LiveInterval.cpp revision 23c2392eed45ae0e90168d24abf2fd109ad94b34
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/LiveIntervalAnalysis.h" 23#include "llvm/CodeGen/MachineRegisterInfo.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallSet.h" 26#include "llvm/ADT/STLExtras.h" 27#include "llvm/Support/Debug.h" 28#include "llvm/Support/raw_ostream.h" 29#include "llvm/Target/TargetRegisterInfo.h" 30#include <algorithm> 31using namespace llvm; 32 33// An example for liveAt(): 34// 35// this = [1,4), liveAt(0) will return false. The instruction defining this 36// spans slots [0,3]. The interval belongs to an spilled definition of the 37// variable it represents. This is because slot 1 is used (def slot) and spans 38// up to slot 3 (store slot). 39// 40bool LiveInterval::liveAt(SlotIndex I) const { 41 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 42 43 if (r == ranges.begin()) 44 return false; 45 46 --r; 47 return r->contains(I); 48} 49 50// liveBeforeAndAt - Check if the interval is live at the index and the index 51// just before it. If index is liveAt, check if it starts a new live range. 52// If it does, then check if the previous live range ends at index-1. 53bool LiveInterval::liveBeforeAndAt(SlotIndex I) const { 54 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 55 56 if (r == ranges.begin()) 57 return false; 58 59 --r; 60 if (!r->contains(I)) 61 return false; 62 if (I != r->start) 63 return true; 64 // I is the start of a live range. Check if the previous live range ends 65 // at I-1. 66 if (r == ranges.begin()) 67 return false; 68 return r->end == I; 69} 70 71// overlaps - Return true if the intersection of the two live intervals is 72// not empty. 73// 74// An example for overlaps(): 75// 76// 0: A = ... 77// 4: B = ... 78// 8: C = A + B ;; last use of A 79// 80// The live intervals should look like: 81// 82// A = [3, 11) 83// B = [7, x) 84// C = [11, y) 85// 86// A->overlaps(C) should return false since we want to be able to join 87// A and C. 88// 89bool LiveInterval::overlapsFrom(const LiveInterval& other, 90 const_iterator StartPos) const { 91 const_iterator i = begin(); 92 const_iterator ie = end(); 93 const_iterator j = StartPos; 94 const_iterator je = other.end(); 95 96 assert((StartPos->start <= i->start || StartPos == other.begin()) && 97 StartPos != other.end() && "Bogus start position hint!"); 98 99 if (i->start < j->start) { 100 i = std::upper_bound(i, ie, j->start); 101 if (i != ranges.begin()) --i; 102 } else if (j->start < i->start) { 103 ++StartPos; 104 if (StartPos != other.end() && StartPos->start <= i->start) { 105 assert(StartPos < other.end() && i < end()); 106 j = std::upper_bound(j, je, i->start); 107 if (j != other.ranges.begin()) --j; 108 } 109 } else { 110 return true; 111 } 112 113 if (j == je) return false; 114 115 while (i != ie) { 116 if (i->start > j->start) { 117 std::swap(i, j); 118 std::swap(ie, je); 119 } 120 121 if (i->end > j->start) 122 return true; 123 ++i; 124 } 125 126 return false; 127} 128 129/// overlaps - Return true if the live interval overlaps a range specified 130/// by [Start, End). 131bool LiveInterval::overlaps(SlotIndex Start, SlotIndex End) const { 132 assert(Start < End && "Invalid range"); 133 const_iterator I = begin(); 134 const_iterator E = end(); 135 const_iterator si = std::upper_bound(I, E, Start); 136 const_iterator ei = std::upper_bound(I, E, End); 137 if (si != ei) 138 return true; 139 if (si == I) 140 return false; 141 --si; 142 return si->contains(Start); 143} 144 145/// extendIntervalEndTo - This method is used when we want to extend the range 146/// specified by I to end at the specified endpoint. To do this, we should 147/// merge and eliminate all ranges that this will overlap with. The iterator is 148/// not invalidated. 149void LiveInterval::extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd) { 150 assert(I != ranges.end() && "Not a valid interval!"); 151 VNInfo *ValNo = I->valno; 152 SlotIndex OldEnd = I->end; 153 154 // Search for the first interval that we can't merge with. 155 Ranges::iterator MergeTo = next(I); 156 for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) { 157 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 158 } 159 160 // If NewEnd was in the middle of an interval, make sure to get its endpoint. 161 I->end = std::max(NewEnd, prior(MergeTo)->end); 162 163 // Erase any dead ranges. 164 ranges.erase(next(I), MergeTo); 165 166 // Update kill info. 167 ValNo->removeKills(OldEnd, I->end.getPrevSlot()); 168 169 // If the newly formed range now touches the range after it and if they have 170 // the same value number, merge the two ranges into one range. 171 Ranges::iterator Next = next(I); 172 if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) { 173 I->end = Next->end; 174 ranges.erase(Next); 175 } 176} 177 178 179/// extendIntervalStartTo - This method is used when we want to extend the range 180/// specified by I to start at the specified endpoint. To do this, we should 181/// merge and eliminate all ranges that this will overlap with. 182LiveInterval::Ranges::iterator 183LiveInterval::extendIntervalStartTo(Ranges::iterator I, SlotIndex NewStart) { 184 assert(I != ranges.end() && "Not a valid interval!"); 185 VNInfo *ValNo = I->valno; 186 187 // Search for the first interval that we can't merge with. 188 Ranges::iterator MergeTo = I; 189 do { 190 if (MergeTo == ranges.begin()) { 191 I->start = NewStart; 192 ranges.erase(MergeTo, I); 193 return I; 194 } 195 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 196 --MergeTo; 197 } while (NewStart <= MergeTo->start); 198 199 // If we start in the middle of another interval, just delete a range and 200 // extend that interval. 201 if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) { 202 MergeTo->end = I->end; 203 } else { 204 // Otherwise, extend the interval right after. 205 ++MergeTo; 206 MergeTo->start = NewStart; 207 MergeTo->end = I->end; 208 } 209 210 ranges.erase(next(MergeTo), next(I)); 211 return MergeTo; 212} 213 214LiveInterval::iterator 215LiveInterval::addRangeFrom(LiveRange LR, iterator From) { 216 SlotIndex Start = LR.start, End = LR.end; 217 iterator it = std::upper_bound(From, ranges.end(), Start); 218 219 // If the inserted interval starts in the middle or right at the end of 220 // another interval, just extend that interval to contain the range of LR. 221 if (it != ranges.begin()) { 222 iterator B = prior(it); 223 if (LR.valno == B->valno) { 224 if (B->start <= Start && B->end >= Start) { 225 extendIntervalEndTo(B, End); 226 return B; 227 } 228 } else { 229 // Check to make sure that we are not overlapping two live ranges with 230 // different valno's. 231 assert(B->end <= Start && 232 "Cannot overlap two LiveRanges with differing ValID's" 233 " (did you def the same reg twice in a MachineInstr?)"); 234 } 235 } 236 237 // Otherwise, if this range ends in the middle of, or right next to, another 238 // interval, merge it into that interval. 239 if (it != ranges.end()) { 240 if (LR.valno == it->valno) { 241 if (it->start <= End) { 242 it = extendIntervalStartTo(it, Start); 243 244 // If LR is a complete superset of an interval, we may need to grow its 245 // endpoint as well. 246 if (End > it->end) 247 extendIntervalEndTo(it, End); 248 else if (End < it->end) 249 // Overlapping intervals, there might have been a kill here. 250 it->valno->removeKill(End); 251 return it; 252 } 253 } else { 254 // Check to make sure that we are not overlapping two live ranges with 255 // different valno's. 256 assert(it->start >= End && 257 "Cannot overlap two LiveRanges with differing ValID's"); 258 } 259 } 260 261 // Otherwise, this is just a new range that doesn't interact with anything. 262 // Insert it. 263 return ranges.insert(it, LR); 264} 265 266/// isInOneLiveRange - Return true if the range specified is entirely in 267/// a single LiveRange of the live interval. 268bool LiveInterval::isInOneLiveRange(SlotIndex Start, SlotIndex End) { 269 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 270 if (I == ranges.begin()) 271 return false; 272 --I; 273 return I->containsRange(Start, End); 274} 275 276 277/// removeRange - Remove the specified range from this interval. Note that 278/// the range must be in a single LiveRange in its entirety. 279void LiveInterval::removeRange(SlotIndex Start, SlotIndex End, 280 bool RemoveDeadValNo) { 281 // Find the LiveRange containing this span. 282 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 283 assert(I != ranges.begin() && "Range is not in interval!"); 284 --I; 285 assert(I->containsRange(Start, End) && "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 ValNo->removeKills(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()->isUnused()); 310 } else { 311 ValNo->setIsUnused(true); 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 ValNo->removeKills(Start, End); 326 I->end = Start; 327 return; 328 } 329 330 // Otherwise, we are splitting the LiveRange into two pieces. 331 SlotIndex 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()->isUnused()); 358 } else { 359 ValNo->setIsUnused(true); 360 } 361} 362 363/// getLiveRangeContaining - Return the live range that contains the 364/// specified index, or null if there is none. 365LiveInterval::const_iterator 366LiveInterval::FindLiveRangeContaining(SlotIndex Idx) const { 367 const_iterator It = std::upper_bound(begin(), end(), Idx); 368 if (It != ranges.begin()) { 369 --It; 370 if (It->contains(Idx)) 371 return It; 372 } 373 374 return end(); 375} 376 377LiveInterval::iterator 378LiveInterval::FindLiveRangeContaining(SlotIndex Idx) { 379 iterator It = std::upper_bound(begin(), end(), Idx); 380 if (It != begin()) { 381 --It; 382 if (It->contains(Idx)) 383 return It; 384 } 385 386 return end(); 387} 388 389/// findDefinedVNInfo - Find the VNInfo defined by the specified 390/// index (register interval). 391VNInfo *LiveInterval::findDefinedVNInfoForRegInt(SlotIndex Idx) const { 392 for (LiveInterval::const_vni_iterator i = vni_begin(), e = vni_end(); 393 i != e; ++i) { 394 if ((*i)->def == Idx) 395 return *i; 396 } 397 398 return 0; 399} 400 401/// findDefinedVNInfo - Find the VNInfo defined by the specified 402/// register (stack inteval). 403VNInfo *LiveInterval::findDefinedVNInfoForStackInt(unsigned reg) const { 404 for (LiveInterval::const_vni_iterator i = vni_begin(), e = vni_end(); 405 i != e; ++i) { 406 if ((*i)->getReg() == reg) 407 return *i; 408 } 409 return 0; 410} 411 412/// join - Join two live intervals (this, and other) together. This applies 413/// mappings to the value numbers in the LHS/RHS intervals as specified. If 414/// the intervals are not joinable, this aborts. 415void LiveInterval::join(LiveInterval &Other, 416 const int *LHSValNoAssignments, 417 const int *RHSValNoAssignments, 418 SmallVector<VNInfo*, 16> &NewVNInfo, 419 MachineRegisterInfo *MRI) { 420 // Determine if any of our live range values are mapped. This is uncommon, so 421 // we want to avoid the interval scan if not. 422 bool MustMapCurValNos = false; 423 unsigned NumVals = getNumValNums(); 424 unsigned NumNewVals = NewVNInfo.size(); 425 for (unsigned i = 0; i != NumVals; ++i) { 426 unsigned LHSValID = LHSValNoAssignments[i]; 427 if (i != LHSValID || 428 (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) 429 MustMapCurValNos = true; 430 } 431 432 // If we have to apply a mapping to our base interval assignment, rewrite it 433 // now. 434 if (MustMapCurValNos) { 435 // Map the first live range. 436 iterator OutIt = begin(); 437 OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]]; 438 ++OutIt; 439 for (iterator I = OutIt, E = end(); I != E; ++I) { 440 OutIt->valno = NewVNInfo[LHSValNoAssignments[I->valno->id]]; 441 442 // If this live range has the same value # as its immediate predecessor, 443 // and if they are neighbors, remove one LiveRange. This happens when we 444 // have [0,3:0)[4,7:1) and map 0/1 onto the same value #. 445 if (OutIt->valno == (OutIt-1)->valno && (OutIt-1)->end == OutIt->start) { 446 (OutIt-1)->end = OutIt->end; 447 } else { 448 if (I != OutIt) { 449 OutIt->start = I->start; 450 OutIt->end = I->end; 451 } 452 453 // Didn't merge, on to the next one. 454 ++OutIt; 455 } 456 } 457 458 // If we merge some live ranges, chop off the end. 459 ranges.erase(OutIt, end()); 460 } 461 462 // Remember assignements because val# ids are changing. 463 SmallVector<unsigned, 16> OtherAssignments; 464 for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) 465 OtherAssignments.push_back(RHSValNoAssignments[I->valno->id]); 466 467 // Update val# info. Renumber them and make sure they all belong to this 468 // LiveInterval now. Also remove dead val#'s. 469 unsigned NumValNos = 0; 470 for (unsigned i = 0; i < NumNewVals; ++i) { 471 VNInfo *VNI = NewVNInfo[i]; 472 if (VNI) { 473 if (NumValNos >= NumVals) 474 valnos.push_back(VNI); 475 else 476 valnos[NumValNos] = VNI; 477 VNI->id = NumValNos++; // Renumber val#. 478 } 479 } 480 if (NumNewVals < NumVals) 481 valnos.resize(NumNewVals); // shrinkify 482 483 // Okay, now insert the RHS live ranges into the LHS. 484 iterator InsertPos = begin(); 485 unsigned RangeNo = 0; 486 for (iterator I = Other.begin(), E = Other.end(); I != E; ++I, ++RangeNo) { 487 // Map the valno in the other live range to the current live range. 488 I->valno = NewVNInfo[OtherAssignments[RangeNo]]; 489 assert(I->valno && "Adding a dead range?"); 490 InsertPos = addRangeFrom(*I, InsertPos); 491 } 492 493 ComputeJoinedWeight(Other); 494 495 // Update regalloc hint if currently there isn't one. 496 if (TargetRegisterInfo::isVirtualRegister(reg) && 497 TargetRegisterInfo::isVirtualRegister(Other.reg)) { 498 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(reg); 499 if (Hint.first == 0 && Hint.second == 0) { 500 std::pair<unsigned, unsigned> OtherHint = 501 MRI->getRegAllocationHint(Other.reg); 502 if (OtherHint.first || OtherHint.second) 503 MRI->setRegAllocationHint(reg, OtherHint.first, OtherHint.second); 504 } 505 } 506} 507 508/// MergeRangesInAsValue - Merge all of the intervals in RHS into this live 509/// interval as the specified value number. The LiveRanges in RHS are 510/// allowed to overlap with LiveRanges in the current interval, but only if 511/// the overlapping LiveRanges have the specified value number. 512void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS, 513 VNInfo *LHSValNo) { 514 // TODO: Make this more efficient. 515 iterator InsertPos = begin(); 516 for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { 517 // Map the valno in the other live range to the current live range. 518 LiveRange Tmp = *I; 519 Tmp.valno = LHSValNo; 520 InsertPos = addRangeFrom(Tmp, InsertPos); 521 } 522} 523 524 525/// MergeValueInAsValue - Merge all of the live ranges of a specific val# 526/// in RHS into this live interval as the specified value number. 527/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the 528/// current interval, it will replace the value numbers of the overlaped 529/// live ranges with the specified value number. 530void LiveInterval::MergeValueInAsValue( 531 const LiveInterval &RHS, 532 const VNInfo *RHSValNo, VNInfo *LHSValNo) { 533 SmallVector<VNInfo*, 4> ReplacedValNos; 534 iterator IP = begin(); 535 for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { 536 if (I->valno != RHSValNo) 537 continue; 538 SlotIndex Start = I->start, End = I->end; 539 IP = std::upper_bound(IP, end(), Start); 540 // If the start of this range overlaps with an existing liverange, trim it. 541 if (IP != begin() && IP[-1].end > Start) { 542 if (IP[-1].valno != LHSValNo) { 543 ReplacedValNos.push_back(IP[-1].valno); 544 IP[-1].valno = LHSValNo; // Update val#. 545 } 546 Start = IP[-1].end; 547 // Trimmed away the whole range? 548 if (Start >= End) continue; 549 } 550 // If the end of this range overlaps with an existing liverange, trim it. 551 if (IP != end() && End > IP->start) { 552 if (IP->valno != LHSValNo) { 553 ReplacedValNos.push_back(IP->valno); 554 IP->valno = LHSValNo; // Update val#. 555 } 556 End = IP->start; 557 // If this trimmed away the whole range, ignore it. 558 if (Start == End) continue; 559 } 560 561 // Map the valno in the other live range to the current live range. 562 IP = addRangeFrom(LiveRange(Start, End, LHSValNo), IP); 563 } 564 565 566 SmallSet<VNInfo*, 4> Seen; 567 for (unsigned i = 0, e = ReplacedValNos.size(); i != e; ++i) { 568 VNInfo *V1 = ReplacedValNos[i]; 569 if (Seen.insert(V1)) { 570 bool isDead = true; 571 for (const_iterator I = begin(), E = end(); I != E; ++I) 572 if (I->valno == V1) { 573 isDead = false; 574 break; 575 } 576 if (isDead) { 577 // Now that V1 is dead, remove it. If it is the largest value number, 578 // just nuke it (and any other deleted values neighboring it), otherwise 579 // mark it as ~1U so it can be nuked later. 580 if (V1->id == getNumValNums()-1) { 581 do { 582 VNInfo *VNI = valnos.back(); 583 valnos.pop_back(); 584 VNI->~VNInfo(); 585 } while (!valnos.empty() && valnos.back()->isUnused()); 586 } else { 587 V1->setIsUnused(true); 588 } 589 } 590 } 591 } 592} 593 594 595/// MergeInClobberRanges - For any live ranges that are not defined in the 596/// current interval, but are defined in the Clobbers interval, mark them 597/// used with an unknown definition value. 598void LiveInterval::MergeInClobberRanges(LiveIntervals &li_, 599 const LiveInterval &Clobbers, 600 BumpPtrAllocator &VNInfoAllocator) { 601 if (Clobbers.empty()) return; 602 603 DenseMap<VNInfo*, VNInfo*> ValNoMaps; 604 VNInfo *UnusedValNo = 0; 605 iterator IP = begin(); 606 for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) { 607 // For every val# in the Clobbers interval, create a new "unknown" val#. 608 VNInfo *ClobberValNo = 0; 609 DenseMap<VNInfo*, VNInfo*>::iterator VI = ValNoMaps.find(I->valno); 610 if (VI != ValNoMaps.end()) 611 ClobberValNo = VI->second; 612 else if (UnusedValNo) 613 ClobberValNo = UnusedValNo; 614 else { 615 UnusedValNo = ClobberValNo = 616 getNextValue(li_.getInvalidIndex(), 0, false, VNInfoAllocator); 617 ValNoMaps.insert(std::make_pair(I->valno, ClobberValNo)); 618 } 619 620 bool Done = false; 621 SlotIndex Start = I->start, End = I->end; 622 // If a clobber range starts before an existing range and ends after 623 // it, the clobber range will need to be split into multiple ranges. 624 // Loop until the entire clobber range is handled. 625 while (!Done) { 626 Done = true; 627 IP = std::upper_bound(IP, end(), Start); 628 SlotIndex SubRangeStart = Start; 629 SlotIndex SubRangeEnd = End; 630 631 // If the start of this range overlaps with an existing liverange, trim it. 632 if (IP != begin() && IP[-1].end > SubRangeStart) { 633 SubRangeStart = IP[-1].end; 634 // Trimmed away the whole range? 635 if (SubRangeStart >= SubRangeEnd) continue; 636 } 637 // If the end of this range overlaps with an existing liverange, trim it. 638 if (IP != end() && SubRangeEnd > IP->start) { 639 // If the clobber live range extends beyond the existing live range, 640 // it'll need at least another live range, so set the flag to keep 641 // iterating. 642 if (SubRangeEnd > IP->end) { 643 Start = IP->end; 644 Done = false; 645 } 646 SubRangeEnd = IP->start; 647 // If this trimmed away the whole range, ignore it. 648 if (SubRangeStart == SubRangeEnd) continue; 649 } 650 651 // Insert the clobber interval. 652 IP = addRangeFrom(LiveRange(SubRangeStart, SubRangeEnd, ClobberValNo), 653 IP); 654 UnusedValNo = 0; 655 } 656 } 657 658 if (UnusedValNo) { 659 // Delete the last unused val#. 660 valnos.pop_back(); 661 UnusedValNo->~VNInfo(); 662 } 663} 664 665void LiveInterval::MergeInClobberRange(LiveIntervals &li_, 666 SlotIndex Start, 667 SlotIndex End, 668 BumpPtrAllocator &VNInfoAllocator) { 669 // Find a value # to use for the clobber ranges. If there is already a value# 670 // for unknown values, use it. 671 VNInfo *ClobberValNo = 672 getNextValue(li_.getInvalidIndex(), 0, false, VNInfoAllocator); 673 674 iterator IP = begin(); 675 IP = std::upper_bound(IP, end(), Start); 676 677 // If the start of this range overlaps with an existing liverange, trim it. 678 if (IP != begin() && IP[-1].end > Start) { 679 Start = IP[-1].end; 680 // Trimmed away the whole range? 681 if (Start >= End) return; 682 } 683 // If the end of this range overlaps with an existing liverange, trim it. 684 if (IP != end() && End > IP->start) { 685 End = IP->start; 686 // If this trimmed away the whole range, ignore it. 687 if (Start == End) return; 688 } 689 690 // Insert the clobber interval. 691 addRangeFrom(LiveRange(Start, End, ClobberValNo), IP); 692} 693 694/// MergeValueNumberInto - This method is called when two value nubmers 695/// are found to be equivalent. This eliminates V1, replacing all 696/// LiveRanges with the V1 value number with the V2 value number. This can 697/// cause merging of V1/V2 values numbers and compaction of the value space. 698VNInfo* LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) { 699 assert(V1 != V2 && "Identical value#'s are always equivalent!"); 700 701 // This code actually merges the (numerically) larger value number into the 702 // smaller value number, which is likely to allow us to compactify the value 703 // space. The only thing we have to be careful of is to preserve the 704 // instruction that defines the result value. 705 706 // Make sure V2 is smaller than V1. 707 if (V1->id < V2->id) { 708 V1->copyFrom(*V2); 709 std::swap(V1, V2); 710 } 711 712 // Merge V1 live ranges into V2. 713 for (iterator I = begin(); I != end(); ) { 714 iterator LR = I++; 715 if (LR->valno != V1) continue; // Not a V1 LiveRange. 716 717 // Okay, we found a V1 live range. If it had a previous, touching, V2 live 718 // range, extend it. 719 if (LR != begin()) { 720 iterator Prev = LR-1; 721 if (Prev->valno == V2 && Prev->end == LR->start) { 722 Prev->end = LR->end; 723 724 // Erase this live-range. 725 ranges.erase(LR); 726 I = Prev+1; 727 LR = Prev; 728 } 729 } 730 731 // Okay, now we have a V1 or V2 live range that is maximally merged forward. 732 // Ensure that it is a V2 live-range. 733 LR->valno = V2; 734 735 // If we can merge it into later V2 live ranges, do so now. We ignore any 736 // following V1 live ranges, as they will be merged in subsequent iterations 737 // of the loop. 738 if (I != end()) { 739 if (I->start == LR->end && I->valno == V2) { 740 LR->end = I->end; 741 ranges.erase(I); 742 I = LR+1; 743 } 744 } 745 } 746 747 // Now that V1 is dead, remove it. If it is the largest value number, just 748 // nuke it (and any other deleted values neighboring it), otherwise mark it as 749 // ~1U so it can be nuked later. 750 if (V1->id == getNumValNums()-1) { 751 do { 752 VNInfo *VNI = valnos.back(); 753 valnos.pop_back(); 754 VNI->~VNInfo(); 755 } while (valnos.back()->isUnused()); 756 } else { 757 V1->setIsUnused(true); 758 } 759 760 return V2; 761} 762 763void LiveInterval::Copy(const LiveInterval &RHS, 764 MachineRegisterInfo *MRI, 765 BumpPtrAllocator &VNInfoAllocator) { 766 ranges.clear(); 767 valnos.clear(); 768 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(RHS.reg); 769 MRI->setRegAllocationHint(reg, Hint.first, Hint.second); 770 771 weight = RHS.weight; 772 for (unsigned i = 0, e = RHS.getNumValNums(); i != e; ++i) { 773 const VNInfo *VNI = RHS.getValNumInfo(i); 774 createValueCopy(VNI, VNInfoAllocator); 775 } 776 for (unsigned i = 0, e = RHS.ranges.size(); i != e; ++i) { 777 const LiveRange &LR = RHS.ranges[i]; 778 addRange(LiveRange(LR.start, LR.end, getValNumInfo(LR.valno->id))); 779 } 780} 781 782unsigned LiveInterval::getSize() const { 783 unsigned Sum = 0; 784 for (const_iterator I = begin(), E = end(); I != E; ++I) 785 Sum += I->start.distance(I->end); 786 return Sum; 787} 788 789/// ComputeJoinedWeight - Set the weight of a live interval Joined 790/// after Other has been merged into it. 791void LiveInterval::ComputeJoinedWeight(const LiveInterval &Other) { 792 // If either of these intervals was spilled, the weight is the 793 // weight of the non-spilled interval. This can only happen with 794 // iterative coalescers. 795 796 if (Other.weight != HUGE_VALF) { 797 weight += Other.weight; 798 } 799 else if (weight == HUGE_VALF && 800 !TargetRegisterInfo::isPhysicalRegister(reg)) { 801 // Remove this assert if you have an iterative coalescer 802 assert(0 && "Joining to spilled interval"); 803 weight = Other.weight; 804 } 805 else { 806 // Otherwise the weight stays the same 807 // Remove this assert if you have an iterative coalescer 808 assert(0 && "Joining from spilled interval"); 809 } 810} 811 812raw_ostream& llvm::operator<<(raw_ostream& os, const LiveRange &LR) { 813 return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")"; 814} 815 816void LiveRange::dump() const { 817 dbgs() << *this << "\n"; 818} 819 820void LiveInterval::print(raw_ostream &OS, const TargetRegisterInfo *TRI) const { 821 if (isStackSlot()) 822 OS << "SS#" << getStackSlotIndex(); 823 else if (TRI && TargetRegisterInfo::isPhysicalRegister(reg)) 824 OS << TRI->getName(reg); 825 else 826 OS << "%reg" << reg; 827 828 OS << ',' << weight; 829 830 if (empty()) 831 OS << " EMPTY"; 832 else { 833 OS << " = "; 834 for (LiveInterval::Ranges::const_iterator I = ranges.begin(), 835 E = ranges.end(); I != E; ++I) 836 OS << *I; 837 } 838 839 // Print value number info. 840 if (getNumValNums()) { 841 OS << " "; 842 unsigned vnum = 0; 843 for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e; 844 ++i, ++vnum) { 845 const VNInfo *vni = *i; 846 if (vnum) OS << " "; 847 OS << vnum << "@"; 848 if (vni->isUnused()) { 849 OS << "x"; 850 } else { 851 if (!vni->isDefAccurate() && !vni->isPHIDef()) 852 OS << "?"; 853 else 854 OS << vni->def; 855 unsigned ee = vni->kills.size(); 856 if (ee || vni->hasPHIKill()) { 857 OS << "-("; 858 for (unsigned j = 0; j != ee; ++j) { 859 OS << vni->kills[j]; 860 if (j != ee-1) 861 OS << " "; 862 } 863 if (vni->hasPHIKill()) { 864 if (ee) 865 OS << " "; 866 OS << "phi"; 867 } 868 OS << ")"; 869 } 870 } 871 } 872 } 873} 874 875void LiveInterval::dump() const { 876 dbgs() << *this << "\n"; 877} 878 879 880void LiveRange::print(raw_ostream &os) const { 881 os << *this; 882} 883