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comparison: src/share/vm/opto/loopopts.cpp
src/share/vm/opto/loopopts.cpp
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- f90c822e73f8
- child 6876
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| 1 /* | |
| 2 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved. | |
| 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
| 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 20 * or visit www.oracle.com if you need additional information or have any | |
| 21 * questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 #include "precompiled.hpp" | |
| 26 #include "memory/allocation.inline.hpp" | |
| 27 #include "opto/addnode.hpp" | |
| 28 #include "opto/connode.hpp" | |
| 29 #include "opto/divnode.hpp" | |
| 30 #include "opto/loopnode.hpp" | |
| 31 #include "opto/matcher.hpp" | |
| 32 #include "opto/mulnode.hpp" | |
| 33 #include "opto/rootnode.hpp" | |
| 34 #include "opto/subnode.hpp" | |
| 35 | |
| 36 //============================================================================= | |
| 37 //------------------------------split_thru_phi--------------------------------- | |
| 38 // Split Node 'n' through merge point if there is enough win. | |
| 39 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { | |
| 40 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { | |
| 41 // ConvI2L may have type information on it which is unsafe to push up | |
| 42 // so disable this for now | |
| 43 return NULL; | |
| 44 } | |
| 45 | |
| 46 int wins = 0; | |
| 47 assert(!n->is_CFG(), ""); | |
| 48 assert(region->is_Region(), ""); | |
| 49 | |
| 50 const Type* type = n->bottom_type(); | |
| 51 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); | |
| 52 Node *phi; | |
| 53 if (t_oop != NULL && t_oop->is_known_instance_field()) { | |
| 54 int iid = t_oop->instance_id(); | |
| 55 int index = C->get_alias_index(t_oop); | |
| 56 int offset = t_oop->offset(); | |
| 57 phi = new (C) PhiNode(region, type, NULL, iid, index, offset); | |
| 58 } else { | |
| 59 phi = PhiNode::make_blank(region, n); | |
| 60 } | |
| 61 uint old_unique = C->unique(); | |
| 62 for (uint i = 1; i < region->req(); i++) { | |
| 63 Node *x; | |
| 64 Node* the_clone = NULL; | |
| 65 if (region->in(i) == C->top()) { | |
| 66 x = C->top(); // Dead path? Use a dead data op | |
| 67 } else { | |
| 68 x = n->clone(); // Else clone up the data op | |
| 69 the_clone = x; // Remember for possible deletion. | |
| 70 // Alter data node to use pre-phi inputs | |
| 71 if (n->in(0) == region) | |
| 72 x->set_req( 0, region->in(i) ); | |
| 73 for (uint j = 1; j < n->req(); j++) { | |
| 74 Node *in = n->in(j); | |
| 75 if (in->is_Phi() && in->in(0) == region) | |
| 76 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone | |
| 77 } | |
| 78 } | |
| 79 // Check for a 'win' on some paths | |
| 80 const Type *t = x->Value(&_igvn); | |
| 81 | |
| 82 bool singleton = t->singleton(); | |
| 83 | |
| 84 // A TOP singleton indicates that there are no possible values incoming | |
| 85 // along a particular edge. In most cases, this is OK, and the Phi will | |
| 86 // be eliminated later in an Ideal call. However, we can't allow this to | |
| 87 // happen if the singleton occurs on loop entry, as the elimination of | |
| 88 // the PhiNode may cause the resulting node to migrate back to a previous | |
| 89 // loop iteration. | |
| 90 if (singleton && t == Type::TOP) { | |
| 91 // Is_Loop() == false does not confirm the absence of a loop (e.g., an | |
| 92 // irreducible loop may not be indicated by an affirmative is_Loop()); | |
| 93 // therefore, the only top we can split thru a phi is on a backedge of | |
| 94 // a loop. | |
| 95 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); | |
| 96 } | |
| 97 | |
| 98 if (singleton) { | |
| 99 wins++; | |
| 100 x = ((PhaseGVN&)_igvn).makecon(t); | |
| 101 } else { | |
| 102 // We now call Identity to try to simplify the cloned node. | |
| 103 // Note that some Identity methods call phase->type(this). | |
| 104 // Make sure that the type array is big enough for | |
| 105 // our new node, even though we may throw the node away. | |
| 106 // (Note: This tweaking with igvn only works because x is a new node.) | |
| 107 _igvn.set_type(x, t); | |
| 108 // If x is a TypeNode, capture any more-precise type permanently into Node | |
| 109 // otherwise it will be not updated during igvn->transform since | |
| 110 // igvn->type(x) is set to x->Value() already. | |
| 111 x->raise_bottom_type(t); | |
| 112 Node *y = x->Identity(&_igvn); | |
| 113 if (y != x) { | |
| 114 wins++; | |
| 115 x = y; | |
| 116 } else { | |
| 117 y = _igvn.hash_find(x); | |
| 118 if (y) { | |
| 119 wins++; | |
| 120 x = y; | |
| 121 } else { | |
| 122 // Else x is a new node we are keeping | |
| 123 // We do not need register_new_node_with_optimizer | |
| 124 // because set_type has already been called. | |
| 125 _igvn._worklist.push(x); | |
| 126 } | |
| 127 } | |
| 128 } | |
| 129 if (x != the_clone && the_clone != NULL) | |
| 130 _igvn.remove_dead_node(the_clone); | |
| 131 phi->set_req( i, x ); | |
| 132 } | |
| 133 // Too few wins? | |
| 134 if (wins <= policy) { | |
| 135 _igvn.remove_dead_node(phi); | |
| 136 return NULL; | |
| 137 } | |
| 138 | |
| 139 // Record Phi | |
| 140 register_new_node( phi, region ); | |
| 141 | |
| 142 for (uint i2 = 1; i2 < phi->req(); i2++) { | |
| 143 Node *x = phi->in(i2); | |
| 144 // If we commoned up the cloned 'x' with another existing Node, | |
| 145 // the existing Node picks up a new use. We need to make the | |
| 146 // existing Node occur higher up so it dominates its uses. | |
| 147 Node *old_ctrl; | |
| 148 IdealLoopTree *old_loop; | |
| 149 | |
| 150 if (x->is_Con()) { | |
| 151 // Constant's control is always root. | |
| 152 set_ctrl(x, C->root()); | |
| 153 continue; | |
| 154 } | |
| 155 // The occasional new node | |
| 156 if (x->_idx >= old_unique) { // Found a new, unplaced node? | |
| 157 old_ctrl = NULL; | |
| 158 old_loop = NULL; // Not in any prior loop | |
| 159 } else { | |
| 160 old_ctrl = get_ctrl(x); | |
| 161 old_loop = get_loop(old_ctrl); // Get prior loop | |
| 162 } | |
| 163 // New late point must dominate new use | |
| 164 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2)); | |
| 165 if (new_ctrl == old_ctrl) // Nothing is changed | |
| 166 continue; | |
| 167 | |
| 168 IdealLoopTree *new_loop = get_loop(new_ctrl); | |
| 169 | |
| 170 // Don't move x into a loop if its uses are | |
| 171 // outside of loop. Otherwise x will be cloned | |
| 172 // for each use outside of this loop. | |
| 173 IdealLoopTree *use_loop = get_loop(region); | |
| 174 if (!new_loop->is_member(use_loop) && | |
| 175 (old_loop == NULL || !new_loop->is_member(old_loop))) { | |
| 176 // Take early control, later control will be recalculated | |
| 177 // during next iteration of loop optimizations. | |
| 178 new_ctrl = get_early_ctrl(x); | |
| 179 new_loop = get_loop(new_ctrl); | |
| 180 } | |
| 181 // Set new location | |
| 182 set_ctrl(x, new_ctrl); | |
| 183 // If changing loop bodies, see if we need to collect into new body | |
| 184 if (old_loop != new_loop) { | |
| 185 if (old_loop && !old_loop->_child) | |
| 186 old_loop->_body.yank(x); | |
| 187 if (!new_loop->_child) | |
| 188 new_loop->_body.push(x); // Collect body info | |
| 189 } | |
| 190 } | |
| 191 | |
| 192 return phi; | |
| 193 } | |
| 194 | |
| 195 //------------------------------dominated_by------------------------------------ | |
| 196 // Replace the dominated test with an obvious true or false. Place it on the | |
| 197 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the | |
| 198 // live path up to the dominating control. | |
| 199 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) { | |
| 200 #ifndef PRODUCT | |
| 201 if (VerifyLoopOptimizations && PrintOpto) tty->print_cr("dominating test"); | |
| 202 #endif | |
| 203 | |
| 204 | |
| 205 // prevdom is the dominating projection of the dominating test. | |
| 206 assert( iff->is_If(), "" ); | |
| 207 assert( iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
| 208 int pop = prevdom->Opcode(); | |
| 209 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); | |
| 210 if (flip) { | |
| 211 if (pop == Op_IfTrue) | |
| 212 pop = Op_IfFalse; | |
| 213 else | |
| 214 pop = Op_IfTrue; | |
| 215 } | |
| 216 // 'con' is set to true or false to kill the dominated test. | |
| 217 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); | |
| 218 set_ctrl(con, C->root()); // Constant gets a new use | |
| 219 // Hack the dominated test | |
| 220 _igvn.replace_input_of(iff, 1, con); | |
| 221 | |
| 222 // If I dont have a reachable TRUE and FALSE path following the IfNode then | |
| 223 // I can assume this path reaches an infinite loop. In this case it's not | |
| 224 // important to optimize the data Nodes - either the whole compilation will | |
| 225 // be tossed or this path (and all data Nodes) will go dead. | |
| 226 if (iff->outcnt() != 2) return; | |
| 227 | |
| 228 // Make control-dependent data Nodes on the live path (path that will remain | |
| 229 // once the dominated IF is removed) become control-dependent on the | |
| 230 // dominating projection. | |
| 231 Node* dp = iff->as_If()->proj_out(pop == Op_IfTrue); | |
| 232 | |
| 233 // Loop predicates may have depending checks which should not | |
| 234 // be skipped. For example, range check predicate has two checks | |
| 235 // for lower and upper bounds. | |
| 236 if (dp == NULL) | |
| 237 return; | |
| 238 | |
| 239 ProjNode* dp_proj = dp->as_Proj(); | |
| 240 ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj(); | |
| 241 if (exclude_loop_predicate && | |
| 242 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate)) | |
| 243 return; // Let IGVN transformation change control dependence. | |
| 244 | |
| 245 IdealLoopTree *old_loop = get_loop(dp); | |
| 246 | |
| 247 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
| 248 Node* cd = dp->fast_out(i); // Control-dependent node | |
| 249 if (cd->depends_only_on_test()) { | |
| 250 assert(cd->in(0) == dp, ""); | |
| 251 _igvn.replace_input_of(cd, 0, prevdom); | |
| 252 set_early_ctrl(cd); | |
| 253 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); | |
| 254 if (old_loop != new_loop) { | |
| 255 if (!old_loop->_child) old_loop->_body.yank(cd); | |
| 256 if (!new_loop->_child) new_loop->_body.push(cd); | |
| 257 } | |
| 258 --i; | |
| 259 --imax; | |
| 260 } | |
| 261 } | |
| 262 } | |
| 263 | |
| 264 //------------------------------has_local_phi_input---------------------------- | |
| 265 // Return TRUE if 'n' has Phi inputs from its local block and no other | |
| 266 // block-local inputs (all non-local-phi inputs come from earlier blocks) | |
| 267 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { | |
| 268 Node *n_ctrl = get_ctrl(n); | |
| 269 // See if some inputs come from a Phi in this block, or from before | |
| 270 // this block. | |
| 271 uint i; | |
| 272 for( i = 1; i < n->req(); i++ ) { | |
| 273 Node *phi = n->in(i); | |
| 274 if( phi->is_Phi() && phi->in(0) == n_ctrl ) | |
| 275 break; | |
| 276 } | |
| 277 if( i >= n->req() ) | |
| 278 return NULL; // No Phi inputs; nowhere to clone thru | |
| 279 | |
| 280 // Check for inputs created between 'n' and the Phi input. These | |
| 281 // must split as well; they have already been given the chance | |
| 282 // (courtesy of a post-order visit) and since they did not we must | |
| 283 // recover the 'cost' of splitting them by being very profitable | |
| 284 // when splitting 'n'. Since this is unlikely we simply give up. | |
| 285 for( i = 1; i < n->req(); i++ ) { | |
| 286 Node *m = n->in(i); | |
| 287 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { | |
| 288 // We allow the special case of AddP's with no local inputs. | |
| 289 // This allows us to split-up address expressions. | |
| 290 if (m->is_AddP() && | |
| 291 get_ctrl(m->in(2)) != n_ctrl && | |
| 292 get_ctrl(m->in(3)) != n_ctrl) { | |
| 293 // Move the AddP up to dominating point | |
| 294 set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); | |
| 295 continue; | |
| 296 } | |
| 297 return NULL; | |
| 298 } | |
| 299 } | |
| 300 | |
| 301 return n_ctrl; | |
| 302 } | |
| 303 | |
| 304 //------------------------------remix_address_expressions---------------------- | |
| 305 // Rework addressing expressions to get the most loop-invariant stuff | |
| 306 // moved out. We'd like to do all associative operators, but it's especially | |
| 307 // important (common) to do address expressions. | |
| 308 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { | |
| 309 if (!has_ctrl(n)) return NULL; | |
| 310 Node *n_ctrl = get_ctrl(n); | |
| 311 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
| 312 | |
| 313 // See if 'n' mixes loop-varying and loop-invariant inputs and | |
| 314 // itself is loop-varying. | |
| 315 | |
| 316 // Only interested in binary ops (and AddP) | |
| 317 if( n->req() < 3 || n->req() > 4 ) return NULL; | |
| 318 | |
| 319 Node *n1_ctrl = get_ctrl(n->in( 1)); | |
| 320 Node *n2_ctrl = get_ctrl(n->in( 2)); | |
| 321 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); | |
| 322 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); | |
| 323 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); | |
| 324 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); | |
| 325 | |
| 326 // Does one of my inputs spin in a tighter loop than self? | |
| 327 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || | |
| 328 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || | |
| 329 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) | |
| 330 return NULL; // Leave well enough alone | |
| 331 | |
| 332 // Is at least one of my inputs loop-invariant? | |
| 333 if( n1_loop == n_loop && | |
| 334 n2_loop == n_loop && | |
| 335 n3_loop == n_loop ) | |
| 336 return NULL; // No loop-invariant inputs | |
| 337 | |
| 338 | |
| 339 int n_op = n->Opcode(); | |
| 340 | |
| 341 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). | |
| 342 if( n_op == Op_LShiftI ) { | |
| 343 // Scale is loop invariant | |
| 344 Node *scale = n->in(2); | |
| 345 Node *scale_ctrl = get_ctrl(scale); | |
| 346 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); | |
| 347 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) | |
| 348 return NULL; | |
| 349 const TypeInt *scale_t = scale->bottom_type()->isa_int(); | |
| 350 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) | |
| 351 return NULL; // Dont bother with byte/short masking | |
| 352 // Add must vary with loop (else shift would be loop-invariant) | |
| 353 Node *add = n->in(1); | |
| 354 Node *add_ctrl = get_ctrl(add); | |
| 355 IdealLoopTree *add_loop = get_loop(add_ctrl); | |
| 356 //assert( n_loop == add_loop, "" ); | |
| 357 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops | |
| 358 | |
| 359 // Convert I-V into I+ (0-V); same for V-I | |
| 360 if( add->Opcode() == Op_SubI && | |
| 361 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { | |
| 362 Node *zero = _igvn.intcon(0); | |
| 363 set_ctrl(zero, C->root()); | |
| 364 Node *neg = new (C) SubINode( _igvn.intcon(0), add->in(2) ); | |
| 365 register_new_node( neg, get_ctrl(add->in(2) ) ); | |
| 366 add = new (C) AddINode( add->in(1), neg ); | |
| 367 register_new_node( add, add_ctrl ); | |
| 368 } | |
| 369 if( add->Opcode() != Op_AddI ) return NULL; | |
| 370 // See if one add input is loop invariant | |
| 371 Node *add_var = add->in(1); | |
| 372 Node *add_var_ctrl = get_ctrl(add_var); | |
| 373 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
| 374 Node *add_invar = add->in(2); | |
| 375 Node *add_invar_ctrl = get_ctrl(add_invar); | |
| 376 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); | |
| 377 if( add_var_loop == n_loop ) { | |
| 378 } else if( add_invar_loop == n_loop ) { | |
| 379 // Swap to find the invariant part | |
| 380 add_invar = add_var; | |
| 381 add_invar_ctrl = add_var_ctrl; | |
| 382 add_invar_loop = add_var_loop; | |
| 383 add_var = add->in(2); | |
| 384 Node *add_var_ctrl = get_ctrl(add_var); | |
| 385 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
| 386 } else // Else neither input is loop invariant | |
| 387 return NULL; | |
| 388 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) | |
| 389 return NULL; // No invariant part of the add? | |
| 390 | |
| 391 // Yes! Reshape address expression! | |
| 392 Node *inv_scale = new (C) LShiftINode( add_invar, scale ); | |
| 393 Node *inv_scale_ctrl = | |
| 394 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? | |
| 395 add_invar_ctrl : scale_ctrl; | |
| 396 register_new_node( inv_scale, inv_scale_ctrl ); | |
| 397 Node *var_scale = new (C) LShiftINode( add_var, scale ); | |
| 398 register_new_node( var_scale, n_ctrl ); | |
| 399 Node *var_add = new (C) AddINode( var_scale, inv_scale ); | |
| 400 register_new_node( var_add, n_ctrl ); | |
| 401 _igvn.replace_node( n, var_add ); | |
| 402 return var_add; | |
| 403 } | |
| 404 | |
| 405 // Replace (I+V) with (V+I) | |
| 406 if( n_op == Op_AddI || | |
| 407 n_op == Op_AddL || | |
| 408 n_op == Op_AddF || | |
| 409 n_op == Op_AddD || | |
| 410 n_op == Op_MulI || | |
| 411 n_op == Op_MulL || | |
| 412 n_op == Op_MulF || | |
| 413 n_op == Op_MulD ) { | |
| 414 if( n2_loop == n_loop ) { | |
| 415 assert( n1_loop != n_loop, "" ); | |
| 416 n->swap_edges(1, 2); | |
| 417 } | |
| 418 } | |
| 419 | |
| 420 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), | |
| 421 // but not if I2 is a constant. | |
| 422 if( n_op == Op_AddP ) { | |
| 423 if( n2_loop == n_loop && n3_loop != n_loop ) { | |
| 424 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { | |
| 425 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); | |
| 426 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); | |
| 427 IdealLoopTree *n22loop = get_loop( n22_ctrl ); | |
| 428 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); | |
| 429 if( n22loop != n_loop && n22loop->is_member(n_loop) && | |
| 430 n23_loop == n_loop ) { | |
| 431 Node *add1 = new (C) AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); | |
| 432 // Stuff new AddP in the loop preheader | |
| 433 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
| 434 Node *add2 = new (C) AddPNode( n->in(1), add1, n->in(2)->in(3) ); | |
| 435 register_new_node( add2, n_ctrl ); | |
| 436 _igvn.replace_node( n, add2 ); | |
| 437 return add2; | |
| 438 } | |
| 439 } | |
| 440 } | |
| 441 | |
| 442 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) | |
| 443 if( n2_loop != n_loop && n3_loop == n_loop ) { | |
| 444 if( n->in(3)->Opcode() == Op_AddI ) { | |
| 445 Node *V = n->in(3)->in(1); | |
| 446 Node *I = n->in(3)->in(2); | |
| 447 if( is_member(n_loop,get_ctrl(V)) ) { | |
| 448 } else { | |
| 449 Node *tmp = V; V = I; I = tmp; | |
| 450 } | |
| 451 if( !is_member(n_loop,get_ctrl(I)) ) { | |
| 452 Node *add1 = new (C) AddPNode( n->in(1), n->in(2), I ); | |
| 453 // Stuff new AddP in the loop preheader | |
| 454 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
| 455 Node *add2 = new (C) AddPNode( n->in(1), add1, V ); | |
| 456 register_new_node( add2, n_ctrl ); | |
| 457 _igvn.replace_node( n, add2 ); | |
| 458 return add2; | |
| 459 } | |
| 460 } | |
| 461 } | |
| 462 } | |
| 463 | |
| 464 return NULL; | |
| 465 } | |
| 466 | |
| 467 //------------------------------conditional_move------------------------------- | |
| 468 // Attempt to replace a Phi with a conditional move. We have some pretty | |
| 469 // strict profitability requirements. All Phis at the merge point must | |
| 470 // be converted, so we can remove the control flow. We need to limit the | |
| 471 // number of c-moves to a small handful. All code that was in the side-arms | |
| 472 // of the CFG diamond is now speculatively executed. This code has to be | |
| 473 // "cheap enough". We are pretty much limited to CFG diamonds that merge | |
| 474 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. | |
| 475 Node *PhaseIdealLoop::conditional_move( Node *region ) { | |
| 476 | |
| 477 assert(region->is_Region(), "sanity check"); | |
| 478 if (region->req() != 3) return NULL; | |
| 479 | |
| 480 // Check for CFG diamond | |
| 481 Node *lp = region->in(1); | |
| 482 Node *rp = region->in(2); | |
| 483 if (!lp || !rp) return NULL; | |
| 484 Node *lp_c = lp->in(0); | |
| 485 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL; | |
| 486 IfNode *iff = lp_c->as_If(); | |
| 487 | |
| 488 // Check for ops pinned in an arm of the diamond. | |
| 489 // Can't remove the control flow in this case | |
| 490 if (lp->outcnt() > 1) return NULL; | |
| 491 if (rp->outcnt() > 1) return NULL; | |
| 492 | |
| 493 IdealLoopTree* r_loop = get_loop(region); | |
| 494 assert(r_loop == get_loop(iff), "sanity"); | |
| 495 // Always convert to CMOVE if all results are used only outside this loop. | |
| 496 bool used_inside_loop = (r_loop == _ltree_root); | |
| 497 | |
| 498 // Check profitability | |
| 499 int cost = 0; | |
| 500 int phis = 0; | |
| 501 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
| 502 Node *out = region->fast_out(i); | |
| 503 if (!out->is_Phi()) continue; // Ignore other control edges, etc | |
| 504 phis++; | |
| 505 PhiNode* phi = out->as_Phi(); | |
| 506 BasicType bt = phi->type()->basic_type(); | |
| 507 switch (bt) { | |
| 508 case T_FLOAT: | |
| 509 case T_DOUBLE: { | |
| 510 cost += Matcher::float_cmove_cost(); // Could be very expensive | |
| 511 break; | |
| 512 } | |
| 513 case T_LONG: { | |
| 514 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's | |
| 515 } | |
| 516 case T_INT: // These all CMOV fine | |
| 517 case T_ADDRESS: { // (RawPtr) | |
| 518 cost++; | |
| 519 break; | |
| 520 } | |
| 521 case T_NARROWOOP: // Fall through | |
| 522 case T_OBJECT: { // Base oops are OK, but not derived oops | |
| 523 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); | |
| 524 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a | |
| 525 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus | |
| 526 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we | |
| 527 // have a Phi for the base here that we convert to a CMOVE all is well | |
| 528 // and good. But if the base is dead, we'll not make a CMOVE. Later | |
| 529 // the allocator will have to produce a base by creating a CMOVE of the | |
| 530 // relevant bases. This puts the allocator in the business of | |
| 531 // manufacturing expensive instructions, generally a bad plan. | |
| 532 // Just Say No to Conditionally-Moved Derived Pointers. | |
| 533 if (tp && tp->offset() != 0) | |
| 534 return NULL; | |
| 535 cost++; | |
| 536 break; | |
| 537 } | |
| 538 default: | |
| 539 return NULL; // In particular, can't do memory or I/O | |
| 540 } | |
| 541 // Add in cost any speculative ops | |
| 542 for (uint j = 1; j < region->req(); j++) { | |
| 543 Node *proj = region->in(j); | |
| 544 Node *inp = phi->in(j); | |
| 545 if (get_ctrl(inp) == proj) { // Found local op | |
| 546 cost++; | |
| 547 // Check for a chain of dependent ops; these will all become | |
| 548 // speculative in a CMOV. | |
| 549 for (uint k = 1; k < inp->req(); k++) | |
| 550 if (get_ctrl(inp->in(k)) == proj) | |
| 551 cost += ConditionalMoveLimit; // Too much speculative goo | |
| 552 } | |
| 553 } | |
| 554 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. | |
| 555 // This will likely Split-If, a higher-payoff operation. | |
| 556 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { | |
| 557 Node* use = phi->fast_out(k); | |
| 558 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr()) | |
| 559 cost += ConditionalMoveLimit; | |
| 560 // Is there a use inside the loop? | |
| 561 // Note: check only basic types since CMoveP is pinned. | |
| 562 if (!used_inside_loop && is_java_primitive(bt)) { | |
| 563 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use); | |
| 564 if (r_loop == u_loop || r_loop->is_member(u_loop)) { | |
| 565 used_inside_loop = true; | |
| 566 } | |
| 567 } | |
| 568 } | |
| 569 } | |
| 570 Node* bol = iff->in(1); | |
| 571 assert(bol->Opcode() == Op_Bool, ""); | |
| 572 int cmp_op = bol->in(1)->Opcode(); | |
| 573 // It is expensive to generate flags from a float compare. | |
| 574 // Avoid duplicated float compare. | |
| 575 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; | |
| 576 | |
| 577 float infrequent_prob = PROB_UNLIKELY_MAG(3); | |
| 578 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop. | |
| 579 if (used_inside_loop) { | |
| 580 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo | |
| 581 | |
| 582 // BlockLayoutByFrequency optimization moves infrequent branch | |
| 583 // from hot path. No point in CMOV'ing in such case (110 is used | |
| 584 // instead of 100 to take into account not exactness of float value). | |
| 585 if (BlockLayoutByFrequency) { | |
| 586 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f); | |
| 587 } | |
| 588 } | |
| 589 // Check for highly predictable branch. No point in CMOV'ing if | |
| 590 // we are going to predict accurately all the time. | |
| 591 if (iff->_prob < infrequent_prob || | |
| 592 iff->_prob > (1.0f - infrequent_prob)) | |
| 593 return NULL; | |
| 594 | |
| 595 // -------------- | |
| 596 // Now replace all Phis with CMOV's | |
| 597 Node *cmov_ctrl = iff->in(0); | |
| 598 uint flip = (lp->Opcode() == Op_IfTrue); | |
| 599 while (1) { | |
| 600 PhiNode* phi = NULL; | |
| 601 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
| 602 Node *out = region->fast_out(i); | |
| 603 if (out->is_Phi()) { | |
| 604 phi = out->as_Phi(); | |
| 605 break; | |
| 606 } | |
| 607 } | |
| 608 if (phi == NULL) break; | |
| 609 #ifndef PRODUCT | |
| 610 if (PrintOpto && VerifyLoopOptimizations) tty->print_cr("CMOV"); | |
| 611 #endif | |
| 612 // Move speculative ops | |
| 613 for (uint j = 1; j < region->req(); j++) { | |
| 614 Node *proj = region->in(j); | |
| 615 Node *inp = phi->in(j); | |
| 616 if (get_ctrl(inp) == proj) { // Found local op | |
| 617 #ifndef PRODUCT | |
| 618 if (PrintOpto && VerifyLoopOptimizations) { | |
| 619 tty->print(" speculate: "); | |
| 620 inp->dump(); | |
| 621 } | |
| 622 #endif | |
| 623 set_ctrl(inp, cmov_ctrl); | |
| 624 } | |
| 625 } | |
| 626 Node *cmov = CMoveNode::make( C, cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi) ); | |
| 627 register_new_node( cmov, cmov_ctrl ); | |
| 628 _igvn.replace_node( phi, cmov ); | |
| 629 #ifndef PRODUCT | |
| 630 if (TraceLoopOpts) { | |
| 631 tty->print("CMOV "); | |
| 632 r_loop->dump_head(); | |
| 633 if (Verbose) { | |
| 634 bol->in(1)->dump(1); | |
| 635 cmov->dump(1); | |
| 636 } | |
| 637 } | |
| 638 if (VerifyLoopOptimizations) verify(); | |
| 639 #endif | |
| 640 } | |
| 641 | |
| 642 // The useless CFG diamond will fold up later; see the optimization in | |
| 643 // RegionNode::Ideal. | |
| 644 _igvn._worklist.push(region); | |
| 645 | |
| 646 return iff->in(1); | |
| 647 } | |
| 648 | |
| 649 //------------------------------split_if_with_blocks_pre----------------------- | |
| 650 // Do the real work in a non-recursive function. Data nodes want to be | |
| 651 // cloned in the pre-order so they can feed each other nicely. | |
| 652 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { | |
| 653 // Cloning these guys is unlikely to win | |
| 654 int n_op = n->Opcode(); | |
| 655 if( n_op == Op_MergeMem ) return n; | |
| 656 if( n->is_Proj() ) return n; | |
| 657 // Do not clone-up CmpFXXX variations, as these are always | |
| 658 // followed by a CmpI | |
| 659 if( n->is_Cmp() ) return n; | |
| 660 // Attempt to use a conditional move instead of a phi/branch | |
| 661 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { | |
| 662 Node *cmov = conditional_move( n ); | |
| 663 if( cmov ) return cmov; | |
| 664 } | |
| 665 if( n->is_CFG() || n->is_LoadStore() ) | |
| 666 return n; | |
| 667 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd | |
| 668 n_op == Op_Opaque2 ) { | |
| 669 if( !C->major_progress() ) // If chance of no more loop opts... | |
| 670 _igvn._worklist.push(n); // maybe we'll remove them | |
| 671 return n; | |
| 672 } | |
| 673 | |
| 674 if( n->is_Con() ) return n; // No cloning for Con nodes | |
| 675 | |
| 676 Node *n_ctrl = get_ctrl(n); | |
| 677 if( !n_ctrl ) return n; // Dead node | |
| 678 | |
| 679 // Attempt to remix address expressions for loop invariants | |
| 680 Node *m = remix_address_expressions( n ); | |
| 681 if( m ) return m; | |
| 682 | |
| 683 // Determine if the Node has inputs from some local Phi. | |
| 684 // Returns the block to clone thru. | |
| 685 Node *n_blk = has_local_phi_input( n ); | |
| 686 if( !n_blk ) return n; | |
| 687 // Do not clone the trip counter through on a CountedLoop | |
| 688 // (messes up the canonical shape). | |
| 689 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; | |
| 690 | |
| 691 // Check for having no control input; not pinned. Allow | |
| 692 // dominating control. | |
| 693 if( n->in(0) ) { | |
| 694 Node *dom = idom(n_blk); | |
| 695 if( dom_lca( n->in(0), dom ) != n->in(0) ) | |
| 696 return n; | |
| 697 } | |
| 698 // Policy: when is it profitable. You must get more wins than | |
| 699 // policy before it is considered profitable. Policy is usually 0, | |
| 700 // so 1 win is considered profitable. Big merges will require big | |
| 701 // cloning, so get a larger policy. | |
| 702 int policy = n_blk->req() >> 2; | |
| 703 | |
| 704 // If the loop is a candidate for range check elimination, | |
| 705 // delay splitting through it's phi until a later loop optimization | |
| 706 if (n_blk->is_CountedLoop()) { | |
| 707 IdealLoopTree *lp = get_loop(n_blk); | |
| 708 if (lp && lp->_rce_candidate) { | |
| 709 return n; | |
| 710 } | |
| 711 } | |
| 712 | |
| 713 // Use same limit as split_if_with_blocks_post | |
| 714 if( C->unique() > 35000 ) return n; // Method too big | |
| 715 | |
| 716 // Split 'n' through the merge point if it is profitable | |
| 717 Node *phi = split_thru_phi( n, n_blk, policy ); | |
| 718 if (!phi) return n; | |
| 719 | |
| 720 // Found a Phi to split thru! | |
| 721 // Replace 'n' with the new phi | |
| 722 _igvn.replace_node( n, phi ); | |
| 723 // Moved a load around the loop, 'en-registering' something. | |
| 724 if (n_blk->is_Loop() && n->is_Load() && | |
| 725 !phi->in(LoopNode::LoopBackControl)->is_Load()) | |
| 726 C->set_major_progress(); | |
| 727 | |
| 728 return phi; | |
| 729 } | |
| 730 | |
| 731 static bool merge_point_too_heavy(Compile* C, Node* region) { | |
| 732 // Bail out if the region and its phis have too many users. | |
| 733 int weight = 0; | |
| 734 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
| 735 weight += region->fast_out(i)->outcnt(); | |
| 736 } | |
| 737 int nodes_left = MaxNodeLimit - C->live_nodes(); | |
| 738 if (weight * 8 > nodes_left) { | |
| 739 #ifndef PRODUCT | |
| 740 if (PrintOpto) | |
| 741 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); | |
| 742 #endif | |
| 743 return true; | |
| 744 } else { | |
| 745 return false; | |
| 746 } | |
| 747 } | |
| 748 | |
| 749 static bool merge_point_safe(Node* region) { | |
| 750 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode | |
| 751 // having a PhiNode input. This sidesteps the dangerous case where the split | |
| 752 // ConvI2LNode may become TOP if the input Value() does not | |
| 753 // overlap the ConvI2L range, leaving a node which may not dominate its | |
| 754 // uses. | |
| 755 // A better fix for this problem can be found in the BugTraq entry, but | |
| 756 // expediency for Mantis demands this hack. | |
| 757 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop | |
| 758 // split_if_with_blocks from splitting a block because we could not move around | |
| 759 // the FastLockNode. | |
| 760 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
| 761 Node* n = region->fast_out(i); | |
| 762 if (n->is_Phi()) { | |
| 763 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 764 Node* m = n->fast_out(j); | |
| 765 if (m->is_FastLock()) | |
| 766 return false; | |
| 767 #ifdef _LP64 | |
| 768 if (m->Opcode() == Op_ConvI2L) | |
| 769 return false; | |
| 770 #endif | |
| 771 } | |
| 772 } | |
| 773 } | |
| 774 return true; | |
| 775 } | |
| 776 | |
| 777 | |
| 778 //------------------------------place_near_use--------------------------------- | |
| 779 // Place some computation next to use but not inside inner loops. | |
| 780 // For inner loop uses move it to the preheader area. | |
| 781 Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { | |
| 782 IdealLoopTree *u_loop = get_loop( useblock ); | |
| 783 return (u_loop->_irreducible || u_loop->_child) | |
| 784 ? useblock | |
| 785 : u_loop->_head->in(LoopNode::EntryControl); | |
| 786 } | |
| 787 | |
| 788 | |
| 789 //------------------------------split_if_with_blocks_post---------------------- | |
| 790 // Do the real work in a non-recursive function. CFG hackery wants to be | |
| 791 // in the post-order, so it can dirty the I-DOM info and not use the dirtied | |
| 792 // info. | |
| 793 void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) { | |
| 794 | |
| 795 // Cloning Cmp through Phi's involves the split-if transform. | |
| 796 // FastLock is not used by an If | |
| 797 if( n->is_Cmp() && !n->is_FastLock() ) { | |
| 798 if( C->unique() > 35000 ) return; // Method too big | |
| 799 | |
| 800 // Do not do 'split-if' if irreducible loops are present. | |
| 801 if( _has_irreducible_loops ) | |
| 802 return; | |
| 803 | |
| 804 Node *n_ctrl = get_ctrl(n); | |
| 805 // Determine if the Node has inputs from some local Phi. | |
| 806 // Returns the block to clone thru. | |
| 807 Node *n_blk = has_local_phi_input( n ); | |
| 808 if( n_blk != n_ctrl ) return; | |
| 809 | |
| 810 if( merge_point_too_heavy(C, n_ctrl) ) | |
| 811 return; | |
| 812 | |
| 813 if( n->outcnt() != 1 ) return; // Multiple bool's from 1 compare? | |
| 814 Node *bol = n->unique_out(); | |
| 815 assert( bol->is_Bool(), "expect a bool here" ); | |
| 816 if( bol->outcnt() != 1 ) return;// Multiple branches from 1 compare? | |
| 817 Node *iff = bol->unique_out(); | |
| 818 | |
| 819 // Check some safety conditions | |
| 820 if( iff->is_If() ) { // Classic split-if? | |
| 821 if( iff->in(0) != n_ctrl ) return; // Compare must be in same blk as if | |
| 822 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE | |
| 823 // Can't split CMove with different control edge. | |
| 824 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) return; | |
| 825 if( get_ctrl(iff->in(2)) == n_ctrl || | |
| 826 get_ctrl(iff->in(3)) == n_ctrl ) | |
| 827 return; // Inputs not yet split-up | |
| 828 if ( get_loop(n_ctrl) != get_loop(get_ctrl(iff)) ) { | |
| 829 return; // Loop-invar test gates loop-varying CMOVE | |
| 830 } | |
| 831 } else { | |
| 832 return; // some other kind of node, such as an Allocate | |
| 833 } | |
| 834 | |
| 835 // Do not do 'split-if' if some paths are dead. First do dead code | |
| 836 // elimination and then see if its still profitable. | |
| 837 for( uint i = 1; i < n_ctrl->req(); i++ ) | |
| 838 if( n_ctrl->in(i) == C->top() ) | |
| 839 return; | |
| 840 | |
| 841 // When is split-if profitable? Every 'win' on means some control flow | |
| 842 // goes dead, so it's almost always a win. | |
| 843 int policy = 0; | |
| 844 // If trying to do a 'Split-If' at the loop head, it is only | |
| 845 // profitable if the cmp folds up on BOTH paths. Otherwise we | |
| 846 // risk peeling a loop forever. | |
| 847 | |
| 848 // CNC - Disabled for now. Requires careful handling of loop | |
| 849 // body selection for the cloned code. Also, make sure we check | |
| 850 // for any input path not being in the same loop as n_ctrl. For | |
| 851 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' | |
| 852 // because the alternative loop entry points won't be converted | |
| 853 // into LoopNodes. | |
| 854 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
| 855 for( uint j = 1; j < n_ctrl->req(); j++ ) | |
| 856 if( get_loop(n_ctrl->in(j)) != n_loop ) | |
| 857 return; | |
| 858 | |
| 859 // Check for safety of the merge point. | |
| 860 if( !merge_point_safe(n_ctrl) ) { | |
| 861 return; | |
| 862 } | |
| 863 | |
| 864 // Split compare 'n' through the merge point if it is profitable | |
| 865 Node *phi = split_thru_phi( n, n_ctrl, policy ); | |
| 866 if( !phi ) return; | |
| 867 | |
| 868 // Found a Phi to split thru! | |
| 869 // Replace 'n' with the new phi | |
| 870 _igvn.replace_node( n, phi ); | |
| 871 | |
| 872 // Now split the bool up thru the phi | |
| 873 Node *bolphi = split_thru_phi( bol, n_ctrl, -1 ); | |
| 874 guarantee(bolphi != NULL, "null boolean phi node"); | |
| 875 | |
| 876 _igvn.replace_node( bol, bolphi ); | |
| 877 assert( iff->in(1) == bolphi, "" ); | |
| 878 | |
| 879 if( bolphi->Value(&_igvn)->singleton() ) | |
| 880 return; | |
| 881 | |
| 882 // Conditional-move? Must split up now | |
| 883 if( !iff->is_If() ) { | |
| 884 Node *cmovphi = split_thru_phi( iff, n_ctrl, -1 ); | |
| 885 _igvn.replace_node( iff, cmovphi ); | |
| 886 return; | |
| 887 } | |
| 888 | |
| 889 // Now split the IF | |
| 890 do_split_if( iff ); | |
| 891 return; | |
| 892 } | |
| 893 | |
| 894 // Check for an IF ready to split; one that has its | |
| 895 // condition codes input coming from a Phi at the block start. | |
| 896 int n_op = n->Opcode(); | |
| 897 | |
| 898 // Check for an IF being dominated by another IF same test | |
| 899 if( n_op == Op_If ) { | |
| 900 Node *bol = n->in(1); | |
| 901 uint max = bol->outcnt(); | |
| 902 // Check for same test used more than once? | |
| 903 if( n_op == Op_If && max > 1 && bol->is_Bool() ) { | |
| 904 // Search up IDOMs to see if this IF is dominated. | |
| 905 Node *cutoff = get_ctrl(bol); | |
| 906 | |
| 907 // Now search up IDOMs till cutoff, looking for a dominating test | |
| 908 Node *prevdom = n; | |
| 909 Node *dom = idom(prevdom); | |
| 910 while( dom != cutoff ) { | |
| 911 if( dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom ) { | |
| 912 // Replace the dominated test with an obvious true or false. | |
| 913 // Place it on the IGVN worklist for later cleanup. | |
| 914 C->set_major_progress(); | |
| 915 dominated_by( prevdom, n, false, true ); | |
| 916 #ifndef PRODUCT | |
| 917 if( VerifyLoopOptimizations ) verify(); | |
| 918 #endif | |
| 919 return; | |
| 920 } | |
| 921 prevdom = dom; | |
| 922 dom = idom(prevdom); | |
| 923 } | |
| 924 } | |
| 925 } | |
| 926 | |
| 927 // See if a shared loop-varying computation has no loop-varying uses. | |
| 928 // Happens if something is only used for JVM state in uncommon trap exits, | |
| 929 // like various versions of induction variable+offset. Clone the | |
| 930 // computation per usage to allow it to sink out of the loop. | |
| 931 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) | |
| 932 Node *n_ctrl = get_ctrl(n); | |
| 933 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
| 934 if( n_loop != _ltree_root ) { | |
| 935 DUIterator_Fast imax, i = n->fast_outs(imax); | |
| 936 for (; i < imax; i++) { | |
| 937 Node* u = n->fast_out(i); | |
| 938 if( !has_ctrl(u) ) break; // Found control user | |
| 939 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); | |
| 940 if( u_loop == n_loop ) break; // Found loop-varying use | |
| 941 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop | |
| 942 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 | |
| 943 } | |
| 944 bool did_break = (i < imax); // Did we break out of the previous loop? | |
| 945 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! | |
| 946 Node *late_load_ctrl = NULL; | |
| 947 if (n->is_Load()) { | |
| 948 // If n is a load, get and save the result from get_late_ctrl(), | |
| 949 // to be later used in calculating the control for n's clones. | |
| 950 clear_dom_lca_tags(); | |
| 951 late_load_ctrl = get_late_ctrl(n, n_ctrl); | |
| 952 } | |
| 953 // If n is a load, and the late control is the same as the current | |
| 954 // control, then the cloning of n is a pointless exercise, because | |
| 955 // GVN will ensure that we end up where we started. | |
| 956 if (!n->is_Load() || late_load_ctrl != n_ctrl) { | |
| 957 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { | |
| 958 Node *u = n->last_out(j); // Clone private computation per use | |
| 959 _igvn.rehash_node_delayed(u); | |
| 960 Node *x = n->clone(); // Clone computation | |
| 961 Node *x_ctrl = NULL; | |
| 962 if( u->is_Phi() ) { | |
| 963 // Replace all uses of normal nodes. Replace Phi uses | |
| 964 // individually, so the separate Nodes can sink down | |
| 965 // different paths. | |
| 966 uint k = 1; | |
| 967 while( u->in(k) != n ) k++; | |
| 968 u->set_req( k, x ); | |
| 969 // x goes next to Phi input path | |
| 970 x_ctrl = u->in(0)->in(k); | |
| 971 --j; | |
| 972 } else { // Normal use | |
| 973 // Replace all uses | |
| 974 for( uint k = 0; k < u->req(); k++ ) { | |
| 975 if( u->in(k) == n ) { | |
| 976 u->set_req( k, x ); | |
| 977 --j; | |
| 978 } | |
| 979 } | |
| 980 x_ctrl = get_ctrl(u); | |
| 981 } | |
| 982 | |
| 983 // Find control for 'x' next to use but not inside inner loops. | |
| 984 // For inner loop uses get the preheader area. | |
| 985 x_ctrl = place_near_use(x_ctrl); | |
| 986 | |
| 987 if (n->is_Load()) { | |
| 988 // For loads, add a control edge to a CFG node outside of the loop | |
| 989 // to force them to not combine and return back inside the loop | |
| 990 // during GVN optimization (4641526). | |
| 991 // | |
| 992 // Because we are setting the actual control input, factor in | |
| 993 // the result from get_late_ctrl() so we respect any | |
| 994 // anti-dependences. (6233005). | |
| 995 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); | |
| 996 | |
| 997 // Don't allow the control input to be a CFG splitting node. | |
| 998 // Such nodes should only have ProjNodes as outs, e.g. IfNode | |
| 999 // should only have IfTrueNode and IfFalseNode (4985384). | |
| 1000 x_ctrl = find_non_split_ctrl(x_ctrl); | |
| 1001 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); | |
| 1002 | |
| 1003 x->set_req(0, x_ctrl); | |
| 1004 } | |
| 1005 register_new_node(x, x_ctrl); | |
| 1006 | |
| 1007 // Some institutional knowledge is needed here: 'x' is | |
| 1008 // yanked because if the optimizer runs GVN on it all the | |
| 1009 // cloned x's will common up and undo this optimization and | |
| 1010 // be forced back in the loop. This is annoying because it | |
| 1011 // makes +VerifyOpto report false-positives on progress. I | |
| 1012 // tried setting control edges on the x's to force them to | |
| 1013 // not combine, but the matching gets worried when it tries | |
| 1014 // to fold a StoreP and an AddP together (as part of an | |
| 1015 // address expression) and the AddP and StoreP have | |
| 1016 // different controls. | |
| 1017 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x); | |
| 1018 } | |
| 1019 _igvn.remove_dead_node(n); | |
| 1020 } | |
| 1021 } | |
| 1022 } | |
| 1023 } | |
| 1024 | |
| 1025 // Check for Opaque2's who's loop has disappeared - who's input is in the | |
| 1026 // same loop nest as their output. Remove 'em, they are no longer useful. | |
| 1027 if( n_op == Op_Opaque2 && | |
| 1028 n->in(1) != NULL && | |
| 1029 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { | |
| 1030 _igvn.replace_node( n, n->in(1) ); | |
| 1031 } | |
| 1032 } | |
| 1033 | |
| 1034 //------------------------------split_if_with_blocks--------------------------- | |
| 1035 // Check for aggressive application of 'split-if' optimization, | |
| 1036 // using basic block level info. | |
| 1037 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { | |
| 1038 Node *n = C->root(); | |
| 1039 visited.set(n->_idx); // first, mark node as visited | |
| 1040 // Do pre-visit work for root | |
| 1041 n = split_if_with_blocks_pre( n ); | |
| 1042 uint cnt = n->outcnt(); | |
| 1043 uint i = 0; | |
| 1044 while (true) { | |
| 1045 // Visit all children | |
| 1046 if (i < cnt) { | |
| 1047 Node* use = n->raw_out(i); | |
| 1048 ++i; | |
| 1049 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { | |
| 1050 // Now do pre-visit work for this use | |
| 1051 use = split_if_with_blocks_pre( use ); | |
| 1052 nstack.push(n, i); // Save parent and next use's index. | |
| 1053 n = use; // Process all children of current use. | |
| 1054 cnt = use->outcnt(); | |
| 1055 i = 0; | |
| 1056 } | |
| 1057 } | |
| 1058 else { | |
| 1059 // All of n's children have been processed, complete post-processing. | |
| 1060 if (cnt != 0 && !n->is_Con()) { | |
| 1061 assert(has_node(n), "no dead nodes"); | |
| 1062 split_if_with_blocks_post( n ); | |
| 1063 } | |
| 1064 if (nstack.is_empty()) { | |
| 1065 // Finished all nodes on stack. | |
| 1066 break; | |
| 1067 } | |
| 1068 // Get saved parent node and next use's index. Visit the rest of uses. | |
| 1069 n = nstack.node(); | |
| 1070 cnt = n->outcnt(); | |
| 1071 i = nstack.index(); | |
| 1072 nstack.pop(); | |
| 1073 } | |
| 1074 } | |
| 1075 } | |
| 1076 | |
| 1077 | |
| 1078 //============================================================================= | |
| 1079 // | |
| 1080 // C L O N E A L O O P B O D Y | |
| 1081 // | |
| 1082 | |
| 1083 //------------------------------clone_iff-------------------------------------- | |
| 1084 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
| 1085 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
| 1086 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
| 1087 // through the Phi recursively, and return a Bool. | |
| 1088 BoolNode *PhaseIdealLoop::clone_iff( PhiNode *phi, IdealLoopTree *loop ) { | |
| 1089 | |
| 1090 // Convert this Phi into a Phi merging Bools | |
| 1091 uint i; | |
| 1092 for( i = 1; i < phi->req(); i++ ) { | |
| 1093 Node *b = phi->in(i); | |
| 1094 if( b->is_Phi() ) { | |
| 1095 _igvn.replace_input_of(phi, i, clone_iff( b->as_Phi(), loop )); | |
| 1096 } else { | |
| 1097 assert( b->is_Bool(), "" ); | |
| 1098 } | |
| 1099 } | |
| 1100 | |
| 1101 Node *sample_bool = phi->in(1); | |
| 1102 Node *sample_cmp = sample_bool->in(1); | |
| 1103 | |
| 1104 // Make Phis to merge the Cmp's inputs. | |
| 1105 PhiNode *phi1 = new (C) PhiNode( phi->in(0), Type::TOP ); | |
| 1106 PhiNode *phi2 = new (C) PhiNode( phi->in(0), Type::TOP ); | |
| 1107 for( i = 1; i < phi->req(); i++ ) { | |
| 1108 Node *n1 = phi->in(i)->in(1)->in(1); | |
| 1109 Node *n2 = phi->in(i)->in(1)->in(2); | |
| 1110 phi1->set_req( i, n1 ); | |
| 1111 phi2->set_req( i, n2 ); | |
| 1112 phi1->set_type( phi1->type()->meet_speculative(n1->bottom_type())); | |
| 1113 phi2->set_type( phi2->type()->meet_speculative(n2->bottom_type())); | |
| 1114 } | |
| 1115 // See if these Phis have been made before. | |
| 1116 // Register with optimizer | |
| 1117 Node *hit1 = _igvn.hash_find_insert(phi1); | |
| 1118 if( hit1 ) { // Hit, toss just made Phi | |
| 1119 _igvn.remove_dead_node(phi1); // Remove new phi | |
| 1120 assert( hit1->is_Phi(), "" ); | |
| 1121 phi1 = (PhiNode*)hit1; // Use existing phi | |
| 1122 } else { // Miss | |
| 1123 _igvn.register_new_node_with_optimizer(phi1); | |
| 1124 } | |
| 1125 Node *hit2 = _igvn.hash_find_insert(phi2); | |
| 1126 if( hit2 ) { // Hit, toss just made Phi | |
| 1127 _igvn.remove_dead_node(phi2); // Remove new phi | |
| 1128 assert( hit2->is_Phi(), "" ); | |
| 1129 phi2 = (PhiNode*)hit2; // Use existing phi | |
| 1130 } else { // Miss | |
| 1131 _igvn.register_new_node_with_optimizer(phi2); | |
| 1132 } | |
| 1133 // Register Phis with loop/block info | |
| 1134 set_ctrl(phi1, phi->in(0)); | |
| 1135 set_ctrl(phi2, phi->in(0)); | |
| 1136 // Make a new Cmp | |
| 1137 Node *cmp = sample_cmp->clone(); | |
| 1138 cmp->set_req( 1, phi1 ); | |
| 1139 cmp->set_req( 2, phi2 ); | |
| 1140 _igvn.register_new_node_with_optimizer(cmp); | |
| 1141 set_ctrl(cmp, phi->in(0)); | |
| 1142 | |
| 1143 // Make a new Bool | |
| 1144 Node *b = sample_bool->clone(); | |
| 1145 b->set_req(1,cmp); | |
| 1146 _igvn.register_new_node_with_optimizer(b); | |
| 1147 set_ctrl(b, phi->in(0)); | |
| 1148 | |
| 1149 assert( b->is_Bool(), "" ); | |
| 1150 return (BoolNode*)b; | |
| 1151 } | |
| 1152 | |
| 1153 //------------------------------clone_bool------------------------------------- | |
| 1154 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
| 1155 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
| 1156 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
| 1157 // through the Phi recursively, and return a Bool. | |
| 1158 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { | |
| 1159 uint i; | |
| 1160 // Convert this Phi into a Phi merging Bools | |
| 1161 for( i = 1; i < phi->req(); i++ ) { | |
| 1162 Node *b = phi->in(i); | |
| 1163 if( b->is_Phi() ) { | |
| 1164 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop )); | |
| 1165 } else { | |
| 1166 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); | |
| 1167 } | |
| 1168 } | |
| 1169 | |
| 1170 Node *sample_cmp = phi->in(1); | |
| 1171 | |
| 1172 // Make Phis to merge the Cmp's inputs. | |
| 1173 PhiNode *phi1 = new (C) PhiNode( phi->in(0), Type::TOP ); | |
| 1174 PhiNode *phi2 = new (C) PhiNode( phi->in(0), Type::TOP ); | |
| 1175 for( uint j = 1; j < phi->req(); j++ ) { | |
| 1176 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP | |
| 1177 Node *n1, *n2; | |
| 1178 if( cmp_top->is_Cmp() ) { | |
| 1179 n1 = cmp_top->in(1); | |
| 1180 n2 = cmp_top->in(2); | |
| 1181 } else { | |
| 1182 n1 = n2 = cmp_top; | |
| 1183 } | |
| 1184 phi1->set_req( j, n1 ); | |
| 1185 phi2->set_req( j, n2 ); | |
| 1186 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); | |
| 1187 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); | |
| 1188 } | |
| 1189 | |
| 1190 // See if these Phis have been made before. | |
| 1191 // Register with optimizer | |
| 1192 Node *hit1 = _igvn.hash_find_insert(phi1); | |
| 1193 if( hit1 ) { // Hit, toss just made Phi | |
| 1194 _igvn.remove_dead_node(phi1); // Remove new phi | |
| 1195 assert( hit1->is_Phi(), "" ); | |
| 1196 phi1 = (PhiNode*)hit1; // Use existing phi | |
| 1197 } else { // Miss | |
| 1198 _igvn.register_new_node_with_optimizer(phi1); | |
| 1199 } | |
| 1200 Node *hit2 = _igvn.hash_find_insert(phi2); | |
| 1201 if( hit2 ) { // Hit, toss just made Phi | |
| 1202 _igvn.remove_dead_node(phi2); // Remove new phi | |
| 1203 assert( hit2->is_Phi(), "" ); | |
| 1204 phi2 = (PhiNode*)hit2; // Use existing phi | |
| 1205 } else { // Miss | |
| 1206 _igvn.register_new_node_with_optimizer(phi2); | |
| 1207 } | |
| 1208 // Register Phis with loop/block info | |
| 1209 set_ctrl(phi1, phi->in(0)); | |
| 1210 set_ctrl(phi2, phi->in(0)); | |
| 1211 // Make a new Cmp | |
| 1212 Node *cmp = sample_cmp->clone(); | |
| 1213 cmp->set_req( 1, phi1 ); | |
| 1214 cmp->set_req( 2, phi2 ); | |
| 1215 _igvn.register_new_node_with_optimizer(cmp); | |
| 1216 set_ctrl(cmp, phi->in(0)); | |
| 1217 | |
| 1218 assert( cmp->is_Cmp(), "" ); | |
| 1219 return (CmpNode*)cmp; | |
| 1220 } | |
| 1221 | |
| 1222 //------------------------------sink_use--------------------------------------- | |
| 1223 // If 'use' was in the loop-exit block, it now needs to be sunk | |
| 1224 // below the post-loop merge point. | |
| 1225 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { | |
| 1226 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { | |
| 1227 set_ctrl(use, post_loop); | |
| 1228 for (DUIterator j = use->outs(); use->has_out(j); j++) | |
| 1229 sink_use(use->out(j), post_loop); | |
| 1230 } | |
| 1231 } | |
| 1232 | |
| 1233 //------------------------------clone_loop------------------------------------- | |
| 1234 // | |
| 1235 // C L O N E A L O O P B O D Y | |
| 1236 // | |
| 1237 // This is the basic building block of the loop optimizations. It clones an | |
| 1238 // entire loop body. It makes an old_new loop body mapping; with this mapping | |
| 1239 // you can find the new-loop equivalent to an old-loop node. All new-loop | |
| 1240 // nodes are exactly equal to their old-loop counterparts, all edges are the | |
| 1241 // same. All exits from the old-loop now have a RegionNode that merges the | |
| 1242 // equivalent new-loop path. This is true even for the normal "loop-exit" | |
| 1243 // condition. All uses of loop-invariant old-loop values now come from (one | |
| 1244 // or more) Phis that merge their new-loop equivalents. | |
| 1245 // | |
| 1246 // This operation leaves the graph in an illegal state: there are two valid | |
| 1247 // control edges coming from the loop pre-header to both loop bodies. I'll | |
| 1248 // definitely have to hack the graph after running this transform. | |
| 1249 // | |
| 1250 // From this building block I will further edit edges to perform loop peeling | |
| 1251 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. | |
| 1252 // | |
| 1253 // Parameter side_by_size_idom: | |
| 1254 // When side_by_size_idom is NULL, the dominator tree is constructed for | |
| 1255 // the clone loop to dominate the original. Used in construction of | |
| 1256 // pre-main-post loop sequence. | |
| 1257 // When nonnull, the clone and original are side-by-side, both are | |
| 1258 // dominated by the side_by_side_idom node. Used in construction of | |
| 1259 // unswitched loops. | |
| 1260 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, | |
| 1261 Node* side_by_side_idom) { | |
| 1262 | |
| 1263 // Step 1: Clone the loop body. Make the old->new mapping. | |
| 1264 uint i; | |
| 1265 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1266 Node *old = loop->_body.at(i); | |
| 1267 Node *nnn = old->clone(); | |
| 1268 old_new.map( old->_idx, nnn ); | |
| 1269 _igvn.register_new_node_with_optimizer(nnn); | |
| 1270 } | |
| 1271 | |
| 1272 | |
| 1273 // Step 2: Fix the edges in the new body. If the old input is outside the | |
| 1274 // loop use it. If the old input is INside the loop, use the corresponding | |
| 1275 // new node instead. | |
| 1276 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1277 Node *old = loop->_body.at(i); | |
| 1278 Node *nnn = old_new[old->_idx]; | |
| 1279 // Fix CFG/Loop controlling the new node | |
| 1280 if (has_ctrl(old)) { | |
| 1281 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); | |
| 1282 } else { | |
| 1283 set_loop(nnn, loop->_parent); | |
| 1284 if (old->outcnt() > 0) { | |
| 1285 set_idom( nnn, old_new[idom(old)->_idx], dd ); | |
| 1286 } | |
| 1287 } | |
| 1288 // Correct edges to the new node | |
| 1289 for( uint j = 0; j < nnn->req(); j++ ) { | |
| 1290 Node *n = nnn->in(j); | |
| 1291 if( n ) { | |
| 1292 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); | |
| 1293 if( loop->is_member( old_in_loop ) ) | |
| 1294 nnn->set_req(j, old_new[n->_idx]); | |
| 1295 } | |
| 1296 } | |
| 1297 _igvn.hash_find_insert(nnn); | |
| 1298 } | |
| 1299 Node *newhead = old_new[loop->_head->_idx]; | |
| 1300 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); | |
| 1301 | |
| 1302 | |
| 1303 // Step 3: Now fix control uses. Loop varying control uses have already | |
| 1304 // been fixed up (as part of all input edges in Step 2). Loop invariant | |
| 1305 // control uses must be either an IfFalse or an IfTrue. Make a merge | |
| 1306 // point to merge the old and new IfFalse/IfTrue nodes; make the use | |
| 1307 // refer to this. | |
| 1308 ResourceArea *area = Thread::current()->resource_area(); | |
| 1309 Node_List worklist(area); | |
| 1310 uint new_counter = C->unique(); | |
| 1311 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1312 Node* old = loop->_body.at(i); | |
| 1313 if( !old->is_CFG() ) continue; | |
| 1314 Node* nnn = old_new[old->_idx]; | |
| 1315 | |
| 1316 // Copy uses to a worklist, so I can munge the def-use info | |
| 1317 // with impunity. | |
| 1318 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
| 1319 worklist.push(old->fast_out(j)); | |
| 1320 | |
| 1321 while( worklist.size() ) { // Visit all uses | |
| 1322 Node *use = worklist.pop(); | |
| 1323 if (!has_node(use)) continue; // Ignore dead nodes | |
| 1324 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
| 1325 if( !loop->is_member( use_loop ) && use->is_CFG() ) { | |
| 1326 // Both OLD and USE are CFG nodes here. | |
| 1327 assert( use->is_Proj(), "" ); | |
| 1328 | |
| 1329 // Clone the loop exit control projection | |
| 1330 Node *newuse = use->clone(); | |
| 1331 newuse->set_req(0,nnn); | |
| 1332 _igvn.register_new_node_with_optimizer(newuse); | |
| 1333 set_loop(newuse, use_loop); | |
| 1334 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); | |
| 1335 | |
| 1336 // We need a Region to merge the exit from the peeled body and the | |
| 1337 // exit from the old loop body. | |
| 1338 RegionNode *r = new (C) RegionNode(3); | |
| 1339 // Map the old use to the new merge point | |
| 1340 old_new.map( use->_idx, r ); | |
| 1341 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); | |
| 1342 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); | |
| 1343 | |
| 1344 // The original user of 'use' uses 'r' instead. | |
| 1345 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { | |
| 1346 Node* useuse = use->last_out(l); | |
| 1347 _igvn.rehash_node_delayed(useuse); | |
| 1348 uint uses_found = 0; | |
| 1349 if( useuse->in(0) == use ) { | |
| 1350 useuse->set_req(0, r); | |
| 1351 uses_found++; | |
| 1352 if( useuse->is_CFG() ) { | |
| 1353 assert( dom_depth(useuse) > dd_r, "" ); | |
| 1354 set_idom(useuse, r, dom_depth(useuse)); | |
| 1355 } | |
| 1356 } | |
| 1357 for( uint k = 1; k < useuse->req(); k++ ) { | |
| 1358 if( useuse->in(k) == use ) { | |
| 1359 useuse->set_req(k, r); | |
| 1360 uses_found++; | |
| 1361 } | |
| 1362 } | |
| 1363 l -= uses_found; // we deleted 1 or more copies of this edge | |
| 1364 } | |
| 1365 | |
| 1366 // Now finish up 'r' | |
| 1367 r->set_req( 1, newuse ); | |
| 1368 r->set_req( 2, use ); | |
| 1369 _igvn.register_new_node_with_optimizer(r); | |
| 1370 set_loop(r, use_loop); | |
| 1371 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); | |
| 1372 } // End of if a loop-exit test | |
| 1373 } | |
| 1374 } | |
| 1375 | |
| 1376 // Step 4: If loop-invariant use is not control, it must be dominated by a | |
| 1377 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region | |
| 1378 // there if needed. Make a Phi there merging old and new used values. | |
| 1379 Node_List *split_if_set = NULL; | |
| 1380 Node_List *split_bool_set = NULL; | |
| 1381 Node_List *split_cex_set = NULL; | |
| 1382 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1383 Node* old = loop->_body.at(i); | |
| 1384 Node* nnn = old_new[old->_idx]; | |
| 1385 // Copy uses to a worklist, so I can munge the def-use info | |
| 1386 // with impunity. | |
| 1387 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
| 1388 worklist.push(old->fast_out(j)); | |
| 1389 | |
| 1390 while( worklist.size() ) { | |
| 1391 Node *use = worklist.pop(); | |
| 1392 if (!has_node(use)) continue; // Ignore dead nodes | |
| 1393 if (use->in(0) == C->top()) continue; | |
| 1394 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
| 1395 // Check for data-use outside of loop - at least one of OLD or USE | |
| 1396 // must not be a CFG node. | |
| 1397 if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { | |
| 1398 | |
| 1399 // If the Data use is an IF, that means we have an IF outside of the | |
| 1400 // loop that is switching on a condition that is set inside of the | |
| 1401 // loop. Happens if people set a loop-exit flag; then test the flag | |
| 1402 // in the loop to break the loop, then test is again outside of the | |
| 1403 // loop to determine which way the loop exited. | |
| 1404 // Loop predicate If node connects to Bool node through Opaque1 node. | |
| 1405 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use)) { | |
| 1406 // Since this code is highly unlikely, we lazily build the worklist | |
| 1407 // of such Nodes to go split. | |
| 1408 if( !split_if_set ) | |
| 1409 split_if_set = new Node_List(area); | |
| 1410 split_if_set->push(use); | |
| 1411 } | |
| 1412 if( use->is_Bool() ) { | |
| 1413 if( !split_bool_set ) | |
| 1414 split_bool_set = new Node_List(area); | |
| 1415 split_bool_set->push(use); | |
| 1416 } | |
| 1417 if( use->Opcode() == Op_CreateEx ) { | |
| 1418 if( !split_cex_set ) | |
| 1419 split_cex_set = new Node_List(area); | |
| 1420 split_cex_set->push(use); | |
| 1421 } | |
| 1422 | |
| 1423 | |
| 1424 // Get "block" use is in | |
| 1425 uint idx = 0; | |
| 1426 while( use->in(idx) != old ) idx++; | |
| 1427 Node *prev = use->is_CFG() ? use : get_ctrl(use); | |
| 1428 assert( !loop->is_member( get_loop( prev ) ), "" ); | |
| 1429 Node *cfg = prev->_idx >= new_counter | |
| 1430 ? prev->in(2) | |
| 1431 : idom(prev); | |
| 1432 if( use->is_Phi() ) // Phi use is in prior block | |
| 1433 cfg = prev->in(idx); // NOT in block of Phi itself | |
| 1434 if (cfg->is_top()) { // Use is dead? | |
| 1435 _igvn.replace_input_of(use, idx, C->top()); | |
| 1436 continue; | |
| 1437 } | |
| 1438 | |
| 1439 while( !loop->is_member( get_loop( cfg ) ) ) { | |
| 1440 prev = cfg; | |
| 1441 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); | |
| 1442 } | |
| 1443 // If the use occurs after merging several exits from the loop, then | |
| 1444 // old value must have dominated all those exits. Since the same old | |
| 1445 // value was used on all those exits we did not need a Phi at this | |
| 1446 // merge point. NOW we do need a Phi here. Each loop exit value | |
| 1447 // is now merged with the peeled body exit; each exit gets its own | |
| 1448 // private Phi and those Phis need to be merged here. | |
| 1449 Node *phi; | |
| 1450 if( prev->is_Region() ) { | |
| 1451 if( idx == 0 ) { // Updating control edge? | |
| 1452 phi = prev; // Just use existing control | |
| 1453 } else { // Else need a new Phi | |
| 1454 phi = PhiNode::make( prev, old ); | |
| 1455 // Now recursively fix up the new uses of old! | |
| 1456 for( uint i = 1; i < prev->req(); i++ ) { | |
| 1457 worklist.push(phi); // Onto worklist once for each 'old' input | |
| 1458 } | |
| 1459 } | |
| 1460 } else { | |
| 1461 // Get new RegionNode merging old and new loop exits | |
| 1462 prev = old_new[prev->_idx]; | |
| 1463 assert( prev, "just made this in step 7" ); | |
| 1464 if( idx == 0 ) { // Updating control edge? | |
| 1465 phi = prev; // Just use existing control | |
| 1466 } else { // Else need a new Phi | |
| 1467 // Make a new Phi merging data values properly | |
| 1468 phi = PhiNode::make( prev, old ); | |
| 1469 phi->set_req( 1, nnn ); | |
| 1470 } | |
| 1471 } | |
| 1472 // If inserting a new Phi, check for prior hits | |
| 1473 if( idx != 0 ) { | |
| 1474 Node *hit = _igvn.hash_find_insert(phi); | |
| 1475 if( hit == NULL ) { | |
| 1476 _igvn.register_new_node_with_optimizer(phi); // Register new phi | |
| 1477 } else { // or | |
| 1478 // Remove the new phi from the graph and use the hit | |
| 1479 _igvn.remove_dead_node(phi); | |
| 1480 phi = hit; // Use existing phi | |
| 1481 } | |
| 1482 set_ctrl(phi, prev); | |
| 1483 } | |
| 1484 // Make 'use' use the Phi instead of the old loop body exit value | |
| 1485 _igvn.replace_input_of(use, idx, phi); | |
| 1486 if( use->_idx >= new_counter ) { // If updating new phis | |
| 1487 // Not needed for correctness, but prevents a weak assert | |
| 1488 // in AddPNode from tripping (when we end up with different | |
| 1489 // base & derived Phis that will become the same after | |
| 1490 // IGVN does CSE). | |
| 1491 Node *hit = _igvn.hash_find_insert(use); | |
| 1492 if( hit ) // Go ahead and re-hash for hits. | |
| 1493 _igvn.replace_node( use, hit ); | |
| 1494 } | |
| 1495 | |
| 1496 // If 'use' was in the loop-exit block, it now needs to be sunk | |
| 1497 // below the post-loop merge point. | |
| 1498 sink_use( use, prev ); | |
| 1499 } | |
| 1500 } | |
| 1501 } | |
| 1502 | |
| 1503 // Check for IFs that need splitting/cloning. Happens if an IF outside of | |
| 1504 // the loop uses a condition set in the loop. The original IF probably | |
| 1505 // takes control from one or more OLD Regions (which in turn get from NEW | |
| 1506 // Regions). In any case, there will be a set of Phis for each merge point | |
| 1507 // from the IF up to where the original BOOL def exists the loop. | |
| 1508 if( split_if_set ) { | |
| 1509 while( split_if_set->size() ) { | |
| 1510 Node *iff = split_if_set->pop(); | |
| 1511 if( iff->in(1)->is_Phi() ) { | |
| 1512 BoolNode *b = clone_iff( iff->in(1)->as_Phi(), loop ); | |
| 1513 _igvn.replace_input_of(iff, 1, b); | |
| 1514 } | |
| 1515 } | |
| 1516 } | |
| 1517 if( split_bool_set ) { | |
| 1518 while( split_bool_set->size() ) { | |
| 1519 Node *b = split_bool_set->pop(); | |
| 1520 Node *phi = b->in(1); | |
| 1521 assert( phi->is_Phi(), "" ); | |
| 1522 CmpNode *cmp = clone_bool( (PhiNode*)phi, loop ); | |
| 1523 _igvn.replace_input_of(b, 1, cmp); | |
| 1524 } | |
| 1525 } | |
| 1526 if( split_cex_set ) { | |
| 1527 while( split_cex_set->size() ) { | |
| 1528 Node *b = split_cex_set->pop(); | |
| 1529 assert( b->in(0)->is_Region(), "" ); | |
| 1530 assert( b->in(1)->is_Phi(), "" ); | |
| 1531 assert( b->in(0)->in(0) == b->in(1)->in(0), "" ); | |
| 1532 split_up( b, b->in(0), NULL ); | |
| 1533 } | |
| 1534 } | |
| 1535 | |
| 1536 } | |
| 1537 | |
| 1538 | |
| 1539 //---------------------- stride_of_possible_iv ------------------------------------- | |
| 1540 // Looks for an iff/bool/comp with one operand of the compare | |
| 1541 // being a cycle involving an add and a phi, | |
| 1542 // with an optional truncation (left-shift followed by a right-shift) | |
| 1543 // of the add. Returns zero if not an iv. | |
| 1544 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { | |
| 1545 Node* trunc1 = NULL; | |
| 1546 Node* trunc2 = NULL; | |
| 1547 const TypeInt* ttype = NULL; | |
| 1548 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { | |
| 1549 return 0; | |
| 1550 } | |
| 1551 BoolNode* bl = iff->in(1)->as_Bool(); | |
| 1552 Node* cmp = bl->in(1); | |
| 1553 if (!cmp || cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU) { | |
| 1554 return 0; | |
| 1555 } | |
| 1556 // Must have an invariant operand | |
| 1557 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { | |
| 1558 return 0; | |
| 1559 } | |
| 1560 Node* add2 = NULL; | |
| 1561 Node* cmp1 = cmp->in(1); | |
| 1562 if (cmp1->is_Phi()) { | |
| 1563 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) | |
| 1564 Node* phi = cmp1; | |
| 1565 for (uint i = 1; i < phi->req(); i++) { | |
| 1566 Node* in = phi->in(i); | |
| 1567 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, | |
| 1568 &trunc1, &trunc2, &ttype); | |
| 1569 if (add && add->in(1) == phi) { | |
| 1570 add2 = add->in(2); | |
| 1571 break; | |
| 1572 } | |
| 1573 } | |
| 1574 } else { | |
| 1575 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) | |
| 1576 Node* addtrunc = cmp1; | |
| 1577 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, | |
| 1578 &trunc1, &trunc2, &ttype); | |
| 1579 if (add && add->in(1)->is_Phi()) { | |
| 1580 Node* phi = add->in(1); | |
| 1581 for (uint i = 1; i < phi->req(); i++) { | |
| 1582 if (phi->in(i) == addtrunc) { | |
| 1583 add2 = add->in(2); | |
| 1584 break; | |
| 1585 } | |
| 1586 } | |
| 1587 } | |
| 1588 } | |
| 1589 if (add2 != NULL) { | |
| 1590 const TypeInt* add2t = _igvn.type(add2)->is_int(); | |
| 1591 if (add2t->is_con()) { | |
| 1592 return add2t->get_con(); | |
| 1593 } | |
| 1594 } | |
| 1595 return 0; | |
| 1596 } | |
| 1597 | |
| 1598 | |
| 1599 //---------------------- stay_in_loop ------------------------------------- | |
| 1600 // Return the (unique) control output node that's in the loop (if it exists.) | |
| 1601 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { | |
| 1602 Node* unique = NULL; | |
| 1603 if (!n) return NULL; | |
| 1604 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { | |
| 1605 Node* use = n->fast_out(i); | |
| 1606 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { | |
| 1607 if (unique != NULL) { | |
| 1608 return NULL; | |
| 1609 } | |
| 1610 unique = use; | |
| 1611 } | |
| 1612 } | |
| 1613 return unique; | |
| 1614 } | |
| 1615 | |
| 1616 //------------------------------ register_node ------------------------------------- | |
| 1617 // Utility to register node "n" with PhaseIdealLoop | |
| 1618 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { | |
| 1619 _igvn.register_new_node_with_optimizer(n); | |
| 1620 loop->_body.push(n); | |
| 1621 if (n->is_CFG()) { | |
| 1622 set_loop(n, loop); | |
| 1623 set_idom(n, pred, ddepth); | |
| 1624 } else { | |
| 1625 set_ctrl(n, pred); | |
| 1626 } | |
| 1627 } | |
| 1628 | |
| 1629 //------------------------------ proj_clone ------------------------------------- | |
| 1630 // Utility to create an if-projection | |
| 1631 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { | |
| 1632 ProjNode* c = p->clone()->as_Proj(); | |
| 1633 c->set_req(0, iff); | |
| 1634 return c; | |
| 1635 } | |
| 1636 | |
| 1637 //------------------------------ short_circuit_if ------------------------------------- | |
| 1638 // Force the iff control output to be the live_proj | |
| 1639 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { | |
| 1640 guarantee(live_proj != NULL, "null projection"); | |
| 1641 int proj_con = live_proj->_con; | |
| 1642 assert(proj_con == 0 || proj_con == 1, "false or true projection"); | |
| 1643 Node *con = _igvn.intcon(proj_con); | |
| 1644 set_ctrl(con, C->root()); | |
| 1645 if (iff) { | |
| 1646 iff->set_req(1, con); | |
| 1647 } | |
| 1648 return con; | |
| 1649 } | |
| 1650 | |
| 1651 //------------------------------ insert_if_before_proj ------------------------------------- | |
| 1652 // Insert a new if before an if projection (* - new node) | |
| 1653 // | |
| 1654 // before | |
| 1655 // if(test) | |
| 1656 // / \ | |
| 1657 // v v | |
| 1658 // other-proj proj (arg) | |
| 1659 // | |
| 1660 // after | |
| 1661 // if(test) | |
| 1662 // / \ | |
| 1663 // / v | |
| 1664 // | * proj-clone | |
| 1665 // v | | |
| 1666 // other-proj v | |
| 1667 // * new_if(relop(cmp[IU](left,right))) | |
| 1668 // / \ | |
| 1669 // v v | |
| 1670 // * new-proj proj | |
| 1671 // (returned) | |
| 1672 // | |
| 1673 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { | |
| 1674 IfNode* iff = proj->in(0)->as_If(); | |
| 1675 IdealLoopTree *loop = get_loop(proj); | |
| 1676 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
| 1677 int ddepth = dom_depth(proj); | |
| 1678 | |
| 1679 _igvn.rehash_node_delayed(iff); | |
| 1680 _igvn.rehash_node_delayed(proj); | |
| 1681 | |
| 1682 proj->set_req(0, NULL); // temporary disconnect | |
| 1683 ProjNode* proj2 = proj_clone(proj, iff); | |
| 1684 register_node(proj2, loop, iff, ddepth); | |
| 1685 | |
| 1686 Node* cmp = Signed ? (Node*) new (C)CmpINode(left, right) : (Node*) new (C)CmpUNode(left, right); | |
| 1687 register_node(cmp, loop, proj2, ddepth); | |
| 1688 | |
| 1689 BoolNode* bol = new (C)BoolNode(cmp, relop); | |
| 1690 register_node(bol, loop, proj2, ddepth); | |
| 1691 | |
| 1692 IfNode* new_if = new (C)IfNode(proj2, bol, iff->_prob, iff->_fcnt); | |
| 1693 register_node(new_if, loop, proj2, ddepth); | |
| 1694 | |
| 1695 proj->set_req(0, new_if); // reattach | |
| 1696 set_idom(proj, new_if, ddepth); | |
| 1697 | |
| 1698 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); | |
| 1699 guarantee(new_exit != NULL, "null exit node"); | |
| 1700 register_node(new_exit, get_loop(other_proj), new_if, ddepth); | |
| 1701 | |
| 1702 return new_exit; | |
| 1703 } | |
| 1704 | |
| 1705 //------------------------------ insert_region_before_proj ------------------------------------- | |
| 1706 // Insert a region before an if projection (* - new node) | |
| 1707 // | |
| 1708 // before | |
| 1709 // if(test) | |
| 1710 // / | | |
| 1711 // v | | |
| 1712 // proj v | |
| 1713 // other-proj | |
| 1714 // | |
| 1715 // after | |
| 1716 // if(test) | |
| 1717 // / | | |
| 1718 // v | | |
| 1719 // * proj-clone v | |
| 1720 // | other-proj | |
| 1721 // v | |
| 1722 // * new-region | |
| 1723 // | | |
| 1724 // v | |
| 1725 // * dum_if | |
| 1726 // / \ | |
| 1727 // v \ | |
| 1728 // * dum-proj v | |
| 1729 // proj | |
| 1730 // | |
| 1731 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { | |
| 1732 IfNode* iff = proj->in(0)->as_If(); | |
| 1733 IdealLoopTree *loop = get_loop(proj); | |
| 1734 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
| 1735 int ddepth = dom_depth(proj); | |
| 1736 | |
| 1737 _igvn.rehash_node_delayed(iff); | |
| 1738 _igvn.rehash_node_delayed(proj); | |
| 1739 | |
| 1740 proj->set_req(0, NULL); // temporary disconnect | |
| 1741 ProjNode* proj2 = proj_clone(proj, iff); | |
| 1742 register_node(proj2, loop, iff, ddepth); | |
| 1743 | |
| 1744 RegionNode* reg = new (C)RegionNode(2); | |
| 1745 reg->set_req(1, proj2); | |
| 1746 register_node(reg, loop, iff, ddepth); | |
| 1747 | |
| 1748 IfNode* dum_if = new (C)IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); | |
| 1749 register_node(dum_if, loop, reg, ddepth); | |
| 1750 | |
| 1751 proj->set_req(0, dum_if); // reattach | |
| 1752 set_idom(proj, dum_if, ddepth); | |
| 1753 | |
| 1754 ProjNode* dum_proj = proj_clone(other_proj, dum_if); | |
| 1755 register_node(dum_proj, loop, dum_if, ddepth); | |
| 1756 | |
| 1757 return reg; | |
| 1758 } | |
| 1759 | |
| 1760 //------------------------------ insert_cmpi_loop_exit ------------------------------------- | |
| 1761 // Clone a signed compare loop exit from an unsigned compare and | |
| 1762 // insert it before the unsigned cmp on the stay-in-loop path. | |
| 1763 // All new nodes inserted in the dominator tree between the original | |
| 1764 // if and it's projections. The original if test is replaced with | |
| 1765 // a constant to force the stay-in-loop path. | |
| 1766 // | |
| 1767 // This is done to make sure that the original if and it's projections | |
| 1768 // still dominate the same set of control nodes, that the ctrl() relation | |
| 1769 // from data nodes to them is preserved, and that their loop nesting is | |
| 1770 // preserved. | |
| 1771 // | |
| 1772 // before | |
| 1773 // if(i <u limit) unsigned compare loop exit | |
| 1774 // / | | |
| 1775 // v v | |
| 1776 // exit-proj stay-in-loop-proj | |
| 1777 // | |
| 1778 // after | |
| 1779 // if(stay-in-loop-const) original if | |
| 1780 // / | | |
| 1781 // / v | |
| 1782 // / if(i < limit) new signed test | |
| 1783 // / / | | |
| 1784 // / / v | |
| 1785 // / / if(i <u limit) new cloned unsigned test | |
| 1786 // / / / | | |
| 1787 // v v v | | |
| 1788 // region | | |
| 1789 // | | | |
| 1790 // dum-if | | |
| 1791 // / | | | |
| 1792 // ether | | | |
| 1793 // v v | |
| 1794 // exit-proj stay-in-loop-proj | |
| 1795 // | |
| 1796 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { | |
| 1797 const bool Signed = true; | |
| 1798 const bool Unsigned = false; | |
| 1799 | |
| 1800 BoolNode* bol = if_cmpu->in(1)->as_Bool(); | |
| 1801 if (bol->_test._test != BoolTest::lt) return NULL; | |
| 1802 CmpNode* cmpu = bol->in(1)->as_Cmp(); | |
| 1803 if (cmpu->Opcode() != Op_CmpU) return NULL; | |
| 1804 int stride = stride_of_possible_iv(if_cmpu); | |
| 1805 if (stride == 0) return NULL; | |
| 1806 | |
| 1807 Node* lp_proj = stay_in_loop(if_cmpu, loop); | |
| 1808 guarantee(lp_proj != NULL, "null loop node"); | |
| 1809 | |
| 1810 ProjNode* lp_continue = lp_proj->as_Proj(); | |
| 1811 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); | |
| 1812 | |
| 1813 Node* limit = NULL; | |
| 1814 if (stride > 0) { | |
| 1815 limit = cmpu->in(2); | |
| 1816 } else { | |
| 1817 limit = _igvn.makecon(TypeInt::ZERO); | |
| 1818 set_ctrl(limit, C->root()); | |
| 1819 } | |
| 1820 // Create a new region on the exit path | |
| 1821 RegionNode* reg = insert_region_before_proj(lp_exit); | |
| 1822 guarantee(reg != NULL, "null region node"); | |
| 1823 | |
| 1824 // Clone the if-cmpu-true-false using a signed compare | |
| 1825 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; | |
| 1826 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); | |
| 1827 reg->add_req(cmpi_exit); | |
| 1828 | |
| 1829 // Clone the if-cmpu-true-false | |
| 1830 BoolTest::mask rel_u = bol->_test._test; | |
| 1831 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); | |
| 1832 reg->add_req(cmpu_exit); | |
| 1833 | |
| 1834 // Force original if to stay in loop. | |
| 1835 short_circuit_if(if_cmpu, lp_continue); | |
| 1836 | |
| 1837 return cmpi_exit->in(0)->as_If(); | |
| 1838 } | |
| 1839 | |
| 1840 //------------------------------ remove_cmpi_loop_exit ------------------------------------- | |
| 1841 // Remove a previously inserted signed compare loop exit. | |
| 1842 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { | |
| 1843 Node* lp_proj = stay_in_loop(if_cmp, loop); | |
| 1844 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && | |
| 1845 stay_in_loop(lp_proj, loop)->is_If() && | |
| 1846 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); | |
| 1847 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); | |
| 1848 set_ctrl(con, C->root()); | |
| 1849 if_cmp->set_req(1, con); | |
| 1850 } | |
| 1851 | |
| 1852 //------------------------------ scheduled_nodelist ------------------------------------- | |
| 1853 // Create a post order schedule of nodes that are in the | |
| 1854 // "member" set. The list is returned in "sched". | |
| 1855 // The first node in "sched" is the loop head, followed by | |
| 1856 // nodes which have no inputs in the "member" set, and then | |
| 1857 // followed by the nodes that have an immediate input dependence | |
| 1858 // on a node in "sched". | |
| 1859 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { | |
| 1860 | |
| 1861 assert(member.test(loop->_head->_idx), "loop head must be in member set"); | |
| 1862 Arena *a = Thread::current()->resource_area(); | |
| 1863 VectorSet visited(a); | |
| 1864 Node_Stack nstack(a, loop->_body.size()); | |
| 1865 | |
| 1866 Node* n = loop->_head; // top of stack is cached in "n" | |
| 1867 uint idx = 0; | |
| 1868 visited.set(n->_idx); | |
| 1869 | |
| 1870 // Initially push all with no inputs from within member set | |
| 1871 for(uint i = 0; i < loop->_body.size(); i++ ) { | |
| 1872 Node *elt = loop->_body.at(i); | |
| 1873 if (member.test(elt->_idx)) { | |
| 1874 bool found = false; | |
| 1875 for (uint j = 0; j < elt->req(); j++) { | |
| 1876 Node* def = elt->in(j); | |
| 1877 if (def && member.test(def->_idx) && def != elt) { | |
| 1878 found = true; | |
| 1879 break; | |
| 1880 } | |
| 1881 } | |
| 1882 if (!found && elt != loop->_head) { | |
| 1883 nstack.push(n, idx); | |
| 1884 n = elt; | |
| 1885 assert(!visited.test(n->_idx), "not seen yet"); | |
| 1886 visited.set(n->_idx); | |
| 1887 } | |
| 1888 } | |
| 1889 } | |
| 1890 | |
| 1891 // traverse out's that are in the member set | |
| 1892 while (true) { | |
| 1893 if (idx < n->outcnt()) { | |
| 1894 Node* use = n->raw_out(idx); | |
| 1895 idx++; | |
| 1896 if (!visited.test_set(use->_idx)) { | |
| 1897 if (member.test(use->_idx)) { | |
| 1898 nstack.push(n, idx); | |
| 1899 n = use; | |
| 1900 idx = 0; | |
| 1901 } | |
| 1902 } | |
| 1903 } else { | |
| 1904 // All outputs processed | |
| 1905 sched.push(n); | |
| 1906 if (nstack.is_empty()) break; | |
| 1907 n = nstack.node(); | |
| 1908 idx = nstack.index(); | |
| 1909 nstack.pop(); | |
| 1910 } | |
| 1911 } | |
| 1912 } | |
| 1913 | |
| 1914 | |
| 1915 //------------------------------ has_use_in_set ------------------------------------- | |
| 1916 // Has a use in the vector set | |
| 1917 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { | |
| 1918 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 1919 Node* use = n->fast_out(j); | |
| 1920 if (vset.test(use->_idx)) { | |
| 1921 return true; | |
| 1922 } | |
| 1923 } | |
| 1924 return false; | |
| 1925 } | |
| 1926 | |
| 1927 | |
| 1928 //------------------------------ has_use_internal_to_set ------------------------------------- | |
| 1929 // Has use internal to the vector set (ie. not in a phi at the loop head) | |
| 1930 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { | |
| 1931 Node* head = loop->_head; | |
| 1932 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 1933 Node* use = n->fast_out(j); | |
| 1934 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { | |
| 1935 return true; | |
| 1936 } | |
| 1937 } | |
| 1938 return false; | |
| 1939 } | |
| 1940 | |
| 1941 | |
| 1942 //------------------------------ clone_for_use_outside_loop ------------------------------------- | |
| 1943 // clone "n" for uses that are outside of loop | |
| 1944 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { | |
| 1945 int cloned = 0; | |
| 1946 assert(worklist.size() == 0, "should be empty"); | |
| 1947 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 1948 Node* use = n->fast_out(j); | |
| 1949 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { | |
| 1950 worklist.push(use); | |
| 1951 } | |
| 1952 } | |
| 1953 while( worklist.size() ) { | |
| 1954 Node *use = worklist.pop(); | |
| 1955 if (!has_node(use) || use->in(0) == C->top()) continue; | |
| 1956 uint j; | |
| 1957 for (j = 0; j < use->req(); j++) { | |
| 1958 if (use->in(j) == n) break; | |
| 1959 } | |
| 1960 assert(j < use->req(), "must be there"); | |
| 1961 | |
| 1962 // clone "n" and insert it between the inputs of "n" and the use outside the loop | |
| 1963 Node* n_clone = n->clone(); | |
| 1964 _igvn.replace_input_of(use, j, n_clone); | |
| 1965 cloned++; | |
| 1966 Node* use_c; | |
| 1967 if (!use->is_Phi()) { | |
| 1968 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); | |
| 1969 } else { | |
| 1970 // Use in a phi is considered a use in the associated predecessor block | |
| 1971 use_c = use->in(0)->in(j); | |
| 1972 } | |
| 1973 set_ctrl(n_clone, use_c); | |
| 1974 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); | |
| 1975 get_loop(use_c)->_body.push(n_clone); | |
| 1976 _igvn.register_new_node_with_optimizer(n_clone); | |
| 1977 #if !defined(PRODUCT) | |
| 1978 if (TracePartialPeeling) { | |
| 1979 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); | |
| 1980 } | |
| 1981 #endif | |
| 1982 } | |
| 1983 return cloned; | |
| 1984 } | |
| 1985 | |
| 1986 | |
| 1987 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- | |
| 1988 // clone "n" for special uses that are in the not_peeled region. | |
| 1989 // If these def-uses occur in separate blocks, the code generator | |
| 1990 // marks the method as not compilable. For example, if a "BoolNode" | |
| 1991 // is in a different basic block than the "IfNode" that uses it, then | |
| 1992 // the compilation is aborted in the code generator. | |
| 1993 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, | |
| 1994 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { | |
| 1995 if (n->is_Phi() || n->is_Load()) { | |
| 1996 return; | |
| 1997 } | |
| 1998 assert(worklist.size() == 0, "should be empty"); | |
| 1999 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 2000 Node* use = n->fast_out(j); | |
| 2001 if ( not_peel.test(use->_idx) && | |
| 2002 (use->is_If() || use->is_CMove() || use->is_Bool()) && | |
| 2003 use->in(1) == n) { | |
| 2004 worklist.push(use); | |
| 2005 } | |
| 2006 } | |
| 2007 if (worklist.size() > 0) { | |
| 2008 // clone "n" and insert it between inputs of "n" and the use | |
| 2009 Node* n_clone = n->clone(); | |
| 2010 loop->_body.push(n_clone); | |
| 2011 _igvn.register_new_node_with_optimizer(n_clone); | |
| 2012 set_ctrl(n_clone, get_ctrl(n)); | |
| 2013 sink_list.push(n_clone); | |
| 2014 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. | |
| 2015 #if !defined(PRODUCT) | |
| 2016 if (TracePartialPeeling) { | |
| 2017 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); | |
| 2018 } | |
| 2019 #endif | |
| 2020 while( worklist.size() ) { | |
| 2021 Node *use = worklist.pop(); | |
| 2022 _igvn.rehash_node_delayed(use); | |
| 2023 for (uint j = 1; j < use->req(); j++) { | |
| 2024 if (use->in(j) == n) { | |
| 2025 use->set_req(j, n_clone); | |
| 2026 } | |
| 2027 } | |
| 2028 } | |
| 2029 } | |
| 2030 } | |
| 2031 | |
| 2032 | |
| 2033 //------------------------------ insert_phi_for_loop ------------------------------------- | |
| 2034 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist | |
| 2035 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { | |
| 2036 Node *phi = PhiNode::make(lp, back_edge_val); | |
| 2037 phi->set_req(LoopNode::EntryControl, lp_entry_val); | |
| 2038 // Use existing phi if it already exists | |
| 2039 Node *hit = _igvn.hash_find_insert(phi); | |
| 2040 if( hit == NULL ) { | |
| 2041 _igvn.register_new_node_with_optimizer(phi); | |
| 2042 set_ctrl(phi, lp); | |
| 2043 } else { | |
| 2044 // Remove the new phi from the graph and use the hit | |
| 2045 _igvn.remove_dead_node(phi); | |
| 2046 phi = hit; | |
| 2047 } | |
| 2048 _igvn.replace_input_of(use, idx, phi); | |
| 2049 } | |
| 2050 | |
| 2051 #ifdef ASSERT | |
| 2052 //------------------------------ is_valid_loop_partition ------------------------------------- | |
| 2053 // Validate the loop partition sets: peel and not_peel | |
| 2054 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, | |
| 2055 VectorSet& not_peel ) { | |
| 2056 uint i; | |
| 2057 // Check that peel_list entries are in the peel set | |
| 2058 for (i = 0; i < peel_list.size(); i++) { | |
| 2059 if (!peel.test(peel_list.at(i)->_idx)) { | |
| 2060 return false; | |
| 2061 } | |
| 2062 } | |
| 2063 // Check at loop members are in one of peel set or not_peel set | |
| 2064 for (i = 0; i < loop->_body.size(); i++ ) { | |
| 2065 Node *def = loop->_body.at(i); | |
| 2066 uint di = def->_idx; | |
| 2067 // Check that peel set elements are in peel_list | |
| 2068 if (peel.test(di)) { | |
| 2069 if (not_peel.test(di)) { | |
| 2070 return false; | |
| 2071 } | |
| 2072 // Must be in peel_list also | |
| 2073 bool found = false; | |
| 2074 for (uint j = 0; j < peel_list.size(); j++) { | |
| 2075 if (peel_list.at(j)->_idx == di) { | |
| 2076 found = true; | |
| 2077 break; | |
| 2078 } | |
| 2079 } | |
| 2080 if (!found) { | |
| 2081 return false; | |
| 2082 } | |
| 2083 } else if (not_peel.test(di)) { | |
| 2084 if (peel.test(di)) { | |
| 2085 return false; | |
| 2086 } | |
| 2087 } else { | |
| 2088 return false; | |
| 2089 } | |
| 2090 } | |
| 2091 return true; | |
| 2092 } | |
| 2093 | |
| 2094 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- | |
| 2095 // Ensure a use outside of loop is of the right form | |
| 2096 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { | |
| 2097 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
| 2098 return (use->is_Phi() && | |
| 2099 use_c->is_Region() && use_c->req() == 3 && | |
| 2100 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || | |
| 2101 use_c->in(exit_idx)->Opcode() == Op_IfFalse || | |
| 2102 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && | |
| 2103 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); | |
| 2104 } | |
| 2105 | |
| 2106 //------------------------------ is_valid_clone_loop_form ------------------------------------- | |
| 2107 // Ensure that all uses outside of loop are of the right form | |
| 2108 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, | |
| 2109 uint orig_exit_idx, uint clone_exit_idx) { | |
| 2110 uint len = peel_list.size(); | |
| 2111 for (uint i = 0; i < len; i++) { | |
| 2112 Node *def = peel_list.at(i); | |
| 2113 | |
| 2114 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
| 2115 Node *use = def->fast_out(j); | |
| 2116 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
| 2117 if (!loop->is_member(get_loop(use_c))) { | |
| 2118 // use is not in the loop, check for correct structure | |
| 2119 if (use->in(0) == def) { | |
| 2120 // Okay | |
| 2121 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { | |
| 2122 return false; | |
| 2123 } | |
| 2124 } | |
| 2125 } | |
| 2126 } | |
| 2127 return true; | |
| 2128 } | |
| 2129 #endif | |
| 2130 | |
| 2131 //------------------------------ partial_peel ------------------------------------- | |
| 2132 // Partially peel (aka loop rotation) the top portion of a loop (called | |
| 2133 // the peel section below) by cloning it and placing one copy just before | |
| 2134 // the new loop head and the other copy at the bottom of the new loop. | |
| 2135 // | |
| 2136 // before after where it came from | |
| 2137 // | |
| 2138 // stmt1 stmt1 | |
| 2139 // loop: stmt2 clone | |
| 2140 // stmt2 if condA goto exitA clone | |
| 2141 // if condA goto exitA new_loop: new | |
| 2142 // stmt3 stmt3 clone | |
| 2143 // if !condB goto loop if condB goto exitB clone | |
| 2144 // exitB: stmt2 orig | |
| 2145 // stmt4 if !condA goto new_loop orig | |
| 2146 // exitA: goto exitA | |
| 2147 // exitB: | |
| 2148 // stmt4 | |
| 2149 // exitA: | |
| 2150 // | |
| 2151 // Step 1: find the cut point: an exit test on probable | |
| 2152 // induction variable. | |
| 2153 // Step 2: schedule (with cloning) operations in the peel | |
| 2154 // section that can be executed after the cut into | |
| 2155 // the section that is not peeled. This may need | |
| 2156 // to clone operations into exit blocks. For | |
| 2157 // instance, a reference to A[i] in the not-peel | |
| 2158 // section and a reference to B[i] in an exit block | |
| 2159 // may cause a left-shift of i by 2 to be placed | |
| 2160 // in the peel block. This step will clone the left | |
| 2161 // shift into the exit block and sink the left shift | |
| 2162 // from the peel to the not-peel section. | |
| 2163 // Step 3: clone the loop, retarget the control, and insert | |
| 2164 // phis for values that are live across the new loop | |
| 2165 // head. This is very dependent on the graph structure | |
| 2166 // from clone_loop. It creates region nodes for | |
| 2167 // exit control and associated phi nodes for values | |
| 2168 // flow out of the loop through that exit. The region | |
| 2169 // node is dominated by the clone's control projection. | |
| 2170 // So the clone's peel section is placed before the | |
| 2171 // new loop head, and the clone's not-peel section is | |
| 2172 // forms the top part of the new loop. The original | |
| 2173 // peel section forms the tail of the new loop. | |
| 2174 // Step 4: update the dominator tree and recompute the | |
| 2175 // dominator depth. | |
| 2176 // | |
| 2177 // orig | |
| 2178 // | |
| 2179 // stmt1 | |
| 2180 // | | |
| 2181 // v | |
| 2182 // loop predicate | |
| 2183 // | | |
| 2184 // v | |
| 2185 // loop<----+ | |
| 2186 // | | | |
| 2187 // stmt2 | | |
| 2188 // | | | |
| 2189 // v | | |
| 2190 // ifA | | |
| 2191 // / | | | |
| 2192 // v v | | |
| 2193 // false true ^ <-- last_peel | |
| 2194 // / | | | |
| 2195 // / ===|==cut | | |
| 2196 // / stmt3 | <-- first_not_peel | |
| 2197 // / | | | |
| 2198 // | v | | |
| 2199 // v ifB | | |
| 2200 // exitA: / \ | | |
| 2201 // / \ | | |
| 2202 // v v | | |
| 2203 // false true | | |
| 2204 // / \ | | |
| 2205 // / ----+ | |
| 2206 // | | |
| 2207 // v | |
| 2208 // exitB: | |
| 2209 // stmt4 | |
| 2210 // | |
| 2211 // | |
| 2212 // after clone loop | |
| 2213 // | |
| 2214 // stmt1 | |
| 2215 // | | |
| 2216 // v | |
| 2217 // loop predicate | |
| 2218 // / \ | |
| 2219 // clone / \ orig | |
| 2220 // / \ | |
| 2221 // / \ | |
| 2222 // v v | |
| 2223 // +---->loop loop<----+ | |
| 2224 // | | | | | |
| 2225 // | stmt2 stmt2 | | |
| 2226 // | | | | | |
| 2227 // | v v | | |
| 2228 // | ifA ifA | | |
| 2229 // | | \ / | | | |
| 2230 // | v v v v | | |
| 2231 // ^ true false false true ^ <-- last_peel | |
| 2232 // | | ^ \ / | | | |
| 2233 // | cut==|== \ \ / ===|==cut | | |
| 2234 // | stmt3 \ \ / stmt3 | <-- first_not_peel | |
| 2235 // | | dom | | | | | |
| 2236 // | v \ 1v v2 v | | |
| 2237 // | ifB regionA ifB | | |
| 2238 // | / \ | / \ | | |
| 2239 // | / \ v / \ | | |
| 2240 // | v v exitA: v v | | |
| 2241 // | true false false true | | |
| 2242 // | / ^ \ / \ | | |
| 2243 // +---- \ \ / ----+ | |
| 2244 // dom \ / | |
| 2245 // \ 1v v2 | |
| 2246 // regionB | |
| 2247 // | | |
| 2248 // v | |
| 2249 // exitB: | |
| 2250 // stmt4 | |
| 2251 // | |
| 2252 // | |
| 2253 // after partial peel | |
| 2254 // | |
| 2255 // stmt1 | |
| 2256 // | | |
| 2257 // v | |
| 2258 // loop predicate | |
| 2259 // / | |
| 2260 // clone / orig | |
| 2261 // / TOP | |
| 2262 // / \ | |
| 2263 // v v | |
| 2264 // TOP->loop loop----+ | |
| 2265 // | | | | |
| 2266 // stmt2 stmt2 | | |
| 2267 // | | | | |
| 2268 // v v | | |
| 2269 // ifA ifA | | |
| 2270 // | \ / | | | |
| 2271 // v v v v | | |
| 2272 // true false false true | <-- last_peel | |
| 2273 // | ^ \ / +------|---+ | |
| 2274 // +->newloop \ \ / === ==cut | | | |
| 2275 // | stmt3 \ \ / TOP | | | |
| 2276 // | | dom | | stmt3 | | <-- first_not_peel | |
| 2277 // | v \ 1v v2 v | | | |
| 2278 // | ifB regionA ifB ^ v | |
| 2279 // | / \ | / \ | | | |
| 2280 // | / \ v / \ | | | |
| 2281 // | v v exitA: v v | | | |
| 2282 // | true false false true | | | |
| 2283 // | / ^ \ / \ | | | |
| 2284 // | | \ \ / v | | | |
| 2285 // | | dom \ / TOP | | | |
| 2286 // | | \ 1v v2 | | | |
| 2287 // ^ v regionB | | | |
| 2288 // | | | | | | |
| 2289 // | | v ^ v | |
| 2290 // | | exitB: | | | |
| 2291 // | | stmt4 | | | |
| 2292 // | +------------>-----------------+ | | |
| 2293 // | | | |
| 2294 // +-----------------<---------------------+ | |
| 2295 // | |
| 2296 // | |
| 2297 // final graph | |
| 2298 // | |
| 2299 // stmt1 | |
| 2300 // | | |
| 2301 // v | |
| 2302 // loop predicate | |
| 2303 // | | |
| 2304 // v | |
| 2305 // stmt2 clone | |
| 2306 // | | |
| 2307 // v | |
| 2308 // ........> ifA clone | |
| 2309 // : / | | |
| 2310 // dom / | | |
| 2311 // : v v | |
| 2312 // : false true | |
| 2313 // : | | | |
| 2314 // : | v | |
| 2315 // : | newloop<-----+ | |
| 2316 // : | | | | |
| 2317 // : | stmt3 clone | | |
| 2318 // : | | | | |
| 2319 // : | v | | |
| 2320 // : | ifB | | |
| 2321 // : | / \ | | |
| 2322 // : | v v | | |
| 2323 // : | false true | | |
| 2324 // : | | | | | |
| 2325 // : | v stmt2 | | |
| 2326 // : | exitB: | | | |
| 2327 // : | stmt4 v | | |
| 2328 // : | ifA orig | | |
| 2329 // : | / \ | | |
| 2330 // : | / \ | | |
| 2331 // : | v v | | |
| 2332 // : | false true | | |
| 2333 // : | / \ | | |
| 2334 // : v v -----+ | |
| 2335 // RegionA | |
| 2336 // | | |
| 2337 // v | |
| 2338 // exitA | |
| 2339 // | |
| 2340 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { | |
| 2341 | |
| 2342 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only"); | |
| 2343 if (!loop->_head->is_Loop()) { | |
| 2344 return false; } | |
| 2345 | |
| 2346 LoopNode *head = loop->_head->as_Loop(); | |
| 2347 | |
| 2348 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { | |
| 2349 return false; | |
| 2350 } | |
| 2351 | |
| 2352 // Check for complex exit control | |
| 2353 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { | |
| 2354 Node *n = loop->_body.at(ii); | |
| 2355 int opc = n->Opcode(); | |
| 2356 if (n->is_Call() || | |
| 2357 opc == Op_Catch || | |
| 2358 opc == Op_CatchProj || | |
| 2359 opc == Op_Jump || | |
| 2360 opc == Op_JumpProj) { | |
| 2361 #if !defined(PRODUCT) | |
| 2362 if (TracePartialPeeling) { | |
| 2363 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); | |
| 2364 } | |
| 2365 #endif | |
| 2366 return false; | |
| 2367 } | |
| 2368 } | |
| 2369 | |
| 2370 int dd = dom_depth(head); | |
| 2371 | |
| 2372 // Step 1: find cut point | |
| 2373 | |
| 2374 // Walk up dominators to loop head looking for first loop exit | |
| 2375 // which is executed on every path thru loop. | |
| 2376 IfNode *peel_if = NULL; | |
| 2377 IfNode *peel_if_cmpu = NULL; | |
| 2378 | |
| 2379 Node *iff = loop->tail(); | |
| 2380 while( iff != head ) { | |
| 2381 if( iff->is_If() ) { | |
| 2382 Node *ctrl = get_ctrl(iff->in(1)); | |
| 2383 if (ctrl->is_top()) return false; // Dead test on live IF. | |
| 2384 // If loop-varying exit-test, check for induction variable | |
| 2385 if( loop->is_member(get_loop(ctrl)) && | |
| 2386 loop->is_loop_exit(iff) && | |
| 2387 is_possible_iv_test(iff)) { | |
| 2388 Node* cmp = iff->in(1)->in(1); | |
| 2389 if (cmp->Opcode() == Op_CmpI) { | |
| 2390 peel_if = iff->as_If(); | |
| 2391 } else { | |
| 2392 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); | |
| 2393 peel_if_cmpu = iff->as_If(); | |
| 2394 } | |
| 2395 } | |
| 2396 } | |
| 2397 iff = idom(iff); | |
| 2398 } | |
| 2399 // Prefer signed compare over unsigned compare. | |
| 2400 IfNode* new_peel_if = NULL; | |
| 2401 if (peel_if == NULL) { | |
| 2402 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { | |
| 2403 return false; // No peel point found | |
| 2404 } | |
| 2405 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); | |
| 2406 if (new_peel_if == NULL) { | |
| 2407 return false; // No peel point found | |
| 2408 } | |
| 2409 peel_if = new_peel_if; | |
| 2410 } | |
| 2411 Node* last_peel = stay_in_loop(peel_if, loop); | |
| 2412 Node* first_not_peeled = stay_in_loop(last_peel, loop); | |
| 2413 if (first_not_peeled == NULL || first_not_peeled == head) { | |
| 2414 return false; | |
| 2415 } | |
| 2416 | |
| 2417 #if !defined(PRODUCT) | |
| 2418 if (TraceLoopOpts) { | |
| 2419 tty->print("PartialPeel "); | |
| 2420 loop->dump_head(); | |
| 2421 } | |
| 2422 | |
| 2423 if (TracePartialPeeling) { | |
| 2424 tty->print_cr("before partial peel one iteration"); | |
| 2425 Node_List wl; | |
| 2426 Node* t = head->in(2); | |
| 2427 while (true) { | |
| 2428 wl.push(t); | |
| 2429 if (t == head) break; | |
| 2430 t = idom(t); | |
| 2431 } | |
| 2432 while (wl.size() > 0) { | |
| 2433 Node* tt = wl.pop(); | |
| 2434 tt->dump(); | |
| 2435 if (tt == last_peel) tty->print_cr("-- cut --"); | |
| 2436 } | |
| 2437 } | |
| 2438 #endif | |
| 2439 ResourceArea *area = Thread::current()->resource_area(); | |
| 2440 VectorSet peel(area); | |
| 2441 VectorSet not_peel(area); | |
| 2442 Node_List peel_list(area); | |
| 2443 Node_List worklist(area); | |
| 2444 Node_List sink_list(area); | |
| 2445 | |
| 2446 // Set of cfg nodes to peel are those that are executable from | |
| 2447 // the head through last_peel. | |
| 2448 assert(worklist.size() == 0, "should be empty"); | |
| 2449 worklist.push(head); | |
| 2450 peel.set(head->_idx); | |
| 2451 while (worklist.size() > 0) { | |
| 2452 Node *n = worklist.pop(); | |
| 2453 if (n != last_peel) { | |
| 2454 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 2455 Node* use = n->fast_out(j); | |
| 2456 if (use->is_CFG() && | |
| 2457 loop->is_member(get_loop(use)) && | |
| 2458 !peel.test_set(use->_idx)) { | |
| 2459 worklist.push(use); | |
| 2460 } | |
| 2461 } | |
| 2462 } | |
| 2463 } | |
| 2464 | |
| 2465 // Set of non-cfg nodes to peel are those that are control | |
| 2466 // dependent on the cfg nodes. | |
| 2467 uint i; | |
| 2468 for(i = 0; i < loop->_body.size(); i++ ) { | |
| 2469 Node *n = loop->_body.at(i); | |
| 2470 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; | |
| 2471 if (peel.test(n_c->_idx)) { | |
| 2472 peel.set(n->_idx); | |
| 2473 } else { | |
| 2474 not_peel.set(n->_idx); | |
| 2475 } | |
| 2476 } | |
| 2477 | |
| 2478 // Step 2: move operations from the peeled section down into the | |
| 2479 // not-peeled section | |
| 2480 | |
| 2481 // Get a post order schedule of nodes in the peel region | |
| 2482 // Result in right-most operand. | |
| 2483 scheduled_nodelist(loop, peel, peel_list ); | |
| 2484 | |
| 2485 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
| 2486 | |
| 2487 // For future check for too many new phis | |
| 2488 uint old_phi_cnt = 0; | |
| 2489 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { | |
| 2490 Node* use = head->fast_out(j); | |
| 2491 if (use->is_Phi()) old_phi_cnt++; | |
| 2492 } | |
| 2493 | |
| 2494 #if !defined(PRODUCT) | |
| 2495 if (TracePartialPeeling) { | |
| 2496 tty->print_cr("\npeeled list"); | |
| 2497 } | |
| 2498 #endif | |
| 2499 | |
| 2500 // Evacuate nodes in peel region into the not_peeled region if possible | |
| 2501 uint new_phi_cnt = 0; | |
| 2502 uint cloned_for_outside_use = 0; | |
| 2503 for (i = 0; i < peel_list.size();) { | |
| 2504 Node* n = peel_list.at(i); | |
| 2505 #if !defined(PRODUCT) | |
| 2506 if (TracePartialPeeling) n->dump(); | |
| 2507 #endif | |
| 2508 bool incr = true; | |
| 2509 if ( !n->is_CFG() ) { | |
| 2510 | |
| 2511 if ( has_use_in_set(n, not_peel) ) { | |
| 2512 | |
| 2513 // If not used internal to the peeled region, | |
| 2514 // move "n" from peeled to not_peeled region. | |
| 2515 | |
| 2516 if ( !has_use_internal_to_set(n, peel, loop) ) { | |
| 2517 | |
| 2518 // if not pinned and not a load (which maybe anti-dependent on a store) | |
| 2519 // and not a CMove (Matcher expects only bool->cmove). | |
| 2520 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { | |
| 2521 cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist ); | |
| 2522 sink_list.push(n); | |
| 2523 peel >>= n->_idx; // delete n from peel set. | |
| 2524 not_peel <<= n->_idx; // add n to not_peel set. | |
| 2525 peel_list.remove(i); | |
| 2526 incr = false; | |
| 2527 #if !defined(PRODUCT) | |
| 2528 if (TracePartialPeeling) { | |
| 2529 tty->print_cr("sink to not_peeled region: %d newbb: %d", | |
| 2530 n->_idx, get_ctrl(n)->_idx); | |
| 2531 } | |
| 2532 #endif | |
| 2533 } | |
| 2534 } else { | |
| 2535 // Otherwise check for special def-use cases that span | |
| 2536 // the peel/not_peel boundary such as bool->if | |
| 2537 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); | |
| 2538 new_phi_cnt++; | |
| 2539 } | |
| 2540 } | |
| 2541 } | |
| 2542 if (incr) i++; | |
| 2543 } | |
| 2544 | |
| 2545 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { | |
| 2546 #if !defined(PRODUCT) | |
| 2547 if (TracePartialPeeling) { | |
| 2548 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", | |
| 2549 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); | |
| 2550 } | |
| 2551 #endif | |
| 2552 if (new_peel_if != NULL) { | |
| 2553 remove_cmpi_loop_exit(new_peel_if, loop); | |
| 2554 } | |
| 2555 // Inhibit more partial peeling on this loop | |
| 2556 assert(!head->is_partial_peel_loop(), "not partial peeled"); | |
| 2557 head->mark_partial_peel_failed(); | |
| 2558 if (cloned_for_outside_use > 0) { | |
| 2559 // Terminate this round of loop opts because | |
| 2560 // the graph outside this loop was changed. | |
| 2561 C->set_major_progress(); | |
| 2562 return true; | |
| 2563 } | |
| 2564 return false; | |
| 2565 } | |
| 2566 | |
| 2567 // Step 3: clone loop, retarget control, and insert new phis | |
| 2568 | |
| 2569 // Create new loop head for new phis and to hang | |
| 2570 // the nodes being moved (sinked) from the peel region. | |
| 2571 LoopNode* new_head = new (C) LoopNode(last_peel, last_peel); | |
| 2572 new_head->set_unswitch_count(head->unswitch_count()); // Preserve | |
| 2573 _igvn.register_new_node_with_optimizer(new_head); | |
| 2574 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); | |
| 2575 first_not_peeled->set_req(0, new_head); | |
| 2576 set_loop(new_head, loop); | |
| 2577 loop->_body.push(new_head); | |
| 2578 not_peel.set(new_head->_idx); | |
| 2579 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); | |
| 2580 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); | |
| 2581 | |
| 2582 while (sink_list.size() > 0) { | |
| 2583 Node* n = sink_list.pop(); | |
| 2584 set_ctrl(n, new_head); | |
| 2585 } | |
| 2586 | |
| 2587 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
| 2588 | |
| 2589 clone_loop( loop, old_new, dd ); | |
| 2590 | |
| 2591 const uint clone_exit_idx = 1; | |
| 2592 const uint orig_exit_idx = 2; | |
| 2593 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); | |
| 2594 | |
| 2595 Node* head_clone = old_new[head->_idx]; | |
| 2596 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); | |
| 2597 Node* orig_tail_clone = head_clone->in(2); | |
| 2598 | |
| 2599 // Add phi if "def" node is in peel set and "use" is not | |
| 2600 | |
| 2601 for(i = 0; i < peel_list.size(); i++ ) { | |
| 2602 Node *def = peel_list.at(i); | |
| 2603 if (!def->is_CFG()) { | |
| 2604 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
| 2605 Node *use = def->fast_out(j); | |
| 2606 if (has_node(use) && use->in(0) != C->top() && | |
| 2607 (!peel.test(use->_idx) || | |
| 2608 (use->is_Phi() && use->in(0) == head)) ) { | |
| 2609 worklist.push(use); | |
| 2610 } | |
| 2611 } | |
| 2612 while( worklist.size() ) { | |
| 2613 Node *use = worklist.pop(); | |
| 2614 for (uint j = 1; j < use->req(); j++) { | |
| 2615 Node* n = use->in(j); | |
| 2616 if (n == def) { | |
| 2617 | |
| 2618 // "def" is in peel set, "use" is not in peel set | |
| 2619 // or "use" is in the entry boundary (a phi) of the peel set | |
| 2620 | |
| 2621 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
| 2622 | |
| 2623 if ( loop->is_member(get_loop( use_c )) ) { | |
| 2624 // use is in loop | |
| 2625 if (old_new[use->_idx] != NULL) { // null for dead code | |
| 2626 Node* use_clone = old_new[use->_idx]; | |
| 2627 _igvn.replace_input_of(use, j, C->top()); | |
| 2628 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); | |
| 2629 } | |
| 2630 } else { | |
| 2631 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); | |
| 2632 // use is not in the loop, check if the live range includes the cut | |
| 2633 Node* lp_if = use_c->in(orig_exit_idx)->in(0); | |
| 2634 if (not_peel.test(lp_if->_idx)) { | |
| 2635 assert(j == orig_exit_idx, "use from original loop"); | |
| 2636 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); | |
| 2637 } | |
| 2638 } | |
| 2639 } | |
| 2640 } | |
| 2641 } | |
| 2642 } | |
| 2643 } | |
| 2644 | |
| 2645 // Step 3b: retarget control | |
| 2646 | |
| 2647 // Redirect control to the new loop head if a cloned node in | |
| 2648 // the not_peeled region has control that points into the peeled region. | |
| 2649 // This necessary because the cloned peeled region will be outside | |
| 2650 // the loop. | |
| 2651 // from to | |
| 2652 // cloned-peeled <---+ | |
| 2653 // new_head_clone: | <--+ | |
| 2654 // cloned-not_peeled in(0) in(0) | |
| 2655 // orig-peeled | |
| 2656 | |
| 2657 for(i = 0; i < loop->_body.size(); i++ ) { | |
| 2658 Node *n = loop->_body.at(i); | |
| 2659 if (!n->is_CFG() && n->in(0) != NULL && | |
| 2660 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { | |
| 2661 Node* n_clone = old_new[n->_idx]; | |
| 2662 _igvn.replace_input_of(n_clone, 0, new_head_clone); | |
| 2663 } | |
| 2664 } | |
| 2665 | |
| 2666 // Backedge of the surviving new_head (the clone) is original last_peel | |
| 2667 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel); | |
| 2668 | |
| 2669 // Cut first node in original not_peel set | |
| 2670 _igvn.rehash_node_delayed(new_head); // Multiple edge updates: | |
| 2671 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of | |
| 2672 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls | |
| 2673 | |
| 2674 // Copy head_clone back-branch info to original head | |
| 2675 // and remove original head's loop entry and | |
| 2676 // clone head's back-branch | |
| 2677 _igvn.rehash_node_delayed(head); // Multiple edge updates | |
| 2678 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); | |
| 2679 head->set_req(LoopNode::LoopBackControl, C->top()); | |
| 2680 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top()); | |
| 2681 | |
| 2682 // Similarly modify the phis | |
| 2683 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { | |
| 2684 Node* use = head->fast_out(k); | |
| 2685 if (use->is_Phi() && use->outcnt() > 0) { | |
| 2686 Node* use_clone = old_new[use->_idx]; | |
| 2687 _igvn.rehash_node_delayed(use); // Multiple edge updates | |
| 2688 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); | |
| 2689 use->set_req(LoopNode::LoopBackControl, C->top()); | |
| 2690 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top()); | |
| 2691 } | |
| 2692 } | |
| 2693 | |
| 2694 // Step 4: update dominator tree and dominator depth | |
| 2695 | |
| 2696 set_idom(head, orig_tail_clone, dd); | |
| 2697 recompute_dom_depth(); | |
| 2698 | |
| 2699 // Inhibit more partial peeling on this loop | |
| 2700 new_head_clone->set_partial_peel_loop(); | |
| 2701 C->set_major_progress(); | |
| 2702 loop->record_for_igvn(); | |
| 2703 | |
| 2704 #if !defined(PRODUCT) | |
| 2705 if (TracePartialPeeling) { | |
| 2706 tty->print_cr("\nafter partial peel one iteration"); | |
| 2707 Node_List wl(area); | |
| 2708 Node* t = last_peel; | |
| 2709 while (true) { | |
| 2710 wl.push(t); | |
| 2711 if (t == head_clone) break; | |
| 2712 t = idom(t); | |
| 2713 } | |
| 2714 while (wl.size() > 0) { | |
| 2715 Node* tt = wl.pop(); | |
| 2716 if (tt == head) tty->print_cr("orig head"); | |
| 2717 else if (tt == new_head_clone) tty->print_cr("new head"); | |
| 2718 else if (tt == head_clone) tty->print_cr("clone head"); | |
| 2719 tt->dump(); | |
| 2720 } | |
| 2721 } | |
| 2722 #endif | |
| 2723 return true; | |
| 2724 } | |
| 2725 | |
| 2726 //------------------------------reorg_offsets---------------------------------- | |
| 2727 // Reorganize offset computations to lower register pressure. Mostly | |
| 2728 // prevent loop-fallout uses of the pre-incremented trip counter (which are | |
| 2729 // then alive with the post-incremented trip counter forcing an extra | |
| 2730 // register move) | |
| 2731 void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) { | |
| 2732 // Perform it only for canonical counted loops. | |
| 2733 // Loop's shape could be messed up by iteration_split_impl. | |
| 2734 if (!loop->_head->is_CountedLoop()) | |
| 2735 return; | |
| 2736 if (!loop->_head->as_Loop()->is_valid_counted_loop()) | |
| 2737 return; | |
| 2738 | |
| 2739 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
| 2740 CountedLoopEndNode *cle = cl->loopexit(); | |
| 2741 Node *exit = cle->proj_out(false); | |
| 2742 Node *phi = cl->phi(); | |
| 2743 | |
| 2744 // Check for the special case of folks using the pre-incremented | |
| 2745 // trip-counter on the fall-out path (forces the pre-incremented | |
| 2746 // and post-incremented trip counter to be live at the same time). | |
| 2747 // Fix this by adjusting to use the post-increment trip counter. | |
| 2748 | |
| 2749 bool progress = true; | |
| 2750 while (progress) { | |
| 2751 progress = false; | |
| 2752 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { | |
| 2753 Node* use = phi->fast_out(i); // User of trip-counter | |
| 2754 if (!has_ctrl(use)) continue; | |
| 2755 Node *u_ctrl = get_ctrl(use); | |
| 2756 if (use->is_Phi()) { | |
| 2757 u_ctrl = NULL; | |
| 2758 for (uint j = 1; j < use->req(); j++) | |
| 2759 if (use->in(j) == phi) | |
| 2760 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j)); | |
| 2761 } | |
| 2762 IdealLoopTree *u_loop = get_loop(u_ctrl); | |
| 2763 // Look for loop-invariant use | |
| 2764 if (u_loop == loop) continue; | |
| 2765 if (loop->is_member(u_loop)) continue; | |
| 2766 // Check that use is live out the bottom. Assuming the trip-counter | |
| 2767 // update is right at the bottom, uses of of the loop middle are ok. | |
| 2768 if (dom_lca(exit, u_ctrl) != exit) continue; | |
| 2769 // Hit! Refactor use to use the post-incremented tripcounter. | |
| 2770 // Compute a post-increment tripcounter. | |
| 2771 Node *opaq = new (C) Opaque2Node( C, cle->incr() ); | |
| 2772 register_new_node(opaq, exit); | |
| 2773 Node *neg_stride = _igvn.intcon(-cle->stride_con()); | |
| 2774 set_ctrl(neg_stride, C->root()); | |
| 2775 Node *post = new (C) AddINode( opaq, neg_stride); | |
| 2776 register_new_node(post, exit); | |
| 2777 _igvn.rehash_node_delayed(use); | |
| 2778 for (uint j = 1; j < use->req(); j++) { | |
| 2779 if (use->in(j) == phi) | |
| 2780 use->set_req(j, post); | |
| 2781 } | |
| 2782 // Since DU info changed, rerun loop | |
| 2783 progress = true; | |
| 2784 break; | |
| 2785 } | |
| 2786 } | |
| 2787 | |
| 2788 } |
