loopopts.cpp revision 9462:231763c1883e
1/* 2 * Copyright (c) 1999, 2015, 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 "opto/addnode.hpp" 28#include "opto/connode.hpp" 29#include "opto/divnode.hpp" 30#include "opto/loopnode.hpp" 31#include "opto/matcher.hpp" 32#include "opto/mulnode.hpp" 33#include "opto/movenode.hpp" 34#include "opto/opaquenode.hpp" 35#include "opto/rootnode.hpp" 36#include "opto/subnode.hpp" 37 38//============================================================================= 39//------------------------------split_thru_phi--------------------------------- 40// Split Node 'n' through merge point if there is enough win. 41Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { 42 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { 43 // ConvI2L may have type information on it which is unsafe to push up 44 // so disable this for now 45 return NULL; 46 } 47 48 int wins = 0; 49 assert(!n->is_CFG(), ""); 50 assert(region->is_Region(), ""); 51 52 const Type* type = n->bottom_type(); 53 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); 54 Node *phi; 55 if (t_oop != NULL && t_oop->is_known_instance_field()) { 56 int iid = t_oop->instance_id(); 57 int index = C->get_alias_index(t_oop); 58 int offset = t_oop->offset(); 59 phi = new PhiNode(region, type, NULL, iid, index, offset); 60 } else { 61 phi = PhiNode::make_blank(region, n); 62 } 63 uint old_unique = C->unique(); 64 for (uint i = 1; i < region->req(); i++) { 65 Node *x; 66 Node* the_clone = NULL; 67 if (region->in(i) == C->top()) { 68 x = C->top(); // Dead path? Use a dead data op 69 } else { 70 x = n->clone(); // Else clone up the data op 71 the_clone = x; // Remember for possible deletion. 72 // Alter data node to use pre-phi inputs 73 if (n->in(0) == region) 74 x->set_req( 0, region->in(i) ); 75 for (uint j = 1; j < n->req(); j++) { 76 Node *in = n->in(j); 77 if (in->is_Phi() && in->in(0) == region) 78 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone 79 } 80 } 81 // Check for a 'win' on some paths 82 const Type *t = x->Value(&_igvn); 83 84 bool singleton = t->singleton(); 85 86 // A TOP singleton indicates that there are no possible values incoming 87 // along a particular edge. In most cases, this is OK, and the Phi will 88 // be eliminated later in an Ideal call. However, we can't allow this to 89 // happen if the singleton occurs on loop entry, as the elimination of 90 // the PhiNode may cause the resulting node to migrate back to a previous 91 // loop iteration. 92 if (singleton && t == Type::TOP) { 93 // Is_Loop() == false does not confirm the absence of a loop (e.g., an 94 // irreducible loop may not be indicated by an affirmative is_Loop()); 95 // therefore, the only top we can split thru a phi is on a backedge of 96 // a loop. 97 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); 98 } 99 100 if (singleton) { 101 wins++; 102 x = ((PhaseGVN&)_igvn).makecon(t); 103 } else { 104 // We now call Identity to try to simplify the cloned node. 105 // Note that some Identity methods call phase->type(this). 106 // Make sure that the type array is big enough for 107 // our new node, even though we may throw the node away. 108 // (Note: This tweaking with igvn only works because x is a new node.) 109 _igvn.set_type(x, t); 110 // If x is a TypeNode, capture any more-precise type permanently into Node 111 // otherwise it will be not updated during igvn->transform since 112 // igvn->type(x) is set to x->Value() already. 113 x->raise_bottom_type(t); 114 Node *y = x->Identity(&_igvn); 115 if (y != x) { 116 wins++; 117 x = y; 118 } else { 119 y = _igvn.hash_find(x); 120 if (y) { 121 wins++; 122 x = y; 123 } else { 124 // Else x is a new node we are keeping 125 // We do not need register_new_node_with_optimizer 126 // because set_type has already been called. 127 _igvn._worklist.push(x); 128 } 129 } 130 } 131 if (x != the_clone && the_clone != NULL) 132 _igvn.remove_dead_node(the_clone); 133 phi->set_req( i, x ); 134 } 135 // Too few wins? 136 if (wins <= policy) { 137 _igvn.remove_dead_node(phi); 138 return NULL; 139 } 140 141 // Record Phi 142 register_new_node( phi, region ); 143 144 for (uint i2 = 1; i2 < phi->req(); i2++) { 145 Node *x = phi->in(i2); 146 // If we commoned up the cloned 'x' with another existing Node, 147 // the existing Node picks up a new use. We need to make the 148 // existing Node occur higher up so it dominates its uses. 149 Node *old_ctrl; 150 IdealLoopTree *old_loop; 151 152 if (x->is_Con()) { 153 // Constant's control is always root. 154 set_ctrl(x, C->root()); 155 continue; 156 } 157 // The occasional new node 158 if (x->_idx >= old_unique) { // Found a new, unplaced node? 159 old_ctrl = NULL; 160 old_loop = NULL; // Not in any prior loop 161 } else { 162 old_ctrl = get_ctrl(x); 163 old_loop = get_loop(old_ctrl); // Get prior loop 164 } 165 // New late point must dominate new use 166 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2)); 167 if (new_ctrl == old_ctrl) // Nothing is changed 168 continue; 169 170 IdealLoopTree *new_loop = get_loop(new_ctrl); 171 172 // Don't move x into a loop if its uses are 173 // outside of loop. Otherwise x will be cloned 174 // for each use outside of this loop. 175 IdealLoopTree *use_loop = get_loop(region); 176 if (!new_loop->is_member(use_loop) && 177 (old_loop == NULL || !new_loop->is_member(old_loop))) { 178 // Take early control, later control will be recalculated 179 // during next iteration of loop optimizations. 180 new_ctrl = get_early_ctrl(x); 181 new_loop = get_loop(new_ctrl); 182 } 183 // Set new location 184 set_ctrl(x, new_ctrl); 185 // If changing loop bodies, see if we need to collect into new body 186 if (old_loop != new_loop) { 187 if (old_loop && !old_loop->_child) 188 old_loop->_body.yank(x); 189 if (!new_loop->_child) 190 new_loop->_body.push(x); // Collect body info 191 } 192 } 193 194 return phi; 195} 196 197//------------------------------dominated_by------------------------------------ 198// Replace the dominated test with an obvious true or false. Place it on the 199// IGVN worklist for later cleanup. Move control-dependent data Nodes on the 200// live path up to the dominating control. 201void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) { 202 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); } 203 204 // prevdom is the dominating projection of the dominating test. 205 assert( iff->is_If(), "" ); 206 assert(iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd || iff->Opcode() == Op_RangeCheck, "Check this code when new subtype is added"); 207 int pop = prevdom->Opcode(); 208 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); 209 if (flip) { 210 if (pop == Op_IfTrue) 211 pop = Op_IfFalse; 212 else 213 pop = Op_IfTrue; 214 } 215 // 'con' is set to true or false to kill the dominated test. 216 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); 217 set_ctrl(con, C->root()); // Constant gets a new use 218 // Hack the dominated test 219 _igvn.replace_input_of(iff, 1, con); 220 221 // If I dont have a reachable TRUE and FALSE path following the IfNode then 222 // I can assume this path reaches an infinite loop. In this case it's not 223 // important to optimize the data Nodes - either the whole compilation will 224 // be tossed or this path (and all data Nodes) will go dead. 225 if (iff->outcnt() != 2) return; 226 227 // Make control-dependent data Nodes on the live path (path that will remain 228 // once the dominated IF is removed) become control-dependent on the 229 // dominating projection. 230 Node* dp = iff->as_If()->proj_out(pop == Op_IfTrue); 231 232 // Loop predicates may have depending checks which should not 233 // be skipped. For example, range check predicate has two checks 234 // for lower and upper bounds. 235 if (dp == NULL) 236 return; 237 238 ProjNode* dp_proj = dp->as_Proj(); 239 ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj(); 240 if (exclude_loop_predicate && 241 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL || 242 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) { 243 // If this is a range check (IfNode::is_range_check), do not 244 // reorder because Compile::allow_range_check_smearing might have 245 // changed the check. 246 return; // Let IGVN transformation change control dependence. 247 } 248 249 IdealLoopTree *old_loop = get_loop(dp); 250 251 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { 252 Node* cd = dp->fast_out(i); // Control-dependent node 253 if (cd->depends_only_on_test()) { 254 assert(cd->in(0) == dp, ""); 255 _igvn.replace_input_of(cd, 0, prevdom); 256 set_early_ctrl(cd); 257 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); 258 if (old_loop != new_loop) { 259 if (!old_loop->_child) old_loop->_body.yank(cd); 260 if (!new_loop->_child) new_loop->_body.push(cd); 261 } 262 --i; 263 --imax; 264 } 265 } 266} 267 268//------------------------------has_local_phi_input---------------------------- 269// Return TRUE if 'n' has Phi inputs from its local block and no other 270// block-local inputs (all non-local-phi inputs come from earlier blocks) 271Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { 272 Node *n_ctrl = get_ctrl(n); 273 // See if some inputs come from a Phi in this block, or from before 274 // this block. 275 uint i; 276 for( i = 1; i < n->req(); i++ ) { 277 Node *phi = n->in(i); 278 if( phi->is_Phi() && phi->in(0) == n_ctrl ) 279 break; 280 } 281 if( i >= n->req() ) 282 return NULL; // No Phi inputs; nowhere to clone thru 283 284 // Check for inputs created between 'n' and the Phi input. These 285 // must split as well; they have already been given the chance 286 // (courtesy of a post-order visit) and since they did not we must 287 // recover the 'cost' of splitting them by being very profitable 288 // when splitting 'n'. Since this is unlikely we simply give up. 289 for( i = 1; i < n->req(); i++ ) { 290 Node *m = n->in(i); 291 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { 292 // We allow the special case of AddP's with no local inputs. 293 // This allows us to split-up address expressions. 294 if (m->is_AddP() && 295 get_ctrl(m->in(2)) != n_ctrl && 296 get_ctrl(m->in(3)) != n_ctrl) { 297 // Move the AddP up to dominating point 298 set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); 299 continue; 300 } 301 return NULL; 302 } 303 } 304 305 return n_ctrl; 306} 307 308//------------------------------remix_address_expressions---------------------- 309// Rework addressing expressions to get the most loop-invariant stuff 310// moved out. We'd like to do all associative operators, but it's especially 311// important (common) to do address expressions. 312Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { 313 if (!has_ctrl(n)) return NULL; 314 Node *n_ctrl = get_ctrl(n); 315 IdealLoopTree *n_loop = get_loop(n_ctrl); 316 317 // See if 'n' mixes loop-varying and loop-invariant inputs and 318 // itself is loop-varying. 319 320 // Only interested in binary ops (and AddP) 321 if( n->req() < 3 || n->req() > 4 ) return NULL; 322 323 Node *n1_ctrl = get_ctrl(n->in( 1)); 324 Node *n2_ctrl = get_ctrl(n->in( 2)); 325 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); 326 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); 327 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); 328 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); 329 330 // Does one of my inputs spin in a tighter loop than self? 331 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || 332 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || 333 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) 334 return NULL; // Leave well enough alone 335 336 // Is at least one of my inputs loop-invariant? 337 if( n1_loop == n_loop && 338 n2_loop == n_loop && 339 n3_loop == n_loop ) 340 return NULL; // No loop-invariant inputs 341 342 343 int n_op = n->Opcode(); 344 345 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). 346 if( n_op == Op_LShiftI ) { 347 // Scale is loop invariant 348 Node *scale = n->in(2); 349 Node *scale_ctrl = get_ctrl(scale); 350 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); 351 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) 352 return NULL; 353 const TypeInt *scale_t = scale->bottom_type()->isa_int(); 354 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) 355 return NULL; // Dont bother with byte/short masking 356 // Add must vary with loop (else shift would be loop-invariant) 357 Node *add = n->in(1); 358 Node *add_ctrl = get_ctrl(add); 359 IdealLoopTree *add_loop = get_loop(add_ctrl); 360 //assert( n_loop == add_loop, "" ); 361 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops 362 363 // Convert I-V into I+ (0-V); same for V-I 364 if( add->Opcode() == Op_SubI && 365 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { 366 Node *zero = _igvn.intcon(0); 367 set_ctrl(zero, C->root()); 368 Node *neg = new SubINode( _igvn.intcon(0), add->in(2) ); 369 register_new_node( neg, get_ctrl(add->in(2) ) ); 370 add = new AddINode( add->in(1), neg ); 371 register_new_node( add, add_ctrl ); 372 } 373 if( add->Opcode() != Op_AddI ) return NULL; 374 // See if one add input is loop invariant 375 Node *add_var = add->in(1); 376 Node *add_var_ctrl = get_ctrl(add_var); 377 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); 378 Node *add_invar = add->in(2); 379 Node *add_invar_ctrl = get_ctrl(add_invar); 380 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); 381 if( add_var_loop == n_loop ) { 382 } else if( add_invar_loop == n_loop ) { 383 // Swap to find the invariant part 384 add_invar = add_var; 385 add_invar_ctrl = add_var_ctrl; 386 add_invar_loop = add_var_loop; 387 add_var = add->in(2); 388 Node *add_var_ctrl = get_ctrl(add_var); 389 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); 390 } else // Else neither input is loop invariant 391 return NULL; 392 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) 393 return NULL; // No invariant part of the add? 394 395 // Yes! Reshape address expression! 396 Node *inv_scale = new LShiftINode( add_invar, scale ); 397 Node *inv_scale_ctrl = 398 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? 399 add_invar_ctrl : scale_ctrl; 400 register_new_node( inv_scale, inv_scale_ctrl ); 401 Node *var_scale = new LShiftINode( add_var, scale ); 402 register_new_node( var_scale, n_ctrl ); 403 Node *var_add = new AddINode( var_scale, inv_scale ); 404 register_new_node( var_add, n_ctrl ); 405 _igvn.replace_node( n, var_add ); 406 return var_add; 407 } 408 409 // Replace (I+V) with (V+I) 410 if( n_op == Op_AddI || 411 n_op == Op_AddL || 412 n_op == Op_AddF || 413 n_op == Op_AddD || 414 n_op == Op_MulI || 415 n_op == Op_MulL || 416 n_op == Op_MulF || 417 n_op == Op_MulD ) { 418 if( n2_loop == n_loop ) { 419 assert( n1_loop != n_loop, "" ); 420 n->swap_edges(1, 2); 421 } 422 } 423 424 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), 425 // but not if I2 is a constant. 426 if( n_op == Op_AddP ) { 427 if( n2_loop == n_loop && n3_loop != n_loop ) { 428 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { 429 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); 430 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); 431 IdealLoopTree *n22loop = get_loop( n22_ctrl ); 432 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); 433 if( n22loop != n_loop && n22loop->is_member(n_loop) && 434 n23_loop == n_loop ) { 435 Node *add1 = new AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); 436 // Stuff new AddP in the loop preheader 437 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); 438 Node *add2 = new AddPNode( n->in(1), add1, n->in(2)->in(3) ); 439 register_new_node( add2, n_ctrl ); 440 _igvn.replace_node( n, add2 ); 441 return add2; 442 } 443 } 444 } 445 446 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) 447 if (n2_loop != n_loop && n3_loop == n_loop) { 448 if (n->in(3)->Opcode() == Op_AddX) { 449 Node *V = n->in(3)->in(1); 450 Node *I = n->in(3)->in(2); 451 if (is_member(n_loop,get_ctrl(V))) { 452 } else { 453 Node *tmp = V; V = I; I = tmp; 454 } 455 if (!is_member(n_loop,get_ctrl(I))) { 456 Node *add1 = new AddPNode(n->in(1), n->in(2), I); 457 // Stuff new AddP in the loop preheader 458 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl)); 459 Node *add2 = new AddPNode(n->in(1), add1, V); 460 register_new_node(add2, n_ctrl); 461 _igvn.replace_node(n, add2); 462 return add2; 463 } 464 } 465 } 466 } 467 468 return NULL; 469} 470 471//------------------------------conditional_move------------------------------- 472// Attempt to replace a Phi with a conditional move. We have some pretty 473// strict profitability requirements. All Phis at the merge point must 474// be converted, so we can remove the control flow. We need to limit the 475// number of c-moves to a small handful. All code that was in the side-arms 476// of the CFG diamond is now speculatively executed. This code has to be 477// "cheap enough". We are pretty much limited to CFG diamonds that merge 478// 1 or 2 items with a total of 1 or 2 ops executed speculatively. 479Node *PhaseIdealLoop::conditional_move( Node *region ) { 480 481 assert(region->is_Region(), "sanity check"); 482 if (region->req() != 3) return NULL; 483 484 // Check for CFG diamond 485 Node *lp = region->in(1); 486 Node *rp = region->in(2); 487 if (!lp || !rp) return NULL; 488 Node *lp_c = lp->in(0); 489 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL; 490 IfNode *iff = lp_c->as_If(); 491 492 // Check for ops pinned in an arm of the diamond. 493 // Can't remove the control flow in this case 494 if (lp->outcnt() > 1) return NULL; 495 if (rp->outcnt() > 1) return NULL; 496 497 IdealLoopTree* r_loop = get_loop(region); 498 assert(r_loop == get_loop(iff), "sanity"); 499 // Always convert to CMOVE if all results are used only outside this loop. 500 bool used_inside_loop = (r_loop == _ltree_root); 501 502 // Check profitability 503 int cost = 0; 504 int phis = 0; 505 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 506 Node *out = region->fast_out(i); 507 if (!out->is_Phi()) continue; // Ignore other control edges, etc 508 phis++; 509 PhiNode* phi = out->as_Phi(); 510 BasicType bt = phi->type()->basic_type(); 511 switch (bt) { 512 case T_DOUBLE: 513 if (C->use_cmove()) { 514 continue; //TODO: maybe we want to add some cost 515 } 516 case T_FLOAT: { 517 cost += Matcher::float_cmove_cost(); // Could be very expensive 518 break; 519 } 520 case T_LONG: { 521 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's 522 } 523 case T_INT: // These all CMOV fine 524 case T_ADDRESS: { // (RawPtr) 525 cost++; 526 break; 527 } 528 case T_NARROWOOP: // Fall through 529 case T_OBJECT: { // Base oops are OK, but not derived oops 530 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); 531 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a 532 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus 533 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we 534 // have a Phi for the base here that we convert to a CMOVE all is well 535 // and good. But if the base is dead, we'll not make a CMOVE. Later 536 // the allocator will have to produce a base by creating a CMOVE of the 537 // relevant bases. This puts the allocator in the business of 538 // manufacturing expensive instructions, generally a bad plan. 539 // Just Say No to Conditionally-Moved Derived Pointers. 540 if (tp && tp->offset() != 0) 541 return NULL; 542 cost++; 543 break; 544 } 545 default: 546 return NULL; // In particular, can't do memory or I/O 547 } 548 // Add in cost any speculative ops 549 for (uint j = 1; j < region->req(); j++) { 550 Node *proj = region->in(j); 551 Node *inp = phi->in(j); 552 if (get_ctrl(inp) == proj) { // Found local op 553 cost++; 554 // Check for a chain of dependent ops; these will all become 555 // speculative in a CMOV. 556 for (uint k = 1; k < inp->req(); k++) 557 if (get_ctrl(inp->in(k)) == proj) 558 cost += ConditionalMoveLimit; // Too much speculative goo 559 } 560 } 561 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. 562 // This will likely Split-If, a higher-payoff operation. 563 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { 564 Node* use = phi->fast_out(k); 565 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr()) 566 cost += ConditionalMoveLimit; 567 // Is there a use inside the loop? 568 // Note: check only basic types since CMoveP is pinned. 569 if (!used_inside_loop && is_java_primitive(bt)) { 570 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use); 571 if (r_loop == u_loop || r_loop->is_member(u_loop)) { 572 used_inside_loop = true; 573 } 574 } 575 } 576 }//for 577 Node* bol = iff->in(1); 578 assert(bol->Opcode() == Op_Bool, ""); 579 int cmp_op = bol->in(1)->Opcode(); 580 // It is expensive to generate flags from a float compare. 581 // Avoid duplicated float compare. 582 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; 583 584 float infrequent_prob = PROB_UNLIKELY_MAG(3); 585 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop. 586 if (used_inside_loop) { 587 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo 588 589 // BlockLayoutByFrequency optimization moves infrequent branch 590 // from hot path. No point in CMOV'ing in such case (110 is used 591 // instead of 100 to take into account not exactness of float value). 592 if (BlockLayoutByFrequency) { 593 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f); 594 } 595 } 596 // Check for highly predictable branch. No point in CMOV'ing if 597 // we are going to predict accurately all the time. 598 if (C->use_cmove() && cmp_op == Op_CmpD) ;//keep going 599 else if (iff->_prob < infrequent_prob || 600 iff->_prob > (1.0f - infrequent_prob)) 601 return NULL; 602 603 // -------------- 604 // Now replace all Phis with CMOV's 605 Node *cmov_ctrl = iff->in(0); 606 uint flip = (lp->Opcode() == Op_IfTrue); 607 while (1) { 608 PhiNode* phi = NULL; 609 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 610 Node *out = region->fast_out(i); 611 if (out->is_Phi()) { 612 phi = out->as_Phi(); 613 break; 614 } 615 } 616 if (phi == NULL) break; 617 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); } 618 // Move speculative ops 619 for (uint j = 1; j < region->req(); j++) { 620 Node *proj = region->in(j); 621 Node *inp = phi->in(j); 622 if (get_ctrl(inp) == proj) { // Found local op 623#ifndef PRODUCT 624 if (PrintOpto && VerifyLoopOptimizations) { 625 tty->print(" speculate: "); 626 inp->dump(); 627 } 628#endif 629 set_ctrl(inp, cmov_ctrl); 630 } 631 } 632 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi)); 633 register_new_node( cmov, cmov_ctrl ); 634 _igvn.replace_node( phi, cmov ); 635#ifndef PRODUCT 636 if (TraceLoopOpts) { 637 tty->print("CMOV "); 638 r_loop->dump_head(); 639 if (Verbose) { 640 bol->in(1)->dump(1); 641 cmov->dump(1); 642 } 643 } 644 if (VerifyLoopOptimizations) verify(); 645#endif 646 } 647 648 // The useless CFG diamond will fold up later; see the optimization in 649 // RegionNode::Ideal. 650 _igvn._worklist.push(region); 651 652 return iff->in(1); 653} 654 655static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) { 656 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) { 657 Node* u = m->fast_out(i); 658 if (u->is_CFG()) { 659 if (u->Opcode() == Op_NeverBranch) { 660 u = ((NeverBranchNode*)u)->proj_out(0); 661 enqueue_cfg_uses(u, wq); 662 } else { 663 wq.push(u); 664 } 665 } 666 } 667} 668 669// Try moving a store out of a loop, right before the loop 670Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) { 671 // Store has to be first in the loop body 672 IdealLoopTree *n_loop = get_loop(n_ctrl); 673 if (n->is_Store() && n_loop != _ltree_root && n_loop->is_loop() && n->in(0) != NULL) { 674 Node* address = n->in(MemNode::Address); 675 Node* value = n->in(MemNode::ValueIn); 676 Node* mem = n->in(MemNode::Memory); 677 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 678 IdealLoopTree* value_loop = get_loop(get_ctrl(value)); 679 680 // - address and value must be loop invariant 681 // - memory must be a memory Phi for the loop 682 // - Store must be the only store on this memory slice in the 683 // loop: if there's another store following this one then value 684 // written at iteration i by the second store could be overwritten 685 // at iteration i+n by the first store: it's not safe to move the 686 // first store out of the loop 687 // - nothing must observe the memory Phi: it guarantees no read 688 // before the store, we are also guaranteed the store post 689 // dominates the loop head (ignoring a possible early 690 // exit). Otherwise there would be extra Phi involved between the 691 // loop's Phi and the store. 692 // - there must be no early exit from the loop before the Store 693 // (such an exit most of the time would be an extra use of the 694 // memory Phi but sometimes is a bottom memory Phi that takes the 695 // store as input). 696 697 if (!n_loop->is_member(address_loop) && 698 !n_loop->is_member(value_loop) && 699 mem->is_Phi() && mem->in(0) == n_loop->_head && 700 mem->outcnt() == 1 && 701 mem->in(LoopNode::LoopBackControl) == n) { 702 703 assert(n_loop->_tail != NULL, "need a tail"); 704 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop"); 705 706 // Verify that there's no early exit of the loop before the store. 707 bool ctrl_ok = false; 708 { 709 // Follow control from loop head until n, we exit the loop or 710 // we reach the tail 711 ResourceMark rm; 712 Unique_Node_List wq; 713 wq.push(n_loop->_head); 714 715 for (uint next = 0; next < wq.size(); ++next) { 716 Node *m = wq.at(next); 717 if (m == n->in(0)) { 718 ctrl_ok = true; 719 continue; 720 } 721 assert(!has_ctrl(m), "should be CFG"); 722 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) { 723 ctrl_ok = false; 724 break; 725 } 726 enqueue_cfg_uses(m, wq); 727 if (wq.size() > 10) { 728 ctrl_ok = false; 729 break; 730 } 731 } 732 } 733 if (ctrl_ok) { 734 // move the Store 735 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem); 736 _igvn.replace_input_of(n, 0, n_loop->_head->in(LoopNode::EntryControl)); 737 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl)); 738 // Disconnect the phi now. An empty phi can confuse other 739 // optimizations in this pass of loop opts. 740 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl)); 741 n_loop->_body.yank(mem); 742 743 IdealLoopTree* new_loop = get_loop(n->in(0)); 744 set_ctrl_and_loop(n, n->in(0)); 745 746 return n; 747 } 748 } 749 } 750 return NULL; 751} 752 753// Try moving a store out of a loop, right after the loop 754void PhaseIdealLoop::try_move_store_after_loop(Node* n) { 755 if (n->is_Store() && n->in(0) != NULL) { 756 Node *n_ctrl = get_ctrl(n); 757 IdealLoopTree *n_loop = get_loop(n_ctrl); 758 // Store must be in a loop 759 if (n_loop != _ltree_root && !n_loop->_irreducible) { 760 Node* address = n->in(MemNode::Address); 761 Node* value = n->in(MemNode::ValueIn); 762 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 763 // address must be loop invariant 764 if (!n_loop->is_member(address_loop)) { 765 // Store must be last on this memory slice in the loop and 766 // nothing in the loop must observe it 767 Node* phi = NULL; 768 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 769 Node* u = n->fast_out(i); 770 if (has_ctrl(u)) { // control use? 771 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); 772 if (!n_loop->is_member(u_loop)) { 773 continue; 774 } 775 if (u->is_Phi() && u->in(0) == n_loop->_head) { 776 assert(_igvn.type(u) == Type::MEMORY, "bad phi"); 777 // multiple phis on the same slice are possible 778 if (phi != NULL) { 779 return; 780 } 781 phi = u; 782 continue; 783 } 784 } 785 return; 786 } 787 if (phi != NULL) { 788 // Nothing in the loop before the store (next iteration) 789 // must observe the stored value 790 bool mem_ok = true; 791 { 792 ResourceMark rm; 793 Unique_Node_List wq; 794 wq.push(phi); 795 for (uint next = 0; next < wq.size() && mem_ok; ++next) { 796 Node *m = wq.at(next); 797 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) { 798 Node* u = m->fast_out(i); 799 if (u->is_Store() || u->is_Phi()) { 800 if (u != n) { 801 wq.push(u); 802 mem_ok = (wq.size() <= 10); 803 } 804 } else { 805 mem_ok = false; 806 break; 807 } 808 } 809 } 810 } 811 if (mem_ok) { 812 // Move the Store out of the loop creating clones along 813 // all paths out of the loop that observe the stored value 814 _igvn.rehash_node_delayed(phi); 815 int count = phi->replace_edge(n, n->in(MemNode::Memory)); 816 assert(count > 0, "inconsistent phi"); 817 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 818 Node* u = n->fast_out(i); 819 Node* c = get_ctrl(u); 820 821 if (u->is_Phi()) { 822 c = u->in(0)->in(u->find_edge(n)); 823 } 824 IdealLoopTree *u_loop = get_loop(c); 825 assert (!n_loop->is_member(u_loop), "only the phi should have been a use in the loop"); 826 while(true) { 827 Node* next_c = find_non_split_ctrl(idom(c)); 828 if (n_loop->is_member(get_loop(next_c))) { 829 break; 830 } 831 c = next_c; 832 } 833 834 Node* st = n->clone(); 835 st->set_req(0, c); 836 _igvn.register_new_node_with_optimizer(st); 837 838 set_ctrl(st, c); 839 IdealLoopTree* new_loop = get_loop(c); 840 assert(new_loop != n_loop, "should be moved out of loop"); 841 if (new_loop->_child == NULL) new_loop->_body.push(st); 842 843 _igvn.replace_input_of(u, u->find_edge(n), st); 844 --imax; 845 --i; 846 } 847 848 849 assert(n->outcnt() == 0, "all uses should be gone"); 850 _igvn.replace_input_of(n, MemNode::Memory, C->top()); 851 // Disconnect the phi now. An empty phi can confuse other 852 // optimizations in this pass of loop opts.. 853 if (phi->in(LoopNode::LoopBackControl) == phi) { 854 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl)); 855 n_loop->_body.yank(phi); 856 } 857 } 858 } 859 } 860 } 861 } 862} 863 864//------------------------------split_if_with_blocks_pre----------------------- 865// Do the real work in a non-recursive function. Data nodes want to be 866// cloned in the pre-order so they can feed each other nicely. 867Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { 868 // Cloning these guys is unlikely to win 869 int n_op = n->Opcode(); 870 if( n_op == Op_MergeMem ) return n; 871 if( n->is_Proj() ) return n; 872 // Do not clone-up CmpFXXX variations, as these are always 873 // followed by a CmpI 874 if( n->is_Cmp() ) return n; 875 // Attempt to use a conditional move instead of a phi/branch 876 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { 877 Node *cmov = conditional_move( n ); 878 if( cmov ) return cmov; 879 } 880 if( n->is_CFG() || n->is_LoadStore() ) 881 return n; 882 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd 883 n_op == Op_Opaque2 ) { 884 if( !C->major_progress() ) // If chance of no more loop opts... 885 _igvn._worklist.push(n); // maybe we'll remove them 886 return n; 887 } 888 889 if( n->is_Con() ) return n; // No cloning for Con nodes 890 891 Node *n_ctrl = get_ctrl(n); 892 if( !n_ctrl ) return n; // Dead node 893 894 Node* res = try_move_store_before_loop(n, n_ctrl); 895 if (res != NULL) { 896 return n; 897 } 898 899 // Attempt to remix address expressions for loop invariants 900 Node *m = remix_address_expressions( n ); 901 if( m ) return m; 902 903 // Determine if the Node has inputs from some local Phi. 904 // Returns the block to clone thru. 905 Node *n_blk = has_local_phi_input( n ); 906 if( !n_blk ) return n; 907 908 // Do not clone the trip counter through on a CountedLoop 909 // (messes up the canonical shape). 910 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; 911 912 // Check for having no control input; not pinned. Allow 913 // dominating control. 914 if (n->in(0)) { 915 Node *dom = idom(n_blk); 916 if (dom_lca(n->in(0), dom) != n->in(0)) { 917 return n; 918 } 919 } 920 // Policy: when is it profitable. You must get more wins than 921 // policy before it is considered profitable. Policy is usually 0, 922 // so 1 win is considered profitable. Big merges will require big 923 // cloning, so get a larger policy. 924 int policy = n_blk->req() >> 2; 925 926 // If the loop is a candidate for range check elimination, 927 // delay splitting through it's phi until a later loop optimization 928 if (n_blk->is_CountedLoop()) { 929 IdealLoopTree *lp = get_loop(n_blk); 930 if (lp && lp->_rce_candidate) { 931 return n; 932 } 933 } 934 935 // Use same limit as split_if_with_blocks_post 936 if( C->live_nodes() > 35000 ) return n; // Method too big 937 938 // Split 'n' through the merge point if it is profitable 939 Node *phi = split_thru_phi( n, n_blk, policy ); 940 if (!phi) return n; 941 942 // Found a Phi to split thru! 943 // Replace 'n' with the new phi 944 _igvn.replace_node( n, phi ); 945 // Moved a load around the loop, 'en-registering' something. 946 if (n_blk->is_Loop() && n->is_Load() && 947 !phi->in(LoopNode::LoopBackControl)->is_Load()) 948 C->set_major_progress(); 949 950 return phi; 951} 952 953static bool merge_point_too_heavy(Compile* C, Node* region) { 954 // Bail out if the region and its phis have too many users. 955 int weight = 0; 956 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 957 weight += region->fast_out(i)->outcnt(); 958 } 959 int nodes_left = C->max_node_limit() - C->live_nodes(); 960 if (weight * 8 > nodes_left) { 961 if (PrintOpto) { 962 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); 963 } 964 return true; 965 } else { 966 return false; 967 } 968} 969 970static bool merge_point_safe(Node* region) { 971 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode 972 // having a PhiNode input. This sidesteps the dangerous case where the split 973 // ConvI2LNode may become TOP if the input Value() does not 974 // overlap the ConvI2L range, leaving a node which may not dominate its 975 // uses. 976 // A better fix for this problem can be found in the BugTraq entry, but 977 // expediency for Mantis demands this hack. 978 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop 979 // split_if_with_blocks from splitting a block because we could not move around 980 // the FastLockNode. 981 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 982 Node* n = region->fast_out(i); 983 if (n->is_Phi()) { 984 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 985 Node* m = n->fast_out(j); 986 if (m->is_FastLock()) 987 return false; 988#ifdef _LP64 989 if (m->Opcode() == Op_ConvI2L) 990 return false; 991#endif 992 } 993 } 994 } 995 return true; 996} 997 998 999//------------------------------place_near_use--------------------------------- 1000// Place some computation next to use but not inside inner loops. 1001// For inner loop uses move it to the preheader area. 1002Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { 1003 IdealLoopTree *u_loop = get_loop( useblock ); 1004 return (u_loop->_irreducible || u_loop->_child) 1005 ? useblock 1006 : u_loop->_head->in(LoopNode::EntryControl); 1007} 1008 1009 1010//------------------------------split_if_with_blocks_post---------------------- 1011// Do the real work in a non-recursive function. CFG hackery wants to be 1012// in the post-order, so it can dirty the I-DOM info and not use the dirtied 1013// info. 1014void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) { 1015 1016 // Cloning Cmp through Phi's involves the split-if transform. 1017 // FastLock is not used by an If 1018 if( n->is_Cmp() && !n->is_FastLock() ) { 1019 if( C->live_nodes() > 35000 ) return; // Method too big 1020 1021 // Do not do 'split-if' if irreducible loops are present. 1022 if( _has_irreducible_loops ) 1023 return; 1024 1025 Node *n_ctrl = get_ctrl(n); 1026 // Determine if the Node has inputs from some local Phi. 1027 // Returns the block to clone thru. 1028 Node *n_blk = has_local_phi_input( n ); 1029 if( n_blk != n_ctrl ) return; 1030 1031 if( merge_point_too_heavy(C, n_ctrl) ) 1032 return; 1033 1034 if( n->outcnt() != 1 ) return; // Multiple bool's from 1 compare? 1035 Node *bol = n->unique_out(); 1036 assert( bol->is_Bool(), "expect a bool here" ); 1037 if( bol->outcnt() != 1 ) return;// Multiple branches from 1 compare? 1038 Node *iff = bol->unique_out(); 1039 1040 // Check some safety conditions 1041 if( iff->is_If() ) { // Classic split-if? 1042 if( iff->in(0) != n_ctrl ) return; // Compare must be in same blk as if 1043 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE 1044 // Can't split CMove with different control edge. 1045 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) return; 1046 if( get_ctrl(iff->in(2)) == n_ctrl || 1047 get_ctrl(iff->in(3)) == n_ctrl ) 1048 return; // Inputs not yet split-up 1049 if ( get_loop(n_ctrl) != get_loop(get_ctrl(iff)) ) { 1050 return; // Loop-invar test gates loop-varying CMOVE 1051 } 1052 } else { 1053 return; // some other kind of node, such as an Allocate 1054 } 1055 1056 // Do not do 'split-if' if some paths are dead. First do dead code 1057 // elimination and then see if its still profitable. 1058 for( uint i = 1; i < n_ctrl->req(); i++ ) 1059 if( n_ctrl->in(i) == C->top() ) 1060 return; 1061 1062 // When is split-if profitable? Every 'win' on means some control flow 1063 // goes dead, so it's almost always a win. 1064 int policy = 0; 1065 // If trying to do a 'Split-If' at the loop head, it is only 1066 // profitable if the cmp folds up on BOTH paths. Otherwise we 1067 // risk peeling a loop forever. 1068 1069 // CNC - Disabled for now. Requires careful handling of loop 1070 // body selection for the cloned code. Also, make sure we check 1071 // for any input path not being in the same loop as n_ctrl. For 1072 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' 1073 // because the alternative loop entry points won't be converted 1074 // into LoopNodes. 1075 IdealLoopTree *n_loop = get_loop(n_ctrl); 1076 for( uint j = 1; j < n_ctrl->req(); j++ ) 1077 if( get_loop(n_ctrl->in(j)) != n_loop ) 1078 return; 1079 1080 // Check for safety of the merge point. 1081 if( !merge_point_safe(n_ctrl) ) { 1082 return; 1083 } 1084 1085 // Split compare 'n' through the merge point if it is profitable 1086 Node *phi = split_thru_phi( n, n_ctrl, policy ); 1087 if( !phi ) return; 1088 1089 // Found a Phi to split thru! 1090 // Replace 'n' with the new phi 1091 _igvn.replace_node( n, phi ); 1092 1093 // Now split the bool up thru the phi 1094 Node *bolphi = split_thru_phi( bol, n_ctrl, -1 ); 1095 guarantee(bolphi != NULL, "null boolean phi node"); 1096 1097 _igvn.replace_node( bol, bolphi ); 1098 assert( iff->in(1) == bolphi, "" ); 1099 1100 if( bolphi->Value(&_igvn)->singleton() ) 1101 return; 1102 1103 // Conditional-move? Must split up now 1104 if( !iff->is_If() ) { 1105 Node *cmovphi = split_thru_phi( iff, n_ctrl, -1 ); 1106 _igvn.replace_node( iff, cmovphi ); 1107 return; 1108 } 1109 1110 // Now split the IF 1111 do_split_if( iff ); 1112 return; 1113 } 1114 1115 // Check for an IF ready to split; one that has its 1116 // condition codes input coming from a Phi at the block start. 1117 int n_op = n->Opcode(); 1118 1119 // Check for an IF being dominated by another IF same test 1120 if (n_op == Op_If || 1121 n_op == Op_RangeCheck) { 1122 Node *bol = n->in(1); 1123 uint max = bol->outcnt(); 1124 // Check for same test used more than once? 1125 if (max > 1 && bol->is_Bool()) { 1126 // Search up IDOMs to see if this IF is dominated. 1127 Node *cutoff = get_ctrl(bol); 1128 1129 // Now search up IDOMs till cutoff, looking for a dominating test 1130 Node *prevdom = n; 1131 Node *dom = idom(prevdom); 1132 while (dom != cutoff) { 1133 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) { 1134 // Replace the dominated test with an obvious true or false. 1135 // Place it on the IGVN worklist for later cleanup. 1136 C->set_major_progress(); 1137 dominated_by(prevdom, n, false, true); 1138#ifndef PRODUCT 1139 if( VerifyLoopOptimizations ) verify(); 1140#endif 1141 return; 1142 } 1143 prevdom = dom; 1144 dom = idom(prevdom); 1145 } 1146 } 1147 } 1148 1149 // See if a shared loop-varying computation has no loop-varying uses. 1150 // Happens if something is only used for JVM state in uncommon trap exits, 1151 // like various versions of induction variable+offset. Clone the 1152 // computation per usage to allow it to sink out of the loop. 1153 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) 1154 Node *n_ctrl = get_ctrl(n); 1155 IdealLoopTree *n_loop = get_loop(n_ctrl); 1156 if( n_loop != _ltree_root ) { 1157 DUIterator_Fast imax, i = n->fast_outs(imax); 1158 for (; i < imax; i++) { 1159 Node* u = n->fast_out(i); 1160 if( !has_ctrl(u) ) break; // Found control user 1161 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); 1162 if( u_loop == n_loop ) break; // Found loop-varying use 1163 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop 1164 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 1165 } 1166 bool did_break = (i < imax); // Did we break out of the previous loop? 1167 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! 1168 Node *late_load_ctrl = NULL; 1169 if (n->is_Load()) { 1170 // If n is a load, get and save the result from get_late_ctrl(), 1171 // to be later used in calculating the control for n's clones. 1172 clear_dom_lca_tags(); 1173 late_load_ctrl = get_late_ctrl(n, n_ctrl); 1174 } 1175 // If n is a load, and the late control is the same as the current 1176 // control, then the cloning of n is a pointless exercise, because 1177 // GVN will ensure that we end up where we started. 1178 if (!n->is_Load() || late_load_ctrl != n_ctrl) { 1179 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { 1180 Node *u = n->last_out(j); // Clone private computation per use 1181 _igvn.rehash_node_delayed(u); 1182 Node *x = n->clone(); // Clone computation 1183 Node *x_ctrl = NULL; 1184 if( u->is_Phi() ) { 1185 // Replace all uses of normal nodes. Replace Phi uses 1186 // individually, so the separate Nodes can sink down 1187 // different paths. 1188 uint k = 1; 1189 while( u->in(k) != n ) k++; 1190 u->set_req( k, x ); 1191 // x goes next to Phi input path 1192 x_ctrl = u->in(0)->in(k); 1193 --j; 1194 } else { // Normal use 1195 // Replace all uses 1196 for( uint k = 0; k < u->req(); k++ ) { 1197 if( u->in(k) == n ) { 1198 u->set_req( k, x ); 1199 --j; 1200 } 1201 } 1202 x_ctrl = get_ctrl(u); 1203 } 1204 1205 // Find control for 'x' next to use but not inside inner loops. 1206 // For inner loop uses get the preheader area. 1207 x_ctrl = place_near_use(x_ctrl); 1208 1209 if (n->is_Load()) { 1210 // For loads, add a control edge to a CFG node outside of the loop 1211 // to force them to not combine and return back inside the loop 1212 // during GVN optimization (4641526). 1213 // 1214 // Because we are setting the actual control input, factor in 1215 // the result from get_late_ctrl() so we respect any 1216 // anti-dependences. (6233005). 1217 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); 1218 1219 // Don't allow the control input to be a CFG splitting node. 1220 // Such nodes should only have ProjNodes as outs, e.g. IfNode 1221 // should only have IfTrueNode and IfFalseNode (4985384). 1222 x_ctrl = find_non_split_ctrl(x_ctrl); 1223 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); 1224 1225 x->set_req(0, x_ctrl); 1226 } 1227 register_new_node(x, x_ctrl); 1228 1229 // Some institutional knowledge is needed here: 'x' is 1230 // yanked because if the optimizer runs GVN on it all the 1231 // cloned x's will common up and undo this optimization and 1232 // be forced back in the loop. This is annoying because it 1233 // makes +VerifyOpto report false-positives on progress. I 1234 // tried setting control edges on the x's to force them to 1235 // not combine, but the matching gets worried when it tries 1236 // to fold a StoreP and an AddP together (as part of an 1237 // address expression) and the AddP and StoreP have 1238 // different controls. 1239 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x); 1240 } 1241 _igvn.remove_dead_node(n); 1242 } 1243 } 1244 } 1245 } 1246 1247 try_move_store_after_loop(n); 1248 1249 // Check for Opaque2's who's loop has disappeared - who's input is in the 1250 // same loop nest as their output. Remove 'em, they are no longer useful. 1251 if( n_op == Op_Opaque2 && 1252 n->in(1) != NULL && 1253 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { 1254 _igvn.replace_node( n, n->in(1) ); 1255 } 1256} 1257 1258//------------------------------split_if_with_blocks--------------------------- 1259// Check for aggressive application of 'split-if' optimization, 1260// using basic block level info. 1261void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { 1262 Node *n = C->root(); 1263 visited.set(n->_idx); // first, mark node as visited 1264 // Do pre-visit work for root 1265 n = split_if_with_blocks_pre( n ); 1266 uint cnt = n->outcnt(); 1267 uint i = 0; 1268 while (true) { 1269 // Visit all children 1270 if (i < cnt) { 1271 Node* use = n->raw_out(i); 1272 ++i; 1273 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { 1274 // Now do pre-visit work for this use 1275 use = split_if_with_blocks_pre( use ); 1276 nstack.push(n, i); // Save parent and next use's index. 1277 n = use; // Process all children of current use. 1278 cnt = use->outcnt(); 1279 i = 0; 1280 } 1281 } 1282 else { 1283 // All of n's children have been processed, complete post-processing. 1284 if (cnt != 0 && !n->is_Con()) { 1285 assert(has_node(n), "no dead nodes"); 1286 split_if_with_blocks_post( n ); 1287 } 1288 if (nstack.is_empty()) { 1289 // Finished all nodes on stack. 1290 break; 1291 } 1292 // Get saved parent node and next use's index. Visit the rest of uses. 1293 n = nstack.node(); 1294 cnt = n->outcnt(); 1295 i = nstack.index(); 1296 nstack.pop(); 1297 } 1298 } 1299} 1300 1301 1302//============================================================================= 1303// 1304// C L O N E A L O O P B O D Y 1305// 1306 1307//------------------------------clone_iff-------------------------------------- 1308// Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 1309// "Nearly" because all Nodes have been cloned from the original in the loop, 1310// but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 1311// through the Phi recursively, and return a Bool. 1312BoolNode *PhaseIdealLoop::clone_iff( PhiNode *phi, IdealLoopTree *loop ) { 1313 1314 // Convert this Phi into a Phi merging Bools 1315 uint i; 1316 for( i = 1; i < phi->req(); i++ ) { 1317 Node *b = phi->in(i); 1318 if( b->is_Phi() ) { 1319 _igvn.replace_input_of(phi, i, clone_iff( b->as_Phi(), loop )); 1320 } else { 1321 assert( b->is_Bool(), "" ); 1322 } 1323 } 1324 1325 Node *sample_bool = phi->in(1); 1326 Node *sample_cmp = sample_bool->in(1); 1327 1328 // Make Phis to merge the Cmp's inputs. 1329 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP ); 1330 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP ); 1331 for( i = 1; i < phi->req(); i++ ) { 1332 Node *n1 = phi->in(i)->in(1)->in(1); 1333 Node *n2 = phi->in(i)->in(1)->in(2); 1334 phi1->set_req( i, n1 ); 1335 phi2->set_req( i, n2 ); 1336 phi1->set_type( phi1->type()->meet_speculative(n1->bottom_type())); 1337 phi2->set_type( phi2->type()->meet_speculative(n2->bottom_type())); 1338 } 1339 // See if these Phis have been made before. 1340 // Register with optimizer 1341 Node *hit1 = _igvn.hash_find_insert(phi1); 1342 if( hit1 ) { // Hit, toss just made Phi 1343 _igvn.remove_dead_node(phi1); // Remove new phi 1344 assert( hit1->is_Phi(), "" ); 1345 phi1 = (PhiNode*)hit1; // Use existing phi 1346 } else { // Miss 1347 _igvn.register_new_node_with_optimizer(phi1); 1348 } 1349 Node *hit2 = _igvn.hash_find_insert(phi2); 1350 if( hit2 ) { // Hit, toss just made Phi 1351 _igvn.remove_dead_node(phi2); // Remove new phi 1352 assert( hit2->is_Phi(), "" ); 1353 phi2 = (PhiNode*)hit2; // Use existing phi 1354 } else { // Miss 1355 _igvn.register_new_node_with_optimizer(phi2); 1356 } 1357 // Register Phis with loop/block info 1358 set_ctrl(phi1, phi->in(0)); 1359 set_ctrl(phi2, phi->in(0)); 1360 // Make a new Cmp 1361 Node *cmp = sample_cmp->clone(); 1362 cmp->set_req( 1, phi1 ); 1363 cmp->set_req( 2, phi2 ); 1364 _igvn.register_new_node_with_optimizer(cmp); 1365 set_ctrl(cmp, phi->in(0)); 1366 1367 // Make a new Bool 1368 Node *b = sample_bool->clone(); 1369 b->set_req(1,cmp); 1370 _igvn.register_new_node_with_optimizer(b); 1371 set_ctrl(b, phi->in(0)); 1372 1373 assert( b->is_Bool(), "" ); 1374 return (BoolNode*)b; 1375} 1376 1377//------------------------------clone_bool------------------------------------- 1378// Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 1379// "Nearly" because all Nodes have been cloned from the original in the loop, 1380// but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 1381// through the Phi recursively, and return a Bool. 1382CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { 1383 uint i; 1384 // Convert this Phi into a Phi merging Bools 1385 for( i = 1; i < phi->req(); i++ ) { 1386 Node *b = phi->in(i); 1387 if( b->is_Phi() ) { 1388 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop )); 1389 } else { 1390 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); 1391 } 1392 } 1393 1394 Node *sample_cmp = phi->in(1); 1395 1396 // Make Phis to merge the Cmp's inputs. 1397 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP ); 1398 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP ); 1399 for( uint j = 1; j < phi->req(); j++ ) { 1400 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP 1401 Node *n1, *n2; 1402 if( cmp_top->is_Cmp() ) { 1403 n1 = cmp_top->in(1); 1404 n2 = cmp_top->in(2); 1405 } else { 1406 n1 = n2 = cmp_top; 1407 } 1408 phi1->set_req( j, n1 ); 1409 phi2->set_req( j, n2 ); 1410 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); 1411 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); 1412 } 1413 1414 // See if these Phis have been made before. 1415 // Register with optimizer 1416 Node *hit1 = _igvn.hash_find_insert(phi1); 1417 if( hit1 ) { // Hit, toss just made Phi 1418 _igvn.remove_dead_node(phi1); // Remove new phi 1419 assert( hit1->is_Phi(), "" ); 1420 phi1 = (PhiNode*)hit1; // Use existing phi 1421 } else { // Miss 1422 _igvn.register_new_node_with_optimizer(phi1); 1423 } 1424 Node *hit2 = _igvn.hash_find_insert(phi2); 1425 if( hit2 ) { // Hit, toss just made Phi 1426 _igvn.remove_dead_node(phi2); // Remove new phi 1427 assert( hit2->is_Phi(), "" ); 1428 phi2 = (PhiNode*)hit2; // Use existing phi 1429 } else { // Miss 1430 _igvn.register_new_node_with_optimizer(phi2); 1431 } 1432 // Register Phis with loop/block info 1433 set_ctrl(phi1, phi->in(0)); 1434 set_ctrl(phi2, phi->in(0)); 1435 // Make a new Cmp 1436 Node *cmp = sample_cmp->clone(); 1437 cmp->set_req( 1, phi1 ); 1438 cmp->set_req( 2, phi2 ); 1439 _igvn.register_new_node_with_optimizer(cmp); 1440 set_ctrl(cmp, phi->in(0)); 1441 1442 assert( cmp->is_Cmp(), "" ); 1443 return (CmpNode*)cmp; 1444} 1445 1446//------------------------------sink_use--------------------------------------- 1447// If 'use' was in the loop-exit block, it now needs to be sunk 1448// below the post-loop merge point. 1449void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { 1450 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { 1451 set_ctrl(use, post_loop); 1452 for (DUIterator j = use->outs(); use->has_out(j); j++) 1453 sink_use(use->out(j), post_loop); 1454 } 1455} 1456 1457//------------------------------clone_loop------------------------------------- 1458// 1459// C L O N E A L O O P B O D Y 1460// 1461// This is the basic building block of the loop optimizations. It clones an 1462// entire loop body. It makes an old_new loop body mapping; with this mapping 1463// you can find the new-loop equivalent to an old-loop node. All new-loop 1464// nodes are exactly equal to their old-loop counterparts, all edges are the 1465// same. All exits from the old-loop now have a RegionNode that merges the 1466// equivalent new-loop path. This is true even for the normal "loop-exit" 1467// condition. All uses of loop-invariant old-loop values now come from (one 1468// or more) Phis that merge their new-loop equivalents. 1469// 1470// This operation leaves the graph in an illegal state: there are two valid 1471// control edges coming from the loop pre-header to both loop bodies. I'll 1472// definitely have to hack the graph after running this transform. 1473// 1474// From this building block I will further edit edges to perform loop peeling 1475// or loop unrolling or iteration splitting (Range-Check-Elimination), etc. 1476// 1477// Parameter side_by_size_idom: 1478// When side_by_size_idom is NULL, the dominator tree is constructed for 1479// the clone loop to dominate the original. Used in construction of 1480// pre-main-post loop sequence. 1481// When nonnull, the clone and original are side-by-side, both are 1482// dominated by the side_by_side_idom node. Used in construction of 1483// unswitched loops. 1484void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, 1485 Node* side_by_side_idom) { 1486 1487 if (C->do_vector_loop() && PrintOpto) { 1488 const char* mname = C->method()->name()->as_quoted_ascii(); 1489 if (mname != NULL) { 1490 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname); 1491 } 1492 } 1493 1494 CloneMap& cm = C->clone_map(); 1495 Dict* dict = cm.dict(); 1496 if (C->do_vector_loop()) { 1497 cm.set_clone_idx(cm.max_gen()+1); 1498#ifndef PRODUCT 1499 if (PrintOpto) { 1500 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx()); 1501 loop->dump_head(); 1502 } 1503#endif 1504 } 1505 1506 // Step 1: Clone the loop body. Make the old->new mapping. 1507 uint i; 1508 for( i = 0; i < loop->_body.size(); i++ ) { 1509 Node *old = loop->_body.at(i); 1510 Node *nnn = old->clone(); 1511 old_new.map( old->_idx, nnn ); 1512 if (C->do_vector_loop()) { 1513 cm.verify_insert_and_clone(old, nnn, cm.clone_idx()); 1514 } 1515 _igvn.register_new_node_with_optimizer(nnn); 1516 } 1517 1518 1519 // Step 2: Fix the edges in the new body. If the old input is outside the 1520 // loop use it. If the old input is INside the loop, use the corresponding 1521 // new node instead. 1522 for( i = 0; i < loop->_body.size(); i++ ) { 1523 Node *old = loop->_body.at(i); 1524 Node *nnn = old_new[old->_idx]; 1525 // Fix CFG/Loop controlling the new node 1526 if (has_ctrl(old)) { 1527 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); 1528 } else { 1529 set_loop(nnn, loop->_parent); 1530 if (old->outcnt() > 0) { 1531 set_idom( nnn, old_new[idom(old)->_idx], dd ); 1532 } 1533 } 1534 // Correct edges to the new node 1535 for( uint j = 0; j < nnn->req(); j++ ) { 1536 Node *n = nnn->in(j); 1537 if( n ) { 1538 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); 1539 if( loop->is_member( old_in_loop ) ) 1540 nnn->set_req(j, old_new[n->_idx]); 1541 } 1542 } 1543 _igvn.hash_find_insert(nnn); 1544 } 1545 Node *newhead = old_new[loop->_head->_idx]; 1546 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); 1547 1548 1549 // Step 3: Now fix control uses. Loop varying control uses have already 1550 // been fixed up (as part of all input edges in Step 2). Loop invariant 1551 // control uses must be either an IfFalse or an IfTrue. Make a merge 1552 // point to merge the old and new IfFalse/IfTrue nodes; make the use 1553 // refer to this. 1554 ResourceArea *area = Thread::current()->resource_area(); 1555 Node_List worklist(area); 1556 uint new_counter = C->unique(); 1557 for( i = 0; i < loop->_body.size(); i++ ) { 1558 Node* old = loop->_body.at(i); 1559 if( !old->is_CFG() ) continue; 1560 Node* nnn = old_new[old->_idx]; 1561 1562 // Copy uses to a worklist, so I can munge the def-use info 1563 // with impunity. 1564 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) 1565 worklist.push(old->fast_out(j)); 1566 1567 while( worklist.size() ) { // Visit all uses 1568 Node *use = worklist.pop(); 1569 if (!has_node(use)) continue; // Ignore dead nodes 1570 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); 1571 if( !loop->is_member( use_loop ) && use->is_CFG() ) { 1572 // Both OLD and USE are CFG nodes here. 1573 assert( use->is_Proj(), "" ); 1574 1575 // Clone the loop exit control projection 1576 Node *newuse = use->clone(); 1577 if (C->do_vector_loop()) { 1578 cm.verify_insert_and_clone(use, newuse, cm.clone_idx()); 1579 } 1580 newuse->set_req(0,nnn); 1581 _igvn.register_new_node_with_optimizer(newuse); 1582 set_loop(newuse, use_loop); 1583 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); 1584 1585 // We need a Region to merge the exit from the peeled body and the 1586 // exit from the old loop body. 1587 RegionNode *r = new RegionNode(3); 1588 // Map the old use to the new merge point 1589 old_new.map( use->_idx, r ); 1590 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); 1591 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); 1592 1593 // The original user of 'use' uses 'r' instead. 1594 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { 1595 Node* useuse = use->last_out(l); 1596 _igvn.rehash_node_delayed(useuse); 1597 uint uses_found = 0; 1598 if( useuse->in(0) == use ) { 1599 useuse->set_req(0, r); 1600 uses_found++; 1601 if( useuse->is_CFG() ) { 1602 assert( dom_depth(useuse) > dd_r, "" ); 1603 set_idom(useuse, r, dom_depth(useuse)); 1604 } 1605 } 1606 for( uint k = 1; k < useuse->req(); k++ ) { 1607 if( useuse->in(k) == use ) { 1608 useuse->set_req(k, r); 1609 uses_found++; 1610 } 1611 } 1612 l -= uses_found; // we deleted 1 or more copies of this edge 1613 } 1614 1615 // Now finish up 'r' 1616 r->set_req( 1, newuse ); 1617 r->set_req( 2, use ); 1618 _igvn.register_new_node_with_optimizer(r); 1619 set_loop(r, use_loop); 1620 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); 1621 } // End of if a loop-exit test 1622 } 1623 } 1624 1625 // Step 4: If loop-invariant use is not control, it must be dominated by a 1626 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region 1627 // there if needed. Make a Phi there merging old and new used values. 1628 Node_List *split_if_set = NULL; 1629 Node_List *split_bool_set = NULL; 1630 Node_List *split_cex_set = NULL; 1631 for( i = 0; i < loop->_body.size(); i++ ) { 1632 Node* old = loop->_body.at(i); 1633 Node* nnn = old_new[old->_idx]; 1634 // Copy uses to a worklist, so I can munge the def-use info 1635 // with impunity. 1636 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) 1637 worklist.push(old->fast_out(j)); 1638 1639 while( worklist.size() ) { 1640 Node *use = worklist.pop(); 1641 if (!has_node(use)) continue; // Ignore dead nodes 1642 if (use->in(0) == C->top()) continue; 1643 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); 1644 // Check for data-use outside of loop - at least one of OLD or USE 1645 // must not be a CFG node. 1646 if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { 1647 1648 // If the Data use is an IF, that means we have an IF outside of the 1649 // loop that is switching on a condition that is set inside of the 1650 // loop. Happens if people set a loop-exit flag; then test the flag 1651 // in the loop to break the loop, then test is again outside of the 1652 // loop to determine which way the loop exited. 1653 // Loop predicate If node connects to Bool node through Opaque1 node. 1654 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use)) { 1655 // Since this code is highly unlikely, we lazily build the worklist 1656 // of such Nodes to go split. 1657 if( !split_if_set ) 1658 split_if_set = new Node_List(area); 1659 split_if_set->push(use); 1660 } 1661 if( use->is_Bool() ) { 1662 if( !split_bool_set ) 1663 split_bool_set = new Node_List(area); 1664 split_bool_set->push(use); 1665 } 1666 if( use->Opcode() == Op_CreateEx ) { 1667 if( !split_cex_set ) 1668 split_cex_set = new Node_List(area); 1669 split_cex_set->push(use); 1670 } 1671 1672 1673 // Get "block" use is in 1674 uint idx = 0; 1675 while( use->in(idx) != old ) idx++; 1676 Node *prev = use->is_CFG() ? use : get_ctrl(use); 1677 assert( !loop->is_member( get_loop( prev ) ), "" ); 1678 Node *cfg = prev->_idx >= new_counter 1679 ? prev->in(2) 1680 : idom(prev); 1681 if( use->is_Phi() ) // Phi use is in prior block 1682 cfg = prev->in(idx); // NOT in block of Phi itself 1683 if (cfg->is_top()) { // Use is dead? 1684 _igvn.replace_input_of(use, idx, C->top()); 1685 continue; 1686 } 1687 1688 while( !loop->is_member( get_loop( cfg ) ) ) { 1689 prev = cfg; 1690 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); 1691 } 1692 // If the use occurs after merging several exits from the loop, then 1693 // old value must have dominated all those exits. Since the same old 1694 // value was used on all those exits we did not need a Phi at this 1695 // merge point. NOW we do need a Phi here. Each loop exit value 1696 // is now merged with the peeled body exit; each exit gets its own 1697 // private Phi and those Phis need to be merged here. 1698 Node *phi; 1699 if( prev->is_Region() ) { 1700 if( idx == 0 ) { // Updating control edge? 1701 phi = prev; // Just use existing control 1702 } else { // Else need a new Phi 1703 phi = PhiNode::make( prev, old ); 1704 // Now recursively fix up the new uses of old! 1705 for( uint i = 1; i < prev->req(); i++ ) { 1706 worklist.push(phi); // Onto worklist once for each 'old' input 1707 } 1708 } 1709 } else { 1710 // Get new RegionNode merging old and new loop exits 1711 prev = old_new[prev->_idx]; 1712 assert( prev, "just made this in step 7" ); 1713 if( idx == 0 ) { // Updating control edge? 1714 phi = prev; // Just use existing control 1715 } else { // Else need a new Phi 1716 // Make a new Phi merging data values properly 1717 phi = PhiNode::make( prev, old ); 1718 phi->set_req( 1, nnn ); 1719 } 1720 } 1721 // If inserting a new Phi, check for prior hits 1722 if( idx != 0 ) { 1723 Node *hit = _igvn.hash_find_insert(phi); 1724 if( hit == NULL ) { 1725 _igvn.register_new_node_with_optimizer(phi); // Register new phi 1726 } else { // or 1727 // Remove the new phi from the graph and use the hit 1728 _igvn.remove_dead_node(phi); 1729 phi = hit; // Use existing phi 1730 } 1731 set_ctrl(phi, prev); 1732 } 1733 // Make 'use' use the Phi instead of the old loop body exit value 1734 _igvn.replace_input_of(use, idx, phi); 1735 if( use->_idx >= new_counter ) { // If updating new phis 1736 // Not needed for correctness, but prevents a weak assert 1737 // in AddPNode from tripping (when we end up with different 1738 // base & derived Phis that will become the same after 1739 // IGVN does CSE). 1740 Node *hit = _igvn.hash_find_insert(use); 1741 if( hit ) // Go ahead and re-hash for hits. 1742 _igvn.replace_node( use, hit ); 1743 } 1744 1745 // If 'use' was in the loop-exit block, it now needs to be sunk 1746 // below the post-loop merge point. 1747 sink_use( use, prev ); 1748 } 1749 } 1750 } 1751 1752 // Check for IFs that need splitting/cloning. Happens if an IF outside of 1753 // the loop uses a condition set in the loop. The original IF probably 1754 // takes control from one or more OLD Regions (which in turn get from NEW 1755 // Regions). In any case, there will be a set of Phis for each merge point 1756 // from the IF up to where the original BOOL def exists the loop. 1757 if( split_if_set ) { 1758 while( split_if_set->size() ) { 1759 Node *iff = split_if_set->pop(); 1760 if( iff->in(1)->is_Phi() ) { 1761 BoolNode *b = clone_iff( iff->in(1)->as_Phi(), loop ); 1762 _igvn.replace_input_of(iff, 1, b); 1763 } 1764 } 1765 } 1766 if( split_bool_set ) { 1767 while( split_bool_set->size() ) { 1768 Node *b = split_bool_set->pop(); 1769 Node *phi = b->in(1); 1770 assert( phi->is_Phi(), "" ); 1771 CmpNode *cmp = clone_bool( (PhiNode*)phi, loop ); 1772 _igvn.replace_input_of(b, 1, cmp); 1773 } 1774 } 1775 if( split_cex_set ) { 1776 while( split_cex_set->size() ) { 1777 Node *b = split_cex_set->pop(); 1778 assert( b->in(0)->is_Region(), "" ); 1779 assert( b->in(1)->is_Phi(), "" ); 1780 assert( b->in(0)->in(0) == b->in(1)->in(0), "" ); 1781 split_up( b, b->in(0), NULL ); 1782 } 1783 } 1784 1785} 1786 1787 1788//---------------------- stride_of_possible_iv ------------------------------------- 1789// Looks for an iff/bool/comp with one operand of the compare 1790// being a cycle involving an add and a phi, 1791// with an optional truncation (left-shift followed by a right-shift) 1792// of the add. Returns zero if not an iv. 1793int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { 1794 Node* trunc1 = NULL; 1795 Node* trunc2 = NULL; 1796 const TypeInt* ttype = NULL; 1797 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { 1798 return 0; 1799 } 1800 BoolNode* bl = iff->in(1)->as_Bool(); 1801 Node* cmp = bl->in(1); 1802 if (!cmp || cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU) { 1803 return 0; 1804 } 1805 // Must have an invariant operand 1806 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { 1807 return 0; 1808 } 1809 Node* add2 = NULL; 1810 Node* cmp1 = cmp->in(1); 1811 if (cmp1->is_Phi()) { 1812 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) 1813 Node* phi = cmp1; 1814 for (uint i = 1; i < phi->req(); i++) { 1815 Node* in = phi->in(i); 1816 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, 1817 &trunc1, &trunc2, &ttype); 1818 if (add && add->in(1) == phi) { 1819 add2 = add->in(2); 1820 break; 1821 } 1822 } 1823 } else { 1824 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) 1825 Node* addtrunc = cmp1; 1826 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, 1827 &trunc1, &trunc2, &ttype); 1828 if (add && add->in(1)->is_Phi()) { 1829 Node* phi = add->in(1); 1830 for (uint i = 1; i < phi->req(); i++) { 1831 if (phi->in(i) == addtrunc) { 1832 add2 = add->in(2); 1833 break; 1834 } 1835 } 1836 } 1837 } 1838 if (add2 != NULL) { 1839 const TypeInt* add2t = _igvn.type(add2)->is_int(); 1840 if (add2t->is_con()) { 1841 return add2t->get_con(); 1842 } 1843 } 1844 return 0; 1845} 1846 1847 1848//---------------------- stay_in_loop ------------------------------------- 1849// Return the (unique) control output node that's in the loop (if it exists.) 1850Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { 1851 Node* unique = NULL; 1852 if (!n) return NULL; 1853 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1854 Node* use = n->fast_out(i); 1855 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { 1856 if (unique != NULL) { 1857 return NULL; 1858 } 1859 unique = use; 1860 } 1861 } 1862 return unique; 1863} 1864 1865//------------------------------ register_node ------------------------------------- 1866// Utility to register node "n" with PhaseIdealLoop 1867void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { 1868 _igvn.register_new_node_with_optimizer(n); 1869 loop->_body.push(n); 1870 if (n->is_CFG()) { 1871 set_loop(n, loop); 1872 set_idom(n, pred, ddepth); 1873 } else { 1874 set_ctrl(n, pred); 1875 } 1876} 1877 1878//------------------------------ proj_clone ------------------------------------- 1879// Utility to create an if-projection 1880ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { 1881 ProjNode* c = p->clone()->as_Proj(); 1882 c->set_req(0, iff); 1883 return c; 1884} 1885 1886//------------------------------ short_circuit_if ------------------------------------- 1887// Force the iff control output to be the live_proj 1888Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { 1889 guarantee(live_proj != NULL, "null projection"); 1890 int proj_con = live_proj->_con; 1891 assert(proj_con == 0 || proj_con == 1, "false or true projection"); 1892 Node *con = _igvn.intcon(proj_con); 1893 set_ctrl(con, C->root()); 1894 if (iff) { 1895 iff->set_req(1, con); 1896 } 1897 return con; 1898} 1899 1900//------------------------------ insert_if_before_proj ------------------------------------- 1901// Insert a new if before an if projection (* - new node) 1902// 1903// before 1904// if(test) 1905// / \ 1906// v v 1907// other-proj proj (arg) 1908// 1909// after 1910// if(test) 1911// / \ 1912// / v 1913// | * proj-clone 1914// v | 1915// other-proj v 1916// * new_if(relop(cmp[IU](left,right))) 1917// / \ 1918// v v 1919// * new-proj proj 1920// (returned) 1921// 1922ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { 1923 IfNode* iff = proj->in(0)->as_If(); 1924 IdealLoopTree *loop = get_loop(proj); 1925 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 1926 int ddepth = dom_depth(proj); 1927 1928 _igvn.rehash_node_delayed(iff); 1929 _igvn.rehash_node_delayed(proj); 1930 1931 proj->set_req(0, NULL); // temporary disconnect 1932 ProjNode* proj2 = proj_clone(proj, iff); 1933 register_node(proj2, loop, iff, ddepth); 1934 1935 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right); 1936 register_node(cmp, loop, proj2, ddepth); 1937 1938 BoolNode* bol = new BoolNode(cmp, relop); 1939 register_node(bol, loop, proj2, ddepth); 1940 1941 int opcode = iff->Opcode(); 1942 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode"); 1943 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt): 1944 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt); 1945 register_node(new_if, loop, proj2, ddepth); 1946 1947 proj->set_req(0, new_if); // reattach 1948 set_idom(proj, new_if, ddepth); 1949 1950 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); 1951 guarantee(new_exit != NULL, "null exit node"); 1952 register_node(new_exit, get_loop(other_proj), new_if, ddepth); 1953 1954 return new_exit; 1955} 1956 1957//------------------------------ insert_region_before_proj ------------------------------------- 1958// Insert a region before an if projection (* - new node) 1959// 1960// before 1961// if(test) 1962// / | 1963// v | 1964// proj v 1965// other-proj 1966// 1967// after 1968// if(test) 1969// / | 1970// v | 1971// * proj-clone v 1972// | other-proj 1973// v 1974// * new-region 1975// | 1976// v 1977// * dum_if 1978// / \ 1979// v \ 1980// * dum-proj v 1981// proj 1982// 1983RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { 1984 IfNode* iff = proj->in(0)->as_If(); 1985 IdealLoopTree *loop = get_loop(proj); 1986 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 1987 int ddepth = dom_depth(proj); 1988 1989 _igvn.rehash_node_delayed(iff); 1990 _igvn.rehash_node_delayed(proj); 1991 1992 proj->set_req(0, NULL); // temporary disconnect 1993 ProjNode* proj2 = proj_clone(proj, iff); 1994 register_node(proj2, loop, iff, ddepth); 1995 1996 RegionNode* reg = new RegionNode(2); 1997 reg->set_req(1, proj2); 1998 register_node(reg, loop, iff, ddepth); 1999 2000 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); 2001 register_node(dum_if, loop, reg, ddepth); 2002 2003 proj->set_req(0, dum_if); // reattach 2004 set_idom(proj, dum_if, ddepth); 2005 2006 ProjNode* dum_proj = proj_clone(other_proj, dum_if); 2007 register_node(dum_proj, loop, dum_if, ddepth); 2008 2009 return reg; 2010} 2011 2012//------------------------------ insert_cmpi_loop_exit ------------------------------------- 2013// Clone a signed compare loop exit from an unsigned compare and 2014// insert it before the unsigned cmp on the stay-in-loop path. 2015// All new nodes inserted in the dominator tree between the original 2016// if and it's projections. The original if test is replaced with 2017// a constant to force the stay-in-loop path. 2018// 2019// This is done to make sure that the original if and it's projections 2020// still dominate the same set of control nodes, that the ctrl() relation 2021// from data nodes to them is preserved, and that their loop nesting is 2022// preserved. 2023// 2024// before 2025// if(i <u limit) unsigned compare loop exit 2026// / | 2027// v v 2028// exit-proj stay-in-loop-proj 2029// 2030// after 2031// if(stay-in-loop-const) original if 2032// / | 2033// / v 2034// / if(i < limit) new signed test 2035// / / | 2036// / / v 2037// / / if(i <u limit) new cloned unsigned test 2038// / / / | 2039// v v v | 2040// region | 2041// | | 2042// dum-if | 2043// / | | 2044// ether | | 2045// v v 2046// exit-proj stay-in-loop-proj 2047// 2048IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { 2049 const bool Signed = true; 2050 const bool Unsigned = false; 2051 2052 BoolNode* bol = if_cmpu->in(1)->as_Bool(); 2053 if (bol->_test._test != BoolTest::lt) return NULL; 2054 CmpNode* cmpu = bol->in(1)->as_Cmp(); 2055 if (cmpu->Opcode() != Op_CmpU) return NULL; 2056 int stride = stride_of_possible_iv(if_cmpu); 2057 if (stride == 0) return NULL; 2058 2059 Node* lp_proj = stay_in_loop(if_cmpu, loop); 2060 guarantee(lp_proj != NULL, "null loop node"); 2061 2062 ProjNode* lp_continue = lp_proj->as_Proj(); 2063 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); 2064 2065 Node* limit = NULL; 2066 if (stride > 0) { 2067 limit = cmpu->in(2); 2068 } else { 2069 limit = _igvn.makecon(TypeInt::ZERO); 2070 set_ctrl(limit, C->root()); 2071 } 2072 // Create a new region on the exit path 2073 RegionNode* reg = insert_region_before_proj(lp_exit); 2074 guarantee(reg != NULL, "null region node"); 2075 2076 // Clone the if-cmpu-true-false using a signed compare 2077 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; 2078 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); 2079 reg->add_req(cmpi_exit); 2080 2081 // Clone the if-cmpu-true-false 2082 BoolTest::mask rel_u = bol->_test._test; 2083 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); 2084 reg->add_req(cmpu_exit); 2085 2086 // Force original if to stay in loop. 2087 short_circuit_if(if_cmpu, lp_continue); 2088 2089 return cmpi_exit->in(0)->as_If(); 2090} 2091 2092//------------------------------ remove_cmpi_loop_exit ------------------------------------- 2093// Remove a previously inserted signed compare loop exit. 2094void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { 2095 Node* lp_proj = stay_in_loop(if_cmp, loop); 2096 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && 2097 stay_in_loop(lp_proj, loop)->is_If() && 2098 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); 2099 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); 2100 set_ctrl(con, C->root()); 2101 if_cmp->set_req(1, con); 2102} 2103 2104//------------------------------ scheduled_nodelist ------------------------------------- 2105// Create a post order schedule of nodes that are in the 2106// "member" set. The list is returned in "sched". 2107// The first node in "sched" is the loop head, followed by 2108// nodes which have no inputs in the "member" set, and then 2109// followed by the nodes that have an immediate input dependence 2110// on a node in "sched". 2111void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { 2112 2113 assert(member.test(loop->_head->_idx), "loop head must be in member set"); 2114 Arena *a = Thread::current()->resource_area(); 2115 VectorSet visited(a); 2116 Node_Stack nstack(a, loop->_body.size()); 2117 2118 Node* n = loop->_head; // top of stack is cached in "n" 2119 uint idx = 0; 2120 visited.set(n->_idx); 2121 2122 // Initially push all with no inputs from within member set 2123 for(uint i = 0; i < loop->_body.size(); i++ ) { 2124 Node *elt = loop->_body.at(i); 2125 if (member.test(elt->_idx)) { 2126 bool found = false; 2127 for (uint j = 0; j < elt->req(); j++) { 2128 Node* def = elt->in(j); 2129 if (def && member.test(def->_idx) && def != elt) { 2130 found = true; 2131 break; 2132 } 2133 } 2134 if (!found && elt != loop->_head) { 2135 nstack.push(n, idx); 2136 n = elt; 2137 assert(!visited.test(n->_idx), "not seen yet"); 2138 visited.set(n->_idx); 2139 } 2140 } 2141 } 2142 2143 // traverse out's that are in the member set 2144 while (true) { 2145 if (idx < n->outcnt()) { 2146 Node* use = n->raw_out(idx); 2147 idx++; 2148 if (!visited.test_set(use->_idx)) { 2149 if (member.test(use->_idx)) { 2150 nstack.push(n, idx); 2151 n = use; 2152 idx = 0; 2153 } 2154 } 2155 } else { 2156 // All outputs processed 2157 sched.push(n); 2158 if (nstack.is_empty()) break; 2159 n = nstack.node(); 2160 idx = nstack.index(); 2161 nstack.pop(); 2162 } 2163 } 2164} 2165 2166 2167//------------------------------ has_use_in_set ------------------------------------- 2168// Has a use in the vector set 2169bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { 2170 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2171 Node* use = n->fast_out(j); 2172 if (vset.test(use->_idx)) { 2173 return true; 2174 } 2175 } 2176 return false; 2177} 2178 2179 2180//------------------------------ has_use_internal_to_set ------------------------------------- 2181// Has use internal to the vector set (ie. not in a phi at the loop head) 2182bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { 2183 Node* head = loop->_head; 2184 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2185 Node* use = n->fast_out(j); 2186 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { 2187 return true; 2188 } 2189 } 2190 return false; 2191} 2192 2193 2194//------------------------------ clone_for_use_outside_loop ------------------------------------- 2195// clone "n" for uses that are outside of loop 2196int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { 2197 int cloned = 0; 2198 assert(worklist.size() == 0, "should be empty"); 2199 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2200 Node* use = n->fast_out(j); 2201 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { 2202 worklist.push(use); 2203 } 2204 } 2205 while( worklist.size() ) { 2206 Node *use = worklist.pop(); 2207 if (!has_node(use) || use->in(0) == C->top()) continue; 2208 uint j; 2209 for (j = 0; j < use->req(); j++) { 2210 if (use->in(j) == n) break; 2211 } 2212 assert(j < use->req(), "must be there"); 2213 2214 // clone "n" and insert it between the inputs of "n" and the use outside the loop 2215 Node* n_clone = n->clone(); 2216 _igvn.replace_input_of(use, j, n_clone); 2217 cloned++; 2218 Node* use_c; 2219 if (!use->is_Phi()) { 2220 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); 2221 } else { 2222 // Use in a phi is considered a use in the associated predecessor block 2223 use_c = use->in(0)->in(j); 2224 } 2225 set_ctrl(n_clone, use_c); 2226 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); 2227 get_loop(use_c)->_body.push(n_clone); 2228 _igvn.register_new_node_with_optimizer(n_clone); 2229#if !defined(PRODUCT) 2230 if (TracePartialPeeling) { 2231 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); 2232 } 2233#endif 2234 } 2235 return cloned; 2236} 2237 2238 2239//------------------------------ clone_for_special_use_inside_loop ------------------------------------- 2240// clone "n" for special uses that are in the not_peeled region. 2241// If these def-uses occur in separate blocks, the code generator 2242// marks the method as not compilable. For example, if a "BoolNode" 2243// is in a different basic block than the "IfNode" that uses it, then 2244// the compilation is aborted in the code generator. 2245void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, 2246 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { 2247 if (n->is_Phi() || n->is_Load()) { 2248 return; 2249 } 2250 assert(worklist.size() == 0, "should be empty"); 2251 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2252 Node* use = n->fast_out(j); 2253 if ( not_peel.test(use->_idx) && 2254 (use->is_If() || use->is_CMove() || use->is_Bool()) && 2255 use->in(1) == n) { 2256 worklist.push(use); 2257 } 2258 } 2259 if (worklist.size() > 0) { 2260 // clone "n" and insert it between inputs of "n" and the use 2261 Node* n_clone = n->clone(); 2262 loop->_body.push(n_clone); 2263 _igvn.register_new_node_with_optimizer(n_clone); 2264 set_ctrl(n_clone, get_ctrl(n)); 2265 sink_list.push(n_clone); 2266 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. 2267#if !defined(PRODUCT) 2268 if (TracePartialPeeling) { 2269 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); 2270 } 2271#endif 2272 while( worklist.size() ) { 2273 Node *use = worklist.pop(); 2274 _igvn.rehash_node_delayed(use); 2275 for (uint j = 1; j < use->req(); j++) { 2276 if (use->in(j) == n) { 2277 use->set_req(j, n_clone); 2278 } 2279 } 2280 } 2281 } 2282} 2283 2284 2285//------------------------------ insert_phi_for_loop ------------------------------------- 2286// Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist 2287void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { 2288 Node *phi = PhiNode::make(lp, back_edge_val); 2289 phi->set_req(LoopNode::EntryControl, lp_entry_val); 2290 // Use existing phi if it already exists 2291 Node *hit = _igvn.hash_find_insert(phi); 2292 if( hit == NULL ) { 2293 _igvn.register_new_node_with_optimizer(phi); 2294 set_ctrl(phi, lp); 2295 } else { 2296 // Remove the new phi from the graph and use the hit 2297 _igvn.remove_dead_node(phi); 2298 phi = hit; 2299 } 2300 _igvn.replace_input_of(use, idx, phi); 2301} 2302 2303#ifdef ASSERT 2304//------------------------------ is_valid_loop_partition ------------------------------------- 2305// Validate the loop partition sets: peel and not_peel 2306bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, 2307 VectorSet& not_peel ) { 2308 uint i; 2309 // Check that peel_list entries are in the peel set 2310 for (i = 0; i < peel_list.size(); i++) { 2311 if (!peel.test(peel_list.at(i)->_idx)) { 2312 return false; 2313 } 2314 } 2315 // Check at loop members are in one of peel set or not_peel set 2316 for (i = 0; i < loop->_body.size(); i++ ) { 2317 Node *def = loop->_body.at(i); 2318 uint di = def->_idx; 2319 // Check that peel set elements are in peel_list 2320 if (peel.test(di)) { 2321 if (not_peel.test(di)) { 2322 return false; 2323 } 2324 // Must be in peel_list also 2325 bool found = false; 2326 for (uint j = 0; j < peel_list.size(); j++) { 2327 if (peel_list.at(j)->_idx == di) { 2328 found = true; 2329 break; 2330 } 2331 } 2332 if (!found) { 2333 return false; 2334 } 2335 } else if (not_peel.test(di)) { 2336 if (peel.test(di)) { 2337 return false; 2338 } 2339 } else { 2340 return false; 2341 } 2342 } 2343 return true; 2344} 2345 2346//------------------------------ is_valid_clone_loop_exit_use ------------------------------------- 2347// Ensure a use outside of loop is of the right form 2348bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { 2349 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 2350 return (use->is_Phi() && 2351 use_c->is_Region() && use_c->req() == 3 && 2352 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || 2353 use_c->in(exit_idx)->Opcode() == Op_IfFalse || 2354 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && 2355 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); 2356} 2357 2358//------------------------------ is_valid_clone_loop_form ------------------------------------- 2359// Ensure that all uses outside of loop are of the right form 2360bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, 2361 uint orig_exit_idx, uint clone_exit_idx) { 2362 uint len = peel_list.size(); 2363 for (uint i = 0; i < len; i++) { 2364 Node *def = peel_list.at(i); 2365 2366 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 2367 Node *use = def->fast_out(j); 2368 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 2369 if (!loop->is_member(get_loop(use_c))) { 2370 // use is not in the loop, check for correct structure 2371 if (use->in(0) == def) { 2372 // Okay 2373 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { 2374 return false; 2375 } 2376 } 2377 } 2378 } 2379 return true; 2380} 2381#endif 2382 2383//------------------------------ partial_peel ------------------------------------- 2384// Partially peel (aka loop rotation) the top portion of a loop (called 2385// the peel section below) by cloning it and placing one copy just before 2386// the new loop head and the other copy at the bottom of the new loop. 2387// 2388// before after where it came from 2389// 2390// stmt1 stmt1 2391// loop: stmt2 clone 2392// stmt2 if condA goto exitA clone 2393// if condA goto exitA new_loop: new 2394// stmt3 stmt3 clone 2395// if !condB goto loop if condB goto exitB clone 2396// exitB: stmt2 orig 2397// stmt4 if !condA goto new_loop orig 2398// exitA: goto exitA 2399// exitB: 2400// stmt4 2401// exitA: 2402// 2403// Step 1: find the cut point: an exit test on probable 2404// induction variable. 2405// Step 2: schedule (with cloning) operations in the peel 2406// section that can be executed after the cut into 2407// the section that is not peeled. This may need 2408// to clone operations into exit blocks. For 2409// instance, a reference to A[i] in the not-peel 2410// section and a reference to B[i] in an exit block 2411// may cause a left-shift of i by 2 to be placed 2412// in the peel block. This step will clone the left 2413// shift into the exit block and sink the left shift 2414// from the peel to the not-peel section. 2415// Step 3: clone the loop, retarget the control, and insert 2416// phis for values that are live across the new loop 2417// head. This is very dependent on the graph structure 2418// from clone_loop. It creates region nodes for 2419// exit control and associated phi nodes for values 2420// flow out of the loop through that exit. The region 2421// node is dominated by the clone's control projection. 2422// So the clone's peel section is placed before the 2423// new loop head, and the clone's not-peel section is 2424// forms the top part of the new loop. The original 2425// peel section forms the tail of the new loop. 2426// Step 4: update the dominator tree and recompute the 2427// dominator depth. 2428// 2429// orig 2430// 2431// stmt1 2432// | 2433// v 2434// loop predicate 2435// | 2436// v 2437// loop<----+ 2438// | | 2439// stmt2 | 2440// | | 2441// v | 2442// ifA | 2443// / | | 2444// v v | 2445// false true ^ <-- last_peel 2446// / | | 2447// / ===|==cut | 2448// / stmt3 | <-- first_not_peel 2449// / | | 2450// | v | 2451// v ifB | 2452// exitA: / \ | 2453// / \ | 2454// v v | 2455// false true | 2456// / \ | 2457// / ----+ 2458// | 2459// v 2460// exitB: 2461// stmt4 2462// 2463// 2464// after clone loop 2465// 2466// stmt1 2467// | 2468// v 2469// loop predicate 2470// / \ 2471// clone / \ orig 2472// / \ 2473// / \ 2474// v v 2475// +---->loop loop<----+ 2476// | | | | 2477// | stmt2 stmt2 | 2478// | | | | 2479// | v v | 2480// | ifA ifA | 2481// | | \ / | | 2482// | v v v v | 2483// ^ true false false true ^ <-- last_peel 2484// | | ^ \ / | | 2485// | cut==|== \ \ / ===|==cut | 2486// | stmt3 \ \ / stmt3 | <-- first_not_peel 2487// | | dom | | | | 2488// | v \ 1v v2 v | 2489// | ifB regionA ifB | 2490// | / \ | / \ | 2491// | / \ v / \ | 2492// | v v exitA: v v | 2493// | true false false true | 2494// | / ^ \ / \ | 2495// +---- \ \ / ----+ 2496// dom \ / 2497// \ 1v v2 2498// regionB 2499// | 2500// v 2501// exitB: 2502// stmt4 2503// 2504// 2505// after partial peel 2506// 2507// stmt1 2508// | 2509// v 2510// loop predicate 2511// / 2512// clone / orig 2513// / TOP 2514// / \ 2515// v v 2516// TOP->loop loop----+ 2517// | | | 2518// stmt2 stmt2 | 2519// | | | 2520// v v | 2521// ifA ifA | 2522// | \ / | | 2523// v v v v | 2524// true false false true | <-- last_peel 2525// | ^ \ / +------|---+ 2526// +->newloop \ \ / === ==cut | | 2527// | stmt3 \ \ / TOP | | 2528// | | dom | | stmt3 | | <-- first_not_peel 2529// | v \ 1v v2 v | | 2530// | ifB regionA ifB ^ v 2531// | / \ | / \ | | 2532// | / \ v / \ | | 2533// | v v exitA: v v | | 2534// | true false false true | | 2535// | / ^ \ / \ | | 2536// | | \ \ / v | | 2537// | | dom \ / TOP | | 2538// | | \ 1v v2 | | 2539// ^ v regionB | | 2540// | | | | | 2541// | | v ^ v 2542// | | exitB: | | 2543// | | stmt4 | | 2544// | +------------>-----------------+ | 2545// | | 2546// +-----------------<---------------------+ 2547// 2548// 2549// final graph 2550// 2551// stmt1 2552// | 2553// v 2554// loop predicate 2555// | 2556// v 2557// stmt2 clone 2558// | 2559// v 2560// ........> ifA clone 2561// : / | 2562// dom / | 2563// : v v 2564// : false true 2565// : | | 2566// : | v 2567// : | newloop<-----+ 2568// : | | | 2569// : | stmt3 clone | 2570// : | | | 2571// : | v | 2572// : | ifB | 2573// : | / \ | 2574// : | v v | 2575// : | false true | 2576// : | | | | 2577// : | v stmt2 | 2578// : | exitB: | | 2579// : | stmt4 v | 2580// : | ifA orig | 2581// : | / \ | 2582// : | / \ | 2583// : | v v | 2584// : | false true | 2585// : | / \ | 2586// : v v -----+ 2587// RegionA 2588// | 2589// v 2590// exitA 2591// 2592bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { 2593 2594 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only"); 2595 if (!loop->_head->is_Loop()) { 2596 return false; } 2597 2598 LoopNode *head = loop->_head->as_Loop(); 2599 2600 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { 2601 return false; 2602 } 2603 2604 // Check for complex exit control 2605 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { 2606 Node *n = loop->_body.at(ii); 2607 int opc = n->Opcode(); 2608 if (n->is_Call() || 2609 opc == Op_Catch || 2610 opc == Op_CatchProj || 2611 opc == Op_Jump || 2612 opc == Op_JumpProj) { 2613#if !defined(PRODUCT) 2614 if (TracePartialPeeling) { 2615 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); 2616 } 2617#endif 2618 return false; 2619 } 2620 } 2621 2622 int dd = dom_depth(head); 2623 2624 // Step 1: find cut point 2625 2626 // Walk up dominators to loop head looking for first loop exit 2627 // which is executed on every path thru loop. 2628 IfNode *peel_if = NULL; 2629 IfNode *peel_if_cmpu = NULL; 2630 2631 Node *iff = loop->tail(); 2632 while( iff != head ) { 2633 if( iff->is_If() ) { 2634 Node *ctrl = get_ctrl(iff->in(1)); 2635 if (ctrl->is_top()) return false; // Dead test on live IF. 2636 // If loop-varying exit-test, check for induction variable 2637 if( loop->is_member(get_loop(ctrl)) && 2638 loop->is_loop_exit(iff) && 2639 is_possible_iv_test(iff)) { 2640 Node* cmp = iff->in(1)->in(1); 2641 if (cmp->Opcode() == Op_CmpI) { 2642 peel_if = iff->as_If(); 2643 } else { 2644 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); 2645 peel_if_cmpu = iff->as_If(); 2646 } 2647 } 2648 } 2649 iff = idom(iff); 2650 } 2651 // Prefer signed compare over unsigned compare. 2652 IfNode* new_peel_if = NULL; 2653 if (peel_if == NULL) { 2654 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { 2655 return false; // No peel point found 2656 } 2657 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); 2658 if (new_peel_if == NULL) { 2659 return false; // No peel point found 2660 } 2661 peel_if = new_peel_if; 2662 } 2663 Node* last_peel = stay_in_loop(peel_if, loop); 2664 Node* first_not_peeled = stay_in_loop(last_peel, loop); 2665 if (first_not_peeled == NULL || first_not_peeled == head) { 2666 return false; 2667 } 2668 2669#if !defined(PRODUCT) 2670 if (TraceLoopOpts) { 2671 tty->print("PartialPeel "); 2672 loop->dump_head(); 2673 } 2674 2675 if (TracePartialPeeling) { 2676 tty->print_cr("before partial peel one iteration"); 2677 Node_List wl; 2678 Node* t = head->in(2); 2679 while (true) { 2680 wl.push(t); 2681 if (t == head) break; 2682 t = idom(t); 2683 } 2684 while (wl.size() > 0) { 2685 Node* tt = wl.pop(); 2686 tt->dump(); 2687 if (tt == last_peel) tty->print_cr("-- cut --"); 2688 } 2689 } 2690#endif 2691 ResourceArea *area = Thread::current()->resource_area(); 2692 VectorSet peel(area); 2693 VectorSet not_peel(area); 2694 Node_List peel_list(area); 2695 Node_List worklist(area); 2696 Node_List sink_list(area); 2697 2698 // Set of cfg nodes to peel are those that are executable from 2699 // the head through last_peel. 2700 assert(worklist.size() == 0, "should be empty"); 2701 worklist.push(head); 2702 peel.set(head->_idx); 2703 while (worklist.size() > 0) { 2704 Node *n = worklist.pop(); 2705 if (n != last_peel) { 2706 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2707 Node* use = n->fast_out(j); 2708 if (use->is_CFG() && 2709 loop->is_member(get_loop(use)) && 2710 !peel.test_set(use->_idx)) { 2711 worklist.push(use); 2712 } 2713 } 2714 } 2715 } 2716 2717 // Set of non-cfg nodes to peel are those that are control 2718 // dependent on the cfg nodes. 2719 uint i; 2720 for(i = 0; i < loop->_body.size(); i++ ) { 2721 Node *n = loop->_body.at(i); 2722 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; 2723 if (peel.test(n_c->_idx)) { 2724 peel.set(n->_idx); 2725 } else { 2726 not_peel.set(n->_idx); 2727 } 2728 } 2729 2730 // Step 2: move operations from the peeled section down into the 2731 // not-peeled section 2732 2733 // Get a post order schedule of nodes in the peel region 2734 // Result in right-most operand. 2735 scheduled_nodelist(loop, peel, peel_list ); 2736 2737 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 2738 2739 // For future check for too many new phis 2740 uint old_phi_cnt = 0; 2741 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { 2742 Node* use = head->fast_out(j); 2743 if (use->is_Phi()) old_phi_cnt++; 2744 } 2745 2746#if !defined(PRODUCT) 2747 if (TracePartialPeeling) { 2748 tty->print_cr("\npeeled list"); 2749 } 2750#endif 2751 2752 // Evacuate nodes in peel region into the not_peeled region if possible 2753 uint new_phi_cnt = 0; 2754 uint cloned_for_outside_use = 0; 2755 for (i = 0; i < peel_list.size();) { 2756 Node* n = peel_list.at(i); 2757#if !defined(PRODUCT) 2758 if (TracePartialPeeling) n->dump(); 2759#endif 2760 bool incr = true; 2761 if ( !n->is_CFG() ) { 2762 2763 if ( has_use_in_set(n, not_peel) ) { 2764 2765 // If not used internal to the peeled region, 2766 // move "n" from peeled to not_peeled region. 2767 2768 if ( !has_use_internal_to_set(n, peel, loop) ) { 2769 2770 // if not pinned and not a load (which maybe anti-dependent on a store) 2771 // and not a CMove (Matcher expects only bool->cmove). 2772 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { 2773 cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist ); 2774 sink_list.push(n); 2775 peel >>= n->_idx; // delete n from peel set. 2776 not_peel <<= n->_idx; // add n to not_peel set. 2777 peel_list.remove(i); 2778 incr = false; 2779#if !defined(PRODUCT) 2780 if (TracePartialPeeling) { 2781 tty->print_cr("sink to not_peeled region: %d newbb: %d", 2782 n->_idx, get_ctrl(n)->_idx); 2783 } 2784#endif 2785 } 2786 } else { 2787 // Otherwise check for special def-use cases that span 2788 // the peel/not_peel boundary such as bool->if 2789 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); 2790 new_phi_cnt++; 2791 } 2792 } 2793 } 2794 if (incr) i++; 2795 } 2796 2797 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { 2798#if !defined(PRODUCT) 2799 if (TracePartialPeeling) { 2800 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", 2801 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); 2802 } 2803#endif 2804 if (new_peel_if != NULL) { 2805 remove_cmpi_loop_exit(new_peel_if, loop); 2806 } 2807 // Inhibit more partial peeling on this loop 2808 assert(!head->is_partial_peel_loop(), "not partial peeled"); 2809 head->mark_partial_peel_failed(); 2810 if (cloned_for_outside_use > 0) { 2811 // Terminate this round of loop opts because 2812 // the graph outside this loop was changed. 2813 C->set_major_progress(); 2814 return true; 2815 } 2816 return false; 2817 } 2818 2819 // Step 3: clone loop, retarget control, and insert new phis 2820 2821 // Create new loop head for new phis and to hang 2822 // the nodes being moved (sinked) from the peel region. 2823 LoopNode* new_head = new LoopNode(last_peel, last_peel); 2824 new_head->set_unswitch_count(head->unswitch_count()); // Preserve 2825 _igvn.register_new_node_with_optimizer(new_head); 2826 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); 2827 _igvn.replace_input_of(first_not_peeled, 0, new_head); 2828 set_loop(new_head, loop); 2829 loop->_body.push(new_head); 2830 not_peel.set(new_head->_idx); 2831 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); 2832 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); 2833 2834 while (sink_list.size() > 0) { 2835 Node* n = sink_list.pop(); 2836 set_ctrl(n, new_head); 2837 } 2838 2839 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 2840 2841 clone_loop( loop, old_new, dd ); 2842 2843 const uint clone_exit_idx = 1; 2844 const uint orig_exit_idx = 2; 2845 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); 2846 2847 Node* head_clone = old_new[head->_idx]; 2848 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); 2849 Node* orig_tail_clone = head_clone->in(2); 2850 2851 // Add phi if "def" node is in peel set and "use" is not 2852 2853 for(i = 0; i < peel_list.size(); i++ ) { 2854 Node *def = peel_list.at(i); 2855 if (!def->is_CFG()) { 2856 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 2857 Node *use = def->fast_out(j); 2858 if (has_node(use) && use->in(0) != C->top() && 2859 (!peel.test(use->_idx) || 2860 (use->is_Phi() && use->in(0) == head)) ) { 2861 worklist.push(use); 2862 } 2863 } 2864 while( worklist.size() ) { 2865 Node *use = worklist.pop(); 2866 for (uint j = 1; j < use->req(); j++) { 2867 Node* n = use->in(j); 2868 if (n == def) { 2869 2870 // "def" is in peel set, "use" is not in peel set 2871 // or "use" is in the entry boundary (a phi) of the peel set 2872 2873 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; 2874 2875 if ( loop->is_member(get_loop( use_c )) ) { 2876 // use is in loop 2877 if (old_new[use->_idx] != NULL) { // null for dead code 2878 Node* use_clone = old_new[use->_idx]; 2879 _igvn.replace_input_of(use, j, C->top()); 2880 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); 2881 } 2882 } else { 2883 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); 2884 // use is not in the loop, check if the live range includes the cut 2885 Node* lp_if = use_c->in(orig_exit_idx)->in(0); 2886 if (not_peel.test(lp_if->_idx)) { 2887 assert(j == orig_exit_idx, "use from original loop"); 2888 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); 2889 } 2890 } 2891 } 2892 } 2893 } 2894 } 2895 } 2896 2897 // Step 3b: retarget control 2898 2899 // Redirect control to the new loop head if a cloned node in 2900 // the not_peeled region has control that points into the peeled region. 2901 // This necessary because the cloned peeled region will be outside 2902 // the loop. 2903 // from to 2904 // cloned-peeled <---+ 2905 // new_head_clone: | <--+ 2906 // cloned-not_peeled in(0) in(0) 2907 // orig-peeled 2908 2909 for(i = 0; i < loop->_body.size(); i++ ) { 2910 Node *n = loop->_body.at(i); 2911 if (!n->is_CFG() && n->in(0) != NULL && 2912 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { 2913 Node* n_clone = old_new[n->_idx]; 2914 _igvn.replace_input_of(n_clone, 0, new_head_clone); 2915 } 2916 } 2917 2918 // Backedge of the surviving new_head (the clone) is original last_peel 2919 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel); 2920 2921 // Cut first node in original not_peel set 2922 _igvn.rehash_node_delayed(new_head); // Multiple edge updates: 2923 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of 2924 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls 2925 2926 // Copy head_clone back-branch info to original head 2927 // and remove original head's loop entry and 2928 // clone head's back-branch 2929 _igvn.rehash_node_delayed(head); // Multiple edge updates 2930 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); 2931 head->set_req(LoopNode::LoopBackControl, C->top()); 2932 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top()); 2933 2934 // Similarly modify the phis 2935 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { 2936 Node* use = head->fast_out(k); 2937 if (use->is_Phi() && use->outcnt() > 0) { 2938 Node* use_clone = old_new[use->_idx]; 2939 _igvn.rehash_node_delayed(use); // Multiple edge updates 2940 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); 2941 use->set_req(LoopNode::LoopBackControl, C->top()); 2942 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top()); 2943 } 2944 } 2945 2946 // Step 4: update dominator tree and dominator depth 2947 2948 set_idom(head, orig_tail_clone, dd); 2949 recompute_dom_depth(); 2950 2951 // Inhibit more partial peeling on this loop 2952 new_head_clone->set_partial_peel_loop(); 2953 C->set_major_progress(); 2954 loop->record_for_igvn(); 2955 2956#if !defined(PRODUCT) 2957 if (TracePartialPeeling) { 2958 tty->print_cr("\nafter partial peel one iteration"); 2959 Node_List wl(area); 2960 Node* t = last_peel; 2961 while (true) { 2962 wl.push(t); 2963 if (t == head_clone) break; 2964 t = idom(t); 2965 } 2966 while (wl.size() > 0) { 2967 Node* tt = wl.pop(); 2968 if (tt == head) tty->print_cr("orig head"); 2969 else if (tt == new_head_clone) tty->print_cr("new head"); 2970 else if (tt == head_clone) tty->print_cr("clone head"); 2971 tt->dump(); 2972 } 2973 } 2974#endif 2975 return true; 2976} 2977 2978//------------------------------reorg_offsets---------------------------------- 2979// Reorganize offset computations to lower register pressure. Mostly 2980// prevent loop-fallout uses of the pre-incremented trip counter (which are 2981// then alive with the post-incremented trip counter forcing an extra 2982// register move) 2983void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) { 2984 // Perform it only for canonical counted loops. 2985 // Loop's shape could be messed up by iteration_split_impl. 2986 if (!loop->_head->is_CountedLoop()) 2987 return; 2988 if (!loop->_head->as_Loop()->is_valid_counted_loop()) 2989 return; 2990 2991 CountedLoopNode *cl = loop->_head->as_CountedLoop(); 2992 CountedLoopEndNode *cle = cl->loopexit(); 2993 Node *exit = cle->proj_out(false); 2994 Node *phi = cl->phi(); 2995 2996 // Check for the special case of folks using the pre-incremented 2997 // trip-counter on the fall-out path (forces the pre-incremented 2998 // and post-incremented trip counter to be live at the same time). 2999 // Fix this by adjusting to use the post-increment trip counter. 3000 3001 bool progress = true; 3002 while (progress) { 3003 progress = false; 3004 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { 3005 Node* use = phi->fast_out(i); // User of trip-counter 3006 if (!has_ctrl(use)) continue; 3007 Node *u_ctrl = get_ctrl(use); 3008 if (use->is_Phi()) { 3009 u_ctrl = NULL; 3010 for (uint j = 1; j < use->req(); j++) 3011 if (use->in(j) == phi) 3012 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j)); 3013 } 3014 IdealLoopTree *u_loop = get_loop(u_ctrl); 3015 // Look for loop-invariant use 3016 if (u_loop == loop) continue; 3017 if (loop->is_member(u_loop)) continue; 3018 // Check that use is live out the bottom. Assuming the trip-counter 3019 // update is right at the bottom, uses of of the loop middle are ok. 3020 if (dom_lca(exit, u_ctrl) != exit) continue; 3021 // Hit! Refactor use to use the post-incremented tripcounter. 3022 // Compute a post-increment tripcounter. 3023 Node *opaq = new Opaque2Node( C, cle->incr() ); 3024 register_new_node(opaq, exit); 3025 Node *neg_stride = _igvn.intcon(-cle->stride_con()); 3026 set_ctrl(neg_stride, C->root()); 3027 Node *post = new AddINode( opaq, neg_stride); 3028 register_new_node(post, exit); 3029 _igvn.rehash_node_delayed(use); 3030 for (uint j = 1; j < use->req(); j++) { 3031 if (use->in(j) == phi) 3032 use->set_req(j, post); 3033 } 3034 // Since DU info changed, rerun loop 3035 progress = true; 3036 break; 3037 } 3038 } 3039 3040} 3041