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/TableGen/Error.h"
18 #include "llvm/ADT/IntEqClasses.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ADT/StringExtras.h"
22 #include "llvm/ADT/Twine.h"
26 //===----------------------------------------------------------------------===//
28 //===----------------------------------------------------------------------===//
30 CodeGenSubRegIndex::CodeGenSubRegIndex(Record *R, unsigned Enum)
35 std::string CodeGenSubRegIndex::getNamespace() const {
36 if (TheDef->getValue("Namespace"))
37 return TheDef->getValueAsString("Namespace");
42 const std::string &CodeGenSubRegIndex::getName() const {
43 return TheDef->getName();
46 std::string CodeGenSubRegIndex::getQualifiedName() const {
47 std::string N = getNamespace();
54 void CodeGenSubRegIndex::updateComponents(CodeGenRegBank &RegBank) {
55 std::vector<Record*> Comps = TheDef->getValueAsListOfDefs("ComposedOf");
58 if (Comps.size() != 2)
59 throw TGError(TheDef->getLoc(), "ComposedOf must have exactly two entries");
60 CodeGenSubRegIndex *A = RegBank.getSubRegIdx(Comps[0]);
61 CodeGenSubRegIndex *B = RegBank.getSubRegIdx(Comps[1]);
62 CodeGenSubRegIndex *X = A->addComposite(B, this);
64 throw TGError(TheDef->getLoc(), "Ambiguous ComposedOf entries");
67 void CodeGenSubRegIndex::cleanComposites() {
68 // Clean out redundant mappings of the form this+X -> X.
69 for (CompMap::iterator i = Composed.begin(), e = Composed.end(); i != e;) {
70 CompMap::iterator j = i;
72 if (j->first == j->second)
77 //===----------------------------------------------------------------------===//
79 //===----------------------------------------------------------------------===//
81 CodeGenRegister::CodeGenRegister(Record *R, unsigned Enum)
84 CostPerUse(R->getValueAsInt("CostPerUse")),
85 CoveredBySubRegs(R->getValueAsBit("CoveredBySubRegs")),
86 SubRegsComplete(false)
89 const std::string &CodeGenRegister::getName() const {
90 return TheDef->getName();
94 // Iterate over all register units in a set of registers.
95 class RegUnitIterator {
96 CodeGenRegister::Set::const_iterator RegI, RegE;
97 CodeGenRegister::RegUnitList::const_iterator UnitI, UnitE;
100 RegUnitIterator(const CodeGenRegister::Set &Regs):
101 RegI(Regs.begin()), RegE(Regs.end()), UnitI(), UnitE() {
104 UnitI = (*RegI)->getRegUnits().begin();
105 UnitE = (*RegI)->getRegUnits().end();
110 bool isValid() const { return UnitI != UnitE; }
112 unsigned operator* () const { assert(isValid()); return *UnitI; };
114 const CodeGenRegister *getReg() const { assert(isValid()); return *RegI; }
116 /// Preincrement. Move to the next unit.
118 assert(isValid() && "Cannot advance beyond the last operand");
125 while (UnitI == UnitE) {
128 UnitI = (*RegI)->getRegUnits().begin();
129 UnitE = (*RegI)->getRegUnits().end();
135 // Merge two RegUnitLists maintaining the order and removing duplicates.
136 // Overwrites MergedRU in the process.
137 static void mergeRegUnits(CodeGenRegister::RegUnitList &MergedRU,
138 const CodeGenRegister::RegUnitList &RRU) {
139 CodeGenRegister::RegUnitList LRU = MergedRU;
141 std::set_union(LRU.begin(), LRU.end(), RRU.begin(), RRU.end(),
142 std::back_inserter(MergedRU));
145 // Return true of this unit appears in RegUnits.
146 static bool hasRegUnit(CodeGenRegister::RegUnitList &RegUnits, unsigned Unit) {
147 return std::count(RegUnits.begin(), RegUnits.end(), Unit);
150 // Inherit register units from subregisters.
151 // Return true if the RegUnits changed.
152 bool CodeGenRegister::inheritRegUnits(CodeGenRegBank &RegBank) {
153 unsigned OldNumUnits = RegUnits.size();
154 for (SubRegMap::const_iterator I = SubRegs.begin(), E = SubRegs.end();
156 // Strangely a register may have itself as a subreg (self-cycle) e.g. XMM.
157 // Only create a unit if no other subregs have units.
158 CodeGenRegister *SR = I->second;
160 // RegUnits are only empty during getSubRegs, prior to computing weight.
161 if (RegUnits.empty())
162 RegUnits.push_back(RegBank.newRegUnit(0));
165 // Merge the subregister's units into this register's RegUnits.
166 mergeRegUnits(RegUnits, SR->RegUnits);
168 return OldNumUnits != RegUnits.size();
171 const CodeGenRegister::SubRegMap &
172 CodeGenRegister::getSubRegs(CodeGenRegBank &RegBank) {
173 // Only compute this map once.
176 SubRegsComplete = true;
178 std::vector<Record*> SubList = TheDef->getValueAsListOfDefs("SubRegs");
179 std::vector<Record*> IdxList = TheDef->getValueAsListOfDefs("SubRegIndices");
180 if (SubList.size() != IdxList.size())
181 throw TGError(TheDef->getLoc(), "Register " + getName() +
182 " SubRegIndices doesn't match SubRegs");
184 // First insert the direct subregs and make sure they are fully indexed.
185 SmallVector<CodeGenSubRegIndex*, 8> Indices;
186 for (unsigned i = 0, e = SubList.size(); i != e; ++i) {
187 CodeGenRegister *SR = RegBank.getReg(SubList[i]);
188 CodeGenSubRegIndex *Idx = RegBank.getSubRegIdx(IdxList[i]);
189 Indices.push_back(Idx);
190 if (!SubRegs.insert(std::make_pair(Idx, SR)).second)
191 throw TGError(TheDef->getLoc(), "SubRegIndex " + Idx->getName() +
192 " appears twice in Register " + getName());
195 // Keep track of inherited subregs and how they can be reached.
196 SmallPtrSet<CodeGenRegister*, 8> Orphans;
198 // Clone inherited subregs and place duplicate entries in Orphans.
199 // Here the order is important - earlier subregs take precedence.
200 for (unsigned i = 0, e = SubList.size(); i != e; ++i) {
201 CodeGenRegister *SR = RegBank.getReg(SubList[i]);
202 const SubRegMap &Map = SR->getSubRegs(RegBank);
204 // Add this as a super-register of SR now all sub-registers are in the list.
205 // This creates a topological ordering, the exact order depends on the
206 // order getSubRegs is called on all registers.
207 SR->SuperRegs.push_back(this);
209 for (SubRegMap::const_iterator SI = Map.begin(), SE = Map.end(); SI != SE;
211 if (!SubRegs.insert(*SI).second)
212 Orphans.insert(SI->second);
214 // Noop sub-register indexes are possible, so avoid duplicates.
215 if (SI->second != SR)
216 SI->second->SuperRegs.push_back(this);
220 // Expand any composed subreg indices.
221 // If dsub_2 has ComposedOf = [qsub_1, dsub_0], and this register has a
222 // qsub_1 subreg, add a dsub_2 subreg. Keep growing Indices and process
223 // expanded subreg indices recursively.
224 for (unsigned i = 0; i != Indices.size(); ++i) {
225 CodeGenSubRegIndex *Idx = Indices[i];
226 const CodeGenSubRegIndex::CompMap &Comps = Idx->getComposites();
227 CodeGenRegister *SR = SubRegs[Idx];
228 const SubRegMap &Map = SR->getSubRegs(RegBank);
230 // Look at the possible compositions of Idx.
231 // They may not all be supported by SR.
232 for (CodeGenSubRegIndex::CompMap::const_iterator I = Comps.begin(),
233 E = Comps.end(); I != E; ++I) {
234 SubRegMap::const_iterator SRI = Map.find(I->first);
235 if (SRI == Map.end())
236 continue; // Idx + I->first doesn't exist in SR.
237 // Add I->second as a name for the subreg SRI->second, assuming it is
238 // orphaned, and the name isn't already used for something else.
239 if (SubRegs.count(I->second) || !Orphans.erase(SRI->second))
241 // We found a new name for the orphaned sub-register.
242 SubRegs.insert(std::make_pair(I->second, SRI->second));
243 Indices.push_back(I->second);
247 // Process the composites.
248 ListInit *Comps = TheDef->getValueAsListInit("CompositeIndices");
249 for (unsigned i = 0, e = Comps->size(); i != e; ++i) {
250 DagInit *Pat = dynamic_cast<DagInit*>(Comps->getElement(i));
252 throw TGError(TheDef->getLoc(), "Invalid dag '" +
253 Comps->getElement(i)->getAsString() +
254 "' in CompositeIndices");
255 DefInit *BaseIdxInit = dynamic_cast<DefInit*>(Pat->getOperator());
256 if (!BaseIdxInit || !BaseIdxInit->getDef()->isSubClassOf("SubRegIndex"))
257 throw TGError(TheDef->getLoc(), "Invalid SubClassIndex in " +
259 CodeGenSubRegIndex *BaseIdx = RegBank.getSubRegIdx(BaseIdxInit->getDef());
261 // Resolve list of subreg indices into R2.
262 CodeGenRegister *R2 = this;
263 for (DagInit::const_arg_iterator di = Pat->arg_begin(),
264 de = Pat->arg_end(); di != de; ++di) {
265 DefInit *IdxInit = dynamic_cast<DefInit*>(*di);
266 if (!IdxInit || !IdxInit->getDef()->isSubClassOf("SubRegIndex"))
267 throw TGError(TheDef->getLoc(), "Invalid SubClassIndex in " +
269 CodeGenSubRegIndex *Idx = RegBank.getSubRegIdx(IdxInit->getDef());
270 const SubRegMap &R2Subs = R2->getSubRegs(RegBank);
271 SubRegMap::const_iterator ni = R2Subs.find(Idx);
272 if (ni == R2Subs.end())
273 throw TGError(TheDef->getLoc(), "Composite " + Pat->getAsString() +
274 " refers to bad index in " + R2->getName());
278 // Insert composite index. Allow overriding inherited indices etc.
279 SubRegs[BaseIdx] = R2;
281 // R2 is no longer an orphan.
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 neccessarily 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->getSubRegs(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 // Initialize RegUnitList. A register with no subregisters creates its own
312 // unit. Otherwise, it inherits all its subregister's units. Because
313 // getSubRegs is called recursively, this processes the register hierarchy in
316 // TODO: We currently assume all register units correspond to a named "leaf"
317 // register. We should also unify register units for ad-hoc register
318 // aliases. This can be done by iteratively merging units for aliasing
319 // registers using a worklist.
320 assert(RegUnits.empty() && "Should only initialize RegUnits once");
322 RegUnits.push_back(RegBank.newRegUnit(0));
324 inheritRegUnits(RegBank);
329 CodeGenRegister::addSubRegsPreOrder(SetVector<const CodeGenRegister*> &OSet,
330 CodeGenRegBank &RegBank) const {
331 assert(SubRegsComplete && "Must precompute sub-registers");
332 std::vector<Record*> Indices = TheDef->getValueAsListOfDefs("SubRegIndices");
333 for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
334 CodeGenSubRegIndex *Idx = RegBank.getSubRegIdx(Indices[i]);
335 CodeGenRegister *SR = SubRegs.find(Idx)->second;
337 SR->addSubRegsPreOrder(OSet, RegBank);
341 // Get the sum of this register's unit weights.
342 unsigned CodeGenRegister::getWeight(const CodeGenRegBank &RegBank) const {
344 for (RegUnitList::const_iterator I = RegUnits.begin(), E = RegUnits.end();
346 Weight += RegBank.getRegUnitWeight(*I);
351 //===----------------------------------------------------------------------===//
353 //===----------------------------------------------------------------------===//
355 // A RegisterTuples def is used to generate pseudo-registers from lists of
356 // sub-registers. We provide a SetTheory expander class that returns the new
359 struct TupleExpander : SetTheory::Expander {
360 void expand(SetTheory &ST, Record *Def, SetTheory::RecSet &Elts) {
361 std::vector<Record*> Indices = Def->getValueAsListOfDefs("SubRegIndices");
362 unsigned Dim = Indices.size();
363 ListInit *SubRegs = Def->getValueAsListInit("SubRegs");
364 if (Dim != SubRegs->getSize())
365 throw TGError(Def->getLoc(), "SubRegIndices and SubRegs size mismatch");
367 throw TGError(Def->getLoc(), "Tuples must have at least 2 sub-registers");
369 // Evaluate the sub-register lists to be zipped.
370 unsigned Length = ~0u;
371 SmallVector<SetTheory::RecSet, 4> Lists(Dim);
372 for (unsigned i = 0; i != Dim; ++i) {
373 ST.evaluate(SubRegs->getElement(i), Lists[i]);
374 Length = std::min(Length, unsigned(Lists[i].size()));
380 // Precompute some types.
381 Record *RegisterCl = Def->getRecords().getClass("Register");
382 RecTy *RegisterRecTy = RecordRecTy::get(RegisterCl);
383 StringInit *BlankName = StringInit::get("");
386 for (unsigned n = 0; n != Length; ++n) {
388 Record *Proto = Lists[0][n];
389 std::vector<Init*> Tuple;
390 unsigned CostPerUse = 0;
391 for (unsigned i = 0; i != Dim; ++i) {
392 Record *Reg = Lists[i][n];
394 Name += Reg->getName();
395 Tuple.push_back(DefInit::get(Reg));
396 CostPerUse = std::max(CostPerUse,
397 unsigned(Reg->getValueAsInt("CostPerUse")));
400 // Create a new Record representing the synthesized register. This record
401 // is only for consumption by CodeGenRegister, it is not added to the
403 Record *NewReg = new Record(Name, Def->getLoc(), Def->getRecords());
406 // Copy Proto super-classes.
407 for (unsigned i = 0, e = Proto->getSuperClasses().size(); i != e; ++i)
408 NewReg->addSuperClass(Proto->getSuperClasses()[i]);
410 // Copy Proto fields.
411 for (unsigned i = 0, e = Proto->getValues().size(); i != e; ++i) {
412 RecordVal RV = Proto->getValues()[i];
414 // Skip existing fields, like NAME.
415 if (NewReg->getValue(RV.getNameInit()))
418 StringRef Field = RV.getName();
420 // Replace the sub-register list with Tuple.
421 if (Field == "SubRegs")
422 RV.setValue(ListInit::get(Tuple, RegisterRecTy));
424 // Provide a blank AsmName. MC hacks are required anyway.
425 if (Field == "AsmName")
426 RV.setValue(BlankName);
428 // CostPerUse is aggregated from all Tuple members.
429 if (Field == "CostPerUse")
430 RV.setValue(IntInit::get(CostPerUse));
432 // Composite registers are always covered by sub-registers.
433 if (Field == "CoveredBySubRegs")
434 RV.setValue(BitInit::get(true));
436 // Copy fields from the RegisterTuples def.
437 if (Field == "SubRegIndices" ||
438 Field == "CompositeIndices") {
439 NewReg->addValue(*Def->getValue(Field));
443 // Some fields get their default uninitialized value.
444 if (Field == "DwarfNumbers" ||
445 Field == "DwarfAlias" ||
446 Field == "Aliases") {
447 if (const RecordVal *DefRV = RegisterCl->getValue(Field))
448 NewReg->addValue(*DefRV);
452 // Everything else is copied from Proto.
453 NewReg->addValue(RV);
460 //===----------------------------------------------------------------------===//
461 // CodeGenRegisterClass
462 //===----------------------------------------------------------------------===//
464 CodeGenRegisterClass::CodeGenRegisterClass(CodeGenRegBank &RegBank, Record *R)
465 : TheDef(R), Name(R->getName()), EnumValue(-1) {
466 // Rename anonymous register classes.
467 if (R->getName().size() > 9 && R->getName()[9] == '.') {
468 static unsigned AnonCounter = 0;
469 R->setName("AnonRegClass_"+utostr(AnonCounter++));
472 std::vector<Record*> TypeList = R->getValueAsListOfDefs("RegTypes");
473 for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
474 Record *Type = TypeList[i];
475 if (!Type->isSubClassOf("ValueType"))
476 throw "RegTypes list member '" + Type->getName() +
477 "' does not derive from the ValueType class!";
478 VTs.push_back(getValueType(Type));
480 assert(!VTs.empty() && "RegisterClass must contain at least one ValueType!");
482 // Allocation order 0 is the full set. AltOrders provides others.
483 const SetTheory::RecVec *Elements = RegBank.getSets().expand(R);
484 ListInit *AltOrders = R->getValueAsListInit("AltOrders");
485 Orders.resize(1 + AltOrders->size());
487 // Default allocation order always contains all registers.
488 for (unsigned i = 0, e = Elements->size(); i != e; ++i) {
489 Orders[0].push_back((*Elements)[i]);
490 Members.insert(RegBank.getReg((*Elements)[i]));
493 // Alternative allocation orders may be subsets.
494 SetTheory::RecSet Order;
495 for (unsigned i = 0, e = AltOrders->size(); i != e; ++i) {
496 RegBank.getSets().evaluate(AltOrders->getElement(i), Order);
497 Orders[1 + i].append(Order.begin(), Order.end());
498 // Verify that all altorder members are regclass members.
499 while (!Order.empty()) {
500 CodeGenRegister *Reg = RegBank.getReg(Order.back());
503 throw TGError(R->getLoc(), " AltOrder register " + Reg->getName() +
504 " is not a class member");
508 // Allow targets to override the size in bits of the RegisterClass.
509 unsigned Size = R->getValueAsInt("Size");
511 Namespace = R->getValueAsString("Namespace");
512 SpillSize = Size ? Size : EVT(VTs[0]).getSizeInBits();
513 SpillAlignment = R->getValueAsInt("Alignment");
514 CopyCost = R->getValueAsInt("CopyCost");
515 Allocatable = R->getValueAsBit("isAllocatable");
516 AltOrderSelect = R->getValueAsString("AltOrderSelect");
519 // Create an inferred register class that was missing from the .td files.
520 // Most properties will be inherited from the closest super-class after the
521 // class structure has been computed.
522 CodeGenRegisterClass::CodeGenRegisterClass(StringRef Name, Key Props)
523 : Members(*Props.Members),
527 SpillSize(Props.SpillSize),
528 SpillAlignment(Props.SpillAlignment),
533 // Compute inherited propertied for a synthesized register class.
534 void CodeGenRegisterClass::inheritProperties(CodeGenRegBank &RegBank) {
535 assert(!getDef() && "Only synthesized classes can inherit properties");
536 assert(!SuperClasses.empty() && "Synthesized class without super class");
538 // The last super-class is the smallest one.
539 CodeGenRegisterClass &Super = *SuperClasses.back();
541 // Most properties are copied directly.
542 // Exceptions are members, size, and alignment
543 Namespace = Super.Namespace;
545 CopyCost = Super.CopyCost;
546 Allocatable = Super.Allocatable;
547 AltOrderSelect = Super.AltOrderSelect;
549 // Copy all allocation orders, filter out foreign registers from the larger
551 Orders.resize(Super.Orders.size());
552 for (unsigned i = 0, ie = Super.Orders.size(); i != ie; ++i)
553 for (unsigned j = 0, je = Super.Orders[i].size(); j != je; ++j)
554 if (contains(RegBank.getReg(Super.Orders[i][j])))
555 Orders[i].push_back(Super.Orders[i][j]);
558 bool CodeGenRegisterClass::contains(const CodeGenRegister *Reg) const {
559 return Members.count(Reg);
563 raw_ostream &operator<<(raw_ostream &OS, const CodeGenRegisterClass::Key &K) {
564 OS << "{ S=" << K.SpillSize << ", A=" << K.SpillAlignment;
565 for (CodeGenRegister::Set::const_iterator I = K.Members->begin(),
566 E = K.Members->end(); I != E; ++I)
567 OS << ", " << (*I)->getName();
572 // This is a simple lexicographical order that can be used to search for sets.
573 // It is not the same as the topological order provided by TopoOrderRC.
574 bool CodeGenRegisterClass::Key::
575 operator<(const CodeGenRegisterClass::Key &B) const {
576 assert(Members && B.Members);
577 if (*Members != *B.Members)
578 return *Members < *B.Members;
579 if (SpillSize != B.SpillSize)
580 return SpillSize < B.SpillSize;
581 return SpillAlignment < B.SpillAlignment;
584 // Returns true if RC is a strict subclass.
585 // RC is a sub-class of this class if it is a valid replacement for any
586 // instruction operand where a register of this classis required. It must
587 // satisfy these conditions:
589 // 1. All RC registers are also in this.
590 // 2. The RC spill size must not be smaller than our spill size.
591 // 3. RC spill alignment must be compatible with ours.
593 static bool testSubClass(const CodeGenRegisterClass *A,
594 const CodeGenRegisterClass *B) {
595 return A->SpillAlignment && B->SpillAlignment % A->SpillAlignment == 0 &&
596 A->SpillSize <= B->SpillSize &&
597 std::includes(A->getMembers().begin(), A->getMembers().end(),
598 B->getMembers().begin(), B->getMembers().end(),
599 CodeGenRegister::Less());
602 /// Sorting predicate for register classes. This provides a topological
603 /// ordering that arranges all register classes before their sub-classes.
605 /// Register classes with the same registers, spill size, and alignment form a
606 /// clique. They will be ordered alphabetically.
608 static int TopoOrderRC(const void *PA, const void *PB) {
609 const CodeGenRegisterClass *A = *(const CodeGenRegisterClass* const*)PA;
610 const CodeGenRegisterClass *B = *(const CodeGenRegisterClass* const*)PB;
614 // Order by descending set size. Note that the classes' allocation order may
615 // not have been computed yet. The Members set is always vaild.
616 if (A->getMembers().size() > B->getMembers().size())
618 if (A->getMembers().size() < B->getMembers().size())
621 // Order by ascending spill size.
622 if (A->SpillSize < B->SpillSize)
624 if (A->SpillSize > B->SpillSize)
627 // Order by ascending spill alignment.
628 if (A->SpillAlignment < B->SpillAlignment)
630 if (A->SpillAlignment > B->SpillAlignment)
633 // Finally order by name as a tie breaker.
634 return StringRef(A->getName()).compare(B->getName());
637 std::string CodeGenRegisterClass::getQualifiedName() const {
638 if (Namespace.empty())
641 return Namespace + "::" + getName();
644 // Compute sub-classes of all register classes.
645 // Assume the classes are ordered topologically.
646 void CodeGenRegisterClass::computeSubClasses(CodeGenRegBank &RegBank) {
647 ArrayRef<CodeGenRegisterClass*> RegClasses = RegBank.getRegClasses();
649 // Visit backwards so sub-classes are seen first.
650 for (unsigned rci = RegClasses.size(); rci; --rci) {
651 CodeGenRegisterClass &RC = *RegClasses[rci - 1];
652 RC.SubClasses.resize(RegClasses.size());
653 RC.SubClasses.set(RC.EnumValue);
655 // Normally, all subclasses have IDs >= rci, unless RC is part of a clique.
656 for (unsigned s = rci; s != RegClasses.size(); ++s) {
657 if (RC.SubClasses.test(s))
659 CodeGenRegisterClass *SubRC = RegClasses[s];
660 if (!testSubClass(&RC, SubRC))
662 // SubRC is a sub-class. Grap all its sub-classes so we won't have to
664 RC.SubClasses |= SubRC->SubClasses;
667 // Sweep up missed clique members. They will be immediately preceeding RC.
668 for (unsigned s = rci - 1; s && testSubClass(&RC, RegClasses[s - 1]); --s)
669 RC.SubClasses.set(s - 1);
672 // Compute the SuperClasses lists from the SubClasses vectors.
673 for (unsigned rci = 0; rci != RegClasses.size(); ++rci) {
674 const BitVector &SC = RegClasses[rci]->getSubClasses();
675 for (int s = SC.find_first(); s >= 0; s = SC.find_next(s)) {
676 if (unsigned(s) == rci)
678 RegClasses[s]->SuperClasses.push_back(RegClasses[rci]);
682 // With the class hierarchy in place, let synthesized register classes inherit
683 // properties from their closest super-class. The iteration order here can
684 // propagate properties down multiple levels.
685 for (unsigned rci = 0; rci != RegClasses.size(); ++rci)
686 if (!RegClasses[rci]->getDef())
687 RegClasses[rci]->inheritProperties(RegBank);
691 CodeGenRegisterClass::getSuperRegClasses(CodeGenSubRegIndex *SubIdx,
692 BitVector &Out) const {
693 DenseMap<CodeGenSubRegIndex*,
694 SmallPtrSet<CodeGenRegisterClass*, 8> >::const_iterator
695 FindI = SuperRegClasses.find(SubIdx);
696 if (FindI == SuperRegClasses.end())
698 for (SmallPtrSet<CodeGenRegisterClass*, 8>::const_iterator I =
699 FindI->second.begin(), E = FindI->second.end(); I != E; ++I)
700 Out.set((*I)->EnumValue);
703 // Populate a unique sorted list of units from a register set.
704 void CodeGenRegisterClass::buildRegUnitSet(
705 std::vector<unsigned> &RegUnits) const {
706 std::vector<unsigned> TmpUnits;
707 for (RegUnitIterator UnitI(Members); UnitI.isValid(); ++UnitI)
708 TmpUnits.push_back(*UnitI);
709 std::sort(TmpUnits.begin(), TmpUnits.end());
710 std::unique_copy(TmpUnits.begin(), TmpUnits.end(),
711 std::back_inserter(RegUnits));
714 //===----------------------------------------------------------------------===//
716 //===----------------------------------------------------------------------===//
718 CodeGenRegBank::CodeGenRegBank(RecordKeeper &Records) : Records(Records) {
719 // Configure register Sets to understand register classes and tuples.
720 Sets.addFieldExpander("RegisterClass", "MemberList");
721 Sets.addFieldExpander("CalleeSavedRegs", "SaveList");
722 Sets.addExpander("RegisterTuples", new TupleExpander());
724 // Read in the user-defined (named) sub-register indices.
725 // More indices will be synthesized later.
726 std::vector<Record*> SRIs = Records.getAllDerivedDefinitions("SubRegIndex");
727 std::sort(SRIs.begin(), SRIs.end(), LessRecord());
728 NumNamedIndices = SRIs.size();
729 for (unsigned i = 0, e = SRIs.size(); i != e; ++i)
730 getSubRegIdx(SRIs[i]);
731 // Build composite maps from ComposedOf fields.
732 for (unsigned i = 0, e = SubRegIndices.size(); i != e; ++i)
733 SubRegIndices[i]->updateComponents(*this);
735 // Read in the register definitions.
736 std::vector<Record*> Regs = Records.getAllDerivedDefinitions("Register");
737 std::sort(Regs.begin(), Regs.end(), LessRecord());
738 Registers.reserve(Regs.size());
739 // Assign the enumeration values.
740 for (unsigned i = 0, e = Regs.size(); i != e; ++i)
743 // Expand tuples and number the new registers.
744 std::vector<Record*> Tups =
745 Records.getAllDerivedDefinitions("RegisterTuples");
746 for (unsigned i = 0, e = Tups.size(); i != e; ++i) {
747 const std::vector<Record*> *TupRegs = Sets.expand(Tups[i]);
748 for (unsigned j = 0, je = TupRegs->size(); j != je; ++j)
749 getReg((*TupRegs)[j]);
752 // Precompute all sub-register maps now all the registers are known.
753 // This will create Composite entries for all inferred sub-register indices.
755 for (unsigned i = 0, e = Registers.size(); i != e; ++i)
756 Registers[i]->getSubRegs(*this);
758 // Native register units are associated with a leaf register. They've all been
760 NumNativeRegUnits = NumRegUnits;
762 // Read in register class definitions.
763 std::vector<Record*> RCs = Records.getAllDerivedDefinitions("RegisterClass");
765 throw std::string("No 'RegisterClass' subclasses defined!");
767 // Allocate user-defined register classes.
768 RegClasses.reserve(RCs.size());
769 for (unsigned i = 0, e = RCs.size(); i != e; ++i)
770 addToMaps(new CodeGenRegisterClass(*this, RCs[i]));
772 // Infer missing classes to create a full algebra.
773 computeInferredRegisterClasses();
775 // Order register classes topologically and assign enum values.
776 array_pod_sort(RegClasses.begin(), RegClasses.end(), TopoOrderRC);
777 for (unsigned i = 0, e = RegClasses.size(); i != e; ++i)
778 RegClasses[i]->EnumValue = i;
779 CodeGenRegisterClass::computeSubClasses(*this);
782 CodeGenSubRegIndex *CodeGenRegBank::getSubRegIdx(Record *Def) {
783 CodeGenSubRegIndex *&Idx = Def2SubRegIdx[Def];
786 Idx = new CodeGenSubRegIndex(Def, SubRegIndices.size() + 1);
787 SubRegIndices.push_back(Idx);
791 CodeGenRegister *CodeGenRegBank::getReg(Record *Def) {
792 CodeGenRegister *&Reg = Def2Reg[Def];
795 Reg = new CodeGenRegister(Def, Registers.size() + 1);
796 Registers.push_back(Reg);
800 void CodeGenRegBank::addToMaps(CodeGenRegisterClass *RC) {
801 RegClasses.push_back(RC);
803 if (Record *Def = RC->getDef())
804 Def2RC.insert(std::make_pair(Def, RC));
806 // Duplicate classes are rejected by insert().
807 // That's OK, we only care about the properties handled by CGRC::Key.
808 CodeGenRegisterClass::Key K(*RC);
809 Key2RC.insert(std::make_pair(K, RC));
812 // Create a synthetic sub-class if it is missing.
813 CodeGenRegisterClass*
814 CodeGenRegBank::getOrCreateSubClass(const CodeGenRegisterClass *RC,
815 const CodeGenRegister::Set *Members,
817 // Synthetic sub-class has the same size and alignment as RC.
818 CodeGenRegisterClass::Key K(Members, RC->SpillSize, RC->SpillAlignment);
819 RCKeyMap::const_iterator FoundI = Key2RC.find(K);
820 if (FoundI != Key2RC.end())
821 return FoundI->second;
823 // Sub-class doesn't exist, create a new one.
824 CodeGenRegisterClass *NewRC = new CodeGenRegisterClass(Name, K);
829 CodeGenRegisterClass *CodeGenRegBank::getRegClass(Record *Def) {
830 if (CodeGenRegisterClass *RC = Def2RC[Def])
833 throw TGError(Def->getLoc(), "Not a known RegisterClass!");
837 CodeGenRegBank::getCompositeSubRegIndex(CodeGenSubRegIndex *A,
838 CodeGenSubRegIndex *B) {
839 // Look for an existing entry.
840 CodeGenSubRegIndex *Comp = A->compose(B);
844 // None exists, synthesize one.
845 std::string Name = A->getName() + "_then_" + B->getName();
846 Comp = getSubRegIdx(new Record(Name, SMLoc(), Records));
847 A->addComposite(B, Comp);
851 void CodeGenRegBank::computeComposites() {
852 for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
853 CodeGenRegister *Reg1 = Registers[i];
854 const CodeGenRegister::SubRegMap &SRM1 = Reg1->getSubRegs();
855 for (CodeGenRegister::SubRegMap::const_iterator i1 = SRM1.begin(),
856 e1 = SRM1.end(); i1 != e1; ++i1) {
857 CodeGenSubRegIndex *Idx1 = i1->first;
858 CodeGenRegister *Reg2 = i1->second;
859 // Ignore identity compositions.
862 const CodeGenRegister::SubRegMap &SRM2 = Reg2->getSubRegs();
863 // Try composing Idx1 with another SubRegIndex.
864 for (CodeGenRegister::SubRegMap::const_iterator i2 = SRM2.begin(),
865 e2 = SRM2.end(); i2 != e2; ++i2) {
866 CodeGenSubRegIndex *Idx2 = i2->first;
867 CodeGenRegister *Reg3 = i2->second;
868 // Ignore identity compositions.
871 // OK Reg1:IdxPair == Reg3. Find the index with Reg:Idx == Reg3.
872 for (CodeGenRegister::SubRegMap::const_iterator i1d = SRM1.begin(),
873 e1d = SRM1.end(); i1d != e1d; ++i1d) {
874 if (i1d->second == Reg3) {
875 // Conflicting composition? Emit a warning but allow it.
876 if (CodeGenSubRegIndex *Prev = Idx1->addComposite(Idx2, i1d->first))
877 PrintWarning(Twine("SubRegIndex") + Idx1->getQualifiedName() +
878 " and " + Idx2->getQualifiedName() +
879 " compose ambiguously as " + Prev->getQualifiedName() +
880 " or " + i1d->first->getQualifiedName());
887 // We don't care about the difference between (Idx1, Idx2) -> Idx2 and invalid
888 // compositions, so remove any mappings of that form.
889 for (unsigned i = 0, e = SubRegIndices.size(); i != e; ++i)
890 SubRegIndices[i]->cleanComposites();
894 // UberRegSet is a helper class for computeRegUnitWeights. Each UberRegSet is
895 // the transitive closure of the union of overlapping register
896 // classes. Together, the UberRegSets form a partition of the registers. If we
897 // consider overlapping register classes to be connected, then each UberRegSet
898 // is a set of connected components.
900 // An UberRegSet will likely be a horizontal slice of register names of
901 // the same width. Nontrivial subregisters should then be in a separate
902 // UberRegSet. But this property isn't required for valid computation of
903 // register unit weights.
905 // A Weight field caches the max per-register unit weight in each UberRegSet.
907 // A set of SingularDeterminants flags single units of some register in this set
908 // for which the unit weight equals the set weight. These units should not have
909 // their weight increased.
911 CodeGenRegister::Set Regs;
913 CodeGenRegister::RegUnitList SingularDeterminants;
915 UberRegSet(): Weight(0) {}
919 // Partition registers into UberRegSets, where each set is the transitive
920 // closure of the union of overlapping register classes.
922 // UberRegSets[0] is a special non-allocatable set.
923 static void computeUberSets(std::vector<UberRegSet> &UberSets,
924 std::vector<UberRegSet*> &RegSets,
925 CodeGenRegBank &RegBank) {
927 const std::vector<CodeGenRegister*> &Registers = RegBank.getRegisters();
929 // The Register EnumValue is one greater than its index into Registers.
930 assert(Registers.size() == Registers[Registers.size()-1]->EnumValue &&
931 "register enum value mismatch");
933 // For simplicitly make the SetID the same as EnumValue.
934 IntEqClasses UberSetIDs(Registers.size()+1);
935 std::set<unsigned> AllocatableRegs;
936 for (unsigned i = 0, e = RegBank.getRegClasses().size(); i != e; ++i) {
938 CodeGenRegisterClass *RegClass = RegBank.getRegClasses()[i];
939 if (!RegClass->Allocatable)
942 const CodeGenRegister::Set &Regs = RegClass->getMembers();
946 unsigned USetID = UberSetIDs.findLeader((*Regs.begin())->EnumValue);
947 assert(USetID && "register number 0 is invalid");
949 AllocatableRegs.insert((*Regs.begin())->EnumValue);
950 for (CodeGenRegister::Set::const_iterator I = llvm::next(Regs.begin()),
951 E = Regs.end(); I != E; ++I) {
952 AllocatableRegs.insert((*I)->EnumValue);
953 UberSetIDs.join(USetID, (*I)->EnumValue);
956 // Combine non-allocatable regs.
957 for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
958 unsigned RegNum = Registers[i]->EnumValue;
959 if (AllocatableRegs.count(RegNum))
962 UberSetIDs.join(0, RegNum);
964 UberSetIDs.compress();
966 // Make the first UberSet a special unallocatable set.
967 unsigned ZeroID = UberSetIDs[0];
969 // Insert Registers into the UberSets formed by union-find.
970 // Do not resize after this.
971 UberSets.resize(UberSetIDs.getNumClasses());
972 for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
973 const CodeGenRegister *Reg = Registers[i];
974 unsigned USetID = UberSetIDs[Reg->EnumValue];
977 else if (USetID == ZeroID)
980 UberRegSet *USet = &UberSets[USetID];
981 USet->Regs.insert(Reg);
986 // Recompute each UberSet weight after changing unit weights.
987 static void computeUberWeights(std::vector<UberRegSet> &UberSets,
988 CodeGenRegBank &RegBank) {
989 // Skip the first unallocatable set.
990 for (std::vector<UberRegSet>::iterator I = llvm::next(UberSets.begin()),
991 E = UberSets.end(); I != E; ++I) {
993 // Initialize all unit weights in this set, and remember the max units/reg.
994 const CodeGenRegister *Reg = 0;
995 unsigned MaxWeight = 0, Weight = 0;
996 for (RegUnitIterator UnitI(I->Regs); UnitI.isValid(); ++UnitI) {
997 if (Reg != UnitI.getReg()) {
998 if (Weight > MaxWeight)
1000 Reg = UnitI.getReg();
1003 unsigned UWeight = RegBank.getRegUnitWeight(*UnitI);
1006 RegBank.increaseRegUnitWeight(*UnitI, UWeight);
1010 if (Weight > MaxWeight)
1013 // Update the set weight.
1014 I->Weight = MaxWeight;
1016 // Find singular determinants.
1017 for (CodeGenRegister::Set::iterator RegI = I->Regs.begin(),
1018 RegE = I->Regs.end(); RegI != RegE; ++RegI) {
1019 if ((*RegI)->getRegUnits().size() == 1
1020 && (*RegI)->getWeight(RegBank) == I->Weight)
1021 mergeRegUnits(I->SingularDeterminants, (*RegI)->getRegUnits());
1026 // normalizeWeight is a computeRegUnitWeights helper that adjusts the weight of
1027 // a register and its subregisters so that they have the same weight as their
1028 // UberSet. Self-recursion processes the subregister tree in postorder so
1029 // subregisters are normalized first.
1032 // - creates new adopted register units
1033 // - causes superregisters to inherit adopted units
1034 // - increases the weight of "singular" units
1035 // - induces recomputation of UberWeights.
1036 static bool normalizeWeight(CodeGenRegister *Reg,
1037 std::vector<UberRegSet> &UberSets,
1038 std::vector<UberRegSet*> &RegSets,
1039 CodeGenRegister::RegUnitList &NormalUnits,
1040 CodeGenRegBank &RegBank) {
1041 bool Changed = false;
1042 const CodeGenRegister::SubRegMap &SRM = Reg->getSubRegs();
1043 for (CodeGenRegister::SubRegMap::const_iterator SRI = SRM.begin(),
1044 SRE = SRM.end(); SRI != SRE; ++SRI) {
1045 if (SRI->second == Reg)
1046 continue; // self-cycles happen
1049 normalizeWeight(SRI->second, UberSets, RegSets, NormalUnits, RegBank);
1051 // Postorder register normalization.
1053 // Inherit register units newly adopted by subregisters.
1054 if (Reg->inheritRegUnits(RegBank))
1055 computeUberWeights(UberSets, RegBank);
1057 // Check if this register is too skinny for its UberRegSet.
1058 UberRegSet *UberSet = RegSets[RegBank.getRegIndex(Reg)];
1060 unsigned RegWeight = Reg->getWeight(RegBank);
1061 if (UberSet->Weight > RegWeight) {
1062 // A register unit's weight can be adjusted only if it is the singular unit
1063 // for this register, has not been used to normalize a subregister's set,
1064 // and has not already been used to singularly determine this UberRegSet.
1065 unsigned AdjustUnit = Reg->getRegUnits().front();
1066 if (Reg->getRegUnits().size() != 1
1067 || hasRegUnit(NormalUnits, AdjustUnit)
1068 || hasRegUnit(UberSet->SingularDeterminants, AdjustUnit)) {
1069 // We don't have an adjustable unit, so adopt a new one.
1070 AdjustUnit = RegBank.newRegUnit(UberSet->Weight - RegWeight);
1071 Reg->adoptRegUnit(AdjustUnit);
1072 // Adopting a unit does not immediately require recomputing set weights.
1075 // Adjust the existing single unit.
1076 RegBank.increaseRegUnitWeight(AdjustUnit, UberSet->Weight - RegWeight);
1077 // The unit may be shared among sets and registers within this set.
1078 computeUberWeights(UberSets, RegBank);
1083 // Mark these units normalized so superregisters can't change their weights.
1084 mergeRegUnits(NormalUnits, Reg->getRegUnits());
1089 // Compute a weight for each register unit created during getSubRegs.
1091 // The goal is that two registers in the same class will have the same weight,
1092 // where each register's weight is defined as sum of its units' weights.
1093 void CodeGenRegBank::computeRegUnitWeights() {
1094 assert(RegUnitWeights.empty() && "Only initialize RegUnitWeights once");
1096 // Only allocatable units will be initialized to nonzero weight.
1097 RegUnitWeights.resize(NumRegUnits);
1099 std::vector<UberRegSet> UberSets;
1100 std::vector<UberRegSet*> RegSets(Registers.size());
1101 computeUberSets(UberSets, RegSets, *this);
1102 // UberSets and RegSets are now immutable.
1104 computeUberWeights(UberSets, *this);
1106 // Iterate over each Register, normalizing the unit weights until reaching
1108 unsigned NumIters = 0;
1109 for (bool Changed = true; Changed; ++NumIters) {
1110 assert(NumIters <= NumNativeRegUnits && "Runaway register unit weights");
1112 for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
1113 CodeGenRegister::RegUnitList NormalUnits;
1115 normalizeWeight(Registers[i], UberSets, RegSets, NormalUnits, *this);
1120 // Find a set in UniqueSets with the same elements as Set.
1121 // Return an iterator into UniqueSets.
1122 static std::vector<RegUnitSet>::const_iterator
1123 findRegUnitSet(const std::vector<RegUnitSet> &UniqueSets,
1124 const RegUnitSet &Set) {
1125 std::vector<RegUnitSet>::const_iterator
1126 I = UniqueSets.begin(), E = UniqueSets.end();
1128 if (I->Units == Set.Units)
1134 // Return true if the RUSubSet is a subset of RUSuperSet.
1135 static bool isRegUnitSubSet(const std::vector<unsigned> &RUSubSet,
1136 const std::vector<unsigned> &RUSuperSet) {
1137 return std::includes(RUSuperSet.begin(), RUSuperSet.end(),
1138 RUSubSet.begin(), RUSubSet.end());
1141 // Iteratively prune unit sets.
1142 void CodeGenRegBank::pruneUnitSets() {
1143 assert(RegClassUnitSets.empty() && "this invalidates RegClassUnitSets");
1145 // Form an equivalence class of UnitSets with no significant difference.
1146 std::vector<unsigned> SuperSetIDs;
1147 for (unsigned SubIdx = 0, EndIdx = RegUnitSets.size();
1148 SubIdx != EndIdx; ++SubIdx) {
1149 const RegUnitSet &SubSet = RegUnitSets[SubIdx];
1150 unsigned SuperIdx = 0;
1151 for (; SuperIdx != EndIdx; ++SuperIdx) {
1152 if (SuperIdx == SubIdx)
1155 const RegUnitSet &SuperSet = RegUnitSets[SuperIdx];
1156 if (isRegUnitSubSet(SubSet.Units, SuperSet.Units)
1157 && (SubSet.Units.size() + 3 > SuperSet.Units.size())) {
1161 if (SuperIdx == EndIdx)
1162 SuperSetIDs.push_back(SubIdx);
1164 // Populate PrunedUnitSets with each equivalence class's superset.
1165 std::vector<RegUnitSet> PrunedUnitSets(SuperSetIDs.size());
1166 for (unsigned i = 0, e = SuperSetIDs.size(); i != e; ++i) {
1167 unsigned SuperIdx = SuperSetIDs[i];
1168 PrunedUnitSets[i].Name = RegUnitSets[SuperIdx].Name;
1169 PrunedUnitSets[i].Units.swap(RegUnitSets[SuperIdx].Units);
1171 RegUnitSets.swap(PrunedUnitSets);
1174 // Create a RegUnitSet for each RegClass that contains all units in the class
1175 // including adopted units that are necessary to model register pressure. Then
1176 // iteratively compute RegUnitSets such that the union of any two overlapping
1177 // RegUnitSets is repreresented.
1179 // RegisterInfoEmitter will map each RegClass to its RegUnitClass and any
1180 // RegUnitSet that is a superset of that RegUnitClass.
1181 void CodeGenRegBank::computeRegUnitSets() {
1183 // Compute a unique RegUnitSet for each RegClass.
1184 const ArrayRef<CodeGenRegisterClass*> &RegClasses = getRegClasses();
1185 unsigned NumRegClasses = RegClasses.size();
1186 for (unsigned RCIdx = 0, RCEnd = NumRegClasses; RCIdx != RCEnd; ++RCIdx) {
1187 if (!RegClasses[RCIdx]->Allocatable)
1190 // Speculatively grow the RegUnitSets to hold the new set.
1191 RegUnitSets.resize(RegUnitSets.size() + 1);
1192 RegUnitSets.back().Name = RegClasses[RCIdx]->getName();
1194 // Compute a sorted list of units in this class.
1195 RegClasses[RCIdx]->buildRegUnitSet(RegUnitSets.back().Units);
1197 // Find an existing RegUnitSet.
1198 std::vector<RegUnitSet>::const_iterator SetI =
1199 findRegUnitSet(RegUnitSets, RegUnitSets.back());
1200 if (SetI != llvm::prior(RegUnitSets.end()))
1201 RegUnitSets.pop_back();
1204 // Iteratively prune unit sets.
1207 // Iterate over all unit sets, including new ones added by this loop.
1208 unsigned NumRegUnitSubSets = RegUnitSets.size();
1209 for (unsigned Idx = 0, EndIdx = RegUnitSets.size(); Idx != EndIdx; ++Idx) {
1210 // In theory, this is combinatorial. In practice, it needs to be bounded
1211 // by a small number of sets for regpressure to be efficient.
1212 // If the assert is hit, we need to implement pruning.
1213 assert(Idx < (2*NumRegUnitSubSets) && "runaway unit set inference");
1215 // Compare new sets with all original classes.
1216 for (unsigned SearchIdx = (Idx >= NumRegUnitSubSets) ? 0 : Idx+1;
1217 SearchIdx != EndIdx; ++SearchIdx) {
1218 std::set<unsigned> Intersection;
1219 std::set_intersection(RegUnitSets[Idx].Units.begin(),
1220 RegUnitSets[Idx].Units.end(),
1221 RegUnitSets[SearchIdx].Units.begin(),
1222 RegUnitSets[SearchIdx].Units.end(),
1223 std::inserter(Intersection, Intersection.begin()));
1224 if (Intersection.empty())
1227 // Speculatively grow the RegUnitSets to hold the new set.
1228 RegUnitSets.resize(RegUnitSets.size() + 1);
1229 RegUnitSets.back().Name =
1230 RegUnitSets[Idx].Name + "+" + RegUnitSets[SearchIdx].Name;
1232 std::set_union(RegUnitSets[Idx].Units.begin(),
1233 RegUnitSets[Idx].Units.end(),
1234 RegUnitSets[SearchIdx].Units.begin(),
1235 RegUnitSets[SearchIdx].Units.end(),
1236 std::inserter(RegUnitSets.back().Units,
1237 RegUnitSets.back().Units.begin()));
1239 // Find an existing RegUnitSet, or add the union to the unique sets.
1240 std::vector<RegUnitSet>::const_iterator SetI =
1241 findRegUnitSet(RegUnitSets, RegUnitSets.back());
1242 if (SetI != llvm::prior(RegUnitSets.end()))
1243 RegUnitSets.pop_back();
1247 // Iteratively prune unit sets after inferring supersets.
1250 // For each register class, list the UnitSets that are supersets.
1251 RegClassUnitSets.resize(NumRegClasses);
1252 for (unsigned RCIdx = 0, RCEnd = NumRegClasses; RCIdx != RCEnd; ++RCIdx) {
1253 if (!RegClasses[RCIdx]->Allocatable)
1256 // Recompute the sorted list of units in this class.
1257 std::vector<unsigned> RegUnits;
1258 RegClasses[RCIdx]->buildRegUnitSet(RegUnits);
1260 // Don't increase pressure for unallocatable regclasses.
1261 if (RegUnits.empty())
1264 // Find all supersets.
1265 for (unsigned USIdx = 0, USEnd = RegUnitSets.size();
1266 USIdx != USEnd; ++USIdx) {
1267 if (isRegUnitSubSet(RegUnits, RegUnitSets[USIdx].Units))
1268 RegClassUnitSets[RCIdx].push_back(USIdx);
1270 assert(!RegClassUnitSets[RCIdx].empty() && "missing unit set for regclass");
1274 // Compute sets of overlapping registers.
1276 // The standard set is all super-registers and all sub-registers, but the
1277 // target description can add arbitrary overlapping registers via the 'Aliases'
1278 // field. This complicates things, but we can compute overlapping sets using
1279 // the following rules:
1281 // 1. The relation overlap(A, B) is reflexive and symmetric but not transitive.
1283 // 2. overlap(A, B) implies overlap(A, S) for all S in supers(B).
1287 // overlap(A, B) iff there exists:
1288 // A' in { A, subregs(A) } and B' in { B, subregs(B) } such that:
1289 // A' = B' or A' in aliases(B') or B' in aliases(A').
1291 // Here subregs(A) is the full flattened sub-register set returned by
1292 // A.getSubRegs() while aliases(A) is simply the special 'Aliases' field in the
1293 // description of register A.
1295 // This also implies that registers with a common sub-register are considered
1296 // overlapping. This can happen when forming register pairs:
1302 // In this case, we will infer an overlap between P0 and P1 because of the
1303 // shared sub-register R1. There is no overlap between P0 and P2.
1305 void CodeGenRegBank::
1306 computeOverlaps(std::map<const CodeGenRegister*, CodeGenRegister::Set> &Map) {
1307 assert(Map.empty());
1309 // Collect overlaps that don't follow from rule 2.
1310 for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
1311 CodeGenRegister *Reg = Registers[i];
1312 CodeGenRegister::Set &Overlaps = Map[Reg];
1314 // Reg overlaps itself.
1315 Overlaps.insert(Reg);
1317 // All super-registers overlap.
1318 const CodeGenRegister::SuperRegList &Supers = Reg->getSuperRegs();
1319 Overlaps.insert(Supers.begin(), Supers.end());
1321 // Form symmetrical relations from the special Aliases[] lists.
1322 std::vector<Record*> RegList = Reg->TheDef->getValueAsListOfDefs("Aliases");
1323 for (unsigned i2 = 0, e2 = RegList.size(); i2 != e2; ++i2) {
1324 CodeGenRegister *Reg2 = getReg(RegList[i2]);
1325 CodeGenRegister::Set &Overlaps2 = Map[Reg2];
1326 const CodeGenRegister::SuperRegList &Supers2 = Reg2->getSuperRegs();
1327 // Reg overlaps Reg2 which implies it overlaps supers(Reg2).
1328 Overlaps.insert(Reg2);
1329 Overlaps.insert(Supers2.begin(), Supers2.end());
1330 Overlaps2.insert(Reg);
1331 Overlaps2.insert(Supers.begin(), Supers.end());
1335 // Apply rule 2. and inherit all sub-register overlaps.
1336 for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
1337 CodeGenRegister *Reg = Registers[i];
1338 CodeGenRegister::Set &Overlaps = Map[Reg];
1339 const CodeGenRegister::SubRegMap &SRM = Reg->getSubRegs();
1340 for (CodeGenRegister::SubRegMap::const_iterator i2 = SRM.begin(),
1341 e2 = SRM.end(); i2 != e2; ++i2) {
1342 CodeGenRegister::Set &Overlaps2 = Map[i2->second];
1343 Overlaps.insert(Overlaps2.begin(), Overlaps2.end());
1348 void CodeGenRegBank::computeDerivedInfo() {
1349 computeComposites();
1351 // Compute a weight for each register unit created during getSubRegs.
1352 // This may create adopted register units (with unit # >= NumNativeRegUnits).
1353 computeRegUnitWeights();
1355 // Compute a unique set of RegUnitSets. One for each RegClass and inferred
1356 // supersets for the union of overlapping sets.
1357 computeRegUnitSets();
1361 // Synthesize missing register class intersections.
1363 // Make sure that sub-classes of RC exists such that getCommonSubClass(RC, X)
1364 // returns a maximal register class for all X.
1366 void CodeGenRegBank::inferCommonSubClass(CodeGenRegisterClass *RC) {
1367 for (unsigned rci = 0, rce = RegClasses.size(); rci != rce; ++rci) {
1368 CodeGenRegisterClass *RC1 = RC;
1369 CodeGenRegisterClass *RC2 = RegClasses[rci];
1373 // Compute the set intersection of RC1 and RC2.
1374 const CodeGenRegister::Set &Memb1 = RC1->getMembers();
1375 const CodeGenRegister::Set &Memb2 = RC2->getMembers();
1376 CodeGenRegister::Set Intersection;
1377 std::set_intersection(Memb1.begin(), Memb1.end(),
1378 Memb2.begin(), Memb2.end(),
1379 std::inserter(Intersection, Intersection.begin()),
1380 CodeGenRegister::Less());
1382 // Skip disjoint class pairs.
1383 if (Intersection.empty())
1386 // If RC1 and RC2 have different spill sizes or alignments, use the
1387 // larger size for sub-classing. If they are equal, prefer RC1.
1388 if (RC2->SpillSize > RC1->SpillSize ||
1389 (RC2->SpillSize == RC1->SpillSize &&
1390 RC2->SpillAlignment > RC1->SpillAlignment))
1391 std::swap(RC1, RC2);
1393 getOrCreateSubClass(RC1, &Intersection,
1394 RC1->getName() + "_and_" + RC2->getName());
1399 // Synthesize missing sub-classes for getSubClassWithSubReg().
1401 // Make sure that the set of registers in RC with a given SubIdx sub-register
1402 // form a register class. Update RC->SubClassWithSubReg.
1404 void CodeGenRegBank::inferSubClassWithSubReg(CodeGenRegisterClass *RC) {
1405 // Map SubRegIndex to set of registers in RC supporting that SubRegIndex.
1406 typedef std::map<CodeGenSubRegIndex*, CodeGenRegister::Set,
1407 CodeGenSubRegIndex::Less> SubReg2SetMap;
1409 // Compute the set of registers supporting each SubRegIndex.
1410 SubReg2SetMap SRSets;
1411 for (CodeGenRegister::Set::const_iterator RI = RC->getMembers().begin(),
1412 RE = RC->getMembers().end(); RI != RE; ++RI) {
1413 const CodeGenRegister::SubRegMap &SRM = (*RI)->getSubRegs();
1414 for (CodeGenRegister::SubRegMap::const_iterator I = SRM.begin(),
1415 E = SRM.end(); I != E; ++I)
1416 SRSets[I->first].insert(*RI);
1419 // Find matching classes for all SRSets entries. Iterate in SubRegIndex
1420 // numerical order to visit synthetic indices last.
1421 for (unsigned sri = 0, sre = SubRegIndices.size(); sri != sre; ++sri) {
1422 CodeGenSubRegIndex *SubIdx = SubRegIndices[sri];
1423 SubReg2SetMap::const_iterator I = SRSets.find(SubIdx);
1424 // Unsupported SubRegIndex. Skip it.
1425 if (I == SRSets.end())
1427 // In most cases, all RC registers support the SubRegIndex.
1428 if (I->second.size() == RC->getMembers().size()) {
1429 RC->setSubClassWithSubReg(SubIdx, RC);
1432 // This is a real subset. See if we have a matching class.
1433 CodeGenRegisterClass *SubRC =
1434 getOrCreateSubClass(RC, &I->second,
1435 RC->getName() + "_with_" + I->first->getName());
1436 RC->setSubClassWithSubReg(SubIdx, SubRC);
1441 // Synthesize missing sub-classes of RC for getMatchingSuperRegClass().
1443 // Create sub-classes of RC such that getMatchingSuperRegClass(RC, SubIdx, X)
1444 // has a maximal result for any SubIdx and any X >= FirstSubRegRC.
1447 void CodeGenRegBank::inferMatchingSuperRegClass(CodeGenRegisterClass *RC,
1448 unsigned FirstSubRegRC) {
1449 SmallVector<std::pair<const CodeGenRegister*,
1450 const CodeGenRegister*>, 16> SSPairs;
1452 // Iterate in SubRegIndex numerical order to visit synthetic indices last.
1453 for (unsigned sri = 0, sre = SubRegIndices.size(); sri != sre; ++sri) {
1454 CodeGenSubRegIndex *SubIdx = SubRegIndices[sri];
1455 // Skip indexes that aren't fully supported by RC's registers. This was
1456 // computed by inferSubClassWithSubReg() above which should have been
1458 if (RC->getSubClassWithSubReg(SubIdx) != RC)
1461 // Build list of (Super, Sub) pairs for this SubIdx.
1463 for (CodeGenRegister::Set::const_iterator RI = RC->getMembers().begin(),
1464 RE = RC->getMembers().end(); RI != RE; ++RI) {
1465 const CodeGenRegister *Super = *RI;
1466 const CodeGenRegister *Sub = Super->getSubRegs().find(SubIdx)->second;
1467 assert(Sub && "Missing sub-register");
1468 SSPairs.push_back(std::make_pair(Super, Sub));
1471 // Iterate over sub-register class candidates. Ignore classes created by
1472 // this loop. They will never be useful.
1473 for (unsigned rci = FirstSubRegRC, rce = RegClasses.size(); rci != rce;
1475 CodeGenRegisterClass *SubRC = RegClasses[rci];
1476 // Compute the subset of RC that maps into SubRC.
1477 CodeGenRegister::Set SubSet;
1478 for (unsigned i = 0, e = SSPairs.size(); i != e; ++i)
1479 if (SubRC->contains(SSPairs[i].second))
1480 SubSet.insert(SSPairs[i].first);
1483 // RC injects completely into SubRC.
1484 if (SubSet.size() == SSPairs.size()) {
1485 SubRC->addSuperRegClass(SubIdx, RC);
1488 // Only a subset of RC maps into SubRC. Make sure it is represented by a
1490 getOrCreateSubClass(RC, &SubSet, RC->getName() +
1491 "_with_" + SubIdx->getName() +
1492 "_in_" + SubRC->getName());
1499 // Infer missing register classes.
1501 void CodeGenRegBank::computeInferredRegisterClasses() {
1502 // When this function is called, the register classes have not been sorted
1503 // and assigned EnumValues yet. That means getSubClasses(),
1504 // getSuperClasses(), and hasSubClass() functions are defunct.
1505 unsigned FirstNewRC = RegClasses.size();
1507 // Visit all register classes, including the ones being added by the loop.
1508 for (unsigned rci = 0; rci != RegClasses.size(); ++rci) {
1509 CodeGenRegisterClass *RC = RegClasses[rci];
1511 // Synthesize answers for getSubClassWithSubReg().
1512 inferSubClassWithSubReg(RC);
1514 // Synthesize answers for getCommonSubClass().
1515 inferCommonSubClass(RC);
1517 // Synthesize answers for getMatchingSuperRegClass().
1518 inferMatchingSuperRegClass(RC);
1520 // New register classes are created while this loop is running, and we need
1521 // to visit all of them. I particular, inferMatchingSuperRegClass needs
1522 // to match old super-register classes with sub-register classes created
1523 // after inferMatchingSuperRegClass was called. At this point,
1524 // inferMatchingSuperRegClass has checked SuperRC = [0..rci] with SubRC =
1525 // [0..FirstNewRC). We need to cover SubRC = [FirstNewRC..rci].
1526 if (rci + 1 == FirstNewRC) {
1527 unsigned NextNewRC = RegClasses.size();
1528 for (unsigned rci2 = 0; rci2 != FirstNewRC; ++rci2)
1529 inferMatchingSuperRegClass(RegClasses[rci2], FirstNewRC);
1530 FirstNewRC = NextNewRC;
1535 /// getRegisterClassForRegister - Find the register class that contains the
1536 /// specified physical register. If the register is not in a register class,
1537 /// return null. If the register is in multiple classes, and the classes have a
1538 /// superset-subset relationship and the same set of types, return the
1539 /// superclass. Otherwise return null.
1540 const CodeGenRegisterClass*
1541 CodeGenRegBank::getRegClassForRegister(Record *R) {
1542 const CodeGenRegister *Reg = getReg(R);
1543 ArrayRef<CodeGenRegisterClass*> RCs = getRegClasses();
1544 const CodeGenRegisterClass *FoundRC = 0;
1545 for (unsigned i = 0, e = RCs.size(); i != e; ++i) {
1546 const CodeGenRegisterClass &RC = *RCs[i];
1547 if (!RC.contains(Reg))
1550 // If this is the first class that contains the register,
1551 // make a note of it and go on to the next class.
1557 // If a register's classes have different types, return null.
1558 if (RC.getValueTypes() != FoundRC->getValueTypes())
1561 // Check to see if the previously found class that contains
1562 // the register is a subclass of the current class. If so,
1563 // prefer the superclass.
1564 if (RC.hasSubClass(FoundRC)) {
1569 // Check to see if the previously found class that contains
1570 // the register is a superclass of the current class. If so,
1571 // prefer the superclass.
1572 if (FoundRC->hasSubClass(&RC))
1575 // Multiple classes, and neither is a superclass of the other.
1582 BitVector CodeGenRegBank::computeCoveredRegisters(ArrayRef<Record*> Regs) {
1583 SetVector<const CodeGenRegister*> Set;
1585 // First add Regs with all sub-registers.
1586 for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
1587 CodeGenRegister *Reg = getReg(Regs[i]);
1588 if (Set.insert(Reg))
1589 // Reg is new, add all sub-registers.
1590 // The pre-ordering is not important here.
1591 Reg->addSubRegsPreOrder(Set, *this);
1594 // Second, find all super-registers that are completely covered by the set.
1595 for (unsigned i = 0; i != Set.size(); ++i) {
1596 const CodeGenRegister::SuperRegList &SR = Set[i]->getSuperRegs();
1597 for (unsigned j = 0, e = SR.size(); j != e; ++j) {
1598 const CodeGenRegister *Super = SR[j];
1599 if (!Super->CoveredBySubRegs || Set.count(Super))
1601 // This new super-register is covered by its sub-registers.
1602 bool AllSubsInSet = true;
1603 const CodeGenRegister::SubRegMap &SRM = Super->getSubRegs();
1604 for (CodeGenRegister::SubRegMap::const_iterator I = SRM.begin(),
1605 E = SRM.end(); I != E; ++I)
1606 if (!Set.count(I->second)) {
1607 AllSubsInSet = false;
1610 // All sub-registers in Set, add Super as well.
1611 // We will visit Super later to recheck its super-registers.
1617 // Convert to BitVector.
1618 BitVector BV(Registers.size() + 1);
1619 for (unsigned i = 0, e = Set.size(); i != e; ++i)
1620 BV.set(Set[i]->EnumValue);