Mercurial > hg > truffle
annotate src/share/vm/opto/ifg.cpp @ 2412:f9424955eb18
7029152: Ideal nodes for String intrinsics miss memory edge optimization
Summary: In Ideal() method of String intrinsics nodes look for TypeAryPtr::CHARS memory slice if memory is MergeMem. Do not unroll a loop with String intrinsics code.
Reviewed-by: never
| author | kvn |
|---|---|
| date | Wed, 30 Mar 2011 12:08:49 -0700 |
| parents | f95d63e2154a |
| children | 8c92982cbbc4 |
| rev | line source |
|---|---|
| 0 | 1 /* |
|
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2 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "compiler/oopMap.hpp" | |
| 27 #include "memory/allocation.inline.hpp" | |
| 28 #include "opto/addnode.hpp" | |
| 29 #include "opto/block.hpp" | |
| 30 #include "opto/callnode.hpp" | |
| 31 #include "opto/cfgnode.hpp" | |
| 32 #include "opto/chaitin.hpp" | |
| 33 #include "opto/coalesce.hpp" | |
| 34 #include "opto/connode.hpp" | |
| 35 #include "opto/indexSet.hpp" | |
| 36 #include "opto/machnode.hpp" | |
| 37 #include "opto/memnode.hpp" | |
| 38 #include "opto/opcodes.hpp" | |
| 0 | 39 |
| 40 #define EXACT_PRESSURE 1 | |
| 41 | |
| 42 //============================================================================= | |
| 43 //------------------------------IFG-------------------------------------------- | |
| 44 PhaseIFG::PhaseIFG( Arena *arena ) : Phase(Interference_Graph), _arena(arena) { | |
| 45 } | |
| 46 | |
| 47 //------------------------------init------------------------------------------- | |
| 48 void PhaseIFG::init( uint maxlrg ) { | |
| 49 _maxlrg = maxlrg; | |
| 50 _yanked = new (_arena) VectorSet(_arena); | |
| 51 _is_square = false; | |
| 52 // Make uninitialized adjacency lists | |
| 53 _adjs = (IndexSet*)_arena->Amalloc(sizeof(IndexSet)*maxlrg); | |
| 54 // Also make empty live range structures | |
| 55 _lrgs = (LRG *)_arena->Amalloc( maxlrg * sizeof(LRG) ); | |
| 56 memset(_lrgs,0,sizeof(LRG)*maxlrg); | |
| 57 // Init all to empty | |
| 58 for( uint i = 0; i < maxlrg; i++ ) { | |
| 59 _adjs[i].initialize(maxlrg); | |
| 60 _lrgs[i].Set_All(); | |
| 61 } | |
| 62 } | |
| 63 | |
| 64 //------------------------------add-------------------------------------------- | |
| 65 // Add edge between vertices a & b. These are sorted (triangular matrix), | |
| 66 // then the smaller number is inserted in the larger numbered array. | |
| 67 int PhaseIFG::add_edge( uint a, uint b ) { | |
| 68 lrgs(a).invalid_degree(); | |
| 69 lrgs(b).invalid_degree(); | |
| 70 // Sort a and b, so that a is bigger | |
| 71 assert( !_is_square, "only on triangular" ); | |
| 72 if( a < b ) { uint tmp = a; a = b; b = tmp; } | |
| 73 return _adjs[a].insert( b ); | |
| 74 } | |
| 75 | |
| 76 //------------------------------add_vector------------------------------------- | |
| 77 // Add an edge between 'a' and everything in the vector. | |
| 78 void PhaseIFG::add_vector( uint a, IndexSet *vec ) { | |
| 79 // IFG is triangular, so do the inserts where 'a' < 'b'. | |
| 80 assert( !_is_square, "only on triangular" ); | |
| 81 IndexSet *adjs_a = &_adjs[a]; | |
| 82 if( !vec->count() ) return; | |
| 83 | |
| 84 IndexSetIterator elements(vec); | |
| 85 uint neighbor; | |
| 86 while ((neighbor = elements.next()) != 0) { | |
| 87 add_edge( a, neighbor ); | |
| 88 } | |
| 89 } | |
| 90 | |
| 91 //------------------------------test------------------------------------------- | |
| 92 // Is there an edge between a and b? | |
| 93 int PhaseIFG::test_edge( uint a, uint b ) const { | |
| 94 // Sort a and b, so that a is larger | |
| 95 assert( !_is_square, "only on triangular" ); | |
| 96 if( a < b ) { uint tmp = a; a = b; b = tmp; } | |
| 97 return _adjs[a].member(b); | |
| 98 } | |
| 99 | |
| 100 //------------------------------SquareUp--------------------------------------- | |
| 101 // Convert triangular matrix to square matrix | |
| 102 void PhaseIFG::SquareUp() { | |
| 103 assert( !_is_square, "only on triangular" ); | |
| 104 | |
| 105 // Simple transpose | |
| 106 for( uint i = 0; i < _maxlrg; i++ ) { | |
| 107 IndexSetIterator elements(&_adjs[i]); | |
| 108 uint datum; | |
| 109 while ((datum = elements.next()) != 0) { | |
| 110 _adjs[datum].insert( i ); | |
| 111 } | |
| 112 } | |
| 113 _is_square = true; | |
| 114 } | |
| 115 | |
| 116 //------------------------------Compute_Effective_Degree----------------------- | |
| 117 // Compute effective degree in bulk | |
| 118 void PhaseIFG::Compute_Effective_Degree() { | |
| 119 assert( _is_square, "only on square" ); | |
| 120 | |
| 121 for( uint i = 0; i < _maxlrg; i++ ) | |
| 122 lrgs(i).set_degree(effective_degree(i)); | |
| 123 } | |
| 124 | |
| 125 //------------------------------test_edge_sq----------------------------------- | |
| 126 int PhaseIFG::test_edge_sq( uint a, uint b ) const { | |
| 127 assert( _is_square, "only on square" ); | |
| 128 // Swap, so that 'a' has the lesser count. Then binary search is on | |
| 129 // the smaller of a's list and b's list. | |
| 130 if( neighbor_cnt(a) > neighbor_cnt(b) ) { uint tmp = a; a = b; b = tmp; } | |
| 131 //return _adjs[a].unordered_member(b); | |
| 132 return _adjs[a].member(b); | |
| 133 } | |
| 134 | |
| 135 //------------------------------Union------------------------------------------ | |
| 136 // Union edges of B into A | |
| 137 void PhaseIFG::Union( uint a, uint b ) { | |
| 138 assert( _is_square, "only on square" ); | |
| 139 IndexSet *A = &_adjs[a]; | |
| 140 IndexSetIterator b_elements(&_adjs[b]); | |
| 141 uint datum; | |
| 142 while ((datum = b_elements.next()) != 0) { | |
| 143 if(A->insert(datum)) { | |
| 144 _adjs[datum].insert(a); | |
| 145 lrgs(a).invalid_degree(); | |
| 146 lrgs(datum).invalid_degree(); | |
| 147 } | |
| 148 } | |
| 149 } | |
| 150 | |
| 151 //------------------------------remove_node------------------------------------ | |
| 152 // Yank a Node and all connected edges from the IFG. Return a | |
| 153 // list of neighbors (edges) yanked. | |
| 154 IndexSet *PhaseIFG::remove_node( uint a ) { | |
| 155 assert( _is_square, "only on square" ); | |
| 156 assert( !_yanked->test(a), "" ); | |
| 157 _yanked->set(a); | |
| 158 | |
| 159 // I remove the LRG from all neighbors. | |
| 160 IndexSetIterator elements(&_adjs[a]); | |
| 161 LRG &lrg_a = lrgs(a); | |
| 162 uint datum; | |
| 163 while ((datum = elements.next()) != 0) { | |
| 164 _adjs[datum].remove(a); | |
| 165 lrgs(datum).inc_degree( -lrg_a.compute_degree(lrgs(datum)) ); | |
| 166 } | |
| 167 return neighbors(a); | |
| 168 } | |
| 169 | |
| 170 //------------------------------re_insert-------------------------------------- | |
| 171 // Re-insert a yanked Node. | |
| 172 void PhaseIFG::re_insert( uint a ) { | |
| 173 assert( _is_square, "only on square" ); | |
| 174 assert( _yanked->test(a), "" ); | |
| 175 (*_yanked) >>= a; | |
| 176 | |
| 177 IndexSetIterator elements(&_adjs[a]); | |
| 178 uint datum; | |
| 179 while ((datum = elements.next()) != 0) { | |
| 180 _adjs[datum].insert(a); | |
| 181 lrgs(datum).invalid_degree(); | |
| 182 } | |
| 183 } | |
| 184 | |
| 185 //------------------------------compute_degree--------------------------------- | |
| 186 // Compute the degree between 2 live ranges. If both live ranges are | |
| 187 // aligned-adjacent powers-of-2 then we use the MAX size. If either is | |
| 188 // mis-aligned (or for Fat-Projections, not-adjacent) then we have to | |
| 189 // MULTIPLY the sizes. Inspect Brigg's thesis on register pairs to see why | |
| 190 // this is so. | |
| 191 int LRG::compute_degree( LRG &l ) const { | |
| 192 int tmp; | |
| 193 int num_regs = _num_regs; | |
| 194 int nregs = l.num_regs(); | |
| 195 tmp = (_fat_proj || l._fat_proj) // either is a fat-proj? | |
| 196 ? (num_regs * nregs) // then use product | |
| 197 : MAX2(num_regs,nregs); // else use max | |
| 198 return tmp; | |
| 199 } | |
| 200 | |
| 201 //------------------------------effective_degree------------------------------- | |
| 202 // Compute effective degree for this live range. If both live ranges are | |
| 203 // aligned-adjacent powers-of-2 then we use the MAX size. If either is | |
| 204 // mis-aligned (or for Fat-Projections, not-adjacent) then we have to | |
| 205 // MULTIPLY the sizes. Inspect Brigg's thesis on register pairs to see why | |
| 206 // this is so. | |
| 207 int PhaseIFG::effective_degree( uint lidx ) const { | |
| 208 int eff = 0; | |
| 209 int num_regs = lrgs(lidx).num_regs(); | |
| 210 int fat_proj = lrgs(lidx)._fat_proj; | |
| 211 IndexSet *s = neighbors(lidx); | |
| 212 IndexSetIterator elements(s); | |
| 213 uint nidx; | |
| 214 while((nidx = elements.next()) != 0) { | |
| 215 LRG &lrgn = lrgs(nidx); | |
| 216 int nregs = lrgn.num_regs(); | |
| 217 eff += (fat_proj || lrgn._fat_proj) // either is a fat-proj? | |
| 218 ? (num_regs * nregs) // then use product | |
| 219 : MAX2(num_regs,nregs); // else use max | |
| 220 } | |
| 221 return eff; | |
| 222 } | |
| 223 | |
| 224 | |
| 225 #ifndef PRODUCT | |
| 226 //------------------------------dump------------------------------------------- | |
| 227 void PhaseIFG::dump() const { | |
| 228 tty->print_cr("-- Interference Graph --%s--", | |
| 229 _is_square ? "square" : "triangular" ); | |
| 230 if( _is_square ) { | |
| 231 for( uint i = 0; i < _maxlrg; i++ ) { | |
| 232 tty->print( (*_yanked)[i] ? "XX " : " "); | |
| 233 tty->print("L%d: { ",i); | |
| 234 IndexSetIterator elements(&_adjs[i]); | |
| 235 uint datum; | |
| 236 while ((datum = elements.next()) != 0) { | |
| 237 tty->print("L%d ", datum); | |
| 238 } | |
| 239 tty->print_cr("}"); | |
| 240 | |
| 241 } | |
| 242 return; | |
| 243 } | |
| 244 | |
| 245 // Triangular | |
| 246 for( uint i = 0; i < _maxlrg; i++ ) { | |
| 247 uint j; | |
| 248 tty->print( (*_yanked)[i] ? "XX " : " "); | |
| 249 tty->print("L%d: { ",i); | |
| 250 for( j = _maxlrg; j > i; j-- ) | |
| 251 if( test_edge(j - 1,i) ) { | |
| 252 tty->print("L%d ",j - 1); | |
| 253 } | |
| 254 tty->print("| "); | |
| 255 IndexSetIterator elements(&_adjs[i]); | |
| 256 uint datum; | |
| 257 while ((datum = elements.next()) != 0) { | |
| 258 tty->print("L%d ", datum); | |
| 259 } | |
| 260 tty->print("}\n"); | |
| 261 } | |
| 262 tty->print("\n"); | |
| 263 } | |
| 264 | |
| 265 //------------------------------stats------------------------------------------ | |
| 266 void PhaseIFG::stats() const { | |
| 267 ResourceMark rm; | |
| 268 int *h_cnt = NEW_RESOURCE_ARRAY(int,_maxlrg*2); | |
| 269 memset( h_cnt, 0, sizeof(int)*_maxlrg*2 ); | |
| 270 uint i; | |
| 271 for( i = 0; i < _maxlrg; i++ ) { | |
| 272 h_cnt[neighbor_cnt(i)]++; | |
| 273 } | |
| 274 tty->print_cr("--Histogram of counts--"); | |
| 275 for( i = 0; i < _maxlrg*2; i++ ) | |
| 276 if( h_cnt[i] ) | |
| 277 tty->print("%d/%d ",i,h_cnt[i]); | |
| 278 tty->print_cr(""); | |
| 279 } | |
| 280 | |
| 281 //------------------------------verify----------------------------------------- | |
| 282 void PhaseIFG::verify( const PhaseChaitin *pc ) const { | |
| 283 // IFG is square, sorted and no need for Find | |
| 284 for( uint i = 0; i < _maxlrg; i++ ) { | |
| 285 assert(!((*_yanked)[i]) || !neighbor_cnt(i), "Is removed completely" ); | |
| 286 IndexSet *set = &_adjs[i]; | |
| 287 IndexSetIterator elements(set); | |
| 288 uint idx; | |
| 289 uint last = 0; | |
| 290 while ((idx = elements.next()) != 0) { | |
| 291 assert( idx != i, "Must have empty diagonal"); | |
| 292 assert( pc->Find_const(idx) == idx, "Must not need Find" ); | |
| 293 assert( _adjs[idx].member(i), "IFG not square" ); | |
| 294 assert( !(*_yanked)[idx], "No yanked neighbors" ); | |
| 295 assert( last < idx, "not sorted increasing"); | |
| 296 last = idx; | |
| 297 } | |
| 298 assert( !lrgs(i)._degree_valid || | |
| 299 effective_degree(i) == lrgs(i).degree(), "degree is valid but wrong" ); | |
| 300 } | |
| 301 } | |
| 302 #endif | |
| 303 | |
| 304 //------------------------------interfere_with_live---------------------------- | |
| 305 // Interfere this register with everything currently live. Use the RegMasks | |
| 306 // to trim the set of possible interferences. Return a count of register-only | |
| 605 | 307 // interferences as an estimate of register pressure. |
| 0 | 308 void PhaseChaitin::interfere_with_live( uint r, IndexSet *liveout ) { |
| 309 uint retval = 0; | |
| 310 // Interfere with everything live. | |
| 311 const RegMask &rm = lrgs(r).mask(); | |
| 312 // Check for interference by checking overlap of regmasks. | |
| 313 // Only interfere if acceptable register masks overlap. | |
| 314 IndexSetIterator elements(liveout); | |
| 315 uint l; | |
| 316 while( (l = elements.next()) != 0 ) | |
| 317 if( rm.overlap( lrgs(l).mask() ) ) | |
| 318 _ifg->add_edge( r, l ); | |
| 319 } | |
| 320 | |
| 321 //------------------------------build_ifg_virtual------------------------------ | |
| 322 // Actually build the interference graph. Uses virtual registers only, no | |
| 323 // physical register masks. This allows me to be very aggressive when | |
| 324 // coalescing copies. Some of this aggressiveness will have to be undone | |
| 325 // later, but I'd rather get all the copies I can now (since unremoved copies | |
| 326 // at this point can end up in bad places). Copies I re-insert later I have | |
| 327 // more opportunity to insert them in low-frequency locations. | |
| 328 void PhaseChaitin::build_ifg_virtual( ) { | |
| 329 | |
| 330 // For all blocks (in any order) do... | |
| 331 for( uint i=0; i<_cfg._num_blocks; i++ ) { | |
| 332 Block *b = _cfg._blocks[i]; | |
| 333 IndexSet *liveout = _live->live(b); | |
| 334 | |
| 335 // The IFG is built by a single reverse pass over each basic block. | |
| 336 // Starting with the known live-out set, we remove things that get | |
| 337 // defined and add things that become live (essentially executing one | |
| 338 // pass of a standard LIVE analysis). Just before a Node defines a value | |
| 339 // (and removes it from the live-ness set) that value is certainly live. | |
| 340 // The defined value interferes with everything currently live. The | |
| 341 // value is then removed from the live-ness set and it's inputs are | |
| 342 // added to the live-ness set. | |
| 343 for( uint j = b->end_idx() + 1; j > 1; j-- ) { | |
| 344 Node *n = b->_nodes[j-1]; | |
| 345 | |
| 346 // Get value being defined | |
| 347 uint r = n2lidx(n); | |
| 348 | |
| 349 // Some special values do not allocate | |
| 350 if( r ) { | |
| 351 | |
| 352 // Remove from live-out set | |
| 353 liveout->remove(r); | |
| 354 | |
| 355 // Copies do not define a new value and so do not interfere. | |
| 356 // Remove the copies source from the liveout set before interfering. | |
| 357 uint idx = n->is_Copy(); | |
| 358 if( idx ) liveout->remove( n2lidx(n->in(idx)) ); | |
| 359 | |
| 360 // Interfere with everything live | |
| 361 interfere_with_live( r, liveout ); | |
| 362 } | |
| 363 | |
| 364 // Make all inputs live | |
| 365 if( !n->is_Phi() ) { // Phi function uses come from prior block | |
| 366 for( uint k = 1; k < n->req(); k++ ) | |
| 367 liveout->insert( n2lidx(n->in(k)) ); | |
| 368 } | |
| 369 | |
| 370 // 2-address instructions always have the defined value live | |
| 371 // on entry to the instruction, even though it is being defined | |
| 372 // by the instruction. We pretend a virtual copy sits just prior | |
| 373 // to the instruction and kills the src-def'd register. | |
| 374 // In other words, for 2-address instructions the defined value | |
| 375 // interferes with all inputs. | |
| 376 uint idx; | |
| 377 if( n->is_Mach() && (idx = n->as_Mach()->two_adr()) ) { | |
| 378 const MachNode *mach = n->as_Mach(); | |
| 379 // Sometimes my 2-address ADDs are commuted in a bad way. | |
| 380 // We generally want the USE-DEF register to refer to the | |
| 381 // loop-varying quantity, to avoid a copy. | |
| 382 uint op = mach->ideal_Opcode(); | |
| 383 // Check that mach->num_opnds() == 3 to ensure instruction is | |
| 384 // not subsuming constants, effectively excludes addI_cin_imm | |
| 385 // Can NOT swap for instructions like addI_cin_imm since it | |
| 386 // is adding zero to yhi + carry and the second ideal-input | |
| 387 // points to the result of adding low-halves. | |
| 388 // Checking req() and num_opnds() does NOT distinguish addI_cout from addI_cout_imm | |
| 389 if( (op == Op_AddI && mach->req() == 3 && mach->num_opnds() == 3) && | |
| 390 n->in(1)->bottom_type()->base() == Type::Int && | |
| 391 // See if the ADD is involved in a tight data loop the wrong way | |
| 392 n->in(2)->is_Phi() && | |
| 393 n->in(2)->in(2) == n ) { | |
| 394 Node *tmp = n->in(1); | |
| 395 n->set_req( 1, n->in(2) ); | |
| 396 n->set_req( 2, tmp ); | |
| 397 } | |
| 398 // Defined value interferes with all inputs | |
| 399 uint lidx = n2lidx(n->in(idx)); | |
| 400 for( uint k = 1; k < n->req(); k++ ) { | |
| 401 uint kidx = n2lidx(n->in(k)); | |
| 402 if( kidx != lidx ) | |
| 403 _ifg->add_edge( r, kidx ); | |
| 404 } | |
| 405 } | |
| 406 } // End of forall instructions in block | |
| 407 } // End of forall blocks | |
| 408 } | |
| 409 | |
| 410 //------------------------------count_int_pressure----------------------------- | |
| 411 uint PhaseChaitin::count_int_pressure( IndexSet *liveout ) { | |
| 412 IndexSetIterator elements(liveout); | |
| 413 uint lidx; | |
| 414 uint cnt = 0; | |
| 415 while ((lidx = elements.next()) != 0) { | |
| 416 if( lrgs(lidx).mask().is_UP() && | |
| 417 lrgs(lidx).mask_size() && | |
| 418 !lrgs(lidx)._is_float && | |
| 419 lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) | |
| 420 cnt += lrgs(lidx).reg_pressure(); | |
| 421 } | |
| 422 return cnt; | |
| 423 } | |
| 424 | |
| 425 //------------------------------count_float_pressure--------------------------- | |
| 426 uint PhaseChaitin::count_float_pressure( IndexSet *liveout ) { | |
| 427 IndexSetIterator elements(liveout); | |
| 428 uint lidx; | |
| 429 uint cnt = 0; | |
| 430 while ((lidx = elements.next()) != 0) { | |
| 431 if( lrgs(lidx).mask().is_UP() && | |
| 432 lrgs(lidx).mask_size() && | |
| 433 lrgs(lidx)._is_float ) | |
| 434 cnt += lrgs(lidx).reg_pressure(); | |
| 435 } | |
| 436 return cnt; | |
| 437 } | |
| 438 | |
| 439 //------------------------------lower_pressure--------------------------------- | |
| 440 // Adjust register pressure down by 1. Capture last hi-to-low transition, | |
| 441 static void lower_pressure( LRG *lrg, uint where, Block *b, uint *pressure, uint *hrp_index ) { | |
| 442 if( lrg->mask().is_UP() && lrg->mask_size() ) { | |
| 443 if( lrg->_is_float ) { | |
| 444 pressure[1] -= lrg->reg_pressure(); | |
| 445 if( pressure[1] == (uint)FLOATPRESSURE ) { | |
| 446 hrp_index[1] = where; | |
| 447 #ifdef EXACT_PRESSURE | |
| 448 if( pressure[1] > b->_freg_pressure ) | |
| 449 b->_freg_pressure = pressure[1]+1; | |
| 450 #else | |
| 451 b->_freg_pressure = (uint)FLOATPRESSURE+1; | |
| 452 #endif | |
| 453 } | |
| 454 } else if( lrg->mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) { | |
| 455 pressure[0] -= lrg->reg_pressure(); | |
| 456 if( pressure[0] == (uint)INTPRESSURE ) { | |
| 457 hrp_index[0] = where; | |
| 458 #ifdef EXACT_PRESSURE | |
| 459 if( pressure[0] > b->_reg_pressure ) | |
| 460 b->_reg_pressure = pressure[0]+1; | |
| 461 #else | |
| 462 b->_reg_pressure = (uint)INTPRESSURE+1; | |
| 463 #endif | |
| 464 } | |
| 465 } | |
| 466 } | |
| 467 } | |
| 468 | |
| 469 //------------------------------build_ifg_physical----------------------------- | |
| 470 // Build the interference graph using physical registers when available. | |
| 471 // That is, if 2 live ranges are simultaneously alive but in their acceptable | |
| 472 // register sets do not overlap, then they do not interfere. | |
| 473 uint PhaseChaitin::build_ifg_physical( ResourceArea *a ) { | |
| 474 NOT_PRODUCT( Compile::TracePhase t3("buildIFG", &_t_buildIFGphysical, TimeCompiler); ) | |
| 475 | |
| 476 uint spill_reg = LRG::SPILL_REG; | |
| 477 uint must_spill = 0; | |
| 478 | |
| 479 // For all blocks (in any order) do... | |
| 480 for( uint i = 0; i < _cfg._num_blocks; i++ ) { | |
| 481 Block *b = _cfg._blocks[i]; | |
| 482 // Clone (rather than smash in place) the liveout info, so it is alive | |
| 483 // for the "collect_gc_info" phase later. | |
| 484 IndexSet liveout(_live->live(b)); | |
| 485 uint last_inst = b->end_idx(); | |
|
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91263420e1c6
6791852: assert(b->_nodes[insidx] == n,"got insidx set incorrectly")
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486 // Compute first nonphi node index |
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91263420e1c6
6791852: assert(b->_nodes[insidx] == n,"got insidx set incorrectly")
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487 uint first_inst; |
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488 for( first_inst = 1; first_inst < last_inst; first_inst++ ) |
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489 if( !b->_nodes[first_inst]->is_Phi() ) |
| 0 | 490 break; |
| 491 | |
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492 // Spills could be inserted before CreateEx node which should be |
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493 // first instruction in block after Phis. Move CreateEx up. |
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494 for( uint insidx = first_inst; insidx < last_inst; insidx++ ) { |
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495 Node *ex = b->_nodes[insidx]; |
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496 if( ex->is_SpillCopy() ) continue; |
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497 if( insidx > first_inst && ex->is_Mach() && |
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498 ex->as_Mach()->ideal_Opcode() == Op_CreateEx ) { |
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499 // If the CreateEx isn't above all the MachSpillCopies |
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500 // then move it to the top. |
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501 b->_nodes.remove(insidx); |
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502 b->_nodes.insert(first_inst, ex); |
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503 } |
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504 // Stop once a CreateEx or any other node is found |
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505 break; |
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506 } |
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507 |
| 0 | 508 // Reset block's register pressure values for each ifg construction |
| 509 uint pressure[2], hrp_index[2]; | |
| 510 pressure[0] = pressure[1] = 0; | |
| 511 hrp_index[0] = hrp_index[1] = last_inst+1; | |
| 512 b->_reg_pressure = b->_freg_pressure = 0; | |
| 513 // Liveout things are presumed live for the whole block. We accumulate | |
| 514 // 'area' accordingly. If they get killed in the block, we'll subtract | |
| 515 // the unused part of the block from the area. | |
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516 int inst_count = last_inst - first_inst; |
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517 double cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count); |
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518 assert(!(cost < 0.0), "negative spill cost" ); |
| 0 | 519 IndexSetIterator elements(&liveout); |
| 520 uint lidx; | |
| 521 while ((lidx = elements.next()) != 0) { | |
| 522 LRG &lrg = lrgs(lidx); | |
| 523 lrg._area += cost; | |
| 524 // Compute initial register pressure | |
| 525 if( lrg.mask().is_UP() && lrg.mask_size() ) { | |
| 526 if( lrg._is_float ) { // Count float pressure | |
| 527 pressure[1] += lrg.reg_pressure(); | |
| 528 #ifdef EXACT_PRESSURE | |
| 529 if( pressure[1] > b->_freg_pressure ) | |
| 530 b->_freg_pressure = pressure[1]; | |
| 531 #endif | |
| 532 // Count int pressure, but do not count the SP, flags | |
| 533 } else if( lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) { | |
| 534 pressure[0] += lrg.reg_pressure(); | |
| 535 #ifdef EXACT_PRESSURE | |
| 536 if( pressure[0] > b->_reg_pressure ) | |
| 537 b->_reg_pressure = pressure[0]; | |
| 538 #endif | |
| 539 } | |
| 540 } | |
| 541 } | |
| 542 assert( pressure[0] == count_int_pressure (&liveout), "" ); | |
| 543 assert( pressure[1] == count_float_pressure(&liveout), "" ); | |
| 544 | |
| 545 // The IFG is built by a single reverse pass over each basic block. | |
| 546 // Starting with the known live-out set, we remove things that get | |
| 547 // defined and add things that become live (essentially executing one | |
| 548 // pass of a standard LIVE analysis). Just before a Node defines a value | |
| 549 // (and removes it from the live-ness set) that value is certainly live. | |
| 550 // The defined value interferes with everything currently live. The | |
| 551 // value is then removed from the live-ness set and it's inputs are added | |
| 552 // to the live-ness set. | |
| 553 uint j; | |
| 554 for( j = last_inst + 1; j > 1; j-- ) { | |
| 555 Node *n = b->_nodes[j - 1]; | |
| 556 | |
| 557 // Get value being defined | |
| 558 uint r = n2lidx(n); | |
| 559 | |
| 560 // Some special values do not allocate | |
| 561 if( r ) { | |
| 562 // A DEF normally costs block frequency; rematerialized values are | |
| 563 // removed from the DEF sight, so LOWER costs here. | |
| 564 lrgs(r)._cost += n->rematerialize() ? 0 : b->_freq; | |
| 565 | |
| 566 // If it is not live, then this instruction is dead. Probably caused | |
| 567 // by spilling and rematerialization. Who cares why, yank this baby. | |
| 568 if( !liveout.member(r) && n->Opcode() != Op_SafePoint ) { | |
| 569 Node *def = n->in(0); | |
| 570 if( !n->is_Proj() || | |
| 571 // Could also be a flags-projection of a dead ADD or such. | |
| 572 (n2lidx(def) && !liveout.member(n2lidx(def)) ) ) { | |
| 573 b->_nodes.remove(j - 1); | |
| 574 if( lrgs(r)._def == n ) lrgs(r)._def = 0; | |
| 575 n->disconnect_inputs(NULL); | |
| 576 _cfg._bbs.map(n->_idx,NULL); | |
| 577 n->replace_by(C->top()); | |
| 578 // Since yanking a Node from block, high pressure moves up one | |
| 579 hrp_index[0]--; | |
| 580 hrp_index[1]--; | |
| 581 continue; | |
| 582 } | |
| 583 | |
| 584 // Fat-projections kill many registers which cannot be used to | |
| 585 // hold live ranges. | |
| 586 if( lrgs(r)._fat_proj ) { | |
| 587 // Count the int-only registers | |
| 588 RegMask itmp = lrgs(r).mask(); | |
| 589 itmp.AND(*Matcher::idealreg2regmask[Op_RegI]); | |
| 590 int iregs = itmp.Size(); | |
| 591 #ifdef EXACT_PRESSURE | |
| 592 if( pressure[0]+iregs > b->_reg_pressure ) | |
| 593 b->_reg_pressure = pressure[0]+iregs; | |
| 594 #endif | |
| 595 if( pressure[0] <= (uint)INTPRESSURE && | |
| 596 pressure[0]+iregs > (uint)INTPRESSURE ) { | |
| 597 #ifndef EXACT_PRESSURE | |
| 598 b->_reg_pressure = (uint)INTPRESSURE+1; | |
| 599 #endif | |
| 600 hrp_index[0] = j-1; | |
| 601 } | |
| 602 // Count the float-only registers | |
| 603 RegMask ftmp = lrgs(r).mask(); | |
| 604 ftmp.AND(*Matcher::idealreg2regmask[Op_RegD]); | |
| 605 int fregs = ftmp.Size(); | |
| 606 #ifdef EXACT_PRESSURE | |
| 607 if( pressure[1]+fregs > b->_freg_pressure ) | |
| 608 b->_freg_pressure = pressure[1]+fregs; | |
| 609 #endif | |
| 610 if( pressure[1] <= (uint)FLOATPRESSURE && | |
| 611 pressure[1]+fregs > (uint)FLOATPRESSURE ) { | |
| 612 #ifndef EXACT_PRESSURE | |
| 613 b->_freg_pressure = (uint)FLOATPRESSURE+1; | |
| 614 #endif | |
| 615 hrp_index[1] = j-1; | |
| 616 } | |
| 617 } | |
| 618 | |
| 619 } else { // Else it is live | |
| 620 // A DEF also ends 'area' partway through the block. | |
| 621 lrgs(r)._area -= cost; | |
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622 assert(!(lrgs(r)._area < 0.0), "negative spill area" ); |
| 0 | 623 |
| 624 // Insure high score for immediate-use spill copies so they get a color | |
| 625 if( n->is_SpillCopy() | |
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626 && lrgs(r).is_singledef() // MultiDef live range can still split |
| 0 | 627 && n->outcnt() == 1 // and use must be in this block |
| 628 && _cfg._bbs[n->unique_out()->_idx] == b ) { | |
| 629 // All single-use MachSpillCopy(s) that immediately precede their | |
| 630 // use must color early. If a longer live range steals their | |
| 631 // color, the spill copy will split and may push another spill copy | |
| 632 // further away resulting in an infinite spill-split-retry cycle. | |
| 633 // Assigning a zero area results in a high score() and a good | |
| 634 // location in the simplify list. | |
| 635 // | |
| 636 | |
| 637 Node *single_use = n->unique_out(); | |
| 638 assert( b->find_node(single_use) >= j, "Use must be later in block"); | |
| 639 // Use can be earlier in block if it is a Phi, but then I should be a MultiDef | |
| 640 | |
| 641 // Find first non SpillCopy 'm' that follows the current instruction | |
| 642 // (j - 1) is index for current instruction 'n' | |
| 643 Node *m = n; | |
| 644 for( uint i = j; i <= last_inst && m->is_SpillCopy(); ++i ) { m = b->_nodes[i]; } | |
| 645 if( m == single_use ) { | |
| 646 lrgs(r)._area = 0.0; | |
| 647 } | |
| 648 } | |
| 649 | |
| 650 // Remove from live-out set | |
| 651 if( liveout.remove(r) ) { | |
| 652 // Adjust register pressure. | |
| 653 // Capture last hi-to-lo pressure transition | |
| 654 lower_pressure( &lrgs(r), j-1, b, pressure, hrp_index ); | |
| 655 assert( pressure[0] == count_int_pressure (&liveout), "" ); | |
| 656 assert( pressure[1] == count_float_pressure(&liveout), "" ); | |
| 657 } | |
| 658 | |
| 659 // Copies do not define a new value and so do not interfere. | |
| 660 // Remove the copies source from the liveout set before interfering. | |
| 661 uint idx = n->is_Copy(); | |
| 662 if( idx ) { | |
| 663 uint x = n2lidx(n->in(idx)); | |
| 664 if( liveout.remove( x ) ) { | |
| 665 lrgs(x)._area -= cost; | |
| 666 // Adjust register pressure. | |
| 667 lower_pressure( &lrgs(x), j-1, b, pressure, hrp_index ); | |
| 668 assert( pressure[0] == count_int_pressure (&liveout), "" ); | |
| 669 assert( pressure[1] == count_float_pressure(&liveout), "" ); | |
| 670 } | |
| 671 } | |
| 672 } // End of if live or not | |
| 673 | |
| 674 // Interfere with everything live. If the defined value must | |
| 675 // go in a particular register, just remove that register from | |
| 676 // all conflicting parties and avoid the interference. | |
| 677 | |
| 678 // Make exclusions for rematerializable defs. Since rematerializable | |
| 679 // DEFs are not bound but the live range is, some uses must be bound. | |
| 680 // If we spill live range 'r', it can rematerialize at each use site | |
| 681 // according to its bindings. | |
| 682 const RegMask &rmask = lrgs(r).mask(); | |
| 683 if( lrgs(r).is_bound() && !(n->rematerialize()) && rmask.is_NotEmpty() ) { | |
| 684 // Smear odd bits; leave only aligned pairs of bits. | |
| 685 RegMask r2mask = rmask; | |
| 686 r2mask.SmearToPairs(); | |
| 687 // Check for common case | |
| 688 int r_size = lrgs(r).num_regs(); | |
| 689 OptoReg::Name r_reg = (r_size == 1) ? rmask.find_first_elem() : OptoReg::Physical; | |
| 690 | |
| 691 IndexSetIterator elements(&liveout); | |
| 692 uint l; | |
| 693 while ((l = elements.next()) != 0) { | |
| 694 LRG &lrg = lrgs(l); | |
| 695 // If 'l' must spill already, do not further hack his bits. | |
| 696 // He'll get some interferences and be forced to spill later. | |
| 697 if( lrg._must_spill ) continue; | |
| 698 // Remove bound register(s) from 'l's choices | |
| 699 RegMask old = lrg.mask(); | |
| 700 uint old_size = lrg.mask_size(); | |
| 701 // Remove the bits from LRG 'r' from LRG 'l' so 'l' no | |
| 702 // longer interferes with 'r'. If 'l' requires aligned | |
| 703 // adjacent pairs, subtract out bit pairs. | |
| 704 if( lrg.num_regs() == 2 && !lrg._fat_proj ) { | |
| 705 lrg.SUBTRACT( r2mask ); | |
| 706 lrg.compute_set_mask_size(); | |
| 707 } else if( r_size != 1 ) { | |
| 708 lrg.SUBTRACT( rmask ); | |
| 709 lrg.compute_set_mask_size(); | |
| 710 } else { // Common case: size 1 bound removal | |
| 711 if( lrg.mask().Member(r_reg) ) { | |
| 712 lrg.Remove(r_reg); | |
| 713 lrg.set_mask_size(lrg.mask().is_AllStack() ? 65535:old_size-1); | |
| 714 } | |
| 715 } | |
| 716 // If 'l' goes completely dry, it must spill. | |
| 717 if( lrg.not_free() ) { | |
| 718 // Give 'l' some kind of reasonable mask, so he picks up | |
| 719 // interferences (and will spill later). | |
| 720 lrg.set_mask( old ); | |
| 721 lrg.set_mask_size(old_size); | |
| 722 must_spill++; | |
| 723 lrg._must_spill = 1; | |
| 724 lrg.set_reg(OptoReg::Name(LRG::SPILL_REG)); | |
| 725 } | |
| 726 } | |
| 727 } // End of if bound | |
| 728 | |
| 729 // Now interference with everything that is live and has | |
| 730 // compatible register sets. | |
| 731 interfere_with_live(r,&liveout); | |
| 732 | |
| 733 } // End of if normal register-allocated value | |
| 734 | |
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735 // Area remaining in the block |
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736 inst_count--; |
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737 cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count); |
| 0 | 738 |
| 739 // Make all inputs live | |
| 740 if( !n->is_Phi() ) { // Phi function uses come from prior block | |
| 741 JVMState* jvms = n->jvms(); | |
| 742 uint debug_start = jvms ? jvms->debug_start() : 999999; | |
| 743 // Start loop at 1 (skip control edge) for most Nodes. | |
| 744 // SCMemProj's might be the sole use of a StoreLConditional. | |
| 745 // While StoreLConditionals set memory (the SCMemProj use) | |
| 746 // they also def flags; if that flag def is unused the | |
| 747 // allocator sees a flag-setting instruction with no use of | |
| 748 // the flags and assumes it's dead. This keeps the (useless) | |
| 749 // flag-setting behavior alive while also keeping the (useful) | |
| 750 // memory update effect. | |
| 1212 | 751 for( uint k = ((n->Opcode() == Op_SCMemProj) ? 0:1); k < n->req(); k++ ) { |
| 0 | 752 Node *def = n->in(k); |
| 753 uint x = n2lidx(def); | |
| 754 if( !x ) continue; | |
| 755 LRG &lrg = lrgs(x); | |
| 756 // No use-side cost for spilling debug info | |
| 757 if( k < debug_start ) | |
| 758 // A USE costs twice block frequency (once for the Load, once | |
| 759 // for a Load-delay). Rematerialized uses only cost once. | |
| 760 lrg._cost += (def->rematerialize() ? b->_freq : (b->_freq + b->_freq)); | |
| 761 // It is live now | |
| 762 if( liveout.insert( x ) ) { | |
| 763 // Newly live things assumed live from here to top of block | |
| 764 lrg._area += cost; | |
| 765 // Adjust register pressure | |
| 766 if( lrg.mask().is_UP() && lrg.mask_size() ) { | |
| 767 if( lrg._is_float ) { | |
| 768 pressure[1] += lrg.reg_pressure(); | |
| 769 #ifdef EXACT_PRESSURE | |
| 770 if( pressure[1] > b->_freg_pressure ) | |
| 771 b->_freg_pressure = pressure[1]; | |
| 772 #endif | |
| 773 } else if( lrg.mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) { | |
| 774 pressure[0] += lrg.reg_pressure(); | |
| 775 #ifdef EXACT_PRESSURE | |
| 776 if( pressure[0] > b->_reg_pressure ) | |
| 777 b->_reg_pressure = pressure[0]; | |
| 778 #endif | |
| 779 } | |
| 780 } | |
| 781 assert( pressure[0] == count_int_pressure (&liveout), "" ); | |
| 782 assert( pressure[1] == count_float_pressure(&liveout), "" ); | |
| 783 } | |
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784 assert(!(lrg._area < 0.0), "negative spill area" ); |
| 0 | 785 } |
| 786 } | |
| 787 } // End of reverse pass over all instructions in block | |
| 788 | |
| 789 // If we run off the top of the block with high pressure and | |
| 790 // never see a hi-to-low pressure transition, just record that | |
| 791 // the whole block is high pressure. | |
| 792 if( pressure[0] > (uint)INTPRESSURE ) { | |
| 793 hrp_index[0] = 0; | |
| 794 #ifdef EXACT_PRESSURE | |
| 795 if( pressure[0] > b->_reg_pressure ) | |
| 796 b->_reg_pressure = pressure[0]; | |
| 797 #else | |
| 798 b->_reg_pressure = (uint)INTPRESSURE+1; | |
| 799 #endif | |
| 800 } | |
| 801 if( pressure[1] > (uint)FLOATPRESSURE ) { | |
| 802 hrp_index[1] = 0; | |
| 803 #ifdef EXACT_PRESSURE | |
| 804 if( pressure[1] > b->_freg_pressure ) | |
| 805 b->_freg_pressure = pressure[1]; | |
| 806 #else | |
| 807 b->_freg_pressure = (uint)FLOATPRESSURE+1; | |
| 808 #endif | |
| 809 } | |
| 810 | |
| 811 // Compute high pressure indice; avoid landing in the middle of projnodes | |
| 812 j = hrp_index[0]; | |
| 813 if( j < b->_nodes.size() && j < b->end_idx()+1 ) { | |
| 814 Node *cur = b->_nodes[j]; | |
| 815 while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) { | |
| 816 j--; | |
| 817 cur = b->_nodes[j]; | |
| 818 } | |
| 819 } | |
| 820 b->_ihrp_index = j; | |
| 821 j = hrp_index[1]; | |
| 822 if( j < b->_nodes.size() && j < b->end_idx()+1 ) { | |
| 823 Node *cur = b->_nodes[j]; | |
| 824 while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) { | |
| 825 j--; | |
| 826 cur = b->_nodes[j]; | |
| 827 } | |
| 828 } | |
| 829 b->_fhrp_index = j; | |
| 830 | |
| 831 #ifndef PRODUCT | |
| 832 // Gather Register Pressure Statistics | |
| 833 if( PrintOptoStatistics ) { | |
| 834 if( b->_reg_pressure > (uint)INTPRESSURE || b->_freg_pressure > (uint)FLOATPRESSURE ) | |
| 835 _high_pressure++; | |
| 836 else | |
| 837 _low_pressure++; | |
| 838 } | |
| 839 #endif | |
| 840 } // End of for all blocks | |
| 841 | |
| 842 return must_spill; | |
| 843 } |