Mercurial > hg > truffle
annotate src/share/vm/opto/loopopts.cpp @ 70:b683f557224b
6661247: Internal bug in 32-bit HotSpot optimizer while bit manipulations
Summary: copy elimination of a constant value results in incorrect execution
Reviewed-by: kvn, sgoldman, rasbold
| author | never |
|---|---|
| date | Wed, 19 Mar 2008 15:14:36 -0700 |
| parents | 8bb88f9877e5 |
| children | a761c2d3b76a |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Copyright 1999-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_loopopts.cpp.incl" | |
| 27 | |
| 28 //============================================================================= | |
| 29 //------------------------------split_thru_phi--------------------------------- | |
| 30 // Split Node 'n' through merge point if there is enough win. | |
| 31 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { | |
| 69 | 32 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { |
| 33 // ConvI2L may have type information on it which is unsafe to push up | |
| 34 // so disable this for now | |
| 35 return NULL; | |
| 36 } | |
| 0 | 37 int wins = 0; |
| 38 assert( !n->is_CFG(), "" ); | |
| 39 assert( region->is_Region(), "" ); | |
|
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40 |
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41 const Type* type = n->bottom_type(); |
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42 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); |
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43 Node *phi; |
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44 if( t_oop != NULL && t_oop->is_instance_field() ) { |
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45 int iid = t_oop->instance_id(); |
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46 int index = C->get_alias_index(t_oop); |
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47 int offset = t_oop->offset(); |
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48 phi = new (C,region->req()) PhiNode(region, type, NULL, iid, index, offset); |
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49 } else { |
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50 phi = new (C,region->req()) PhiNode(region, type); |
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51 } |
| 0 | 52 uint old_unique = C->unique(); |
| 53 for( uint i = 1; i < region->req(); i++ ) { | |
| 54 Node *x; | |
| 55 Node* the_clone = NULL; | |
| 56 if( region->in(i) == C->top() ) { | |
| 57 x = C->top(); // Dead path? Use a dead data op | |
| 58 } else { | |
| 59 x = n->clone(); // Else clone up the data op | |
| 60 the_clone = x; // Remember for possible deletion. | |
| 61 // Alter data node to use pre-phi inputs | |
| 62 if( n->in(0) == region ) | |
| 63 x->set_req( 0, region->in(i) ); | |
| 64 for( uint j = 1; j < n->req(); j++ ) { | |
| 65 Node *in = n->in(j); | |
| 66 if( in->is_Phi() && in->in(0) == region ) | |
| 67 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone | |
| 68 } | |
| 69 } | |
| 70 // Check for a 'win' on some paths | |
| 71 const Type *t = x->Value(&_igvn); | |
| 72 | |
| 73 bool singleton = t->singleton(); | |
| 74 | |
| 75 // A TOP singleton indicates that there are no possible values incoming | |
| 76 // along a particular edge. In most cases, this is OK, and the Phi will | |
| 77 // be eliminated later in an Ideal call. However, we can't allow this to | |
| 78 // happen if the singleton occurs on loop entry, as the elimination of | |
| 79 // the PhiNode may cause the resulting node to migrate back to a previous | |
| 80 // loop iteration. | |
| 81 if( singleton && t == Type::TOP ) { | |
| 82 // Is_Loop() == false does not confirm the absence of a loop (e.g., an | |
| 83 // irreducible loop may not be indicated by an affirmative is_Loop()); | |
| 84 // therefore, the only top we can split thru a phi is on a backedge of | |
| 85 // a loop. | |
| 86 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); | |
| 87 } | |
| 88 | |
| 89 if( singleton ) { | |
| 90 wins++; | |
| 91 x = ((PhaseGVN&)_igvn).makecon(t); | |
| 92 } else { | |
| 93 // We now call Identity to try to simplify the cloned node. | |
| 94 // Note that some Identity methods call phase->type(this). | |
| 95 // Make sure that the type array is big enough for | |
| 96 // our new node, even though we may throw the node away. | |
| 97 // (Note: This tweaking with igvn only works because x is a new node.) | |
| 98 _igvn.set_type(x, t); | |
| 99 Node *y = x->Identity(&_igvn); | |
| 100 if( y != x ) { | |
| 101 wins++; | |
| 102 x = y; | |
| 103 } else { | |
| 104 y = _igvn.hash_find(x); | |
| 105 if( y ) { | |
| 106 wins++; | |
| 107 x = y; | |
| 108 } else { | |
| 109 // Else x is a new node we are keeping | |
| 110 // We do not need register_new_node_with_optimizer | |
| 111 // because set_type has already been called. | |
| 112 _igvn._worklist.push(x); | |
| 113 } | |
| 114 } | |
| 115 } | |
| 116 if (x != the_clone && the_clone != NULL) | |
| 117 _igvn.remove_dead_node(the_clone); | |
| 118 phi->set_req( i, x ); | |
| 119 } | |
| 120 // Too few wins? | |
| 121 if( wins <= policy ) { | |
| 122 _igvn.remove_dead_node(phi); | |
| 123 return NULL; | |
| 124 } | |
| 125 | |
| 126 // Record Phi | |
| 127 register_new_node( phi, region ); | |
| 128 | |
| 129 for( uint i2 = 1; i2 < phi->req(); i2++ ) { | |
| 130 Node *x = phi->in(i2); | |
| 131 // If we commoned up the cloned 'x' with another existing Node, | |
| 132 // the existing Node picks up a new use. We need to make the | |
| 133 // existing Node occur higher up so it dominates its uses. | |
| 134 Node *old_ctrl; | |
| 135 IdealLoopTree *old_loop; | |
| 136 | |
| 137 // The occasional new node | |
| 138 if( x->_idx >= old_unique ) { // Found a new, unplaced node? | |
| 139 old_ctrl = x->is_Con() ? C->root() : NULL; | |
| 140 old_loop = NULL; // Not in any prior loop | |
| 141 } else { | |
| 142 old_ctrl = x->is_Con() ? C->root() : get_ctrl(x); | |
| 143 old_loop = get_loop(old_ctrl); // Get prior loop | |
| 144 } | |
| 145 // New late point must dominate new use | |
| 146 Node *new_ctrl = dom_lca( old_ctrl, region->in(i2) ); | |
| 147 // Set new location | |
| 148 set_ctrl(x, new_ctrl); | |
| 149 IdealLoopTree *new_loop = get_loop( new_ctrl ); | |
| 150 // If changing loop bodies, see if we need to collect into new body | |
| 151 if( old_loop != new_loop ) { | |
| 152 if( old_loop && !old_loop->_child ) | |
| 153 old_loop->_body.yank(x); | |
| 154 if( !new_loop->_child ) | |
| 155 new_loop->_body.push(x); // Collect body info | |
| 156 } | |
| 157 } | |
| 158 | |
| 159 return phi; | |
| 160 } | |
| 161 | |
| 162 //------------------------------dominated_by------------------------------------ | |
| 163 // Replace the dominated test with an obvious true or false. Place it on the | |
| 164 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the | |
| 165 // live path up to the dominating control. | |
| 166 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff ) { | |
| 167 #ifndef PRODUCT | |
| 168 if( VerifyLoopOptimizations && PrintOpto ) tty->print_cr("dominating test"); | |
| 169 #endif | |
| 170 | |
| 171 | |
| 172 // prevdom is the dominating projection of the dominating test. | |
| 173 assert( iff->is_If(), "" ); | |
| 174 assert( iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
| 175 int pop = prevdom->Opcode(); | |
| 176 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); | |
| 177 // 'con' is set to true or false to kill the dominated test. | |
| 178 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); | |
| 179 set_ctrl(con, C->root()); // Constant gets a new use | |
| 180 // Hack the dominated test | |
| 181 _igvn.hash_delete(iff); | |
| 182 iff->set_req(1, con); | |
| 183 _igvn._worklist.push(iff); | |
| 184 | |
| 185 // If I dont have a reachable TRUE and FALSE path following the IfNode then | |
| 186 // I can assume this path reaches an infinite loop. In this case it's not | |
| 187 // important to optimize the data Nodes - either the whole compilation will | |
| 188 // be tossed or this path (and all data Nodes) will go dead. | |
| 189 if( iff->outcnt() != 2 ) return; | |
| 190 | |
| 191 // Make control-dependent data Nodes on the live path (path that will remain | |
| 192 // once the dominated IF is removed) become control-dependent on the | |
| 193 // dominating projection. | |
| 194 Node* dp = ((IfNode*)iff)->proj_out(pop == Op_IfTrue); | |
| 195 IdealLoopTree *old_loop = get_loop(dp); | |
| 196 | |
| 197 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
| 198 Node* cd = dp->fast_out(i); // Control-dependent node | |
| 199 if( cd->depends_only_on_test() ) { | |
| 200 assert( cd->in(0) == dp, "" ); | |
| 201 _igvn.hash_delete( cd ); | |
| 202 cd->set_req(0, prevdom); | |
| 203 set_early_ctrl( cd ); | |
| 204 _igvn._worklist.push(cd); | |
| 205 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); | |
| 206 if( old_loop != new_loop ) { | |
| 207 if( !old_loop->_child ) old_loop->_body.yank(cd); | |
| 208 if( !new_loop->_child ) new_loop->_body.push(cd); | |
| 209 } | |
| 210 --i; | |
| 211 --imax; | |
| 212 } | |
| 213 } | |
| 214 } | |
| 215 | |
| 216 //------------------------------has_local_phi_input---------------------------- | |
| 217 // Return TRUE if 'n' has Phi inputs from its local block and no other | |
| 218 // block-local inputs (all non-local-phi inputs come from earlier blocks) | |
| 219 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { | |
| 220 Node *n_ctrl = get_ctrl(n); | |
| 221 // See if some inputs come from a Phi in this block, or from before | |
| 222 // this block. | |
| 223 uint i; | |
| 224 for( i = 1; i < n->req(); i++ ) { | |
| 225 Node *phi = n->in(i); | |
| 226 if( phi->is_Phi() && phi->in(0) == n_ctrl ) | |
| 227 break; | |
| 228 } | |
| 229 if( i >= n->req() ) | |
| 230 return NULL; // No Phi inputs; nowhere to clone thru | |
| 231 | |
| 232 // Check for inputs created between 'n' and the Phi input. These | |
| 233 // must split as well; they have already been given the chance | |
| 234 // (courtesy of a post-order visit) and since they did not we must | |
| 235 // recover the 'cost' of splitting them by being very profitable | |
| 236 // when splitting 'n'. Since this is unlikely we simply give up. | |
| 237 for( i = 1; i < n->req(); i++ ) { | |
| 238 Node *m = n->in(i); | |
| 239 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { | |
| 240 // We allow the special case of AddP's with no local inputs. | |
| 241 // This allows us to split-up address expressions. | |
| 242 if (m->is_AddP() && | |
| 243 get_ctrl(m->in(2)) != n_ctrl && | |
| 244 get_ctrl(m->in(3)) != n_ctrl) { | |
| 245 // Move the AddP up to dominating point | |
| 246 set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); | |
| 247 continue; | |
| 248 } | |
| 249 return NULL; | |
| 250 } | |
| 251 } | |
| 252 | |
| 253 return n_ctrl; | |
| 254 } | |
| 255 | |
| 256 //------------------------------remix_address_expressions---------------------- | |
| 257 // Rework addressing expressions to get the most loop-invariant stuff | |
| 258 // moved out. We'd like to do all associative operators, but it's especially | |
| 259 // important (common) to do address expressions. | |
| 260 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { | |
| 261 if (!has_ctrl(n)) return NULL; | |
| 262 Node *n_ctrl = get_ctrl(n); | |
| 263 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
| 264 | |
| 265 // See if 'n' mixes loop-varying and loop-invariant inputs and | |
| 266 // itself is loop-varying. | |
| 267 | |
| 268 // Only interested in binary ops (and AddP) | |
| 269 if( n->req() < 3 || n->req() > 4 ) return NULL; | |
| 270 | |
| 271 Node *n1_ctrl = get_ctrl(n->in( 1)); | |
| 272 Node *n2_ctrl = get_ctrl(n->in( 2)); | |
| 273 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); | |
| 274 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); | |
| 275 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); | |
| 276 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); | |
| 277 | |
| 278 // Does one of my inputs spin in a tighter loop than self? | |
| 279 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || | |
| 280 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || | |
| 281 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) | |
| 282 return NULL; // Leave well enough alone | |
| 283 | |
| 284 // Is at least one of my inputs loop-invariant? | |
| 285 if( n1_loop == n_loop && | |
| 286 n2_loop == n_loop && | |
| 287 n3_loop == n_loop ) | |
| 288 return NULL; // No loop-invariant inputs | |
| 289 | |
| 290 | |
| 291 int n_op = n->Opcode(); | |
| 292 | |
| 293 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). | |
| 294 if( n_op == Op_LShiftI ) { | |
| 295 // Scale is loop invariant | |
| 296 Node *scale = n->in(2); | |
| 297 Node *scale_ctrl = get_ctrl(scale); | |
| 298 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); | |
| 299 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) | |
| 300 return NULL; | |
| 301 const TypeInt *scale_t = scale->bottom_type()->isa_int(); | |
| 302 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) | |
| 303 return NULL; // Dont bother with byte/short masking | |
| 304 // Add must vary with loop (else shift would be loop-invariant) | |
| 305 Node *add = n->in(1); | |
| 306 Node *add_ctrl = get_ctrl(add); | |
| 307 IdealLoopTree *add_loop = get_loop(add_ctrl); | |
| 308 //assert( n_loop == add_loop, "" ); | |
| 309 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops | |
| 310 | |
| 311 // Convert I-V into I+ (0-V); same for V-I | |
| 312 if( add->Opcode() == Op_SubI && | |
| 313 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { | |
| 314 Node *zero = _igvn.intcon(0); | |
| 315 set_ctrl(zero, C->root()); | |
| 316 Node *neg = new (C, 3) SubINode( _igvn.intcon(0), add->in(2) ); | |
| 317 register_new_node( neg, get_ctrl(add->in(2) ) ); | |
| 318 add = new (C, 3) AddINode( add->in(1), neg ); | |
| 319 register_new_node( add, add_ctrl ); | |
| 320 } | |
| 321 if( add->Opcode() != Op_AddI ) return NULL; | |
| 322 // See if one add input is loop invariant | |
| 323 Node *add_var = add->in(1); | |
| 324 Node *add_var_ctrl = get_ctrl(add_var); | |
| 325 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
| 326 Node *add_invar = add->in(2); | |
| 327 Node *add_invar_ctrl = get_ctrl(add_invar); | |
| 328 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); | |
| 329 if( add_var_loop == n_loop ) { | |
| 330 } else if( add_invar_loop == n_loop ) { | |
| 331 // Swap to find the invariant part | |
| 332 add_invar = add_var; | |
| 333 add_invar_ctrl = add_var_ctrl; | |
| 334 add_invar_loop = add_var_loop; | |
| 335 add_var = add->in(2); | |
| 336 Node *add_var_ctrl = get_ctrl(add_var); | |
| 337 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
| 338 } else // Else neither input is loop invariant | |
| 339 return NULL; | |
| 340 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) | |
| 341 return NULL; // No invariant part of the add? | |
| 342 | |
| 343 // Yes! Reshape address expression! | |
| 344 Node *inv_scale = new (C, 3) LShiftINode( add_invar, scale ); | |
| 345 register_new_node( inv_scale, add_invar_ctrl ); | |
| 346 Node *var_scale = new (C, 3) LShiftINode( add_var, scale ); | |
| 347 register_new_node( var_scale, n_ctrl ); | |
| 348 Node *var_add = new (C, 3) AddINode( var_scale, inv_scale ); | |
| 349 register_new_node( var_add, n_ctrl ); | |
| 350 _igvn.hash_delete( n ); | |
| 351 _igvn.subsume_node( n, var_add ); | |
| 352 return var_add; | |
| 353 } | |
| 354 | |
| 355 // Replace (I+V) with (V+I) | |
| 356 if( n_op == Op_AddI || | |
| 357 n_op == Op_AddL || | |
| 358 n_op == Op_AddF || | |
| 359 n_op == Op_AddD || | |
| 360 n_op == Op_MulI || | |
| 361 n_op == Op_MulL || | |
| 362 n_op == Op_MulF || | |
| 363 n_op == Op_MulD ) { | |
| 364 if( n2_loop == n_loop ) { | |
| 365 assert( n1_loop != n_loop, "" ); | |
| 366 n->swap_edges(1, 2); | |
| 367 } | |
| 368 } | |
| 369 | |
| 370 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), | |
| 371 // but not if I2 is a constant. | |
| 372 if( n_op == Op_AddP ) { | |
| 373 if( n2_loop == n_loop && n3_loop != n_loop ) { | |
| 374 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { | |
| 375 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); | |
| 376 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); | |
| 377 IdealLoopTree *n22loop = get_loop( n22_ctrl ); | |
| 378 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); | |
| 379 if( n22loop != n_loop && n22loop->is_member(n_loop) && | |
| 380 n23_loop == n_loop ) { | |
| 381 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); | |
| 382 // Stuff new AddP in the loop preheader | |
| 383 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
| 384 Node *add2 = new (C, 4) AddPNode( n->in(1), add1, n->in(2)->in(3) ); | |
| 385 register_new_node( add2, n_ctrl ); | |
| 386 _igvn.hash_delete( n ); | |
| 387 _igvn.subsume_node( n, add2 ); | |
| 388 return add2; | |
| 389 } | |
| 390 } | |
| 391 } | |
| 392 | |
| 393 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) | |
| 394 if( n2_loop != n_loop && n3_loop == n_loop ) { | |
| 395 if( n->in(3)->Opcode() == Op_AddI ) { | |
| 396 Node *V = n->in(3)->in(1); | |
| 397 Node *I = n->in(3)->in(2); | |
| 398 if( is_member(n_loop,get_ctrl(V)) ) { | |
| 399 } else { | |
| 400 Node *tmp = V; V = I; I = tmp; | |
| 401 } | |
| 402 if( !is_member(n_loop,get_ctrl(I)) ) { | |
| 403 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2), I ); | |
| 404 // Stuff new AddP in the loop preheader | |
| 405 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
| 406 Node *add2 = new (C, 4) AddPNode( n->in(1), add1, V ); | |
| 407 register_new_node( add2, n_ctrl ); | |
| 408 _igvn.hash_delete( n ); | |
| 409 _igvn.subsume_node( n, add2 ); | |
| 410 return add2; | |
| 411 } | |
| 412 } | |
| 413 } | |
| 414 } | |
| 415 | |
| 416 return NULL; | |
| 417 } | |
| 418 | |
| 419 //------------------------------conditional_move------------------------------- | |
| 420 // Attempt to replace a Phi with a conditional move. We have some pretty | |
| 421 // strict profitability requirements. All Phis at the merge point must | |
| 422 // be converted, so we can remove the control flow. We need to limit the | |
| 423 // number of c-moves to a small handful. All code that was in the side-arms | |
| 424 // of the CFG diamond is now speculatively executed. This code has to be | |
| 425 // "cheap enough". We are pretty much limited to CFG diamonds that merge | |
| 426 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. | |
| 427 Node *PhaseIdealLoop::conditional_move( Node *region ) { | |
| 428 | |
| 429 assert( region->is_Region(), "sanity check" ); | |
| 430 if( region->req() != 3 ) return NULL; | |
| 431 | |
| 432 // Check for CFG diamond | |
| 433 Node *lp = region->in(1); | |
| 434 Node *rp = region->in(2); | |
| 435 if( !lp || !rp ) return NULL; | |
| 436 Node *lp_c = lp->in(0); | |
| 437 if( lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If() ) return NULL; | |
| 438 IfNode *iff = lp_c->as_If(); | |
| 439 | |
| 440 // Check for highly predictable branch. No point in CMOV'ing if | |
| 441 // we are going to predict accurately all the time. | |
| 442 // %%% This hides patterns produced by utility methods like Math.min. | |
| 443 if( iff->_prob < PROB_UNLIKELY_MAG(3) || | |
| 444 iff->_prob > PROB_LIKELY_MAG(3) ) | |
| 445 return NULL; | |
| 446 | |
| 447 // Check for ops pinned in an arm of the diamond. | |
| 448 // Can't remove the control flow in this case | |
| 449 if( lp->outcnt() > 1 ) return NULL; | |
| 450 if( rp->outcnt() > 1 ) return NULL; | |
| 451 | |
| 452 // Check profitability | |
| 453 int cost = 0; | |
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454 int phis = 0; |
| 0 | 455 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
| 456 Node *out = region->fast_out(i); | |
| 457 if( !out->is_Phi() ) continue; // Ignore other control edges, etc | |
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458 phis++; |
| 0 | 459 PhiNode* phi = out->as_Phi(); |
| 460 switch (phi->type()->basic_type()) { | |
| 461 case T_LONG: | |
| 462 cost++; // Probably encodes as 2 CMOV's | |
| 463 case T_INT: // These all CMOV fine | |
| 464 case T_FLOAT: | |
| 465 case T_DOUBLE: | |
| 466 case T_ADDRESS: // (RawPtr) | |
| 467 cost++; | |
| 468 break; | |
| 469 case T_OBJECT: { // Base oops are OK, but not derived oops | |
| 470 const TypeOopPtr *tp = phi->type()->isa_oopptr(); | |
| 471 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a | |
| 472 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus | |
| 473 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we | |
| 474 // have a Phi for the base here that we convert to a CMOVE all is well | |
| 475 // and good. But if the base is dead, we'll not make a CMOVE. Later | |
| 476 // the allocator will have to produce a base by creating a CMOVE of the | |
| 477 // relevant bases. This puts the allocator in the business of | |
| 478 // manufacturing expensive instructions, generally a bad plan. | |
| 479 // Just Say No to Conditionally-Moved Derived Pointers. | |
| 480 if( tp && tp->offset() != 0 ) | |
| 481 return NULL; | |
| 482 cost++; | |
| 483 break; | |
| 484 } | |
| 485 default: | |
| 486 return NULL; // In particular, can't do memory or I/O | |
| 487 } | |
| 488 // Add in cost any speculative ops | |
| 489 for( uint j = 1; j < region->req(); j++ ) { | |
| 490 Node *proj = region->in(j); | |
| 491 Node *inp = phi->in(j); | |
| 492 if (get_ctrl(inp) == proj) { // Found local op | |
| 493 cost++; | |
| 494 // Check for a chain of dependent ops; these will all become | |
| 495 // speculative in a CMOV. | |
| 496 for( uint k = 1; k < inp->req(); k++ ) | |
| 497 if (get_ctrl(inp->in(k)) == proj) | |
| 498 return NULL; // Too much speculative goo | |
| 499 } | |
| 500 } | |
| 501 // See if the Phi is used by a Cmp. This will likely Split-If, a | |
| 502 // higher-payoff operation. | |
| 503 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { | |
| 504 Node* use = phi->fast_out(k); | |
| 505 if( use->is_Cmp() ) | |
| 506 return NULL; | |
| 507 } | |
| 508 } | |
| 509 if( cost >= ConditionalMoveLimit ) return NULL; // Too much goo | |
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510 Node* bol = iff->in(1); |
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511 assert( bol->Opcode() == Op_Bool, "" ); |
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512 int cmp_op = bol->in(1)->Opcode(); |
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513 // It is expensive to generate flags from a float compare. |
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514 // Avoid duplicated float compare. |
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515 if( phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; |
| 0 | 516 |
| 517 // -------------- | |
| 518 // Now replace all Phis with CMOV's | |
| 519 Node *cmov_ctrl = iff->in(0); | |
| 520 uint flip = (lp->Opcode() == Op_IfTrue); | |
| 521 while( 1 ) { | |
| 522 PhiNode* phi = NULL; | |
| 523 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
| 524 Node *out = region->fast_out(i); | |
| 525 if (out->is_Phi()) { | |
| 526 phi = out->as_Phi(); | |
| 527 break; | |
| 528 } | |
| 529 } | |
| 530 if (phi == NULL) break; | |
| 531 #ifndef PRODUCT | |
| 532 if( PrintOpto && VerifyLoopOptimizations ) tty->print_cr("CMOV"); | |
| 533 #endif | |
| 534 // Move speculative ops | |
| 535 for( uint j = 1; j < region->req(); j++ ) { | |
| 536 Node *proj = region->in(j); | |
| 537 Node *inp = phi->in(j); | |
| 538 if (get_ctrl(inp) == proj) { // Found local op | |
| 539 #ifndef PRODUCT | |
| 540 if( PrintOpto && VerifyLoopOptimizations ) { | |
| 541 tty->print(" speculate: "); | |
| 542 inp->dump(); | |
| 543 } | |
| 544 #endif | |
| 545 set_ctrl(inp, cmov_ctrl); | |
| 546 } | |
| 547 } | |
| 548 Node *cmov = CMoveNode::make( C, cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi) ); | |
| 549 register_new_node( cmov, cmov_ctrl ); | |
| 550 _igvn.hash_delete(phi); | |
| 551 _igvn.subsume_node( phi, cmov ); | |
| 552 #ifndef PRODUCT | |
| 553 if( VerifyLoopOptimizations ) verify(); | |
| 554 #endif | |
| 555 } | |
| 556 | |
| 557 // The useless CFG diamond will fold up later; see the optimization in | |
| 558 // RegionNode::Ideal. | |
| 559 _igvn._worklist.push(region); | |
| 560 | |
| 561 return iff->in(1); | |
| 562 } | |
| 563 | |
| 564 //------------------------------split_if_with_blocks_pre----------------------- | |
| 565 // Do the real work in a non-recursive function. Data nodes want to be | |
| 566 // cloned in the pre-order so they can feed each other nicely. | |
| 567 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { | |
| 568 // Cloning these guys is unlikely to win | |
| 569 int n_op = n->Opcode(); | |
| 570 if( n_op == Op_MergeMem ) return n; | |
| 571 if( n->is_Proj() ) return n; | |
| 572 // Do not clone-up CmpFXXX variations, as these are always | |
| 573 // followed by a CmpI | |
| 574 if( n->is_Cmp() ) return n; | |
| 575 // Attempt to use a conditional move instead of a phi/branch | |
| 576 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { | |
| 577 Node *cmov = conditional_move( n ); | |
| 578 if( cmov ) return cmov; | |
| 579 } | |
| 580 if( n->is_CFG() || n_op == Op_StorePConditional || n_op == Op_StoreLConditional || n_op == Op_CompareAndSwapI || n_op == Op_CompareAndSwapL ||n_op == Op_CompareAndSwapP) return n; | |
| 581 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd | |
| 582 n_op == Op_Opaque2 ) { | |
| 583 if( !C->major_progress() ) // If chance of no more loop opts... | |
| 584 _igvn._worklist.push(n); // maybe we'll remove them | |
| 585 return n; | |
| 586 } | |
| 587 | |
| 588 if( n->is_Con() ) return n; // No cloning for Con nodes | |
| 589 | |
| 590 Node *n_ctrl = get_ctrl(n); | |
| 591 if( !n_ctrl ) return n; // Dead node | |
| 592 | |
| 593 // Attempt to remix address expressions for loop invariants | |
| 594 Node *m = remix_address_expressions( n ); | |
| 595 if( m ) return m; | |
| 596 | |
| 597 // Determine if the Node has inputs from some local Phi. | |
| 598 // Returns the block to clone thru. | |
| 599 Node *n_blk = has_local_phi_input( n ); | |
| 600 if( !n_blk ) return n; | |
| 601 // Do not clone the trip counter through on a CountedLoop | |
| 602 // (messes up the canonical shape). | |
| 603 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; | |
| 604 | |
| 605 // Check for having no control input; not pinned. Allow | |
| 606 // dominating control. | |
| 607 if( n->in(0) ) { | |
| 608 Node *dom = idom(n_blk); | |
| 609 if( dom_lca( n->in(0), dom ) != n->in(0) ) | |
| 610 return n; | |
| 611 } | |
| 612 // Policy: when is it profitable. You must get more wins than | |
| 613 // policy before it is considered profitable. Policy is usually 0, | |
| 614 // so 1 win is considered profitable. Big merges will require big | |
| 615 // cloning, so get a larger policy. | |
| 616 int policy = n_blk->req() >> 2; | |
| 617 | |
| 618 // If the loop is a candidate for range check elimination, | |
| 619 // delay splitting through it's phi until a later loop optimization | |
| 620 if (n_blk->is_CountedLoop()) { | |
| 621 IdealLoopTree *lp = get_loop(n_blk); | |
| 622 if (lp && lp->_rce_candidate) { | |
| 623 return n; | |
| 624 } | |
| 625 } | |
| 626 | |
| 627 // Use same limit as split_if_with_blocks_post | |
| 628 if( C->unique() > 35000 ) return n; // Method too big | |
| 629 | |
| 630 // Split 'n' through the merge point if it is profitable | |
| 631 Node *phi = split_thru_phi( n, n_blk, policy ); | |
| 632 if( !phi ) return n; | |
| 633 | |
| 634 // Found a Phi to split thru! | |
| 635 // Replace 'n' with the new phi | |
| 636 _igvn.hash_delete(n); | |
| 637 _igvn.subsume_node( n, phi ); | |
| 638 // Moved a load around the loop, 'en-registering' something. | |
| 639 if( n_blk->Opcode() == Op_Loop && n->is_Load() && | |
| 640 !phi->in(LoopNode::LoopBackControl)->is_Load() ) | |
| 641 C->set_major_progress(); | |
| 642 | |
| 643 return phi; | |
| 644 } | |
| 645 | |
| 646 static bool merge_point_too_heavy(Compile* C, Node* region) { | |
| 647 // Bail out if the region and its phis have too many users. | |
| 648 int weight = 0; | |
| 649 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
| 650 weight += region->fast_out(i)->outcnt(); | |
| 651 } | |
| 652 int nodes_left = MaxNodeLimit - C->unique(); | |
| 653 if (weight * 8 > nodes_left) { | |
| 654 #ifndef PRODUCT | |
| 655 if (PrintOpto) | |
| 656 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); | |
| 657 #endif | |
| 658 return true; | |
| 659 } else { | |
| 660 return false; | |
| 661 } | |
| 662 } | |
| 663 | |
| 664 #ifdef _LP64 | |
| 665 static bool merge_point_safe(Node* region) { | |
| 666 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode | |
| 667 // having a PhiNode input. This sidesteps the dangerous case where the split | |
| 668 // ConvI2LNode may become TOP if the input Value() does not | |
| 669 // overlap the ConvI2L range, leaving a node which may not dominate its | |
| 670 // uses. | |
| 671 // A better fix for this problem can be found in the BugTraq entry, but | |
| 672 // expediency for Mantis demands this hack. | |
| 673 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
| 674 Node* n = region->fast_out(i); | |
| 675 if (n->is_Phi()) { | |
| 676 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 677 Node* m = n->fast_out(j); | |
| 678 if (m->Opcode() == Op_ConvI2L) { | |
| 679 return false; | |
| 680 } | |
| 681 } | |
| 682 } | |
| 683 } | |
| 684 return true; | |
| 685 } | |
| 686 #endif | |
| 687 | |
| 688 | |
| 689 //------------------------------place_near_use--------------------------------- | |
| 690 // Place some computation next to use but not inside inner loops. | |
| 691 // For inner loop uses move it to the preheader area. | |
| 692 Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { | |
| 693 IdealLoopTree *u_loop = get_loop( useblock ); | |
| 694 return (u_loop->_irreducible || u_loop->_child) | |
| 695 ? useblock | |
| 696 : u_loop->_head->in(LoopNode::EntryControl); | |
| 697 } | |
| 698 | |
| 699 | |
| 700 //------------------------------split_if_with_blocks_post---------------------- | |
| 701 // Do the real work in a non-recursive function. CFG hackery wants to be | |
| 702 // in the post-order, so it can dirty the I-DOM info and not use the dirtied | |
| 703 // info. | |
| 704 void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) { | |
| 705 | |
| 706 // Cloning Cmp through Phi's involves the split-if transform. | |
| 707 // FastLock is not used by an If | |
| 708 if( n->is_Cmp() && !n->is_FastLock() ) { | |
| 709 if( C->unique() > 35000 ) return; // Method too big | |
| 710 | |
| 711 // Do not do 'split-if' if irreducible loops are present. | |
| 712 if( _has_irreducible_loops ) | |
| 713 return; | |
| 714 | |
| 715 Node *n_ctrl = get_ctrl(n); | |
| 716 // Determine if the Node has inputs from some local Phi. | |
| 717 // Returns the block to clone thru. | |
| 718 Node *n_blk = has_local_phi_input( n ); | |
| 719 if( n_blk != n_ctrl ) return; | |
| 720 | |
| 721 if( merge_point_too_heavy(C, n_ctrl) ) | |
| 722 return; | |
| 723 | |
| 724 if( n->outcnt() != 1 ) return; // Multiple bool's from 1 compare? | |
| 725 Node *bol = n->unique_out(); | |
| 726 assert( bol->is_Bool(), "expect a bool here" ); | |
| 727 if( bol->outcnt() != 1 ) return;// Multiple branches from 1 compare? | |
| 728 Node *iff = bol->unique_out(); | |
| 729 | |
| 730 // Check some safety conditions | |
| 731 if( iff->is_If() ) { // Classic split-if? | |
| 732 if( iff->in(0) != n_ctrl ) return; // Compare must be in same blk as if | |
| 733 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE | |
| 734 if( get_ctrl(iff->in(2)) == n_ctrl || | |
| 735 get_ctrl(iff->in(3)) == n_ctrl ) | |
| 736 return; // Inputs not yet split-up | |
| 737 if ( get_loop(n_ctrl) != get_loop(get_ctrl(iff)) ) { | |
| 738 return; // Loop-invar test gates loop-varying CMOVE | |
| 739 } | |
| 740 } else { | |
| 741 return; // some other kind of node, such as an Allocate | |
| 742 } | |
| 743 | |
| 744 // Do not do 'split-if' if some paths are dead. First do dead code | |
| 745 // elimination and then see if its still profitable. | |
| 746 for( uint i = 1; i < n_ctrl->req(); i++ ) | |
| 747 if( n_ctrl->in(i) == C->top() ) | |
| 748 return; | |
| 749 | |
| 750 // When is split-if profitable? Every 'win' on means some control flow | |
| 751 // goes dead, so it's almost always a win. | |
| 752 int policy = 0; | |
| 753 // If trying to do a 'Split-If' at the loop head, it is only | |
| 754 // profitable if the cmp folds up on BOTH paths. Otherwise we | |
| 755 // risk peeling a loop forever. | |
| 756 | |
| 757 // CNC - Disabled for now. Requires careful handling of loop | |
| 758 // body selection for the cloned code. Also, make sure we check | |
| 759 // for any input path not being in the same loop as n_ctrl. For | |
| 760 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' | |
| 761 // because the alternative loop entry points won't be converted | |
| 762 // into LoopNodes. | |
| 763 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
| 764 for( uint j = 1; j < n_ctrl->req(); j++ ) | |
| 765 if( get_loop(n_ctrl->in(j)) != n_loop ) | |
| 766 return; | |
| 767 | |
| 768 #ifdef _LP64 | |
| 769 // Check for safety of the merge point. | |
| 770 if( !merge_point_safe(n_ctrl) ) { | |
| 771 return; | |
| 772 } | |
| 773 #endif | |
| 774 | |
| 775 // Split compare 'n' through the merge point if it is profitable | |
| 776 Node *phi = split_thru_phi( n, n_ctrl, policy ); | |
| 777 if( !phi ) return; | |
| 778 | |
| 779 // Found a Phi to split thru! | |
| 780 // Replace 'n' with the new phi | |
| 781 _igvn.hash_delete(n); | |
| 782 _igvn.subsume_node( n, phi ); | |
| 783 | |
| 784 // Now split the bool up thru the phi | |
| 785 Node *bolphi = split_thru_phi( bol, n_ctrl, -1 ); | |
| 786 _igvn.hash_delete(bol); | |
| 787 _igvn.subsume_node( bol, bolphi ); | |
| 788 assert( iff->in(1) == bolphi, "" ); | |
| 789 if( bolphi->Value(&_igvn)->singleton() ) | |
| 790 return; | |
| 791 | |
| 792 // Conditional-move? Must split up now | |
| 793 if( !iff->is_If() ) { | |
| 794 Node *cmovphi = split_thru_phi( iff, n_ctrl, -1 ); | |
| 795 _igvn.hash_delete(iff); | |
| 796 _igvn.subsume_node( iff, cmovphi ); | |
| 797 return; | |
| 798 } | |
| 799 | |
| 800 // Now split the IF | |
| 801 do_split_if( iff ); | |
| 802 return; | |
| 803 } | |
| 804 | |
| 805 // Check for an IF ready to split; one that has its | |
| 806 // condition codes input coming from a Phi at the block start. | |
| 807 int n_op = n->Opcode(); | |
| 808 | |
| 809 // Check for an IF being dominated by another IF same test | |
| 810 if( n_op == Op_If ) { | |
| 811 Node *bol = n->in(1); | |
| 812 uint max = bol->outcnt(); | |
| 813 // Check for same test used more than once? | |
| 814 if( n_op == Op_If && max > 1 && bol->is_Bool() ) { | |
| 815 // Search up IDOMs to see if this IF is dominated. | |
| 816 Node *cutoff = get_ctrl(bol); | |
| 817 | |
| 818 // Now search up IDOMs till cutoff, looking for a dominating test | |
| 819 Node *prevdom = n; | |
| 820 Node *dom = idom(prevdom); | |
| 821 while( dom != cutoff ) { | |
| 822 if( dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom ) { | |
| 823 // Replace the dominated test with an obvious true or false. | |
| 824 // Place it on the IGVN worklist for later cleanup. | |
| 825 C->set_major_progress(); | |
| 826 dominated_by( prevdom, n ); | |
| 827 #ifndef PRODUCT | |
| 828 if( VerifyLoopOptimizations ) verify(); | |
| 829 #endif | |
| 830 return; | |
| 831 } | |
| 832 prevdom = dom; | |
| 833 dom = idom(prevdom); | |
| 834 } | |
| 835 } | |
| 836 } | |
| 837 | |
| 838 // See if a shared loop-varying computation has no loop-varying uses. | |
| 839 // Happens if something is only used for JVM state in uncommon trap exits, | |
| 840 // like various versions of induction variable+offset. Clone the | |
| 841 // computation per usage to allow it to sink out of the loop. | |
| 842 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) | |
| 843 Node *n_ctrl = get_ctrl(n); | |
| 844 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
| 845 if( n_loop != _ltree_root ) { | |
| 846 DUIterator_Fast imax, i = n->fast_outs(imax); | |
| 847 for (; i < imax; i++) { | |
| 848 Node* u = n->fast_out(i); | |
| 849 if( !has_ctrl(u) ) break; // Found control user | |
| 850 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); | |
| 851 if( u_loop == n_loop ) break; // Found loop-varying use | |
| 852 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop | |
| 853 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 | |
| 854 } | |
| 855 bool did_break = (i < imax); // Did we break out of the previous loop? | |
| 856 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! | |
| 857 Node *late_load_ctrl; | |
| 858 if (n->is_Load()) { | |
| 859 // If n is a load, get and save the result from get_late_ctrl(), | |
| 860 // to be later used in calculating the control for n's clones. | |
| 861 clear_dom_lca_tags(); | |
| 862 late_load_ctrl = get_late_ctrl(n, n_ctrl); | |
| 863 } | |
| 864 // If n is a load, and the late control is the same as the current | |
| 865 // control, then the cloning of n is a pointless exercise, because | |
| 866 // GVN will ensure that we end up where we started. | |
| 867 if (!n->is_Load() || late_load_ctrl != n_ctrl) { | |
| 868 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { | |
| 869 Node *u = n->last_out(j); // Clone private computation per use | |
| 870 _igvn.hash_delete(u); | |
| 871 _igvn._worklist.push(u); | |
| 872 Node *x = n->clone(); // Clone computation | |
| 873 Node *x_ctrl = NULL; | |
| 874 if( u->is_Phi() ) { | |
| 875 // Replace all uses of normal nodes. Replace Phi uses | |
| 876 // individually, so the seperate Nodes can sink down | |
| 877 // different paths. | |
| 878 uint k = 1; | |
| 879 while( u->in(k) != n ) k++; | |
| 880 u->set_req( k, x ); | |
| 881 // x goes next to Phi input path | |
| 882 x_ctrl = u->in(0)->in(k); | |
| 883 --j; | |
| 884 } else { // Normal use | |
| 885 // Replace all uses | |
| 886 for( uint k = 0; k < u->req(); k++ ) { | |
| 887 if( u->in(k) == n ) { | |
| 888 u->set_req( k, x ); | |
| 889 --j; | |
| 890 } | |
| 891 } | |
| 892 x_ctrl = get_ctrl(u); | |
| 893 } | |
| 894 | |
| 895 // Find control for 'x' next to use but not inside inner loops. | |
| 896 // For inner loop uses get the preheader area. | |
| 897 x_ctrl = place_near_use(x_ctrl); | |
| 898 | |
| 899 if (n->is_Load()) { | |
| 900 // For loads, add a control edge to a CFG node outside of the loop | |
| 901 // to force them to not combine and return back inside the loop | |
| 902 // during GVN optimization (4641526). | |
| 903 // | |
| 904 // Because we are setting the actual control input, factor in | |
| 905 // the result from get_late_ctrl() so we respect any | |
| 906 // anti-dependences. (6233005). | |
| 907 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); | |
| 908 | |
| 909 // Don't allow the control input to be a CFG splitting node. | |
| 910 // Such nodes should only have ProjNodes as outs, e.g. IfNode | |
| 911 // should only have IfTrueNode and IfFalseNode (4985384). | |
| 912 x_ctrl = find_non_split_ctrl(x_ctrl); | |
| 913 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); | |
| 914 | |
| 915 x->set_req(0, x_ctrl); | |
| 916 } | |
| 917 register_new_node(x, x_ctrl); | |
| 918 | |
| 919 // Some institutional knowledge is needed here: 'x' is | |
| 920 // yanked because if the optimizer runs GVN on it all the | |
| 921 // cloned x's will common up and undo this optimization and | |
| 922 // be forced back in the loop. This is annoying because it | |
| 923 // makes +VerifyOpto report false-positives on progress. I | |
| 924 // tried setting control edges on the x's to force them to | |
| 925 // not combine, but the matching gets worried when it tries | |
| 926 // to fold a StoreP and an AddP together (as part of an | |
| 927 // address expression) and the AddP and StoreP have | |
| 928 // different controls. | |
| 929 if( !x->is_Load() ) _igvn._worklist.yank(x); | |
| 930 } | |
| 931 _igvn.remove_dead_node(n); | |
| 932 } | |
| 933 } | |
| 934 } | |
| 935 } | |
| 936 | |
| 937 // Check for Opaque2's who's loop has disappeared - who's input is in the | |
| 938 // same loop nest as their output. Remove 'em, they are no longer useful. | |
| 939 if( n_op == Op_Opaque2 && | |
| 940 n->in(1) != NULL && | |
| 941 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { | |
| 942 _igvn.add_users_to_worklist(n); | |
| 943 _igvn.hash_delete(n); | |
| 944 _igvn.subsume_node( n, n->in(1) ); | |
| 945 } | |
| 946 } | |
| 947 | |
| 948 //------------------------------split_if_with_blocks--------------------------- | |
| 949 // Check for aggressive application of 'split-if' optimization, | |
| 950 // using basic block level info. | |
| 951 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { | |
| 952 Node *n = C->root(); | |
| 953 visited.set(n->_idx); // first, mark node as visited | |
| 954 // Do pre-visit work for root | |
| 955 n = split_if_with_blocks_pre( n ); | |
| 956 uint cnt = n->outcnt(); | |
| 957 uint i = 0; | |
| 958 while (true) { | |
| 959 // Visit all children | |
| 960 if (i < cnt) { | |
| 961 Node* use = n->raw_out(i); | |
| 962 ++i; | |
| 963 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { | |
| 964 // Now do pre-visit work for this use | |
| 965 use = split_if_with_blocks_pre( use ); | |
| 966 nstack.push(n, i); // Save parent and next use's index. | |
| 967 n = use; // Process all children of current use. | |
| 968 cnt = use->outcnt(); | |
| 969 i = 0; | |
| 970 } | |
| 971 } | |
| 972 else { | |
| 973 // All of n's children have been processed, complete post-processing. | |
| 974 if (cnt != 0 && !n->is_Con()) { | |
| 975 assert(has_node(n), "no dead nodes"); | |
| 976 split_if_with_blocks_post( n ); | |
| 977 } | |
| 978 if (nstack.is_empty()) { | |
| 979 // Finished all nodes on stack. | |
| 980 break; | |
| 981 } | |
| 982 // Get saved parent node and next use's index. Visit the rest of uses. | |
| 983 n = nstack.node(); | |
| 984 cnt = n->outcnt(); | |
| 985 i = nstack.index(); | |
| 986 nstack.pop(); | |
| 987 } | |
| 988 } | |
| 989 } | |
| 990 | |
| 991 | |
| 992 //============================================================================= | |
| 993 // | |
| 994 // C L O N E A L O O P B O D Y | |
| 995 // | |
| 996 | |
| 997 //------------------------------clone_iff-------------------------------------- | |
| 998 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
| 999 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
| 1000 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
| 1001 // through the Phi recursively, and return a Bool. | |
| 1002 BoolNode *PhaseIdealLoop::clone_iff( PhiNode *phi, IdealLoopTree *loop ) { | |
| 1003 | |
| 1004 // Convert this Phi into a Phi merging Bools | |
| 1005 uint i; | |
| 1006 for( i = 1; i < phi->req(); i++ ) { | |
| 1007 Node *b = phi->in(i); | |
| 1008 if( b->is_Phi() ) { | |
| 1009 _igvn.hash_delete(phi); | |
| 1010 _igvn._worklist.push(phi); | |
| 1011 phi->set_req(i, clone_iff( b->as_Phi(), loop )); | |
| 1012 } else { | |
| 1013 assert( b->is_Bool(), "" ); | |
| 1014 } | |
| 1015 } | |
| 1016 | |
| 1017 Node *sample_bool = phi->in(1); | |
| 1018 Node *sample_cmp = sample_bool->in(1); | |
| 1019 | |
| 1020 // Make Phis to merge the Cmp's inputs. | |
| 1021 int size = phi->in(0)->req(); | |
| 1022 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
| 1023 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
| 1024 for( i = 1; i < phi->req(); i++ ) { | |
| 1025 Node *n1 = phi->in(i)->in(1)->in(1); | |
| 1026 Node *n2 = phi->in(i)->in(1)->in(2); | |
| 1027 phi1->set_req( i, n1 ); | |
| 1028 phi2->set_req( i, n2 ); | |
| 1029 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
| 1030 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
| 1031 } | |
| 1032 // See if these Phis have been made before. | |
| 1033 // Register with optimizer | |
| 1034 Node *hit1 = _igvn.hash_find_insert(phi1); | |
| 1035 if( hit1 ) { // Hit, toss just made Phi | |
| 1036 _igvn.remove_dead_node(phi1); // Remove new phi | |
| 1037 assert( hit1->is_Phi(), "" ); | |
| 1038 phi1 = (PhiNode*)hit1; // Use existing phi | |
| 1039 } else { // Miss | |
| 1040 _igvn.register_new_node_with_optimizer(phi1); | |
| 1041 } | |
| 1042 Node *hit2 = _igvn.hash_find_insert(phi2); | |
| 1043 if( hit2 ) { // Hit, toss just made Phi | |
| 1044 _igvn.remove_dead_node(phi2); // Remove new phi | |
| 1045 assert( hit2->is_Phi(), "" ); | |
| 1046 phi2 = (PhiNode*)hit2; // Use existing phi | |
| 1047 } else { // Miss | |
| 1048 _igvn.register_new_node_with_optimizer(phi2); | |
| 1049 } | |
| 1050 // Register Phis with loop/block info | |
| 1051 set_ctrl(phi1, phi->in(0)); | |
| 1052 set_ctrl(phi2, phi->in(0)); | |
| 1053 // Make a new Cmp | |
| 1054 Node *cmp = sample_cmp->clone(); | |
| 1055 cmp->set_req( 1, phi1 ); | |
| 1056 cmp->set_req( 2, phi2 ); | |
| 1057 _igvn.register_new_node_with_optimizer(cmp); | |
| 1058 set_ctrl(cmp, phi->in(0)); | |
| 1059 | |
| 1060 // Make a new Bool | |
| 1061 Node *b = sample_bool->clone(); | |
| 1062 b->set_req(1,cmp); | |
| 1063 _igvn.register_new_node_with_optimizer(b); | |
| 1064 set_ctrl(b, phi->in(0)); | |
| 1065 | |
| 1066 assert( b->is_Bool(), "" ); | |
| 1067 return (BoolNode*)b; | |
| 1068 } | |
| 1069 | |
| 1070 //------------------------------clone_bool------------------------------------- | |
| 1071 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
| 1072 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
| 1073 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
| 1074 // through the Phi recursively, and return a Bool. | |
| 1075 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { | |
| 1076 uint i; | |
| 1077 // Convert this Phi into a Phi merging Bools | |
| 1078 for( i = 1; i < phi->req(); i++ ) { | |
| 1079 Node *b = phi->in(i); | |
| 1080 if( b->is_Phi() ) { | |
| 1081 _igvn.hash_delete(phi); | |
| 1082 _igvn._worklist.push(phi); | |
| 1083 phi->set_req(i, clone_bool( b->as_Phi(), loop )); | |
| 1084 } else { | |
| 1085 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); | |
| 1086 } | |
| 1087 } | |
| 1088 | |
| 1089 Node *sample_cmp = phi->in(1); | |
| 1090 | |
| 1091 // Make Phis to merge the Cmp's inputs. | |
| 1092 int size = phi->in(0)->req(); | |
| 1093 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
| 1094 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
| 1095 for( uint j = 1; j < phi->req(); j++ ) { | |
| 1096 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP | |
| 1097 Node *n1, *n2; | |
| 1098 if( cmp_top->is_Cmp() ) { | |
| 1099 n1 = cmp_top->in(1); | |
| 1100 n2 = cmp_top->in(2); | |
| 1101 } else { | |
| 1102 n1 = n2 = cmp_top; | |
| 1103 } | |
| 1104 phi1->set_req( j, n1 ); | |
| 1105 phi2->set_req( j, n2 ); | |
| 1106 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
| 1107 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
| 1108 } | |
| 1109 | |
| 1110 // See if these Phis have been made before. | |
| 1111 // Register with optimizer | |
| 1112 Node *hit1 = _igvn.hash_find_insert(phi1); | |
| 1113 if( hit1 ) { // Hit, toss just made Phi | |
| 1114 _igvn.remove_dead_node(phi1); // Remove new phi | |
| 1115 assert( hit1->is_Phi(), "" ); | |
| 1116 phi1 = (PhiNode*)hit1; // Use existing phi | |
| 1117 } else { // Miss | |
| 1118 _igvn.register_new_node_with_optimizer(phi1); | |
| 1119 } | |
| 1120 Node *hit2 = _igvn.hash_find_insert(phi2); | |
| 1121 if( hit2 ) { // Hit, toss just made Phi | |
| 1122 _igvn.remove_dead_node(phi2); // Remove new phi | |
| 1123 assert( hit2->is_Phi(), "" ); | |
| 1124 phi2 = (PhiNode*)hit2; // Use existing phi | |
| 1125 } else { // Miss | |
| 1126 _igvn.register_new_node_with_optimizer(phi2); | |
| 1127 } | |
| 1128 // Register Phis with loop/block info | |
| 1129 set_ctrl(phi1, phi->in(0)); | |
| 1130 set_ctrl(phi2, phi->in(0)); | |
| 1131 // Make a new Cmp | |
| 1132 Node *cmp = sample_cmp->clone(); | |
| 1133 cmp->set_req( 1, phi1 ); | |
| 1134 cmp->set_req( 2, phi2 ); | |
| 1135 _igvn.register_new_node_with_optimizer(cmp); | |
| 1136 set_ctrl(cmp, phi->in(0)); | |
| 1137 | |
| 1138 assert( cmp->is_Cmp(), "" ); | |
| 1139 return (CmpNode*)cmp; | |
| 1140 } | |
| 1141 | |
| 1142 //------------------------------sink_use--------------------------------------- | |
| 1143 // If 'use' was in the loop-exit block, it now needs to be sunk | |
| 1144 // below the post-loop merge point. | |
| 1145 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { | |
| 1146 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { | |
| 1147 set_ctrl(use, post_loop); | |
| 1148 for (DUIterator j = use->outs(); use->has_out(j); j++) | |
| 1149 sink_use(use->out(j), post_loop); | |
| 1150 } | |
| 1151 } | |
| 1152 | |
| 1153 //------------------------------clone_loop------------------------------------- | |
| 1154 // | |
| 1155 // C L O N E A L O O P B O D Y | |
| 1156 // | |
| 1157 // This is the basic building block of the loop optimizations. It clones an | |
| 1158 // entire loop body. It makes an old_new loop body mapping; with this mapping | |
| 1159 // you can find the new-loop equivalent to an old-loop node. All new-loop | |
| 1160 // nodes are exactly equal to their old-loop counterparts, all edges are the | |
| 1161 // same. All exits from the old-loop now have a RegionNode that merges the | |
| 1162 // equivalent new-loop path. This is true even for the normal "loop-exit" | |
| 1163 // condition. All uses of loop-invariant old-loop values now come from (one | |
| 1164 // or more) Phis that merge their new-loop equivalents. | |
| 1165 // | |
| 1166 // This operation leaves the graph in an illegal state: there are two valid | |
| 1167 // control edges coming from the loop pre-header to both loop bodies. I'll | |
| 1168 // definitely have to hack the graph after running this transform. | |
| 1169 // | |
| 1170 // From this building block I will further edit edges to perform loop peeling | |
| 1171 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. | |
| 1172 // | |
| 1173 // Parameter side_by_size_idom: | |
| 1174 // When side_by_size_idom is NULL, the dominator tree is constructed for | |
| 1175 // the clone loop to dominate the original. Used in construction of | |
| 1176 // pre-main-post loop sequence. | |
| 1177 // When nonnull, the clone and original are side-by-side, both are | |
| 1178 // dominated by the side_by_side_idom node. Used in construction of | |
| 1179 // unswitched loops. | |
| 1180 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, | |
| 1181 Node* side_by_side_idom) { | |
| 1182 | |
| 1183 // Step 1: Clone the loop body. Make the old->new mapping. | |
| 1184 uint i; | |
| 1185 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1186 Node *old = loop->_body.at(i); | |
| 1187 Node *nnn = old->clone(); | |
| 1188 old_new.map( old->_idx, nnn ); | |
| 1189 _igvn.register_new_node_with_optimizer(nnn); | |
| 1190 } | |
| 1191 | |
| 1192 | |
| 1193 // Step 2: Fix the edges in the new body. If the old input is outside the | |
| 1194 // loop use it. If the old input is INside the loop, use the corresponding | |
| 1195 // new node instead. | |
| 1196 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1197 Node *old = loop->_body.at(i); | |
| 1198 Node *nnn = old_new[old->_idx]; | |
| 1199 // Fix CFG/Loop controlling the new node | |
| 1200 if (has_ctrl(old)) { | |
| 1201 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); | |
| 1202 } else { | |
| 1203 set_loop(nnn, loop->_parent); | |
| 1204 if (old->outcnt() > 0) { | |
| 1205 set_idom( nnn, old_new[idom(old)->_idx], dd ); | |
| 1206 } | |
| 1207 } | |
| 1208 // Correct edges to the new node | |
| 1209 for( uint j = 0; j < nnn->req(); j++ ) { | |
| 1210 Node *n = nnn->in(j); | |
| 1211 if( n ) { | |
| 1212 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); | |
| 1213 if( loop->is_member( old_in_loop ) ) | |
| 1214 nnn->set_req(j, old_new[n->_idx]); | |
| 1215 } | |
| 1216 } | |
| 1217 _igvn.hash_find_insert(nnn); | |
| 1218 } | |
| 1219 Node *newhead = old_new[loop->_head->_idx]; | |
| 1220 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); | |
| 1221 | |
| 1222 | |
| 1223 // Step 3: Now fix control uses. Loop varying control uses have already | |
| 1224 // been fixed up (as part of all input edges in Step 2). Loop invariant | |
| 1225 // control uses must be either an IfFalse or an IfTrue. Make a merge | |
| 1226 // point to merge the old and new IfFalse/IfTrue nodes; make the use | |
| 1227 // refer to this. | |
| 1228 ResourceArea *area = Thread::current()->resource_area(); | |
| 1229 Node_List worklist(area); | |
| 1230 uint new_counter = C->unique(); | |
| 1231 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1232 Node* old = loop->_body.at(i); | |
| 1233 if( !old->is_CFG() ) continue; | |
| 1234 Node* nnn = old_new[old->_idx]; | |
| 1235 | |
| 1236 // Copy uses to a worklist, so I can munge the def-use info | |
| 1237 // with impunity. | |
| 1238 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
| 1239 worklist.push(old->fast_out(j)); | |
| 1240 | |
| 1241 while( worklist.size() ) { // Visit all uses | |
| 1242 Node *use = worklist.pop(); | |
| 1243 if (!has_node(use)) continue; // Ignore dead nodes | |
| 1244 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
| 1245 if( !loop->is_member( use_loop ) && use->is_CFG() ) { | |
| 1246 // Both OLD and USE are CFG nodes here. | |
| 1247 assert( use->is_Proj(), "" ); | |
| 1248 | |
| 1249 // Clone the loop exit control projection | |
| 1250 Node *newuse = use->clone(); | |
| 1251 newuse->set_req(0,nnn); | |
| 1252 _igvn.register_new_node_with_optimizer(newuse); | |
| 1253 set_loop(newuse, use_loop); | |
| 1254 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); | |
| 1255 | |
| 1256 // We need a Region to merge the exit from the peeled body and the | |
| 1257 // exit from the old loop body. | |
| 1258 RegionNode *r = new (C, 3) RegionNode(3); | |
| 1259 // Map the old use to the new merge point | |
| 1260 old_new.map( use->_idx, r ); | |
| 1261 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); | |
| 1262 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); | |
| 1263 | |
| 1264 // The original user of 'use' uses 'r' instead. | |
| 1265 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { | |
| 1266 Node* useuse = use->last_out(l); | |
| 1267 _igvn.hash_delete(useuse); | |
| 1268 _igvn._worklist.push(useuse); | |
| 1269 uint uses_found = 0; | |
| 1270 if( useuse->in(0) == use ) { | |
| 1271 useuse->set_req(0, r); | |
| 1272 uses_found++; | |
| 1273 if( useuse->is_CFG() ) { | |
| 1274 assert( dom_depth(useuse) > dd_r, "" ); | |
| 1275 set_idom(useuse, r, dom_depth(useuse)); | |
| 1276 } | |
| 1277 } | |
| 1278 for( uint k = 1; k < useuse->req(); k++ ) { | |
| 1279 if( useuse->in(k) == use ) { | |
| 1280 useuse->set_req(k, r); | |
| 1281 uses_found++; | |
| 1282 } | |
| 1283 } | |
| 1284 l -= uses_found; // we deleted 1 or more copies of this edge | |
| 1285 } | |
| 1286 | |
| 1287 // Now finish up 'r' | |
| 1288 r->set_req( 1, newuse ); | |
| 1289 r->set_req( 2, use ); | |
| 1290 _igvn.register_new_node_with_optimizer(r); | |
| 1291 set_loop(r, use_loop); | |
| 1292 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); | |
| 1293 } // End of if a loop-exit test | |
| 1294 } | |
| 1295 } | |
| 1296 | |
| 1297 // Step 4: If loop-invariant use is not control, it must be dominated by a | |
| 1298 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region | |
| 1299 // there if needed. Make a Phi there merging old and new used values. | |
| 1300 Node_List *split_if_set = NULL; | |
| 1301 Node_List *split_bool_set = NULL; | |
| 1302 Node_List *split_cex_set = NULL; | |
| 1303 for( i = 0; i < loop->_body.size(); i++ ) { | |
| 1304 Node* old = loop->_body.at(i); | |
| 1305 Node* nnn = old_new[old->_idx]; | |
| 1306 // Copy uses to a worklist, so I can munge the def-use info | |
| 1307 // with impunity. | |
| 1308 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
| 1309 worklist.push(old->fast_out(j)); | |
| 1310 | |
| 1311 while( worklist.size() ) { | |
| 1312 Node *use = worklist.pop(); | |
| 1313 if (!has_node(use)) continue; // Ignore dead nodes | |
| 1314 if (use->in(0) == C->top()) continue; | |
| 1315 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
| 1316 // Check for data-use outside of loop - at least one of OLD or USE | |
| 1317 // must not be a CFG node. | |
| 1318 if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { | |
| 1319 | |
| 1320 // If the Data use is an IF, that means we have an IF outside of the | |
| 1321 // loop that is switching on a condition that is set inside of the | |
| 1322 // loop. Happens if people set a loop-exit flag; then test the flag | |
| 1323 // in the loop to break the loop, then test is again outside of the | |
| 1324 // loop to determine which way the loop exited. | |
| 1325 if( use->is_If() || use->is_CMove() ) { | |
| 1326 // Since this code is highly unlikely, we lazily build the worklist | |
| 1327 // of such Nodes to go split. | |
| 1328 if( !split_if_set ) | |
| 1329 split_if_set = new Node_List(area); | |
| 1330 split_if_set->push(use); | |
| 1331 } | |
| 1332 if( use->is_Bool() ) { | |
| 1333 if( !split_bool_set ) | |
| 1334 split_bool_set = new Node_List(area); | |
| 1335 split_bool_set->push(use); | |
| 1336 } | |
| 1337 if( use->Opcode() == Op_CreateEx ) { | |
| 1338 if( !split_cex_set ) | |
| 1339 split_cex_set = new Node_List(area); | |
| 1340 split_cex_set->push(use); | |
| 1341 } | |
| 1342 | |
| 1343 | |
| 1344 // Get "block" use is in | |
| 1345 uint idx = 0; | |
| 1346 while( use->in(idx) != old ) idx++; | |
| 1347 Node *prev = use->is_CFG() ? use : get_ctrl(use); | |
| 1348 assert( !loop->is_member( get_loop( prev ) ), "" ); | |
| 1349 Node *cfg = prev->_idx >= new_counter | |
| 1350 ? prev->in(2) | |
| 1351 : idom(prev); | |
| 1352 if( use->is_Phi() ) // Phi use is in prior block | |
| 1353 cfg = prev->in(idx); // NOT in block of Phi itself | |
| 1354 if (cfg->is_top()) { // Use is dead? | |
| 1355 _igvn.hash_delete(use); | |
| 1356 _igvn._worklist.push(use); | |
| 1357 use->set_req(idx, C->top()); | |
| 1358 continue; | |
| 1359 } | |
| 1360 | |
| 1361 while( !loop->is_member( get_loop( cfg ) ) ) { | |
| 1362 prev = cfg; | |
| 1363 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); | |
| 1364 } | |
| 1365 // If the use occurs after merging several exits from the loop, then | |
| 1366 // old value must have dominated all those exits. Since the same old | |
| 1367 // value was used on all those exits we did not need a Phi at this | |
| 1368 // merge point. NOW we do need a Phi here. Each loop exit value | |
| 1369 // is now merged with the peeled body exit; each exit gets its own | |
| 1370 // private Phi and those Phis need to be merged here. | |
| 1371 Node *phi; | |
| 1372 if( prev->is_Region() ) { | |
| 1373 if( idx == 0 ) { // Updating control edge? | |
| 1374 phi = prev; // Just use existing control | |
| 1375 } else { // Else need a new Phi | |
| 1376 phi = PhiNode::make( prev, old ); | |
| 1377 // Now recursively fix up the new uses of old! | |
| 1378 for( uint i = 1; i < prev->req(); i++ ) { | |
| 1379 worklist.push(phi); // Onto worklist once for each 'old' input | |
| 1380 } | |
| 1381 } | |
| 1382 } else { | |
| 1383 // Get new RegionNode merging old and new loop exits | |
| 1384 prev = old_new[prev->_idx]; | |
| 1385 assert( prev, "just made this in step 7" ); | |
| 1386 if( idx == 0 ) { // Updating control edge? | |
| 1387 phi = prev; // Just use existing control | |
| 1388 } else { // Else need a new Phi | |
| 1389 // Make a new Phi merging data values properly | |
| 1390 phi = PhiNode::make( prev, old ); | |
| 1391 phi->set_req( 1, nnn ); | |
| 1392 } | |
| 1393 } | |
| 1394 // If inserting a new Phi, check for prior hits | |
| 1395 if( idx != 0 ) { | |
| 1396 Node *hit = _igvn.hash_find_insert(phi); | |
| 1397 if( hit == NULL ) { | |
| 1398 _igvn.register_new_node_with_optimizer(phi); // Register new phi | |
| 1399 } else { // or | |
| 1400 // Remove the new phi from the graph and use the hit | |
| 1401 _igvn.remove_dead_node(phi); | |
| 1402 phi = hit; // Use existing phi | |
| 1403 } | |
| 1404 set_ctrl(phi, prev); | |
| 1405 } | |
| 1406 // Make 'use' use the Phi instead of the old loop body exit value | |
| 1407 _igvn.hash_delete(use); | |
| 1408 _igvn._worklist.push(use); | |
| 1409 use->set_req(idx, phi); | |
| 1410 if( use->_idx >= new_counter ) { // If updating new phis | |
| 1411 // Not needed for correctness, but prevents a weak assert | |
| 1412 // in AddPNode from tripping (when we end up with different | |
| 1413 // base & derived Phis that will become the same after | |
| 1414 // IGVN does CSE). | |
| 1415 Node *hit = _igvn.hash_find_insert(use); | |
| 1416 if( hit ) // Go ahead and re-hash for hits. | |
| 1417 _igvn.subsume_node( use, hit ); | |
| 1418 } | |
| 1419 | |
| 1420 // If 'use' was in the loop-exit block, it now needs to be sunk | |
| 1421 // below the post-loop merge point. | |
| 1422 sink_use( use, prev ); | |
| 1423 } | |
| 1424 } | |
| 1425 } | |
| 1426 | |
| 1427 // Check for IFs that need splitting/cloning. Happens if an IF outside of | |
| 1428 // the loop uses a condition set in the loop. The original IF probably | |
| 1429 // takes control from one or more OLD Regions (which in turn get from NEW | |
| 1430 // Regions). In any case, there will be a set of Phis for each merge point | |
| 1431 // from the IF up to where the original BOOL def exists the loop. | |
| 1432 if( split_if_set ) { | |
| 1433 while( split_if_set->size() ) { | |
| 1434 Node *iff = split_if_set->pop(); | |
| 1435 if( iff->in(1)->is_Phi() ) { | |
| 1436 BoolNode *b = clone_iff( iff->in(1)->as_Phi(), loop ); | |
| 1437 _igvn.hash_delete(iff); | |
| 1438 _igvn._worklist.push(iff); | |
| 1439 iff->set_req(1, b); | |
| 1440 } | |
| 1441 } | |
| 1442 } | |
| 1443 if( split_bool_set ) { | |
| 1444 while( split_bool_set->size() ) { | |
| 1445 Node *b = split_bool_set->pop(); | |
| 1446 Node *phi = b->in(1); | |
| 1447 assert( phi->is_Phi(), "" ); | |
| 1448 CmpNode *cmp = clone_bool( (PhiNode*)phi, loop ); | |
| 1449 _igvn.hash_delete(b); | |
| 1450 _igvn._worklist.push(b); | |
| 1451 b->set_req(1, cmp); | |
| 1452 } | |
| 1453 } | |
| 1454 if( split_cex_set ) { | |
| 1455 while( split_cex_set->size() ) { | |
| 1456 Node *b = split_cex_set->pop(); | |
| 1457 assert( b->in(0)->is_Region(), "" ); | |
| 1458 assert( b->in(1)->is_Phi(), "" ); | |
| 1459 assert( b->in(0)->in(0) == b->in(1)->in(0), "" ); | |
| 1460 split_up( b, b->in(0), NULL ); | |
| 1461 } | |
| 1462 } | |
| 1463 | |
| 1464 } | |
| 1465 | |
| 1466 | |
| 1467 //---------------------- stride_of_possible_iv ------------------------------------- | |
| 1468 // Looks for an iff/bool/comp with one operand of the compare | |
| 1469 // being a cycle involving an add and a phi, | |
| 1470 // with an optional truncation (left-shift followed by a right-shift) | |
| 1471 // of the add. Returns zero if not an iv. | |
| 1472 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { | |
| 1473 Node* trunc1 = NULL; | |
| 1474 Node* trunc2 = NULL; | |
| 1475 const TypeInt* ttype = NULL; | |
| 1476 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { | |
| 1477 return 0; | |
| 1478 } | |
| 1479 BoolNode* bl = iff->in(1)->as_Bool(); | |
| 1480 Node* cmp = bl->in(1); | |
| 1481 if (!cmp || cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU) { | |
| 1482 return 0; | |
| 1483 } | |
| 1484 // Must have an invariant operand | |
| 1485 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { | |
| 1486 return 0; | |
| 1487 } | |
| 1488 Node* add2 = NULL; | |
| 1489 Node* cmp1 = cmp->in(1); | |
| 1490 if (cmp1->is_Phi()) { | |
| 1491 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) | |
| 1492 Node* phi = cmp1; | |
| 1493 for (uint i = 1; i < phi->req(); i++) { | |
| 1494 Node* in = phi->in(i); | |
| 1495 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, | |
| 1496 &trunc1, &trunc2, &ttype); | |
| 1497 if (add && add->in(1) == phi) { | |
| 1498 add2 = add->in(2); | |
| 1499 break; | |
| 1500 } | |
| 1501 } | |
| 1502 } else { | |
| 1503 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) | |
| 1504 Node* addtrunc = cmp1; | |
| 1505 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, | |
| 1506 &trunc1, &trunc2, &ttype); | |
| 1507 if (add && add->in(1)->is_Phi()) { | |
| 1508 Node* phi = add->in(1); | |
| 1509 for (uint i = 1; i < phi->req(); i++) { | |
| 1510 if (phi->in(i) == addtrunc) { | |
| 1511 add2 = add->in(2); | |
| 1512 break; | |
| 1513 } | |
| 1514 } | |
| 1515 } | |
| 1516 } | |
| 1517 if (add2 != NULL) { | |
| 1518 const TypeInt* add2t = _igvn.type(add2)->is_int(); | |
| 1519 if (add2t->is_con()) { | |
| 1520 return add2t->get_con(); | |
| 1521 } | |
| 1522 } | |
| 1523 return 0; | |
| 1524 } | |
| 1525 | |
| 1526 | |
| 1527 //---------------------- stay_in_loop ------------------------------------- | |
| 1528 // Return the (unique) control output node that's in the loop (if it exists.) | |
| 1529 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { | |
| 1530 Node* unique = NULL; | |
| 1531 if (!n) return NULL; | |
| 1532 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { | |
| 1533 Node* use = n->fast_out(i); | |
| 1534 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { | |
| 1535 if (unique != NULL) { | |
| 1536 return NULL; | |
| 1537 } | |
| 1538 unique = use; | |
| 1539 } | |
| 1540 } | |
| 1541 return unique; | |
| 1542 } | |
| 1543 | |
| 1544 //------------------------------ register_node ------------------------------------- | |
| 1545 // Utility to register node "n" with PhaseIdealLoop | |
| 1546 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { | |
| 1547 _igvn.register_new_node_with_optimizer(n); | |
| 1548 loop->_body.push(n); | |
| 1549 if (n->is_CFG()) { | |
| 1550 set_loop(n, loop); | |
| 1551 set_idom(n, pred, ddepth); | |
| 1552 } else { | |
| 1553 set_ctrl(n, pred); | |
| 1554 } | |
| 1555 } | |
| 1556 | |
| 1557 //------------------------------ proj_clone ------------------------------------- | |
| 1558 // Utility to create an if-projection | |
| 1559 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { | |
| 1560 ProjNode* c = p->clone()->as_Proj(); | |
| 1561 c->set_req(0, iff); | |
| 1562 return c; | |
| 1563 } | |
| 1564 | |
| 1565 //------------------------------ short_circuit_if ------------------------------------- | |
| 1566 // Force the iff control output to be the live_proj | |
| 1567 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { | |
| 1568 int proj_con = live_proj->_con; | |
| 1569 assert(proj_con == 0 || proj_con == 1, "false or true projection"); | |
| 1570 Node *con = _igvn.intcon(proj_con); | |
| 1571 set_ctrl(con, C->root()); | |
| 1572 if (iff) { | |
| 1573 iff->set_req(1, con); | |
| 1574 } | |
| 1575 return con; | |
| 1576 } | |
| 1577 | |
| 1578 //------------------------------ insert_if_before_proj ------------------------------------- | |
| 1579 // Insert a new if before an if projection (* - new node) | |
| 1580 // | |
| 1581 // before | |
| 1582 // if(test) | |
| 1583 // / \ | |
| 1584 // v v | |
| 1585 // other-proj proj (arg) | |
| 1586 // | |
| 1587 // after | |
| 1588 // if(test) | |
| 1589 // / \ | |
| 1590 // / v | |
| 1591 // | * proj-clone | |
| 1592 // v | | |
| 1593 // other-proj v | |
| 1594 // * new_if(relop(cmp[IU](left,right))) | |
| 1595 // / \ | |
| 1596 // v v | |
| 1597 // * new-proj proj | |
| 1598 // (returned) | |
| 1599 // | |
| 1600 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { | |
| 1601 IfNode* iff = proj->in(0)->as_If(); | |
| 1602 IdealLoopTree *loop = get_loop(proj); | |
| 1603 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
| 1604 int ddepth = dom_depth(proj); | |
| 1605 | |
| 1606 _igvn.hash_delete(iff); | |
| 1607 _igvn._worklist.push(iff); | |
| 1608 _igvn.hash_delete(proj); | |
| 1609 _igvn._worklist.push(proj); | |
| 1610 | |
| 1611 proj->set_req(0, NULL); // temporary disconnect | |
| 1612 ProjNode* proj2 = proj_clone(proj, iff); | |
| 1613 register_node(proj2, loop, iff, ddepth); | |
| 1614 | |
| 1615 Node* cmp = Signed ? (Node*) new (C,3)CmpINode(left, right) : (Node*) new (C,3)CmpUNode(left, right); | |
| 1616 register_node(cmp, loop, proj2, ddepth); | |
| 1617 | |
| 1618 BoolNode* bol = new (C,2)BoolNode(cmp, relop); | |
| 1619 register_node(bol, loop, proj2, ddepth); | |
| 1620 | |
| 1621 IfNode* new_if = new (C,2)IfNode(proj2, bol, iff->_prob, iff->_fcnt); | |
| 1622 register_node(new_if, loop, proj2, ddepth); | |
| 1623 | |
| 1624 proj->set_req(0, new_if); // reattach | |
| 1625 set_idom(proj, new_if, ddepth); | |
| 1626 | |
| 1627 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); | |
| 1628 register_node(new_exit, get_loop(other_proj), new_if, ddepth); | |
| 1629 | |
| 1630 return new_exit; | |
| 1631 } | |
| 1632 | |
| 1633 //------------------------------ insert_region_before_proj ------------------------------------- | |
| 1634 // Insert a region before an if projection (* - new node) | |
| 1635 // | |
| 1636 // before | |
| 1637 // if(test) | |
| 1638 // / | | |
| 1639 // v | | |
| 1640 // proj v | |
| 1641 // other-proj | |
| 1642 // | |
| 1643 // after | |
| 1644 // if(test) | |
| 1645 // / | | |
| 1646 // v | | |
| 1647 // * proj-clone v | |
| 1648 // | other-proj | |
| 1649 // v | |
| 1650 // * new-region | |
| 1651 // | | |
| 1652 // v | |
| 1653 // * dum_if | |
| 1654 // / \ | |
| 1655 // v \ | |
| 1656 // * dum-proj v | |
| 1657 // proj | |
| 1658 // | |
| 1659 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { | |
| 1660 IfNode* iff = proj->in(0)->as_If(); | |
| 1661 IdealLoopTree *loop = get_loop(proj); | |
| 1662 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
| 1663 int ddepth = dom_depth(proj); | |
| 1664 | |
| 1665 _igvn.hash_delete(iff); | |
| 1666 _igvn._worklist.push(iff); | |
| 1667 _igvn.hash_delete(proj); | |
| 1668 _igvn._worklist.push(proj); | |
| 1669 | |
| 1670 proj->set_req(0, NULL); // temporary disconnect | |
| 1671 ProjNode* proj2 = proj_clone(proj, iff); | |
| 1672 register_node(proj2, loop, iff, ddepth); | |
| 1673 | |
| 1674 RegionNode* reg = new (C,2)RegionNode(2); | |
| 1675 reg->set_req(1, proj2); | |
| 1676 register_node(reg, loop, iff, ddepth); | |
| 1677 | |
| 1678 IfNode* dum_if = new (C,2)IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); | |
| 1679 register_node(dum_if, loop, reg, ddepth); | |
| 1680 | |
| 1681 proj->set_req(0, dum_if); // reattach | |
| 1682 set_idom(proj, dum_if, ddepth); | |
| 1683 | |
| 1684 ProjNode* dum_proj = proj_clone(other_proj, dum_if); | |
| 1685 register_node(dum_proj, loop, dum_if, ddepth); | |
| 1686 | |
| 1687 return reg; | |
| 1688 } | |
| 1689 | |
| 1690 //------------------------------ insert_cmpi_loop_exit ------------------------------------- | |
| 1691 // Clone a signed compare loop exit from an unsigned compare and | |
| 1692 // insert it before the unsigned cmp on the stay-in-loop path. | |
| 1693 // All new nodes inserted in the dominator tree between the original | |
| 1694 // if and it's projections. The original if test is replaced with | |
| 1695 // a constant to force the stay-in-loop path. | |
| 1696 // | |
| 1697 // This is done to make sure that the original if and it's projections | |
| 1698 // still dominate the same set of control nodes, that the ctrl() relation | |
| 1699 // from data nodes to them is preserved, and that their loop nesting is | |
| 1700 // preserved. | |
| 1701 // | |
| 1702 // before | |
| 1703 // if(i <u limit) unsigned compare loop exit | |
| 1704 // / | | |
| 1705 // v v | |
| 1706 // exit-proj stay-in-loop-proj | |
| 1707 // | |
| 1708 // after | |
| 1709 // if(stay-in-loop-const) original if | |
| 1710 // / | | |
| 1711 // / v | |
| 1712 // / if(i < limit) new signed test | |
| 1713 // / / | | |
| 1714 // / / v | |
| 1715 // / / if(i <u limit) new cloned unsigned test | |
| 1716 // / / / | | |
| 1717 // v v v | | |
| 1718 // region | | |
| 1719 // | | | |
| 1720 // dum-if | | |
| 1721 // / | | | |
| 1722 // ether | | | |
| 1723 // v v | |
| 1724 // exit-proj stay-in-loop-proj | |
| 1725 // | |
| 1726 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { | |
| 1727 const bool Signed = true; | |
| 1728 const bool Unsigned = false; | |
| 1729 | |
| 1730 BoolNode* bol = if_cmpu->in(1)->as_Bool(); | |
| 1731 if (bol->_test._test != BoolTest::lt) return NULL; | |
| 1732 CmpNode* cmpu = bol->in(1)->as_Cmp(); | |
| 1733 if (cmpu->Opcode() != Op_CmpU) return NULL; | |
| 1734 int stride = stride_of_possible_iv(if_cmpu); | |
| 1735 if (stride == 0) return NULL; | |
| 1736 | |
| 1737 ProjNode* lp_continue = stay_in_loop(if_cmpu, loop)->as_Proj(); | |
| 1738 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); | |
| 1739 | |
| 1740 Node* limit = NULL; | |
| 1741 if (stride > 0) { | |
| 1742 limit = cmpu->in(2); | |
| 1743 } else { | |
| 1744 limit = _igvn.makecon(TypeInt::ZERO); | |
| 1745 set_ctrl(limit, C->root()); | |
| 1746 } | |
| 1747 // Create a new region on the exit path | |
| 1748 RegionNode* reg = insert_region_before_proj(lp_exit); | |
| 1749 | |
| 1750 // Clone the if-cmpu-true-false using a signed compare | |
| 1751 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; | |
| 1752 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); | |
| 1753 reg->add_req(cmpi_exit); | |
| 1754 | |
| 1755 // Clone the if-cmpu-true-false | |
| 1756 BoolTest::mask rel_u = bol->_test._test; | |
| 1757 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); | |
| 1758 reg->add_req(cmpu_exit); | |
| 1759 | |
| 1760 // Force original if to stay in loop. | |
| 1761 short_circuit_if(if_cmpu, lp_continue); | |
| 1762 | |
| 1763 return cmpi_exit->in(0)->as_If(); | |
| 1764 } | |
| 1765 | |
| 1766 //------------------------------ remove_cmpi_loop_exit ------------------------------------- | |
| 1767 // Remove a previously inserted signed compare loop exit. | |
| 1768 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { | |
| 1769 Node* lp_proj = stay_in_loop(if_cmp, loop); | |
| 1770 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && | |
| 1771 stay_in_loop(lp_proj, loop)->is_If() && | |
| 1772 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); | |
| 1773 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); | |
| 1774 set_ctrl(con, C->root()); | |
| 1775 if_cmp->set_req(1, con); | |
| 1776 } | |
| 1777 | |
| 1778 //------------------------------ scheduled_nodelist ------------------------------------- | |
| 1779 // Create a post order schedule of nodes that are in the | |
| 1780 // "member" set. The list is returned in "sched". | |
| 1781 // The first node in "sched" is the loop head, followed by | |
| 1782 // nodes which have no inputs in the "member" set, and then | |
| 1783 // followed by the nodes that have an immediate input dependence | |
| 1784 // on a node in "sched". | |
| 1785 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { | |
| 1786 | |
| 1787 assert(member.test(loop->_head->_idx), "loop head must be in member set"); | |
| 1788 Arena *a = Thread::current()->resource_area(); | |
| 1789 VectorSet visited(a); | |
| 1790 Node_Stack nstack(a, loop->_body.size()); | |
| 1791 | |
| 1792 Node* n = loop->_head; // top of stack is cached in "n" | |
| 1793 uint idx = 0; | |
| 1794 visited.set(n->_idx); | |
| 1795 | |
| 1796 // Initially push all with no inputs from within member set | |
| 1797 for(uint i = 0; i < loop->_body.size(); i++ ) { | |
| 1798 Node *elt = loop->_body.at(i); | |
| 1799 if (member.test(elt->_idx)) { | |
| 1800 bool found = false; | |
| 1801 for (uint j = 0; j < elt->req(); j++) { | |
| 1802 Node* def = elt->in(j); | |
| 1803 if (def && member.test(def->_idx) && def != elt) { | |
| 1804 found = true; | |
| 1805 break; | |
| 1806 } | |
| 1807 } | |
| 1808 if (!found && elt != loop->_head) { | |
| 1809 nstack.push(n, idx); | |
| 1810 n = elt; | |
| 1811 assert(!visited.test(n->_idx), "not seen yet"); | |
| 1812 visited.set(n->_idx); | |
| 1813 } | |
| 1814 } | |
| 1815 } | |
| 1816 | |
| 1817 // traverse out's that are in the member set | |
| 1818 while (true) { | |
| 1819 if (idx < n->outcnt()) { | |
| 1820 Node* use = n->raw_out(idx); | |
| 1821 idx++; | |
| 1822 if (!visited.test_set(use->_idx)) { | |
| 1823 if (member.test(use->_idx)) { | |
| 1824 nstack.push(n, idx); | |
| 1825 n = use; | |
| 1826 idx = 0; | |
| 1827 } | |
| 1828 } | |
| 1829 } else { | |
| 1830 // All outputs processed | |
| 1831 sched.push(n); | |
| 1832 if (nstack.is_empty()) break; | |
| 1833 n = nstack.node(); | |
| 1834 idx = nstack.index(); | |
| 1835 nstack.pop(); | |
| 1836 } | |
| 1837 } | |
| 1838 } | |
| 1839 | |
| 1840 | |
| 1841 //------------------------------ has_use_in_set ------------------------------------- | |
| 1842 // Has a use in the vector set | |
| 1843 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { | |
| 1844 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 1845 Node* use = n->fast_out(j); | |
| 1846 if (vset.test(use->_idx)) { | |
| 1847 return true; | |
| 1848 } | |
| 1849 } | |
| 1850 return false; | |
| 1851 } | |
| 1852 | |
| 1853 | |
| 1854 //------------------------------ has_use_internal_to_set ------------------------------------- | |
| 1855 // Has use internal to the vector set (ie. not in a phi at the loop head) | |
| 1856 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { | |
| 1857 Node* head = loop->_head; | |
| 1858 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 1859 Node* use = n->fast_out(j); | |
| 1860 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { | |
| 1861 return true; | |
| 1862 } | |
| 1863 } | |
| 1864 return false; | |
| 1865 } | |
| 1866 | |
| 1867 | |
| 1868 //------------------------------ clone_for_use_outside_loop ------------------------------------- | |
| 1869 // clone "n" for uses that are outside of loop | |
| 1870 void PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { | |
| 1871 | |
| 1872 assert(worklist.size() == 0, "should be empty"); | |
| 1873 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 1874 Node* use = n->fast_out(j); | |
| 1875 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { | |
| 1876 worklist.push(use); | |
| 1877 } | |
| 1878 } | |
| 1879 while( worklist.size() ) { | |
| 1880 Node *use = worklist.pop(); | |
| 1881 if (!has_node(use) || use->in(0) == C->top()) continue; | |
| 1882 uint j; | |
| 1883 for (j = 0; j < use->req(); j++) { | |
| 1884 if (use->in(j) == n) break; | |
| 1885 } | |
| 1886 assert(j < use->req(), "must be there"); | |
| 1887 | |
| 1888 // clone "n" and insert it between the inputs of "n" and the use outside the loop | |
| 1889 Node* n_clone = n->clone(); | |
| 1890 _igvn.hash_delete(use); | |
| 1891 use->set_req(j, n_clone); | |
| 1892 _igvn._worklist.push(use); | |
| 1893 if (!use->is_Phi()) { | |
| 1894 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); | |
| 1895 set_ctrl(n_clone, use_c); | |
| 1896 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); | |
| 1897 get_loop(use_c)->_body.push(n_clone); | |
| 1898 } else { | |
| 1899 // Use in a phi is considered a use in the associated predecessor block | |
| 1900 Node *prevbb = use->in(0)->in(j); | |
| 1901 set_ctrl(n_clone, prevbb); | |
| 1902 assert(!loop->is_member(get_loop(prevbb)), "should be outside loop"); | |
| 1903 get_loop(prevbb)->_body.push(n_clone); | |
| 1904 } | |
| 1905 _igvn.register_new_node_with_optimizer(n_clone); | |
| 1906 #if !defined(PRODUCT) | |
| 1907 if (TracePartialPeeling) { | |
| 1908 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); | |
| 1909 } | |
| 1910 #endif | |
| 1911 } | |
| 1912 } | |
| 1913 | |
| 1914 | |
| 1915 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- | |
| 1916 // clone "n" for special uses that are in the not_peeled region. | |
| 1917 // If these def-uses occur in separate blocks, the code generator | |
| 1918 // marks the method as not compilable. For example, if a "BoolNode" | |
| 1919 // is in a different basic block than the "IfNode" that uses it, then | |
| 1920 // the compilation is aborted in the code generator. | |
| 1921 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, | |
| 1922 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { | |
| 1923 if (n->is_Phi() || n->is_Load()) { | |
| 1924 return; | |
| 1925 } | |
| 1926 assert(worklist.size() == 0, "should be empty"); | |
| 1927 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 1928 Node* use = n->fast_out(j); | |
| 1929 if ( not_peel.test(use->_idx) && | |
| 1930 (use->is_If() || use->is_CMove() || use->is_Bool()) && | |
| 1931 use->in(1) == n) { | |
| 1932 worklist.push(use); | |
| 1933 } | |
| 1934 } | |
| 1935 if (worklist.size() > 0) { | |
| 1936 // clone "n" and insert it between inputs of "n" and the use | |
| 1937 Node* n_clone = n->clone(); | |
| 1938 loop->_body.push(n_clone); | |
| 1939 _igvn.register_new_node_with_optimizer(n_clone); | |
| 1940 set_ctrl(n_clone, get_ctrl(n)); | |
| 1941 sink_list.push(n_clone); | |
| 1942 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. | |
| 1943 #if !defined(PRODUCT) | |
| 1944 if (TracePartialPeeling) { | |
| 1945 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); | |
| 1946 } | |
| 1947 #endif | |
| 1948 while( worklist.size() ) { | |
| 1949 Node *use = worklist.pop(); | |
| 1950 _igvn.hash_delete(use); | |
| 1951 _igvn._worklist.push(use); | |
| 1952 for (uint j = 1; j < use->req(); j++) { | |
| 1953 if (use->in(j) == n) { | |
| 1954 use->set_req(j, n_clone); | |
| 1955 } | |
| 1956 } | |
| 1957 } | |
| 1958 } | |
| 1959 } | |
| 1960 | |
| 1961 | |
| 1962 //------------------------------ insert_phi_for_loop ------------------------------------- | |
| 1963 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist | |
| 1964 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { | |
| 1965 Node *phi = PhiNode::make(lp, back_edge_val); | |
| 1966 phi->set_req(LoopNode::EntryControl, lp_entry_val); | |
| 1967 // Use existing phi if it already exists | |
| 1968 Node *hit = _igvn.hash_find_insert(phi); | |
| 1969 if( hit == NULL ) { | |
| 1970 _igvn.register_new_node_with_optimizer(phi); | |
| 1971 set_ctrl(phi, lp); | |
| 1972 } else { | |
| 1973 // Remove the new phi from the graph and use the hit | |
| 1974 _igvn.remove_dead_node(phi); | |
| 1975 phi = hit; | |
| 1976 } | |
| 1977 _igvn.hash_delete(use); | |
| 1978 _igvn._worklist.push(use); | |
| 1979 use->set_req(idx, phi); | |
| 1980 } | |
| 1981 | |
| 1982 #ifdef ASSERT | |
| 1983 //------------------------------ is_valid_loop_partition ------------------------------------- | |
| 1984 // Validate the loop partition sets: peel and not_peel | |
| 1985 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, | |
| 1986 VectorSet& not_peel ) { | |
| 1987 uint i; | |
| 1988 // Check that peel_list entries are in the peel set | |
| 1989 for (i = 0; i < peel_list.size(); i++) { | |
| 1990 if (!peel.test(peel_list.at(i)->_idx)) { | |
| 1991 return false; | |
| 1992 } | |
| 1993 } | |
| 1994 // Check at loop members are in one of peel set or not_peel set | |
| 1995 for (i = 0; i < loop->_body.size(); i++ ) { | |
| 1996 Node *def = loop->_body.at(i); | |
| 1997 uint di = def->_idx; | |
| 1998 // Check that peel set elements are in peel_list | |
| 1999 if (peel.test(di)) { | |
| 2000 if (not_peel.test(di)) { | |
| 2001 return false; | |
| 2002 } | |
| 2003 // Must be in peel_list also | |
| 2004 bool found = false; | |
| 2005 for (uint j = 0; j < peel_list.size(); j++) { | |
| 2006 if (peel_list.at(j)->_idx == di) { | |
| 2007 found = true; | |
| 2008 break; | |
| 2009 } | |
| 2010 } | |
| 2011 if (!found) { | |
| 2012 return false; | |
| 2013 } | |
| 2014 } else if (not_peel.test(di)) { | |
| 2015 if (peel.test(di)) { | |
| 2016 return false; | |
| 2017 } | |
| 2018 } else { | |
| 2019 return false; | |
| 2020 } | |
| 2021 } | |
| 2022 return true; | |
| 2023 } | |
| 2024 | |
| 2025 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- | |
| 2026 // Ensure a use outside of loop is of the right form | |
| 2027 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { | |
| 2028 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
| 2029 return (use->is_Phi() && | |
| 2030 use_c->is_Region() && use_c->req() == 3 && | |
| 2031 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || | |
| 2032 use_c->in(exit_idx)->Opcode() == Op_IfFalse || | |
| 2033 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && | |
| 2034 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); | |
| 2035 } | |
| 2036 | |
| 2037 //------------------------------ is_valid_clone_loop_form ------------------------------------- | |
| 2038 // Ensure that all uses outside of loop are of the right form | |
| 2039 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, | |
| 2040 uint orig_exit_idx, uint clone_exit_idx) { | |
| 2041 uint len = peel_list.size(); | |
| 2042 for (uint i = 0; i < len; i++) { | |
| 2043 Node *def = peel_list.at(i); | |
| 2044 | |
| 2045 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
| 2046 Node *use = def->fast_out(j); | |
| 2047 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
| 2048 if (!loop->is_member(get_loop(use_c))) { | |
| 2049 // use is not in the loop, check for correct structure | |
| 2050 if (use->in(0) == def) { | |
| 2051 // Okay | |
| 2052 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { | |
| 2053 return false; | |
| 2054 } | |
| 2055 } | |
| 2056 } | |
| 2057 } | |
| 2058 return true; | |
| 2059 } | |
| 2060 #endif | |
| 2061 | |
| 2062 //------------------------------ partial_peel ------------------------------------- | |
| 2063 // Partially peel (aka loop rotation) the top portion of a loop (called | |
| 2064 // the peel section below) by cloning it and placing one copy just before | |
| 2065 // the new loop head and the other copy at the bottom of the new loop. | |
| 2066 // | |
| 2067 // before after where it came from | |
| 2068 // | |
| 2069 // stmt1 stmt1 | |
| 2070 // loop: stmt2 clone | |
| 2071 // stmt2 if condA goto exitA clone | |
| 2072 // if condA goto exitA new_loop: new | |
| 2073 // stmt3 stmt3 clone | |
| 2074 // if !condB goto loop if condB goto exitB clone | |
| 2075 // exitB: stmt2 orig | |
| 2076 // stmt4 if !condA goto new_loop orig | |
| 2077 // exitA: goto exitA | |
| 2078 // exitB: | |
| 2079 // stmt4 | |
| 2080 // exitA: | |
| 2081 // | |
| 2082 // Step 1: find the cut point: an exit test on probable | |
| 2083 // induction variable. | |
| 2084 // Step 2: schedule (with cloning) operations in the peel | |
| 2085 // section that can be executed after the cut into | |
| 2086 // the section that is not peeled. This may need | |
| 2087 // to clone operations into exit blocks. For | |
| 2088 // instance, a reference to A[i] in the not-peel | |
| 2089 // section and a reference to B[i] in an exit block | |
| 2090 // may cause a left-shift of i by 2 to be placed | |
| 2091 // in the peel block. This step will clone the left | |
| 2092 // shift into the exit block and sink the left shift | |
| 2093 // from the peel to the not-peel section. | |
| 2094 // Step 3: clone the loop, retarget the control, and insert | |
| 2095 // phis for values that are live across the new loop | |
| 2096 // head. This is very dependent on the graph structure | |
| 2097 // from clone_loop. It creates region nodes for | |
| 2098 // exit control and associated phi nodes for values | |
| 2099 // flow out of the loop through that exit. The region | |
| 2100 // node is dominated by the clone's control projection. | |
| 2101 // So the clone's peel section is placed before the | |
| 2102 // new loop head, and the clone's not-peel section is | |
| 2103 // forms the top part of the new loop. The original | |
| 2104 // peel section forms the tail of the new loop. | |
| 2105 // Step 4: update the dominator tree and recompute the | |
| 2106 // dominator depth. | |
| 2107 // | |
| 2108 // orig | |
| 2109 // | |
| 2110 // stmt1 | |
| 2111 // | | |
| 2112 // v | |
| 2113 // loop<----+ | |
| 2114 // | | | |
| 2115 // stmt2 | | |
| 2116 // | | | |
| 2117 // v | | |
| 2118 // ifA | | |
| 2119 // / | | | |
| 2120 // v v | | |
| 2121 // false true ^ <-- last_peel | |
| 2122 // / | | | |
| 2123 // / ===|==cut | | |
| 2124 // / stmt3 | <-- first_not_peel | |
| 2125 // / | | | |
| 2126 // | v | | |
| 2127 // v ifB | | |
| 2128 // exitA: / \ | | |
| 2129 // / \ | | |
| 2130 // v v | | |
| 2131 // false true | | |
| 2132 // / \ | | |
| 2133 // / ----+ | |
| 2134 // | | |
| 2135 // v | |
| 2136 // exitB: | |
| 2137 // stmt4 | |
| 2138 // | |
| 2139 // | |
| 2140 // after clone loop | |
| 2141 // | |
| 2142 // stmt1 | |
| 2143 // / \ | |
| 2144 // clone / \ orig | |
| 2145 // / \ | |
| 2146 // / \ | |
| 2147 // v v | |
| 2148 // +---->loop loop<----+ | |
| 2149 // | | | | | |
| 2150 // | stmt2 stmt2 | | |
| 2151 // | | | | | |
| 2152 // | v v | | |
| 2153 // | ifA ifA | | |
| 2154 // | | \ / | | | |
| 2155 // | v v v v | | |
| 2156 // ^ true false false true ^ <-- last_peel | |
| 2157 // | | ^ \ / | | | |
| 2158 // | cut==|== \ \ / ===|==cut | | |
| 2159 // | stmt3 \ \ / stmt3 | <-- first_not_peel | |
| 2160 // | | dom | | | | | |
| 2161 // | v \ 1v v2 v | | |
| 2162 // | ifB regionA ifB | | |
| 2163 // | / \ | / \ | | |
| 2164 // | / \ v / \ | | |
| 2165 // | v v exitA: v v | | |
| 2166 // | true false false true | | |
| 2167 // | / ^ \ / \ | | |
| 2168 // +---- \ \ / ----+ | |
| 2169 // dom \ / | |
| 2170 // \ 1v v2 | |
| 2171 // regionB | |
| 2172 // | | |
| 2173 // v | |
| 2174 // exitB: | |
| 2175 // stmt4 | |
| 2176 // | |
| 2177 // | |
| 2178 // after partial peel | |
| 2179 // | |
| 2180 // stmt1 | |
| 2181 // / | |
| 2182 // clone / orig | |
| 2183 // / TOP | |
| 2184 // / \ | |
| 2185 // v v | |
| 2186 // TOP->region region----+ | |
| 2187 // | | | | |
| 2188 // stmt2 stmt2 | | |
| 2189 // | | | | |
| 2190 // v v | | |
| 2191 // ifA ifA | | |
| 2192 // | \ / | | | |
| 2193 // v v v v | | |
| 2194 // true false false true | <-- last_peel | |
| 2195 // | ^ \ / +------|---+ | |
| 2196 // +->newloop \ \ / === ==cut | | | |
| 2197 // | stmt3 \ \ / TOP | | | |
| 2198 // | | dom | | stmt3 | | <-- first_not_peel | |
| 2199 // | v \ 1v v2 v | | | |
| 2200 // | ifB regionA ifB ^ v | |
| 2201 // | / \ | / \ | | | |
| 2202 // | / \ v / \ | | | |
| 2203 // | v v exitA: v v | | | |
| 2204 // | true false false true | | | |
| 2205 // | / ^ \ / \ | | | |
| 2206 // | | \ \ / v | | | |
| 2207 // | | dom \ / TOP | | | |
| 2208 // | | \ 1v v2 | | | |
| 2209 // ^ v regionB | | | |
| 2210 // | | | | | | |
| 2211 // | | v ^ v | |
| 2212 // | | exitB: | | | |
| 2213 // | | stmt4 | | | |
| 2214 // | +------------>-----------------+ | | |
| 2215 // | | | |
| 2216 // +-----------------<---------------------+ | |
| 2217 // | |
| 2218 // | |
| 2219 // final graph | |
| 2220 // | |
| 2221 // stmt1 | |
| 2222 // | | |
| 2223 // v | |
| 2224 // ........> ifA clone | |
| 2225 // : / | | |
| 2226 // dom / | | |
| 2227 // : v v | |
| 2228 // : false true | |
| 2229 // : | | | |
| 2230 // : | stmt2 clone | |
| 2231 // : | | | |
| 2232 // : | v | |
| 2233 // : | newloop<-----+ | |
| 2234 // : | | | | |
| 2235 // : | stmt3 clone | | |
| 2236 // : | | | | |
| 2237 // : | v | | |
| 2238 // : | ifB | | |
| 2239 // : | / \ | | |
| 2240 // : | v v | | |
| 2241 // : | false true | | |
| 2242 // : | | | | | |
| 2243 // : | v stmt2 | | |
| 2244 // : | exitB: | | | |
| 2245 // : | stmt4 v | | |
| 2246 // : | ifA orig | | |
| 2247 // : | / \ | | |
| 2248 // : | / \ | | |
| 2249 // : | v v | | |
| 2250 // : | false true | | |
| 2251 // : | / \ | | |
| 2252 // : v v -----+ | |
| 2253 // RegionA | |
| 2254 // | | |
| 2255 // v | |
| 2256 // exitA | |
| 2257 // | |
| 2258 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { | |
| 2259 | |
| 2260 LoopNode *head = loop->_head->as_Loop(); | |
| 2261 | |
| 2262 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { | |
| 2263 return false; | |
| 2264 } | |
| 2265 | |
| 2266 // Check for complex exit control | |
| 2267 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { | |
| 2268 Node *n = loop->_body.at(ii); | |
| 2269 int opc = n->Opcode(); | |
| 2270 if (n->is_Call() || | |
| 2271 opc == Op_Catch || | |
| 2272 opc == Op_CatchProj || | |
| 2273 opc == Op_Jump || | |
| 2274 opc == Op_JumpProj) { | |
| 2275 #if !defined(PRODUCT) | |
| 2276 if (TracePartialPeeling) { | |
| 2277 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); | |
| 2278 } | |
| 2279 #endif | |
| 2280 return false; | |
| 2281 } | |
| 2282 } | |
| 2283 | |
| 2284 int dd = dom_depth(head); | |
| 2285 | |
| 2286 // Step 1: find cut point | |
| 2287 | |
| 2288 // Walk up dominators to loop head looking for first loop exit | |
| 2289 // which is executed on every path thru loop. | |
| 2290 IfNode *peel_if = NULL; | |
| 2291 IfNode *peel_if_cmpu = NULL; | |
| 2292 | |
| 2293 Node *iff = loop->tail(); | |
| 2294 while( iff != head ) { | |
| 2295 if( iff->is_If() ) { | |
| 2296 Node *ctrl = get_ctrl(iff->in(1)); | |
| 2297 if (ctrl->is_top()) return false; // Dead test on live IF. | |
| 2298 // If loop-varying exit-test, check for induction variable | |
| 2299 if( loop->is_member(get_loop(ctrl)) && | |
| 2300 loop->is_loop_exit(iff) && | |
| 2301 is_possible_iv_test(iff)) { | |
| 2302 Node* cmp = iff->in(1)->in(1); | |
| 2303 if (cmp->Opcode() == Op_CmpI) { | |
| 2304 peel_if = iff->as_If(); | |
| 2305 } else { | |
| 2306 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); | |
| 2307 peel_if_cmpu = iff->as_If(); | |
| 2308 } | |
| 2309 } | |
| 2310 } | |
| 2311 iff = idom(iff); | |
| 2312 } | |
| 2313 // Prefer signed compare over unsigned compare. | |
| 2314 IfNode* new_peel_if = NULL; | |
| 2315 if (peel_if == NULL) { | |
| 2316 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { | |
| 2317 return false; // No peel point found | |
| 2318 } | |
| 2319 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); | |
| 2320 if (new_peel_if == NULL) { | |
| 2321 return false; // No peel point found | |
| 2322 } | |
| 2323 peel_if = new_peel_if; | |
| 2324 } | |
| 2325 Node* last_peel = stay_in_loop(peel_if, loop); | |
| 2326 Node* first_not_peeled = stay_in_loop(last_peel, loop); | |
| 2327 if (first_not_peeled == NULL || first_not_peeled == head) { | |
| 2328 return false; | |
| 2329 } | |
| 2330 | |
| 2331 #if !defined(PRODUCT) | |
| 2332 if (TracePartialPeeling) { | |
| 2333 tty->print_cr("before partial peel one iteration"); | |
| 2334 Node_List wl; | |
| 2335 Node* t = head->in(2); | |
| 2336 while (true) { | |
| 2337 wl.push(t); | |
| 2338 if (t == head) break; | |
| 2339 t = idom(t); | |
| 2340 } | |
| 2341 while (wl.size() > 0) { | |
| 2342 Node* tt = wl.pop(); | |
| 2343 tt->dump(); | |
| 2344 if (tt == last_peel) tty->print_cr("-- cut --"); | |
| 2345 } | |
| 2346 } | |
| 2347 #endif | |
| 2348 ResourceArea *area = Thread::current()->resource_area(); | |
| 2349 VectorSet peel(area); | |
| 2350 VectorSet not_peel(area); | |
| 2351 Node_List peel_list(area); | |
| 2352 Node_List worklist(area); | |
| 2353 Node_List sink_list(area); | |
| 2354 | |
| 2355 // Set of cfg nodes to peel are those that are executable from | |
| 2356 // the head through last_peel. | |
| 2357 assert(worklist.size() == 0, "should be empty"); | |
| 2358 worklist.push(head); | |
| 2359 peel.set(head->_idx); | |
| 2360 while (worklist.size() > 0) { | |
| 2361 Node *n = worklist.pop(); | |
| 2362 if (n != last_peel) { | |
| 2363 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
| 2364 Node* use = n->fast_out(j); | |
| 2365 if (use->is_CFG() && | |
| 2366 loop->is_member(get_loop(use)) && | |
| 2367 !peel.test_set(use->_idx)) { | |
| 2368 worklist.push(use); | |
| 2369 } | |
| 2370 } | |
| 2371 } | |
| 2372 } | |
| 2373 | |
| 2374 // Set of non-cfg nodes to peel are those that are control | |
| 2375 // dependent on the cfg nodes. | |
| 2376 uint i; | |
| 2377 for(i = 0; i < loop->_body.size(); i++ ) { | |
| 2378 Node *n = loop->_body.at(i); | |
| 2379 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; | |
| 2380 if (peel.test(n_c->_idx)) { | |
| 2381 peel.set(n->_idx); | |
| 2382 } else { | |
| 2383 not_peel.set(n->_idx); | |
| 2384 } | |
| 2385 } | |
| 2386 | |
| 2387 // Step 2: move operations from the peeled section down into the | |
| 2388 // not-peeled section | |
| 2389 | |
| 2390 // Get a post order schedule of nodes in the peel region | |
| 2391 // Result in right-most operand. | |
| 2392 scheduled_nodelist(loop, peel, peel_list ); | |
| 2393 | |
| 2394 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
| 2395 | |
| 2396 // For future check for too many new phis | |
| 2397 uint old_phi_cnt = 0; | |
| 2398 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { | |
| 2399 Node* use = head->fast_out(j); | |
| 2400 if (use->is_Phi()) old_phi_cnt++; | |
| 2401 } | |
| 2402 | |
| 2403 #if !defined(PRODUCT) | |
| 2404 if (TracePartialPeeling) { | |
| 2405 tty->print_cr("\npeeled list"); | |
| 2406 } | |
| 2407 #endif | |
| 2408 | |
| 2409 // Evacuate nodes in peel region into the not_peeled region if possible | |
| 2410 uint new_phi_cnt = 0; | |
| 2411 for (i = 0; i < peel_list.size();) { | |
| 2412 Node* n = peel_list.at(i); | |
| 2413 #if !defined(PRODUCT) | |
| 2414 if (TracePartialPeeling) n->dump(); | |
| 2415 #endif | |
| 2416 bool incr = true; | |
| 2417 if ( !n->is_CFG() ) { | |
| 2418 | |
| 2419 if ( has_use_in_set(n, not_peel) ) { | |
| 2420 | |
| 2421 // If not used internal to the peeled region, | |
| 2422 // move "n" from peeled to not_peeled region. | |
| 2423 | |
| 2424 if ( !has_use_internal_to_set(n, peel, loop) ) { | |
| 2425 | |
| 2426 // if not pinned and not a load (which maybe anti-dependent on a store) | |
| 2427 // and not a CMove (Matcher expects only bool->cmove). | |
| 2428 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { | |
| 2429 clone_for_use_outside_loop( loop, n, worklist ); | |
| 2430 | |
| 2431 sink_list.push(n); | |
| 2432 peel >>= n->_idx; // delete n from peel set. | |
| 2433 not_peel <<= n->_idx; // add n to not_peel set. | |
| 2434 peel_list.remove(i); | |
| 2435 incr = false; | |
| 2436 #if !defined(PRODUCT) | |
| 2437 if (TracePartialPeeling) { | |
| 2438 tty->print_cr("sink to not_peeled region: %d newbb: %d", | |
| 2439 n->_idx, get_ctrl(n)->_idx); | |
| 2440 } | |
| 2441 #endif | |
| 2442 } | |
| 2443 } else { | |
| 2444 // Otherwise check for special def-use cases that span | |
| 2445 // the peel/not_peel boundary such as bool->if | |
| 2446 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); | |
| 2447 new_phi_cnt++; | |
| 2448 } | |
| 2449 } | |
| 2450 } | |
| 2451 if (incr) i++; | |
| 2452 } | |
| 2453 | |
| 2454 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { | |
| 2455 #if !defined(PRODUCT) | |
| 2456 if (TracePartialPeeling) { | |
| 2457 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", | |
| 2458 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); | |
| 2459 } | |
| 2460 #endif | |
| 2461 if (new_peel_if != NULL) { | |
| 2462 remove_cmpi_loop_exit(new_peel_if, loop); | |
| 2463 } | |
| 2464 // Inhibit more partial peeling on this loop | |
| 2465 assert(!head->is_partial_peel_loop(), "not partial peeled"); | |
| 2466 head->mark_partial_peel_failed(); | |
| 2467 return false; | |
| 2468 } | |
| 2469 | |
| 2470 // Step 3: clone loop, retarget control, and insert new phis | |
| 2471 | |
| 2472 // Create new loop head for new phis and to hang | |
| 2473 // the nodes being moved (sinked) from the peel region. | |
| 2474 LoopNode* new_head = new (C, 3) LoopNode(last_peel, last_peel); | |
| 2475 _igvn.register_new_node_with_optimizer(new_head); | |
| 2476 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); | |
| 2477 first_not_peeled->set_req(0, new_head); | |
| 2478 set_loop(new_head, loop); | |
| 2479 loop->_body.push(new_head); | |
| 2480 not_peel.set(new_head->_idx); | |
| 2481 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); | |
| 2482 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); | |
| 2483 | |
| 2484 while (sink_list.size() > 0) { | |
| 2485 Node* n = sink_list.pop(); | |
| 2486 set_ctrl(n, new_head); | |
| 2487 } | |
| 2488 | |
| 2489 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
| 2490 | |
| 2491 clone_loop( loop, old_new, dd ); | |
| 2492 | |
| 2493 const uint clone_exit_idx = 1; | |
| 2494 const uint orig_exit_idx = 2; | |
| 2495 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); | |
| 2496 | |
| 2497 Node* head_clone = old_new[head->_idx]; | |
| 2498 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); | |
| 2499 Node* orig_tail_clone = head_clone->in(2); | |
| 2500 | |
| 2501 // Add phi if "def" node is in peel set and "use" is not | |
| 2502 | |
| 2503 for(i = 0; i < peel_list.size(); i++ ) { | |
| 2504 Node *def = peel_list.at(i); | |
| 2505 if (!def->is_CFG()) { | |
| 2506 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
| 2507 Node *use = def->fast_out(j); | |
| 2508 if (has_node(use) && use->in(0) != C->top() && | |
| 2509 (!peel.test(use->_idx) || | |
| 2510 (use->is_Phi() && use->in(0) == head)) ) { | |
| 2511 worklist.push(use); | |
| 2512 } | |
| 2513 } | |
| 2514 while( worklist.size() ) { | |
| 2515 Node *use = worklist.pop(); | |
| 2516 for (uint j = 1; j < use->req(); j++) { | |
| 2517 Node* n = use->in(j); | |
| 2518 if (n == def) { | |
| 2519 | |
| 2520 // "def" is in peel set, "use" is not in peel set | |
| 2521 // or "use" is in the entry boundary (a phi) of the peel set | |
| 2522 | |
| 2523 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
| 2524 | |
| 2525 if ( loop->is_member(get_loop( use_c )) ) { | |
| 2526 // use is in loop | |
| 2527 if (old_new[use->_idx] != NULL) { // null for dead code | |
| 2528 Node* use_clone = old_new[use->_idx]; | |
| 2529 _igvn.hash_delete(use); | |
| 2530 use->set_req(j, C->top()); | |
| 2531 _igvn._worklist.push(use); | |
| 2532 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); | |
| 2533 } | |
| 2534 } else { | |
| 2535 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); | |
| 2536 // use is not in the loop, check if the live range includes the cut | |
| 2537 Node* lp_if = use_c->in(orig_exit_idx)->in(0); | |
| 2538 if (not_peel.test(lp_if->_idx)) { | |
| 2539 assert(j == orig_exit_idx, "use from original loop"); | |
| 2540 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); | |
| 2541 } | |
| 2542 } | |
| 2543 } | |
| 2544 } | |
| 2545 } | |
| 2546 } | |
| 2547 } | |
| 2548 | |
| 2549 // Step 3b: retarget control | |
| 2550 | |
| 2551 // Redirect control to the new loop head if a cloned node in | |
| 2552 // the not_peeled region has control that points into the peeled region. | |
| 2553 // This necessary because the cloned peeled region will be outside | |
| 2554 // the loop. | |
| 2555 // from to | |
| 2556 // cloned-peeled <---+ | |
| 2557 // new_head_clone: | <--+ | |
| 2558 // cloned-not_peeled in(0) in(0) | |
| 2559 // orig-peeled | |
| 2560 | |
| 2561 for(i = 0; i < loop->_body.size(); i++ ) { | |
| 2562 Node *n = loop->_body.at(i); | |
| 2563 if (!n->is_CFG() && n->in(0) != NULL && | |
| 2564 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { | |
| 2565 Node* n_clone = old_new[n->_idx]; | |
| 2566 _igvn.hash_delete(n_clone); | |
| 2567 n_clone->set_req(0, new_head_clone); | |
| 2568 _igvn._worklist.push(n_clone); | |
| 2569 } | |
| 2570 } | |
| 2571 | |
| 2572 // Backedge of the surviving new_head (the clone) is original last_peel | |
| 2573 _igvn.hash_delete(new_head_clone); | |
| 2574 new_head_clone->set_req(LoopNode::LoopBackControl, last_peel); | |
| 2575 _igvn._worklist.push(new_head_clone); | |
| 2576 | |
| 2577 // Cut first node in original not_peel set | |
| 2578 _igvn.hash_delete(new_head); | |
| 2579 new_head->set_req(LoopNode::EntryControl, C->top()); | |
| 2580 new_head->set_req(LoopNode::LoopBackControl, C->top()); | |
| 2581 _igvn._worklist.push(new_head); | |
| 2582 | |
| 2583 // Copy head_clone back-branch info to original head | |
| 2584 // and remove original head's loop entry and | |
| 2585 // clone head's back-branch | |
| 2586 _igvn.hash_delete(head); | |
| 2587 _igvn.hash_delete(head_clone); | |
| 2588 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); | |
| 2589 head->set_req(LoopNode::LoopBackControl, C->top()); | |
| 2590 head_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
| 2591 _igvn._worklist.push(head); | |
| 2592 _igvn._worklist.push(head_clone); | |
| 2593 | |
| 2594 // Similarly modify the phis | |
| 2595 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { | |
| 2596 Node* use = head->fast_out(k); | |
| 2597 if (use->is_Phi() && use->outcnt() > 0) { | |
| 2598 Node* use_clone = old_new[use->_idx]; | |
| 2599 _igvn.hash_delete(use); | |
| 2600 _igvn.hash_delete(use_clone); | |
| 2601 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); | |
| 2602 use->set_req(LoopNode::LoopBackControl, C->top()); | |
| 2603 use_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
| 2604 _igvn._worklist.push(use); | |
| 2605 _igvn._worklist.push(use_clone); | |
| 2606 } | |
| 2607 } | |
| 2608 | |
| 2609 // Step 4: update dominator tree and dominator depth | |
| 2610 | |
| 2611 set_idom(head, orig_tail_clone, dd); | |
| 2612 recompute_dom_depth(); | |
| 2613 | |
| 2614 // Inhibit more partial peeling on this loop | |
| 2615 new_head_clone->set_partial_peel_loop(); | |
| 2616 C->set_major_progress(); | |
| 2617 | |
| 2618 #if !defined(PRODUCT) | |
| 2619 if (TracePartialPeeling) { | |
| 2620 tty->print_cr("\nafter partial peel one iteration"); | |
| 2621 Node_List wl(area); | |
| 2622 Node* t = last_peel; | |
| 2623 while (true) { | |
| 2624 wl.push(t); | |
| 2625 if (t == head_clone) break; | |
| 2626 t = idom(t); | |
| 2627 } | |
| 2628 while (wl.size() > 0) { | |
| 2629 Node* tt = wl.pop(); | |
| 2630 if (tt == head) tty->print_cr("orig head"); | |
| 2631 else if (tt == new_head_clone) tty->print_cr("new head"); | |
| 2632 else if (tt == head_clone) tty->print_cr("clone head"); | |
| 2633 tt->dump(); | |
| 2634 } | |
| 2635 } | |
| 2636 #endif | |
| 2637 return true; | |
| 2638 } | |
| 2639 | |
| 2640 //------------------------------reorg_offsets---------------------------------- | |
| 2641 // Reorganize offset computations to lower register pressure. Mostly | |
| 2642 // prevent loop-fallout uses of the pre-incremented trip counter (which are | |
| 2643 // then alive with the post-incremented trip counter forcing an extra | |
| 2644 // register move) | |
| 2645 void PhaseIdealLoop::reorg_offsets( IdealLoopTree *loop ) { | |
| 2646 | |
| 2647 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
| 2648 CountedLoopEndNode *cle = cl->loopexit(); | |
| 2649 if( !cle ) return; // The occasional dead loop | |
| 2650 // Find loop exit control | |
| 2651 Node *exit = cle->proj_out(false); | |
| 2652 assert( exit->Opcode() == Op_IfFalse, "" ); | |
| 2653 | |
| 2654 // Check for the special case of folks using the pre-incremented | |
| 2655 // trip-counter on the fall-out path (forces the pre-incremented | |
| 2656 // and post-incremented trip counter to be live at the same time). | |
| 2657 // Fix this by adjusting to use the post-increment trip counter. | |
| 2658 Node *phi = cl->phi(); | |
| 2659 if( !phi ) return; // Dead infinite loop | |
| 2660 bool progress = true; | |
| 2661 while (progress) { | |
| 2662 progress = false; | |
| 2663 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { | |
| 2664 Node* use = phi->fast_out(i); // User of trip-counter | |
| 2665 if (!has_ctrl(use)) continue; | |
| 2666 Node *u_ctrl = get_ctrl(use); | |
| 2667 if( use->is_Phi() ) { | |
| 2668 u_ctrl = NULL; | |
| 2669 for( uint j = 1; j < use->req(); j++ ) | |
| 2670 if( use->in(j) == phi ) | |
| 2671 u_ctrl = dom_lca( u_ctrl, use->in(0)->in(j) ); | |
| 2672 } | |
| 2673 IdealLoopTree *u_loop = get_loop(u_ctrl); | |
| 2674 // Look for loop-invariant use | |
| 2675 if( u_loop == loop ) continue; | |
| 2676 if( loop->is_member( u_loop ) ) continue; | |
| 2677 // Check that use is live out the bottom. Assuming the trip-counter | |
| 2678 // update is right at the bottom, uses of of the loop middle are ok. | |
| 2679 if( dom_lca( exit, u_ctrl ) != exit ) continue; | |
| 2680 // protect against stride not being a constant | |
| 2681 if( !cle->stride_is_con() ) continue; | |
| 2682 // Hit! Refactor use to use the post-incremented tripcounter. | |
| 2683 // Compute a post-increment tripcounter. | |
| 2684 Node *opaq = new (C, 2) Opaque2Node( cle->incr() ); | |
| 2685 register_new_node( opaq, u_ctrl ); | |
| 2686 Node *neg_stride = _igvn.intcon(-cle->stride_con()); | |
| 2687 set_ctrl(neg_stride, C->root()); | |
| 2688 Node *post = new (C, 3) AddINode( opaq, neg_stride); | |
| 2689 register_new_node( post, u_ctrl ); | |
| 2690 _igvn.hash_delete(use); | |
| 2691 _igvn._worklist.push(use); | |
| 2692 for( uint j = 1; j < use->req(); j++ ) | |
| 2693 if( use->in(j) == phi ) | |
| 2694 use->set_req(j, post); | |
| 2695 // Since DU info changed, rerun loop | |
| 2696 progress = true; | |
| 2697 break; | |
| 2698 } | |
| 2699 } | |
| 2700 | |
| 2701 } |