1 //===- CodeGenRegisters.cpp - Register and RegisterClass Info -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines structures to encapsulate information gleaned from the
11 // target register and register class definitions.
13 //===----------------------------------------------------------------------===//
15 #include "CodeGenRegisters.h"
16 #include "CodeGenTarget.h"
17 #include "llvm/ADT/IntEqClasses.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/StringExtras.h"
21 #include "llvm/ADT/Twine.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/TableGen/Error.h"
27 #define DEBUG_TYPE "regalloc-emitter"
29 //===----------------------------------------------------------------------===//
31 //===----------------------------------------------------------------------===//
33 CodeGenSubRegIndex::CodeGenSubRegIndex(Record *R, unsigned Enum)
34 : TheDef(R), EnumValue(Enum), LaneMask(0), AllSuperRegsCovered(true) {
36 if (R->getValue("Namespace"))
37 Namespace = R->getValueAsString("Namespace");
38 Size = R->getValueAsInt("Size");
39 Offset = R->getValueAsInt("Offset");
42 CodeGenSubRegIndex::CodeGenSubRegIndex(StringRef N, StringRef Nspace,
44 : TheDef(nullptr), Name(N), Namespace(Nspace), Size(-1), Offset(-1),
45 EnumValue(Enum), LaneMask(0), AllSuperRegsCovered(true) {
48 std::string CodeGenSubRegIndex::getQualifiedName() const {
49 std::string N = getNamespace();
56 void CodeGenSubRegIndex::updateComponents(CodeGenRegBank &RegBank) {
60 std::vector<Record*> Comps = TheDef->getValueAsListOfDefs("ComposedOf");
62 if (Comps.size() != 2)
63 PrintFatalError(TheDef->getLoc(),
64 "ComposedOf must have exactly two entries");
65 CodeGenSubRegIndex *A = RegBank.getSubRegIdx(Comps[0]);
66 CodeGenSubRegIndex *B = RegBank.getSubRegIdx(Comps[1]);
67 CodeGenSubRegIndex *X = A->addComposite(B, this);
69 PrintFatalError(TheDef->getLoc(), "Ambiguous ComposedOf entries");
72 std::vector<Record*> Parts =
73 TheDef->getValueAsListOfDefs("CoveringSubRegIndices");
76 PrintFatalError(TheDef->getLoc(),
77 "CoveredBySubRegs must have two or more entries");
78 SmallVector<CodeGenSubRegIndex*, 8> IdxParts;
79 for (unsigned i = 0, e = Parts.size(); i != e; ++i)
80 IdxParts.push_back(RegBank.getSubRegIdx(Parts[i]));
81 RegBank.addConcatSubRegIndex(IdxParts, this);
85 unsigned CodeGenSubRegIndex::computeLaneMask() const {
90 // Recursion guard, shouldn't be required.
93 // The lane mask is simply the union of all sub-indices.
95 for (const auto &C : Composed)
96 M |= C.second->computeLaneMask();
97 assert(M && "Missing lane mask, sub-register cycle?");
102 //===----------------------------------------------------------------------===//
104 //===----------------------------------------------------------------------===//
106 CodeGenRegister::CodeGenRegister(Record *R, unsigned Enum)
109 CostPerUse(R->getValueAsInt("CostPerUse")),
110 CoveredBySubRegs(R->getValueAsBit("CoveredBySubRegs")),
111 NumNativeRegUnits(0),
112 SubRegsComplete(false),
113 SuperRegsComplete(false),
117 void CodeGenRegister::buildObjectGraph(CodeGenRegBank &RegBank) {
118 std::vector<Record*> SRIs = TheDef->getValueAsListOfDefs("SubRegIndices");
119 std::vector<Record*> SRs = TheDef->getValueAsListOfDefs("SubRegs");
121 if (SRIs.size() != SRs.size())
122 PrintFatalError(TheDef->getLoc(),
123 "SubRegs and SubRegIndices must have the same size");
125 for (unsigned i = 0, e = SRIs.size(); i != e; ++i) {
126 ExplicitSubRegIndices.push_back(RegBank.getSubRegIdx(SRIs[i]));
127 ExplicitSubRegs.push_back(RegBank.getReg(SRs[i]));
130 // Also compute leading super-registers. Each register has a list of
131 // covered-by-subregs super-registers where it appears as the first explicit
134 // This is used by computeSecondarySubRegs() to find candidates.
135 if (CoveredBySubRegs && !ExplicitSubRegs.empty())
136 ExplicitSubRegs.front()->LeadingSuperRegs.push_back(this);
138 // Add ad hoc alias links. This is a symmetric relationship between two
139 // registers, so build a symmetric graph by adding links in both ends.
140 std::vector<Record*> Aliases = TheDef->getValueAsListOfDefs("Aliases");
141 for (unsigned i = 0, e = Aliases.size(); i != e; ++i) {
142 CodeGenRegister *Reg = RegBank.getReg(Aliases[i]);
143 ExplicitAliases.push_back(Reg);
144 Reg->ExplicitAliases.push_back(this);
148 const std::string &CodeGenRegister::getName() const {
149 return TheDef->getName();
153 // Iterate over all register units in a set of registers.
154 class RegUnitIterator {
155 CodeGenRegister::Set::const_iterator RegI, RegE;
156 CodeGenRegister::RegUnitList::const_iterator UnitI, UnitE;
159 RegUnitIterator(const CodeGenRegister::Set &Regs):
160 RegI(Regs.begin()), RegE(Regs.end()), UnitI(), UnitE() {
163 UnitI = (*RegI)->getRegUnits().begin();
164 UnitE = (*RegI)->getRegUnits().end();
169 bool isValid() const { return UnitI != UnitE; }
171 unsigned operator* () const { assert(isValid()); return *UnitI; }
173 const CodeGenRegister *getReg() const { assert(isValid()); return *RegI; }
175 /// Preincrement. Move to the next unit.
177 assert(isValid() && "Cannot advance beyond the last operand");
184 while (UnitI == UnitE) {
187 UnitI = (*RegI)->getRegUnits().begin();
188 UnitE = (*RegI)->getRegUnits().end();
194 // Merge two RegUnitLists maintaining the order and removing duplicates.
195 // Overwrites MergedRU in the process.
196 static void mergeRegUnits(CodeGenRegister::RegUnitList &MergedRU,
197 const CodeGenRegister::RegUnitList &RRU) {
198 CodeGenRegister::RegUnitList LRU = MergedRU;
200 std::set_union(LRU.begin(), LRU.end(), RRU.begin(), RRU.end(),
201 std::back_inserter(MergedRU));
204 // Return true of this unit appears in RegUnits.
205 static bool hasRegUnit(CodeGenRegister::RegUnitList &RegUnits, unsigned Unit) {
206 return std::count(RegUnits.begin(), RegUnits.end(), Unit);
209 // Inherit register units from subregisters.
210 // Return true if the RegUnits changed.
211 bool CodeGenRegister::inheritRegUnits(CodeGenRegBank &RegBank) {
212 unsigned OldNumUnits = RegUnits.size();
213 for (SubRegMap::const_iterator I = SubRegs.begin(), E = SubRegs.end();
215 CodeGenRegister *SR = I->second;
216 // Merge the subregister's units into this register's RegUnits.
217 mergeRegUnits(RegUnits, SR->RegUnits);
219 return OldNumUnits != RegUnits.size();
222 const CodeGenRegister::SubRegMap &
223 CodeGenRegister::computeSubRegs(CodeGenRegBank &RegBank) {
224 // Only compute this map once.
227 SubRegsComplete = true;
229 // First insert the explicit subregs and make sure they are fully indexed.
230 for (unsigned i = 0, e = ExplicitSubRegs.size(); i != e; ++i) {
231 CodeGenRegister *SR = ExplicitSubRegs[i];
232 CodeGenSubRegIndex *Idx = ExplicitSubRegIndices[i];
233 if (!SubRegs.insert(std::make_pair(Idx, SR)).second)
234 PrintFatalError(TheDef->getLoc(), "SubRegIndex " + Idx->getName() +
235 " appears twice in Register " + getName());
236 // Map explicit sub-registers first, so the names take precedence.
237 // The inherited sub-registers are mapped below.
238 SubReg2Idx.insert(std::make_pair(SR, Idx));
241 // Keep track of inherited subregs and how they can be reached.
242 SmallPtrSet<CodeGenRegister*, 8> Orphans;
244 // Clone inherited subregs and place duplicate entries in Orphans.
245 // Here the order is important - earlier subregs take precedence.
246 for (unsigned i = 0, e = ExplicitSubRegs.size(); i != e; ++i) {
247 CodeGenRegister *SR = ExplicitSubRegs[i];
248 const SubRegMap &Map = SR->computeSubRegs(RegBank);
250 for (SubRegMap::const_iterator SI = Map.begin(), SE = Map.end(); SI != SE;
252 if (!SubRegs.insert(*SI).second)
253 Orphans.insert(SI->second);
257 // Expand any composed subreg indices.
258 // If dsub_2 has ComposedOf = [qsub_1, dsub_0], and this register has a
259 // qsub_1 subreg, add a dsub_2 subreg. Keep growing Indices and process
260 // expanded subreg indices recursively.
261 SmallVector<CodeGenSubRegIndex*, 8> Indices = ExplicitSubRegIndices;
262 for (unsigned i = 0; i != Indices.size(); ++i) {
263 CodeGenSubRegIndex *Idx = Indices[i];
264 const CodeGenSubRegIndex::CompMap &Comps = Idx->getComposites();
265 CodeGenRegister *SR = SubRegs[Idx];
266 const SubRegMap &Map = SR->computeSubRegs(RegBank);
268 // Look at the possible compositions of Idx.
269 // They may not all be supported by SR.
270 for (CodeGenSubRegIndex::CompMap::const_iterator I = Comps.begin(),
271 E = Comps.end(); I != E; ++I) {
272 SubRegMap::const_iterator SRI = Map.find(I->first);
273 if (SRI == Map.end())
274 continue; // Idx + I->first doesn't exist in SR.
275 // Add I->second as a name for the subreg SRI->second, assuming it is
276 // orphaned, and the name isn't already used for something else.
277 if (SubRegs.count(I->second) || !Orphans.erase(SRI->second))
279 // We found a new name for the orphaned sub-register.
280 SubRegs.insert(std::make_pair(I->second, SRI->second));
281 Indices.push_back(I->second);
285 // Now Orphans contains the inherited subregisters without a direct index.
286 // Create inferred indexes for all missing entries.
287 // Work backwards in the Indices vector in order to compose subregs bottom-up.
288 // Consider this subreg sequence:
290 // qsub_1 -> dsub_0 -> ssub_0
292 // The qsub_1 -> dsub_0 composition becomes dsub_2, so the ssub_0 register
293 // can be reached in two different ways:
298 // We pick the latter composition because another register may have [dsub_0,
299 // dsub_1, dsub_2] subregs without necessarily having a qsub_1 subreg. The
300 // dsub_2 -> ssub_0 composition can be shared.
301 while (!Indices.empty() && !Orphans.empty()) {
302 CodeGenSubRegIndex *Idx = Indices.pop_back_val();
303 CodeGenRegister *SR = SubRegs[Idx];
304 const SubRegMap &Map = SR->computeSubRegs(RegBank);
305 for (SubRegMap::const_iterator SI = Map.begin(), SE = Map.end(); SI != SE;
307 if (Orphans.erase(SI->second))
308 SubRegs[RegBank.getCompositeSubRegIndex(Idx, SI->first)] = SI->second;
311 // Compute the inverse SubReg -> Idx map.
312 for (SubRegMap::const_iterator SI = SubRegs.begin(), SE = SubRegs.end();
314 if (SI->second == this) {
317 Loc = TheDef->getLoc();
318 PrintFatalError(Loc, "Register " + getName() +
319 " has itself as a sub-register");
322 // Compute AllSuperRegsCovered.
323 if (!CoveredBySubRegs)
324 SI->first->AllSuperRegsCovered = false;
326 // Ensure that every sub-register has a unique name.
327 DenseMap<const CodeGenRegister*, CodeGenSubRegIndex*>::iterator Ins =
328 SubReg2Idx.insert(std::make_pair(SI->second, SI->first)).first;
329 if (Ins->second == SI->first)
331 // Trouble: Two different names for SI->second.
334 Loc = TheDef->getLoc();
335 PrintFatalError(Loc, "Sub-register can't have two names: " +
336 SI->second->getName() + " available as " +
337 SI->first->getName() + " and " + Ins->second->getName());
340 // Derive possible names for sub-register concatenations from any explicit
341 // sub-registers. By doing this before computeSecondarySubRegs(), we ensure
342 // that getConcatSubRegIndex() won't invent any concatenated indices that the
343 // user already specified.
344 for (unsigned i = 0, e = ExplicitSubRegs.size(); i != e; ++i) {
345 CodeGenRegister *SR = ExplicitSubRegs[i];
346 if (!SR->CoveredBySubRegs || SR->ExplicitSubRegs.size() <= 1)
349 // SR is composed of multiple sub-regs. Find their names in this register.
350 SmallVector<CodeGenSubRegIndex*, 8> Parts;
351 for (unsigned j = 0, e = SR->ExplicitSubRegs.size(); j != e; ++j)
352 Parts.push_back(getSubRegIndex(SR->ExplicitSubRegs[j]));
354 // Offer this as an existing spelling for the concatenation of Parts.
355 RegBank.addConcatSubRegIndex(Parts, ExplicitSubRegIndices[i]);
358 // Initialize RegUnitList. Because getSubRegs is called recursively, this
359 // processes the register hierarchy in postorder.
361 // Inherit all sub-register units. It is good enough to look at the explicit
362 // sub-registers, the other registers won't contribute any more units.
363 for (unsigned i = 0, e = ExplicitSubRegs.size(); i != e; ++i) {
364 CodeGenRegister *SR = ExplicitSubRegs[i];
365 // Explicit sub-registers are usually disjoint, so this is a good way of
366 // computing the union. We may pick up a few duplicates that will be
368 unsigned N = RegUnits.size();
369 RegUnits.append(SR->RegUnits.begin(), SR->RegUnits.end());
370 std::inplace_merge(RegUnits.begin(), RegUnits.begin() + N, RegUnits.end());
372 RegUnits.erase(std::unique(RegUnits.begin(), RegUnits.end()), RegUnits.end());
374 // Absent any ad hoc aliasing, we create one register unit per leaf register.
375 // These units correspond to the maximal cliques in the register overlap
376 // graph which is optimal.
378 // When there is ad hoc aliasing, we simply create one unit per edge in the
379 // undirected ad hoc aliasing graph. Technically, we could do better by
380 // identifying maximal cliques in the ad hoc graph, but cliques larger than 2
381 // are extremely rare anyway (I've never seen one), so we don't bother with
382 // the added complexity.
383 for (unsigned i = 0, e = ExplicitAliases.size(); i != e; ++i) {
384 CodeGenRegister *AR = ExplicitAliases[i];
385 // Only visit each edge once.
386 if (AR->SubRegsComplete)
388 // Create a RegUnit representing this alias edge, and add it to both
390 unsigned Unit = RegBank.newRegUnit(this, AR);
391 RegUnits.push_back(Unit);
392 AR->RegUnits.push_back(Unit);
395 // Finally, create units for leaf registers without ad hoc aliases. Note that
396 // a leaf register with ad hoc aliases doesn't get its own unit - it isn't
397 // necessary. This means the aliasing leaf registers can share a single unit.
398 if (RegUnits.empty())
399 RegUnits.push_back(RegBank.newRegUnit(this));
401 // We have now computed the native register units. More may be adopted later
402 // for balancing purposes.
403 NumNativeRegUnits = RegUnits.size();
408 // In a register that is covered by its sub-registers, try to find redundant
409 // sub-registers. For example:
415 // We can infer that D1_D2 is also a sub-register, even if it wasn't named in
416 // the register definition.
418 // The explicitly specified registers form a tree. This function discovers
419 // sub-register relationships that would force a DAG.
421 void CodeGenRegister::computeSecondarySubRegs(CodeGenRegBank &RegBank) {
422 // Collect new sub-registers first, add them later.
423 SmallVector<SubRegMap::value_type, 8> NewSubRegs;
425 // Look at the leading super-registers of each sub-register. Those are the
426 // candidates for new sub-registers, assuming they are fully contained in
428 for (SubRegMap::iterator I = SubRegs.begin(), E = SubRegs.end(); I != E; ++I){
429 const CodeGenRegister *SubReg = I->second;
430 const CodeGenRegister::SuperRegList &Leads = SubReg->LeadingSuperRegs;
431 for (unsigned i = 0, e = Leads.size(); i != e; ++i) {
432 CodeGenRegister *Cand = const_cast<CodeGenRegister*>(Leads[i]);
433 // Already got this sub-register?
434 if (Cand == this || getSubRegIndex(Cand))
436 // Check if each component of Cand is already a sub-register.
437 // We know that the first component is I->second, and is present with the
439 SmallVector<CodeGenSubRegIndex*, 8> Parts(1, I->first);
440 assert(!Cand->ExplicitSubRegs.empty() &&
441 "Super-register has no sub-registers");
442 for (unsigned j = 1, e = Cand->ExplicitSubRegs.size(); j != e; ++j) {
443 if (CodeGenSubRegIndex *Idx = getSubRegIndex(Cand->ExplicitSubRegs[j]))
444 Parts.push_back(Idx);
446 // Sub-register doesn't exist.
451 // If some Cand sub-register is not part of this register, or if Cand only
452 // has one sub-register, there is nothing to do.
453 if (Parts.size() <= 1)
456 // Each part of Cand is a sub-register of this. Make the full Cand also
457 // a sub-register with a concatenated sub-register index.
458 CodeGenSubRegIndex *Concat= RegBank.getConcatSubRegIndex(Parts);
459 NewSubRegs.push_back(std::make_pair(Concat, Cand));
463 // Now add all the new sub-registers.
464 for (unsigned i = 0, e = NewSubRegs.size(); i != e; ++i) {
465 // Don't add Cand if another sub-register is already using the index.
466 if (!SubRegs.insert(NewSubRegs[i]).second)
469 CodeGenSubRegIndex *NewIdx = NewSubRegs[i].first;
470 CodeGenRegister *NewSubReg = NewSubRegs[i].second;
471 SubReg2Idx.insert(std::make_pair(NewSubReg, NewIdx));
474 // Create sub-register index composition maps for the synthesized indices.
475 for (unsigned i = 0, e = NewSubRegs.size(); i != e; ++i) {
476 CodeGenSubRegIndex *NewIdx = NewSubRegs[i].first;
477 CodeGenRegister *NewSubReg = NewSubRegs[i].second;
478 for (SubRegMap::const_iterator SI = NewSubReg->SubRegs.begin(),
479 SE = NewSubReg->SubRegs.end(); SI != SE; ++SI) {
480 CodeGenSubRegIndex *SubIdx = getSubRegIndex(SI->second);
482 PrintFatalError(TheDef->getLoc(), "No SubRegIndex for " +
483 SI->second->getName() + " in " + getName());
484 NewIdx->addComposite(SI->first, SubIdx);
489 void CodeGenRegister::computeSuperRegs(CodeGenRegBank &RegBank) {
490 // Only visit each register once.
491 if (SuperRegsComplete)
493 SuperRegsComplete = true;
495 // Make sure all sub-registers have been visited first, so the super-reg
496 // lists will be topologically ordered.
497 for (SubRegMap::const_iterator I = SubRegs.begin(), E = SubRegs.end();
499 I->second->computeSuperRegs(RegBank);
501 // Now add this as a super-register on all sub-registers.
502 // Also compute the TopoSigId in post-order.
504 for (SubRegMap::const_iterator I = SubRegs.begin(), E = SubRegs.end();
506 // Topological signature computed from SubIdx, TopoId(SubReg).
507 // Loops and idempotent indices have TopoSig = ~0u.
508 Id.push_back(I->first->EnumValue);
509 Id.push_back(I->second->TopoSig);
511 // Don't add duplicate entries.
512 if (!I->second->SuperRegs.empty() && I->second->SuperRegs.back() == this)
514 I->second->SuperRegs.push_back(this);
516 TopoSig = RegBank.getTopoSig(Id);
520 CodeGenRegister::addSubRegsPreOrder(SetVector<const CodeGenRegister*> &OSet,
521 CodeGenRegBank &RegBank) const {
522 assert(SubRegsComplete && "Must precompute sub-registers");
523 for (unsigned i = 0, e = ExplicitSubRegs.size(); i != e; ++i) {
524 CodeGenRegister *SR = ExplicitSubRegs[i];
526 SR->addSubRegsPreOrder(OSet, RegBank);
528 // Add any secondary sub-registers that weren't part of the explicit tree.
529 for (SubRegMap::const_iterator I = SubRegs.begin(), E = SubRegs.end();
531 OSet.insert(I->second);
534 // Get the sum of this register's unit weights.
535 unsigned CodeGenRegister::getWeight(const CodeGenRegBank &RegBank) const {
537 for (RegUnitList::const_iterator I = RegUnits.begin(), E = RegUnits.end();
539 Weight += RegBank.getRegUnit(*I).Weight;
544 //===----------------------------------------------------------------------===//
546 //===----------------------------------------------------------------------===//
548 // A RegisterTuples def is used to generate pseudo-registers from lists of
549 // sub-registers. We provide a SetTheory expander class that returns the new
552 struct TupleExpander : SetTheory::Expander {
553 void expand(SetTheory &ST, Record *Def, SetTheory::RecSet &Elts) override {
554 std::vector<Record*> Indices = Def->getValueAsListOfDefs("SubRegIndices");
555 unsigned Dim = Indices.size();
556 ListInit *SubRegs = Def->getValueAsListInit("SubRegs");
557 if (Dim != SubRegs->getSize())
558 PrintFatalError(Def->getLoc(), "SubRegIndices and SubRegs size mismatch");
560 PrintFatalError(Def->getLoc(),
561 "Tuples must have at least 2 sub-registers");
563 // Evaluate the sub-register lists to be zipped.
564 unsigned Length = ~0u;
565 SmallVector<SetTheory::RecSet, 4> Lists(Dim);
566 for (unsigned i = 0; i != Dim; ++i) {
567 ST.evaluate(SubRegs->getElement(i), Lists[i], Def->getLoc());
568 Length = std::min(Length, unsigned(Lists[i].size()));
574 // Precompute some types.
575 Record *RegisterCl = Def->getRecords().getClass("Register");
576 RecTy *RegisterRecTy = RecordRecTy::get(RegisterCl);
577 StringInit *BlankName = StringInit::get("");
580 for (unsigned n = 0; n != Length; ++n) {
582 Record *Proto = Lists[0][n];
583 std::vector<Init*> Tuple;
584 unsigned CostPerUse = 0;
585 for (unsigned i = 0; i != Dim; ++i) {
586 Record *Reg = Lists[i][n];
588 Name += Reg->getName();
589 Tuple.push_back(DefInit::get(Reg));
590 CostPerUse = std::max(CostPerUse,
591 unsigned(Reg->getValueAsInt("CostPerUse")));
594 // Create a new Record representing the synthesized register. This record
595 // is only for consumption by CodeGenRegister, it is not added to the
597 Record *NewReg = new Record(Name, Def->getLoc(), Def->getRecords());
600 // Copy Proto super-classes.
601 ArrayRef<Record *> Supers = Proto->getSuperClasses();
602 ArrayRef<SMRange> Ranges = Proto->getSuperClassRanges();
603 for (unsigned i = 0, e = Supers.size(); i != e; ++i)
604 NewReg->addSuperClass(Supers[i], Ranges[i]);
606 // Copy Proto fields.
607 for (unsigned i = 0, e = Proto->getValues().size(); i != e; ++i) {
608 RecordVal RV = Proto->getValues()[i];
610 // Skip existing fields, like NAME.
611 if (NewReg->getValue(RV.getNameInit()))
614 StringRef Field = RV.getName();
616 // Replace the sub-register list with Tuple.
617 if (Field == "SubRegs")
618 RV.setValue(ListInit::get(Tuple, RegisterRecTy));
620 // Provide a blank AsmName. MC hacks are required anyway.
621 if (Field == "AsmName")
622 RV.setValue(BlankName);
624 // CostPerUse is aggregated from all Tuple members.
625 if (Field == "CostPerUse")
626 RV.setValue(IntInit::get(CostPerUse));
628 // Composite registers are always covered by sub-registers.
629 if (Field == "CoveredBySubRegs")
630 RV.setValue(BitInit::get(true));
632 // Copy fields from the RegisterTuples def.
633 if (Field == "SubRegIndices" ||
634 Field == "CompositeIndices") {
635 NewReg->addValue(*Def->getValue(Field));
639 // Some fields get their default uninitialized value.
640 if (Field == "DwarfNumbers" ||
641 Field == "DwarfAlias" ||
642 Field == "Aliases") {
643 if (const RecordVal *DefRV = RegisterCl->getValue(Field))
644 NewReg->addValue(*DefRV);
648 // Everything else is copied from Proto.
649 NewReg->addValue(RV);
656 //===----------------------------------------------------------------------===//
657 // CodeGenRegisterClass
658 //===----------------------------------------------------------------------===//
660 CodeGenRegisterClass::CodeGenRegisterClass(CodeGenRegBank &RegBank, Record *R)
663 TopoSigs(RegBank.getNumTopoSigs()),
665 // Rename anonymous register classes.
666 if (R->getName().size() > 9 && R->getName()[9] == '.') {
667 static unsigned AnonCounter = 0;
668 R->setName("AnonRegClass_" + utostr(AnonCounter));
669 // MSVC2012 ICEs if AnonCounter++ is directly passed to utostr.
673 std::vector<Record*> TypeList = R->getValueAsListOfDefs("RegTypes");
674 for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
675 Record *Type = TypeList[i];
676 if (!Type->isSubClassOf("ValueType"))
677 PrintFatalError("RegTypes list member '" + Type->getName() +
678 "' does not derive from the ValueType class!");
679 VTs.push_back(getValueType(Type));
681 assert(!VTs.empty() && "RegisterClass must contain at least one ValueType!");
683 // Allocation order 0 is the full set. AltOrders provides others.
684 const SetTheory::RecVec *Elements = RegBank.getSets().expand(R);
685 ListInit *AltOrders = R->getValueAsListInit("AltOrders");
686 Orders.resize(1 + AltOrders->size());
688 // Default allocation order always contains all registers.
689 for (unsigned i = 0, e = Elements->size(); i != e; ++i) {
690 Orders[0].push_back((*Elements)[i]);
691 const CodeGenRegister *Reg = RegBank.getReg((*Elements)[i]);
693 TopoSigs.set(Reg->getTopoSig());
696 // Alternative allocation orders may be subsets.
697 SetTheory::RecSet Order;
698 for (unsigned i = 0, e = AltOrders->size(); i != e; ++i) {
699 RegBank.getSets().evaluate(AltOrders->getElement(i), Order, R->getLoc());
700 Orders[1 + i].append(Order.begin(), Order.end());
701 // Verify that all altorder members are regclass members.
702 while (!Order.empty()) {
703 CodeGenRegister *Reg = RegBank.getReg(Order.back());
706 PrintFatalError(R->getLoc(), " AltOrder register " + Reg->getName() +
707 " is not a class member");
711 // Allow targets to override the size in bits of the RegisterClass.
712 unsigned Size = R->getValueAsInt("Size");
714 Namespace = R->getValueAsString("Namespace");
715 SpillSize = Size ? Size : MVT(VTs[0]).getSizeInBits();
716 SpillAlignment = R->getValueAsInt("Alignment");
717 CopyCost = R->getValueAsInt("CopyCost");
718 Allocatable = R->getValueAsBit("isAllocatable");
719 AltOrderSelect = R->getValueAsString("AltOrderSelect");
722 // Create an inferred register class that was missing from the .td files.
723 // Most properties will be inherited from the closest super-class after the
724 // class structure has been computed.
725 CodeGenRegisterClass::CodeGenRegisterClass(CodeGenRegBank &RegBank,
726 StringRef Name, Key Props)
727 : Members(*Props.Members),
730 TopoSigs(RegBank.getNumTopoSigs()),
732 SpillSize(Props.SpillSize),
733 SpillAlignment(Props.SpillAlignment),
736 for (CodeGenRegister::Set::iterator I = Members.begin(), E = Members.end();
738 TopoSigs.set((*I)->getTopoSig());
741 // Compute inherited propertied for a synthesized register class.
742 void CodeGenRegisterClass::inheritProperties(CodeGenRegBank &RegBank) {
743 assert(!getDef() && "Only synthesized classes can inherit properties");
744 assert(!SuperClasses.empty() && "Synthesized class without super class");
746 // The last super-class is the smallest one.
747 CodeGenRegisterClass &Super = *SuperClasses.back();
749 // Most properties are copied directly.
750 // Exceptions are members, size, and alignment
751 Namespace = Super.Namespace;
753 CopyCost = Super.CopyCost;
754 Allocatable = Super.Allocatable;
755 AltOrderSelect = Super.AltOrderSelect;
757 // Copy all allocation orders, filter out foreign registers from the larger
759 Orders.resize(Super.Orders.size());
760 for (unsigned i = 0, ie = Super.Orders.size(); i != ie; ++i)
761 for (unsigned j = 0, je = Super.Orders[i].size(); j != je; ++j)
762 if (contains(RegBank.getReg(Super.Orders[i][j])))
763 Orders[i].push_back(Super.Orders[i][j]);
766 bool CodeGenRegisterClass::contains(const CodeGenRegister *Reg) const {
767 return Members.count(Reg);
771 raw_ostream &operator<<(raw_ostream &OS, const CodeGenRegisterClass::Key &K) {
772 OS << "{ S=" << K.SpillSize << ", A=" << K.SpillAlignment;
773 for (CodeGenRegister::Set::const_iterator I = K.Members->begin(),
774 E = K.Members->end(); I != E; ++I)
775 OS << ", " << (*I)->getName();
780 // This is a simple lexicographical order that can be used to search for sets.
781 // It is not the same as the topological order provided by TopoOrderRC.
782 bool CodeGenRegisterClass::Key::
783 operator<(const CodeGenRegisterClass::Key &B) const {
784 assert(Members && B.Members);
785 return std::tie(*Members, SpillSize, SpillAlignment) <
786 std::tie(*B.Members, B.SpillSize, B.SpillAlignment);
789 // Returns true if RC is a strict subclass.
790 // RC is a sub-class of this class if it is a valid replacement for any
791 // instruction operand where a register of this classis required. It must
792 // satisfy these conditions:
794 // 1. All RC registers are also in this.
795 // 2. The RC spill size must not be smaller than our spill size.
796 // 3. RC spill alignment must be compatible with ours.
798 static bool testSubClass(const CodeGenRegisterClass *A,
799 const CodeGenRegisterClass *B) {
800 return A->SpillAlignment && B->SpillAlignment % A->SpillAlignment == 0 &&
801 A->SpillSize <= B->SpillSize &&
802 std::includes(A->getMembers().begin(), A->getMembers().end(),
803 B->getMembers().begin(), B->getMembers().end(),
804 CodeGenRegister::Less());
807 /// Sorting predicate for register classes. This provides a topological
808 /// ordering that arranges all register classes before their sub-classes.
810 /// Register classes with the same registers, spill size, and alignment form a
811 /// clique. They will be ordered alphabetically.
813 static int TopoOrderRC(CodeGenRegisterClass *const *PA,
814 CodeGenRegisterClass *const *PB) {
815 const CodeGenRegisterClass *A = *PA;
816 const CodeGenRegisterClass *B = *PB;
820 // Order by ascending spill size.
821 if (A->SpillSize < B->SpillSize)
823 if (A->SpillSize > B->SpillSize)
826 // Order by ascending spill alignment.
827 if (A->SpillAlignment < B->SpillAlignment)
829 if (A->SpillAlignment > B->SpillAlignment)
832 // Order by descending set size. Note that the classes' allocation order may
833 // not have been computed yet. The Members set is always vaild.
834 if (A->getMembers().size() > B->getMembers().size())
836 if (A->getMembers().size() < B->getMembers().size())
839 // Finally order by name as a tie breaker.
840 return StringRef(A->getName()).compare(B->getName());
843 std::string CodeGenRegisterClass::getQualifiedName() const {
844 if (Namespace.empty())
847 return Namespace + "::" + getName();
850 // Compute sub-classes of all register classes.
851 // Assume the classes are ordered topologically.
852 void CodeGenRegisterClass::computeSubClasses(CodeGenRegBank &RegBank) {
853 ArrayRef<CodeGenRegisterClass*> RegClasses = RegBank.getRegClasses();
855 // Visit backwards so sub-classes are seen first.
856 for (unsigned rci = RegClasses.size(); rci; --rci) {
857 CodeGenRegisterClass &RC = *RegClasses[rci - 1];
858 RC.SubClasses.resize(RegClasses.size());
859 RC.SubClasses.set(RC.EnumValue);
861 // Normally, all subclasses have IDs >= rci, unless RC is part of a clique.
862 for (unsigned s = rci; s != RegClasses.size(); ++s) {
863 if (RC.SubClasses.test(s))
865 CodeGenRegisterClass *SubRC = RegClasses[s];
866 if (!testSubClass(&RC, SubRC))
868 // SubRC is a sub-class. Grap all its sub-classes so we won't have to
870 RC.SubClasses |= SubRC->SubClasses;
873 // Sweep up missed clique members. They will be immediately preceding RC.
874 for (unsigned s = rci - 1; s && testSubClass(&RC, RegClasses[s - 1]); --s)
875 RC.SubClasses.set(s - 1);
878 // Compute the SuperClasses lists from the SubClasses vectors.
879 for (unsigned rci = 0; rci != RegClasses.size(); ++rci) {
880 const BitVector &SC = RegClasses[rci]->getSubClasses();
881 for (int s = SC.find_first(); s >= 0; s = SC.find_next(s)) {
882 if (unsigned(s) == rci)
884 RegClasses[s]->SuperClasses.push_back(RegClasses[rci]);
888 // With the class hierarchy in place, let synthesized register classes inherit
889 // properties from their closest super-class. The iteration order here can
890 // propagate properties down multiple levels.
891 for (unsigned rci = 0; rci != RegClasses.size(); ++rci)
892 if (!RegClasses[rci]->getDef())
893 RegClasses[rci]->inheritProperties(RegBank);
896 void CodeGenRegisterClass::getSuperRegClasses(const CodeGenSubRegIndex *SubIdx,
897 BitVector &Out) const {
898 auto FindI = SuperRegClasses.find(SubIdx);
899 if (FindI == SuperRegClasses.end())
901 for (CodeGenRegisterClass *RC : FindI->second)
902 Out.set(RC->EnumValue);
905 // Populate a unique sorted list of units from a register set.
906 void CodeGenRegisterClass::buildRegUnitSet(
907 std::vector<unsigned> &RegUnits) const {
908 std::vector<unsigned> TmpUnits;
909 for (RegUnitIterator UnitI(Members); UnitI.isValid(); ++UnitI)
910 TmpUnits.push_back(*UnitI);
911 std::sort(TmpUnits.begin(), TmpUnits.end());
912 std::unique_copy(TmpUnits.begin(), TmpUnits.end(),
913 std::back_inserter(RegUnits));
916 //===----------------------------------------------------------------------===//
918 //===----------------------------------------------------------------------===//
920 CodeGenRegBank::CodeGenRegBank(RecordKeeper &Records) {
921 // Configure register Sets to understand register classes and tuples.
922 Sets.addFieldExpander("RegisterClass", "MemberList");
923 Sets.addFieldExpander("CalleeSavedRegs", "SaveList");
924 Sets.addExpander("RegisterTuples", new TupleExpander());
926 // Read in the user-defined (named) sub-register indices.
927 // More indices will be synthesized later.
928 std::vector<Record*> SRIs = Records.getAllDerivedDefinitions("SubRegIndex");
929 std::sort(SRIs.begin(), SRIs.end(), LessRecord());
930 for (unsigned i = 0, e = SRIs.size(); i != e; ++i)
931 getSubRegIdx(SRIs[i]);
932 // Build composite maps from ComposedOf fields.
933 for (auto &Idx : SubRegIndices)
934 Idx.updateComponents(*this);
936 // Read in the register definitions.
937 std::vector<Record*> Regs = Records.getAllDerivedDefinitions("Register");
938 std::sort(Regs.begin(), Regs.end(), LessRecordRegister());
939 // Assign the enumeration values.
940 for (unsigned i = 0, e = Regs.size(); i != e; ++i)
943 // Expand tuples and number the new registers.
944 std::vector<Record*> Tups =
945 Records.getAllDerivedDefinitions("RegisterTuples");
947 std::vector<Record*> TupRegsCopy;
948 for (unsigned i = 0, e = Tups.size(); i != e; ++i) {
949 const std::vector<Record*> *TupRegs = Sets.expand(Tups[i]);
950 TupRegsCopy.reserve(TupRegs->size());
951 TupRegsCopy.assign(TupRegs->begin(), TupRegs->end());
952 std::sort(TupRegsCopy.begin(), TupRegsCopy.end(), LessRecordRegister());
953 for (unsigned j = 0, je = TupRegsCopy.size(); j != je; ++j)
954 getReg((TupRegsCopy)[j]);
958 // Now all the registers are known. Build the object graph of explicit
959 // register-register references.
960 for (auto &Reg : Registers)
961 Reg.buildObjectGraph(*this);
963 // Compute register name map.
964 for (auto &Reg : Registers)
965 // FIXME: This could just be RegistersByName[name] = register, except that
966 // causes some failures in MIPS - perhaps they have duplicate register name
967 // entries? (or maybe there's a reason for it - I don't know much about this
968 // code, just drive-by refactoring)
969 RegistersByName.insert(
970 std::make_pair(Reg.TheDef->getValueAsString("AsmName"), &Reg));
972 // Precompute all sub-register maps.
973 // This will create Composite entries for all inferred sub-register indices.
974 for (auto &Reg : Registers)
975 Reg.computeSubRegs(*this);
977 // Infer even more sub-registers by combining leading super-registers.
978 for (auto &Reg : Registers)
979 if (Reg.CoveredBySubRegs)
980 Reg.computeSecondarySubRegs(*this);
982 // After the sub-register graph is complete, compute the topologically
983 // ordered SuperRegs list.
984 for (auto &Reg : Registers)
985 Reg.computeSuperRegs(*this);
987 // Native register units are associated with a leaf register. They've all been
989 NumNativeRegUnits = RegUnits.size();
991 // Read in register class definitions.
992 std::vector<Record*> RCs = Records.getAllDerivedDefinitions("RegisterClass");
994 PrintFatalError("No 'RegisterClass' subclasses defined!");
996 // Allocate user-defined register classes.
997 RegClasses.reserve(RCs.size());
998 for (unsigned i = 0, e = RCs.size(); i != e; ++i)
999 addToMaps(new CodeGenRegisterClass(*this, RCs[i]));
1001 // Infer missing classes to create a full algebra.
1002 computeInferredRegisterClasses();
1004 // Order register classes topologically and assign enum values.
1005 array_pod_sort(RegClasses.begin(), RegClasses.end(), TopoOrderRC);
1006 for (unsigned i = 0, e = RegClasses.size(); i != e; ++i)
1007 RegClasses[i]->EnumValue = i;
1008 CodeGenRegisterClass::computeSubClasses(*this);
1011 CodeGenRegBank::~CodeGenRegBank() {
1012 DeleteContainerPointers(RegClasses);
1015 // Create a synthetic CodeGenSubRegIndex without a corresponding Record.
1017 CodeGenRegBank::createSubRegIndex(StringRef Name, StringRef Namespace) {
1018 SubRegIndices.emplace_back(Name, Namespace, SubRegIndices.size() + 1);
1019 return &SubRegIndices.back();
1022 CodeGenSubRegIndex *CodeGenRegBank::getSubRegIdx(Record *Def) {
1023 CodeGenSubRegIndex *&Idx = Def2SubRegIdx[Def];
1026 SubRegIndices.emplace_back(Def, SubRegIndices.size() + 1);
1027 Idx = &SubRegIndices.back();
1031 CodeGenRegister *CodeGenRegBank::getReg(Record *Def) {
1032 CodeGenRegister *&Reg = Def2Reg[Def];
1035 Registers.emplace_back(Def, Registers.size() + 1);
1036 Reg = &Registers.back();
1040 void CodeGenRegBank::addToMaps(CodeGenRegisterClass *RC) {
1041 RegClasses.push_back(RC);
1043 if (Record *Def = RC->getDef())
1044 Def2RC.insert(std::make_pair(Def, RC));
1046 // Duplicate classes are rejected by insert().
1047 // That's OK, we only care about the properties handled by CGRC::Key.
1048 CodeGenRegisterClass::Key K(*RC);
1049 Key2RC.insert(std::make_pair(K, RC));
1052 // Create a synthetic sub-class if it is missing.
1053 CodeGenRegisterClass*
1054 CodeGenRegBank::getOrCreateSubClass(const CodeGenRegisterClass *RC,
1055 const CodeGenRegister::Set *Members,
1057 // Synthetic sub-class has the same size and alignment as RC.
1058 CodeGenRegisterClass::Key K(Members, RC->SpillSize, RC->SpillAlignment);
1059 RCKeyMap::const_iterator FoundI = Key2RC.find(K);
1060 if (FoundI != Key2RC.end())
1061 return FoundI->second;
1063 // Sub-class doesn't exist, create a new one.
1064 CodeGenRegisterClass *NewRC = new CodeGenRegisterClass(*this, Name, K);
1069 CodeGenRegisterClass *CodeGenRegBank::getRegClass(Record *Def) {
1070 if (CodeGenRegisterClass *RC = Def2RC[Def])
1073 PrintFatalError(Def->getLoc(), "Not a known RegisterClass!");
1077 CodeGenRegBank::getCompositeSubRegIndex(CodeGenSubRegIndex *A,
1078 CodeGenSubRegIndex *B) {
1079 // Look for an existing entry.
1080 CodeGenSubRegIndex *Comp = A->compose(B);
1084 // None exists, synthesize one.
1085 std::string Name = A->getName() + "_then_" + B->getName();
1086 Comp = createSubRegIndex(Name, A->getNamespace());
1087 A->addComposite(B, Comp);
1091 CodeGenSubRegIndex *CodeGenRegBank::
1092 getConcatSubRegIndex(const SmallVector<CodeGenSubRegIndex *, 8> &Parts) {
1093 assert(Parts.size() > 1 && "Need two parts to concatenate");
1095 // Look for an existing entry.
1096 CodeGenSubRegIndex *&Idx = ConcatIdx[Parts];
1100 // None exists, synthesize one.
1101 std::string Name = Parts.front()->getName();
1102 // Determine whether all parts are contiguous.
1103 bool isContinuous = true;
1104 unsigned Size = Parts.front()->Size;
1105 unsigned LastOffset = Parts.front()->Offset;
1106 unsigned LastSize = Parts.front()->Size;
1107 for (unsigned i = 1, e = Parts.size(); i != e; ++i) {
1109 Name += Parts[i]->getName();
1110 Size += Parts[i]->Size;
1111 if (Parts[i]->Offset != (LastOffset + LastSize))
1112 isContinuous = false;
1113 LastOffset = Parts[i]->Offset;
1114 LastSize = Parts[i]->Size;
1116 Idx = createSubRegIndex(Name, Parts.front()->getNamespace());
1118 Idx->Offset = isContinuous ? Parts.front()->Offset : -1;
1122 void CodeGenRegBank::computeComposites() {
1123 // Keep track of TopoSigs visited. We only need to visit each TopoSig once,
1124 // and many registers will share TopoSigs on regular architectures.
1125 BitVector TopoSigs(getNumTopoSigs());
1127 for (const auto &Reg1 : Registers) {
1128 // Skip identical subreg structures already processed.
1129 if (TopoSigs.test(Reg1.getTopoSig()))
1131 TopoSigs.set(Reg1.getTopoSig());
1133 const CodeGenRegister::SubRegMap &SRM1 = Reg1.getSubRegs();
1134 for (CodeGenRegister::SubRegMap::const_iterator i1 = SRM1.begin(),
1135 e1 = SRM1.end(); i1 != e1; ++i1) {
1136 CodeGenSubRegIndex *Idx1 = i1->first;
1137 CodeGenRegister *Reg2 = i1->second;
1138 // Ignore identity compositions.
1141 const CodeGenRegister::SubRegMap &SRM2 = Reg2->getSubRegs();
1142 // Try composing Idx1 with another SubRegIndex.
1143 for (CodeGenRegister::SubRegMap::const_iterator i2 = SRM2.begin(),
1144 e2 = SRM2.end(); i2 != e2; ++i2) {
1145 CodeGenSubRegIndex *Idx2 = i2->first;
1146 CodeGenRegister *Reg3 = i2->second;
1147 // Ignore identity compositions.
1150 // OK Reg1:IdxPair == Reg3. Find the index with Reg:Idx == Reg3.
1151 CodeGenSubRegIndex *Idx3 = Reg1.getSubRegIndex(Reg3);
1152 assert(Idx3 && "Sub-register doesn't have an index");
1154 // Conflicting composition? Emit a warning but allow it.
1155 if (CodeGenSubRegIndex *Prev = Idx1->addComposite(Idx2, Idx3))
1156 PrintWarning(Twine("SubRegIndex ") + Idx1->getQualifiedName() +
1157 " and " + Idx2->getQualifiedName() +
1158 " compose ambiguously as " + Prev->getQualifiedName() +
1159 " or " + Idx3->getQualifiedName());
1165 // Compute lane masks. This is similar to register units, but at the
1166 // sub-register index level. Each bit in the lane mask is like a register unit
1167 // class, and two lane masks will have a bit in common if two sub-register
1168 // indices overlap in some register.
1170 // Conservatively share a lane mask bit if two sub-register indices overlap in
1171 // some registers, but not in others. That shouldn't happen a lot.
1172 void CodeGenRegBank::computeSubRegIndexLaneMasks() {
1173 // First assign individual bits to all the leaf indices.
1175 // Determine mask of lanes that cover their registers.
1176 CoveringLanes = ~0u;
1177 for (auto &Idx : SubRegIndices) {
1178 if (Idx.getComposites().empty()) {
1179 Idx.LaneMask = 1u << Bit;
1180 // Share bit 31 in the unlikely case there are more than 32 leafs.
1182 // Sharing bits is harmless; it allows graceful degradation in targets
1183 // with more than 32 vector lanes. They simply get a limited resolution
1184 // view of lanes beyond the 32nd.
1186 // See also the comment for getSubRegIndexLaneMask().
1190 // Once bit 31 is shared among multiple leafs, the 'lane' it represents
1191 // is no longer covering its registers.
1192 CoveringLanes &= ~(1u << Bit);
1198 // FIXME: What if ad-hoc aliasing introduces overlaps that aren't represented
1199 // by the sub-register graph? This doesn't occur in any known targets.
1201 // Inherit lanes from composites.
1202 for (const auto &Idx : SubRegIndices) {
1203 unsigned Mask = Idx.computeLaneMask();
1204 // If some super-registers without CoveredBySubRegs use this index, we can
1205 // no longer assume that the lanes are covering their registers.
1206 if (!Idx.AllSuperRegsCovered)
1207 CoveringLanes &= ~Mask;
1212 // UberRegSet is a helper class for computeRegUnitWeights. Each UberRegSet is
1213 // the transitive closure of the union of overlapping register
1214 // classes. Together, the UberRegSets form a partition of the registers. If we
1215 // consider overlapping register classes to be connected, then each UberRegSet
1216 // is a set of connected components.
1218 // An UberRegSet will likely be a horizontal slice of register names of
1219 // the same width. Nontrivial subregisters should then be in a separate
1220 // UberRegSet. But this property isn't required for valid computation of
1221 // register unit weights.
1223 // A Weight field caches the max per-register unit weight in each UberRegSet.
1225 // A set of SingularDeterminants flags single units of some register in this set
1226 // for which the unit weight equals the set weight. These units should not have
1227 // their weight increased.
1229 CodeGenRegister::Set Regs;
1231 CodeGenRegister::RegUnitList SingularDeterminants;
1233 UberRegSet(): Weight(0) {}
1237 // Partition registers into UberRegSets, where each set is the transitive
1238 // closure of the union of overlapping register classes.
1240 // UberRegSets[0] is a special non-allocatable set.
1241 static void computeUberSets(std::vector<UberRegSet> &UberSets,
1242 std::vector<UberRegSet*> &RegSets,
1243 CodeGenRegBank &RegBank) {
1245 const auto &Registers = RegBank.getRegisters();
1247 // The Register EnumValue is one greater than its index into Registers.
1248 assert(Registers.size() == Registers.back().EnumValue &&
1249 "register enum value mismatch");
1251 // For simplicitly make the SetID the same as EnumValue.
1252 IntEqClasses UberSetIDs(Registers.size()+1);
1253 std::set<unsigned> AllocatableRegs;
1254 for (unsigned i = 0, e = RegBank.getRegClasses().size(); i != e; ++i) {
1256 CodeGenRegisterClass *RegClass = RegBank.getRegClasses()[i];
1257 if (!RegClass->Allocatable)
1260 const CodeGenRegister::Set &Regs = RegClass->getMembers();
1264 unsigned USetID = UberSetIDs.findLeader((*Regs.begin())->EnumValue);
1265 assert(USetID && "register number 0 is invalid");
1267 AllocatableRegs.insert((*Regs.begin())->EnumValue);
1268 for (CodeGenRegister::Set::const_iterator I = std::next(Regs.begin()),
1269 E = Regs.end(); I != E; ++I) {
1270 AllocatableRegs.insert((*I)->EnumValue);
1271 UberSetIDs.join(USetID, (*I)->EnumValue);
1274 // Combine non-allocatable regs.
1275 for (const auto &Reg : Registers) {
1276 unsigned RegNum = Reg.EnumValue;
1277 if (AllocatableRegs.count(RegNum))
1280 UberSetIDs.join(0, RegNum);
1282 UberSetIDs.compress();
1284 // Make the first UberSet a special unallocatable set.
1285 unsigned ZeroID = UberSetIDs[0];
1287 // Insert Registers into the UberSets formed by union-find.
1288 // Do not resize after this.
1289 UberSets.resize(UberSetIDs.getNumClasses());
1291 for (const CodeGenRegister &Reg : Registers) {
1292 unsigned USetID = UberSetIDs[Reg.EnumValue];
1295 else if (USetID == ZeroID)
1298 UberRegSet *USet = &UberSets[USetID];
1299 USet->Regs.insert(&Reg);
1300 RegSets[i++] = USet;
1304 // Recompute each UberSet weight after changing unit weights.
1305 static void computeUberWeights(std::vector<UberRegSet> &UberSets,
1306 CodeGenRegBank &RegBank) {
1307 // Skip the first unallocatable set.
1308 for (std::vector<UberRegSet>::iterator I = std::next(UberSets.begin()),
1309 E = UberSets.end(); I != E; ++I) {
1311 // Initialize all unit weights in this set, and remember the max units/reg.
1312 const CodeGenRegister *Reg = nullptr;
1313 unsigned MaxWeight = 0, Weight = 0;
1314 for (RegUnitIterator UnitI(I->Regs); UnitI.isValid(); ++UnitI) {
1315 if (Reg != UnitI.getReg()) {
1316 if (Weight > MaxWeight)
1318 Reg = UnitI.getReg();
1321 unsigned UWeight = RegBank.getRegUnit(*UnitI).Weight;
1324 RegBank.increaseRegUnitWeight(*UnitI, UWeight);
1328 if (Weight > MaxWeight)
1330 if (I->Weight != MaxWeight) {
1332 dbgs() << "UberSet " << I - UberSets.begin() << " Weight " << MaxWeight;
1333 for (CodeGenRegister::Set::iterator
1334 UnitI = I->Regs.begin(), UnitE = I->Regs.end();
1335 UnitI != UnitE; ++UnitI) {
1336 dbgs() << " " << (*UnitI)->getName();
1339 // Update the set weight.
1340 I->Weight = MaxWeight;
1343 // Find singular determinants.
1344 for (CodeGenRegister::Set::iterator RegI = I->Regs.begin(),
1345 RegE = I->Regs.end(); RegI != RegE; ++RegI) {
1346 if ((*RegI)->getRegUnits().size() == 1
1347 && (*RegI)->getWeight(RegBank) == I->Weight)
1348 mergeRegUnits(I->SingularDeterminants, (*RegI)->getRegUnits());
1353 // normalizeWeight is a computeRegUnitWeights helper that adjusts the weight of
1354 // a register and its subregisters so that they have the same weight as their
1355 // UberSet. Self-recursion processes the subregister tree in postorder so
1356 // subregisters are normalized first.
1359 // - creates new adopted register units
1360 // - causes superregisters to inherit adopted units
1361 // - increases the weight of "singular" units
1362 // - induces recomputation of UberWeights.
1363 static bool normalizeWeight(CodeGenRegister *Reg,
1364 std::vector<UberRegSet> &UberSets,
1365 std::vector<UberRegSet*> &RegSets,
1366 std::set<unsigned> &NormalRegs,
1367 CodeGenRegister::RegUnitList &NormalUnits,
1368 CodeGenRegBank &RegBank) {
1369 bool Changed = false;
1370 if (!NormalRegs.insert(Reg->EnumValue).second)
1373 const CodeGenRegister::SubRegMap &SRM = Reg->getSubRegs();
1374 for (CodeGenRegister::SubRegMap::const_iterator SRI = SRM.begin(),
1375 SRE = SRM.end(); SRI != SRE; ++SRI) {
1376 if (SRI->second == Reg)
1377 continue; // self-cycles happen
1379 Changed |= normalizeWeight(SRI->second, UberSets, RegSets,
1380 NormalRegs, NormalUnits, RegBank);
1382 // Postorder register normalization.
1384 // Inherit register units newly adopted by subregisters.
1385 if (Reg->inheritRegUnits(RegBank))
1386 computeUberWeights(UberSets, RegBank);
1388 // Check if this register is too skinny for its UberRegSet.
1389 UberRegSet *UberSet = RegSets[RegBank.getRegIndex(Reg)];
1391 unsigned RegWeight = Reg->getWeight(RegBank);
1392 if (UberSet->Weight > RegWeight) {
1393 // A register unit's weight can be adjusted only if it is the singular unit
1394 // for this register, has not been used to normalize a subregister's set,
1395 // and has not already been used to singularly determine this UberRegSet.
1396 unsigned AdjustUnit = Reg->getRegUnits().front();
1397 if (Reg->getRegUnits().size() != 1
1398 || hasRegUnit(NormalUnits, AdjustUnit)
1399 || hasRegUnit(UberSet->SingularDeterminants, AdjustUnit)) {
1400 // We don't have an adjustable unit, so adopt a new one.
1401 AdjustUnit = RegBank.newRegUnit(UberSet->Weight - RegWeight);
1402 Reg->adoptRegUnit(AdjustUnit);
1403 // Adopting a unit does not immediately require recomputing set weights.
1406 // Adjust the existing single unit.
1407 RegBank.increaseRegUnitWeight(AdjustUnit, UberSet->Weight - RegWeight);
1408 // The unit may be shared among sets and registers within this set.
1409 computeUberWeights(UberSets, RegBank);
1414 // Mark these units normalized so superregisters can't change their weights.
1415 mergeRegUnits(NormalUnits, Reg->getRegUnits());
1420 // Compute a weight for each register unit created during getSubRegs.
1422 // The goal is that two registers in the same class will have the same weight,
1423 // where each register's weight is defined as sum of its units' weights.
1424 void CodeGenRegBank::computeRegUnitWeights() {
1425 std::vector<UberRegSet> UberSets;
1426 std::vector<UberRegSet*> RegSets(Registers.size());
1427 computeUberSets(UberSets, RegSets, *this);
1428 // UberSets and RegSets are now immutable.
1430 computeUberWeights(UberSets, *this);
1432 // Iterate over each Register, normalizing the unit weights until reaching
1434 unsigned NumIters = 0;
1435 for (bool Changed = true; Changed; ++NumIters) {
1436 assert(NumIters <= NumNativeRegUnits && "Runaway register unit weights");
1438 for (auto &Reg : Registers) {
1439 CodeGenRegister::RegUnitList NormalUnits;
1440 std::set<unsigned> NormalRegs;
1441 Changed |= normalizeWeight(&Reg, UberSets, RegSets, NormalRegs,
1442 NormalUnits, *this);
1447 // Find a set in UniqueSets with the same elements as Set.
1448 // Return an iterator into UniqueSets.
1449 static std::vector<RegUnitSet>::const_iterator
1450 findRegUnitSet(const std::vector<RegUnitSet> &UniqueSets,
1451 const RegUnitSet &Set) {
1452 std::vector<RegUnitSet>::const_iterator
1453 I = UniqueSets.begin(), E = UniqueSets.end();
1455 if (I->Units == Set.Units)
1461 // Return true if the RUSubSet is a subset of RUSuperSet.
1462 static bool isRegUnitSubSet(const std::vector<unsigned> &RUSubSet,
1463 const std::vector<unsigned> &RUSuperSet) {
1464 return std::includes(RUSuperSet.begin(), RUSuperSet.end(),
1465 RUSubSet.begin(), RUSubSet.end());
1468 /// Iteratively prune unit sets. Prune subsets that are close to the superset,
1469 /// but with one or two registers removed. We occasionally have registers like
1470 /// APSR and PC thrown in with the general registers. We also see many
1471 /// special-purpose register subsets, such as tail-call and Thumb
1472 /// encodings. Generating all possible overlapping sets is combinatorial and
1473 /// overkill for modeling pressure. Ideally we could fix this statically in
1474 /// tablegen by (1) having the target define register classes that only include
1475 /// the allocatable registers and marking other classes as non-allocatable and
1476 /// (2) having a way to mark special purpose classes as "don't-care" classes for
1477 /// the purpose of pressure. However, we make an attempt to handle targets that
1478 /// are not nicely defined by merging nearly identical register unit sets
1479 /// statically. This generates smaller tables. Then, dynamically, we adjust the
1480 /// set limit by filtering the reserved registers.
1482 /// Merge sets only if the units have the same weight. For example, on ARM,
1483 /// Q-tuples with ssub index 0 include all S regs but also include D16+. We
1484 /// should not expand the S set to include D regs.
1485 void CodeGenRegBank::pruneUnitSets() {
1486 assert(RegClassUnitSets.empty() && "this invalidates RegClassUnitSets");
1488 // Form an equivalence class of UnitSets with no significant difference.
1489 std::vector<unsigned> SuperSetIDs;
1490 for (unsigned SubIdx = 0, EndIdx = RegUnitSets.size();
1491 SubIdx != EndIdx; ++SubIdx) {
1492 const RegUnitSet &SubSet = RegUnitSets[SubIdx];
1493 unsigned SuperIdx = 0;
1494 for (; SuperIdx != EndIdx; ++SuperIdx) {
1495 if (SuperIdx == SubIdx)
1498 unsigned UnitWeight = RegUnits[SubSet.Units[0]].Weight;
1499 const RegUnitSet &SuperSet = RegUnitSets[SuperIdx];
1500 if (isRegUnitSubSet(SubSet.Units, SuperSet.Units)
1501 && (SubSet.Units.size() + 3 > SuperSet.Units.size())
1502 && UnitWeight == RegUnits[SuperSet.Units[0]].Weight
1503 && UnitWeight == RegUnits[SuperSet.Units.back()].Weight) {
1504 DEBUG(dbgs() << "UnitSet " << SubIdx << " subsumed by " << SuperIdx
1509 if (SuperIdx == EndIdx)
1510 SuperSetIDs.push_back(SubIdx);
1512 // Populate PrunedUnitSets with each equivalence class's superset.
1513 std::vector<RegUnitSet> PrunedUnitSets(SuperSetIDs.size());
1514 for (unsigned i = 0, e = SuperSetIDs.size(); i != e; ++i) {
1515 unsigned SuperIdx = SuperSetIDs[i];
1516 PrunedUnitSets[i].Name = RegUnitSets[SuperIdx].Name;
1517 PrunedUnitSets[i].Units.swap(RegUnitSets[SuperIdx].Units);
1519 RegUnitSets.swap(PrunedUnitSets);
1522 // Create a RegUnitSet for each RegClass that contains all units in the class
1523 // including adopted units that are necessary to model register pressure. Then
1524 // iteratively compute RegUnitSets such that the union of any two overlapping
1525 // RegUnitSets is repreresented.
1527 // RegisterInfoEmitter will map each RegClass to its RegUnitClass and any
1528 // RegUnitSet that is a superset of that RegUnitClass.
1529 void CodeGenRegBank::computeRegUnitSets() {
1530 assert(RegUnitSets.empty() && "dirty RegUnitSets");
1532 // Compute a unique RegUnitSet for each RegClass.
1533 ArrayRef<CodeGenRegisterClass*> RegClasses = getRegClasses();
1534 unsigned NumRegClasses = RegClasses.size();
1535 for (unsigned RCIdx = 0, RCEnd = NumRegClasses; RCIdx != RCEnd; ++RCIdx) {
1536 if (!RegClasses[RCIdx]->Allocatable)
1539 // Speculatively grow the RegUnitSets to hold the new set.
1540 RegUnitSets.resize(RegUnitSets.size() + 1);
1541 RegUnitSets.back().Name = RegClasses[RCIdx]->getName();
1543 // Compute a sorted list of units in this class.
1544 RegClasses[RCIdx]->buildRegUnitSet(RegUnitSets.back().Units);
1546 // Find an existing RegUnitSet.
1547 std::vector<RegUnitSet>::const_iterator SetI =
1548 findRegUnitSet(RegUnitSets, RegUnitSets.back());
1549 if (SetI != std::prev(RegUnitSets.end()))
1550 RegUnitSets.pop_back();
1553 DEBUG(dbgs() << "\nBefore pruning:\n";
1554 for (unsigned USIdx = 0, USEnd = RegUnitSets.size();
1555 USIdx < USEnd; ++USIdx) {
1556 dbgs() << "UnitSet " << USIdx << " " << RegUnitSets[USIdx].Name
1558 ArrayRef<unsigned> Units = RegUnitSets[USIdx].Units;
1559 for (unsigned i = 0, e = Units.size(); i < e; ++i)
1560 dbgs() << " " << RegUnits[Units[i]].Roots[0]->getName();
1564 // Iteratively prune unit sets.
1567 DEBUG(dbgs() << "\nBefore union:\n";
1568 for (unsigned USIdx = 0, USEnd = RegUnitSets.size();
1569 USIdx < USEnd; ++USIdx) {
1570 dbgs() << "UnitSet " << USIdx << " " << RegUnitSets[USIdx].Name
1572 ArrayRef<unsigned> Units = RegUnitSets[USIdx].Units;
1573 for (unsigned i = 0, e = Units.size(); i < e; ++i)
1574 dbgs() << " " << RegUnits[Units[i]].Roots[0]->getName();
1577 dbgs() << "\nUnion sets:\n");
1579 // Iterate over all unit sets, including new ones added by this loop.
1580 unsigned NumRegUnitSubSets = RegUnitSets.size();
1581 for (unsigned Idx = 0, EndIdx = RegUnitSets.size(); Idx != EndIdx; ++Idx) {
1582 // In theory, this is combinatorial. In practice, it needs to be bounded
1583 // by a small number of sets for regpressure to be efficient.
1584 // If the assert is hit, we need to implement pruning.
1585 assert(Idx < (2*NumRegUnitSubSets) && "runaway unit set inference");
1587 // Compare new sets with all original classes.
1588 for (unsigned SearchIdx = (Idx >= NumRegUnitSubSets) ? 0 : Idx+1;
1589 SearchIdx != EndIdx; ++SearchIdx) {
1590 std::set<unsigned> Intersection;
1591 std::set_intersection(RegUnitSets[Idx].Units.begin(),
1592 RegUnitSets[Idx].Units.end(),
1593 RegUnitSets[SearchIdx].Units.begin(),
1594 RegUnitSets[SearchIdx].Units.end(),
1595 std::inserter(Intersection, Intersection.begin()));
1596 if (Intersection.empty())
1599 // Speculatively grow the RegUnitSets to hold the new set.
1600 RegUnitSets.resize(RegUnitSets.size() + 1);
1601 RegUnitSets.back().Name =
1602 RegUnitSets[Idx].Name + "+" + RegUnitSets[SearchIdx].Name;
1604 std::set_union(RegUnitSets[Idx].Units.begin(),
1605 RegUnitSets[Idx].Units.end(),
1606 RegUnitSets[SearchIdx].Units.begin(),
1607 RegUnitSets[SearchIdx].Units.end(),
1608 std::inserter(RegUnitSets.back().Units,
1609 RegUnitSets.back().Units.begin()));
1611 // Find an existing RegUnitSet, or add the union to the unique sets.
1612 std::vector<RegUnitSet>::const_iterator SetI =
1613 findRegUnitSet(RegUnitSets, RegUnitSets.back());
1614 if (SetI != std::prev(RegUnitSets.end()))
1615 RegUnitSets.pop_back();
1617 DEBUG(dbgs() << "UnitSet " << RegUnitSets.size()-1
1618 << " " << RegUnitSets.back().Name << ":";
1619 ArrayRef<unsigned> Units = RegUnitSets.back().Units;
1620 for (unsigned i = 0, e = Units.size(); i < e; ++i)
1621 dbgs() << " " << RegUnits[Units[i]].Roots[0]->getName();
1627 // Iteratively prune unit sets after inferring supersets.
1630 DEBUG(dbgs() << "\n";
1631 for (unsigned USIdx = 0, USEnd = RegUnitSets.size();
1632 USIdx < USEnd; ++USIdx) {
1633 dbgs() << "UnitSet " << USIdx << " " << RegUnitSets[USIdx].Name
1635 ArrayRef<unsigned> Units = RegUnitSets[USIdx].Units;
1636 for (unsigned i = 0, e = Units.size(); i < e; ++i)
1637 dbgs() << " " << RegUnits[Units[i]].Roots[0]->getName();
1641 // For each register class, list the UnitSets that are supersets.
1642 RegClassUnitSets.resize(NumRegClasses);
1643 for (unsigned RCIdx = 0, RCEnd = NumRegClasses; RCIdx != RCEnd; ++RCIdx) {
1644 if (!RegClasses[RCIdx]->Allocatable)
1647 // Recompute the sorted list of units in this class.
1648 std::vector<unsigned> RCRegUnits;
1649 RegClasses[RCIdx]->buildRegUnitSet(RCRegUnits);
1651 // Don't increase pressure for unallocatable regclasses.
1652 if (RCRegUnits.empty())
1655 DEBUG(dbgs() << "RC " << RegClasses[RCIdx]->getName() << " Units: \n";
1656 for (unsigned i = 0, e = RCRegUnits.size(); i < e; ++i)
1657 dbgs() << RegUnits[RCRegUnits[i]].getRoots()[0]->getName() << " ";
1658 dbgs() << "\n UnitSetIDs:");
1660 // Find all supersets.
1661 for (unsigned USIdx = 0, USEnd = RegUnitSets.size();
1662 USIdx != USEnd; ++USIdx) {
1663 if (isRegUnitSubSet(RCRegUnits, RegUnitSets[USIdx].Units)) {
1664 DEBUG(dbgs() << " " << USIdx);
1665 RegClassUnitSets[RCIdx].push_back(USIdx);
1668 DEBUG(dbgs() << "\n");
1669 assert(!RegClassUnitSets[RCIdx].empty() && "missing unit set for regclass");
1672 // For each register unit, ensure that we have the list of UnitSets that
1673 // contain the unit. Normally, this matches an existing list of UnitSets for a
1674 // register class. If not, we create a new entry in RegClassUnitSets as a
1675 // "fake" register class.
1676 for (unsigned UnitIdx = 0, UnitEnd = NumNativeRegUnits;
1677 UnitIdx < UnitEnd; ++UnitIdx) {
1678 std::vector<unsigned> RUSets;
1679 for (unsigned i = 0, e = RegUnitSets.size(); i != e; ++i) {
1680 RegUnitSet &RUSet = RegUnitSets[i];
1681 if (std::find(RUSet.Units.begin(), RUSet.Units.end(), UnitIdx)
1682 == RUSet.Units.end())
1684 RUSets.push_back(i);
1686 unsigned RCUnitSetsIdx = 0;
1687 for (unsigned e = RegClassUnitSets.size();
1688 RCUnitSetsIdx != e; ++RCUnitSetsIdx) {
1689 if (RegClassUnitSets[RCUnitSetsIdx] == RUSets) {
1693 RegUnits[UnitIdx].RegClassUnitSetsIdx = RCUnitSetsIdx;
1694 if (RCUnitSetsIdx == RegClassUnitSets.size()) {
1695 // Create a new list of UnitSets as a "fake" register class.
1696 RegClassUnitSets.resize(RCUnitSetsIdx + 1);
1697 RegClassUnitSets[RCUnitSetsIdx].swap(RUSets);
1702 void CodeGenRegBank::computeDerivedInfo() {
1703 computeComposites();
1704 computeSubRegIndexLaneMasks();
1706 // Compute a weight for each register unit created during getSubRegs.
1707 // This may create adopted register units (with unit # >= NumNativeRegUnits).
1708 computeRegUnitWeights();
1710 // Compute a unique set of RegUnitSets. One for each RegClass and inferred
1711 // supersets for the union of overlapping sets.
1712 computeRegUnitSets();
1714 // Get the weight of each set.
1715 for (unsigned Idx = 0, EndIdx = RegUnitSets.size(); Idx != EndIdx; ++Idx)
1716 RegUnitSets[Idx].Weight = getRegUnitSetWeight(RegUnitSets[Idx].Units);
1718 // Find the order of each set.
1719 RegUnitSetOrder.reserve(RegUnitSets.size());
1720 for (unsigned Idx = 0, EndIdx = RegUnitSets.size(); Idx != EndIdx; ++Idx)
1721 RegUnitSetOrder.push_back(Idx);
1723 std::stable_sort(RegUnitSetOrder.begin(), RegUnitSetOrder.end(),
1724 [this](unsigned ID1, unsigned ID2) {
1725 return getRegPressureSet(ID1).Units.size() <
1726 getRegPressureSet(ID2).Units.size();
1728 for (unsigned Idx = 0, EndIdx = RegUnitSets.size(); Idx != EndIdx; ++Idx) {
1729 RegUnitSets[RegUnitSetOrder[Idx]].Order = Idx;
1734 // Synthesize missing register class intersections.
1736 // Make sure that sub-classes of RC exists such that getCommonSubClass(RC, X)
1737 // returns a maximal register class for all X.
1739 void CodeGenRegBank::inferCommonSubClass(CodeGenRegisterClass *RC) {
1740 for (unsigned rci = 0, rce = RegClasses.size(); rci != rce; ++rci) {
1741 CodeGenRegisterClass *RC1 = RC;
1742 CodeGenRegisterClass *RC2 = RegClasses[rci];
1746 // Compute the set intersection of RC1 and RC2.
1747 const CodeGenRegister::Set &Memb1 = RC1->getMembers();
1748 const CodeGenRegister::Set &Memb2 = RC2->getMembers();
1749 CodeGenRegister::Set Intersection;
1750 std::set_intersection(Memb1.begin(), Memb1.end(),
1751 Memb2.begin(), Memb2.end(),
1752 std::inserter(Intersection, Intersection.begin()),
1753 CodeGenRegister::Less());
1755 // Skip disjoint class pairs.
1756 if (Intersection.empty())
1759 // If RC1 and RC2 have different spill sizes or alignments, use the
1760 // larger size for sub-classing. If they are equal, prefer RC1.
1761 if (RC2->SpillSize > RC1->SpillSize ||
1762 (RC2->SpillSize == RC1->SpillSize &&
1763 RC2->SpillAlignment > RC1->SpillAlignment))
1764 std::swap(RC1, RC2);
1766 getOrCreateSubClass(RC1, &Intersection,
1767 RC1->getName() + "_and_" + RC2->getName());
1772 // Synthesize missing sub-classes for getSubClassWithSubReg().
1774 // Make sure that the set of registers in RC with a given SubIdx sub-register
1775 // form a register class. Update RC->SubClassWithSubReg.
1777 void CodeGenRegBank::inferSubClassWithSubReg(CodeGenRegisterClass *RC) {
1778 // Map SubRegIndex to set of registers in RC supporting that SubRegIndex.
1779 typedef std::map<const CodeGenSubRegIndex *, CodeGenRegister::Set,
1780 CodeGenSubRegIndex::Less> SubReg2SetMap;
1782 // Compute the set of registers supporting each SubRegIndex.
1783 SubReg2SetMap SRSets;
1784 for (CodeGenRegister::Set::const_iterator RI = RC->getMembers().begin(),
1785 RE = RC->getMembers().end(); RI != RE; ++RI) {
1786 const CodeGenRegister::SubRegMap &SRM = (*RI)->getSubRegs();
1787 for (CodeGenRegister::SubRegMap::const_iterator I = SRM.begin(),
1788 E = SRM.end(); I != E; ++I)
1789 SRSets[I->first].insert(*RI);
1792 // Find matching classes for all SRSets entries. Iterate in SubRegIndex
1793 // numerical order to visit synthetic indices last.
1794 for (const auto &SubIdx : SubRegIndices) {
1795 SubReg2SetMap::const_iterator I = SRSets.find(&SubIdx);
1796 // Unsupported SubRegIndex. Skip it.
1797 if (I == SRSets.end())
1799 // In most cases, all RC registers support the SubRegIndex.
1800 if (I->second.size() == RC->getMembers().size()) {
1801 RC->setSubClassWithSubReg(&SubIdx, RC);
1804 // This is a real subset. See if we have a matching class.
1805 CodeGenRegisterClass *SubRC =
1806 getOrCreateSubClass(RC, &I->second,
1807 RC->getName() + "_with_" + I->first->getName());
1808 RC->setSubClassWithSubReg(&SubIdx, SubRC);
1813 // Synthesize missing sub-classes of RC for getMatchingSuperRegClass().
1815 // Create sub-classes of RC such that getMatchingSuperRegClass(RC, SubIdx, X)
1816 // has a maximal result for any SubIdx and any X >= FirstSubRegRC.
1819 void CodeGenRegBank::inferMatchingSuperRegClass(CodeGenRegisterClass *RC,
1820 unsigned FirstSubRegRC) {
1821 SmallVector<std::pair<const CodeGenRegister*,
1822 const CodeGenRegister*>, 16> SSPairs;
1823 BitVector TopoSigs(getNumTopoSigs());
1825 // Iterate in SubRegIndex numerical order to visit synthetic indices last.
1826 for (auto &SubIdx : SubRegIndices) {
1827 // Skip indexes that aren't fully supported by RC's registers. This was
1828 // computed by inferSubClassWithSubReg() above which should have been
1830 if (RC->getSubClassWithSubReg(&SubIdx) != RC)
1833 // Build list of (Super, Sub) pairs for this SubIdx.
1836 for (CodeGenRegister::Set::const_iterator RI = RC->getMembers().begin(),
1837 RE = RC->getMembers().end(); RI != RE; ++RI) {
1838 const CodeGenRegister *Super = *RI;
1839 const CodeGenRegister *Sub = Super->getSubRegs().find(&SubIdx)->second;
1840 assert(Sub && "Missing sub-register");
1841 SSPairs.push_back(std::make_pair(Super, Sub));
1842 TopoSigs.set(Sub->getTopoSig());
1845 // Iterate over sub-register class candidates. Ignore classes created by
1846 // this loop. They will never be useful.
1847 for (unsigned rci = FirstSubRegRC, rce = RegClasses.size(); rci != rce;
1849 CodeGenRegisterClass *SubRC = RegClasses[rci];
1850 // Topological shortcut: SubRC members have the wrong shape.
1851 if (!TopoSigs.anyCommon(SubRC->getTopoSigs()))
1853 // Compute the subset of RC that maps into SubRC.
1854 CodeGenRegister::Set SubSet;
1855 for (unsigned i = 0, e = SSPairs.size(); i != e; ++i)
1856 if (SubRC->contains(SSPairs[i].second))
1857 SubSet.insert(SSPairs[i].first);
1860 // RC injects completely into SubRC.
1861 if (SubSet.size() == SSPairs.size()) {
1862 SubRC->addSuperRegClass(&SubIdx, RC);
1865 // Only a subset of RC maps into SubRC. Make sure it is represented by a
1867 getOrCreateSubClass(RC, &SubSet, RC->getName() + "_with_" +
1868 SubIdx.getName() + "_in_" +
1876 // Infer missing register classes.
1878 void CodeGenRegBank::computeInferredRegisterClasses() {
1879 // When this function is called, the register classes have not been sorted
1880 // and assigned EnumValues yet. That means getSubClasses(),
1881 // getSuperClasses(), and hasSubClass() functions are defunct.
1882 unsigned FirstNewRC = RegClasses.size();
1884 // Visit all register classes, including the ones being added by the loop.
1885 for (unsigned rci = 0; rci != RegClasses.size(); ++rci) {
1886 CodeGenRegisterClass *RC = RegClasses[rci];
1888 // Synthesize answers for getSubClassWithSubReg().
1889 inferSubClassWithSubReg(RC);
1891 // Synthesize answers for getCommonSubClass().
1892 inferCommonSubClass(RC);
1894 // Synthesize answers for getMatchingSuperRegClass().
1895 inferMatchingSuperRegClass(RC);
1897 // New register classes are created while this loop is running, and we need
1898 // to visit all of them. I particular, inferMatchingSuperRegClass needs
1899 // to match old super-register classes with sub-register classes created
1900 // after inferMatchingSuperRegClass was called. At this point,
1901 // inferMatchingSuperRegClass has checked SuperRC = [0..rci] with SubRC =
1902 // [0..FirstNewRC). We need to cover SubRC = [FirstNewRC..rci].
1903 if (rci + 1 == FirstNewRC) {
1904 unsigned NextNewRC = RegClasses.size();
1905 for (unsigned rci2 = 0; rci2 != FirstNewRC; ++rci2)
1906 inferMatchingSuperRegClass(RegClasses[rci2], FirstNewRC);
1907 FirstNewRC = NextNewRC;
1912 /// getRegisterClassForRegister - Find the register class that contains the
1913 /// specified physical register. If the register is not in a register class,
1914 /// return null. If the register is in multiple classes, and the classes have a
1915 /// superset-subset relationship and the same set of types, return the
1916 /// superclass. Otherwise return null.
1917 const CodeGenRegisterClass*
1918 CodeGenRegBank::getRegClassForRegister(Record *R) {
1919 const CodeGenRegister *Reg = getReg(R);
1920 ArrayRef<CodeGenRegisterClass*> RCs = getRegClasses();
1921 const CodeGenRegisterClass *FoundRC = nullptr;
1922 for (unsigned i = 0, e = RCs.size(); i != e; ++i) {
1923 const CodeGenRegisterClass &RC = *RCs[i];
1924 if (!RC.contains(Reg))
1927 // If this is the first class that contains the register,
1928 // make a note of it and go on to the next class.
1934 // If a register's classes have different types, return null.
1935 if (RC.getValueTypes() != FoundRC->getValueTypes())
1938 // Check to see if the previously found class that contains
1939 // the register is a subclass of the current class. If so,
1940 // prefer the superclass.
1941 if (RC.hasSubClass(FoundRC)) {
1946 // Check to see if the previously found class that contains
1947 // the register is a superclass of the current class. If so,
1948 // prefer the superclass.
1949 if (FoundRC->hasSubClass(&RC))
1952 // Multiple classes, and neither is a superclass of the other.
1959 BitVector CodeGenRegBank::computeCoveredRegisters(ArrayRef<Record*> Regs) {
1960 SetVector<const CodeGenRegister*> Set;
1962 // First add Regs with all sub-registers.
1963 for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
1964 CodeGenRegister *Reg = getReg(Regs[i]);
1965 if (Set.insert(Reg))
1966 // Reg is new, add all sub-registers.
1967 // The pre-ordering is not important here.
1968 Reg->addSubRegsPreOrder(Set, *this);
1971 // Second, find all super-registers that are completely covered by the set.
1972 for (unsigned i = 0; i != Set.size(); ++i) {
1973 const CodeGenRegister::SuperRegList &SR = Set[i]->getSuperRegs();
1974 for (unsigned j = 0, e = SR.size(); j != e; ++j) {
1975 const CodeGenRegister *Super = SR[j];
1976 if (!Super->CoveredBySubRegs || Set.count(Super))
1978 // This new super-register is covered by its sub-registers.
1979 bool AllSubsInSet = true;
1980 const CodeGenRegister::SubRegMap &SRM = Super->getSubRegs();
1981 for (CodeGenRegister::SubRegMap::const_iterator I = SRM.begin(),
1982 E = SRM.end(); I != E; ++I)
1983 if (!Set.count(I->second)) {
1984 AllSubsInSet = false;
1987 // All sub-registers in Set, add Super as well.
1988 // We will visit Super later to recheck its super-registers.
1994 // Convert to BitVector.
1995 BitVector BV(Registers.size() + 1);
1996 for (unsigned i = 0, e = Set.size(); i != e; ++i)
1997 BV.set(Set[i]->EnumValue);