LiveInterval.cpp revision 41169551d59e9aee3d9dcd043013d65ee6e33759
1//===-- LiveInterval.cpp - Live Interval Representation -------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LiveRange and LiveInterval classes. Given some 11// numbering of each the machine instructions an interval [i, j) is said to be a 12// live interval for register v if there is no instruction with number j' > j 13// such that v is live at j' abd there is no instruction with number i' < i such 14// that v is live at i'. In this implementation intervals can have holes, 15// i.e. an interval might look like [1,20), [50,65), [1000,1001). Each 16// individual range is represented as an instance of LiveRange, and the whole 17// interval is represented as an instance of LiveInterval. 18// 19//===----------------------------------------------------------------------===// 20 21#include "llvm/CodeGen/LiveInterval.h" 22#include "llvm/CodeGen/MachineRegisterInfo.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallSet.h" 25#include "llvm/ADT/STLExtras.h" 26#include "llvm/Support/Streams.h" 27#include "llvm/Target/TargetRegisterInfo.h" 28#include <algorithm> 29#include <ostream> 30using namespace llvm; 31 32// An example for liveAt(): 33// 34// this = [1,4), liveAt(0) will return false. The instruction defining this 35// spans slots [0,3]. The interval belongs to an spilled definition of the 36// variable it represents. This is because slot 1 is used (def slot) and spans 37// up to slot 3 (store slot). 38// 39bool LiveInterval::liveAt(unsigned I) const { 40 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 41 42 if (r == ranges.begin()) 43 return false; 44 45 --r; 46 return r->contains(I); 47} 48 49// liveBeforeAndAt - Check if the interval is live at the index and the index 50// just before it. If index is liveAt, check if it starts a new live range. 51// If it does, then check if the previous live range ends at index-1. 52bool LiveInterval::liveBeforeAndAt(unsigned I) const { 53 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 54 55 if (r == ranges.begin()) 56 return false; 57 58 --r; 59 if (!r->contains(I)) 60 return false; 61 if (I != r->start) 62 return true; 63 // I is the start of a live range. Check if the previous live range ends 64 // at I-1. 65 if (r == ranges.begin()) 66 return false; 67 return r->end == I; 68} 69 70// overlaps - Return true if the intersection of the two live intervals is 71// not empty. 72// 73// An example for overlaps(): 74// 75// 0: A = ... 76// 4: B = ... 77// 8: C = A + B ;; last use of A 78// 79// The live intervals should look like: 80// 81// A = [3, 11) 82// B = [7, x) 83// C = [11, y) 84// 85// A->overlaps(C) should return false since we want to be able to join 86// A and C. 87// 88bool LiveInterval::overlapsFrom(const LiveInterval& other, 89 const_iterator StartPos) const { 90 const_iterator i = begin(); 91 const_iterator ie = end(); 92 const_iterator j = StartPos; 93 const_iterator je = other.end(); 94 95 assert((StartPos->start <= i->start || StartPos == other.begin()) && 96 StartPos != other.end() && "Bogus start position hint!"); 97 98 if (i->start < j->start) { 99 i = std::upper_bound(i, ie, j->start); 100 if (i != ranges.begin()) --i; 101 } else if (j->start < i->start) { 102 ++StartPos; 103 if (StartPos != other.end() && StartPos->start <= i->start) { 104 assert(StartPos < other.end() && i < end()); 105 j = std::upper_bound(j, je, i->start); 106 if (j != other.ranges.begin()) --j; 107 } 108 } else { 109 return true; 110 } 111 112 if (j == je) return false; 113 114 while (i != ie) { 115 if (i->start > j->start) { 116 std::swap(i, j); 117 std::swap(ie, je); 118 } 119 120 if (i->end > j->start) 121 return true; 122 ++i; 123 } 124 125 return false; 126} 127 128/// overlaps - Return true if the live interval overlaps a range specified 129/// by [Start, End). 130bool LiveInterval::overlaps(unsigned Start, unsigned End) const { 131 assert(Start < End && "Invalid range"); 132 const_iterator I = begin(); 133 const_iterator E = end(); 134 const_iterator si = std::upper_bound(I, E, Start); 135 const_iterator ei = std::upper_bound(I, E, End); 136 if (si != ei) 137 return true; 138 if (si == I) 139 return false; 140 --si; 141 return si->contains(Start); 142} 143 144/// extendIntervalEndTo - This method is used when we want to extend the range 145/// specified by I to end at the specified endpoint. To do this, we should 146/// merge and eliminate all ranges that this will overlap with. The iterator is 147/// not invalidated. 148void LiveInterval::extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd) { 149 assert(I != ranges.end() && "Not a valid interval!"); 150 VNInfo *ValNo = I->valno; 151 unsigned OldEnd = I->end; 152 153 // Search for the first interval that we can't merge with. 154 Ranges::iterator MergeTo = next(I); 155 for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) { 156 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 157 } 158 159 // If NewEnd was in the middle of an interval, make sure to get its endpoint. 160 I->end = std::max(NewEnd, prior(MergeTo)->end); 161 162 // Erase any dead ranges. 163 ranges.erase(next(I), MergeTo); 164 165 // Update kill info. 166 removeKills(ValNo, OldEnd, I->end-1); 167 168 // If the newly formed range now touches the range after it and if they have 169 // the same value number, merge the two ranges into one range. 170 Ranges::iterator Next = next(I); 171 if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) { 172 I->end = Next->end; 173 ranges.erase(Next); 174 } 175} 176 177 178/// extendIntervalStartTo - This method is used when we want to extend the range 179/// specified by I to start at the specified endpoint. To do this, we should 180/// merge and eliminate all ranges that this will overlap with. 181LiveInterval::Ranges::iterator 182LiveInterval::extendIntervalStartTo(Ranges::iterator I, unsigned NewStart) { 183 assert(I != ranges.end() && "Not a valid interval!"); 184 VNInfo *ValNo = I->valno; 185 186 // Search for the first interval that we can't merge with. 187 Ranges::iterator MergeTo = I; 188 do { 189 if (MergeTo == ranges.begin()) { 190 I->start = NewStart; 191 ranges.erase(MergeTo, I); 192 return I; 193 } 194 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 195 --MergeTo; 196 } while (NewStart <= MergeTo->start); 197 198 // If we start in the middle of another interval, just delete a range and 199 // extend that interval. 200 if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) { 201 MergeTo->end = I->end; 202 } else { 203 // Otherwise, extend the interval right after. 204 ++MergeTo; 205 MergeTo->start = NewStart; 206 MergeTo->end = I->end; 207 } 208 209 ranges.erase(next(MergeTo), next(I)); 210 return MergeTo; 211} 212 213LiveInterval::iterator 214LiveInterval::addRangeFrom(LiveRange LR, iterator From) { 215 unsigned Start = LR.start, End = LR.end; 216 iterator it = std::upper_bound(From, ranges.end(), Start); 217 218 // If the inserted interval starts in the middle or right at the end of 219 // another interval, just extend that interval to contain the range of LR. 220 if (it != ranges.begin()) { 221 iterator B = prior(it); 222 if (LR.valno == B->valno) { 223 if (B->start <= Start && B->end >= Start) { 224 extendIntervalEndTo(B, End); 225 return B; 226 } 227 } else { 228 // Check to make sure that we are not overlapping two live ranges with 229 // different valno's. 230 assert(B->end <= Start && 231 "Cannot overlap two LiveRanges with differing ValID's" 232 " (did you def the same reg twice in a MachineInstr?)"); 233 } 234 } 235 236 // Otherwise, if this range ends in the middle of, or right next to, another 237 // interval, merge it into that interval. 238 if (it != ranges.end()) { 239 if (LR.valno == it->valno) { 240 if (it->start <= End) { 241 it = extendIntervalStartTo(it, Start); 242 243 // If LR is a complete superset of an interval, we may need to grow its 244 // endpoint as well. 245 if (End > it->end) 246 extendIntervalEndTo(it, End); 247 else if (End < it->end) 248 // Overlapping intervals, there might have been a kill here. 249 removeKill(it->valno, End); 250 return it; 251 } 252 } else { 253 // Check to make sure that we are not overlapping two live ranges with 254 // different valno's. 255 assert(it->start >= End && 256 "Cannot overlap two LiveRanges with differing ValID's"); 257 } 258 } 259 260 // Otherwise, this is just a new range that doesn't interact with anything. 261 // Insert it. 262 return ranges.insert(it, LR); 263} 264 265/// isInOneLiveRange - Return true if the range specified is entirely in the 266/// a single LiveRange of the live interval. 267bool LiveInterval::isInOneLiveRange(unsigned Start, unsigned End) { 268 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 269 if (I == ranges.begin()) 270 return false; 271 --I; 272 return I->contains(Start) && I->contains(End-1); 273} 274 275 276/// removeRange - Remove the specified range from this interval. Note that 277/// the range must be in a single LiveRange in its entirety. 278void LiveInterval::removeRange(unsigned Start, unsigned End, 279 bool RemoveDeadValNo) { 280 // Find the LiveRange containing this span. 281 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 282 assert(I != ranges.begin() && "Range is not in interval!"); 283 --I; 284 assert(I->contains(Start) && I->contains(End-1) && 285 "Range is not entirely in interval!"); 286 287 // If the span we are removing is at the start of the LiveRange, adjust it. 288 VNInfo *ValNo = I->valno; 289 if (I->start == Start) { 290 if (I->end == End) { 291 removeKills(I->valno, Start, End); 292 if (RemoveDeadValNo) { 293 // Check if val# is dead. 294 bool isDead = true; 295 for (const_iterator II = begin(), EE = end(); II != EE; ++II) 296 if (II != I && II->valno == ValNo) { 297 isDead = false; 298 break; 299 } 300 if (isDead) { 301 // Now that ValNo is dead, remove it. If it is the largest value 302 // number, just nuke it (and any other deleted values neighboring it), 303 // otherwise mark it as ~1U so it can be nuked later. 304 if (ValNo->id == getNumValNums()-1) { 305 do { 306 VNInfo *VNI = valnos.back(); 307 valnos.pop_back(); 308 VNI->~VNInfo(); 309 } while (!valnos.empty() && valnos.back()->def == ~1U); 310 } else { 311 ValNo->def = ~1U; 312 } 313 } 314 } 315 316 ranges.erase(I); // Removed the whole LiveRange. 317 } else 318 I->start = End; 319 return; 320 } 321 322 // Otherwise if the span we are removing is at the end of the LiveRange, 323 // adjust the other way. 324 if (I->end == End) { 325 removeKills(ValNo, Start, End); 326 I->end = Start; 327 return; 328 } 329 330 // Otherwise, we are splitting the LiveRange into two pieces. 331 unsigned OldEnd = I->end; 332 I->end = Start; // Trim the old interval. 333 334 // Insert the new one. 335 ranges.insert(next(I), LiveRange(End, OldEnd, ValNo)); 336} 337 338/// removeValNo - Remove all the ranges defined by the specified value#. 339/// Also remove the value# from value# list. 340void LiveInterval::removeValNo(VNInfo *ValNo) { 341 if (empty()) return; 342 Ranges::iterator I = ranges.end(); 343 Ranges::iterator E = ranges.begin(); 344 do { 345 --I; 346 if (I->valno == ValNo) 347 ranges.erase(I); 348 } while (I != E); 349 // Now that ValNo is dead, remove it. If it is the largest value 350 // number, just nuke it (and any other deleted values neighboring it), 351 // otherwise mark it as ~1U so it can be nuked later. 352 if (ValNo->id == getNumValNums()-1) { 353 do { 354 VNInfo *VNI = valnos.back(); 355 valnos.pop_back(); 356 VNI->~VNInfo(); 357 } while (!valnos.empty() && valnos.back()->def == ~1U); 358 } else { 359 ValNo->def = ~1U; 360 } 361} 362 363/// scaleNumbering - Renumber VNI and ranges to provide gaps for new 364/// instructions. 365void LiveInterval::scaleNumbering(unsigned factor) { 366 // Scale ranges. 367 for (iterator RI = begin(), RE = end(); RI != RE; ++RI) { 368 RI->start = InstrSlots::scale(RI->start, factor); 369 RI->end = InstrSlots::scale(RI->end, factor); 370 } 371 372 // Scale VNI info. 373 for (vni_iterator VNI = vni_begin(), VNIE = vni_end(); VNI != VNIE; ++VNI) { 374 VNInfo *vni = *VNI; 375 if (vni->def != ~0U && vni->def != ~1U) { 376 vni->def = InstrSlots::scale(vni->def, factor); 377 } 378 379 for (unsigned i = 0; i < vni->kills.size(); ++i) { 380 if (vni->kills[i] != 0) 381 vni->kills[i] = InstrSlots::scale(vni->kills[i], factor); 382 } 383 } 384} 385 386/// getLiveRangeContaining - Return the live range that contains the 387/// specified index, or null if there is none. 388LiveInterval::const_iterator 389LiveInterval::FindLiveRangeContaining(unsigned Idx) const { 390 const_iterator It = std::upper_bound(begin(), end(), Idx); 391 if (It != ranges.begin()) { 392 --It; 393 if (It->contains(Idx)) 394 return It; 395 } 396 397 return end(); 398} 399 400LiveInterval::iterator 401LiveInterval::FindLiveRangeContaining(unsigned Idx) { 402 iterator It = std::upper_bound(begin(), end(), Idx); 403 if (It != begin()) { 404 --It; 405 if (It->contains(Idx)) 406 return It; 407 } 408 409 return end(); 410} 411 412/// findDefinedVNInfo - Find the VNInfo that's defined at the specified index 413/// (register interval) or defined by the specified register (stack inteval). 414VNInfo *LiveInterval::findDefinedVNInfo(unsigned DefIdxOrReg) const { 415 VNInfo *VNI = NULL; 416 for (LiveInterval::const_vni_iterator i = vni_begin(), e = vni_end(); 417 i != e; ++i) 418 if ((*i)->def == DefIdxOrReg) { 419 VNI = *i; 420 break; 421 } 422 return VNI; 423} 424 425/// join - Join two live intervals (this, and other) together. This applies 426/// mappings to the value numbers in the LHS/RHS intervals as specified. If 427/// the intervals are not joinable, this aborts. 428void LiveInterval::join(LiveInterval &Other, const int *LHSValNoAssignments, 429 const int *RHSValNoAssignments, 430 SmallVector<VNInfo*, 16> &NewVNInfo, 431 MachineRegisterInfo *MRI) { 432 // Determine if any of our live range values are mapped. This is uncommon, so 433 // we want to avoid the interval scan if not. 434 bool MustMapCurValNos = false; 435 unsigned NumVals = getNumValNums(); 436 unsigned NumNewVals = NewVNInfo.size(); 437 for (unsigned i = 0; i != NumVals; ++i) { 438 unsigned LHSValID = LHSValNoAssignments[i]; 439 if (i != LHSValID || 440 (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) 441 MustMapCurValNos = true; 442 } 443 444 // If we have to apply a mapping to our base interval assignment, rewrite it 445 // now. 446 if (MustMapCurValNos) { 447 // Map the first live range. 448 iterator OutIt = begin(); 449 OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]]; 450 ++OutIt; 451 for (iterator I = OutIt, E = end(); I != E; ++I) { 452 OutIt->valno = NewVNInfo[LHSValNoAssignments[I->valno->id]]; 453 454 // If this live range has the same value # as its immediate predecessor, 455 // and if they are neighbors, remove one LiveRange. This happens when we 456 // have [0,3:0)[4,7:1) and map 0/1 onto the same value #. 457 if (OutIt->valno == (OutIt-1)->valno && (OutIt-1)->end == OutIt->start) { 458 (OutIt-1)->end = OutIt->end; 459 } else { 460 if (I != OutIt) { 461 OutIt->start = I->start; 462 OutIt->end = I->end; 463 } 464 465 // Didn't merge, on to the next one. 466 ++OutIt; 467 } 468 } 469 470 // If we merge some live ranges, chop off the end. 471 ranges.erase(OutIt, end()); 472 } 473 474 // Remember assignements because val# ids are changing. 475 SmallVector<unsigned, 16> OtherAssignments; 476 for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) 477 OtherAssignments.push_back(RHSValNoAssignments[I->valno->id]); 478 479 // Update val# info. Renumber them and make sure they all belong to this 480 // LiveInterval now. Also remove dead val#'s. 481 unsigned NumValNos = 0; 482 for (unsigned i = 0; i < NumNewVals; ++i) { 483 VNInfo *VNI = NewVNInfo[i]; 484 if (VNI) { 485 if (NumValNos >= NumVals) 486 valnos.push_back(VNI); 487 else 488 valnos[NumValNos] = VNI; 489 VNI->id = NumValNos++; // Renumber val#. 490 } 491 } 492 if (NumNewVals < NumVals) 493 valnos.resize(NumNewVals); // shrinkify 494 495 // Okay, now insert the RHS live ranges into the LHS. 496 iterator InsertPos = begin(); 497 unsigned RangeNo = 0; 498 for (iterator I = Other.begin(), E = Other.end(); I != E; ++I, ++RangeNo) { 499 // Map the valno in the other live range to the current live range. 500 I->valno = NewVNInfo[OtherAssignments[RangeNo]]; 501 assert(I->valno && "Adding a dead range?"); 502 InsertPos = addRangeFrom(*I, InsertPos); 503 } 504 505 weight += Other.weight; 506 507 // Update regalloc hint if currently there isn't one. 508 if (TargetRegisterInfo::isVirtualRegister(reg) && 509 TargetRegisterInfo::isVirtualRegister(Other.reg)) { 510 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(reg); 511 if (Hint.first == 0 && Hint.second == 0) { 512 std::pair<unsigned, unsigned> OtherHint = 513 MRI->getRegAllocationHint(Other.reg); 514 if (OtherHint.first || OtherHint.second) 515 MRI->setRegAllocationHint(reg, OtherHint.first, OtherHint.second); 516 } 517 } 518} 519 520/// MergeRangesInAsValue - Merge all of the intervals in RHS into this live 521/// interval as the specified value number. The LiveRanges in RHS are 522/// allowed to overlap with LiveRanges in the current interval, but only if 523/// the overlapping LiveRanges have the specified value number. 524void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS, 525 VNInfo *LHSValNo) { 526 // TODO: Make this more efficient. 527 iterator InsertPos = begin(); 528 for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { 529 // Map the valno in the other live range to the current live range. 530 LiveRange Tmp = *I; 531 Tmp.valno = LHSValNo; 532 InsertPos = addRangeFrom(Tmp, InsertPos); 533 } 534} 535 536 537/// MergeValueInAsValue - Merge all of the live ranges of a specific val# 538/// in RHS into this live interval as the specified value number. 539/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the 540/// current interval, it will replace the value numbers of the overlaped 541/// live ranges with the specified value number. 542void LiveInterval::MergeValueInAsValue(const LiveInterval &RHS, 543 const VNInfo *RHSValNo, VNInfo *LHSValNo) { 544 SmallVector<VNInfo*, 4> ReplacedValNos; 545 iterator IP = begin(); 546 for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { 547 if (I->valno != RHSValNo) 548 continue; 549 unsigned Start = I->start, End = I->end; 550 IP = std::upper_bound(IP, end(), Start); 551 // If the start of this range overlaps with an existing liverange, trim it. 552 if (IP != begin() && IP[-1].end > Start) { 553 if (IP[-1].valno != LHSValNo) { 554 ReplacedValNos.push_back(IP[-1].valno); 555 IP[-1].valno = LHSValNo; // Update val#. 556 } 557 Start = IP[-1].end; 558 // Trimmed away the whole range? 559 if (Start >= End) continue; 560 } 561 // If the end of this range overlaps with an existing liverange, trim it. 562 if (IP != end() && End > IP->start) { 563 if (IP->valno != LHSValNo) { 564 ReplacedValNos.push_back(IP->valno); 565 IP->valno = LHSValNo; // Update val#. 566 } 567 End = IP->start; 568 // If this trimmed away the whole range, ignore it. 569 if (Start == End) continue; 570 } 571 572 // Map the valno in the other live range to the current live range. 573 IP = addRangeFrom(LiveRange(Start, End, LHSValNo), IP); 574 } 575 576 577 SmallSet<VNInfo*, 4> Seen; 578 for (unsigned i = 0, e = ReplacedValNos.size(); i != e; ++i) { 579 VNInfo *V1 = ReplacedValNos[i]; 580 if (Seen.insert(V1)) { 581 bool isDead = true; 582 for (const_iterator I = begin(), E = end(); I != E; ++I) 583 if (I->valno == V1) { 584 isDead = false; 585 break; 586 } 587 if (isDead) { 588 // Now that V1 is dead, remove it. If it is the largest value number, 589 // just nuke it (and any other deleted values neighboring it), otherwise 590 // mark it as ~1U so it can be nuked later. 591 if (V1->id == getNumValNums()-1) { 592 do { 593 VNInfo *VNI = valnos.back(); 594 valnos.pop_back(); 595 VNI->~VNInfo(); 596 } while (!valnos.empty() && valnos.back()->def == ~1U); 597 } else { 598 V1->def = ~1U; 599 } 600 } 601 } 602 } 603} 604 605 606/// MergeInClobberRanges - For any live ranges that are not defined in the 607/// current interval, but are defined in the Clobbers interval, mark them 608/// used with an unknown definition value. 609void LiveInterval::MergeInClobberRanges(const LiveInterval &Clobbers, 610 BumpPtrAllocator &VNInfoAllocator) { 611 if (Clobbers.empty()) return; 612 613 DenseMap<VNInfo*, VNInfo*> ValNoMaps; 614 VNInfo *UnusedValNo = 0; 615 iterator IP = begin(); 616 for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) { 617 // For every val# in the Clobbers interval, create a new "unknown" val#. 618 VNInfo *ClobberValNo = 0; 619 DenseMap<VNInfo*, VNInfo*>::iterator VI = ValNoMaps.find(I->valno); 620 if (VI != ValNoMaps.end()) 621 ClobberValNo = VI->second; 622 else if (UnusedValNo) 623 ClobberValNo = UnusedValNo; 624 else { 625 UnusedValNo = ClobberValNo = getNextValue(~0U, 0, VNInfoAllocator); 626 ValNoMaps.insert(std::make_pair(I->valno, ClobberValNo)); 627 } 628 629 bool Done = false; 630 unsigned Start = I->start, End = I->end; 631 // If a clobber range starts before an existing range and ends after 632 // it, the clobber range will need to be split into multiple ranges. 633 // Loop until the entire clobber range is handled. 634 while (!Done) { 635 Done = true; 636 IP = std::upper_bound(IP, end(), Start); 637 unsigned SubRangeStart = Start; 638 unsigned SubRangeEnd = End; 639 640 // If the start of this range overlaps with an existing liverange, trim it. 641 if (IP != begin() && IP[-1].end > SubRangeStart) { 642 SubRangeStart = IP[-1].end; 643 // Trimmed away the whole range? 644 if (SubRangeStart >= SubRangeEnd) continue; 645 } 646 // If the end of this range overlaps with an existing liverange, trim it. 647 if (IP != end() && SubRangeEnd > IP->start) { 648 // If the clobber live range extends beyond the existing live range, 649 // it'll need at least another live range, so set the flag to keep 650 // iterating. 651 if (SubRangeEnd > IP->end) { 652 Start = IP->end; 653 Done = false; 654 } 655 SubRangeEnd = IP->start; 656 // If this trimmed away the whole range, ignore it. 657 if (SubRangeStart == SubRangeEnd) continue; 658 } 659 660 // Insert the clobber interval. 661 IP = addRangeFrom(LiveRange(SubRangeStart, SubRangeEnd, ClobberValNo), 662 IP); 663 UnusedValNo = 0; 664 } 665 } 666 667 if (UnusedValNo) { 668 // Delete the last unused val#. 669 valnos.pop_back(); 670 UnusedValNo->~VNInfo(); 671 } 672} 673 674void LiveInterval::MergeInClobberRange(unsigned Start, unsigned End, 675 BumpPtrAllocator &VNInfoAllocator) { 676 // Find a value # to use for the clobber ranges. If there is already a value# 677 // for unknown values, use it. 678 VNInfo *ClobberValNo = getNextValue(~0U, 0, VNInfoAllocator); 679 680 iterator IP = begin(); 681 IP = std::upper_bound(IP, end(), Start); 682 683 // If the start of this range overlaps with an existing liverange, trim it. 684 if (IP != begin() && IP[-1].end > Start) { 685 Start = IP[-1].end; 686 // Trimmed away the whole range? 687 if (Start >= End) return; 688 } 689 // If the end of this range overlaps with an existing liverange, trim it. 690 if (IP != end() && End > IP->start) { 691 End = IP->start; 692 // If this trimmed away the whole range, ignore it. 693 if (Start == End) return; 694 } 695 696 // Insert the clobber interval. 697 addRangeFrom(LiveRange(Start, End, ClobberValNo), IP); 698} 699 700/// MergeValueNumberInto - This method is called when two value nubmers 701/// are found to be equivalent. This eliminates V1, replacing all 702/// LiveRanges with the V1 value number with the V2 value number. This can 703/// cause merging of V1/V2 values numbers and compaction of the value space. 704VNInfo* LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) { 705 assert(V1 != V2 && "Identical value#'s are always equivalent!"); 706 707 // This code actually merges the (numerically) larger value number into the 708 // smaller value number, which is likely to allow us to compactify the value 709 // space. The only thing we have to be careful of is to preserve the 710 // instruction that defines the result value. 711 712 // Make sure V2 is smaller than V1. 713 if (V1->id < V2->id) { 714 copyValNumInfo(V1, V2); 715 std::swap(V1, V2); 716 } 717 718 // Merge V1 live ranges into V2. 719 for (iterator I = begin(); I != end(); ) { 720 iterator LR = I++; 721 if (LR->valno != V1) continue; // Not a V1 LiveRange. 722 723 // Okay, we found a V1 live range. If it had a previous, touching, V2 live 724 // range, extend it. 725 if (LR != begin()) { 726 iterator Prev = LR-1; 727 if (Prev->valno == V2 && Prev->end == LR->start) { 728 Prev->end = LR->end; 729 730 // Erase this live-range. 731 ranges.erase(LR); 732 I = Prev+1; 733 LR = Prev; 734 } 735 } 736 737 // Okay, now we have a V1 or V2 live range that is maximally merged forward. 738 // Ensure that it is a V2 live-range. 739 LR->valno = V2; 740 741 // If we can merge it into later V2 live ranges, do so now. We ignore any 742 // following V1 live ranges, as they will be merged in subsequent iterations 743 // of the loop. 744 if (I != end()) { 745 if (I->start == LR->end && I->valno == V2) { 746 LR->end = I->end; 747 ranges.erase(I); 748 I = LR+1; 749 } 750 } 751 } 752 753 // Now that V1 is dead, remove it. If it is the largest value number, just 754 // nuke it (and any other deleted values neighboring it), otherwise mark it as 755 // ~1U so it can be nuked later. 756 if (V1->id == getNumValNums()-1) { 757 do { 758 VNInfo *VNI = valnos.back(); 759 valnos.pop_back(); 760 VNI->~VNInfo(); 761 } while (valnos.back()->def == ~1U); 762 } else { 763 V1->def = ~1U; 764 } 765 766 return V2; 767} 768 769void LiveInterval::Copy(const LiveInterval &RHS, 770 MachineRegisterInfo *MRI, 771 BumpPtrAllocator &VNInfoAllocator) { 772 ranges.clear(); 773 valnos.clear(); 774 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(RHS.reg); 775 MRI->setRegAllocationHint(reg, Hint.first, Hint.second); 776 777 weight = RHS.weight; 778 for (unsigned i = 0, e = RHS.getNumValNums(); i != e; ++i) { 779 const VNInfo *VNI = RHS.getValNumInfo(i); 780 VNInfo *NewVNI = getNextValue(~0U, 0, VNInfoAllocator); 781 copyValNumInfo(NewVNI, VNI); 782 } 783 for (unsigned i = 0, e = RHS.ranges.size(); i != e; ++i) { 784 const LiveRange &LR = RHS.ranges[i]; 785 addRange(LiveRange(LR.start, LR.end, getValNumInfo(LR.valno->id))); 786 } 787} 788 789unsigned LiveInterval::getSize() const { 790 unsigned Sum = 0; 791 for (const_iterator I = begin(), E = end(); I != E; ++I) 792 Sum += I->end - I->start; 793 return Sum; 794} 795 796std::ostream& llvm::operator<<(std::ostream& os, const LiveRange &LR) { 797 return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")"; 798} 799 800void LiveRange::dump() const { 801 cerr << *this << "\n"; 802} 803 804void LiveInterval::print(std::ostream &OS, 805 const TargetRegisterInfo *TRI) const { 806 if (isStackSlot()) 807 OS << "SS#" << getStackSlotIndex(); 808 else if (TRI && TargetRegisterInfo::isPhysicalRegister(reg)) 809 OS << TRI->getName(reg); 810 else 811 OS << "%reg" << reg; 812 813 OS << ',' << weight; 814 815 if (empty()) 816 OS << " EMPTY"; 817 else { 818 OS << " = "; 819 for (LiveInterval::Ranges::const_iterator I = ranges.begin(), 820 E = ranges.end(); I != E; ++I) 821 OS << *I; 822 } 823 824 // Print value number info. 825 if (getNumValNums()) { 826 OS << " "; 827 unsigned vnum = 0; 828 for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e; 829 ++i, ++vnum) { 830 const VNInfo *vni = *i; 831 if (vnum) OS << " "; 832 OS << vnum << "@"; 833 if (vni->def == ~1U) { 834 OS << "x"; 835 } else { 836 if (vni->def == ~0U) 837 OS << "?"; 838 else 839 OS << vni->def; 840 unsigned ee = vni->kills.size(); 841 if (ee || vni->hasPHIKill) { 842 OS << "-("; 843 for (unsigned j = 0; j != ee; ++j) { 844 OS << vni->kills[j]; 845 if (j != ee-1) 846 OS << " "; 847 } 848 if (vni->hasPHIKill) { 849 if (ee) 850 OS << " "; 851 OS << "phi"; 852 } 853 OS << ")"; 854 } 855 } 856 } 857 } 858} 859 860void LiveInterval::dump() const { 861 cerr << *this << "\n"; 862} 863 864 865void LiveRange::print(std::ostream &os) const { 866 os << *this; 867} 868