LiveInterval.cpp revision c02497f5bae87e71fd5617db5751cb0b3a14bbed
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/raw_ostream.h" 27#include "llvm/Target/TargetRegisterInfo.h" 28#include <algorithm> 29using namespace llvm; 30 31// An example for liveAt(): 32// 33// this = [1,4), liveAt(0) will return false. The instruction defining this 34// spans slots [0,3]. The interval belongs to an spilled definition of the 35// variable it represents. This is because slot 1 is used (def slot) and spans 36// up to slot 3 (store slot). 37// 38bool LiveInterval::liveAt(unsigned I) const { 39 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 40 41 if (r == ranges.begin()) 42 return false; 43 44 --r; 45 return r->contains(I); 46} 47 48// liveBeforeAndAt - Check if the interval is live at the index and the index 49// just before it. If index is liveAt, check if it starts a new live range. 50// If it does, then check if the previous live range ends at index-1. 51bool LiveInterval::liveBeforeAndAt(unsigned I) const { 52 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 53 54 if (r == ranges.begin()) 55 return false; 56 57 --r; 58 if (!r->contains(I)) 59 return false; 60 if (I != r->start) 61 return true; 62 // I is the start of a live range. Check if the previous live range ends 63 // at I-1. 64 if (r == ranges.begin()) 65 return false; 66 return r->end == I; 67} 68 69// overlaps - Return true if the intersection of the two live intervals is 70// not empty. 71// 72// An example for overlaps(): 73// 74// 0: A = ... 75// 4: B = ... 76// 8: C = A + B ;; last use of A 77// 78// The live intervals should look like: 79// 80// A = [3, 11) 81// B = [7, x) 82// C = [11, y) 83// 84// A->overlaps(C) should return false since we want to be able to join 85// A and C. 86// 87bool LiveInterval::overlapsFrom(const LiveInterval& other, 88 const_iterator StartPos) const { 89 const_iterator i = begin(); 90 const_iterator ie = end(); 91 const_iterator j = StartPos; 92 const_iterator je = other.end(); 93 94 assert((StartPos->start <= i->start || StartPos == other.begin()) && 95 StartPos != other.end() && "Bogus start position hint!"); 96 97 if (i->start < j->start) { 98 i = std::upper_bound(i, ie, j->start); 99 if (i != ranges.begin()) --i; 100 } else if (j->start < i->start) { 101 ++StartPos; 102 if (StartPos != other.end() && StartPos->start <= i->start) { 103 assert(StartPos < other.end() && i < end()); 104 j = std::upper_bound(j, je, i->start); 105 if (j != other.ranges.begin()) --j; 106 } 107 } else { 108 return true; 109 } 110 111 if (j == je) return false; 112 113 while (i != ie) { 114 if (i->start > j->start) { 115 std::swap(i, j); 116 std::swap(ie, je); 117 } 118 119 if (i->end > j->start) 120 return true; 121 ++i; 122 } 123 124 return false; 125} 126 127/// overlaps - Return true if the live interval overlaps a range specified 128/// by [Start, End). 129bool LiveInterval::overlaps(unsigned Start, unsigned End) const { 130 assert(Start < End && "Invalid range"); 131 const_iterator I = begin(); 132 const_iterator E = end(); 133 const_iterator si = std::upper_bound(I, E, Start); 134 const_iterator ei = std::upper_bound(I, E, End); 135 if (si != ei) 136 return true; 137 if (si == I) 138 return false; 139 --si; 140 return si->contains(Start); 141} 142 143/// extendIntervalEndTo - This method is used when we want to extend the range 144/// specified by I to end at the specified endpoint. To do this, we should 145/// merge and eliminate all ranges that this will overlap with. The iterator is 146/// not invalidated. 147void LiveInterval::extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd) { 148 assert(I != ranges.end() && "Not a valid interval!"); 149 VNInfo *ValNo = I->valno; 150 unsigned OldEnd = I->end; 151 152 // Search for the first interval that we can't merge with. 153 Ranges::iterator MergeTo = next(I); 154 for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) { 155 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 156 } 157 158 // If NewEnd was in the middle of an interval, make sure to get its endpoint. 159 I->end = std::max(NewEnd, prior(MergeTo)->end); 160 161 // Erase any dead ranges. 162 ranges.erase(next(I), MergeTo); 163 164 // Update kill info. 165 removeKills(ValNo, OldEnd, I->end-1); 166 167 // If the newly formed range now touches the range after it and if they have 168 // the same value number, merge the two ranges into one range. 169 Ranges::iterator Next = next(I); 170 if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) { 171 I->end = Next->end; 172 ranges.erase(Next); 173 } 174} 175 176 177/// extendIntervalStartTo - This method is used when we want to extend the range 178/// specified by I to start at the specified endpoint. To do this, we should 179/// merge and eliminate all ranges that this will overlap with. 180LiveInterval::Ranges::iterator 181LiveInterval::extendIntervalStartTo(Ranges::iterator I, unsigned NewStart) { 182 assert(I != ranges.end() && "Not a valid interval!"); 183 VNInfo *ValNo = I->valno; 184 185 // Search for the first interval that we can't merge with. 186 Ranges::iterator MergeTo = I; 187 do { 188 if (MergeTo == ranges.begin()) { 189 I->start = NewStart; 190 ranges.erase(MergeTo, I); 191 return I; 192 } 193 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 194 --MergeTo; 195 } while (NewStart <= MergeTo->start); 196 197 // If we start in the middle of another interval, just delete a range and 198 // extend that interval. 199 if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) { 200 MergeTo->end = I->end; 201 } else { 202 // Otherwise, extend the interval right after. 203 ++MergeTo; 204 MergeTo->start = NewStart; 205 MergeTo->end = I->end; 206 } 207 208 ranges.erase(next(MergeTo), next(I)); 209 return MergeTo; 210} 211 212LiveInterval::iterator 213LiveInterval::addRangeFrom(LiveRange LR, iterator From) { 214 unsigned Start = LR.start, End = LR.end; 215 iterator it = std::upper_bound(From, ranges.end(), Start); 216 217 // If the inserted interval starts in the middle or right at the end of 218 // another interval, just extend that interval to contain the range of LR. 219 if (it != ranges.begin()) { 220 iterator B = prior(it); 221 if (LR.valno == B->valno) { 222 if (B->start <= Start && B->end >= Start) { 223 extendIntervalEndTo(B, End); 224 return B; 225 } 226 } else { 227 // Check to make sure that we are not overlapping two live ranges with 228 // different valno's. 229 assert(B->end <= Start && 230 "Cannot overlap two LiveRanges with differing ValID's" 231 " (did you def the same reg twice in a MachineInstr?)"); 232 } 233 } 234 235 // Otherwise, if this range ends in the middle of, or right next to, another 236 // interval, merge it into that interval. 237 if (it != ranges.end()) { 238 if (LR.valno == it->valno) { 239 if (it->start <= End) { 240 it = extendIntervalStartTo(it, Start); 241 242 // If LR is a complete superset of an interval, we may need to grow its 243 // endpoint as well. 244 if (End > it->end) 245 extendIntervalEndTo(it, End); 246 else if (End < it->end) 247 // Overlapping intervals, there might have been a kill here. 248 removeKill(it->valno, End); 249 return it; 250 } 251 } else { 252 // Check to make sure that we are not overlapping two live ranges with 253 // different valno's. 254 assert(it->start >= End && 255 "Cannot overlap two LiveRanges with differing ValID's"); 256 } 257 } 258 259 // Otherwise, this is just a new range that doesn't interact with anything. 260 // Insert it. 261 return ranges.insert(it, LR); 262} 263 264/// isInOneLiveRange - Return true if the range specified is entirely in the 265/// a single LiveRange of the live interval. 266bool LiveInterval::isInOneLiveRange(unsigned Start, unsigned End) { 267 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 268 if (I == ranges.begin()) 269 return false; 270 --I; 271 return I->contains(Start) && I->contains(End-1); 272} 273 274 275/// removeRange - Remove the specified range from this interval. Note that 276/// the range must be in a single LiveRange in its entirety. 277void LiveInterval::removeRange(unsigned Start, unsigned End, 278 bool RemoveDeadValNo) { 279 // Find the LiveRange containing this span. 280 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 281 assert(I != ranges.begin() && "Range is not in interval!"); 282 --I; 283 assert(I->contains(Start) && I->contains(End-1) && 284 "Range is not entirely in interval!"); 285 286 // If the span we are removing is at the start of the LiveRange, adjust it. 287 VNInfo *ValNo = I->valno; 288 if (I->start == Start) { 289 if (I->end == End) { 290 removeKills(I->valno, Start, End); 291 if (RemoveDeadValNo) { 292 // Check if val# is dead. 293 bool isDead = true; 294 for (const_iterator II = begin(), EE = end(); II != EE; ++II) 295 if (II != I && II->valno == ValNo) { 296 isDead = false; 297 break; 298 } 299 if (isDead) { 300 // Now that ValNo is dead, remove it. If it is the largest value 301 // number, just nuke it (and any other deleted values neighboring it), 302 // otherwise mark it as ~1U so it can be nuked later. 303 if (ValNo->id == getNumValNums()-1) { 304 do { 305 VNInfo *VNI = valnos.back(); 306 valnos.pop_back(); 307 VNI->~VNInfo(); 308 } while (!valnos.empty() && valnos.back()->isUnused()); 309 } else { 310 ValNo->setIsUnused(true); 311 } 312 } 313 } 314 315 ranges.erase(I); // Removed the whole LiveRange. 316 } else 317 I->start = End; 318 return; 319 } 320 321 // Otherwise if the span we are removing is at the end of the LiveRange, 322 // adjust the other way. 323 if (I->end == End) { 324 removeKills(ValNo, Start, End); 325 I->end = Start; 326 return; 327 } 328 329 // Otherwise, we are splitting the LiveRange into two pieces. 330 unsigned OldEnd = I->end; 331 I->end = Start; // Trim the old interval. 332 333 // Insert the new one. 334 ranges.insert(next(I), LiveRange(End, OldEnd, ValNo)); 335} 336 337/// removeValNo - Remove all the ranges defined by the specified value#. 338/// Also remove the value# from value# list. 339void LiveInterval::removeValNo(VNInfo *ValNo) { 340 if (empty()) return; 341 Ranges::iterator I = ranges.end(); 342 Ranges::iterator E = ranges.begin(); 343 do { 344 --I; 345 if (I->valno == ValNo) 346 ranges.erase(I); 347 } while (I != E); 348 // Now that ValNo is dead, remove it. If it is the largest value 349 // number, just nuke it (and any other deleted values neighboring it), 350 // otherwise mark it as ~1U so it can be nuked later. 351 if (ValNo->id == getNumValNums()-1) { 352 do { 353 VNInfo *VNI = valnos.back(); 354 valnos.pop_back(); 355 VNI->~VNInfo(); 356 } while (!valnos.empty() && valnos.back()->isUnused()); 357 } else { 358 ValNo->setIsUnused(true); 359 } 360} 361 362/// scaleNumbering - Renumber VNI and ranges to provide gaps for new 363/// instructions. 364void LiveInterval::scaleNumbering(unsigned factor) { 365 // Scale ranges. 366 for (iterator RI = begin(), RE = end(); RI != RE; ++RI) { 367 RI->start = InstrSlots::scale(RI->start, factor); 368 RI->end = InstrSlots::scale(RI->end, factor); 369 } 370 371 // Scale VNI info. 372 for (vni_iterator VNI = vni_begin(), VNIE = vni_end(); VNI != VNIE; ++VNI) { 373 VNInfo *vni = *VNI; 374 375 if (vni->isDefAccurate()) 376 vni->def = InstrSlots::scale(vni->def, factor); 377 378 for (unsigned i = 0; i < vni->kills.size(); ++i) { 379 if (!vni->kills[i].isPHIKill) 380 vni->kills[i].killIdx = 381 InstrSlots::scale(vni->kills[i].killIdx, 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 ComputeJoinedWeight(Other); 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()->isUnused()); 597 } else { 598 V1->setIsUnused(true); 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(0, 0, false, 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(0, 0, false, 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 V1->copyFrom(*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()->isUnused()); 762 } else { 763 V1->setIsUnused(true); 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 createValueCopy(VNI, VNInfoAllocator); 781 } 782 for (unsigned i = 0, e = RHS.ranges.size(); i != e; ++i) { 783 const LiveRange &LR = RHS.ranges[i]; 784 addRange(LiveRange(LR.start, LR.end, getValNumInfo(LR.valno->id))); 785 } 786} 787 788unsigned LiveInterval::getSize() const { 789 unsigned Sum = 0; 790 for (const_iterator I = begin(), E = end(); I != E; ++I) 791 Sum += I->end - I->start; 792 return Sum; 793} 794 795/// ComputeJoinedWeight - Set the weight of a live interval Joined 796/// after Other has been merged into it. 797void LiveInterval::ComputeJoinedWeight(const LiveInterval &Other) { 798 // If either of these intervals was spilled, the weight is the 799 // weight of the non-spilled interval. This can only happen with 800 // iterative coalescers. 801 802 if (Other.weight != HUGE_VALF) { 803 weight += Other.weight; 804 } 805 else if (weight == HUGE_VALF && 806 !TargetRegisterInfo::isPhysicalRegister(reg)) { 807 // Remove this assert if you have an iterative coalescer 808 assert(0 && "Joining to spilled interval"); 809 weight = Other.weight; 810 } 811 else { 812 // Otherwise the weight stays the same 813 // Remove this assert if you have an iterative coalescer 814 assert(0 && "Joining from spilled interval"); 815 } 816} 817 818raw_ostream& llvm::operator<<(raw_ostream& os, const LiveRange &LR) { 819 return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")"; 820} 821 822void LiveRange::dump() const { 823 errs() << *this << "\n"; 824} 825 826void LiveInterval::print(raw_ostream &OS, const TargetRegisterInfo *TRI) const { 827 if (isStackSlot()) 828 OS << "SS#" << getStackSlotIndex(); 829 else if (TRI && TargetRegisterInfo::isPhysicalRegister(reg)) 830 OS << TRI->getName(reg); 831 else 832 OS << "%reg" << reg; 833 834 OS << ',' << weight; 835 836 if (empty()) 837 OS << " EMPTY"; 838 else { 839 OS << " = "; 840 for (LiveInterval::Ranges::const_iterator I = ranges.begin(), 841 E = ranges.end(); I != E; ++I) 842 OS << *I; 843 } 844 845 // Print value number info. 846 if (getNumValNums()) { 847 OS << " "; 848 unsigned vnum = 0; 849 for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e; 850 ++i, ++vnum) { 851 const VNInfo *vni = *i; 852 if (vnum) OS << " "; 853 OS << vnum << "@"; 854 if (vni->isUnused()) { 855 OS << "x"; 856 } else { 857 if (!vni->isDefAccurate()) 858 OS << "?"; 859 else 860 OS << vni->def; 861 unsigned ee = vni->kills.size(); 862 if (ee || vni->hasPHIKill()) { 863 OS << "-("; 864 for (unsigned j = 0; j != ee; ++j) { 865 OS << vni->kills[j].killIdx; 866 if (vni->kills[j].isPHIKill) 867 OS << "*"; 868 if (j != ee-1) 869 OS << " "; 870 } 871 if (vni->hasPHIKill()) { 872 if (ee) 873 OS << " "; 874 OS << "phi"; 875 } 876 OS << ")"; 877 } 878 } 879 } 880 } 881} 882 883void LiveInterval::dump() const { 884 errs() << *this << "\n"; 885} 886 887 888void LiveRange::print(raw_ostream &os) const { 889 os << *this; 890} 891