LiveInterval.cpp revision 4cedb1c3efcf949dd5c719a282a2ffadda9af200
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/ADT/SmallSet.h" 23#include "llvm/ADT/STLExtras.h" 24#include "llvm/Support/Streams.h" 25#include "llvm/Target/TargetRegisterInfo.h" 26#include <algorithm> 27#include <ostream> 28using namespace llvm; 29 30// An example for liveAt(): 31// 32// this = [1,4), liveAt(0) will return false. The instruction defining this 33// spans slots [0,3]. The interval belongs to an spilled definition of the 34// variable it represents. This is because slot 1 is used (def slot) and spans 35// up to slot 3 (store slot). 36// 37bool LiveInterval::liveAt(unsigned I) const { 38 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 39 40 if (r == ranges.begin()) 41 return false; 42 43 --r; 44 return r->contains(I); 45} 46 47// liveBeforeAndAt - Check if the interval is live at the index and the index 48// just before it. If index is liveAt, check if it starts a new live range. 49// If it does, then check if the previous live range ends at index-1. 50bool LiveInterval::liveBeforeAndAt(unsigned I) const { 51 Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); 52 53 if (r == ranges.begin()) 54 return false; 55 56 --r; 57 if (!r->contains(I)) 58 return false; 59 if (I != r->start) 60 return true; 61 // I is the start of a live range. Check if the previous live range ends 62 // at I-1. 63 if (r == ranges.begin()) 64 return false; 65 return r->end == I; 66} 67 68// overlaps - Return true if the intersection of the two live intervals is 69// not empty. 70// 71// An example for overlaps(): 72// 73// 0: A = ... 74// 4: B = ... 75// 8: C = A + B ;; last use of A 76// 77// The live intervals should look like: 78// 79// A = [3, 11) 80// B = [7, x) 81// C = [11, y) 82// 83// A->overlaps(C) should return false since we want to be able to join 84// A and C. 85// 86bool LiveInterval::overlapsFrom(const LiveInterval& other, 87 const_iterator StartPos) const { 88 const_iterator i = begin(); 89 const_iterator ie = end(); 90 const_iterator j = StartPos; 91 const_iterator je = other.end(); 92 93 assert((StartPos->start <= i->start || StartPos == other.begin()) && 94 StartPos != other.end() && "Bogus start position hint!"); 95 96 if (i->start < j->start) { 97 i = std::upper_bound(i, ie, j->start); 98 if (i != ranges.begin()) --i; 99 } else if (j->start < i->start) { 100 ++StartPos; 101 if (StartPos != other.end() && StartPos->start <= i->start) { 102 assert(StartPos < other.end() && i < end()); 103 j = std::upper_bound(j, je, i->start); 104 if (j != other.ranges.begin()) --j; 105 } 106 } else { 107 return true; 108 } 109 110 if (j == je) return false; 111 112 while (i != ie) { 113 if (i->start > j->start) { 114 std::swap(i, j); 115 std::swap(ie, je); 116 } 117 118 if (i->end > j->start) 119 return true; 120 ++i; 121 } 122 123 return false; 124} 125 126/// extendIntervalEndTo - This method is used when we want to extend the range 127/// specified by I to end at the specified endpoint. To do this, we should 128/// merge and eliminate all ranges that this will overlap with. The iterator is 129/// not invalidated. 130void LiveInterval::extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd) { 131 assert(I != ranges.end() && "Not a valid interval!"); 132 VNInfo *ValNo = I->valno; 133 unsigned OldEnd = I->end; 134 135 // Search for the first interval that we can't merge with. 136 Ranges::iterator MergeTo = next(I); 137 for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) { 138 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 139 } 140 141 // If NewEnd was in the middle of an interval, make sure to get its endpoint. 142 I->end = std::max(NewEnd, prior(MergeTo)->end); 143 144 // Erase any dead ranges. 145 ranges.erase(next(I), MergeTo); 146 147 // Update kill info. 148 removeKills(ValNo, OldEnd, I->end-1); 149 150 // If the newly formed range now touches the range after it and if they have 151 // the same value number, merge the two ranges into one range. 152 Ranges::iterator Next = next(I); 153 if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) { 154 I->end = Next->end; 155 ranges.erase(Next); 156 } 157} 158 159 160/// extendIntervalStartTo - This method is used when we want to extend the range 161/// specified by I to start at the specified endpoint. To do this, we should 162/// merge and eliminate all ranges that this will overlap with. 163LiveInterval::Ranges::iterator 164LiveInterval::extendIntervalStartTo(Ranges::iterator I, unsigned NewStart) { 165 assert(I != ranges.end() && "Not a valid interval!"); 166 VNInfo *ValNo = I->valno; 167 168 // Search for the first interval that we can't merge with. 169 Ranges::iterator MergeTo = I; 170 do { 171 if (MergeTo == ranges.begin()) { 172 I->start = NewStart; 173 ranges.erase(MergeTo, I); 174 return I; 175 } 176 assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); 177 --MergeTo; 178 } while (NewStart <= MergeTo->start); 179 180 // If we start in the middle of another interval, just delete a range and 181 // extend that interval. 182 if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) { 183 MergeTo->end = I->end; 184 } else { 185 // Otherwise, extend the interval right after. 186 ++MergeTo; 187 MergeTo->start = NewStart; 188 MergeTo->end = I->end; 189 } 190 191 ranges.erase(next(MergeTo), next(I)); 192 return MergeTo; 193} 194 195LiveInterval::iterator 196LiveInterval::addRangeFrom(LiveRange LR, iterator From) { 197 unsigned Start = LR.start, End = LR.end; 198 iterator it = std::upper_bound(From, ranges.end(), Start); 199 200 // If the inserted interval starts in the middle or right at the end of 201 // another interval, just extend that interval to contain the range of LR. 202 if (it != ranges.begin()) { 203 iterator B = prior(it); 204 if (LR.valno == B->valno) { 205 if (B->start <= Start && B->end >= Start) { 206 extendIntervalEndTo(B, End); 207 return B; 208 } 209 } else { 210 // Check to make sure that we are not overlapping two live ranges with 211 // different valno's. 212 assert(B->end <= Start && 213 "Cannot overlap two LiveRanges with differing ValID's" 214 " (did you def the same reg twice in a MachineInstr?)"); 215 } 216 } 217 218 // Otherwise, if this range ends in the middle of, or right next to, another 219 // interval, merge it into that interval. 220 if (it != ranges.end()) { 221 if (LR.valno == it->valno) { 222 if (it->start <= End) { 223 it = extendIntervalStartTo(it, Start); 224 225 // If LR is a complete superset of an interval, we may need to grow its 226 // endpoint as well. 227 if (End > it->end) 228 extendIntervalEndTo(it, End); 229 else if (End < it->end) 230 // Overlapping intervals, there might have been a kill here. 231 removeKill(it->valno, End); 232 return it; 233 } 234 } else { 235 // Check to make sure that we are not overlapping two live ranges with 236 // different valno's. 237 assert(it->start >= End && 238 "Cannot overlap two LiveRanges with differing ValID's"); 239 } 240 } 241 242 // Otherwise, this is just a new range that doesn't interact with anything. 243 // Insert it. 244 return ranges.insert(it, LR); 245} 246 247/// isInOneLiveRange - Return true if the range specified is entirely in the 248/// a single LiveRange of the live interval. 249bool LiveInterval::isInOneLiveRange(unsigned Start, unsigned End) { 250 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 251 if (I == ranges.begin()) 252 return false; 253 --I; 254 return I->contains(Start) && I->contains(End-1); 255} 256 257 258/// removeRange - Remove the specified range from this interval. Note that 259/// the range must be in a single LiveRange in its entirety. 260void LiveInterval::removeRange(unsigned Start, unsigned End, 261 bool RemoveDeadValNo) { 262 // Find the LiveRange containing this span. 263 Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); 264 assert(I != ranges.begin() && "Range is not in interval!"); 265 --I; 266 assert(I->contains(Start) && I->contains(End-1) && 267 "Range is not entirely in interval!"); 268 269 // If the span we are removing is at the start of the LiveRange, adjust it. 270 VNInfo *ValNo = I->valno; 271 if (I->start == Start) { 272 if (I->end == End) { 273 removeKills(I->valno, Start, End); 274 if (RemoveDeadValNo) { 275 // Check if val# is dead. 276 bool isDead = true; 277 for (const_iterator II = begin(), EE = end(); II != EE; ++II) 278 if (II != I && II->valno == ValNo) { 279 isDead = false; 280 break; 281 } 282 if (isDead) { 283 // Now that ValNo is dead, remove it. If it is the largest value 284 // number, just nuke it (and any other deleted values neighboring it), 285 // otherwise mark it as ~1U so it can be nuked later. 286 if (ValNo->id == getNumValNums()-1) { 287 do { 288 VNInfo *VNI = valnos.back(); 289 valnos.pop_back(); 290 VNI->~VNInfo(); 291 } while (!valnos.empty() && valnos.back()->def == ~1U); 292 } else { 293 ValNo->def = ~1U; 294 } 295 } 296 } 297 298 ranges.erase(I); // Removed the whole LiveRange. 299 } else 300 I->start = End; 301 return; 302 } 303 304 // Otherwise if the span we are removing is at the end of the LiveRange, 305 // adjust the other way. 306 if (I->end == End) { 307 removeKills(ValNo, Start, End); 308 I->end = Start; 309 return; 310 } 311 312 // Otherwise, we are splitting the LiveRange into two pieces. 313 unsigned OldEnd = I->end; 314 I->end = Start; // Trim the old interval. 315 316 // Insert the new one. 317 ranges.insert(next(I), LiveRange(End, OldEnd, ValNo)); 318} 319 320/// removeValNo - Remove all the ranges defined by the specified value#. 321/// Also remove the value# from value# list. 322void LiveInterval::removeValNo(VNInfo *ValNo) { 323 if (empty()) return; 324 Ranges::iterator I = ranges.end(); 325 Ranges::iterator E = ranges.begin(); 326 do { 327 --I; 328 if (I->valno == ValNo) 329 ranges.erase(I); 330 } while (I != E); 331 // Now that ValNo is dead, remove it. If it is the largest value 332 // number, just nuke it (and any other deleted values neighboring it), 333 // otherwise mark it as ~1U so it can be nuked later. 334 if (ValNo->id == getNumValNums()-1) { 335 do { 336 VNInfo *VNI = valnos.back(); 337 valnos.pop_back(); 338 VNI->~VNInfo(); 339 } while (!valnos.empty() && valnos.back()->def == ~1U); 340 } else { 341 ValNo->def = ~1U; 342 } 343} 344 345/// getLiveRangeContaining - Return the live range that contains the 346/// specified index, or null if there is none. 347LiveInterval::const_iterator 348LiveInterval::FindLiveRangeContaining(unsigned Idx) const { 349 const_iterator It = std::upper_bound(begin(), end(), Idx); 350 if (It != ranges.begin()) { 351 --It; 352 if (It->contains(Idx)) 353 return It; 354 } 355 356 return end(); 357} 358 359LiveInterval::iterator 360LiveInterval::FindLiveRangeContaining(unsigned Idx) { 361 iterator It = std::upper_bound(begin(), end(), Idx); 362 if (It != begin()) { 363 --It; 364 if (It->contains(Idx)) 365 return It; 366 } 367 368 return end(); 369} 370 371/// findDefinedVNInfo - Find the VNInfo that's defined at the specified index 372/// (register interval) or defined by the specified register (stack inteval). 373VNInfo *LiveInterval::findDefinedVNInfo(unsigned DefIdxOrReg) const { 374 VNInfo *VNI = NULL; 375 for (LiveInterval::const_vni_iterator i = vni_begin(), e = vni_end(); 376 i != e; ++i) 377 if ((*i)->def == DefIdxOrReg) { 378 VNI = *i; 379 break; 380 } 381 return VNI; 382} 383 384 385/// join - Join two live intervals (this, and other) together. This applies 386/// mappings to the value numbers in the LHS/RHS intervals as specified. If 387/// the intervals are not joinable, this aborts. 388void LiveInterval::join(LiveInterval &Other, const int *LHSValNoAssignments, 389 const int *RHSValNoAssignments, 390 SmallVector<VNInfo*, 16> &NewVNInfo) { 391 // Determine if any of our live range values are mapped. This is uncommon, so 392 // we want to avoid the interval scan if not. 393 bool MustMapCurValNos = false; 394 unsigned NumVals = getNumValNums(); 395 unsigned NumNewVals = NewVNInfo.size(); 396 for (unsigned i = 0; i != NumVals; ++i) { 397 unsigned LHSValID = LHSValNoAssignments[i]; 398 if (i != LHSValID || 399 (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) 400 MustMapCurValNos = true; 401 } 402 403 // If we have to apply a mapping to our base interval assignment, rewrite it 404 // now. 405 if (MustMapCurValNos) { 406 // Map the first live range. 407 iterator OutIt = begin(); 408 OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]]; 409 ++OutIt; 410 for (iterator I = OutIt, E = end(); I != E; ++I) { 411 OutIt->valno = NewVNInfo[LHSValNoAssignments[I->valno->id]]; 412 413 // If this live range has the same value # as its immediate predecessor, 414 // and if they are neighbors, remove one LiveRange. This happens when we 415 // have [0,3:0)[4,7:1) and map 0/1 onto the same value #. 416 if (OutIt->valno == (OutIt-1)->valno && (OutIt-1)->end == OutIt->start) { 417 (OutIt-1)->end = OutIt->end; 418 } else { 419 if (I != OutIt) { 420 OutIt->start = I->start; 421 OutIt->end = I->end; 422 } 423 424 // Didn't merge, on to the next one. 425 ++OutIt; 426 } 427 } 428 429 // If we merge some live ranges, chop off the end. 430 ranges.erase(OutIt, end()); 431 } 432 433 // Remember assignements because val# ids are changing. 434 SmallVector<unsigned, 16> OtherAssignments; 435 for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) 436 OtherAssignments.push_back(RHSValNoAssignments[I->valno->id]); 437 438 // Update val# info. Renumber them and make sure they all belong to this 439 // LiveInterval now. Also remove dead val#'s. 440 unsigned NumValNos = 0; 441 for (unsigned i = 0; i < NumNewVals; ++i) { 442 VNInfo *VNI = NewVNInfo[i]; 443 if (VNI) { 444 if (i >= NumVals) 445 valnos.push_back(VNI); 446 else 447 valnos[NumValNos] = VNI; 448 VNI->id = NumValNos++; // Renumber val#. 449 } 450 } 451 if (NumNewVals < NumVals) 452 valnos.resize(NumNewVals); // shrinkify 453 454 // Okay, now insert the RHS live ranges into the LHS. 455 iterator InsertPos = begin(); 456 unsigned RangeNo = 0; 457 for (iterator I = Other.begin(), E = Other.end(); I != E; ++I, ++RangeNo) { 458 // Map the valno in the other live range to the current live range. 459 I->valno = NewVNInfo[OtherAssignments[RangeNo]]; 460 assert(I->valno && "Adding a dead range?"); 461 InsertPos = addRangeFrom(*I, InsertPos); 462 } 463 464 weight += Other.weight; 465 if (Other.preference && !preference) 466 preference = Other.preference; 467} 468 469/// MergeRangesInAsValue - Merge all of the intervals in RHS into this live 470/// interval as the specified value number. The LiveRanges in RHS are 471/// allowed to overlap with LiveRanges in the current interval, but only if 472/// the overlapping LiveRanges have the specified value number. 473void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS, 474 VNInfo *LHSValNo) { 475 // TODO: Make this more efficient. 476 iterator InsertPos = begin(); 477 for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { 478 // Map the valno in the other live range to the current live range. 479 LiveRange Tmp = *I; 480 Tmp.valno = LHSValNo; 481 InsertPos = addRangeFrom(Tmp, InsertPos); 482 } 483} 484 485 486/// MergeValueInAsValue - Merge all of the live ranges of a specific val# 487/// in RHS into this live interval as the specified value number. 488/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the 489/// current interval, it will replace the value numbers of the overlaped 490/// live ranges with the specified value number. 491void LiveInterval::MergeValueInAsValue(const LiveInterval &RHS, 492 const VNInfo *RHSValNo, VNInfo *LHSValNo) { 493 SmallVector<VNInfo*, 4> ReplacedValNos; 494 iterator IP = begin(); 495 for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { 496 if (I->valno != RHSValNo) 497 continue; 498 unsigned Start = I->start, End = I->end; 499 IP = std::upper_bound(IP, end(), Start); 500 // If the start of this range overlaps with an existing liverange, trim it. 501 if (IP != begin() && IP[-1].end > Start) { 502 if (IP[-1].valno != LHSValNo) { 503 ReplacedValNos.push_back(IP[-1].valno); 504 IP[-1].valno = LHSValNo; // Update val#. 505 } 506 Start = IP[-1].end; 507 // Trimmed away the whole range? 508 if (Start >= End) continue; 509 } 510 // If the end of this range overlaps with an existing liverange, trim it. 511 if (IP != end() && End > IP->start) { 512 if (IP->valno != LHSValNo) { 513 ReplacedValNos.push_back(IP->valno); 514 IP->valno = LHSValNo; // Update val#. 515 } 516 End = IP->start; 517 // If this trimmed away the whole range, ignore it. 518 if (Start == End) continue; 519 } 520 521 // Map the valno in the other live range to the current live range. 522 IP = addRangeFrom(LiveRange(Start, End, LHSValNo), IP); 523 } 524 525 526 SmallSet<VNInfo*, 4> Seen; 527 for (unsigned i = 0, e = ReplacedValNos.size(); i != e; ++i) { 528 VNInfo *V1 = ReplacedValNos[i]; 529 if (Seen.insert(V1)) { 530 bool isDead = true; 531 for (const_iterator I = begin(), E = end(); I != E; ++I) 532 if (I->valno == V1) { 533 isDead = false; 534 break; 535 } 536 if (isDead) { 537 // Now that V1 is dead, remove it. If it is the largest value number, 538 // just nuke it (and any other deleted values neighboring it), otherwise 539 // mark it as ~1U so it can be nuked later. 540 if (V1->id == getNumValNums()-1) { 541 do { 542 VNInfo *VNI = valnos.back(); 543 valnos.pop_back(); 544 VNI->~VNInfo(); 545 } while (!valnos.empty() && valnos.back()->def == ~1U); 546 } else { 547 V1->def = ~1U; 548 } 549 } 550 } 551 } 552} 553 554VNInfo *LiveInterval::getUnknownValNo(BumpPtrAllocator &VNInfoAllocator) { 555 unsigned i = getNumValNums(); 556 if (i) { 557 do { 558 --i; 559 VNInfo *VNI = getValNumInfo(i); 560 if (VNI->def == ~0U && !VNI->copy && 561 !VNI->hasPHIKill && !VNI->redefByEC && VNI->kills.empty()) 562 return VNI; 563 } while (i != 0); 564 } 565 return getNextValue(~0U, 0, VNInfoAllocator); 566} 567 568 569/// MergeInClobberRanges - For any live ranges that are not defined in the 570/// current interval, but are defined in the Clobbers interval, mark them 571/// used with an unknown definition value. 572void LiveInterval::MergeInClobberRanges(const LiveInterval &Clobbers, 573 BumpPtrAllocator &VNInfoAllocator) { 574 if (Clobbers.empty()) return; 575 576 // Find a value # to use for the clobber ranges. If there is already a value# 577 // for unknown values, use it. 578 VNInfo *ClobberValNo = getUnknownValNo(VNInfoAllocator); 579 580 iterator IP = begin(); 581 for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) { 582 bool Done = false; 583 unsigned Start = I->start, End = I->end; 584 // If a clobber range starts before an existing range and ends after 585 // it, the clobber range will need to be split into multiple ranges. 586 // Loop until the entire clobber range is handled. 587 while (!Done) { 588 Done = true; 589 IP = std::upper_bound(IP, end(), Start); 590 unsigned SubRangeStart = Start; 591 unsigned SubRangeEnd = End; 592 593 // If the start of this range overlaps with an existing liverange, trim it. 594 if (IP != begin() && IP[-1].end > SubRangeStart) { 595 SubRangeStart = IP[-1].end; 596 // Trimmed away the whole range? 597 if (SubRangeStart >= SubRangeEnd) continue; 598 } 599 // If the end of this range overlaps with an existing liverange, trim it. 600 if (IP != end() && SubRangeEnd > IP->start) { 601 // If the clobber live range extends beyond the existing live range, 602 // it'll need at least another live range, so set the flag to keep 603 // iterating. 604 if (SubRangeEnd > IP->end) { 605 Start = IP->end; 606 Done = false; 607 } 608 SubRangeEnd = IP->start; 609 // If this trimmed away the whole range, ignore it. 610 if (SubRangeStart == SubRangeEnd) continue; 611 } 612 613 // Insert the clobber interval. 614 IP = addRangeFrom(LiveRange(SubRangeStart, SubRangeEnd, ClobberValNo), 615 IP); 616 } 617 } 618} 619 620void LiveInterval::MergeInClobberRange(unsigned Start, unsigned End, 621 BumpPtrAllocator &VNInfoAllocator) { 622 // Find a value # to use for the clobber ranges. If there is already a value# 623 // for unknown values, use it. 624 VNInfo *ClobberValNo = getUnknownValNo(VNInfoAllocator); 625 626 iterator IP = begin(); 627 IP = std::upper_bound(IP, end(), Start); 628 629 // If the start of this range overlaps with an existing liverange, trim it. 630 if (IP != begin() && IP[-1].end > Start) { 631 Start = IP[-1].end; 632 // Trimmed away the whole range? 633 if (Start >= End) return; 634 } 635 // If the end of this range overlaps with an existing liverange, trim it. 636 if (IP != end() && End > IP->start) { 637 End = IP->start; 638 // If this trimmed away the whole range, ignore it. 639 if (Start == End) return; 640 } 641 642 // Insert the clobber interval. 643 addRangeFrom(LiveRange(Start, End, ClobberValNo), IP); 644} 645 646/// MergeValueNumberInto - This method is called when two value nubmers 647/// are found to be equivalent. This eliminates V1, replacing all 648/// LiveRanges with the V1 value number with the V2 value number. This can 649/// cause merging of V1/V2 values numbers and compaction of the value space. 650VNInfo* LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) { 651 assert(V1 != V2 && "Identical value#'s are always equivalent!"); 652 653 // This code actually merges the (numerically) larger value number into the 654 // smaller value number, which is likely to allow us to compactify the value 655 // space. The only thing we have to be careful of is to preserve the 656 // instruction that defines the result value. 657 658 // Make sure V2 is smaller than V1. 659 if (V1->id < V2->id) { 660 copyValNumInfo(V1, V2); 661 std::swap(V1, V2); 662 } 663 664 // Merge V1 live ranges into V2. 665 for (iterator I = begin(); I != end(); ) { 666 iterator LR = I++; 667 if (LR->valno != V1) continue; // Not a V1 LiveRange. 668 669 // Okay, we found a V1 live range. If it had a previous, touching, V2 live 670 // range, extend it. 671 if (LR != begin()) { 672 iterator Prev = LR-1; 673 if (Prev->valno == V2 && Prev->end == LR->start) { 674 Prev->end = LR->end; 675 676 // Erase this live-range. 677 ranges.erase(LR); 678 I = Prev+1; 679 LR = Prev; 680 } 681 } 682 683 // Okay, now we have a V1 or V2 live range that is maximally merged forward. 684 // Ensure that it is a V2 live-range. 685 LR->valno = V2; 686 687 // If we can merge it into later V2 live ranges, do so now. We ignore any 688 // following V1 live ranges, as they will be merged in subsequent iterations 689 // of the loop. 690 if (I != end()) { 691 if (I->start == LR->end && I->valno == V2) { 692 LR->end = I->end; 693 ranges.erase(I); 694 I = LR+1; 695 } 696 } 697 } 698 699 // Now that V1 is dead, remove it. If it is the largest value number, just 700 // nuke it (and any other deleted values neighboring it), otherwise mark it as 701 // ~1U so it can be nuked later. 702 if (V1->id == getNumValNums()-1) { 703 do { 704 VNInfo *VNI = valnos.back(); 705 valnos.pop_back(); 706 VNI->~VNInfo(); 707 } while (valnos.back()->def == ~1U); 708 } else { 709 V1->def = ~1U; 710 } 711 712 return V2; 713} 714 715void LiveInterval::Copy(const LiveInterval &RHS, 716 BumpPtrAllocator &VNInfoAllocator) { 717 ranges.clear(); 718 valnos.clear(); 719 preference = RHS.preference; 720 weight = RHS.weight; 721 for (unsigned i = 0, e = RHS.getNumValNums(); i != e; ++i) { 722 const VNInfo *VNI = RHS.getValNumInfo(i); 723 VNInfo *NewVNI = getNextValue(~0U, 0, VNInfoAllocator); 724 copyValNumInfo(NewVNI, VNI); 725 } 726 for (unsigned i = 0, e = RHS.ranges.size(); i != e; ++i) { 727 const LiveRange &LR = RHS.ranges[i]; 728 addRange(LiveRange(LR.start, LR.end, getValNumInfo(LR.valno->id))); 729 } 730} 731 732unsigned LiveInterval::getSize() const { 733 unsigned Sum = 0; 734 for (const_iterator I = begin(), E = end(); I != E; ++I) 735 Sum += I->end - I->start; 736 return Sum; 737} 738 739std::ostream& llvm::operator<<(std::ostream& os, const LiveRange &LR) { 740 return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")"; 741} 742 743void LiveRange::dump() const { 744 cerr << *this << "\n"; 745} 746 747void LiveInterval::print(std::ostream &OS, 748 const TargetRegisterInfo *TRI) const { 749 if (isStackSlot()) 750 OS << "SS#" << getStackSlotIndex(); 751 else if (TRI && TargetRegisterInfo::isPhysicalRegister(reg)) 752 OS << TRI->getName(reg); 753 else 754 OS << "%reg" << reg; 755 756 OS << ',' << weight; 757 758 if (empty()) 759 OS << " EMPTY"; 760 else { 761 OS << " = "; 762 for (LiveInterval::Ranges::const_iterator I = ranges.begin(), 763 E = ranges.end(); I != E; ++I) 764 OS << *I; 765 } 766 767 // Print value number info. 768 if (getNumValNums()) { 769 OS << " "; 770 unsigned vnum = 0; 771 for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e; 772 ++i, ++vnum) { 773 const VNInfo *vni = *i; 774 if (vnum) OS << " "; 775 OS << vnum << "@"; 776 if (vni->def == ~1U) { 777 OS << "x"; 778 } else { 779 if (vni->def == ~0U) 780 OS << "?"; 781 else 782 OS << vni->def; 783 unsigned ee = vni->kills.size(); 784 if (ee || vni->hasPHIKill) { 785 OS << "-("; 786 for (unsigned j = 0; j != ee; ++j) { 787 OS << vni->kills[j]; 788 if (j != ee-1) 789 OS << " "; 790 } 791 if (vni->hasPHIKill) { 792 if (ee) 793 OS << " "; 794 OS << "phi"; 795 } 796 OS << ")"; 797 } 798 } 799 } 800 } 801} 802 803void LiveInterval::dump() const { 804 cerr << *this << "\n"; 805} 806 807 808void LiveRange::print(std::ostream &os) const { 809 os << *this; 810} 811