Mercurial > hg > truffle
annotate src/share/vm/opto/reg_split.cpp @ 1693:6c9cc03d8726
6973329: C2 with Zero based COOP produces code with broken anti-dependency on x86
Summary: Recompile without subsuming loads if RA try to clone a node with anti_dependence.
Reviewed-by: never
| author | kvn |
|---|---|
| date | Wed, 11 Aug 2010 10:48:20 -0700 |
| parents | c18cbe5936b8 |
| children | f55c4f82ab9d |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2000, 2009, 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 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_reg_split.cpp.incl" | |
| 27 | |
| 28 //------------------------------Split-------------------------------------- | |
| 605 | 29 // Walk the graph in RPO and for each lrg which spills, propagate reaching |
| 30 // definitions. During propagation, split the live range around regions of | |
| 0 | 31 // High Register Pressure (HRP). If a Def is in a region of Low Register |
| 32 // Pressure (LRP), it will not get spilled until we encounter a region of | |
| 33 // HRP between it and one of its uses. We will spill at the transition | |
| 34 // point between LRP and HRP. Uses in the HRP region will use the spilled | |
| 35 // Def. The first Use outside the HRP region will generate a SpillCopy to | |
| 36 // hoist the live range back up into a register, and all subsequent uses | |
| 37 // will use that new Def until another HRP region is encountered. Defs in | |
| 38 // HRP regions will get trailing SpillCopies to push the LRG down into the | |
| 39 // stack immediately. | |
| 40 // | |
| 41 // As a side effect, unlink from (hence make dead) coalesced copies. | |
| 42 // | |
| 43 | |
| 44 static const char out_of_nodes[] = "out of nodes during split"; | |
| 45 | |
| 46 //------------------------------get_spillcopy_wide----------------------------- | |
| 47 // Get a SpillCopy node with wide-enough masks. Use the 'wide-mask', the | |
| 48 // wide ideal-register spill-mask if possible. If the 'wide-mask' does | |
| 49 // not cover the input (or output), use the input (or output) mask instead. | |
| 50 Node *PhaseChaitin::get_spillcopy_wide( Node *def, Node *use, uint uidx ) { | |
| 51 // If ideal reg doesn't exist we've got a bad schedule happening | |
| 52 // that is forcing us to spill something that isn't spillable. | |
| 53 // Bail rather than abort | |
| 54 int ireg = def->ideal_reg(); | |
| 55 if( ireg == 0 || ireg == Op_RegFlags ) { | |
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56 assert(false, "attempted to spill a non-spillable item"); |
| 0 | 57 C->record_method_not_compilable("attempted to spill a non-spillable item"); |
| 58 return NULL; | |
| 59 } | |
| 60 if (C->check_node_count(NodeLimitFudgeFactor, out_of_nodes)) { | |
| 61 return NULL; | |
| 62 } | |
| 63 const RegMask *i_mask = &def->out_RegMask(); | |
| 64 const RegMask *w_mask = C->matcher()->idealreg2spillmask[ireg]; | |
| 65 const RegMask *o_mask = use ? &use->in_RegMask(uidx) : w_mask; | |
| 66 const RegMask *w_i_mask = w_mask->overlap( *i_mask ) ? w_mask : i_mask; | |
| 67 const RegMask *w_o_mask; | |
| 68 | |
| 69 if( w_mask->overlap( *o_mask ) && // Overlap AND | |
| 70 ((ireg != Op_RegL && ireg != Op_RegD // Single use or aligned | |
| 71 #ifdef _LP64 | |
| 72 && ireg != Op_RegP | |
| 73 #endif | |
| 74 ) || o_mask->is_aligned_Pairs()) ) { | |
| 75 // Don't come here for mis-aligned doubles | |
| 76 w_o_mask = w_mask; | |
| 77 } else { // wide ideal mask does not overlap with o_mask | |
| 78 // Mis-aligned doubles come here and XMM->FPR moves on x86. | |
| 79 w_o_mask = o_mask; // Must target desired registers | |
| 80 // Does the ideal-reg-mask overlap with o_mask? I.e., can I use | |
| 81 // a reg-reg move or do I need a trip across register classes | |
| 82 // (and thus through memory)? | |
| 83 if( !C->matcher()->idealreg2regmask[ireg]->overlap( *o_mask) && o_mask->is_UP() ) | |
| 84 // Here we assume a trip through memory is required. | |
| 85 w_i_mask = &C->FIRST_STACK_mask(); | |
| 86 } | |
| 87 return new (C) MachSpillCopyNode( def, *w_i_mask, *w_o_mask ); | |
| 88 } | |
| 89 | |
| 90 //------------------------------insert_proj------------------------------------ | |
| 605 | 91 // Insert the spill at chosen location. Skip over any intervening Proj's or |
| 0 | 92 // Phis. Skip over a CatchNode and projs, inserting in the fall-through block |
| 93 // instead. Update high-pressure indices. Create a new live range. | |
| 94 void PhaseChaitin::insert_proj( Block *b, uint i, Node *spill, uint maxlrg ) { | |
| 95 // Skip intervening ProjNodes. Do not insert between a ProjNode and | |
| 96 // its definer. | |
| 97 while( i < b->_nodes.size() && | |
| 98 (b->_nodes[i]->is_Proj() || | |
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99 b->_nodes[i]->is_Phi() ) ) |
| 0 | 100 i++; |
| 101 | |
| 102 // Do not insert between a call and his Catch | |
| 103 if( b->_nodes[i]->is_Catch() ) { | |
| 104 // Put the instruction at the top of the fall-thru block. | |
| 105 // Find the fall-thru projection | |
| 106 while( 1 ) { | |
| 107 const CatchProjNode *cp = b->_nodes[++i]->as_CatchProj(); | |
| 108 if( cp->_con == CatchProjNode::fall_through_index ) | |
| 109 break; | |
| 110 } | |
| 111 int sidx = i - b->end_idx()-1; | |
| 112 b = b->_succs[sidx]; // Switch to successor block | |
| 113 i = 1; // Right at start of block | |
| 114 } | |
| 115 | |
| 116 b->_nodes.insert(i,spill); // Insert node in block | |
| 117 _cfg._bbs.map(spill->_idx,b); // Update node->block mapping to reflect | |
| 118 // Adjust the point where we go hi-pressure | |
| 119 if( i <= b->_ihrp_index ) b->_ihrp_index++; | |
| 120 if( i <= b->_fhrp_index ) b->_fhrp_index++; | |
| 121 | |
| 122 // Assign a new Live Range Number to the SpillCopy and grow | |
| 123 // the node->live range mapping. | |
| 124 new_lrg(spill,maxlrg); | |
| 125 } | |
| 126 | |
| 127 //------------------------------split_DEF-------------------------------------- | |
| 605 | 128 // There are four categories of Split; UP/DOWN x DEF/USE |
| 0 | 129 // Only three of these really occur as DOWN/USE will always color |
| 130 // Any Split with a DEF cannot CISC-Spill now. Thus we need | |
| 131 // two helper routines, one for Split DEFS (insert after instruction), | |
| 132 // one for Split USES (insert before instruction). DEF insertion | |
| 133 // happens inside Split, where the Leaveblock array is updated. | |
| 134 uint PhaseChaitin::split_DEF( Node *def, Block *b, int loc, uint maxlrg, Node **Reachblock, Node **debug_defs, GrowableArray<uint> splits, int slidx ) { | |
| 135 #ifdef ASSERT | |
| 136 // Increment the counter for this lrg | |
| 137 splits.at_put(slidx, splits.at(slidx)+1); | |
| 138 #endif | |
| 139 // If we are spilling the memory op for an implicit null check, at the | |
| 140 // null check location (ie - null check is in HRP block) we need to do | |
| 141 // the null-check first, then spill-down in the following block. | |
| 142 // (The implicit_null_check function ensures the use is also dominated | |
| 143 // by the branch-not-taken block.) | |
| 144 Node *be = b->end(); | |
| 145 if( be->is_MachNullCheck() && be->in(1) == def && def == b->_nodes[loc] ) { | |
| 146 // Spill goes in the branch-not-taken block | |
| 147 b = b->_succs[b->_nodes[b->end_idx()+1]->Opcode() == Op_IfTrue]; | |
| 148 loc = 0; // Just past the Region | |
| 149 } | |
| 150 assert( loc >= 0, "must insert past block head" ); | |
| 151 | |
| 152 // Get a def-side SpillCopy | |
| 153 Node *spill = get_spillcopy_wide(def,NULL,0); | |
| 154 // Did we fail to split?, then bail | |
| 155 if (!spill) { | |
| 156 return 0; | |
| 157 } | |
| 158 | |
| 159 // Insert the spill at chosen location | |
| 160 insert_proj( b, loc+1, spill, maxlrg++); | |
| 161 | |
| 162 // Insert new node into Reaches array | |
| 163 Reachblock[slidx] = spill; | |
| 164 // Update debug list of reaching down definitions by adding this one | |
| 165 debug_defs[slidx] = spill; | |
| 166 | |
| 167 // return updated count of live ranges | |
| 168 return maxlrg; | |
| 169 } | |
| 170 | |
| 171 //------------------------------split_USE-------------------------------------- | |
| 172 // Splits at uses can involve redeffing the LRG, so no CISC Spilling there. | |
| 173 // Debug uses want to know if def is already stack enabled. | |
| 174 uint PhaseChaitin::split_USE( Node *def, Block *b, Node *use, uint useidx, uint maxlrg, bool def_down, bool cisc_sp, GrowableArray<uint> splits, int slidx ) { | |
| 175 #ifdef ASSERT | |
| 176 // Increment the counter for this lrg | |
| 177 splits.at_put(slidx, splits.at(slidx)+1); | |
| 178 #endif | |
| 179 | |
| 180 // Some setup stuff for handling debug node uses | |
| 181 JVMState* jvms = use->jvms(); | |
| 182 uint debug_start = jvms ? jvms->debug_start() : 999999; | |
| 183 uint debug_end = jvms ? jvms->debug_end() : 999999; | |
| 184 | |
| 185 //------------------------------------------- | |
| 186 // Check for use of debug info | |
| 187 if (useidx >= debug_start && useidx < debug_end) { | |
| 188 // Actually it's perfectly legal for constant debug info to appear | |
| 189 // just unlikely. In this case the optimizer left a ConI of a 4 | |
| 190 // as both inputs to a Phi with only a debug use. It's a single-def | |
| 191 // live range of a rematerializable value. The live range spills, | |
| 192 // rematerializes and now the ConI directly feeds into the debug info. | |
| 193 // assert(!def->is_Con(), "constant debug info already constructed directly"); | |
| 194 | |
| 195 // Special split handling for Debug Info | |
| 196 // If DEF is DOWN, just hook the edge and return | |
| 197 // If DEF is UP, Split it DOWN for this USE. | |
| 198 if( def->is_Mach() ) { | |
| 199 if( def_down ) { | |
| 200 // DEF is DOWN, so connect USE directly to the DEF | |
| 201 use->set_req(useidx, def); | |
| 202 } else { | |
| 203 // Block and index where the use occurs. | |
| 204 Block *b = _cfg._bbs[use->_idx]; | |
| 205 // Put the clone just prior to use | |
| 206 int bindex = b->find_node(use); | |
| 207 // DEF is UP, so must copy it DOWN and hook in USE | |
| 208 // Insert SpillCopy before the USE, which uses DEF as its input, | |
| 209 // and defs a new live range, which is used by this node. | |
| 210 Node *spill = get_spillcopy_wide(def,use,useidx); | |
| 211 // did we fail to split? | |
| 212 if (!spill) { | |
| 213 // Bail | |
| 214 return 0; | |
| 215 } | |
| 216 // insert into basic block | |
| 217 insert_proj( b, bindex, spill, maxlrg++ ); | |
| 218 // Use the new split | |
| 219 use->set_req(useidx,spill); | |
| 220 } | |
| 221 // No further split handling needed for this use | |
| 222 return maxlrg; | |
| 223 } // End special splitting for debug info live range | |
| 224 } // If debug info | |
| 225 | |
| 226 // CISC-SPILLING | |
| 227 // Finally, check to see if USE is CISC-Spillable, and if so, | |
| 228 // gather_lrg_masks will add the flags bit to its mask, and | |
| 229 // no use side copy is needed. This frees up the live range | |
| 230 // register choices without causing copy coalescing, etc. | |
| 231 if( UseCISCSpill && cisc_sp ) { | |
| 232 int inp = use->cisc_operand(); | |
| 233 if( inp != AdlcVMDeps::Not_cisc_spillable ) | |
| 234 // Convert operand number to edge index number | |
| 235 inp = use->as_Mach()->operand_index(inp); | |
| 236 if( inp == (int)useidx ) { | |
| 237 use->set_req(useidx, def); | |
| 238 #ifndef PRODUCT | |
| 239 if( TraceCISCSpill ) { | |
| 240 tty->print(" set_split: "); | |
| 241 use->dump(); | |
| 242 } | |
| 243 #endif | |
| 244 return maxlrg; | |
| 245 } | |
| 246 } | |
| 247 | |
| 248 //------------------------------------------- | |
| 249 // Insert a Copy before the use | |
| 250 | |
| 251 // Block and index where the use occurs. | |
| 252 int bindex; | |
| 253 // Phi input spill-copys belong at the end of the prior block | |
| 254 if( use->is_Phi() ) { | |
| 255 b = _cfg._bbs[b->pred(useidx)->_idx]; | |
| 256 bindex = b->end_idx(); | |
| 257 } else { | |
| 258 // Put the clone just prior to use | |
| 259 bindex = b->find_node(use); | |
| 260 } | |
| 261 | |
| 262 Node *spill = get_spillcopy_wide( def, use, useidx ); | |
| 263 if( !spill ) return 0; // Bailed out | |
| 264 // Insert SpillCopy before the USE, which uses the reaching DEF as | |
| 265 // its input, and defs a new live range, which is used by this node. | |
| 266 insert_proj( b, bindex, spill, maxlrg++ ); | |
| 267 // Use the spill/clone | |
| 268 use->set_req(useidx,spill); | |
| 269 | |
| 270 // return updated live range count | |
| 271 return maxlrg; | |
| 272 } | |
| 273 | |
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274 //------------------------------clone_node---------------------------- |
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275 // Clone node with anti dependence check. |
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276 Node* clone_node(Node* def, Block *b, Compile* C) { |
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277 if (def->needs_anti_dependence_check()) { |
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278 #ifdef ASSERT |
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279 if (Verbose) { |
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280 tty->print_cr("RA attempts to clone node with anti_dependence:"); |
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281 def->dump(-1); tty->cr(); |
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282 tty->print_cr("into block:"); |
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283 b->dump(); |
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284 } |
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285 #endif |
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286 if (C->subsume_loads() == true && !C->failing()) { |
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287 // Retry with subsume_loads == false |
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288 // If this is the first failure, the sentinel string will "stick" |
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289 // to the Compile object, and the C2Compiler will see it and retry. |
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290 C->record_failure(C2Compiler::retry_no_subsuming_loads()); |
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291 } else { |
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292 // Bailout without retry |
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293 C->record_method_not_compilable("RA Split failed: attempt to clone node with anti_dependence"); |
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294 } |
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295 return 0; |
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296 } |
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297 return def->clone(); |
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298 } |
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299 |
| 0 | 300 //------------------------------split_Rematerialize---------------------------- |
| 301 // Clone a local copy of the def. | |
| 302 Node *PhaseChaitin::split_Rematerialize( Node *def, Block *b, uint insidx, uint &maxlrg, GrowableArray<uint> splits, int slidx, uint *lrg2reach, Node **Reachblock, bool walkThru ) { | |
| 303 // The input live ranges will be stretched to the site of the new | |
| 304 // instruction. They might be stretched past a def and will thus | |
| 305 // have the old and new values of the same live range alive at the | |
| 306 // same time - a definite no-no. Split out private copies of | |
| 307 // the inputs. | |
| 308 if( def->req() > 1 ) { | |
| 309 for( uint i = 1; i < def->req(); i++ ) { | |
| 310 Node *in = def->in(i); | |
| 311 // Check for single-def (LRG cannot redefined) | |
| 312 uint lidx = n2lidx(in); | |
| 313 if( lidx >= _maxlrg ) continue; // Value is a recent spill-copy | |
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314 if (lrgs(lidx).is_singledef()) continue; |
| 0 | 315 |
| 316 Block *b_def = _cfg._bbs[def->_idx]; | |
| 317 int idx_def = b_def->find_node(def); | |
| 318 Node *in_spill = get_spillcopy_wide( in, def, i ); | |
| 319 if( !in_spill ) return 0; // Bailed out | |
| 320 insert_proj(b_def,idx_def,in_spill,maxlrg++); | |
| 321 if( b_def == b ) | |
| 322 insidx++; | |
| 323 def->set_req(i,in_spill); | |
| 324 } | |
| 325 } | |
| 326 | |
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327 Node *spill = clone_node(def, b, C); |
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328 if (spill == NULL || C->check_node_count(NodeLimitFudgeFactor, out_of_nodes)) { |
| 0 | 329 // Check when generating nodes |
| 330 return 0; | |
| 331 } | |
| 332 | |
| 333 // See if any inputs are currently being spilled, and take the | |
| 334 // latest copy of spilled inputs. | |
| 335 if( spill->req() > 1 ) { | |
| 336 for( uint i = 1; i < spill->req(); i++ ) { | |
| 337 Node *in = spill->in(i); | |
| 338 uint lidx = Find_id(in); | |
| 339 | |
| 340 // Walk backwards thru spill copy node intermediates | |
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341 if (walkThru) { |
| 0 | 342 while ( in->is_SpillCopy() && lidx >= _maxlrg ) { |
| 343 in = in->in(1); | |
| 344 lidx = Find_id(in); | |
| 345 } | |
| 346 | |
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347 if (lidx < _maxlrg && lrgs(lidx).is_multidef()) { |
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348 // walkThru found a multidef LRG, which is unsafe to use, so |
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349 // just keep the original def used in the clone. |
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350 in = spill->in(i); |
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351 lidx = Find_id(in); |
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352 } |
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353 } |
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354 |
| 0 | 355 if( lidx < _maxlrg && lrgs(lidx).reg() >= LRG::SPILL_REG ) { |
| 356 Node *rdef = Reachblock[lrg2reach[lidx]]; | |
| 357 if( rdef ) spill->set_req(i,rdef); | |
| 358 } | |
| 359 } | |
| 360 } | |
| 361 | |
| 362 | |
| 363 assert( spill->out_RegMask().is_UP(), "rematerialize to a reg" ); | |
| 364 // Rematerialized op is def->spilled+1 | |
| 365 set_was_spilled(spill); | |
| 366 if( _spilled_once.test(def->_idx) ) | |
| 367 set_was_spilled(spill); | |
| 368 | |
| 369 insert_proj( b, insidx, spill, maxlrg++ ); | |
| 370 #ifdef ASSERT | |
| 371 // Increment the counter for this lrg | |
| 372 splits.at_put(slidx, splits.at(slidx)+1); | |
| 373 #endif | |
| 374 // See if the cloned def kills any flags, and copy those kills as well | |
| 375 uint i = insidx+1; | |
| 376 if( clone_projs( b, i, def, spill, maxlrg ) ) { | |
| 377 // Adjust the point where we go hi-pressure | |
| 378 if( i <= b->_ihrp_index ) b->_ihrp_index++; | |
| 379 if( i <= b->_fhrp_index ) b->_fhrp_index++; | |
| 380 } | |
| 381 | |
| 382 return spill; | |
| 383 } | |
| 384 | |
| 385 //------------------------------is_high_pressure------------------------------- | |
| 386 // Function to compute whether or not this live range is "high pressure" | |
| 387 // in this block - whether it spills eagerly or not. | |
| 388 bool PhaseChaitin::is_high_pressure( Block *b, LRG *lrg, uint insidx ) { | |
| 389 if( lrg->_was_spilled1 ) return true; | |
| 390 // Forced spilling due to conflict? Then split only at binding uses | |
| 391 // or defs, not for supposed capacity problems. | |
| 392 // CNC - Turned off 7/8/99, causes too much spilling | |
| 393 // if( lrg->_is_bound ) return false; | |
| 394 | |
| 395 // Not yet reached the high-pressure cutoff point, so low pressure | |
| 396 uint hrp_idx = lrg->_is_float ? b->_fhrp_index : b->_ihrp_index; | |
| 397 if( insidx < hrp_idx ) return false; | |
| 398 // Register pressure for the block as a whole depends on reg class | |
| 399 int block_pres = lrg->_is_float ? b->_freg_pressure : b->_reg_pressure; | |
| 400 // Bound live ranges will split at the binding points first; | |
| 401 // Intermediate splits should assume the live range's register set | |
| 402 // got "freed up" and that num_regs will become INT_PRESSURE. | |
| 403 int bound_pres = lrg->_is_float ? FLOATPRESSURE : INTPRESSURE; | |
| 404 // Effective register pressure limit. | |
| 405 int lrg_pres = (lrg->get_invalid_mask_size() > lrg->num_regs()) | |
| 406 ? (lrg->get_invalid_mask_size() >> (lrg->num_regs()-1)) : bound_pres; | |
| 407 // High pressure if block pressure requires more register freedom | |
| 408 // than live range has. | |
| 409 return block_pres >= lrg_pres; | |
| 410 } | |
| 411 | |
| 412 | |
| 413 //------------------------------prompt_use--------------------------------- | |
| 414 // True if lidx is used before any real register is def'd in the block | |
| 415 bool PhaseChaitin::prompt_use( Block *b, uint lidx ) { | |
| 416 if( lrgs(lidx)._was_spilled2 ) return false; | |
| 417 | |
| 418 // Scan block for 1st use. | |
| 419 for( uint i = 1; i <= b->end_idx(); i++ ) { | |
| 420 Node *n = b->_nodes[i]; | |
| 421 // Ignore PHI use, these can be up or down | |
| 422 if( n->is_Phi() ) continue; | |
| 423 for( uint j = 1; j < n->req(); j++ ) | |
| 424 if( Find_id(n->in(j)) == lidx ) | |
| 425 return true; // Found 1st use! | |
| 426 if( n->out_RegMask().is_NotEmpty() ) return false; | |
| 427 } | |
| 428 return false; | |
| 429 } | |
| 430 | |
| 431 //------------------------------Split-------------------------------------- | |
| 432 //----------Split Routine---------- | |
| 433 // ***** NEW SPLITTING HEURISTIC ***** | |
| 434 // DEFS: If the DEF is in a High Register Pressure(HRP) Block, split there. | |
| 435 // Else, no split unless there is a HRP block between a DEF and | |
| 436 // one of its uses, and then split at the HRP block. | |
| 437 // | |
| 438 // USES: If USE is in HRP, split at use to leave main LRG on stack. | |
| 439 // Else, hoist LRG back up to register only (ie - split is also DEF) | |
| 440 // We will compute a new maxlrg as we go | |
| 441 uint PhaseChaitin::Split( uint maxlrg ) { | |
| 442 NOT_PRODUCT( Compile::TracePhase t3("regAllocSplit", &_t_regAllocSplit, TimeCompiler); ) | |
| 443 | |
| 444 uint bidx, pidx, slidx, insidx, inpidx, twoidx; | |
| 445 uint non_phi = 1, spill_cnt = 0; | |
| 446 Node **Reachblock; | |
| 447 Node *n1, *n2, *n3; | |
| 448 Node_List *defs,*phis; | |
| 449 bool *UPblock; | |
| 450 bool u1, u2, u3; | |
| 451 Block *b, *pred; | |
| 452 PhiNode *phi; | |
| 453 GrowableArray<uint> lidxs; | |
| 454 | |
| 455 // Array of counters to count splits per live range | |
| 456 GrowableArray<uint> splits; | |
| 457 | |
| 458 //----------Setup Code---------- | |
| 459 // Create a convenient mapping from lrg numbers to reaches/leaves indices | |
| 460 uint *lrg2reach = NEW_RESOURCE_ARRAY( uint, _maxlrg ); | |
| 461 // Keep track of DEFS & Phis for later passes | |
| 462 defs = new Node_List(); | |
| 463 phis = new Node_List(); | |
| 464 // Gather info on which LRG's are spilling, and build maps | |
| 465 for( bidx = 1; bidx < _maxlrg; bidx++ ) { | |
| 466 if( lrgs(bidx).alive() && lrgs(bidx).reg() >= LRG::SPILL_REG ) { | |
| 467 assert(!lrgs(bidx).mask().is_AllStack(),"AllStack should color"); | |
| 468 lrg2reach[bidx] = spill_cnt; | |
| 469 spill_cnt++; | |
| 470 lidxs.append(bidx); | |
| 471 #ifdef ASSERT | |
| 472 // Initialize the split counts to zero | |
| 473 splits.append(0); | |
| 474 #endif | |
| 475 #ifndef PRODUCT | |
| 476 if( PrintOpto && WizardMode && lrgs(bidx)._was_spilled1 ) | |
| 477 tty->print_cr("Warning, 2nd spill of L%d",bidx); | |
| 478 #endif | |
| 479 } | |
| 480 } | |
| 481 | |
| 482 // Create side arrays for propagating reaching defs info. | |
| 483 // Each block needs a node pointer for each spilling live range for the | |
| 484 // Def which is live into the block. Phi nodes handle multiple input | |
| 485 // Defs by querying the output of their predecessor blocks and resolving | |
| 486 // them to a single Def at the phi. The pointer is updated for each | |
| 487 // Def in the block, and then becomes the output for the block when | |
| 488 // processing of the block is complete. We also need to track whether | |
| 489 // a Def is UP or DOWN. UP means that it should get a register (ie - | |
| 490 // it is always in LRP regions), and DOWN means that it is probably | |
| 491 // on the stack (ie - it crosses HRP regions). | |
| 492 Node ***Reaches = NEW_RESOURCE_ARRAY( Node**, _cfg._num_blocks+1 ); | |
| 493 bool **UP = NEW_RESOURCE_ARRAY( bool*, _cfg._num_blocks+1 ); | |
| 494 Node **debug_defs = NEW_RESOURCE_ARRAY( Node*, spill_cnt ); | |
| 495 VectorSet **UP_entry= NEW_RESOURCE_ARRAY( VectorSet*, spill_cnt ); | |
| 496 | |
| 497 // Initialize Reaches & UP | |
| 498 for( bidx = 0; bidx < _cfg._num_blocks+1; bidx++ ) { | |
| 499 Reaches[bidx] = NEW_RESOURCE_ARRAY( Node*, spill_cnt ); | |
| 500 UP[bidx] = NEW_RESOURCE_ARRAY( bool, spill_cnt ); | |
| 501 Node **Reachblock = Reaches[bidx]; | |
| 502 bool *UPblock = UP[bidx]; | |
| 503 for( slidx = 0; slidx < spill_cnt; slidx++ ) { | |
| 504 UPblock[slidx] = true; // Assume they start in registers | |
| 505 Reachblock[slidx] = NULL; // Assume that no def is present | |
| 506 } | |
| 507 } | |
| 508 | |
| 509 // Initialize to array of empty vectorsets | |
| 510 for( slidx = 0; slidx < spill_cnt; slidx++ ) | |
| 511 UP_entry[slidx] = new VectorSet(Thread::current()->resource_area()); | |
| 512 | |
| 513 //----------PASS 1---------- | |
| 514 //----------Propagation & Node Insertion Code---------- | |
| 515 // Walk the Blocks in RPO for DEF & USE info | |
| 516 for( bidx = 0; bidx < _cfg._num_blocks; bidx++ ) { | |
| 517 | |
| 518 if (C->check_node_count(spill_cnt, out_of_nodes)) { | |
| 519 return 0; | |
| 520 } | |
| 521 | |
| 522 b = _cfg._blocks[bidx]; | |
| 523 // Reaches & UP arrays for this block | |
| 524 Reachblock = Reaches[b->_pre_order]; | |
| 525 UPblock = UP[b->_pre_order]; | |
| 526 // Reset counter of start of non-Phi nodes in block | |
| 527 non_phi = 1; | |
| 528 //----------Block Entry Handling---------- | |
| 529 // Check for need to insert a new phi | |
| 530 // Cycle through this block's predecessors, collecting Reaches | |
| 531 // info for each spilled LRG. If they are identical, no phi is | |
| 532 // needed. If they differ, check for a phi, and insert if missing, | |
| 533 // or update edges if present. Set current block's Reaches set to | |
| 534 // be either the phi's or the reaching def, as appropriate. | |
| 535 // If no Phi is needed, check if the LRG needs to spill on entry | |
| 536 // to the block due to HRP. | |
| 537 for( slidx = 0; slidx < spill_cnt; slidx++ ) { | |
| 538 // Grab the live range number | |
| 539 uint lidx = lidxs.at(slidx); | |
| 540 // Do not bother splitting or putting in Phis for single-def | |
| 541 // rematerialized live ranges. This happens alot to constants | |
| 542 // with long live ranges. | |
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543 if( lrgs(lidx).is_singledef() && |
| 0 | 544 lrgs(lidx)._def->rematerialize() ) { |
| 545 // reset the Reaches & UP entries | |
| 546 Reachblock[slidx] = lrgs(lidx)._def; | |
| 547 UPblock[slidx] = true; | |
| 548 // Record following instruction in case 'n' rematerializes and | |
| 549 // kills flags | |
| 550 Block *pred1 = _cfg._bbs[b->pred(1)->_idx]; | |
| 551 continue; | |
| 552 } | |
| 553 | |
| 554 // Initialize needs_phi and needs_split | |
| 555 bool needs_phi = false; | |
| 556 bool needs_split = false; | |
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557 bool has_phi = false; |
| 0 | 558 // Walk the predecessor blocks to check inputs for that live range |
| 559 // Grab predecessor block header | |
| 560 n1 = b->pred(1); | |
| 561 // Grab the appropriate reaching def info for inpidx | |
| 562 pred = _cfg._bbs[n1->_idx]; | |
| 563 pidx = pred->_pre_order; | |
| 564 Node **Ltmp = Reaches[pidx]; | |
| 565 bool *Utmp = UP[pidx]; | |
| 566 n1 = Ltmp[slidx]; | |
| 567 u1 = Utmp[slidx]; | |
| 568 // Initialize node for saving type info | |
| 569 n3 = n1; | |
| 570 u3 = u1; | |
| 571 | |
| 572 // Compare inputs to see if a Phi is needed | |
| 573 for( inpidx = 2; inpidx < b->num_preds(); inpidx++ ) { | |
| 574 // Grab predecessor block headers | |
| 575 n2 = b->pred(inpidx); | |
| 576 // Grab the appropriate reaching def info for inpidx | |
| 577 pred = _cfg._bbs[n2->_idx]; | |
| 578 pidx = pred->_pre_order; | |
| 579 Ltmp = Reaches[pidx]; | |
| 580 Utmp = UP[pidx]; | |
| 581 n2 = Ltmp[slidx]; | |
| 582 u2 = Utmp[slidx]; | |
| 583 // For each LRG, decide if a phi is necessary | |
| 584 if( n1 != n2 ) { | |
| 585 needs_phi = true; | |
| 586 } | |
| 587 // See if the phi has mismatched inputs, UP vs. DOWN | |
| 588 if( n1 && n2 && (u1 != u2) ) { | |
| 589 needs_split = true; | |
| 590 } | |
| 591 // Move n2/u2 to n1/u1 for next iteration | |
| 592 n1 = n2; | |
| 593 u1 = u2; | |
| 594 // Preserve a non-NULL predecessor for later type referencing | |
| 595 if( (n3 == NULL) && (n2 != NULL) ){ | |
| 596 n3 = n2; | |
| 597 u3 = u2; | |
| 598 } | |
| 599 } // End for all potential Phi inputs | |
| 600 | |
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601 // check block for appropriate phinode & update edges |
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602 for( insidx = 1; insidx <= b->end_idx(); insidx++ ) { |
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603 n1 = b->_nodes[insidx]; |
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604 // bail if this is not a phi |
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605 phi = n1->is_Phi() ? n1->as_Phi() : NULL; |
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606 if( phi == NULL ) { |
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607 // Keep track of index of first non-PhiNode instruction in block |
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608 non_phi = insidx; |
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609 // break out of the for loop as we have handled all phi nodes |
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610 break; |
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611 } |
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612 // must be looking at a phi |
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613 if( Find_id(n1) == lidxs.at(slidx) ) { |
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614 // found the necessary phi |
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615 needs_phi = false; |
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616 has_phi = true; |
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617 // initialize the Reaches entry for this LRG |
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618 Reachblock[slidx] = phi; |
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619 break; |
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620 } // end if found correct phi |
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621 } // end for all phi's |
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622 |
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623 // If a phi is needed or exist, check for it |
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624 if( needs_phi || has_phi ) { |
| 0 | 625 // add new phinode if one not already found |
| 626 if( needs_phi ) { | |
| 627 // create a new phi node and insert it into the block | |
| 628 // type is taken from left over pointer to a predecessor | |
| 629 assert(n3,"No non-NULL reaching DEF for a Phi"); | |
| 630 phi = new (C, b->num_preds()) PhiNode(b->head(), n3->bottom_type()); | |
| 631 // initialize the Reaches entry for this LRG | |
| 632 Reachblock[slidx] = phi; | |
| 633 | |
| 634 // add node to block & node_to_block mapping | |
| 635 insert_proj( b, insidx++, phi, maxlrg++ ); | |
| 636 non_phi++; | |
| 637 // Reset new phi's mapping to be the spilling live range | |
| 638 _names.map(phi->_idx, lidx); | |
| 639 assert(Find_id(phi) == lidx,"Bad update on Union-Find mapping"); | |
| 640 } // end if not found correct phi | |
| 641 // Here you have either found or created the Phi, so record it | |
| 642 assert(phi != NULL,"Must have a Phi Node here"); | |
| 643 phis->push(phi); | |
| 644 // PhiNodes should either force the LRG UP or DOWN depending | |
| 645 // on its inputs and the register pressure in the Phi's block. | |
| 646 UPblock[slidx] = true; // Assume new DEF is UP | |
| 647 // If entering a high-pressure area with no immediate use, | |
| 648 // assume Phi is DOWN | |
| 649 if( is_high_pressure( b, &lrgs(lidx), b->end_idx()) && !prompt_use(b,lidx) ) | |
| 650 UPblock[slidx] = false; | |
| 651 // If we are not split up/down and all inputs are down, then we | |
| 652 // are down | |
| 653 if( !needs_split && !u3 ) | |
| 654 UPblock[slidx] = false; | |
| 655 } // end if phi is needed | |
| 656 | |
| 657 // Do not need a phi, so grab the reaching DEF | |
| 658 else { | |
| 659 // Grab predecessor block header | |
| 660 n1 = b->pred(1); | |
| 661 // Grab the appropriate reaching def info for k | |
| 662 pred = _cfg._bbs[n1->_idx]; | |
| 663 pidx = pred->_pre_order; | |
| 664 Node **Ltmp = Reaches[pidx]; | |
| 665 bool *Utmp = UP[pidx]; | |
| 666 // reset the Reaches & UP entries | |
| 667 Reachblock[slidx] = Ltmp[slidx]; | |
| 668 UPblock[slidx] = Utmp[slidx]; | |
| 669 } // end else no Phi is needed | |
| 670 } // end for all spilling live ranges | |
| 671 // DEBUG | |
| 672 #ifndef PRODUCT | |
| 673 if(trace_spilling()) { | |
| 674 tty->print("/`\nBlock %d: ", b->_pre_order); | |
| 675 tty->print("Reaching Definitions after Phi handling\n"); | |
| 676 for( uint x = 0; x < spill_cnt; x++ ) { | |
| 677 tty->print("Spill Idx %d: UP %d: Node\n",x,UPblock[x]); | |
| 678 if( Reachblock[x] ) | |
| 679 Reachblock[x]->dump(); | |
| 680 else | |
| 681 tty->print("Undefined\n"); | |
| 682 } | |
| 683 } | |
| 684 #endif | |
| 685 | |
| 686 //----------Non-Phi Node Splitting---------- | |
| 687 // Since phi-nodes have now been handled, the Reachblock array for this | |
| 688 // block is initialized with the correct starting value for the defs which | |
| 689 // reach non-phi instructions in this block. Thus, process non-phi | |
| 690 // instructions normally, inserting SpillCopy nodes for all spill | |
| 691 // locations. | |
| 692 | |
| 693 // Memoize any DOWN reaching definitions for use as DEBUG info | |
| 694 for( insidx = 0; insidx < spill_cnt; insidx++ ) { | |
| 695 debug_defs[insidx] = (UPblock[insidx]) ? NULL : Reachblock[insidx]; | |
| 696 if( UPblock[insidx] ) // Memoize UP decision at block start | |
| 697 UP_entry[insidx]->set( b->_pre_order ); | |
| 698 } | |
| 699 | |
| 700 //----------Walk Instructions in the Block and Split---------- | |
| 701 // For all non-phi instructions in the block | |
| 702 for( insidx = 1; insidx <= b->end_idx(); insidx++ ) { | |
| 703 Node *n = b->_nodes[insidx]; | |
| 704 // Find the defining Node's live range index | |
| 705 uint defidx = Find_id(n); | |
| 706 uint cnt = n->req(); | |
| 707 | |
| 708 if( n->is_Phi() ) { | |
| 709 // Skip phi nodes after removing dead copies. | |
| 710 if( defidx < _maxlrg ) { | |
| 711 // Check for useless Phis. These appear if we spill, then | |
| 712 // coalesce away copies. Dont touch Phis in spilling live | |
| 713 // ranges; they are busy getting modifed in this pass. | |
| 714 if( lrgs(defidx).reg() < LRG::SPILL_REG ) { | |
| 715 uint i; | |
| 716 Node *u = NULL; | |
| 717 // Look for the Phi merging 2 unique inputs | |
| 718 for( i = 1; i < cnt; i++ ) { | |
| 719 // Ignore repeats and self | |
| 720 if( n->in(i) != u && n->in(i) != n ) { | |
| 721 // Found a unique input | |
| 722 if( u != NULL ) // If it's the 2nd, bail out | |
| 723 break; | |
| 724 u = n->in(i); // Else record it | |
| 725 } | |
| 726 } | |
| 727 assert( u, "at least 1 valid input expected" ); | |
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728 if( i >= cnt ) { // Found one unique input |
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6746892: Register Allocator does not process a data phi with one unique input correctly
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parents:
295
diff
changeset
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729 assert(Find_id(n) == Find_id(u), "should be the same lrg"); |
| 0 | 730 n->replace_by(u); // Then replace with unique input |
| 731 n->disconnect_inputs(NULL); | |
| 732 b->_nodes.remove(insidx); | |
| 733 insidx--; | |
| 734 b->_ihrp_index--; | |
| 735 b->_fhrp_index--; | |
| 736 } | |
| 737 } | |
| 738 } | |
| 739 continue; | |
| 740 } | |
| 741 assert( insidx > b->_ihrp_index || | |
| 742 (b->_reg_pressure < (uint)INTPRESSURE) || | |
| 743 b->_ihrp_index > 4000000 || | |
| 744 b->_ihrp_index >= b->end_idx() || | |
| 745 !b->_nodes[b->_ihrp_index]->is_Proj(), "" ); | |
| 746 assert( insidx > b->_fhrp_index || | |
| 747 (b->_freg_pressure < (uint)FLOATPRESSURE) || | |
| 748 b->_fhrp_index > 4000000 || | |
| 749 b->_fhrp_index >= b->end_idx() || | |
| 750 !b->_nodes[b->_fhrp_index]->is_Proj(), "" ); | |
| 751 | |
| 752 // ********** Handle Crossing HRP Boundry ********** | |
| 753 if( (insidx == b->_ihrp_index) || (insidx == b->_fhrp_index) ) { | |
| 754 for( slidx = 0; slidx < spill_cnt; slidx++ ) { | |
| 605 | 755 // Check for need to split at HRP boundary - split if UP |
| 0 | 756 n1 = Reachblock[slidx]; |
| 757 // bail out if no reaching DEF | |
| 758 if( n1 == NULL ) continue; | |
| 759 // bail out if live range is 'isolated' around inner loop | |
| 760 uint lidx = lidxs.at(slidx); | |
| 761 // If live range is currently UP | |
| 762 if( UPblock[slidx] ) { | |
| 763 // set location to insert spills at | |
| 764 // SPLIT DOWN HERE - NO CISC SPILL | |
| 765 if( is_high_pressure( b, &lrgs(lidx), insidx ) && | |
| 766 !n1->rematerialize() ) { | |
| 767 // If there is already a valid stack definition available, use it | |
| 768 if( debug_defs[slidx] != NULL ) { | |
| 769 Reachblock[slidx] = debug_defs[slidx]; | |
| 770 } | |
| 771 else { | |
| 772 // Insert point is just past last use or def in the block | |
| 773 int insert_point = insidx-1; | |
| 774 while( insert_point > 0 ) { | |
| 775 Node *n = b->_nodes[insert_point]; | |
| 776 // Hit top of block? Quit going backwards | |
| 777 if( n->is_Phi() ) break; | |
| 778 // Found a def? Better split after it. | |
| 779 if( n2lidx(n) == lidx ) break; | |
| 780 // Look for a use | |
| 781 uint i; | |
| 782 for( i = 1; i < n->req(); i++ ) | |
| 783 if( n2lidx(n->in(i)) == lidx ) | |
| 784 break; | |
| 785 // Found a use? Better split after it. | |
| 786 if( i < n->req() ) break; | |
| 787 insert_point--; | |
| 788 } | |
| 789 maxlrg = split_DEF( n1, b, insert_point, maxlrg, Reachblock, debug_defs, splits, slidx); | |
| 790 // If it wasn't split bail | |
| 791 if (!maxlrg) { | |
| 792 return 0; | |
| 793 } | |
| 794 insidx++; | |
| 795 } | |
| 796 // This is a new DEF, so update UP | |
| 797 UPblock[slidx] = false; | |
| 798 #ifndef PRODUCT | |
| 799 // DEBUG | |
| 800 if( trace_spilling() ) { | |
| 801 tty->print("\nNew Split DOWN DEF of Spill Idx "); | |
| 802 tty->print("%d, UP %d:\n",slidx,false); | |
| 803 n1->dump(); | |
| 804 } | |
| 805 #endif | |
| 806 } | |
| 807 } // end if LRG is UP | |
| 808 } // end for all spilling live ranges | |
| 809 assert( b->_nodes[insidx] == n, "got insidx set incorrectly" ); | |
| 810 } // end if crossing HRP Boundry | |
| 811 | |
| 812 // If the LRG index is oob, then this is a new spillcopy, skip it. | |
| 813 if( defidx >= _maxlrg ) { | |
| 814 continue; | |
| 815 } | |
| 816 LRG &deflrg = lrgs(defidx); | |
| 817 uint copyidx = n->is_Copy(); | |
| 818 // Remove coalesced copy from CFG | |
| 819 if( copyidx && defidx == n2lidx(n->in(copyidx)) ) { | |
| 820 n->replace_by( n->in(copyidx) ); | |
| 821 n->set_req( copyidx, NULL ); | |
| 822 b->_nodes.remove(insidx--); | |
| 823 b->_ihrp_index--; // Adjust the point where we go hi-pressure | |
| 824 b->_fhrp_index--; | |
| 825 continue; | |
| 826 } | |
| 827 | |
| 828 #define DERIVED 0 | |
| 829 | |
| 830 // ********** Handle USES ********** | |
| 831 bool nullcheck = false; | |
| 832 // Implicit null checks never use the spilled value | |
| 833 if( n->is_MachNullCheck() ) | |
| 834 nullcheck = true; | |
| 835 if( !nullcheck ) { | |
| 836 // Search all inputs for a Spill-USE | |
| 837 JVMState* jvms = n->jvms(); | |
| 838 uint oopoff = jvms ? jvms->oopoff() : cnt; | |
| 839 uint old_last = cnt - 1; | |
| 840 for( inpidx = 1; inpidx < cnt; inpidx++ ) { | |
| 841 // Derived/base pairs may be added to our inputs during this loop. | |
| 842 // If inpidx > old_last, then one of these new inputs is being | |
| 843 // handled. Skip the derived part of the pair, but process | |
| 844 // the base like any other input. | |
| 845 if( inpidx > old_last && ((inpidx - oopoff) & 1) == DERIVED ) { | |
| 846 continue; // skip derived_debug added below | |
| 847 } | |
| 848 // Get lidx of input | |
| 849 uint useidx = Find_id(n->in(inpidx)); | |
| 850 // Not a brand-new split, and it is a spill use | |
| 851 if( useidx < _maxlrg && lrgs(useidx).reg() >= LRG::SPILL_REG ) { | |
| 852 // Check for valid reaching DEF | |
| 853 slidx = lrg2reach[useidx]; | |
| 854 Node *def = Reachblock[slidx]; | |
| 855 assert( def != NULL, "Using Undefined Value in Split()\n"); | |
| 856 | |
| 857 // (+++) %%%% remove this in favor of pre-pass in matcher.cpp | |
| 858 // monitor references do not care where they live, so just hook | |
| 859 if ( jvms && jvms->is_monitor_use(inpidx) ) { | |
| 860 // The effect of this clone is to drop the node out of the block, | |
| 861 // so that the allocator does not see it anymore, and therefore | |
| 862 // does not attempt to assign it a register. | |
|
1693
6c9cc03d8726
6973329: C2 with Zero based COOP produces code with broken anti-dependency on x86
kvn
parents:
1552
diff
changeset
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863 def = clone_node(def, b, C); |
|
6c9cc03d8726
6973329: C2 with Zero based COOP produces code with broken anti-dependency on x86
kvn
parents:
1552
diff
changeset
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864 if (def == NULL || C->check_node_count(NodeLimitFudgeFactor, out_of_nodes)) { |
|
6c9cc03d8726
6973329: C2 with Zero based COOP produces code with broken anti-dependency on x86
kvn
parents:
1552
diff
changeset
|
865 return 0; |
|
6c9cc03d8726
6973329: C2 with Zero based COOP produces code with broken anti-dependency on x86
kvn
parents:
1552
diff
changeset
|
866 } |
| 0 | 867 _names.extend(def->_idx,0); |
| 868 _cfg._bbs.map(def->_idx,b); | |
| 869 n->set_req(inpidx, def); | |
| 870 continue; | |
| 871 } | |
| 872 | |
| 873 // Rematerializable? Then clone def at use site instead | |
| 874 // of store/load | |
| 875 if( def->rematerialize() ) { | |
| 876 int old_size = b->_nodes.size(); | |
| 877 def = split_Rematerialize( def, b, insidx, maxlrg, splits, slidx, lrg2reach, Reachblock, true ); | |
| 878 if( !def ) return 0; // Bail out | |
| 879 insidx += b->_nodes.size()-old_size; | |
| 880 } | |
| 881 | |
| 882 MachNode *mach = n->is_Mach() ? n->as_Mach() : NULL; | |
| 883 // Base pointers and oopmap references do not care where they live. | |
| 884 if ((inpidx >= oopoff) || | |
| 885 (mach && mach->ideal_Opcode() == Op_AddP && inpidx == AddPNode::Base)) { | |
| 886 if (def->rematerialize() && lrgs(useidx)._was_spilled2) { | |
| 887 // This def has been rematerialized a couple of times without | |
| 888 // progress. It doesn't care if it lives UP or DOWN, so | |
| 889 // spill it down now. | |
| 890 maxlrg = split_USE(def,b,n,inpidx,maxlrg,false,false,splits,slidx); | |
| 891 // If it wasn't split bail | |
| 892 if (!maxlrg) { | |
| 893 return 0; | |
| 894 } | |
| 895 insidx++; // Reset iterator to skip USE side split | |
| 896 } else { | |
| 897 // Just hook the def edge | |
| 898 n->set_req(inpidx, def); | |
| 899 } | |
| 900 | |
| 901 if (inpidx >= oopoff) { | |
| 902 // After oopoff, we have derived/base pairs. We must mention all | |
| 903 // derived pointers here as derived/base pairs for GC. If the | |
| 904 // derived value is spilling and we have a copy both in Reachblock | |
| 905 // (called here 'def') and debug_defs[slidx] we need to mention | |
| 906 // both in derived/base pairs or kill one. | |
| 907 Node *derived_debug = debug_defs[slidx]; | |
| 908 if( ((inpidx - oopoff) & 1) == DERIVED && // derived vs base? | |
| 909 mach && mach->ideal_Opcode() != Op_Halt && | |
| 910 derived_debug != NULL && | |
| 911 derived_debug != def ) { // Actual 2nd value appears | |
| 912 // We have already set 'def' as a derived value. | |
| 913 // Also set debug_defs[slidx] as a derived value. | |
| 914 uint k; | |
| 915 for( k = oopoff; k < cnt; k += 2 ) | |
| 916 if( n->in(k) == derived_debug ) | |
| 917 break; // Found an instance of debug derived | |
| 918 if( k == cnt ) {// No instance of debug_defs[slidx] | |
| 919 // Add a derived/base pair to cover the debug info. | |
| 920 // We have to process the added base later since it is not | |
| 921 // handled yet at this point but skip derived part. | |
| 922 assert(((n->req() - oopoff) & 1) == DERIVED, | |
| 923 "must match skip condition above"); | |
| 924 n->add_req( derived_debug ); // this will be skipped above | |
| 925 n->add_req( n->in(inpidx+1) ); // this will be processed | |
| 926 // Increment cnt to handle added input edges on | |
| 927 // subsequent iterations. | |
| 928 cnt += 2; | |
| 929 } | |
| 930 } | |
| 931 } | |
| 932 continue; | |
| 933 } | |
| 934 // Special logic for DEBUG info | |
| 935 if( jvms && b->_freq > BLOCK_FREQUENCY(0.5) ) { | |
| 936 uint debug_start = jvms->debug_start(); | |
| 937 // If this is debug info use & there is a reaching DOWN def | |
| 938 if ((debug_start <= inpidx) && (debug_defs[slidx] != NULL)) { | |
| 939 assert(inpidx < oopoff, "handle only debug info here"); | |
| 940 // Just hook it in & move on | |
| 941 n->set_req(inpidx, debug_defs[slidx]); | |
| 942 // (Note that this can make two sides of a split live at the | |
| 943 // same time: The debug def on stack, and another def in a | |
| 944 // register. The GC needs to know about both of them, but any | |
| 945 // derived pointers after oopoff will refer to only one of the | |
| 946 // two defs and the GC would therefore miss the other. Thus | |
| 947 // this hack is only allowed for debug info which is Java state | |
| 948 // and therefore never a derived pointer.) | |
| 949 continue; | |
| 950 } | |
| 951 } | |
| 952 // Grab register mask info | |
| 953 const RegMask &dmask = def->out_RegMask(); | |
| 954 const RegMask &umask = n->in_RegMask(inpidx); | |
| 955 | |
| 956 assert(inpidx < oopoff, "cannot use-split oop map info"); | |
| 957 | |
| 958 bool dup = UPblock[slidx]; | |
| 959 bool uup = umask.is_UP(); | |
| 960 | |
| 961 // Need special logic to handle bound USES. Insert a split at this | |
| 962 // bound use if we can't rematerialize the def, or if we need the | |
| 963 // split to form a misaligned pair. | |
| 964 if( !umask.is_AllStack() && | |
| 965 (int)umask.Size() <= lrgs(useidx).num_regs() && | |
| 966 (!def->rematerialize() || | |
| 967 umask.is_misaligned_Pair())) { | |
| 968 // These need a Split regardless of overlap or pressure | |
| 969 // SPLIT - NO DEF - NO CISC SPILL | |
| 970 maxlrg = split_USE(def,b,n,inpidx,maxlrg,dup,false, splits,slidx); | |
| 971 // If it wasn't split bail | |
| 972 if (!maxlrg) { | |
| 973 return 0; | |
| 974 } | |
| 975 insidx++; // Reset iterator to skip USE side split | |
| 976 continue; | |
| 977 } | |
| 978 // Here is the logic chart which describes USE Splitting: | |
| 979 // 0 = false or DOWN, 1 = true or UP | |
| 980 // | |
| 981 // Overlap | DEF | USE | Action | |
| 982 //------------------------------------------------------- | |
| 983 // 0 | 0 | 0 | Copy - mem -> mem | |
| 984 // 0 | 0 | 1 | Split-UP - Check HRP | |
| 985 // 0 | 1 | 0 | Split-DOWN - Debug Info? | |
| 986 // 0 | 1 | 1 | Copy - reg -> reg | |
| 987 // 1 | 0 | 0 | Reset Input Edge (no Split) | |
| 988 // 1 | 0 | 1 | Split-UP - Check HRP | |
| 989 // 1 | 1 | 0 | Split-DOWN - Debug Info? | |
| 990 // 1 | 1 | 1 | Reset Input Edge (no Split) | |
| 991 // | |
| 992 // So, if (dup == uup), then overlap test determines action, | |
| 993 // with true being no split, and false being copy. Else, | |
| 994 // if DEF is DOWN, Split-UP, and check HRP to decide on | |
| 995 // resetting DEF. Finally if DEF is UP, Split-DOWN, with | |
| 996 // special handling for Debug Info. | |
| 997 if( dup == uup ) { | |
| 998 if( dmask.overlap(umask) ) { | |
| 999 // Both are either up or down, and there is overlap, No Split | |
| 1000 n->set_req(inpidx, def); | |
| 1001 } | |
| 1002 else { // Both are either up or down, and there is no overlap | |
| 1003 if( dup ) { // If UP, reg->reg copy | |
| 1004 // COPY ACROSS HERE - NO DEF - NO CISC SPILL | |
| 1005 maxlrg = split_USE(def,b,n,inpidx,maxlrg,false,false, splits,slidx); | |
| 1006 // If it wasn't split bail | |
| 1007 if (!maxlrg) { | |
| 1008 return 0; | |
| 1009 } | |
| 1010 insidx++; // Reset iterator to skip USE side split | |
| 1011 } | |
| 1012 else { // DOWN, mem->mem copy | |
| 1013 // COPY UP & DOWN HERE - NO DEF - NO CISC SPILL | |
| 1014 // First Split-UP to move value into Register | |
| 1015 uint def_ideal = def->ideal_reg(); | |
| 1016 const RegMask* tmp_rm = Matcher::idealreg2regmask[def_ideal]; | |
| 1017 Node *spill = new (C) MachSpillCopyNode(def, dmask, *tmp_rm); | |
| 1018 insert_proj( b, insidx, spill, maxlrg ); | |
| 1019 // Then Split-DOWN as if previous Split was DEF | |
| 1020 maxlrg = split_USE(spill,b,n,inpidx,maxlrg,false,false, splits,slidx); | |
| 1021 // If it wasn't split bail | |
| 1022 if (!maxlrg) { | |
| 1023 return 0; | |
| 1024 } | |
| 1025 insidx += 2; // Reset iterator to skip USE side splits | |
| 1026 } | |
| 1027 } // End else no overlap | |
| 1028 } // End if dup == uup | |
| 1029 // dup != uup, so check dup for direction of Split | |
| 1030 else { | |
| 1031 if( dup ) { // If UP, Split-DOWN and check Debug Info | |
| 1032 // If this node is already a SpillCopy, just patch the edge | |
| 1033 // except the case of spilling to stack. | |
| 1034 if( n->is_SpillCopy() ) { | |
| 1035 RegMask tmp_rm(umask); | |
| 1036 tmp_rm.SUBTRACT(Matcher::STACK_ONLY_mask); | |
| 1037 if( dmask.overlap(tmp_rm) ) { | |
| 1038 if( def != n->in(inpidx) ) { | |
| 1039 n->set_req(inpidx, def); | |
| 1040 } | |
| 1041 continue; | |
| 1042 } | |
| 1043 } | |
| 1044 // COPY DOWN HERE - NO DEF - NO CISC SPILL | |
| 1045 maxlrg = split_USE(def,b,n,inpidx,maxlrg,false,false, splits,slidx); | |
| 1046 // If it wasn't split bail | |
| 1047 if (!maxlrg) { | |
| 1048 return 0; | |
| 1049 } | |
| 1050 insidx++; // Reset iterator to skip USE side split | |
| 1051 // Check for debug-info split. Capture it for later | |
| 1052 // debug splits of the same value | |
| 1053 if (jvms && jvms->debug_start() <= inpidx && inpidx < oopoff) | |
| 1054 debug_defs[slidx] = n->in(inpidx); | |
| 1055 | |
| 1056 } | |
| 1057 else { // DOWN, Split-UP and check register pressure | |
| 1058 if( is_high_pressure( b, &lrgs(useidx), insidx ) ) { | |
| 1059 // COPY UP HERE - NO DEF - CISC SPILL | |
| 1060 maxlrg = split_USE(def,b,n,inpidx,maxlrg,true,true, splits,slidx); | |
| 1061 // If it wasn't split bail | |
| 1062 if (!maxlrg) { | |
| 1063 return 0; | |
| 1064 } | |
| 1065 insidx++; // Reset iterator to skip USE side split | |
| 1066 } else { // LRP | |
| 1067 // COPY UP HERE - WITH DEF - NO CISC SPILL | |
| 1068 maxlrg = split_USE(def,b,n,inpidx,maxlrg,true,false, splits,slidx); | |
| 1069 // If it wasn't split bail | |
| 1070 if (!maxlrg) { | |
| 1071 return 0; | |
| 1072 } | |
| 1073 // Flag this lift-up in a low-pressure block as | |
| 1074 // already-spilled, so if it spills again it will | |
| 1075 // spill hard (instead of not spilling hard and | |
| 1076 // coalescing away). | |
| 1077 set_was_spilled(n->in(inpidx)); | |
| 1078 // Since this is a new DEF, update Reachblock & UP | |
| 1079 Reachblock[slidx] = n->in(inpidx); | |
| 1080 UPblock[slidx] = true; | |
| 1081 insidx++; // Reset iterator to skip USE side split | |
| 1082 } | |
| 1083 } // End else DOWN | |
| 1084 } // End dup != uup | |
| 1085 } // End if Spill USE | |
| 1086 } // End For All Inputs | |
| 1087 } // End If not nullcheck | |
| 1088 | |
| 1089 // ********** Handle DEFS ********** | |
| 1090 // DEFS either Split DOWN in HRP regions or when the LRG is bound, or | |
| 1091 // just reset the Reaches info in LRP regions. DEFS must always update | |
| 1092 // UP info. | |
| 1093 if( deflrg.reg() >= LRG::SPILL_REG ) { // Spilled? | |
| 1094 uint slidx = lrg2reach[defidx]; | |
| 1095 // Add to defs list for later assignment of new live range number | |
| 1096 defs->push(n); | |
| 1097 // Set a flag on the Node indicating it has already spilled. | |
| 1098 // Only do it for capacity spills not conflict spills. | |
| 1099 if( !deflrg._direct_conflict ) | |
| 1100 set_was_spilled(n); | |
| 1101 assert(!n->is_Phi(),"Cannot insert Phi into DEFS list"); | |
| 1102 // Grab UP info for DEF | |
| 1103 const RegMask &dmask = n->out_RegMask(); | |
| 1104 bool defup = dmask.is_UP(); | |
| 1105 // Only split at Def if this is a HRP block or bound (and spilled once) | |
| 1106 if( !n->rematerialize() && | |
| 1107 (((dmask.is_bound1() || dmask.is_bound2() || dmask.is_misaligned_Pair()) && | |
| 1108 (deflrg._direct_conflict || deflrg._must_spill)) || | |
| 1109 // Check for LRG being up in a register and we are inside a high | |
| 1110 // pressure area. Spill it down immediately. | |
| 1111 (defup && is_high_pressure(b,&deflrg,insidx))) ) { | |
| 1112 assert( !n->rematerialize(), "" ); | |
| 1113 assert( !n->is_SpillCopy(), "" ); | |
| 1114 // Do a split at the def site. | |
| 1115 maxlrg = split_DEF( n, b, insidx, maxlrg, Reachblock, debug_defs, splits, slidx ); | |
| 1116 // If it wasn't split bail | |
| 1117 if (!maxlrg) { | |
| 1118 return 0; | |
| 1119 } | |
| 1120 // Split DEF's Down | |
| 1121 UPblock[slidx] = 0; | |
| 1122 #ifndef PRODUCT | |
| 1123 // DEBUG | |
| 1124 if( trace_spilling() ) { | |
| 1125 tty->print("\nNew Split DOWN DEF of Spill Idx "); | |
| 1126 tty->print("%d, UP %d:\n",slidx,false); | |
| 1127 n->dump(); | |
| 1128 } | |
| 1129 #endif | |
| 1130 } | |
| 1131 else { // Neither bound nor HRP, must be LRP | |
| 1132 // otherwise, just record the def | |
| 1133 Reachblock[slidx] = n; | |
| 1134 // UP should come from the outRegmask() of the DEF | |
| 1135 UPblock[slidx] = defup; | |
| 1136 // Update debug list of reaching down definitions, kill if DEF is UP | |
| 1137 debug_defs[slidx] = defup ? NULL : n; | |
| 1138 #ifndef PRODUCT | |
| 1139 // DEBUG | |
| 1140 if( trace_spilling() ) { | |
| 1141 tty->print("\nNew DEF of Spill Idx "); | |
| 1142 tty->print("%d, UP %d:\n",slidx,defup); | |
| 1143 n->dump(); | |
| 1144 } | |
| 1145 #endif | |
| 1146 } // End else LRP | |
| 1147 } // End if spill def | |
| 1148 | |
| 1149 // ********** Split Left Over Mem-Mem Moves ********** | |
| 1150 // Check for mem-mem copies and split them now. Do not do this | |
| 1151 // to copies about to be spilled; they will be Split shortly. | |
| 1152 if( copyidx ) { | |
| 1153 Node *use = n->in(copyidx); | |
| 1154 uint useidx = Find_id(use); | |
| 1155 if( useidx < _maxlrg && // This is not a new split | |
| 1156 OptoReg::is_stack(deflrg.reg()) && | |
| 1157 deflrg.reg() < LRG::SPILL_REG ) { // And DEF is from stack | |
| 1158 LRG &uselrg = lrgs(useidx); | |
| 1159 if( OptoReg::is_stack(uselrg.reg()) && | |
| 1160 uselrg.reg() < LRG::SPILL_REG && // USE is from stack | |
| 1161 deflrg.reg() != uselrg.reg() ) { // Not trivially removed | |
| 1162 uint def_ideal_reg = Matcher::base2reg[n->bottom_type()->base()]; | |
| 1163 const RegMask &def_rm = *Matcher::idealreg2regmask[def_ideal_reg]; | |
| 1164 const RegMask &use_rm = n->in_RegMask(copyidx); | |
| 1165 if( def_rm.overlap(use_rm) && n->is_SpillCopy() ) { // Bug 4707800, 'n' may be a storeSSL | |
| 1166 if (C->check_node_count(NodeLimitFudgeFactor, out_of_nodes)) { // Check when generating nodes | |
| 1167 return 0; | |
| 1168 } | |
| 1169 Node *spill = new (C) MachSpillCopyNode(use,use_rm,def_rm); | |
| 1170 n->set_req(copyidx,spill); | |
| 1171 n->as_MachSpillCopy()->set_in_RegMask(def_rm); | |
| 1172 // Put the spill just before the copy | |
| 1173 insert_proj( b, insidx++, spill, maxlrg++ ); | |
| 1174 } | |
| 1175 } | |
| 1176 } | |
| 1177 } | |
| 1178 } // End For All Instructions in Block - Non-PHI Pass | |
| 1179 | |
| 1180 // Check if each LRG is live out of this block so as not to propagate | |
| 1181 // beyond the last use of a LRG. | |
| 1182 for( slidx = 0; slidx < spill_cnt; slidx++ ) { | |
| 1183 uint defidx = lidxs.at(slidx); | |
| 1184 IndexSet *liveout = _live->live(b); | |
| 1185 if( !liveout->member(defidx) ) { | |
| 1186 #ifdef ASSERT | |
| 1187 // The index defidx is not live. Check the liveout array to ensure that | |
| 1188 // it contains no members which compress to defidx. Finding such an | |
| 1189 // instance may be a case to add liveout adjustment in compress_uf_map(). | |
| 1190 // See 5063219. | |
| 1191 uint member; | |
| 1192 IndexSetIterator isi(liveout); | |
| 1193 while ((member = isi.next()) != 0) { | |
| 1194 assert(defidx != Find_const(member), "Live out member has not been compressed"); | |
| 1195 } | |
| 1196 #endif | |
| 1197 Reachblock[slidx] = NULL; | |
| 1198 } else { | |
| 1199 assert(Reachblock[slidx] != NULL,"No reaching definition for liveout value"); | |
| 1200 } | |
| 1201 } | |
| 1202 #ifndef PRODUCT | |
| 1203 if( trace_spilling() ) | |
| 1204 b->dump(); | |
| 1205 #endif | |
| 1206 } // End For All Blocks | |
| 1207 | |
| 1208 //----------PASS 2---------- | |
| 1209 // Reset all DEF live range numbers here | |
| 1210 for( insidx = 0; insidx < defs->size(); insidx++ ) { | |
| 1211 // Grab the def | |
| 1212 n1 = defs->at(insidx); | |
| 1213 // Set new lidx for DEF | |
| 1214 new_lrg(n1, maxlrg++); | |
| 1215 } | |
| 1216 //----------Phi Node Splitting---------- | |
| 1217 // Clean up a phi here, and assign a new live range number | |
| 1218 // Cycle through this block's predecessors, collecting Reaches | |
| 1219 // info for each spilled LRG and update edges. | |
| 1220 // Walk the phis list to patch inputs, split phis, and name phis | |
| 1221 for( insidx = 0; insidx < phis->size(); insidx++ ) { | |
| 1222 Node *phi = phis->at(insidx); | |
| 1223 assert(phi->is_Phi(),"This list must only contain Phi Nodes"); | |
| 1224 Block *b = _cfg._bbs[phi->_idx]; | |
| 1225 // Grab the live range number | |
| 1226 uint lidx = Find_id(phi); | |
| 1227 uint slidx = lrg2reach[lidx]; | |
| 1228 // Update node to lidx map | |
| 1229 new_lrg(phi, maxlrg++); | |
| 1230 // Get PASS1's up/down decision for the block. | |
| 1231 int phi_up = !!UP_entry[slidx]->test(b->_pre_order); | |
| 1232 | |
| 1233 // Force down if double-spilling live range | |
| 1234 if( lrgs(lidx)._was_spilled1 ) | |
| 1235 phi_up = false; | |
| 1236 | |
| 1237 // When splitting a Phi we an split it normal or "inverted". | |
| 1238 // An inverted split makes the splits target the Phi's UP/DOWN | |
| 1239 // sense inverted; then the Phi is followed by a final def-side | |
| 1240 // split to invert back. It changes which blocks the spill code | |
| 1241 // goes in. | |
| 1242 | |
| 1243 // Walk the predecessor blocks and assign the reaching def to the Phi. | |
| 1244 // Split Phi nodes by placing USE side splits wherever the reaching | |
| 1245 // DEF has the wrong UP/DOWN value. | |
| 1246 for( uint i = 1; i < b->num_preds(); i++ ) { | |
| 1247 // Get predecessor block pre-order number | |
| 1248 Block *pred = _cfg._bbs[b->pred(i)->_idx]; | |
| 1249 pidx = pred->_pre_order; | |
| 1250 // Grab reaching def | |
| 1251 Node *def = Reaches[pidx][slidx]; | |
| 1252 assert( def, "must have reaching def" ); | |
| 1253 // If input up/down sense and reg-pressure DISagree | |
| 1254 if( def->rematerialize() ) { | |
| 1255 def = split_Rematerialize( def, pred, pred->end_idx(), maxlrg, splits, slidx, lrg2reach, Reachblock, false ); | |
| 1256 if( !def ) return 0; // Bail out | |
| 1257 } | |
| 1258 // Update the Phi's input edge array | |
| 1259 phi->set_req(i,def); | |
| 1260 // Grab the UP/DOWN sense for the input | |
| 1261 u1 = UP[pidx][slidx]; | |
| 1262 if( u1 != (phi_up != 0)) { | |
| 1263 maxlrg = split_USE(def, b, phi, i, maxlrg, !u1, false, splits,slidx); | |
| 1264 // If it wasn't split bail | |
| 1265 if (!maxlrg) { | |
| 1266 return 0; | |
| 1267 } | |
| 1268 } | |
| 1269 } // End for all inputs to the Phi | |
| 1270 } // End for all Phi Nodes | |
| 1271 // Update _maxlrg to save Union asserts | |
| 1272 _maxlrg = maxlrg; | |
| 1273 | |
| 1274 | |
| 1275 //----------PASS 3---------- | |
| 1276 // Pass over all Phi's to union the live ranges | |
| 1277 for( insidx = 0; insidx < phis->size(); insidx++ ) { | |
| 1278 Node *phi = phis->at(insidx); | |
| 1279 assert(phi->is_Phi(),"This list must only contain Phi Nodes"); | |
| 1280 // Walk all inputs to Phi and Union input live range with Phi live range | |
| 1281 for( uint i = 1; i < phi->req(); i++ ) { | |
| 1282 // Grab the input node | |
| 1283 Node *n = phi->in(i); | |
| 1284 assert( n, "" ); | |
| 1285 uint lidx = Find(n); | |
| 1286 uint pidx = Find(phi); | |
| 1287 if( lidx < pidx ) | |
| 1288 Union(n, phi); | |
| 1289 else if( lidx > pidx ) | |
| 1290 Union(phi, n); | |
| 1291 } // End for all inputs to the Phi Node | |
| 1292 } // End for all Phi Nodes | |
| 1293 // Now union all two address instructions | |
| 1294 for( insidx = 0; insidx < defs->size(); insidx++ ) { | |
| 1295 // Grab the def | |
| 1296 n1 = defs->at(insidx); | |
| 1297 // Set new lidx for DEF & handle 2-addr instructions | |
| 1298 if( n1->is_Mach() && ((twoidx = n1->as_Mach()->two_adr()) != 0) ) { | |
| 1299 assert( Find(n1->in(twoidx)) < maxlrg,"Assigning bad live range index"); | |
| 1300 // Union the input and output live ranges | |
| 1301 uint lr1 = Find(n1); | |
| 1302 uint lr2 = Find(n1->in(twoidx)); | |
| 1303 if( lr1 < lr2 ) | |
| 1304 Union(n1, n1->in(twoidx)); | |
| 1305 else if( lr1 > lr2 ) | |
| 1306 Union(n1->in(twoidx), n1); | |
| 1307 } // End if two address | |
| 1308 } // End for all defs | |
| 1309 // DEBUG | |
| 1310 #ifdef ASSERT | |
| 1311 // Validate all live range index assignments | |
| 1312 for( bidx = 0; bidx < _cfg._num_blocks; bidx++ ) { | |
| 1313 b = _cfg._blocks[bidx]; | |
| 1314 for( insidx = 0; insidx <= b->end_idx(); insidx++ ) { | |
| 1315 Node *n = b->_nodes[insidx]; | |
| 1316 uint defidx = Find(n); | |
| 1317 assert(defidx < _maxlrg,"Bad live range index in Split"); | |
| 1318 assert(defidx < maxlrg,"Bad live range index in Split"); | |
| 1319 } | |
| 1320 } | |
| 1321 // Issue a warning if splitting made no progress | |
| 1322 int noprogress = 0; | |
| 1323 for( slidx = 0; slidx < spill_cnt; slidx++ ) { | |
| 1324 if( PrintOpto && WizardMode && splits.at(slidx) == 0 ) { | |
| 1325 tty->print_cr("Failed to split live range %d", lidxs.at(slidx)); | |
| 1326 //BREAKPOINT; | |
| 1327 } | |
| 1328 else { | |
| 1329 noprogress++; | |
| 1330 } | |
| 1331 } | |
| 1332 if(!noprogress) { | |
| 1333 tty->print_cr("Failed to make progress in Split"); | |
| 1334 //BREAKPOINT; | |
| 1335 } | |
| 1336 #endif | |
| 1337 // Return updated count of live ranges | |
| 1338 return maxlrg; | |
| 1339 } |