1 /* 2 * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "memory/allocation.inline.hpp" 27 #include "memory/resourceArea.hpp" 28 #include "opto/addnode.hpp" 29 #include "opto/callnode.hpp" 30 #include "opto/castnode.hpp" 31 #include "opto/connode.hpp" 32 #include "opto/castnode.hpp" 33 #include "opto/divnode.hpp" 34 #include "opto/loopnode.hpp" 35 #include "opto/matcher.hpp" 36 #include "opto/mulnode.hpp" 37 #include "opto/movenode.hpp" 38 #include "opto/opaquenode.hpp" 39 #include "opto/rootnode.hpp" 40 #include "opto/subnode.hpp" 41 42 //============================================================================= 43 //------------------------------split_thru_phi--------------------------------- 44 // Split Node 'n' through merge point if there is enough win. 45 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { 46 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { 47 // ConvI2L may have type information on it which is unsafe to push up 48 // so disable this for now 49 return NULL; 50 } 51 52 // Splitting range check CastIIs through a loop induction Phi can 53 // cause new Phis to be created that are left unrelated to the loop 54 // induction Phi and prevent optimizations (vectorization) 55 if (n->Opcode() == Op_CastII && n->as_CastII()->has_range_check() && 56 region->is_CountedLoop() && n->in(1) == region->as_CountedLoop()->phi()) { 57 return NULL; 58 } 59 60 int wins = 0; 61 assert(!n->is_CFG(), ""); 62 assert(region->is_Region(), ""); 63 64 const Type* type = n->bottom_type(); 65 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); 66 Node *phi; 67 if (t_oop != NULL && t_oop->is_known_instance_field()) { 68 int iid = t_oop->instance_id(); 69 int index = C->get_alias_index(t_oop); 70 int offset = t_oop->offset(); 71 phi = new PhiNode(region, type, NULL, iid, index, offset); 72 } else { 73 phi = PhiNode::make_blank(region, n); 74 } 75 uint old_unique = C->unique(); 76 for (uint i = 1; i < region->req(); i++) { 77 Node *x; 78 Node* the_clone = NULL; 79 if (region->in(i) == C->top()) { 80 x = C->top(); // Dead path? Use a dead data op 81 } else { 82 x = n->clone(); // Else clone up the data op 83 the_clone = x; // Remember for possible deletion. 84 // Alter data node to use pre-phi inputs 85 if (n->in(0) == region) 86 x->set_req( 0, region->in(i) ); 87 for (uint j = 1; j < n->req(); j++) { 88 Node *in = n->in(j); 89 if (in->is_Phi() && in->in(0) == region) 90 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone 91 } 92 } 93 // Check for a 'win' on some paths 94 const Type *t = x->Value(&_igvn); 95 96 bool singleton = t->singleton(); 97 98 // A TOP singleton indicates that there are no possible values incoming 99 // along a particular edge. In most cases, this is OK, and the Phi will 100 // be eliminated later in an Ideal call. However, we can't allow this to 101 // happen if the singleton occurs on loop entry, as the elimination of 102 // the PhiNode may cause the resulting node to migrate back to a previous 103 // loop iteration. 104 if (singleton && t == Type::TOP) { 105 // Is_Loop() == false does not confirm the absence of a loop (e.g., an 106 // irreducible loop may not be indicated by an affirmative is_Loop()); 107 // therefore, the only top we can split thru a phi is on a backedge of 108 // a loop. 109 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); 110 } 111 112 if (singleton) { 113 wins++; 114 x = ((PhaseGVN&)_igvn).makecon(t); 115 } else { 116 // We now call Identity to try to simplify the cloned node. 117 // Note that some Identity methods call phase->type(this). 118 // Make sure that the type array is big enough for 119 // our new node, even though we may throw the node away. 120 // (Note: This tweaking with igvn only works because x is a new node.) 121 _igvn.set_type(x, t); 122 // If x is a TypeNode, capture any more-precise type permanently into Node 123 // otherwise it will be not updated during igvn->transform since 124 // igvn->type(x) is set to x->Value() already. 125 x->raise_bottom_type(t); 126 Node *y = x->Identity(&_igvn); 127 if (y != x) { 128 wins++; 129 x = y; 130 } else { 131 y = _igvn.hash_find(x); 132 if (y) { 133 wins++; 134 x = y; 135 } else { 136 // Else x is a new node we are keeping 137 // We do not need register_new_node_with_optimizer 138 // because set_type has already been called. 139 _igvn._worklist.push(x); 140 } 141 } 142 } 143 if (x != the_clone && the_clone != NULL) 144 _igvn.remove_dead_node(the_clone); 145 phi->set_req( i, x ); 146 } 147 // Too few wins? 148 if (wins <= policy) { 149 _igvn.remove_dead_node(phi); 150 return NULL; 151 } 152 153 // Record Phi 154 register_new_node( phi, region ); 155 156 for (uint i2 = 1; i2 < phi->req(); i2++) { 157 Node *x = phi->in(i2); 158 // If we commoned up the cloned 'x' with another existing Node, 159 // the existing Node picks up a new use. We need to make the 160 // existing Node occur higher up so it dominates its uses. 161 Node *old_ctrl; 162 IdealLoopTree *old_loop; 163 164 if (x->is_Con()) { 165 // Constant's control is always root. 166 set_ctrl(x, C->root()); 167 continue; 168 } 169 // The occasional new node 170 if (x->_idx >= old_unique) { // Found a new, unplaced node? 171 old_ctrl = NULL; 172 old_loop = NULL; // Not in any prior loop 173 } else { 174 old_ctrl = get_ctrl(x); 175 old_loop = get_loop(old_ctrl); // Get prior loop 176 } 177 // New late point must dominate new use 178 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2)); 179 if (new_ctrl == old_ctrl) // Nothing is changed 180 continue; 181 182 IdealLoopTree *new_loop = get_loop(new_ctrl); 183 184 // Don't move x into a loop if its uses are 185 // outside of loop. Otherwise x will be cloned 186 // for each use outside of this loop. 187 IdealLoopTree *use_loop = get_loop(region); 188 if (!new_loop->is_member(use_loop) && 189 (old_loop == NULL || !new_loop->is_member(old_loop))) { 190 // Take early control, later control will be recalculated 191 // during next iteration of loop optimizations. 192 new_ctrl = get_early_ctrl(x); 193 new_loop = get_loop(new_ctrl); 194 } 195 // Set new location 196 set_ctrl(x, new_ctrl); 197 // If changing loop bodies, see if we need to collect into new body 198 if (old_loop != new_loop) { 199 if (old_loop && !old_loop->_child) 200 old_loop->_body.yank(x); 201 if (!new_loop->_child) 202 new_loop->_body.push(x); // Collect body info 203 } 204 } 205 206 return phi; 207 } 208 209 //------------------------------dominated_by------------------------------------ 210 // Replace the dominated test with an obvious true or false. Place it on the 211 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the 212 // live path up to the dominating control. 213 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) { 214 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); } 215 216 // prevdom is the dominating projection of the dominating test. 217 assert( iff->is_If(), "" ); 218 assert(iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd || iff->Opcode() == Op_RangeCheck, "Check this code when new subtype is added"); 219 int pop = prevdom->Opcode(); 220 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); 221 if (flip) { 222 if (pop == Op_IfTrue) 223 pop = Op_IfFalse; 224 else 225 pop = Op_IfTrue; 226 } 227 // 'con' is set to true or false to kill the dominated test. 228 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); 229 set_ctrl(con, C->root()); // Constant gets a new use 230 // Hack the dominated test 231 _igvn.replace_input_of(iff, 1, con); 232 233 // If I dont have a reachable TRUE and FALSE path following the IfNode then 234 // I can assume this path reaches an infinite loop. In this case it's not 235 // important to optimize the data Nodes - either the whole compilation will 236 // be tossed or this path (and all data Nodes) will go dead. 237 if (iff->outcnt() != 2) return; 238 239 // Make control-dependent data Nodes on the live path (path that will remain 240 // once the dominated IF is removed) become control-dependent on the 241 // dominating projection. 242 Node* dp = iff->as_If()->proj_out_or_null(pop == Op_IfTrue); 243 244 // Loop predicates may have depending checks which should not 245 // be skipped. For example, range check predicate has two checks 246 // for lower and upper bounds. 247 if (dp == NULL) 248 return; 249 250 ProjNode* dp_proj = dp->as_Proj(); 251 ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj(); 252 if (exclude_loop_predicate && 253 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL || 254 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) { 255 // If this is a range check (IfNode::is_range_check), do not 256 // reorder because Compile::allow_range_check_smearing might have 257 // changed the check. 258 return; // Let IGVN transformation change control dependence. 259 } 260 261 IdealLoopTree *old_loop = get_loop(dp); 262 263 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { 264 Node* cd = dp->fast_out(i); // Control-dependent node 265 if (cd->depends_only_on_test()) { 266 assert(cd->in(0) == dp, ""); 267 _igvn.replace_input_of(cd, 0, prevdom); 268 set_early_ctrl(cd); 269 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); 270 if (old_loop != new_loop) { 271 if (!old_loop->_child) old_loop->_body.yank(cd); 272 if (!new_loop->_child) new_loop->_body.push(cd); 273 } 274 --i; 275 --imax; 276 } 277 } 278 } 279 280 //------------------------------has_local_phi_input---------------------------- 281 // Return TRUE if 'n' has Phi inputs from its local block and no other 282 // block-local inputs (all non-local-phi inputs come from earlier blocks) 283 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { 284 Node *n_ctrl = get_ctrl(n); 285 // See if some inputs come from a Phi in this block, or from before 286 // this block. 287 uint i; 288 for( i = 1; i < n->req(); i++ ) { 289 Node *phi = n->in(i); 290 if( phi->is_Phi() && phi->in(0) == n_ctrl ) 291 break; 292 } 293 if( i >= n->req() ) 294 return NULL; // No Phi inputs; nowhere to clone thru 295 296 // Check for inputs created between 'n' and the Phi input. These 297 // must split as well; they have already been given the chance 298 // (courtesy of a post-order visit) and since they did not we must 299 // recover the 'cost' of splitting them by being very profitable 300 // when splitting 'n'. Since this is unlikely we simply give up. 301 for( i = 1; i < n->req(); i++ ) { 302 Node *m = n->in(i); 303 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { 304 // We allow the special case of AddP's with no local inputs. 305 // This allows us to split-up address expressions. 306 if (m->is_AddP() && 307 get_ctrl(m->in(2)) != n_ctrl && 308 get_ctrl(m->in(3)) != n_ctrl) { 309 // Move the AddP up to dominating point 310 Node* c = find_non_split_ctrl(idom(n_ctrl)); 311 if (c->is_OuterStripMinedLoop()) { 312 c->as_Loop()->verify_strip_mined(1); 313 c = c->in(LoopNode::EntryControl); 314 } 315 set_ctrl_and_loop(m, c); 316 continue; 317 } 318 return NULL; 319 } 320 assert(m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control"); 321 } 322 323 return n_ctrl; 324 } 325 326 //------------------------------remix_address_expressions---------------------- 327 // Rework addressing expressions to get the most loop-invariant stuff 328 // moved out. We'd like to do all associative operators, but it's especially 329 // important (common) to do address expressions. 330 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { 331 if (!has_ctrl(n)) return NULL; 332 Node *n_ctrl = get_ctrl(n); 333 IdealLoopTree *n_loop = get_loop(n_ctrl); 334 335 // See if 'n' mixes loop-varying and loop-invariant inputs and 336 // itself is loop-varying. 337 338 // Only interested in binary ops (and AddP) 339 if( n->req() < 3 || n->req() > 4 ) return NULL; 340 341 Node *n1_ctrl = get_ctrl(n->in( 1)); 342 Node *n2_ctrl = get_ctrl(n->in( 2)); 343 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); 344 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); 345 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); 346 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); 347 348 // Does one of my inputs spin in a tighter loop than self? 349 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || 350 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || 351 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) 352 return NULL; // Leave well enough alone 353 354 // Is at least one of my inputs loop-invariant? 355 if( n1_loop == n_loop && 356 n2_loop == n_loop && 357 n3_loop == n_loop ) 358 return NULL; // No loop-invariant inputs 359 360 361 int n_op = n->Opcode(); 362 363 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). 364 if( n_op == Op_LShiftI ) { 365 // Scale is loop invariant 366 Node *scale = n->in(2); 367 Node *scale_ctrl = get_ctrl(scale); 368 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); 369 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) 370 return NULL; 371 const TypeInt *scale_t = scale->bottom_type()->isa_int(); 372 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) 373 return NULL; // Dont bother with byte/short masking 374 // Add must vary with loop (else shift would be loop-invariant) 375 Node *add = n->in(1); 376 Node *add_ctrl = get_ctrl(add); 377 IdealLoopTree *add_loop = get_loop(add_ctrl); 378 //assert( n_loop == add_loop, "" ); 379 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops 380 381 // Convert I-V into I+ (0-V); same for V-I 382 if( add->Opcode() == Op_SubI && 383 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { 384 Node *zero = _igvn.intcon(0); 385 set_ctrl(zero, C->root()); 386 Node *neg = new SubINode( _igvn.intcon(0), add->in(2) ); 387 register_new_node( neg, get_ctrl(add->in(2) ) ); 388 add = new AddINode( add->in(1), neg ); 389 register_new_node( add, add_ctrl ); 390 } 391 if( add->Opcode() != Op_AddI ) return NULL; 392 // See if one add input is loop invariant 393 Node *add_var = add->in(1); 394 Node *add_var_ctrl = get_ctrl(add_var); 395 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); 396 Node *add_invar = add->in(2); 397 Node *add_invar_ctrl = get_ctrl(add_invar); 398 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); 399 if( add_var_loop == n_loop ) { 400 } else if( add_invar_loop == n_loop ) { 401 // Swap to find the invariant part 402 add_invar = add_var; 403 add_invar_ctrl = add_var_ctrl; 404 add_invar_loop = add_var_loop; 405 add_var = add->in(2); 406 Node *add_var_ctrl = get_ctrl(add_var); 407 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); 408 } else // Else neither input is loop invariant 409 return NULL; 410 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) 411 return NULL; // No invariant part of the add? 412 413 // Yes! Reshape address expression! 414 Node *inv_scale = new LShiftINode( add_invar, scale ); 415 Node *inv_scale_ctrl = 416 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? 417 add_invar_ctrl : scale_ctrl; 418 register_new_node( inv_scale, inv_scale_ctrl ); 419 Node *var_scale = new LShiftINode( add_var, scale ); 420 register_new_node( var_scale, n_ctrl ); 421 Node *var_add = new AddINode( var_scale, inv_scale ); 422 register_new_node( var_add, n_ctrl ); 423 _igvn.replace_node( n, var_add ); 424 return var_add; 425 } 426 427 // Replace (I+V) with (V+I) 428 if( n_op == Op_AddI || 429 n_op == Op_AddL || 430 n_op == Op_AddF || 431 n_op == Op_AddD || 432 n_op == Op_MulI || 433 n_op == Op_MulL || 434 n_op == Op_MulF || 435 n_op == Op_MulD ) { 436 if( n2_loop == n_loop ) { 437 assert( n1_loop != n_loop, "" ); 438 n->swap_edges(1, 2); 439 } 440 } 441 442 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), 443 // but not if I2 is a constant. 444 if( n_op == Op_AddP ) { 445 if( n2_loop == n_loop && n3_loop != n_loop ) { 446 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { 447 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); 448 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); 449 IdealLoopTree *n22loop = get_loop( n22_ctrl ); 450 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); 451 if( n22loop != n_loop && n22loop->is_member(n_loop) && 452 n23_loop == n_loop ) { 453 Node *add1 = new AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); 454 // Stuff new AddP in the loop preheader 455 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); 456 Node *add2 = new AddPNode( n->in(1), add1, n->in(2)->in(3) ); 457 register_new_node( add2, n_ctrl ); 458 _igvn.replace_node( n, add2 ); 459 return add2; 460 } 461 } 462 } 463 464 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) 465 if (n2_loop != n_loop && n3_loop == n_loop) { 466 if (n->in(3)->Opcode() == Op_AddX) { 467 Node *V = n->in(3)->in(1); 468 Node *I = n->in(3)->in(2); 469 if (is_member(n_loop,get_ctrl(V))) { 470 } else { 471 Node *tmp = V; V = I; I = tmp; 472 } 473 if (!is_member(n_loop,get_ctrl(I))) { 474 Node *add1 = new AddPNode(n->in(1), n->in(2), I); 475 // Stuff new AddP in the loop preheader 476 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl)); 477 Node *add2 = new AddPNode(n->in(1), add1, V); 478 register_new_node(add2, n_ctrl); 479 _igvn.replace_node(n, add2); 480 return add2; 481 } 482 } 483 } 484 } 485 486 return NULL; 487 } 488 489 //------------------------------conditional_move------------------------------- 490 // Attempt to replace a Phi with a conditional move. We have some pretty 491 // strict profitability requirements. All Phis at the merge point must 492 // be converted, so we can remove the control flow. We need to limit the 493 // number of c-moves to a small handful. All code that was in the side-arms 494 // of the CFG diamond is now speculatively executed. This code has to be 495 // "cheap enough". We are pretty much limited to CFG diamonds that merge 496 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. 497 Node *PhaseIdealLoop::conditional_move( Node *region ) { 498 499 assert(region->is_Region(), "sanity check"); 500 if (region->req() != 3) return NULL; 501 502 // Check for CFG diamond 503 Node *lp = region->in(1); 504 Node *rp = region->in(2); 505 if (!lp || !rp) return NULL; 506 Node *lp_c = lp->in(0); 507 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL; 508 IfNode *iff = lp_c->as_If(); 509 510 // Check for ops pinned in an arm of the diamond. 511 // Can't remove the control flow in this case 512 if (lp->outcnt() > 1) return NULL; 513 if (rp->outcnt() > 1) return NULL; 514 515 IdealLoopTree* r_loop = get_loop(region); 516 assert(r_loop == get_loop(iff), "sanity"); 517 // Always convert to CMOVE if all results are used only outside this loop. 518 bool used_inside_loop = (r_loop == _ltree_root); 519 520 // Check profitability 521 int cost = 0; 522 int phis = 0; 523 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 524 Node *out = region->fast_out(i); 525 if (!out->is_Phi()) continue; // Ignore other control edges, etc 526 phis++; 527 PhiNode* phi = out->as_Phi(); 528 BasicType bt = phi->type()->basic_type(); 529 switch (bt) { 530 case T_DOUBLE: 531 case T_FLOAT: 532 if (C->use_cmove()) { 533 continue; //TODO: maybe we want to add some cost 534 } 535 cost += Matcher::float_cmove_cost(); // Could be very expensive 536 break; 537 case T_LONG: { 538 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's 539 } 540 case T_INT: // These all CMOV fine 541 case T_ADDRESS: { // (RawPtr) 542 cost++; 543 break; 544 } 545 case T_NARROWOOP: // Fall through 546 case T_OBJECT: { // Base oops are OK, but not derived oops 547 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); 548 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a 549 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus 550 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we 551 // have a Phi for the base here that we convert to a CMOVE all is well 552 // and good. But if the base is dead, we'll not make a CMOVE. Later 553 // the allocator will have to produce a base by creating a CMOVE of the 554 // relevant bases. This puts the allocator in the business of 555 // manufacturing expensive instructions, generally a bad plan. 556 // Just Say No to Conditionally-Moved Derived Pointers. 557 if (tp && tp->offset() != 0) 558 return NULL; 559 cost++; 560 break; 561 } 562 default: 563 return NULL; // In particular, can't do memory or I/O 564 } 565 // Add in cost any speculative ops 566 for (uint j = 1; j < region->req(); j++) { 567 Node *proj = region->in(j); 568 Node *inp = phi->in(j); 569 if (get_ctrl(inp) == proj) { // Found local op 570 cost++; 571 // Check for a chain of dependent ops; these will all become 572 // speculative in a CMOV. 573 for (uint k = 1; k < inp->req(); k++) 574 if (get_ctrl(inp->in(k)) == proj) 575 cost += ConditionalMoveLimit; // Too much speculative goo 576 } 577 } 578 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. 579 // This will likely Split-If, a higher-payoff operation. 580 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { 581 Node* use = phi->fast_out(k); 582 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr()) 583 cost += ConditionalMoveLimit; 584 // Is there a use inside the loop? 585 // Note: check only basic types since CMoveP is pinned. 586 if (!used_inside_loop && is_java_primitive(bt)) { 587 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use); 588 if (r_loop == u_loop || r_loop->is_member(u_loop)) { 589 used_inside_loop = true; 590 } 591 } 592 } 593 }//for 594 Node* bol = iff->in(1); 595 assert(bol->Opcode() == Op_Bool, ""); 596 int cmp_op = bol->in(1)->Opcode(); 597 // It is expensive to generate flags from a float compare. 598 // Avoid duplicated float compare. 599 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; 600 601 float infrequent_prob = PROB_UNLIKELY_MAG(3); 602 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop. 603 if (used_inside_loop) { 604 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo 605 606 // BlockLayoutByFrequency optimization moves infrequent branch 607 // from hot path. No point in CMOV'ing in such case (110 is used 608 // instead of 100 to take into account not exactness of float value). 609 if (BlockLayoutByFrequency) { 610 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f); 611 } 612 } 613 // Check for highly predictable branch. No point in CMOV'ing if 614 // we are going to predict accurately all the time. 615 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) { 616 //keep going 617 } else if (iff->_prob < infrequent_prob || 618 iff->_prob > (1.0f - infrequent_prob)) 619 return NULL; 620 621 // -------------- 622 // Now replace all Phis with CMOV's 623 Node *cmov_ctrl = iff->in(0); 624 uint flip = (lp->Opcode() == Op_IfTrue); 625 Node_List wq; 626 while (1) { 627 PhiNode* phi = NULL; 628 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 629 Node *out = region->fast_out(i); 630 if (out->is_Phi()) { 631 phi = out->as_Phi(); 632 break; 633 } 634 } 635 if (phi == NULL) break; 636 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); } 637 // Move speculative ops 638 wq.push(phi); 639 while (wq.size() > 0) { 640 Node *n = wq.pop(); 641 for (uint j = 1; j < n->req(); j++) { 642 Node* m = n->in(j); 643 if (m != NULL && !is_dominator(get_ctrl(m), cmov_ctrl)) { 644 #ifndef PRODUCT 645 if (PrintOpto && VerifyLoopOptimizations) { 646 tty->print(" speculate: "); 647 m->dump(); 648 } 649 #endif 650 set_ctrl(m, cmov_ctrl); 651 wq.push(m); 652 } 653 } 654 } 655 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi)); 656 register_new_node( cmov, cmov_ctrl ); 657 _igvn.replace_node( phi, cmov ); 658 #ifndef PRODUCT 659 if (TraceLoopOpts) { 660 tty->print("CMOV "); 661 r_loop->dump_head(); 662 if (Verbose) { 663 bol->in(1)->dump(1); 664 cmov->dump(1); 665 } 666 } 667 if (VerifyLoopOptimizations) verify(); 668 #endif 669 } 670 671 // The useless CFG diamond will fold up later; see the optimization in 672 // RegionNode::Ideal. 673 _igvn._worklist.push(region); 674 675 return iff->in(1); 676 } 677 678 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) { 679 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) { 680 Node* u = m->fast_out(i); 681 if (u->is_CFG()) { 682 if (u->Opcode() == Op_NeverBranch) { 683 u = ((NeverBranchNode*)u)->proj_out(0); 684 enqueue_cfg_uses(u, wq); 685 } else { 686 wq.push(u); 687 } 688 } 689 } 690 } 691 692 // Try moving a store out of a loop, right before the loop 693 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) { 694 // Store has to be first in the loop body 695 IdealLoopTree *n_loop = get_loop(n_ctrl); 696 if (n->is_Store() && n_loop != _ltree_root && n_loop->is_loop() && n->in(0) != NULL) { 697 Node* address = n->in(MemNode::Address); 698 Node* value = n->in(MemNode::ValueIn); 699 Node* mem = n->in(MemNode::Memory); 700 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 701 IdealLoopTree* value_loop = get_loop(get_ctrl(value)); 702 703 // - address and value must be loop invariant 704 // - memory must be a memory Phi for the loop 705 // - Store must be the only store on this memory slice in the 706 // loop: if there's another store following this one then value 707 // written at iteration i by the second store could be overwritten 708 // at iteration i+n by the first store: it's not safe to move the 709 // first store out of the loop 710 // - nothing must observe the memory Phi: it guarantees no read 711 // before the store, we are also guaranteed the store post 712 // dominates the loop head (ignoring a possible early 713 // exit). Otherwise there would be extra Phi involved between the 714 // loop's Phi and the store. 715 // - there must be no early exit from the loop before the Store 716 // (such an exit most of the time would be an extra use of the 717 // memory Phi but sometimes is a bottom memory Phi that takes the 718 // store as input). 719 720 if (!n_loop->is_member(address_loop) && 721 !n_loop->is_member(value_loop) && 722 mem->is_Phi() && mem->in(0) == n_loop->_head && 723 mem->outcnt() == 1 && 724 mem->in(LoopNode::LoopBackControl) == n) { 725 726 assert(n_loop->_tail != NULL, "need a tail"); 727 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop"); 728 729 // Verify that there's no early exit of the loop before the store. 730 bool ctrl_ok = false; 731 { 732 // Follow control from loop head until n, we exit the loop or 733 // we reach the tail 734 ResourceMark rm; 735 Unique_Node_List wq; 736 wq.push(n_loop->_head); 737 738 for (uint next = 0; next < wq.size(); ++next) { 739 Node *m = wq.at(next); 740 if (m == n->in(0)) { 741 ctrl_ok = true; 742 continue; 743 } 744 assert(!has_ctrl(m), "should be CFG"); 745 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) { 746 ctrl_ok = false; 747 break; 748 } 749 enqueue_cfg_uses(m, wq); 750 if (wq.size() > 10) { 751 ctrl_ok = false; 752 break; 753 } 754 } 755 } 756 if (ctrl_ok) { 757 // move the Store 758 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem); 759 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl)); 760 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl)); 761 // Disconnect the phi now. An empty phi can confuse other 762 // optimizations in this pass of loop opts. 763 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl)); 764 n_loop->_body.yank(mem); 765 766 set_ctrl_and_loop(n, n->in(0)); 767 768 return n; 769 } 770 } 771 } 772 return NULL; 773 } 774 775 // Try moving a store out of a loop, right after the loop 776 void PhaseIdealLoop::try_move_store_after_loop(Node* n) { 777 if (n->is_Store() && n->in(0) != NULL) { 778 Node *n_ctrl = get_ctrl(n); 779 IdealLoopTree *n_loop = get_loop(n_ctrl); 780 // Store must be in a loop 781 if (n_loop != _ltree_root && !n_loop->_irreducible) { 782 Node* address = n->in(MemNode::Address); 783 Node* value = n->in(MemNode::ValueIn); 784 IdealLoopTree* address_loop = get_loop(get_ctrl(address)); 785 // address must be loop invariant 786 if (!n_loop->is_member(address_loop)) { 787 // Store must be last on this memory slice in the loop and 788 // nothing in the loop must observe it 789 Node* phi = NULL; 790 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 791 Node* u = n->fast_out(i); 792 if (has_ctrl(u)) { // control use? 793 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); 794 if (!n_loop->is_member(u_loop)) { 795 continue; 796 } 797 if (u->is_Phi() && u->in(0) == n_loop->_head) { 798 assert(_igvn.type(u) == Type::MEMORY, "bad phi"); 799 // multiple phis on the same slice are possible 800 if (phi != NULL) { 801 return; 802 } 803 phi = u; 804 continue; 805 } 806 } 807 return; 808 } 809 if (phi != NULL) { 810 // Nothing in the loop before the store (next iteration) 811 // must observe the stored value 812 bool mem_ok = true; 813 { 814 ResourceMark rm; 815 Unique_Node_List wq; 816 wq.push(phi); 817 for (uint next = 0; next < wq.size() && mem_ok; ++next) { 818 Node *m = wq.at(next); 819 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) { 820 Node* u = m->fast_out(i); 821 if (u->is_Store() || u->is_Phi()) { 822 if (u != n) { 823 wq.push(u); 824 mem_ok = (wq.size() <= 10); 825 } 826 } else { 827 mem_ok = false; 828 break; 829 } 830 } 831 } 832 } 833 if (mem_ok) { 834 // Move the store out of the loop if the LCA of all 835 // users (except for the phi) is outside the loop. 836 Node* hook = new Node(1); 837 _igvn.rehash_node_delayed(phi); 838 int count = phi->replace_edge(n, hook); 839 assert(count > 0, "inconsistent phi"); 840 841 // Compute latest point this store can go 842 Node* lca = get_late_ctrl(n, get_ctrl(n)); 843 if (n_loop->is_member(get_loop(lca))) { 844 // LCA is in the loop - bail out 845 _igvn.replace_node(hook, n); 846 return; 847 } 848 #ifdef ASSERT 849 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) { 850 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined"); 851 n_loop->_head->as_Loop()->verify_strip_mined(1); 852 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop(); 853 IdealLoopTree* outer_loop = get_loop(outer); 854 assert(n_loop->_parent == outer_loop, "broken loop tree"); 855 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state"); 856 } 857 #endif 858 859 // Move store out of the loop 860 _igvn.replace_node(hook, n->in(MemNode::Memory)); 861 _igvn.replace_input_of(n, 0, lca); 862 set_ctrl_and_loop(n, lca); 863 864 // Disconnect the phi now. An empty phi can confuse other 865 // optimizations in this pass of loop opts.. 866 if (phi->in(LoopNode::LoopBackControl) == phi) { 867 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl)); 868 n_loop->_body.yank(phi); 869 } 870 } 871 } 872 } 873 } 874 } 875 } 876 877 //------------------------------split_if_with_blocks_pre----------------------- 878 // Do the real work in a non-recursive function. Data nodes want to be 879 // cloned in the pre-order so they can feed each other nicely. 880 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { 881 // Cloning these guys is unlikely to win 882 int n_op = n->Opcode(); 883 if( n_op == Op_MergeMem ) return n; 884 if( n->is_Proj() ) return n; 885 // Do not clone-up CmpFXXX variations, as these are always 886 // followed by a CmpI 887 if( n->is_Cmp() ) return n; 888 // Attempt to use a conditional move instead of a phi/branch 889 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { 890 Node *cmov = conditional_move( n ); 891 if( cmov ) return cmov; 892 } 893 if( n->is_CFG() || n->is_LoadStore() ) 894 return n; 895 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd 896 n_op == Op_Opaque2 ) { 897 if( !C->major_progress() ) // If chance of no more loop opts... 898 _igvn._worklist.push(n); // maybe we'll remove them 899 return n; 900 } 901 902 if( n->is_Con() ) return n; // No cloning for Con nodes 903 904 Node *n_ctrl = get_ctrl(n); 905 if( !n_ctrl ) return n; // Dead node 906 907 Node* res = try_move_store_before_loop(n, n_ctrl); 908 if (res != NULL) { 909 return n; 910 } 911 912 // Attempt to remix address expressions for loop invariants 913 Node *m = remix_address_expressions( n ); 914 if( m ) return m; 915 916 if (n->is_ConstraintCast()) { 917 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this); 918 // ConstraintCastNode::dominating_cast() uses node control input to determine domination. 919 // Node control inputs don't necessarily agree with loop control info (due to 920 // transformations happened in between), thus additional dominance check is needed 921 // to keep loop info valid. 922 if (dom_cast != NULL && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) { 923 _igvn.replace_node(n, dom_cast); 924 return dom_cast; 925 } 926 } 927 928 // Determine if the Node has inputs from some local Phi. 929 // Returns the block to clone thru. 930 Node *n_blk = has_local_phi_input( n ); 931 if( !n_blk ) return n; 932 933 // Do not clone the trip counter through on a CountedLoop 934 // (messes up the canonical shape). 935 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; 936 937 // Check for having no control input; not pinned. Allow 938 // dominating control. 939 if (n->in(0)) { 940 Node *dom = idom(n_blk); 941 if (dom_lca(n->in(0), dom) != n->in(0)) { 942 return n; 943 } 944 } 945 // Policy: when is it profitable. You must get more wins than 946 // policy before it is considered profitable. Policy is usually 0, 947 // so 1 win is considered profitable. Big merges will require big 948 // cloning, so get a larger policy. 949 int policy = n_blk->req() >> 2; 950 951 // If the loop is a candidate for range check elimination, 952 // delay splitting through it's phi until a later loop optimization 953 if (n_blk->is_CountedLoop()) { 954 IdealLoopTree *lp = get_loop(n_blk); 955 if (lp && lp->_rce_candidate) { 956 return n; 957 } 958 } 959 960 // Use same limit as split_if_with_blocks_post 961 if( C->live_nodes() > 35000 ) return n; // Method too big 962 963 // Split 'n' through the merge point if it is profitable 964 Node *phi = split_thru_phi( n, n_blk, policy ); 965 if (!phi) return n; 966 967 // Found a Phi to split thru! 968 // Replace 'n' with the new phi 969 _igvn.replace_node( n, phi ); 970 // Moved a load around the loop, 'en-registering' something. 971 if (n_blk->is_Loop() && n->is_Load() && 972 !phi->in(LoopNode::LoopBackControl)->is_Load()) 973 C->set_major_progress(); 974 975 return phi; 976 } 977 978 static bool merge_point_too_heavy(Compile* C, Node* region) { 979 // Bail out if the region and its phis have too many users. 980 int weight = 0; 981 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 982 weight += region->fast_out(i)->outcnt(); 983 } 984 int nodes_left = C->max_node_limit() - C->live_nodes(); 985 if (weight * 8 > nodes_left) { 986 if (PrintOpto) { 987 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); 988 } 989 return true; 990 } else { 991 return false; 992 } 993 } 994 995 static bool merge_point_safe(Node* region) { 996 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode 997 // having a PhiNode input. This sidesteps the dangerous case where the split 998 // ConvI2LNode may become TOP if the input Value() does not 999 // overlap the ConvI2L range, leaving a node which may not dominate its 1000 // uses. 1001 // A better fix for this problem can be found in the BugTraq entry, but 1002 // expediency for Mantis demands this hack. 1003 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop 1004 // split_if_with_blocks from splitting a block because we could not move around 1005 // the FastLockNode. 1006 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 1007 Node* n = region->fast_out(i); 1008 if (n->is_Phi()) { 1009 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 1010 Node* m = n->fast_out(j); 1011 if (m->is_FastLock()) 1012 return false; 1013 #ifdef _LP64 1014 if (m->Opcode() == Op_ConvI2L) 1015 return false; 1016 if (m->is_CastII() && m->isa_CastII()->has_range_check()) { 1017 return false; 1018 } 1019 #endif 1020 } 1021 } 1022 } 1023 return true; 1024 } 1025 1026 1027 //------------------------------place_near_use--------------------------------- 1028 // Place some computation next to use but not inside inner loops. 1029 // For inner loop uses move it to the preheader area. 1030 Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { 1031 IdealLoopTree *u_loop = get_loop( useblock ); 1032 return (u_loop->_irreducible || u_loop->_child) 1033 ? useblock 1034 : u_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl); 1035 } 1036 1037 1038 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) { 1039 if (!n->is_If()) { 1040 return false; 1041 } 1042 if (!n->in(0)->is_Region()) { 1043 return false; 1044 } 1045 Node* region = n->in(0); 1046 Node* dom = idom(region); 1047 if (!dom->is_If() || dom->in(1) != n->in(1)) { 1048 return false; 1049 } 1050 IfNode* dom_if = dom->as_If(); 1051 Node* proj_true = dom_if->proj_out(1); 1052 Node* proj_false = dom_if->proj_out(0); 1053 1054 for (uint i = 1; i < region->req(); i++) { 1055 if (is_dominator(proj_true, region->in(i))) { 1056 continue; 1057 } 1058 if (is_dominator(proj_false, region->in(i))) { 1059 continue; 1060 } 1061 return false; 1062 } 1063 1064 return true; 1065 } 1066 1067 bool PhaseIdealLoop::can_split_if(Node *n_ctrl) { 1068 if (C->live_nodes() > 35000) { 1069 return false; // Method too big 1070 } 1071 1072 // Do not do 'split-if' if irreducible loops are present. 1073 if (_has_irreducible_loops) { 1074 return false; 1075 } 1076 1077 if (merge_point_too_heavy(C, n_ctrl)) { 1078 return false; 1079 } 1080 1081 // Do not do 'split-if' if some paths are dead. First do dead code 1082 // elimination and then see if its still profitable. 1083 for (uint i = 1; i < n_ctrl->req(); i++) { 1084 if (n_ctrl->in(i) == C->top()) { 1085 return false; 1086 } 1087 } 1088 1089 // If trying to do a 'Split-If' at the loop head, it is only 1090 // profitable if the cmp folds up on BOTH paths. Otherwise we 1091 // risk peeling a loop forever. 1092 1093 // CNC - Disabled for now. Requires careful handling of loop 1094 // body selection for the cloned code. Also, make sure we check 1095 // for any input path not being in the same loop as n_ctrl. For 1096 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' 1097 // because the alternative loop entry points won't be converted 1098 // into LoopNodes. 1099 IdealLoopTree *n_loop = get_loop(n_ctrl); 1100 for (uint j = 1; j < n_ctrl->req(); j++) { 1101 if (get_loop(n_ctrl->in(j)) != n_loop) { 1102 return false; 1103 } 1104 } 1105 1106 // Check for safety of the merge point. 1107 if (!merge_point_safe(n_ctrl)) { 1108 return false; 1109 } 1110 1111 return true; 1112 } 1113 1114 //------------------------------split_if_with_blocks_post---------------------- 1115 // Do the real work in a non-recursive function. CFG hackery wants to be 1116 // in the post-order, so it can dirty the I-DOM info and not use the dirtied 1117 // info. 1118 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) { 1119 1120 // Cloning Cmp through Phi's involves the split-if transform. 1121 // FastLock is not used by an If 1122 if (n->is_Cmp() && !n->is_FastLock()) { 1123 Node *n_ctrl = get_ctrl(n); 1124 // Determine if the Node has inputs from some local Phi. 1125 // Returns the block to clone thru. 1126 Node *n_blk = has_local_phi_input(n); 1127 if (n_blk != n_ctrl) { 1128 return; 1129 } 1130 1131 if (!can_split_if(n_ctrl)) { 1132 return; 1133 } 1134 1135 if (n->outcnt() != 1) { 1136 return; // Multiple bool's from 1 compare? 1137 } 1138 Node *bol = n->unique_out(); 1139 assert(bol->is_Bool(), "expect a bool here"); 1140 if (bol->outcnt() != 1) { 1141 return;// Multiple branches from 1 compare? 1142 } 1143 Node *iff = bol->unique_out(); 1144 1145 // Check some safety conditions 1146 if (iff->is_If()) { // Classic split-if? 1147 if (iff->in(0) != n_ctrl) { 1148 return; // Compare must be in same blk as if 1149 } 1150 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE 1151 // Can't split CMove with different control edge. 1152 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) { 1153 return; 1154 } 1155 if (get_ctrl(iff->in(2)) == n_ctrl || 1156 get_ctrl(iff->in(3)) == n_ctrl) { 1157 return; // Inputs not yet split-up 1158 } 1159 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) { 1160 return; // Loop-invar test gates loop-varying CMOVE 1161 } 1162 } else { 1163 return; // some other kind of node, such as an Allocate 1164 } 1165 1166 // When is split-if profitable? Every 'win' on means some control flow 1167 // goes dead, so it's almost always a win. 1168 int policy = 0; 1169 // Split compare 'n' through the merge point if it is profitable 1170 Node *phi = split_thru_phi( n, n_ctrl, policy); 1171 if (!phi) { 1172 return; 1173 } 1174 1175 // Found a Phi to split thru! 1176 // Replace 'n' with the new phi 1177 _igvn.replace_node(n, phi); 1178 1179 // Now split the bool up thru the phi 1180 Node *bolphi = split_thru_phi(bol, n_ctrl, -1); 1181 guarantee(bolphi != NULL, "null boolean phi node"); 1182 1183 _igvn.replace_node(bol, bolphi); 1184 assert(iff->in(1) == bolphi, ""); 1185 1186 if (bolphi->Value(&_igvn)->singleton()) { 1187 return; 1188 } 1189 1190 // Conditional-move? Must split up now 1191 if (!iff->is_If()) { 1192 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1); 1193 _igvn.replace_node(iff, cmovphi); 1194 return; 1195 } 1196 1197 // Now split the IF 1198 do_split_if(iff); 1199 return; 1200 } 1201 1202 // Two identical ifs back to back can be merged 1203 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) { 1204 Node *n_ctrl = n->in(0); 1205 PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1)); 1206 IfNode* dom_if = idom(n_ctrl)->as_If(); 1207 Node* proj_true = dom_if->proj_out(1); 1208 Node* proj_false = dom_if->proj_out(0); 1209 Node* con_true = _igvn.makecon(TypeInt::ONE); 1210 Node* con_false = _igvn.makecon(TypeInt::ZERO); 1211 1212 for (uint i = 1; i < n_ctrl->req(); i++) { 1213 if (is_dominator(proj_true, n_ctrl->in(i))) { 1214 bolphi->init_req(i, con_true); 1215 } else { 1216 assert(is_dominator(proj_false, n_ctrl->in(i)), "bad if"); 1217 bolphi->init_req(i, con_false); 1218 } 1219 } 1220 register_new_node(bolphi, n_ctrl); 1221 _igvn.replace_input_of(n, 1, bolphi); 1222 1223 // Now split the IF 1224 do_split_if(n); 1225 return; 1226 } 1227 1228 // Check for an IF ready to split; one that has its 1229 // condition codes input coming from a Phi at the block start. 1230 int n_op = n->Opcode(); 1231 1232 // Check for an IF being dominated by another IF same test 1233 if (n_op == Op_If || 1234 n_op == Op_RangeCheck) { 1235 Node *bol = n->in(1); 1236 uint max = bol->outcnt(); 1237 // Check for same test used more than once? 1238 if (max > 1 && bol->is_Bool()) { 1239 // Search up IDOMs to see if this IF is dominated. 1240 Node *cutoff = get_ctrl(bol); 1241 1242 // Now search up IDOMs till cutoff, looking for a dominating test 1243 Node *prevdom = n; 1244 Node *dom = idom(prevdom); 1245 while (dom != cutoff) { 1246 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) { 1247 // Replace the dominated test with an obvious true or false. 1248 // Place it on the IGVN worklist for later cleanup. 1249 C->set_major_progress(); 1250 dominated_by(prevdom, n, false, true); 1251 #ifndef PRODUCT 1252 if( VerifyLoopOptimizations ) verify(); 1253 #endif 1254 return; 1255 } 1256 prevdom = dom; 1257 dom = idom(prevdom); 1258 } 1259 } 1260 } 1261 1262 // See if a shared loop-varying computation has no loop-varying uses. 1263 // Happens if something is only used for JVM state in uncommon trap exits, 1264 // like various versions of induction variable+offset. Clone the 1265 // computation per usage to allow it to sink out of the loop. 1266 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) 1267 Node *n_ctrl = get_ctrl(n); 1268 IdealLoopTree *n_loop = get_loop(n_ctrl); 1269 if( n_loop != _ltree_root ) { 1270 DUIterator_Fast imax, i = n->fast_outs(imax); 1271 for (; i < imax; i++) { 1272 Node* u = n->fast_out(i); 1273 if( !has_ctrl(u) ) break; // Found control user 1274 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); 1275 if( u_loop == n_loop ) break; // Found loop-varying use 1276 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop 1277 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 1278 } 1279 bool did_break = (i < imax); // Did we break out of the previous loop? 1280 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! 1281 Node *late_load_ctrl = NULL; 1282 if (n->is_Load()) { 1283 // If n is a load, get and save the result from get_late_ctrl(), 1284 // to be later used in calculating the control for n's clones. 1285 clear_dom_lca_tags(); 1286 late_load_ctrl = get_late_ctrl(n, n_ctrl); 1287 } 1288 // If n is a load, and the late control is the same as the current 1289 // control, then the cloning of n is a pointless exercise, because 1290 // GVN will ensure that we end up where we started. 1291 if (!n->is_Load() || late_load_ctrl != n_ctrl) { 1292 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { 1293 Node *u = n->last_out(j); // Clone private computation per use 1294 _igvn.rehash_node_delayed(u); 1295 Node *x = n->clone(); // Clone computation 1296 Node *x_ctrl = NULL; 1297 if( u->is_Phi() ) { 1298 // Replace all uses of normal nodes. Replace Phi uses 1299 // individually, so the separate Nodes can sink down 1300 // different paths. 1301 uint k = 1; 1302 while( u->in(k) != n ) k++; 1303 u->set_req( k, x ); 1304 // x goes next to Phi input path 1305 x_ctrl = u->in(0)->in(k); 1306 --j; 1307 } else { // Normal use 1308 // Replace all uses 1309 for( uint k = 0; k < u->req(); k++ ) { 1310 if( u->in(k) == n ) { 1311 u->set_req( k, x ); 1312 --j; 1313 } 1314 } 1315 x_ctrl = get_ctrl(u); 1316 } 1317 1318 // Find control for 'x' next to use but not inside inner loops. 1319 // For inner loop uses get the preheader area. 1320 x_ctrl = place_near_use(x_ctrl); 1321 1322 if (n->is_Load()) { 1323 // For loads, add a control edge to a CFG node outside of the loop 1324 // to force them to not combine and return back inside the loop 1325 // during GVN optimization (4641526). 1326 // 1327 // Because we are setting the actual control input, factor in 1328 // the result from get_late_ctrl() so we respect any 1329 // anti-dependences. (6233005). 1330 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); 1331 1332 // Don't allow the control input to be a CFG splitting node. 1333 // Such nodes should only have ProjNodes as outs, e.g. IfNode 1334 // should only have IfTrueNode and IfFalseNode (4985384). 1335 x_ctrl = find_non_split_ctrl(x_ctrl); 1336 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); 1337 1338 x->set_req(0, x_ctrl); 1339 } 1340 register_new_node(x, x_ctrl); 1341 1342 // Some institutional knowledge is needed here: 'x' is 1343 // yanked because if the optimizer runs GVN on it all the 1344 // cloned x's will common up and undo this optimization and 1345 // be forced back in the loop. This is annoying because it 1346 // makes +VerifyOpto report false-positives on progress. I 1347 // tried setting control edges on the x's to force them to 1348 // not combine, but the matching gets worried when it tries 1349 // to fold a StoreP and an AddP together (as part of an 1350 // address expression) and the AddP and StoreP have 1351 // different controls. 1352 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x); 1353 } 1354 _igvn.remove_dead_node(n); 1355 } 1356 } 1357 } 1358 } 1359 1360 try_move_store_after_loop(n); 1361 1362 // Check for Opaque2's who's loop has disappeared - who's input is in the 1363 // same loop nest as their output. Remove 'em, they are no longer useful. 1364 if( n_op == Op_Opaque2 && 1365 n->in(1) != NULL && 1366 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { 1367 _igvn.replace_node( n, n->in(1) ); 1368 } 1369 } 1370 1371 //------------------------------split_if_with_blocks--------------------------- 1372 // Check for aggressive application of 'split-if' optimization, 1373 // using basic block level info. 1374 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { 1375 Node *n = C->root(); 1376 visited.set(n->_idx); // first, mark node as visited 1377 // Do pre-visit work for root 1378 n = split_if_with_blocks_pre( n ); 1379 uint cnt = n->outcnt(); 1380 uint i = 0; 1381 while (true) { 1382 // Visit all children 1383 if (i < cnt) { 1384 Node* use = n->raw_out(i); 1385 ++i; 1386 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { 1387 // Now do pre-visit work for this use 1388 use = split_if_with_blocks_pre( use ); 1389 nstack.push(n, i); // Save parent and next use's index. 1390 n = use; // Process all children of current use. 1391 cnt = use->outcnt(); 1392 i = 0; 1393 } 1394 } 1395 else { 1396 // All of n's children have been processed, complete post-processing. 1397 if (cnt != 0 && !n->is_Con()) { 1398 assert(has_node(n), "no dead nodes"); 1399 split_if_with_blocks_post( n ); 1400 } 1401 if (nstack.is_empty()) { 1402 // Finished all nodes on stack. 1403 break; 1404 } 1405 // Get saved parent node and next use's index. Visit the rest of uses. 1406 n = nstack.node(); 1407 cnt = n->outcnt(); 1408 i = nstack.index(); 1409 nstack.pop(); 1410 } 1411 } 1412 } 1413 1414 1415 //============================================================================= 1416 // 1417 // C L O N E A L O O P B O D Y 1418 // 1419 1420 //------------------------------clone_iff-------------------------------------- 1421 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 1422 // "Nearly" because all Nodes have been cloned from the original in the loop, 1423 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 1424 // through the Phi recursively, and return a Bool. 1425 Node* PhaseIdealLoop::clone_iff(PhiNode *phi, IdealLoopTree *loop) { 1426 1427 // Convert this Phi into a Phi merging Bools 1428 uint i; 1429 for (i = 1; i < phi->req(); i++) { 1430 Node *b = phi->in(i); 1431 if (b->is_Phi()) { 1432 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi(), loop)); 1433 } else { 1434 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, ""); 1435 } 1436 } 1437 1438 Node* n = phi->in(1); 1439 Node* sample_opaque = NULL; 1440 Node *sample_bool = NULL; 1441 if (n->Opcode() == Op_Opaque4) { 1442 sample_opaque = n; 1443 sample_bool = n->in(1); 1444 assert(sample_bool->is_Bool(), "wrong type"); 1445 } else { 1446 sample_bool = n; 1447 } 1448 Node *sample_cmp = sample_bool->in(1); 1449 1450 // Make Phis to merge the Cmp's inputs. 1451 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP); 1452 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP); 1453 for (i = 1; i < phi->req(); i++) { 1454 Node *n1 = sample_opaque == NULL ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1); 1455 Node *n2 = sample_opaque == NULL ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2); 1456 phi1->set_req(i, n1); 1457 phi2->set_req(i, n2); 1458 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); 1459 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); 1460 } 1461 // See if these Phis have been made before. 1462 // Register with optimizer 1463 Node *hit1 = _igvn.hash_find_insert(phi1); 1464 if (hit1) { // Hit, toss just made Phi 1465 _igvn.remove_dead_node(phi1); // Remove new phi 1466 assert(hit1->is_Phi(), "" ); 1467 phi1 = (PhiNode*)hit1; // Use existing phi 1468 } else { // Miss 1469 _igvn.register_new_node_with_optimizer(phi1); 1470 } 1471 Node *hit2 = _igvn.hash_find_insert(phi2); 1472 if (hit2) { // Hit, toss just made Phi 1473 _igvn.remove_dead_node(phi2); // Remove new phi 1474 assert(hit2->is_Phi(), "" ); 1475 phi2 = (PhiNode*)hit2; // Use existing phi 1476 } else { // Miss 1477 _igvn.register_new_node_with_optimizer(phi2); 1478 } 1479 // Register Phis with loop/block info 1480 set_ctrl(phi1, phi->in(0)); 1481 set_ctrl(phi2, phi->in(0)); 1482 // Make a new Cmp 1483 Node *cmp = sample_cmp->clone(); 1484 cmp->set_req(1, phi1); 1485 cmp->set_req(2, phi2); 1486 _igvn.register_new_node_with_optimizer(cmp); 1487 set_ctrl(cmp, phi->in(0)); 1488 1489 // Make a new Bool 1490 Node *b = sample_bool->clone(); 1491 b->set_req(1,cmp); 1492 _igvn.register_new_node_with_optimizer(b); 1493 set_ctrl(b, phi->in(0)); 1494 1495 if (sample_opaque != NULL) { 1496 Node* opaque = sample_opaque->clone(); 1497 opaque->set_req(1, b); 1498 _igvn.register_new_node_with_optimizer(opaque); 1499 set_ctrl(opaque, phi->in(0)); 1500 return opaque; 1501 } 1502 1503 assert(b->is_Bool(), ""); 1504 return b; 1505 } 1506 1507 //------------------------------clone_bool------------------------------------- 1508 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 1509 // "Nearly" because all Nodes have been cloned from the original in the loop, 1510 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 1511 // through the Phi recursively, and return a Bool. 1512 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { 1513 uint i; 1514 // Convert this Phi into a Phi merging Bools 1515 for( i = 1; i < phi->req(); i++ ) { 1516 Node *b = phi->in(i); 1517 if( b->is_Phi() ) { 1518 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop )); 1519 } else { 1520 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); 1521 } 1522 } 1523 1524 Node *sample_cmp = phi->in(1); 1525 1526 // Make Phis to merge the Cmp's inputs. 1527 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP ); 1528 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP ); 1529 for( uint j = 1; j < phi->req(); j++ ) { 1530 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP 1531 Node *n1, *n2; 1532 if( cmp_top->is_Cmp() ) { 1533 n1 = cmp_top->in(1); 1534 n2 = cmp_top->in(2); 1535 } else { 1536 n1 = n2 = cmp_top; 1537 } 1538 phi1->set_req( j, n1 ); 1539 phi2->set_req( j, n2 ); 1540 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); 1541 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); 1542 } 1543 1544 // See if these Phis have been made before. 1545 // Register with optimizer 1546 Node *hit1 = _igvn.hash_find_insert(phi1); 1547 if( hit1 ) { // Hit, toss just made Phi 1548 _igvn.remove_dead_node(phi1); // Remove new phi 1549 assert( hit1->is_Phi(), "" ); 1550 phi1 = (PhiNode*)hit1; // Use existing phi 1551 } else { // Miss 1552 _igvn.register_new_node_with_optimizer(phi1); 1553 } 1554 Node *hit2 = _igvn.hash_find_insert(phi2); 1555 if( hit2 ) { // Hit, toss just made Phi 1556 _igvn.remove_dead_node(phi2); // Remove new phi 1557 assert( hit2->is_Phi(), "" ); 1558 phi2 = (PhiNode*)hit2; // Use existing phi 1559 } else { // Miss 1560 _igvn.register_new_node_with_optimizer(phi2); 1561 } 1562 // Register Phis with loop/block info 1563 set_ctrl(phi1, phi->in(0)); 1564 set_ctrl(phi2, phi->in(0)); 1565 // Make a new Cmp 1566 Node *cmp = sample_cmp->clone(); 1567 cmp->set_req( 1, phi1 ); 1568 cmp->set_req( 2, phi2 ); 1569 _igvn.register_new_node_with_optimizer(cmp); 1570 set_ctrl(cmp, phi->in(0)); 1571 1572 assert( cmp->is_Cmp(), "" ); 1573 return (CmpNode*)cmp; 1574 } 1575 1576 //------------------------------sink_use--------------------------------------- 1577 // If 'use' was in the loop-exit block, it now needs to be sunk 1578 // below the post-loop merge point. 1579 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { 1580 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { 1581 set_ctrl(use, post_loop); 1582 for (DUIterator j = use->outs(); use->has_out(j); j++) 1583 sink_use(use->out(j), post_loop); 1584 } 1585 } 1586 1587 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new, 1588 IdealLoopTree* loop, IdealLoopTree* outer_loop, 1589 Node_List*& split_if_set, Node_List*& split_bool_set, 1590 Node_List*& split_cex_set, Node_List& worklist, 1591 uint new_counter, CloneLoopMode mode) { 1592 Node* nnn = old_new[old->_idx]; 1593 // Copy uses to a worklist, so I can munge the def-use info 1594 // with impunity. 1595 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) 1596 worklist.push(old->fast_out(j)); 1597 1598 while( worklist.size() ) { 1599 Node *use = worklist.pop(); 1600 if (!has_node(use)) continue; // Ignore dead nodes 1601 if (use->in(0) == C->top()) continue; 1602 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); 1603 // Check for data-use outside of loop - at least one of OLD or USE 1604 // must not be a CFG node. 1605 #ifdef ASSERT 1606 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == NULL) { 1607 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint(); 1608 assert(mode == ControlAroundStripMined && use == sfpt, "missed a node"); 1609 } 1610 #endif 1611 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) { 1612 1613 // If the Data use is an IF, that means we have an IF outside of the 1614 // loop that is switching on a condition that is set inside of the 1615 // loop. Happens if people set a loop-exit flag; then test the flag 1616 // in the loop to break the loop, then test is again outside of the 1617 // loop to determine which way the loop exited. 1618 // Loop predicate If node connects to Bool node through Opaque1 node. 1619 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use) || use->Opcode() == Op_Opaque4) { 1620 // Since this code is highly unlikely, we lazily build the worklist 1621 // of such Nodes to go split. 1622 if (!split_if_set) { 1623 ResourceArea *area = Thread::current()->resource_area(); 1624 split_if_set = new Node_List(area); 1625 } 1626 split_if_set->push(use); 1627 } 1628 if (use->is_Bool()) { 1629 if (!split_bool_set) { 1630 ResourceArea *area = Thread::current()->resource_area(); 1631 split_bool_set = new Node_List(area); 1632 } 1633 split_bool_set->push(use); 1634 } 1635 if (use->Opcode() == Op_CreateEx) { 1636 if (!split_cex_set) { 1637 ResourceArea *area = Thread::current()->resource_area(); 1638 split_cex_set = new Node_List(area); 1639 } 1640 split_cex_set->push(use); 1641 } 1642 1643 1644 // Get "block" use is in 1645 uint idx = 0; 1646 while( use->in(idx) != old ) idx++; 1647 Node *prev = use->is_CFG() ? use : get_ctrl(use); 1648 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" ); 1649 Node *cfg = prev->_idx >= new_counter 1650 ? prev->in(2) 1651 : idom(prev); 1652 if( use->is_Phi() ) // Phi use is in prior block 1653 cfg = prev->in(idx); // NOT in block of Phi itself 1654 if (cfg->is_top()) { // Use is dead? 1655 _igvn.replace_input_of(use, idx, C->top()); 1656 continue; 1657 } 1658 1659 while(!outer_loop->is_member(get_loop(cfg))) { 1660 prev = cfg; 1661 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); 1662 } 1663 // If the use occurs after merging several exits from the loop, then 1664 // old value must have dominated all those exits. Since the same old 1665 // value was used on all those exits we did not need a Phi at this 1666 // merge point. NOW we do need a Phi here. Each loop exit value 1667 // is now merged with the peeled body exit; each exit gets its own 1668 // private Phi and those Phis need to be merged here. 1669 Node *phi; 1670 if( prev->is_Region() ) { 1671 if( idx == 0 ) { // Updating control edge? 1672 phi = prev; // Just use existing control 1673 } else { // Else need a new Phi 1674 phi = PhiNode::make( prev, old ); 1675 // Now recursively fix up the new uses of old! 1676 for( uint i = 1; i < prev->req(); i++ ) { 1677 worklist.push(phi); // Onto worklist once for each 'old' input 1678 } 1679 } 1680 } else { 1681 // Get new RegionNode merging old and new loop exits 1682 prev = old_new[prev->_idx]; 1683 assert( prev, "just made this in step 7" ); 1684 if( idx == 0) { // Updating control edge? 1685 phi = prev; // Just use existing control 1686 } else { // Else need a new Phi 1687 // Make a new Phi merging data values properly 1688 phi = PhiNode::make( prev, old ); 1689 phi->set_req( 1, nnn ); 1690 } 1691 } 1692 // If inserting a new Phi, check for prior hits 1693 if( idx != 0 ) { 1694 Node *hit = _igvn.hash_find_insert(phi); 1695 if( hit == NULL ) { 1696 _igvn.register_new_node_with_optimizer(phi); // Register new phi 1697 } else { // or 1698 // Remove the new phi from the graph and use the hit 1699 _igvn.remove_dead_node(phi); 1700 phi = hit; // Use existing phi 1701 } 1702 set_ctrl(phi, prev); 1703 } 1704 // Make 'use' use the Phi instead of the old loop body exit value 1705 _igvn.replace_input_of(use, idx, phi); 1706 if( use->_idx >= new_counter ) { // If updating new phis 1707 // Not needed for correctness, but prevents a weak assert 1708 // in AddPNode from tripping (when we end up with different 1709 // base & derived Phis that will become the same after 1710 // IGVN does CSE). 1711 Node *hit = _igvn.hash_find_insert(use); 1712 if( hit ) // Go ahead and re-hash for hits. 1713 _igvn.replace_node( use, hit ); 1714 } 1715 1716 // If 'use' was in the loop-exit block, it now needs to be sunk 1717 // below the post-loop merge point. 1718 sink_use( use, prev ); 1719 } 1720 } 1721 } 1722 1723 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop, 1724 IdealLoopTree* outer_loop, int dd, Node_List &old_new, 1725 Node_List& extra_data_nodes) { 1726 if (head->is_strip_mined() && mode != IgnoreStripMined) { 1727 CountedLoopNode* cl = head->as_CountedLoop(); 1728 Node* l = cl->outer_loop(); 1729 Node* tail = cl->outer_loop_tail(); 1730 IfNode* le = cl->outer_loop_end(); 1731 Node* sfpt = cl->outer_safepoint(); 1732 CountedLoopEndNode* cle = cl->loopexit(); 1733 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop(); 1734 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit(); 1735 Node* cle_out = cle->proj_out(false); 1736 1737 Node* new_sfpt = NULL; 1738 Node* new_cle_out = cle_out->clone(); 1739 old_new.map(cle_out->_idx, new_cle_out); 1740 if (mode == CloneIncludesStripMined) { 1741 // clone outer loop body 1742 Node* new_l = l->clone(); 1743 Node* new_tail = tail->clone(); 1744 IfNode* new_le = le->clone()->as_If(); 1745 new_sfpt = sfpt->clone(); 1746 1747 set_loop(new_l, outer_loop->_parent); 1748 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd); 1749 set_loop(new_cle_out, outer_loop->_parent); 1750 set_idom(new_cle_out, new_cle, dd); 1751 set_loop(new_sfpt, outer_loop->_parent); 1752 set_idom(new_sfpt, new_cle_out, dd); 1753 set_loop(new_le, outer_loop->_parent); 1754 set_idom(new_le, new_sfpt, dd); 1755 set_loop(new_tail, outer_loop->_parent); 1756 set_idom(new_tail, new_le, dd); 1757 set_idom(new_cl, new_l, dd); 1758 1759 old_new.map(l->_idx, new_l); 1760 old_new.map(tail->_idx, new_tail); 1761 old_new.map(le->_idx, new_le); 1762 old_new.map(sfpt->_idx, new_sfpt); 1763 1764 new_l->set_req(LoopNode::LoopBackControl, new_tail); 1765 new_l->set_req(0, new_l); 1766 new_tail->set_req(0, new_le); 1767 new_le->set_req(0, new_sfpt); 1768 new_sfpt->set_req(0, new_cle_out); 1769 new_cle_out->set_req(0, new_cle); 1770 new_cl->set_req(LoopNode::EntryControl, new_l); 1771 1772 _igvn.register_new_node_with_optimizer(new_l); 1773 _igvn.register_new_node_with_optimizer(new_tail); 1774 _igvn.register_new_node_with_optimizer(new_le); 1775 } else { 1776 Node *newhead = old_new[loop->_head->_idx]; 1777 newhead->as_Loop()->clear_strip_mined(); 1778 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl)); 1779 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); 1780 } 1781 // Look at data node that were assigned a control in the outer 1782 // loop: they are kept in the outer loop by the safepoint so start 1783 // from the safepoint node's inputs. 1784 IdealLoopTree* outer_loop = get_loop(l); 1785 Node_Stack stack(2); 1786 stack.push(sfpt, 1); 1787 uint new_counter = C->unique(); 1788 while (stack.size() > 0) { 1789 Node* n = stack.node(); 1790 uint i = stack.index(); 1791 while (i < n->req() && 1792 (n->in(i) == NULL || 1793 !has_ctrl(n->in(i)) || 1794 get_loop(get_ctrl(n->in(i))) != outer_loop || 1795 (old_new[n->in(i)->_idx] != NULL && old_new[n->in(i)->_idx]->_idx >= new_counter))) { 1796 i++; 1797 } 1798 if (i < n->req()) { 1799 stack.set_index(i+1); 1800 stack.push(n->in(i), 0); 1801 } else { 1802 assert(old_new[n->_idx] == NULL || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet"); 1803 Node* m = n == sfpt ? new_sfpt : n->clone(); 1804 if (m != NULL) { 1805 for (uint i = 0; i < n->req(); i++) { 1806 if (m->in(i) != NULL && old_new[m->in(i)->_idx] != NULL) { 1807 m->set_req(i, old_new[m->in(i)->_idx]); 1808 } 1809 } 1810 } else { 1811 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?"); 1812 } 1813 if (n != sfpt) { 1814 extra_data_nodes.push(n); 1815 _igvn.register_new_node_with_optimizer(m); 1816 assert(get_ctrl(n) == cle_out, "what other control?"); 1817 set_ctrl(m, new_cle_out); 1818 old_new.map(n->_idx, m); 1819 } 1820 stack.pop(); 1821 } 1822 } 1823 if (mode == CloneIncludesStripMined) { 1824 _igvn.register_new_node_with_optimizer(new_sfpt); 1825 _igvn.register_new_node_with_optimizer(new_cle_out); 1826 } 1827 } else { 1828 Node *newhead = old_new[loop->_head->_idx]; 1829 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); 1830 } 1831 } 1832 1833 //------------------------------clone_loop------------------------------------- 1834 // 1835 // C L O N E A L O O P B O D Y 1836 // 1837 // This is the basic building block of the loop optimizations. It clones an 1838 // entire loop body. It makes an old_new loop body mapping; with this mapping 1839 // you can find the new-loop equivalent to an old-loop node. All new-loop 1840 // nodes are exactly equal to their old-loop counterparts, all edges are the 1841 // same. All exits from the old-loop now have a RegionNode that merges the 1842 // equivalent new-loop path. This is true even for the normal "loop-exit" 1843 // condition. All uses of loop-invariant old-loop values now come from (one 1844 // or more) Phis that merge their new-loop equivalents. 1845 // 1846 // This operation leaves the graph in an illegal state: there are two valid 1847 // control edges coming from the loop pre-header to both loop bodies. I'll 1848 // definitely have to hack the graph after running this transform. 1849 // 1850 // From this building block I will further edit edges to perform loop peeling 1851 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. 1852 // 1853 // Parameter side_by_size_idom: 1854 // When side_by_size_idom is NULL, the dominator tree is constructed for 1855 // the clone loop to dominate the original. Used in construction of 1856 // pre-main-post loop sequence. 1857 // When nonnull, the clone and original are side-by-side, both are 1858 // dominated by the side_by_side_idom node. Used in construction of 1859 // unswitched loops. 1860 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, 1861 CloneLoopMode mode, Node* side_by_side_idom) { 1862 1863 LoopNode* head = loop->_head->as_Loop(); 1864 head->verify_strip_mined(1); 1865 1866 if (C->do_vector_loop() && PrintOpto) { 1867 const char* mname = C->method()->name()->as_quoted_ascii(); 1868 if (mname != NULL) { 1869 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname); 1870 } 1871 } 1872 1873 CloneMap& cm = C->clone_map(); 1874 Dict* dict = cm.dict(); 1875 if (C->do_vector_loop()) { 1876 cm.set_clone_idx(cm.max_gen()+1); 1877 #ifndef PRODUCT 1878 if (PrintOpto) { 1879 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx()); 1880 loop->dump_head(); 1881 } 1882 #endif 1883 } 1884 1885 // Step 1: Clone the loop body. Make the old->new mapping. 1886 uint i; 1887 for( i = 0; i < loop->_body.size(); i++ ) { 1888 Node *old = loop->_body.at(i); 1889 Node *nnn = old->clone(); 1890 old_new.map( old->_idx, nnn ); 1891 if (C->do_vector_loop()) { 1892 cm.verify_insert_and_clone(old, nnn, cm.clone_idx()); 1893 } 1894 _igvn.register_new_node_with_optimizer(nnn); 1895 } 1896 1897 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop; 1898 1899 // Step 2: Fix the edges in the new body. If the old input is outside the 1900 // loop use it. If the old input is INside the loop, use the corresponding 1901 // new node instead. 1902 for( i = 0; i < loop->_body.size(); i++ ) { 1903 Node *old = loop->_body.at(i); 1904 Node *nnn = old_new[old->_idx]; 1905 // Fix CFG/Loop controlling the new node 1906 if (has_ctrl(old)) { 1907 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); 1908 } else { 1909 set_loop(nnn, outer_loop->_parent); 1910 if (old->outcnt() > 0) { 1911 set_idom( nnn, old_new[idom(old)->_idx], dd ); 1912 } 1913 } 1914 // Correct edges to the new node 1915 for( uint j = 0; j < nnn->req(); j++ ) { 1916 Node *n = nnn->in(j); 1917 if( n ) { 1918 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); 1919 if( loop->is_member( old_in_loop ) ) 1920 nnn->set_req(j, old_new[n->_idx]); 1921 } 1922 } 1923 _igvn.hash_find_insert(nnn); 1924 } 1925 1926 ResourceArea *area = Thread::current()->resource_area(); 1927 Node_List extra_data_nodes(area); 1928 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes); 1929 1930 // Step 3: Now fix control uses. Loop varying control uses have already 1931 // been fixed up (as part of all input edges in Step 2). Loop invariant 1932 // control uses must be either an IfFalse or an IfTrue. Make a merge 1933 // point to merge the old and new IfFalse/IfTrue nodes; make the use 1934 // refer to this. 1935 Node_List worklist(area); 1936 uint new_counter = C->unique(); 1937 for( i = 0; i < loop->_body.size(); i++ ) { 1938 Node* old = loop->_body.at(i); 1939 if( !old->is_CFG() ) continue; 1940 1941 // Copy uses to a worklist, so I can munge the def-use info 1942 // with impunity. 1943 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) 1944 worklist.push(old->fast_out(j)); 1945 1946 while( worklist.size() ) { // Visit all uses 1947 Node *use = worklist.pop(); 1948 if (!has_node(use)) continue; // Ignore dead nodes 1949 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); 1950 if( !loop->is_member( use_loop ) && use->is_CFG() ) { 1951 // Both OLD and USE are CFG nodes here. 1952 assert( use->is_Proj(), "" ); 1953 Node* nnn = old_new[old->_idx]; 1954 1955 Node* newuse = NULL; 1956 if (head->is_strip_mined() && mode != IgnoreStripMined) { 1957 CountedLoopNode* cl = head->as_CountedLoop(); 1958 CountedLoopEndNode* cle = cl->loopexit(); 1959 Node* cle_out = cle->proj_out_or_null(false); 1960 if (use == cle_out) { 1961 IfNode* le = cl->outer_loop_end(); 1962 use = le->proj_out(false); 1963 use_loop = get_loop(use); 1964 if (mode == CloneIncludesStripMined) { 1965 nnn = old_new[le->_idx]; 1966 } else { 1967 newuse = old_new[cle_out->_idx]; 1968 } 1969 } 1970 } 1971 if (newuse == NULL) { 1972 newuse = use->clone(); 1973 } 1974 1975 // Clone the loop exit control projection 1976 if (C->do_vector_loop()) { 1977 cm.verify_insert_and_clone(use, newuse, cm.clone_idx()); 1978 } 1979 newuse->set_req(0,nnn); 1980 _igvn.register_new_node_with_optimizer(newuse); 1981 set_loop(newuse, use_loop); 1982 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); 1983 1984 // We need a Region to merge the exit from the peeled body and the 1985 // exit from the old loop body. 1986 RegionNode *r = new RegionNode(3); 1987 // Map the old use to the new merge point 1988 old_new.map( use->_idx, r ); 1989 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); 1990 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); 1991 1992 // The original user of 'use' uses 'r' instead. 1993 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { 1994 Node* useuse = use->last_out(l); 1995 _igvn.rehash_node_delayed(useuse); 1996 uint uses_found = 0; 1997 if( useuse->in(0) == use ) { 1998 useuse->set_req(0, r); 1999 uses_found++; 2000 if( useuse->is_CFG() ) { 2001 assert( dom_depth(useuse) > dd_r, "" ); 2002 set_idom(useuse, r, dom_depth(useuse)); 2003 } 2004 } 2005 for( uint k = 1; k < useuse->req(); k++ ) { 2006 if( useuse->in(k) == use ) { 2007 useuse->set_req(k, r); 2008 uses_found++; 2009 if (useuse->is_Loop() && k == LoopNode::EntryControl) { 2010 assert(dom_depth(useuse) > dd_r , ""); 2011 set_idom(useuse, r, dom_depth(useuse)); 2012 } 2013 } 2014 } 2015 l -= uses_found; // we deleted 1 or more copies of this edge 2016 } 2017 2018 // Now finish up 'r' 2019 r->set_req( 1, newuse ); 2020 r->set_req( 2, use ); 2021 _igvn.register_new_node_with_optimizer(r); 2022 set_loop(r, use_loop); 2023 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); 2024 } // End of if a loop-exit test 2025 } 2026 } 2027 2028 // Step 4: If loop-invariant use is not control, it must be dominated by a 2029 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region 2030 // there if needed. Make a Phi there merging old and new used values. 2031 Node_List *split_if_set = NULL; 2032 Node_List *split_bool_set = NULL; 2033 Node_List *split_cex_set = NULL; 2034 for( i = 0; i < loop->_body.size(); i++ ) { 2035 Node* old = loop->_body.at(i); 2036 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set, 2037 split_bool_set, split_cex_set, worklist, new_counter, 2038 mode); 2039 } 2040 2041 for (i = 0; i < extra_data_nodes.size(); i++) { 2042 Node* old = extra_data_nodes.at(i); 2043 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set, 2044 split_bool_set, split_cex_set, worklist, new_counter, 2045 mode); 2046 } 2047 2048 // Check for IFs that need splitting/cloning. Happens if an IF outside of 2049 // the loop uses a condition set in the loop. The original IF probably 2050 // takes control from one or more OLD Regions (which in turn get from NEW 2051 // Regions). In any case, there will be a set of Phis for each merge point 2052 // from the IF up to where the original BOOL def exists the loop. 2053 if (split_if_set) { 2054 while (split_if_set->size()) { 2055 Node *iff = split_if_set->pop(); 2056 if (iff->in(1)->is_Phi()) { 2057 Node *b = clone_iff(iff->in(1)->as_Phi(), loop); 2058 _igvn.replace_input_of(iff, 1, b); 2059 } 2060 } 2061 } 2062 if (split_bool_set) { 2063 while (split_bool_set->size()) { 2064 Node *b = split_bool_set->pop(); 2065 Node *phi = b->in(1); 2066 assert(phi->is_Phi(), ""); 2067 CmpNode *cmp = clone_bool((PhiNode*)phi, loop); 2068 _igvn.replace_input_of(b, 1, cmp); 2069 } 2070 } 2071 if (split_cex_set) { 2072 while (split_cex_set->size()) { 2073 Node *b = split_cex_set->pop(); 2074 assert(b->in(0)->is_Region(), ""); 2075 assert(b->in(1)->is_Phi(), ""); 2076 assert(b->in(0)->in(0) == b->in(1)->in(0), ""); 2077 split_up(b, b->in(0), NULL); 2078 } 2079 } 2080 2081 } 2082 2083 2084 //---------------------- stride_of_possible_iv ------------------------------------- 2085 // Looks for an iff/bool/comp with one operand of the compare 2086 // being a cycle involving an add and a phi, 2087 // with an optional truncation (left-shift followed by a right-shift) 2088 // of the add. Returns zero if not an iv. 2089 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { 2090 Node* trunc1 = NULL; 2091 Node* trunc2 = NULL; 2092 const TypeInt* ttype = NULL; 2093 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { 2094 return 0; 2095 } 2096 BoolNode* bl = iff->in(1)->as_Bool(); 2097 Node* cmp = bl->in(1); 2098 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) { 2099 return 0; 2100 } 2101 // Must have an invariant operand 2102 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { 2103 return 0; 2104 } 2105 Node* add2 = NULL; 2106 Node* cmp1 = cmp->in(1); 2107 if (cmp1->is_Phi()) { 2108 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) 2109 Node* phi = cmp1; 2110 for (uint i = 1; i < phi->req(); i++) { 2111 Node* in = phi->in(i); 2112 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, 2113 &trunc1, &trunc2, &ttype); 2114 if (add && add->in(1) == phi) { 2115 add2 = add->in(2); 2116 break; 2117 } 2118 } 2119 } else { 2120 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) 2121 Node* addtrunc = cmp1; 2122 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, 2123 &trunc1, &trunc2, &ttype); 2124 if (add && add->in(1)->is_Phi()) { 2125 Node* phi = add->in(1); 2126 for (uint i = 1; i < phi->req(); i++) { 2127 if (phi->in(i) == addtrunc) { 2128 add2 = add->in(2); 2129 break; 2130 } 2131 } 2132 } 2133 } 2134 if (add2 != NULL) { 2135 const TypeInt* add2t = _igvn.type(add2)->is_int(); 2136 if (add2t->is_con()) { 2137 return add2t->get_con(); 2138 } 2139 } 2140 return 0; 2141 } 2142 2143 2144 //---------------------- stay_in_loop ------------------------------------- 2145 // Return the (unique) control output node that's in the loop (if it exists.) 2146 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { 2147 Node* unique = NULL; 2148 if (!n) return NULL; 2149 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 2150 Node* use = n->fast_out(i); 2151 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { 2152 if (unique != NULL) { 2153 return NULL; 2154 } 2155 unique = use; 2156 } 2157 } 2158 return unique; 2159 } 2160 2161 //------------------------------ register_node ------------------------------------- 2162 // Utility to register node "n" with PhaseIdealLoop 2163 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { 2164 _igvn.register_new_node_with_optimizer(n); 2165 loop->_body.push(n); 2166 if (n->is_CFG()) { 2167 set_loop(n, loop); 2168 set_idom(n, pred, ddepth); 2169 } else { 2170 set_ctrl(n, pred); 2171 } 2172 } 2173 2174 //------------------------------ proj_clone ------------------------------------- 2175 // Utility to create an if-projection 2176 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { 2177 ProjNode* c = p->clone()->as_Proj(); 2178 c->set_req(0, iff); 2179 return c; 2180 } 2181 2182 //------------------------------ short_circuit_if ------------------------------------- 2183 // Force the iff control output to be the live_proj 2184 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { 2185 guarantee(live_proj != NULL, "null projection"); 2186 int proj_con = live_proj->_con; 2187 assert(proj_con == 0 || proj_con == 1, "false or true projection"); 2188 Node *con = _igvn.intcon(proj_con); 2189 set_ctrl(con, C->root()); 2190 if (iff) { 2191 iff->set_req(1, con); 2192 } 2193 return con; 2194 } 2195 2196 //------------------------------ insert_if_before_proj ------------------------------------- 2197 // Insert a new if before an if projection (* - new node) 2198 // 2199 // before 2200 // if(test) 2201 // / \ 2202 // v v 2203 // other-proj proj (arg) 2204 // 2205 // after 2206 // if(test) 2207 // / \ 2208 // / v 2209 // | * proj-clone 2210 // v | 2211 // other-proj v 2212 // * new_if(relop(cmp[IU](left,right))) 2213 // / \ 2214 // v v 2215 // * new-proj proj 2216 // (returned) 2217 // 2218 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { 2219 IfNode* iff = proj->in(0)->as_If(); 2220 IdealLoopTree *loop = get_loop(proj); 2221 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 2222 int ddepth = dom_depth(proj); 2223 2224 _igvn.rehash_node_delayed(iff); 2225 _igvn.rehash_node_delayed(proj); 2226 2227 proj->set_req(0, NULL); // temporary disconnect 2228 ProjNode* proj2 = proj_clone(proj, iff); 2229 register_node(proj2, loop, iff, ddepth); 2230 2231 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right); 2232 register_node(cmp, loop, proj2, ddepth); 2233 2234 BoolNode* bol = new BoolNode(cmp, relop); 2235 register_node(bol, loop, proj2, ddepth); 2236 2237 int opcode = iff->Opcode(); 2238 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode"); 2239 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt): 2240 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt); 2241 register_node(new_if, loop, proj2, ddepth); 2242 2243 proj->set_req(0, new_if); // reattach 2244 set_idom(proj, new_if, ddepth); 2245 2246 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); 2247 guarantee(new_exit != NULL, "null exit node"); 2248 register_node(new_exit, get_loop(other_proj), new_if, ddepth); 2249 2250 return new_exit; 2251 } 2252 2253 //------------------------------ insert_region_before_proj ------------------------------------- 2254 // Insert a region before an if projection (* - new node) 2255 // 2256 // before 2257 // if(test) 2258 // / | 2259 // v | 2260 // proj v 2261 // other-proj 2262 // 2263 // after 2264 // if(test) 2265 // / | 2266 // v | 2267 // * proj-clone v 2268 // | other-proj 2269 // v 2270 // * new-region 2271 // | 2272 // v 2273 // * dum_if 2274 // / \ 2275 // v \ 2276 // * dum-proj v 2277 // proj 2278 // 2279 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { 2280 IfNode* iff = proj->in(0)->as_If(); 2281 IdealLoopTree *loop = get_loop(proj); 2282 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); 2283 int ddepth = dom_depth(proj); 2284 2285 _igvn.rehash_node_delayed(iff); 2286 _igvn.rehash_node_delayed(proj); 2287 2288 proj->set_req(0, NULL); // temporary disconnect 2289 ProjNode* proj2 = proj_clone(proj, iff); 2290 register_node(proj2, loop, iff, ddepth); 2291 2292 RegionNode* reg = new RegionNode(2); 2293 reg->set_req(1, proj2); 2294 register_node(reg, loop, iff, ddepth); 2295 2296 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); 2297 register_node(dum_if, loop, reg, ddepth); 2298 2299 proj->set_req(0, dum_if); // reattach 2300 set_idom(proj, dum_if, ddepth); 2301 2302 ProjNode* dum_proj = proj_clone(other_proj, dum_if); 2303 register_node(dum_proj, loop, dum_if, ddepth); 2304 2305 return reg; 2306 } 2307 2308 //------------------------------ insert_cmpi_loop_exit ------------------------------------- 2309 // Clone a signed compare loop exit from an unsigned compare and 2310 // insert it before the unsigned cmp on the stay-in-loop path. 2311 // All new nodes inserted in the dominator tree between the original 2312 // if and it's projections. The original if test is replaced with 2313 // a constant to force the stay-in-loop path. 2314 // 2315 // This is done to make sure that the original if and it's projections 2316 // still dominate the same set of control nodes, that the ctrl() relation 2317 // from data nodes to them is preserved, and that their loop nesting is 2318 // preserved. 2319 // 2320 // before 2321 // if(i <u limit) unsigned compare loop exit 2322 // / | 2323 // v v 2324 // exit-proj stay-in-loop-proj 2325 // 2326 // after 2327 // if(stay-in-loop-const) original if 2328 // / | 2329 // / v 2330 // / if(i < limit) new signed test 2331 // / / | 2332 // / / v 2333 // / / if(i <u limit) new cloned unsigned test 2334 // / / / | 2335 // v v v | 2336 // region | 2337 // | | 2338 // dum-if | 2339 // / | | 2340 // ether | | 2341 // v v 2342 // exit-proj stay-in-loop-proj 2343 // 2344 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { 2345 const bool Signed = true; 2346 const bool Unsigned = false; 2347 2348 BoolNode* bol = if_cmpu->in(1)->as_Bool(); 2349 if (bol->_test._test != BoolTest::lt) return NULL; 2350 CmpNode* cmpu = bol->in(1)->as_Cmp(); 2351 if (cmpu->Opcode() != Op_CmpU) return NULL; 2352 int stride = stride_of_possible_iv(if_cmpu); 2353 if (stride == 0) return NULL; 2354 2355 Node* lp_proj = stay_in_loop(if_cmpu, loop); 2356 guarantee(lp_proj != NULL, "null loop node"); 2357 2358 ProjNode* lp_continue = lp_proj->as_Proj(); 2359 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); 2360 2361 Node* limit = NULL; 2362 if (stride > 0) { 2363 limit = cmpu->in(2); 2364 } else { 2365 limit = _igvn.makecon(TypeInt::ZERO); 2366 set_ctrl(limit, C->root()); 2367 } 2368 // Create a new region on the exit path 2369 RegionNode* reg = insert_region_before_proj(lp_exit); 2370 guarantee(reg != NULL, "null region node"); 2371 2372 // Clone the if-cmpu-true-false using a signed compare 2373 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; 2374 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); 2375 reg->add_req(cmpi_exit); 2376 2377 // Clone the if-cmpu-true-false 2378 BoolTest::mask rel_u = bol->_test._test; 2379 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); 2380 reg->add_req(cmpu_exit); 2381 2382 // Force original if to stay in loop. 2383 short_circuit_if(if_cmpu, lp_continue); 2384 2385 return cmpi_exit->in(0)->as_If(); 2386 } 2387 2388 //------------------------------ remove_cmpi_loop_exit ------------------------------------- 2389 // Remove a previously inserted signed compare loop exit. 2390 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { 2391 Node* lp_proj = stay_in_loop(if_cmp, loop); 2392 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && 2393 stay_in_loop(lp_proj, loop)->is_If() && 2394 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); 2395 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); 2396 set_ctrl(con, C->root()); 2397 if_cmp->set_req(1, con); 2398 } 2399 2400 //------------------------------ scheduled_nodelist ------------------------------------- 2401 // Create a post order schedule of nodes that are in the 2402 // "member" set. The list is returned in "sched". 2403 // The first node in "sched" is the loop head, followed by 2404 // nodes which have no inputs in the "member" set, and then 2405 // followed by the nodes that have an immediate input dependence 2406 // on a node in "sched". 2407 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { 2408 2409 assert(member.test(loop->_head->_idx), "loop head must be in member set"); 2410 Arena *a = Thread::current()->resource_area(); 2411 VectorSet visited(a); 2412 Node_Stack nstack(a, loop->_body.size()); 2413 2414 Node* n = loop->_head; // top of stack is cached in "n" 2415 uint idx = 0; 2416 visited.set(n->_idx); 2417 2418 // Initially push all with no inputs from within member set 2419 for(uint i = 0; i < loop->_body.size(); i++ ) { 2420 Node *elt = loop->_body.at(i); 2421 if (member.test(elt->_idx)) { 2422 bool found = false; 2423 for (uint j = 0; j < elt->req(); j++) { 2424 Node* def = elt->in(j); 2425 if (def && member.test(def->_idx) && def != elt) { 2426 found = true; 2427 break; 2428 } 2429 } 2430 if (!found && elt != loop->_head) { 2431 nstack.push(n, idx); 2432 n = elt; 2433 assert(!visited.test(n->_idx), "not seen yet"); 2434 visited.set(n->_idx); 2435 } 2436 } 2437 } 2438 2439 // traverse out's that are in the member set 2440 while (true) { 2441 if (idx < n->outcnt()) { 2442 Node* use = n->raw_out(idx); 2443 idx++; 2444 if (!visited.test_set(use->_idx)) { 2445 if (member.test(use->_idx)) { 2446 nstack.push(n, idx); 2447 n = use; 2448 idx = 0; 2449 } 2450 } 2451 } else { 2452 // All outputs processed 2453 sched.push(n); 2454 if (nstack.is_empty()) break; 2455 n = nstack.node(); 2456 idx = nstack.index(); 2457 nstack.pop(); 2458 } 2459 } 2460 } 2461 2462 2463 //------------------------------ has_use_in_set ------------------------------------- 2464 // Has a use in the vector set 2465 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { 2466 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2467 Node* use = n->fast_out(j); 2468 if (vset.test(use->_idx)) { 2469 return true; 2470 } 2471 } 2472 return false; 2473 } 2474 2475 2476 //------------------------------ has_use_internal_to_set ------------------------------------- 2477 // Has use internal to the vector set (ie. not in a phi at the loop head) 2478 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { 2479 Node* head = loop->_head; 2480 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2481 Node* use = n->fast_out(j); 2482 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { 2483 return true; 2484 } 2485 } 2486 return false; 2487 } 2488 2489 2490 //------------------------------ clone_for_use_outside_loop ------------------------------------- 2491 // clone "n" for uses that are outside of loop 2492 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { 2493 int cloned = 0; 2494 assert(worklist.size() == 0, "should be empty"); 2495 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2496 Node* use = n->fast_out(j); 2497 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { 2498 worklist.push(use); 2499 } 2500 } 2501 while( worklist.size() ) { 2502 Node *use = worklist.pop(); 2503 if (!has_node(use) || use->in(0) == C->top()) continue; 2504 uint j; 2505 for (j = 0; j < use->req(); j++) { 2506 if (use->in(j) == n) break; 2507 } 2508 assert(j < use->req(), "must be there"); 2509 2510 // clone "n" and insert it between the inputs of "n" and the use outside the loop 2511 Node* n_clone = n->clone(); 2512 _igvn.replace_input_of(use, j, n_clone); 2513 cloned++; 2514 Node* use_c; 2515 if (!use->is_Phi()) { 2516 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); 2517 } else { 2518 // Use in a phi is considered a use in the associated predecessor block 2519 use_c = use->in(0)->in(j); 2520 } 2521 set_ctrl(n_clone, use_c); 2522 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); 2523 get_loop(use_c)->_body.push(n_clone); 2524 _igvn.register_new_node_with_optimizer(n_clone); 2525 #if !defined(PRODUCT) 2526 if (TracePartialPeeling) { 2527 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); 2528 } 2529 #endif 2530 } 2531 return cloned; 2532 } 2533 2534 2535 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- 2536 // clone "n" for special uses that are in the not_peeled region. 2537 // If these def-uses occur in separate blocks, the code generator 2538 // marks the method as not compilable. For example, if a "BoolNode" 2539 // is in a different basic block than the "IfNode" that uses it, then 2540 // the compilation is aborted in the code generator. 2541 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, 2542 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { 2543 if (n->is_Phi() || n->is_Load()) { 2544 return; 2545 } 2546 assert(worklist.size() == 0, "should be empty"); 2547 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 2548 Node* use = n->fast_out(j); 2549 if ( not_peel.test(use->_idx) && 2550 (use->is_If() || use->is_CMove() || use->is_Bool()) && 2551 use->in(1) == n) { 2552 worklist.push(use); 2553 } 2554 } 2555 if (worklist.size() > 0) { 2556 // clone "n" and insert it between inputs of "n" and the use 2557 Node* n_clone = n->clone(); 2558 loop->_body.push(n_clone); 2559 _igvn.register_new_node_with_optimizer(n_clone); 2560 set_ctrl(n_clone, get_ctrl(n)); 2561 sink_list.push(n_clone); 2562 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. 2563 #if !defined(PRODUCT) 2564 if (TracePartialPeeling) { 2565 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); 2566 } 2567 #endif 2568 while( worklist.size() ) { 2569 Node *use = worklist.pop(); 2570 _igvn.rehash_node_delayed(use); 2571 for (uint j = 1; j < use->req(); j++) { 2572 if (use->in(j) == n) { 2573 use->set_req(j, n_clone); 2574 } 2575 } 2576 } 2577 } 2578 } 2579 2580 2581 //------------------------------ insert_phi_for_loop ------------------------------------- 2582 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist 2583 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { 2584 Node *phi = PhiNode::make(lp, back_edge_val); 2585 phi->set_req(LoopNode::EntryControl, lp_entry_val); 2586 // Use existing phi if it already exists 2587 Node *hit = _igvn.hash_find_insert(phi); 2588 if( hit == NULL ) { 2589 _igvn.register_new_node_with_optimizer(phi); 2590 set_ctrl(phi, lp); 2591 } else { 2592 // Remove the new phi from the graph and use the hit 2593 _igvn.remove_dead_node(phi); 2594 phi = hit; 2595 } 2596 _igvn.replace_input_of(use, idx, phi); 2597 } 2598 2599 #ifdef ASSERT 2600 //------------------------------ is_valid_loop_partition ------------------------------------- 2601 // Validate the loop partition sets: peel and not_peel 2602 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, 2603 VectorSet& not_peel ) { 2604 uint i; 2605 // Check that peel_list entries are in the peel set 2606 for (i = 0; i < peel_list.size(); i++) { 2607 if (!peel.test(peel_list.at(i)->_idx)) { 2608 return false; 2609 } 2610 } 2611 // Check at loop members are in one of peel set or not_peel set 2612 for (i = 0; i < loop->_body.size(); i++ ) { 2613 Node *def = loop->_body.at(i); 2614 uint di = def->_idx; 2615 // Check that peel set elements are in peel_list 2616 if (peel.test(di)) { 2617 if (not_peel.test(di)) { 2618 return false; 2619 } 2620 // Must be in peel_list also 2621 bool found = false; 2622 for (uint j = 0; j < peel_list.size(); j++) { 2623 if (peel_list.at(j)->_idx == di) { 2624 found = true; 2625 break; 2626 } 2627 } 2628 if (!found) { 2629 return false; 2630 } 2631 } else if (not_peel.test(di)) { 2632 if (peel.test(di)) { 2633 return false; 2634 } 2635 } else { 2636 return false; 2637 } 2638 } 2639 return true; 2640 } 2641 2642 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- 2643 // Ensure a use outside of loop is of the right form 2644 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { 2645 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 2646 return (use->is_Phi() && 2647 use_c->is_Region() && use_c->req() == 3 && 2648 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || 2649 use_c->in(exit_idx)->Opcode() == Op_IfFalse || 2650 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && 2651 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); 2652 } 2653 2654 //------------------------------ is_valid_clone_loop_form ------------------------------------- 2655 // Ensure that all uses outside of loop are of the right form 2656 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, 2657 uint orig_exit_idx, uint clone_exit_idx) { 2658 uint len = peel_list.size(); 2659 for (uint i = 0; i < len; i++) { 2660 Node *def = peel_list.at(i); 2661 2662 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 2663 Node *use = def->fast_out(j); 2664 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; 2665 if (!loop->is_member(get_loop(use_c))) { 2666 // use is not in the loop, check for correct structure 2667 if (use->in(0) == def) { 2668 // Okay 2669 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { 2670 return false; 2671 } 2672 } 2673 } 2674 } 2675 return true; 2676 } 2677 #endif 2678 2679 //------------------------------ partial_peel ------------------------------------- 2680 // Partially peel (aka loop rotation) the top portion of a loop (called 2681 // the peel section below) by cloning it and placing one copy just before 2682 // the new loop head and the other copy at the bottom of the new loop. 2683 // 2684 // before after where it came from 2685 // 2686 // stmt1 stmt1 2687 // loop: stmt2 clone 2688 // stmt2 if condA goto exitA clone 2689 // if condA goto exitA new_loop: new 2690 // stmt3 stmt3 clone 2691 // if !condB goto loop if condB goto exitB clone 2692 // exitB: stmt2 orig 2693 // stmt4 if !condA goto new_loop orig 2694 // exitA: goto exitA 2695 // exitB: 2696 // stmt4 2697 // exitA: 2698 // 2699 // Step 1: find the cut point: an exit test on probable 2700 // induction variable. 2701 // Step 2: schedule (with cloning) operations in the peel 2702 // section that can be executed after the cut into 2703 // the section that is not peeled. This may need 2704 // to clone operations into exit blocks. For 2705 // instance, a reference to A[i] in the not-peel 2706 // section and a reference to B[i] in an exit block 2707 // may cause a left-shift of i by 2 to be placed 2708 // in the peel block. This step will clone the left 2709 // shift into the exit block and sink the left shift 2710 // from the peel to the not-peel section. 2711 // Step 3: clone the loop, retarget the control, and insert 2712 // phis for values that are live across the new loop 2713 // head. This is very dependent on the graph structure 2714 // from clone_loop. It creates region nodes for 2715 // exit control and associated phi nodes for values 2716 // flow out of the loop through that exit. The region 2717 // node is dominated by the clone's control projection. 2718 // So the clone's peel section is placed before the 2719 // new loop head, and the clone's not-peel section is 2720 // forms the top part of the new loop. The original 2721 // peel section forms the tail of the new loop. 2722 // Step 4: update the dominator tree and recompute the 2723 // dominator depth. 2724 // 2725 // orig 2726 // 2727 // stmt1 2728 // | 2729 // v 2730 // loop predicate 2731 // | 2732 // v 2733 // loop<----+ 2734 // | | 2735 // stmt2 | 2736 // | | 2737 // v | 2738 // ifA | 2739 // / | | 2740 // v v | 2741 // false true ^ <-- last_peel 2742 // / | | 2743 // / ===|==cut | 2744 // / stmt3 | <-- first_not_peel 2745 // / | | 2746 // | v | 2747 // v ifB | 2748 // exitA: / \ | 2749 // / \ | 2750 // v v | 2751 // false true | 2752 // / \ | 2753 // / ----+ 2754 // | 2755 // v 2756 // exitB: 2757 // stmt4 2758 // 2759 // 2760 // after clone loop 2761 // 2762 // stmt1 2763 // | 2764 // v 2765 // loop predicate 2766 // / \ 2767 // clone / \ orig 2768 // / \ 2769 // / \ 2770 // v v 2771 // +---->loop loop<----+ 2772 // | | | | 2773 // | stmt2 stmt2 | 2774 // | | | | 2775 // | v v | 2776 // | ifA ifA | 2777 // | | \ / | | 2778 // | v v v v | 2779 // ^ true false false true ^ <-- last_peel 2780 // | | ^ \ / | | 2781 // | cut==|== \ \ / ===|==cut | 2782 // | stmt3 \ \ / stmt3 | <-- first_not_peel 2783 // | | dom | | | | 2784 // | v \ 1v v2 v | 2785 // | ifB regionA ifB | 2786 // | / \ | / \ | 2787 // | / \ v / \ | 2788 // | v v exitA: v v | 2789 // | true false false true | 2790 // | / ^ \ / \ | 2791 // +---- \ \ / ----+ 2792 // dom \ / 2793 // \ 1v v2 2794 // regionB 2795 // | 2796 // v 2797 // exitB: 2798 // stmt4 2799 // 2800 // 2801 // after partial peel 2802 // 2803 // stmt1 2804 // | 2805 // v 2806 // loop predicate 2807 // / 2808 // clone / orig 2809 // / TOP 2810 // / \ 2811 // v v 2812 // TOP->loop loop----+ 2813 // | | | 2814 // stmt2 stmt2 | 2815 // | | | 2816 // v v | 2817 // ifA ifA | 2818 // | \ / | | 2819 // v v v v | 2820 // true false false true | <-- last_peel 2821 // | ^ \ / +------|---+ 2822 // +->newloop \ \ / === ==cut | | 2823 // | stmt3 \ \ / TOP | | 2824 // | | dom | | stmt3 | | <-- first_not_peel 2825 // | v \ 1v v2 v | | 2826 // | ifB regionA ifB ^ v 2827 // | / \ | / \ | | 2828 // | / \ v / \ | | 2829 // | v v exitA: v v | | 2830 // | true false false true | | 2831 // | / ^ \ / \ | | 2832 // | | \ \ / v | | 2833 // | | dom \ / TOP | | 2834 // | | \ 1v v2 | | 2835 // ^ v regionB | | 2836 // | | | | | 2837 // | | v ^ v 2838 // | | exitB: | | 2839 // | | stmt4 | | 2840 // | +------------>-----------------+ | 2841 // | | 2842 // +-----------------<---------------------+ 2843 // 2844 // 2845 // final graph 2846 // 2847 // stmt1 2848 // | 2849 // v 2850 // loop predicate 2851 // | 2852 // v 2853 // stmt2 clone 2854 // | 2855 // v 2856 // ........> ifA clone 2857 // : / | 2858 // dom / | 2859 // : v v 2860 // : false true 2861 // : | | 2862 // : | v 2863 // : | newloop<-----+ 2864 // : | | | 2865 // : | stmt3 clone | 2866 // : | | | 2867 // : | v | 2868 // : | ifB | 2869 // : | / \ | 2870 // : | v v | 2871 // : | false true | 2872 // : | | | | 2873 // : | v stmt2 | 2874 // : | exitB: | | 2875 // : | stmt4 v | 2876 // : | ifA orig | 2877 // : | / \ | 2878 // : | / \ | 2879 // : | v v | 2880 // : | false true | 2881 // : | / \ | 2882 // : v v -----+ 2883 // RegionA 2884 // | 2885 // v 2886 // exitA 2887 // 2888 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { 2889 2890 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only"); 2891 if (!loop->_head->is_Loop()) { 2892 return false; } 2893 2894 LoopNode *head = loop->_head->as_Loop(); 2895 2896 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { 2897 return false; 2898 } 2899 2900 // Check for complex exit control 2901 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { 2902 Node *n = loop->_body.at(ii); 2903 int opc = n->Opcode(); 2904 if (n->is_Call() || 2905 opc == Op_Catch || 2906 opc == Op_CatchProj || 2907 opc == Op_Jump || 2908 opc == Op_JumpProj) { 2909 #if !defined(PRODUCT) 2910 if (TracePartialPeeling) { 2911 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); 2912 } 2913 #endif 2914 return false; 2915 } 2916 } 2917 2918 int dd = dom_depth(head); 2919 2920 // Step 1: find cut point 2921 2922 // Walk up dominators to loop head looking for first loop exit 2923 // which is executed on every path thru loop. 2924 IfNode *peel_if = NULL; 2925 IfNode *peel_if_cmpu = NULL; 2926 2927 Node *iff = loop->tail(); 2928 while( iff != head ) { 2929 if( iff->is_If() ) { 2930 Node *ctrl = get_ctrl(iff->in(1)); 2931 if (ctrl->is_top()) return false; // Dead test on live IF. 2932 // If loop-varying exit-test, check for induction variable 2933 if( loop->is_member(get_loop(ctrl)) && 2934 loop->is_loop_exit(iff) && 2935 is_possible_iv_test(iff)) { 2936 Node* cmp = iff->in(1)->in(1); 2937 if (cmp->Opcode() == Op_CmpI) { 2938 peel_if = iff->as_If(); 2939 } else { 2940 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); 2941 peel_if_cmpu = iff->as_If(); 2942 } 2943 } 2944 } 2945 iff = idom(iff); 2946 } 2947 // Prefer signed compare over unsigned compare. 2948 IfNode* new_peel_if = NULL; 2949 if (peel_if == NULL) { 2950 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { 2951 return false; // No peel point found 2952 } 2953 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); 2954 if (new_peel_if == NULL) { 2955 return false; // No peel point found 2956 } 2957 peel_if = new_peel_if; 2958 } 2959 Node* last_peel = stay_in_loop(peel_if, loop); 2960 Node* first_not_peeled = stay_in_loop(last_peel, loop); 2961 if (first_not_peeled == NULL || first_not_peeled == head) { 2962 return false; 2963 } 2964 2965 #if !defined(PRODUCT) 2966 if (TraceLoopOpts) { 2967 tty->print("PartialPeel "); 2968 loop->dump_head(); 2969 } 2970 2971 if (TracePartialPeeling) { 2972 tty->print_cr("before partial peel one iteration"); 2973 Node_List wl; 2974 Node* t = head->in(2); 2975 while (true) { 2976 wl.push(t); 2977 if (t == head) break; 2978 t = idom(t); 2979 } 2980 while (wl.size() > 0) { 2981 Node* tt = wl.pop(); 2982 tt->dump(); 2983 if (tt == last_peel) tty->print_cr("-- cut --"); 2984 } 2985 } 2986 #endif 2987 ResourceArea *area = Thread::current()->resource_area(); 2988 VectorSet peel(area); 2989 VectorSet not_peel(area); 2990 Node_List peel_list(area); 2991 Node_List worklist(area); 2992 Node_List sink_list(area); 2993 2994 // Set of cfg nodes to peel are those that are executable from 2995 // the head through last_peel. 2996 assert(worklist.size() == 0, "should be empty"); 2997 worklist.push(head); 2998 peel.set(head->_idx); 2999 while (worklist.size() > 0) { 3000 Node *n = worklist.pop(); 3001 if (n != last_peel) { 3002 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 3003 Node* use = n->fast_out(j); 3004 if (use->is_CFG() && 3005 loop->is_member(get_loop(use)) && 3006 !peel.test_set(use->_idx)) { 3007 worklist.push(use); 3008 } 3009 } 3010 } 3011 } 3012 3013 // Set of non-cfg nodes to peel are those that are control 3014 // dependent on the cfg nodes. 3015 uint i; 3016 for(i = 0; i < loop->_body.size(); i++ ) { 3017 Node *n = loop->_body.at(i); 3018 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; 3019 if (peel.test(n_c->_idx)) { 3020 peel.set(n->_idx); 3021 } else { 3022 not_peel.set(n->_idx); 3023 } 3024 } 3025 3026 // Step 2: move operations from the peeled section down into the 3027 // not-peeled section 3028 3029 // Get a post order schedule of nodes in the peel region 3030 // Result in right-most operand. 3031 scheduled_nodelist(loop, peel, peel_list ); 3032 3033 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 3034 3035 // For future check for too many new phis 3036 uint old_phi_cnt = 0; 3037 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { 3038 Node* use = head->fast_out(j); 3039 if (use->is_Phi()) old_phi_cnt++; 3040 } 3041 3042 #if !defined(PRODUCT) 3043 if (TracePartialPeeling) { 3044 tty->print_cr("\npeeled list"); 3045 } 3046 #endif 3047 3048 // Evacuate nodes in peel region into the not_peeled region if possible 3049 uint new_phi_cnt = 0; 3050 uint cloned_for_outside_use = 0; 3051 for (i = 0; i < peel_list.size();) { 3052 Node* n = peel_list.at(i); 3053 #if !defined(PRODUCT) 3054 if (TracePartialPeeling) n->dump(); 3055 #endif 3056 bool incr = true; 3057 if ( !n->is_CFG() ) { 3058 3059 if ( has_use_in_set(n, not_peel) ) { 3060 3061 // If not used internal to the peeled region, 3062 // move "n" from peeled to not_peeled region. 3063 3064 if ( !has_use_internal_to_set(n, peel, loop) ) { 3065 3066 // if not pinned and not a load (which maybe anti-dependent on a store) 3067 // and not a CMove (Matcher expects only bool->cmove). 3068 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { 3069 cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist ); 3070 sink_list.push(n); 3071 peel >>= n->_idx; // delete n from peel set. 3072 not_peel <<= n->_idx; // add n to not_peel set. 3073 peel_list.remove(i); 3074 incr = false; 3075 #if !defined(PRODUCT) 3076 if (TracePartialPeeling) { 3077 tty->print_cr("sink to not_peeled region: %d newbb: %d", 3078 n->_idx, get_ctrl(n)->_idx); 3079 } 3080 #endif 3081 } 3082 } else { 3083 // Otherwise check for special def-use cases that span 3084 // the peel/not_peel boundary such as bool->if 3085 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); 3086 new_phi_cnt++; 3087 } 3088 } 3089 } 3090 if (incr) i++; 3091 } 3092 3093 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { 3094 #if !defined(PRODUCT) 3095 if (TracePartialPeeling) { 3096 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", 3097 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); 3098 } 3099 #endif 3100 if (new_peel_if != NULL) { 3101 remove_cmpi_loop_exit(new_peel_if, loop); 3102 } 3103 // Inhibit more partial peeling on this loop 3104 assert(!head->is_partial_peel_loop(), "not partial peeled"); 3105 head->mark_partial_peel_failed(); 3106 if (cloned_for_outside_use > 0) { 3107 // Terminate this round of loop opts because 3108 // the graph outside this loop was changed. 3109 C->set_major_progress(); 3110 return true; 3111 } 3112 return false; 3113 } 3114 3115 // Step 3: clone loop, retarget control, and insert new phis 3116 3117 // Create new loop head for new phis and to hang 3118 // the nodes being moved (sinked) from the peel region. 3119 LoopNode* new_head = new LoopNode(last_peel, last_peel); 3120 new_head->set_unswitch_count(head->unswitch_count()); // Preserve 3121 _igvn.register_new_node_with_optimizer(new_head); 3122 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); 3123 _igvn.replace_input_of(first_not_peeled, 0, new_head); 3124 set_loop(new_head, loop); 3125 loop->_body.push(new_head); 3126 not_peel.set(new_head->_idx); 3127 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); 3128 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); 3129 3130 while (sink_list.size() > 0) { 3131 Node* n = sink_list.pop(); 3132 set_ctrl(n, new_head); 3133 } 3134 3135 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); 3136 3137 clone_loop(loop, old_new, dd, IgnoreStripMined); 3138 3139 const uint clone_exit_idx = 1; 3140 const uint orig_exit_idx = 2; 3141 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); 3142 3143 Node* head_clone = old_new[head->_idx]; 3144 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); 3145 Node* orig_tail_clone = head_clone->in(2); 3146 3147 // Add phi if "def" node is in peel set and "use" is not 3148 3149 for(i = 0; i < peel_list.size(); i++ ) { 3150 Node *def = peel_list.at(i); 3151 if (!def->is_CFG()) { 3152 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { 3153 Node *use = def->fast_out(j); 3154 if (has_node(use) && use->in(0) != C->top() && 3155 (!peel.test(use->_idx) || 3156 (use->is_Phi() && use->in(0) == head)) ) { 3157 worklist.push(use); 3158 } 3159 } 3160 while( worklist.size() ) { 3161 Node *use = worklist.pop(); 3162 for (uint j = 1; j < use->req(); j++) { 3163 Node* n = use->in(j); 3164 if (n == def) { 3165 3166 // "def" is in peel set, "use" is not in peel set 3167 // or "use" is in the entry boundary (a phi) of the peel set 3168 3169 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; 3170 3171 if ( loop->is_member(get_loop( use_c )) ) { 3172 // use is in loop 3173 if (old_new[use->_idx] != NULL) { // null for dead code 3174 Node* use_clone = old_new[use->_idx]; 3175 _igvn.replace_input_of(use, j, C->top()); 3176 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); 3177 } 3178 } else { 3179 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); 3180 // use is not in the loop, check if the live range includes the cut 3181 Node* lp_if = use_c->in(orig_exit_idx)->in(0); 3182 if (not_peel.test(lp_if->_idx)) { 3183 assert(j == orig_exit_idx, "use from original loop"); 3184 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); 3185 } 3186 } 3187 } 3188 } 3189 } 3190 } 3191 } 3192 3193 // Step 3b: retarget control 3194 3195 // Redirect control to the new loop head if a cloned node in 3196 // the not_peeled region has control that points into the peeled region. 3197 // This necessary because the cloned peeled region will be outside 3198 // the loop. 3199 // from to 3200 // cloned-peeled <---+ 3201 // new_head_clone: | <--+ 3202 // cloned-not_peeled in(0) in(0) 3203 // orig-peeled 3204 3205 for(i = 0; i < loop->_body.size(); i++ ) { 3206 Node *n = loop->_body.at(i); 3207 if (!n->is_CFG() && n->in(0) != NULL && 3208 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { 3209 Node* n_clone = old_new[n->_idx]; 3210 _igvn.replace_input_of(n_clone, 0, new_head_clone); 3211 } 3212 } 3213 3214 // Backedge of the surviving new_head (the clone) is original last_peel 3215 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel); 3216 3217 // Cut first node in original not_peel set 3218 _igvn.rehash_node_delayed(new_head); // Multiple edge updates: 3219 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of 3220 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls 3221 3222 // Copy head_clone back-branch info to original head 3223 // and remove original head's loop entry and 3224 // clone head's back-branch 3225 _igvn.rehash_node_delayed(head); // Multiple edge updates 3226 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); 3227 head->set_req(LoopNode::LoopBackControl, C->top()); 3228 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top()); 3229 3230 // Similarly modify the phis 3231 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { 3232 Node* use = head->fast_out(k); 3233 if (use->is_Phi() && use->outcnt() > 0) { 3234 Node* use_clone = old_new[use->_idx]; 3235 _igvn.rehash_node_delayed(use); // Multiple edge updates 3236 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); 3237 use->set_req(LoopNode::LoopBackControl, C->top()); 3238 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top()); 3239 } 3240 } 3241 3242 // Step 4: update dominator tree and dominator depth 3243 3244 set_idom(head, orig_tail_clone, dd); 3245 recompute_dom_depth(); 3246 3247 // Inhibit more partial peeling on this loop 3248 new_head_clone->set_partial_peel_loop(); 3249 C->set_major_progress(); 3250 loop->record_for_igvn(); 3251 3252 #if !defined(PRODUCT) 3253 if (TracePartialPeeling) { 3254 tty->print_cr("\nafter partial peel one iteration"); 3255 Node_List wl(area); 3256 Node* t = last_peel; 3257 while (true) { 3258 wl.push(t); 3259 if (t == head_clone) break; 3260 t = idom(t); 3261 } 3262 while (wl.size() > 0) { 3263 Node* tt = wl.pop(); 3264 if (tt == head) tty->print_cr("orig head"); 3265 else if (tt == new_head_clone) tty->print_cr("new head"); 3266 else if (tt == head_clone) tty->print_cr("clone head"); 3267 tt->dump(); 3268 } 3269 } 3270 #endif 3271 return true; 3272 } 3273 3274 //------------------------------reorg_offsets---------------------------------- 3275 // Reorganize offset computations to lower register pressure. Mostly 3276 // prevent loop-fallout uses of the pre-incremented trip counter (which are 3277 // then alive with the post-incremented trip counter forcing an extra 3278 // register move) 3279 void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) { 3280 // Perform it only for canonical counted loops. 3281 // Loop's shape could be messed up by iteration_split_impl. 3282 if (!loop->_head->is_CountedLoop()) 3283 return; 3284 if (!loop->_head->as_Loop()->is_valid_counted_loop()) 3285 return; 3286 3287 CountedLoopNode *cl = loop->_head->as_CountedLoop(); 3288 CountedLoopEndNode *cle = cl->loopexit(); 3289 Node *exit = cle->proj_out(false); 3290 Node *phi = cl->phi(); 3291 3292 // Check for the special case of folks using the pre-incremented 3293 // trip-counter on the fall-out path (forces the pre-incremented 3294 // and post-incremented trip counter to be live at the same time). 3295 // Fix this by adjusting to use the post-increment trip counter. 3296 3297 bool progress = true; 3298 while (progress) { 3299 progress = false; 3300 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { 3301 Node* use = phi->fast_out(i); // User of trip-counter 3302 if (!has_ctrl(use)) continue; 3303 Node *u_ctrl = get_ctrl(use); 3304 if (use->is_Phi()) { 3305 u_ctrl = NULL; 3306 for (uint j = 1; j < use->req(); j++) 3307 if (use->in(j) == phi) 3308 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j)); 3309 } 3310 IdealLoopTree *u_loop = get_loop(u_ctrl); 3311 // Look for loop-invariant use 3312 if (u_loop == loop) continue; 3313 if (loop->is_member(u_loop)) continue; 3314 // Check that use is live out the bottom. Assuming the trip-counter 3315 // update is right at the bottom, uses of of the loop middle are ok. 3316 if (dom_lca(exit, u_ctrl) != exit) continue; 3317 // Hit! Refactor use to use the post-incremented tripcounter. 3318 // Compute a post-increment tripcounter. 3319 Node *opaq = new Opaque2Node( C, cle->incr() ); 3320 register_new_node(opaq, exit); 3321 Node *neg_stride = _igvn.intcon(-cle->stride_con()); 3322 set_ctrl(neg_stride, C->root()); 3323 Node *post = new AddINode( opaq, neg_stride); 3324 register_new_node(post, exit); 3325 _igvn.rehash_node_delayed(use); 3326 for (uint j = 1; j < use->req(); j++) { 3327 if (use->in(j) == phi) 3328 use->set_req(j, post); 3329 } 3330 // Since DU info changed, rerun loop 3331 progress = true; 3332 break; 3333 } 3334 } 3335 3336 }