeled section 2850 2851 // Get a post order schedule of nodes in the peel region 2852 // Result in right-most operand. 2853 scheduled_nodelist(loop, peel, peel_list ); 2854 2855 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 2856 2857 // For future check for too many new phis 2858 uint old_phi_cnt = 0; 2859 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { 2860 Node* use = head->fast_out(j); 2861 if (use->is_Phi()) old_phi_cnt++; 2862 } 2863 2864 #if !defined(PRODUCT) 2865 if (TracePartialPeeling) { 2866 tty->print_cr("\npeeled list"); 2867 } 2868 #endif 2869 2870 // Evacuate nodes in peel region into the not_peeled region if possible 2871 uint new_phi_cnt = 0; 2872 uint cloned_for_outside_use = 0; 2873 for (i = 0; i < peel_list.size();) { 2874 Node* n = peel_list.at(i); 2875 #if !defined(PRODUCT) 2876 if (TracePartialPeeling) n->dump(); 2877 #endif 2878 bool incr = true; 2879 if ( !n->is_CFG() ) { 2880 2881 if ( has_use_in_set(n, not_peel) ) { 2882 2883 // If not used internal to the peeled region, 2884 // move "n" from peeled to not_peeled region. 2885 2886 if ( !has_use_internal_to_set(n, peel, loop) ) { 2887 2888 // if not pinned and not a load (which maybe anti-dependent on a store) 2889 // and not a CMove (Matcher expects only bool->cmove). 2890 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { 2891 cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist ); 2892 sink_list.push(n); 2893 peel >>= n->_idx; // delete n from peel set. 2894 not_peel <<= n->_idx; // add n to not_peel set. 2895 peel_list.remove(i); 2896 incr = false; 2897 #if !defined(PRODUCT) 2898 if (TracePartialPeeling) { 2899 tty->print_cr("sink to not_peeled region: %d newbb: %d", 2900 n->_idx, get_ctrl(n)->_idx); 2901 } 2902 #endif 2903 } 2904 } else { 2905 // Otherwise check for special def-use cases that span 2906 // the peel/not_peel boundary such as bool->if 2907 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); 2908 new_phi_cnt++; 2909 } 2910 } 2911 } 2912 if (incr) i++; 2913 } 2914 2915 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { 2916 #if !defined(PRODUCT) 2917 if (TracePartialPeeling) { 2918 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", 2919 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); 2920 } 2921 #endif 2922 if (new_peel_if != NULL) { 2923 remove_cmpi_loop_exit(new_peel_if, loop); 2924 } 2925 // Inhibit more partial peeling on this loop 2926 assert(!head->is_partial_peel_loop(), "not partial peeled"); 2927 head->mark_partial_peel_failed(); 2928 if (cloned_for_outside_use > 0) { 2929 // Terminate this round of loop opts because 2930 // the graph outside this loop was changed. 2931 C->set_major_progress(); 2932 return true; 2933 } 2934 return false; 2935 } 2936 2937 // Step 3: clone loop, retarget control, and insert new phis 2938 2939 // Create new loop head for new phis and to hang 2940 // the nodes being moved (sinked) from the peel region. 2941 LoopNode* new_head = new LoopNode(last_peel, last_peel); 2942 new_head->set_unswitch_count(head->unswitch_count()); // Preserve 2943 _igvn.register_new_node_with_optimizer(new_head); 2944 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); 2945 _igvn.replace_input_of(first_not_peeled, 0, new_head); 2946 set_loop(new_head, loop); 2947 loop->_body.push(new_head); 2948 not_peel.set(new_head->_idx); 2949 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); 2950 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); 2951 2952 while (sink_list.size() > 0) { 2953 Node* n = sink_list.pop(); 2954 set_ctrl(n, new_head); 2955 } 2956 2957 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 2958 2959 clone_loop( loop, old_new, dd ); 2960 2961 const uint clone_exit_idx = 1; 2962 const uint orig_exit_idx = 2; 2963 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); 2964 2965 Node* head_clone = old_new[head->_idx]; 2966 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); 2967 Node* orig_tail_clone = head_clone->in(2); 2968 2969 // Add phi if "def" node is in peel set and "use" is not 2970 2971 for(i = 0; i < peel_list.size(); i++ ) { 2972 Node *def = peel_list.at(i); 2973 if (!def->is_CFG()) { 2974 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 2975 Node *use = def->fast_out(j); 2976 if (has_node(use) && use->in(0) != C->top() && 2977 (!peel.test(use->_idx) || 2978 (use->is_Phi() && use->in(0) == head)) ) { 2979 worklist.push(use); 2980 } 2981 } 2982 while( worklist.size() ) { 2983 Node *use = worklist.pop(); 2984 for (uint j = 1; j < use->req(); j++) { 2985 Node* n = use->in(j); 2986 if (n == def) { 2987 2988 // "def" is in peel set, "use" is not in peel set 2989 // or "use" is in the entry boundary (a phi) of the peel set 2990 2991 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; 2992 2993 if ( loop->is_member(get_loop( use_c )) ) { 2994 // use is in loop 2995 if (old_new[use->_idx] != NULL) { // null for dead code 2996 Node* use_clone = old_new[use->_idx]; 2997 _igvn.replace_input_of(use, j, C->top()); 2998 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); 2999 } 3000 } else { 3001 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); 3002 // use is not in the loop, check if the live range includes the cut 3003 Node* lp_if = use_c->in(orig_exit_idx)->in(0); 3004 if (not_peel.test(lp_if->_idx)) { 3005 assert(j == orig_exit_idx, "use from original loop"); 3006 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); 3007 } 3008 } 3009 } 3010 } 3011 } 3012 } 3013 } 3014 3015 // Step 3b: retarget control 3016 3017 // Redirect control to the new loop head if a cloned node in 3018 // the not_peeled region has control that points into the peeled region. 3019 // This necessary because the cloned peeled region will be outside 3020 // the loop. 3021 // from to 3022 // cloned-peeled <---+ 3023 // new_head_clone: | <--+ 3024 // cloned-not_peeled in(0) in(0) 3025 // orig-peeled 3026 3027 for(i = 0; i < loop->_body.size(); i++ ) { 3028 Node *n = loop->_body.at(i); 3029 if (!n->is_CFG() && n->in(0) != NULL && 3030 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { 3031 Node* n_clone = old_new[n->_idx]; 3032 _igvn.replace_input_of(n_clone, 0, new_head_clone); 3033 } 3034 } 3035 3036 // Backedge of the surviving new_head (the clone) is original last_peel 3037 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel); 3038 3039 // Cut first node in original not_peel set 3040 _igvn.rehash_node_delayed(new_head); // Multiple edge updates: 3041 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of 3042 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls 3043 3044 // Copy head_clone back-branch info to original head 3045 // and remove original head's loop entry and 3046 // clone head's back-branch 3047 _igvn.rehash_node_delayed(head); // Multiple edge updates 3048 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); 3049 head->set_req(LoopNode::LoopBackControl, C->top()); 3050 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top()); 3051 3052 // Similarly modify the phis 3053 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { 3054 Node* use = head->fast_out(k); 3055 if (use->is_Phi() && use->outcnt() > 0) { 3056 Node* use_clone = old_new[use->_idx]; 3057 _igvn.rehash_node_delayed(use); // Multiple edge updates 3058 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); 3059 use->set_req(LoopNode::LoopBackControl, C->top()); 3060 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top()); 3061 } 3062 } 3063 3064 // Step 4: update dominator tree and dominator depth 3065 3066 set_idom(head, orig_tail_clone, dd); 3067 recompute_dom_depth(); 3068 3069 // Inhibit more partial peeling on this loop 3070 new_head_clone->set_partial_peel_loop(); 3071 C->set_major_progress(); 3072 loop->record_for_igvn(); 3073 3074 #if !defined(PRODUCT) 3075 if (TracePartialPeeling) { 3076 tty->print_cr("\nafter partial peel one iteration"); 3077 Node_List wl(area); 3078 Node* t = last_peel; 3079 while (true) { 3080 wl.push(t); 3081 if (t == head_clone) break; 3082 t = idom(t); 3083 } 3084 while (wl.size() > 0) { 3085 Node* tt = wl.pop(); 3086 if (tt == head) tty->print_cr("orig head"); 3087 else if (tt == new_head_clone) tty->print_cr("new head"); 3088 else if (tt == head_clone) tty->print_cr("clone head"); 3089 tt->dump(); 3090 } 3091 } 3092 #endif 3093 return true; 3094 } 3095 3096 //------------------------------reorg_offsets---------------------------------- 3097 // Reorganize offset computations to lower register pressure. Mostly 3098 // prevent loop-fallout uses of the pre-incremented trip counter (which are 3099 // then alive with the post-incremented trip counter forcing an extra 3100 // register move) 3101 void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) { 3102 // Perform it only for canonical counted loops. 3103 // Loop's shape could be messed up by iteration_split_impl. 3104 if (!loop->_head->is_CountedLoop()) 3105 return; 3106 if (!loop->_head->as_Loop()->is_valid_counted_loop()) 3107 return; 3108 3109 CountedLoopNode *cl = loop->_head->as_CountedLoop(); 3110 CountedLoopEndNode *cle = cl->loopexit(); 3111 Node *exit = cle->proj_out(false); 3112 Node *phi = cl->phi(); 3113 3114 // Check for the special case of folks using the pre-incremented 3115 // trip-counter on the fall-out path (forces the pre-incremented 3116 // and post-incremented trip counter to be live at the same time). 3117 // Fix this by adjusting to use the post-increment trip counter. 3118 3119 bool progress = true; 3120 while (progress) { 3121 progress = false; 3122 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { 3123 Node* use = phi->fast_out(i); // User of trip-counter 3124 if (!has_ctrl(use)) continue; 3125 Node *u_ctrl = get_ctrl(use); 3126 if (use->is_Phi()) { 3127 u_ctrl = NULL; 3128 for (uint j = 1; j < use->req(); j++) 3129 if (use->in(j) == phi) 3130 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j)); 3131 } 3132 IdealLoopTree *u_loop = get_loop(u_ctrl); 3133 // Look for loop-invariant use 3134 if (u_loop == loop) continue; 3135 if (loop->is_member(u_loop)) continue; 3136 // Check that use is live out the bottom. Assuming the trip-counter 3137 // update is right at the bottom, uses of of the loop middle are ok. 3138 if (dom_lca(exit, u_ctrl) != exit) continue; 3139 // Hit! Refactor use to use the post-incremented tripcounter. 3140 // Compute a post-increment tripcounter. 3141 Node *opaq = new Opaque2Node( C, cle->incr() ); 3142 register_new_node(opaq, exit); 3143 Node *neg_stride = _igvn.intcon(-cle->stride_con()); 3144 set_ctrl(neg_stride, C->root()); 3145 Node *post = new AddINode( opaq, neg_stride); 3146 register_new_node(post, exit); 3147 _igvn.rehash_node_delayed(use); 3148 for (uint j = 1; j < use->req(); j++) { 3149 if (use->in(j) == phi) 3150 use->set_req(j, post); 3151 } 3152 // Since DU info changed, rerun loop 3153 progress = true; 3154 break; 3155 } 3156 } 3157 3158 }