1 /* 2 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "incls/_precompiled.incl" 26 #include "incls/_ifg.cpp.incl" 27 28 #define EXACT_PRESSURE 1 29 30 //============================================================================= 31 //------------------------------IFG-------------------------------------------- 32 PhaseIFG::PhaseIFG( Arena *arena ) : Phase(Interference_Graph), _arena(arena) { 33 } 34 35 //------------------------------init------------------------------------------- 36 void PhaseIFG::init( uint maxlrg ) { 37 _maxlrg = maxlrg; 38 _yanked = new (_arena) VectorSet(_arena); 39 _is_square = false; 40 // Make uninitialized adjacency lists 41 _adjs = (IndexSet*)_arena->Amalloc(sizeof(IndexSet)*maxlrg); 42 // Also make empty live range structures 43 _lrgs = (LRG *)_arena->Amalloc( maxlrg * sizeof(LRG) ); 44 memset(_lrgs,0,sizeof(LRG)*maxlrg); 45 // Init all to empty 46 for( uint i = 0; i < maxlrg; i++ ) { 47 _adjs[i].initialize(maxlrg); 48 _lrgs[i].Set_All(); 49 } 50 } 51 52 //------------------------------add-------------------------------------------- 53 // Add edge between vertices a & b. These are sorted (triangular matrix), 54 // then the smaller number is inserted in the larger numbered array. 55 int PhaseIFG::add_edge( uint a, uint b ) { 56 lrgs(a).invalid_degree(); 57 lrgs(b).invalid_degree(); 58 // Sort a and b, so that a is bigger 59 assert( !_is_square, "only on triangular" ); 60 if( a < b ) { uint tmp = a; a = b; b = tmp; } 61 return _adjs[a].insert( b ); 62 } 63 64 //------------------------------add_vector------------------------------------- 65 // Add an edge between 'a' and everything in the vector. 66 void PhaseIFG::add_vector( uint a, IndexSet *vec ) { 67 // IFG is triangular, so do the inserts where 'a' < 'b'. 68 assert( !_is_square, "only on triangular" ); 69 IndexSet *adjs_a = &_adjs[a]; 70 if( !vec->count() ) return; 71 72 IndexSetIterator elements(vec); 73 uint neighbor; 74 while ((neighbor = elements.next()) != 0) { 75 add_edge( a, neighbor ); 76 } 77 } 78 79 //------------------------------test------------------------------------------- 80 // Is there an edge between a and b? 81 int PhaseIFG::test_edge( uint a, uint b ) const { 82 // Sort a and b, so that a is larger 83 assert( !_is_square, "only on triangular" ); 84 if( a < b ) { uint tmp = a; a = b; b = tmp; } 85 return _adjs[a].member(b); 86 } 87 88 //------------------------------SquareUp--------------------------------------- 89 // Convert triangular matrix to square matrix 90 void PhaseIFG::SquareUp() { 91 assert( !_is_square, "only on triangular" ); 92 93 // Simple transpose 94 for( uint i = 0; i < _maxlrg; i++ ) { 95 IndexSetIterator elements(&_adjs[i]); 96 uint datum; 97 while ((datum = elements.next()) != 0) { 98 _adjs[datum].insert( i ); 99 } 100 } 101 _is_square = true; 102 } 103 104 //------------------------------Compute_Effective_Degree----------------------- 105 // Compute effective degree in bulk 106 void PhaseIFG::Compute_Effective_Degree() { 107 assert( _is_square, "only on square" ); 108 109 for( uint i = 0; i < _maxlrg; i++ ) 110 lrgs(i).set_degree(effective_degree(i)); 111 } 112 113 //------------------------------test_edge_sq----------------------------------- 114 int PhaseIFG::test_edge_sq( uint a, uint b ) const { 115 assert( _is_square, "only on square" ); 116 // Swap, so that 'a' has the lesser count. Then binary search is on 117 // the smaller of a's list and b's list. 118 if( neighbor_cnt(a) > neighbor_cnt(b) ) { uint tmp = a; a = b; b = tmp; } 119 //return _adjs[a].unordered_member(b); 120 return _adjs[a].member(b); 121 } 122 123 //------------------------------Union------------------------------------------ 124 // Union edges of B into A 125 void PhaseIFG::Union( uint a, uint b ) { 126 assert( _is_square, "only on square" ); 127 IndexSet *A = &_adjs[a]; 128 IndexSetIterator b_elements(&_adjs[b]); 129 uint datum; 130 while ((datum = b_elements.next()) != 0) { 131 if(A->insert(datum)) { 132 _adjs[datum].insert(a); 133 lrgs(a).invalid_degree(); 134 lrgs(datum).invalid_degree(); 135 } 136 } 137 } 138 139 //------------------------------remove_node------------------------------------ 140 // Yank a Node and all connected edges from the IFG. Return a 141 // list of neighbors (edges) yanked. 142 IndexSet *PhaseIFG::remove_node( uint a ) { 143 assert( _is_square, "only on square" ); 144 assert( !_yanked->test(a), "" ); 145 _yanked->set(a); 146 147 // I remove the LRG from all neighbors. 148 IndexSetIterator elements(&_adjs[a]); 149 LRG &lrg_a = lrgs(a); 150 uint datum; 151 while ((datum = elements.next()) != 0) { 152 _adjs[datum].remove(a); 153 lrgs(datum).inc_degree( -lrg_a.compute_degree(lrgs(datum)) ); 154 } 155 return neighbors(a); 156 } 157 158 //------------------------------re_insert-------------------------------------- 159 // Re-insert a yanked Node. 160 void PhaseIFG::re_insert( uint a ) { 161 assert( _is_square, "only on square" ); 162 assert( _yanked->test(a), "" ); 163 (*_yanked) >>= a; 164 165 IndexSetIterator elements(&_adjs[a]); 166 uint datum; 167 while ((datum = elements.next()) != 0) { 168 _adjs[datum].insert(a); 169 lrgs(datum).invalid_degree(); 170 } 171 } 172 173 //------------------------------compute_degree--------------------------------- 174 // Compute the degree between 2 live ranges. If both live ranges are 175 // aligned-adjacent powers-of-2 then we use the MAX size. If either is 176 // mis-aligned (or for Fat-Projections, not-adjacent) then we have to 177 // MULTIPLY the sizes. Inspect Brigg's thesis on register pairs to see why 178 // this is so. 179 int LRG::compute_degree( LRG &l ) const { 180 int tmp; 181 int num_regs = _num_regs; 182 int nregs = l.num_regs(); 183 tmp = (_fat_proj || l._fat_proj) // either is a fat-proj? 184 ? (num_regs * nregs) // then use product 185 : MAX2(num_regs,nregs); // else use max 186 return tmp; 187 } 188 189 //------------------------------effective_degree------------------------------- 190 // Compute effective degree for this live range. If both live ranges are 191 // aligned-adjacent powers-of-2 then we use the MAX size. If either is 192 // mis-aligned (or for Fat-Projections, not-adjacent) then we have to 193 // MULTIPLY the sizes. Inspect Brigg's thesis on register pairs to see why 194 // this is so. 195 int PhaseIFG::effective_degree( uint lidx ) const { 196 int eff = 0; 197 int num_regs = lrgs(lidx).num_regs(); 198 int fat_proj = lrgs(lidx)._fat_proj; 199 IndexSet *s = neighbors(lidx); 200 IndexSetIterator elements(s); 201 uint nidx; 202 while((nidx = elements.next()) != 0) { 203 LRG &lrgn = lrgs(nidx); 204 int nregs = lrgn.num_regs(); 205 eff += (fat_proj || lrgn._fat_proj) // either is a fat-proj? 206 ? (num_regs * nregs) // then use product 207 : MAX2(num_regs,nregs); // else use max 208 } 209 return eff; 210 } 211 212 213 #ifndef PRODUCT 214 //------------------------------dump------------------------------------------- 215 void PhaseIFG::dump() const { 216 tty->print_cr("-- Interference Graph --%s--", 217 _is_square ? "square" : "triangular" ); 218 if( _is_square ) { 219 for( uint i = 0; i < _maxlrg; i++ ) { 220 tty->print( (*_yanked)[i] ? "XX " : " "); 221 tty->print("L%d: { ",i); 222 IndexSetIterator elements(&_adjs[i]); 223 uint datum; 224 while ((datum = elements.next()) != 0) { 225 tty->print("L%d ", datum); 226 } 227 tty->print_cr("}"); 228 229 } 230 return; 231 } 232 233 // Triangular 234 for( uint i = 0; i < _maxlrg; i++ ) { 235 uint j; 236 tty->print( (*_yanked)[i] ? "XX " : " "); 237 tty->print("L%d: { ",i); 238 for( j = _maxlrg; j > i; j-- ) 239 if( test_edge(j - 1,i) ) { 240 tty->print("L%d ",j - 1); 241 } 242 tty->print("| "); 243 IndexSetIterator elements(&_adjs[i]); 244 uint datum; 245 while ((datum = elements.next()) != 0) { 246 tty->print("L%d ", datum); 247 } 248 tty->print("}\n"); 249 } 250 tty->print("\n"); 251 } 252 253 //------------------------------stats------------------------------------------ 254 void PhaseIFG::stats() const { 255 ResourceMark rm; 256 int *h_cnt = NEW_RESOURCE_ARRAY(int,_maxlrg*2); 257 memset( h_cnt, 0, sizeof(int)*_maxlrg*2 ); 258 uint i; 259 for( i = 0; i < _maxlrg; i++ ) { 260 h_cnt[neighbor_cnt(i)]++; 261 } 262 tty->print_cr("--Histogram of counts--"); 263 for( i = 0; i < _maxlrg*2; i++ ) 264 if( h_cnt[i] ) 265 tty->print("%d/%d ",i,h_cnt[i]); 266 tty->print_cr(""); 267 } 268 269 //------------------------------verify----------------------------------------- 270 void PhaseIFG::verify( const PhaseChaitin *pc ) const { 271 // IFG is square, sorted and no need for Find 272 for( uint i = 0; i < _maxlrg; i++ ) { 273 assert(!((*_yanked)[i]) || !neighbor_cnt(i), "Is removed completely" ); 274 IndexSet *set = &_adjs[i]; 275 IndexSetIterator elements(set); 276 uint idx; 277 uint last = 0; 278 while ((idx = elements.next()) != 0) { 279 assert( idx != i, "Must have empty diagonal"); 280 assert( pc->Find_const(idx) == idx, "Must not need Find" ); 281 assert( _adjs[idx].member(i), "IFG not square" ); 282 assert( !(*_yanked)[idx], "No yanked neighbors" ); 283 assert( last < idx, "not sorted increasing"); 284 last = idx; 285 } 286 assert( !lrgs(i)._degree_valid || 287 effective_degree(i) == lrgs(i).degree(), "degree is valid but wrong" ); 288 } 289 } 290 #endif 291 292 //------------------------------interfere_with_live---------------------------- 293 // Interfere this register with everything currently live. Use the RegMasks 294 // to trim the set of possible interferences. Return a count of register-only 295 // interferences as an estimate of register pressure. 296 void PhaseChaitin::interfere_with_live( uint r, IndexSet *liveout ) { 297 uint retval = 0; 298 // Interfere with everything live. 299 const RegMask &rm = lrgs(r).mask(); 300 // Check for interference by checking overlap of regmasks. 301 // Only interfere if acceptable register masks overlap. 302 IndexSetIterator elements(liveout); 303 uint l; 304 while( (l = elements.next()) != 0 ) 305 if( rm.overlap( lrgs(l).mask() ) ) 306 _ifg->add_edge( r, l ); 307 } 308 309 //------------------------------build_ifg_virtual------------------------------ 310 // Actually build the interference graph. Uses virtual registers only, no 311 // physical register masks. This allows me to be very aggressive when 312 // coalescing copies. Some of this aggressiveness will have to be undone 313 // later, but I'd rather get all the copies I can now (since unremoved copies 314 // at this point can end up in bad places). Copies I re-insert later I have 315 // more opportunity to insert them in low-frequency locations. 316 void PhaseChaitin::build_ifg_virtual( ) { 317 318 // For all blocks (in any order) do... 319 for( uint i=0; i<_cfg._num_blocks; i++ ) { 320 Block *b = _cfg._blocks[i]; 321 IndexSet *liveout = _live->live(b); 322 323 // The IFG is built by a single reverse pass over each basic block. 324 // Starting with the known live-out set, we remove things that get 325 // defined and add things that become live (essentially executing one 326 // pass of a standard LIVE analysis). Just before a Node defines a value 327 // (and removes it from the live-ness set) that value is certainly live. 328 // The defined value interferes with everything currently live. The 329 // value is then removed from the live-ness set and it's inputs are 330 // added to the live-ness set. 331 for( uint j = b->end_idx() + 1; j > 1; j-- ) { 332 Node *n = b->_nodes[j-1]; 333 334 // Get value being defined 335 uint r = n2lidx(n); 336 337 // Some special values do not allocate 338 if( r ) { 339 340 // Remove from live-out set 341 liveout->remove(r); 342 343 // Copies do not define a new value and so do not interfere. 344 // Remove the copies source from the liveout set before interfering. 345 uint idx = n->is_Copy(); 346 if( idx ) liveout->remove( n2lidx(n->in(idx)) ); 347 348 // Interfere with everything live 349 interfere_with_live( r, liveout ); 350 } 351 352 // Make all inputs live 353 if( !n->is_Phi() ) { // Phi function uses come from prior block 354 for( uint k = 1; k < n->req(); k++ ) 355 liveout->insert( n2lidx(n->in(k)) ); 356 } 357 358 // 2-address instructions always have the defined value live 359 // on entry to the instruction, even though it is being defined 360 // by the instruction. We pretend a virtual copy sits just prior 361 // to the instruction and kills the src-def'd register. 362 // In other words, for 2-address instructions the defined value 363 // interferes with all inputs. 364 uint idx; 365 if( n->is_Mach() && (idx = n->as_Mach()->two_adr()) ) { 366 const MachNode *mach = n->as_Mach(); 367 // Sometimes my 2-address ADDs are commuted in a bad way. 368 // We generally want the USE-DEF register to refer to the 369 // loop-varying quantity, to avoid a copy. 370 uint op = mach->ideal_Opcode(); 371 // Check that mach->num_opnds() == 3 to ensure instruction is 372 // not subsuming constants, effectively excludes addI_cin_imm 373 // Can NOT swap for instructions like addI_cin_imm since it 374 // is adding zero to yhi + carry and the second ideal-input 375 // points to the result of adding low-halves. 376 // Checking req() and num_opnds() does NOT distinguish addI_cout from addI_cout_imm 377 if( (op == Op_AddI && mach->req() == 3 && mach->num_opnds() == 3) && 378 n->in(1)->bottom_type()->base() == Type::Int && 379 // See if the ADD is involved in a tight data loop the wrong way 380 n->in(2)->is_Phi() && 381 n->in(2)->in(2) == n ) { 382 Node *tmp = n->in(1); 383 n->set_req( 1, n->in(2) ); 384 n->set_req( 2, tmp ); 385 } 386 // Defined value interferes with all inputs 387 uint lidx = n2lidx(n->in(idx)); 388 for( uint k = 1; k < n->req(); k++ ) { 389 uint kidx = n2lidx(n->in(k)); 390 if( kidx != lidx ) 391 _ifg->add_edge( r, kidx ); 392 } 393 } 394 } // End of forall instructions in block 395 } // End of forall blocks 396 } 397 398 //------------------------------count_int_pressure----------------------------- 399 uint PhaseChaitin::count_int_pressure( IndexSet *liveout ) { 400 IndexSetIterator elements(liveout); 401 uint lidx; 402 uint cnt = 0; 403 while ((lidx = elements.next()) != 0) { 404 if( lrgs(lidx).mask().is_UP() && 405 lrgs(lidx).mask_size() && 406 !lrgs(lidx)._is_float && 407 lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) 408 cnt += lrgs(lidx).reg_pressure(); 409 } 410 return cnt; 411 } 412 413 //------------------------------count_float_pressure--------------------------- 414 uint PhaseChaitin::count_float_pressure( IndexSet *liveout ) { 415 IndexSetIterator elements(liveout); 416 uint lidx; 417 uint cnt = 0; 418 while ((lidx = elements.next()) != 0) { 419 if( lrgs(lidx).mask().is_UP() && 420 lrgs(lidx).mask_size() && 421 lrgs(lidx)._is_float ) 422 cnt += lrgs(lidx).reg_pressure(); 423 } 424 return cnt; 425 } 426 427 //------------------------------lower_pressure--------------------------------- 428 // Adjust register pressure down by 1. Capture last hi-to-low transition, 429 static void lower_pressure( LRG *lrg, uint where, Block *b, uint *pressure, uint *hrp_index ) { 430 if( lrg->mask().is_UP() && lrg->mask_size() ) { 431 if( lrg->_is_float ) { 432 pressure[1] -= lrg->reg_pressure(); 433 if( pressure[1] == (uint)FLOATPRESSURE ) { 434 hrp_index[1] = where; 435 #ifdef EXACT_PRESSURE 436 if( pressure[1] > b->_freg_pressure ) 437 b->_freg_pressure = pressure[1]+1; 438 #else 439 b->_freg_pressure = (uint)FLOATPRESSURE+1; 440 #endif 441 } 442 } else if( lrg->mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) { 443 pressure[0] -= lrg->reg_pressure(); 444 if( pressure[0] == (uint)INTPRESSURE ) { 445 hrp_index[0] = where; 446 #ifdef EXACT_PRESSURE 447 if( pressure[0] > b->_reg_pressure ) 448 b->_reg_pressure = pressure[0]+1; 449 #else 450 b->_reg_pressure = (uint)INTPRESSURE+1; 451 #endif 452 } 453 } 454 } 455 } 456 457 //------------------------------build_ifg_physical----------------------------- 458 // Build the interference graph using physical registers when available. 459 // That is, if 2 live ranges are simultaneously alive but in their acceptable 460 // register sets do not overlap, then they do not interfere. 461 uint PhaseChaitin::build_ifg_physical( ResourceArea *a ) { 462 NOT_PRODUCT( Compile::TracePhase t3("buildIFG", &_t_buildIFGphysical, TimeCompiler); ) 463 464 uint spill_reg = LRG::SPILL_REG; 465 uint must_spill = 0; 466 467 // For all blocks (in any order) do... 468 for( uint i = 0; i < _cfg._num_blocks; i++ ) { 469 Block *b = _cfg._blocks[i]; 470 // Clone (rather than smash in place) the liveout info, so it is alive 471 // for the "collect_gc_info" phase later. 472 IndexSet liveout(_live->live(b)); 473 uint last_inst = b->end_idx(); 474 // Compute first nonphi node index 475 uint first_inst; 476 for( first_inst = 1; first_inst < last_inst; first_inst++ ) 477 if( !b->_nodes[first_inst]->is_Phi() ) 478 break; 479 480 // Spills could be inserted before CreateEx node which should be 481 // first instruction in block after Phis. Move CreateEx up. 482 for( uint insidx = first_inst; insidx < last_inst; insidx++ ) { 483 Node *ex = b->_nodes[insidx]; 484 if( ex->is_SpillCopy() ) continue; 485 if( insidx > first_inst && ex->is_Mach() && 486 ex->as_Mach()->ideal_Opcode() == Op_CreateEx ) { 487 // If the CreateEx isn't above all the MachSpillCopies 488 // then move it to the top. 489 b->_nodes.remove(insidx); 490 b->_nodes.insert(first_inst, ex); 491 } 492 // Stop once a CreateEx or any other node is found 493 break; 494 } 495 496 // Reset block's register pressure values for each ifg construction 497 uint pressure[2], hrp_index[2]; 498 pressure[0] = pressure[1] = 0; 499 hrp_index[0] = hrp_index[1] = last_inst+1; 500 b->_reg_pressure = b->_freg_pressure = 0; 501 // Liveout things are presumed live for the whole block. We accumulate 502 // 'area' accordingly. If they get killed in the block, we'll subtract 503 // the unused part of the block from the area. 504 int inst_count = last_inst - first_inst; 505 double cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count); 506 assert(!(cost < 0.0), "negative spill cost" ); 507 IndexSetIterator elements(&liveout); 508 uint lidx; 509 while ((lidx = elements.next()) != 0) { 510 LRG &lrg = lrgs(lidx); 511 lrg._area += cost; 512 // Compute initial register pressure 513 if( lrg.mask().is_UP() && lrg.mask_size() ) { 514 if( lrg._is_float ) { // Count float pressure 515 pressure[1] += lrg.reg_pressure(); 516 #ifdef EXACT_PRESSURE 517 if( pressure[1] > b->_freg_pressure ) 518 b->_freg_pressure = pressure[1]; 519 #endif 520 // Count int pressure, but do not count the SP, flags 521 } else if( lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) { 522 pressure[0] += lrg.reg_pressure(); 523 #ifdef EXACT_PRESSURE 524 if( pressure[0] > b->_reg_pressure ) 525 b->_reg_pressure = pressure[0]; 526 #endif 527 } 528 } 529 } 530 assert( pressure[0] == count_int_pressure (&liveout), "" ); 531 assert( pressure[1] == count_float_pressure(&liveout), "" ); 532 533 // The IFG is built by a single reverse pass over each basic block. 534 // Starting with the known live-out set, we remove things that get 535 // defined and add things that become live (essentially executing one 536 // pass of a standard LIVE analysis). Just before a Node defines a value 537 // (and removes it from the live-ness set) that value is certainly live. 538 // The defined value interferes with everything currently live. The 539 // value is then removed from the live-ness set and it's inputs are added 540 // to the live-ness set. 541 uint j; 542 for( j = last_inst + 1; j > 1; j-- ) { 543 Node *n = b->_nodes[j - 1]; 544 545 // Get value being defined 546 uint r = n2lidx(n); 547 548 // Some special values do not allocate 549 if( r ) { 550 // A DEF normally costs block frequency; rematerialized values are 551 // removed from the DEF sight, so LOWER costs here. 552 lrgs(r)._cost += n->rematerialize() ? 0 : b->_freq; 553 554 // If it is not live, then this instruction is dead. Probably caused 555 // by spilling and rematerialization. Who cares why, yank this baby. 556 if( !liveout.member(r) && n->Opcode() != Op_SafePoint ) { 557 Node *def = n->in(0); 558 if( !n->is_Proj() || 559 // Could also be a flags-projection of a dead ADD or such. 560 (n2lidx(def) && !liveout.member(n2lidx(def)) ) ) { 561 b->_nodes.remove(j - 1); 562 if( lrgs(r)._def == n ) lrgs(r)._def = 0; 563 n->disconnect_inputs(NULL); 564 _cfg._bbs.map(n->_idx,NULL); 565 n->replace_by(C->top()); 566 // Since yanking a Node from block, high pressure moves up one 567 hrp_index[0]--; 568 hrp_index[1]--; 569 continue; 570 } 571 572 // Fat-projections kill many registers which cannot be used to 573 // hold live ranges. 574 if( lrgs(r)._fat_proj ) { 575 // Count the int-only registers 576 RegMask itmp = lrgs(r).mask(); 577 itmp.AND(*Matcher::idealreg2regmask[Op_RegI]); 578 int iregs = itmp.Size(); 579 #ifdef EXACT_PRESSURE 580 if( pressure[0]+iregs > b->_reg_pressure ) 581 b->_reg_pressure = pressure[0]+iregs; 582 #endif 583 if( pressure[0] <= (uint)INTPRESSURE && 584 pressure[0]+iregs > (uint)INTPRESSURE ) { 585 #ifndef EXACT_PRESSURE 586 b->_reg_pressure = (uint)INTPRESSURE+1; 587 #endif 588 hrp_index[0] = j-1; 589 } 590 // Count the float-only registers 591 RegMask ftmp = lrgs(r).mask(); 592 ftmp.AND(*Matcher::idealreg2regmask[Op_RegD]); 593 int fregs = ftmp.Size(); 594 #ifdef EXACT_PRESSURE 595 if( pressure[1]+fregs > b->_freg_pressure ) 596 b->_freg_pressure = pressure[1]+fregs; 597 #endif 598 if( pressure[1] <= (uint)FLOATPRESSURE && 599 pressure[1]+fregs > (uint)FLOATPRESSURE ) { 600 #ifndef EXACT_PRESSURE 601 b->_freg_pressure = (uint)FLOATPRESSURE+1; 602 #endif 603 hrp_index[1] = j-1; 604 } 605 } 606 607 } else { // Else it is live 608 // A DEF also ends 'area' partway through the block. 609 lrgs(r)._area -= cost; 610 assert(!(lrgs(r)._area < 0.0), "negative spill area" ); 611 612 // Insure high score for immediate-use spill copies so they get a color 613 if( n->is_SpillCopy() 614 && lrgs(r).is_singledef() // MultiDef live range can still split 615 && n->outcnt() == 1 // and use must be in this block 616 && _cfg._bbs[n->unique_out()->_idx] == b ) { 617 // All single-use MachSpillCopy(s) that immediately precede their 618 // use must color early. If a longer live range steals their 619 // color, the spill copy will split and may push another spill copy 620 // further away resulting in an infinite spill-split-retry cycle. 621 // Assigning a zero area results in a high score() and a good 622 // location in the simplify list. 623 // 624 625 Node *single_use = n->unique_out(); 626 assert( b->find_node(single_use) >= j, "Use must be later in block"); 627 // Use can be earlier in block if it is a Phi, but then I should be a MultiDef 628 629 // Find first non SpillCopy 'm' that follows the current instruction 630 // (j - 1) is index for current instruction 'n' 631 Node *m = n; 632 for( uint i = j; i <= last_inst && m->is_SpillCopy(); ++i ) { m = b->_nodes[i]; } 633 if( m == single_use ) { 634 lrgs(r)._area = 0.0; 635 } 636 } 637 638 // Remove from live-out set 639 if( liveout.remove(r) ) { 640 // Adjust register pressure. 641 // Capture last hi-to-lo pressure transition 642 lower_pressure( &lrgs(r), j-1, b, pressure, hrp_index ); 643 assert( pressure[0] == count_int_pressure (&liveout), "" ); 644 assert( pressure[1] == count_float_pressure(&liveout), "" ); 645 } 646 647 // Copies do not define a new value and so do not interfere. 648 // Remove the copies source from the liveout set before interfering. 649 uint idx = n->is_Copy(); 650 if( idx ) { 651 uint x = n2lidx(n->in(idx)); 652 if( liveout.remove( x ) ) { 653 lrgs(x)._area -= cost; 654 // Adjust register pressure. 655 lower_pressure( &lrgs(x), j-1, b, pressure, hrp_index ); 656 assert( pressure[0] == count_int_pressure (&liveout), "" ); 657 assert( pressure[1] == count_float_pressure(&liveout), "" ); 658 } 659 } 660 } // End of if live or not 661 662 // Interfere with everything live. If the defined value must 663 // go in a particular register, just remove that register from 664 // all conflicting parties and avoid the interference. 665 666 // Make exclusions for rematerializable defs. Since rematerializable 667 // DEFs are not bound but the live range is, some uses must be bound. 668 // If we spill live range 'r', it can rematerialize at each use site 669 // according to its bindings. 670 const RegMask &rmask = lrgs(r).mask(); 671 if( lrgs(r).is_bound() && !(n->rematerialize()) && rmask.is_NotEmpty() ) { 672 // Smear odd bits; leave only aligned pairs of bits. 673 RegMask r2mask = rmask; 674 r2mask.SmearToPairs(); 675 // Check for common case 676 int r_size = lrgs(r).num_regs(); 677 OptoReg::Name r_reg = (r_size == 1) ? rmask.find_first_elem() : OptoReg::Physical; 678 679 IndexSetIterator elements(&liveout); 680 uint l; 681 while ((l = elements.next()) != 0) { 682 LRG &lrg = lrgs(l); 683 // If 'l' must spill already, do not further hack his bits. 684 // He'll get some interferences and be forced to spill later. 685 if( lrg._must_spill ) continue; 686 // Remove bound register(s) from 'l's choices 687 RegMask old = lrg.mask(); 688 uint old_size = lrg.mask_size(); 689 // Remove the bits from LRG 'r' from LRG 'l' so 'l' no 690 // longer interferes with 'r'. If 'l' requires aligned 691 // adjacent pairs, subtract out bit pairs. 692 if( lrg.num_regs() == 2 && !lrg._fat_proj ) { 693 lrg.SUBTRACT( r2mask ); 694 lrg.compute_set_mask_size(); 695 } else if( r_size != 1 ) { 696 lrg.SUBTRACT( rmask ); 697 lrg.compute_set_mask_size(); 698 } else { // Common case: size 1 bound removal 699 if( lrg.mask().Member(r_reg) ) { 700 lrg.Remove(r_reg); 701 lrg.set_mask_size(lrg.mask().is_AllStack() ? 65535:old_size-1); 702 } 703 } 704 // If 'l' goes completely dry, it must spill. 705 if( lrg.not_free() ) { 706 // Give 'l' some kind of reasonable mask, so he picks up 707 // interferences (and will spill later). 708 lrg.set_mask( old ); 709 lrg.set_mask_size(old_size); 710 must_spill++; 711 lrg._must_spill = 1; 712 lrg.set_reg(OptoReg::Name(LRG::SPILL_REG)); 713 } 714 } 715 } // End of if bound 716 717 // Now interference with everything that is live and has 718 // compatible register sets. 719 interfere_with_live(r,&liveout); 720 721 } // End of if normal register-allocated value 722 723 // Area remaining in the block 724 inst_count--; 725 cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count); 726 727 // Make all inputs live 728 if( !n->is_Phi() ) { // Phi function uses come from prior block 729 JVMState* jvms = n->jvms(); 730 uint debug_start = jvms ? jvms->debug_start() : 999999; 731 // Start loop at 1 (skip control edge) for most Nodes. 732 // SCMemProj's might be the sole use of a StoreLConditional. 733 // While StoreLConditionals set memory (the SCMemProj use) 734 // they also def flags; if that flag def is unused the 735 // allocator sees a flag-setting instruction with no use of 736 // the flags and assumes it's dead. This keeps the (useless) 737 // flag-setting behavior alive while also keeping the (useful) 738 // memory update effect. 739 for( uint k = ((n->Opcode() == Op_SCMemProj) ? 0:1); k < n->req(); k++ ) { 740 Node *def = n->in(k); 741 uint x = n2lidx(def); 742 if( !x ) continue; 743 LRG &lrg = lrgs(x); 744 // No use-side cost for spilling debug info 745 if( k < debug_start ) 746 // A USE costs twice block frequency (once for the Load, once 747 // for a Load-delay). Rematerialized uses only cost once. 748 lrg._cost += (def->rematerialize() ? b->_freq : (b->_freq + b->_freq)); 749 // It is live now 750 if( liveout.insert( x ) ) { 751 // Newly live things assumed live from here to top of block 752 lrg._area += cost; 753 // Adjust register pressure 754 if( lrg.mask().is_UP() && lrg.mask_size() ) { 755 if( lrg._is_float ) { 756 pressure[1] += lrg.reg_pressure(); 757 #ifdef EXACT_PRESSURE 758 if( pressure[1] > b->_freg_pressure ) 759 b->_freg_pressure = pressure[1]; 760 #endif 761 } else if( lrg.mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) { 762 pressure[0] += lrg.reg_pressure(); 763 #ifdef EXACT_PRESSURE 764 if( pressure[0] > b->_reg_pressure ) 765 b->_reg_pressure = pressure[0]; 766 #endif 767 } 768 } 769 assert( pressure[0] == count_int_pressure (&liveout), "" ); 770 assert( pressure[1] == count_float_pressure(&liveout), "" ); 771 } 772 assert(!(lrg._area < 0.0), "negative spill area" ); 773 } 774 } 775 } // End of reverse pass over all instructions in block 776 777 // If we run off the top of the block with high pressure and 778 // never see a hi-to-low pressure transition, just record that 779 // the whole block is high pressure. 780 if( pressure[0] > (uint)INTPRESSURE ) { 781 hrp_index[0] = 0; 782 #ifdef EXACT_PRESSURE 783 if( pressure[0] > b->_reg_pressure ) 784 b->_reg_pressure = pressure[0]; 785 #else 786 b->_reg_pressure = (uint)INTPRESSURE+1; 787 #endif 788 } 789 if( pressure[1] > (uint)FLOATPRESSURE ) { 790 hrp_index[1] = 0; 791 #ifdef EXACT_PRESSURE 792 if( pressure[1] > b->_freg_pressure ) 793 b->_freg_pressure = pressure[1]; 794 #else 795 b->_freg_pressure = (uint)FLOATPRESSURE+1; 796 #endif 797 } 798 799 // Compute high pressure indice; avoid landing in the middle of projnodes 800 j = hrp_index[0]; 801 if( j < b->_nodes.size() && j < b->end_idx()+1 ) { 802 Node *cur = b->_nodes[j]; 803 while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) { 804 j--; 805 cur = b->_nodes[j]; 806 } 807 } 808 b->_ihrp_index = j; 809 j = hrp_index[1]; 810 if( j < b->_nodes.size() && j < b->end_idx()+1 ) { 811 Node *cur = b->_nodes[j]; 812 while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) { 813 j--; 814 cur = b->_nodes[j]; 815 } 816 } 817 b->_fhrp_index = j; 818 819 #ifndef PRODUCT 820 // Gather Register Pressure Statistics 821 if( PrintOptoStatistics ) { 822 if( b->_reg_pressure > (uint)INTPRESSURE || b->_freg_pressure > (uint)FLOATPRESSURE ) 823 _high_pressure++; 824 else 825 _low_pressure++; 826 } 827 #endif 828 } // End of for all blocks 829 830 return must_spill; 831 }