| //===- DAGISelMatcherOpt.cpp - Optimize a DAG Matcher ---------------------===// | |
| // | |
| // The LLVM Compiler Infrastructure | |
| // | |
| // This file is distributed under the University of Illinois Open Source | |
| // License. See LICENSE.TXT for details. | |
| // | |
| //===----------------------------------------------------------------------===// | |
| // | |
| // This file implements the DAG Matcher optimizer. | |
| // | |
| //===----------------------------------------------------------------------===// | |
| #include "DAGISelMatcher.h" | |
| #include "CodeGenDAGPatterns.h" | |
| #include "llvm/ADT/StringSet.h" | |
| #include "llvm/Support/Debug.h" | |
| #include "llvm/Support/raw_ostream.h" | |
| using namespace llvm; | |
| #define DEBUG_TYPE "isel-opt" | |
| /// ContractNodes - Turn multiple matcher node patterns like 'MoveChild+Record' | |
| /// into single compound nodes like RecordChild. | |
| static void ContractNodes(std::unique_ptr<Matcher> &MatcherPtr, | |
| const CodeGenDAGPatterns &CGP) { | |
| // If we reached the end of the chain, we're done. | |
| Matcher *N = MatcherPtr.get(); | |
| if (!N) return; | |
| // If we have a scope node, walk down all of the children. | |
| if (ScopeMatcher *Scope = dyn_cast<ScopeMatcher>(N)) { | |
| for (unsigned i = 0, e = Scope->getNumChildren(); i != e; ++i) { | |
| std::unique_ptr<Matcher> Child(Scope->takeChild(i)); | |
| ContractNodes(Child, CGP); | |
| Scope->resetChild(i, Child.release()); | |
| } | |
| return; | |
| } | |
| // If we found a movechild node with a node that comes in a 'foochild' form, | |
| // transform it. | |
| if (MoveChildMatcher *MC = dyn_cast<MoveChildMatcher>(N)) { | |
| Matcher *New = nullptr; | |
| if (RecordMatcher *RM = dyn_cast<RecordMatcher>(MC->getNext())) | |
| if (MC->getChildNo() < 8) // Only have RecordChild0...7 | |
| New = new RecordChildMatcher(MC->getChildNo(), RM->getWhatFor(), | |
| RM->getResultNo()); | |
| if (CheckTypeMatcher *CT = dyn_cast<CheckTypeMatcher>(MC->getNext())) | |
| if (MC->getChildNo() < 8 && // Only have CheckChildType0...7 | |
| CT->getResNo() == 0) // CheckChildType checks res #0 | |
| New = new CheckChildTypeMatcher(MC->getChildNo(), CT->getType()); | |
| if (CheckSameMatcher *CS = dyn_cast<CheckSameMatcher>(MC->getNext())) | |
| if (MC->getChildNo() < 4) // Only have CheckChildSame0...3 | |
| New = new CheckChildSameMatcher(MC->getChildNo(), CS->getMatchNumber()); | |
| if (CheckIntegerMatcher *CS = dyn_cast<CheckIntegerMatcher>(MC->getNext())) | |
| if (MC->getChildNo() < 5) // Only have CheckChildInteger0...4 | |
| New = new CheckChildIntegerMatcher(MC->getChildNo(), CS->getValue()); | |
| if (New) { | |
| // Insert the new node. | |
| New->setNext(MatcherPtr.release()); | |
| MatcherPtr.reset(New); | |
| // Remove the old one. | |
| MC->setNext(MC->getNext()->takeNext()); | |
| return ContractNodes(MatcherPtr, CGP); | |
| } | |
| } | |
| // Zap movechild -> moveparent. | |
| if (MoveChildMatcher *MC = dyn_cast<MoveChildMatcher>(N)) | |
| if (MoveParentMatcher *MP = | |
| dyn_cast<MoveParentMatcher>(MC->getNext())) { | |
| MatcherPtr.reset(MP->takeNext()); | |
| return ContractNodes(MatcherPtr, CGP); | |
| } | |
| // Turn EmitNode->CompleteMatch into MorphNodeTo if we can. | |
| if (EmitNodeMatcher *EN = dyn_cast<EmitNodeMatcher>(N)) | |
| if (CompleteMatchMatcher *CM = | |
| dyn_cast<CompleteMatchMatcher>(EN->getNext())) { | |
| // We can only use MorphNodeTo if the result values match up. | |
| unsigned RootResultFirst = EN->getFirstResultSlot(); | |
| bool ResultsMatch = true; | |
| for (unsigned i = 0, e = CM->getNumResults(); i != e; ++i) | |
| if (CM->getResult(i) != RootResultFirst+i) | |
| ResultsMatch = false; | |
| // If the selected node defines a subset of the glue/chain results, we | |
| // can't use MorphNodeTo. For example, we can't use MorphNodeTo if the | |
| // matched pattern has a chain but the root node doesn't. | |
| const PatternToMatch &Pattern = CM->getPattern(); | |
| if (!EN->hasChain() && | |
| Pattern.getSrcPattern()->NodeHasProperty(SDNPHasChain, CGP)) | |
| ResultsMatch = false; | |
| // If the matched node has glue and the output root doesn't, we can't | |
| // use MorphNodeTo. | |
| // | |
| // NOTE: Strictly speaking, we don't have to check for glue here | |
| // because the code in the pattern generator doesn't handle it right. We | |
| // do it anyway for thoroughness. | |
| if (!EN->hasOutFlag() && | |
| Pattern.getSrcPattern()->NodeHasProperty(SDNPOutGlue, CGP)) | |
| ResultsMatch = false; | |
| // If the root result node defines more results than the source root node | |
| // *and* has a chain or glue input, then we can't match it because it | |
| // would end up replacing the extra result with the chain/glue. | |
| #if 0 | |
| if ((EN->hasGlue() || EN->hasChain()) && | |
| EN->getNumNonChainGlueVTs() > ... need to get no results reliably ...) | |
| ResultMatch = false; | |
| #endif | |
| if (ResultsMatch) { | |
| const SmallVectorImpl<MVT::SimpleValueType> &VTs = EN->getVTList(); | |
| const SmallVectorImpl<unsigned> &Operands = EN->getOperandList(); | |
| MatcherPtr.reset(new MorphNodeToMatcher(EN->getOpcodeName(), | |
| VTs, Operands, | |
| EN->hasChain(), EN->hasInFlag(), | |
| EN->hasOutFlag(), | |
| EN->hasMemRefs(), | |
| EN->getNumFixedArityOperands(), | |
| Pattern)); | |
| return; | |
| } | |
| // FIXME2: Kill off all the SelectionDAG::SelectNodeTo and getMachineNode | |
| // variants. | |
| } | |
| ContractNodes(N->getNextPtr(), CGP); | |
| // If we have a CheckType/CheckChildType/Record node followed by a | |
| // CheckOpcode, invert the two nodes. We prefer to do structural checks | |
| // before type checks, as this opens opportunities for factoring on targets | |
| // like X86 where many operations are valid on multiple types. | |
| if ((isa<CheckTypeMatcher>(N) || isa<CheckChildTypeMatcher>(N) || | |
| isa<RecordMatcher>(N)) && | |
| isa<CheckOpcodeMatcher>(N->getNext())) { | |
| // Unlink the two nodes from the list. | |
| Matcher *CheckType = MatcherPtr.release(); | |
| Matcher *CheckOpcode = CheckType->takeNext(); | |
| Matcher *Tail = CheckOpcode->takeNext(); | |
| // Relink them. | |
| MatcherPtr.reset(CheckOpcode); | |
| CheckOpcode->setNext(CheckType); | |
| CheckType->setNext(Tail); | |
| return ContractNodes(MatcherPtr, CGP); | |
| } | |
| } | |
| /// FindNodeWithKind - Scan a series of matchers looking for a matcher with a | |
| /// specified kind. Return null if we didn't find one otherwise return the | |
| /// matcher. | |
| static Matcher *FindNodeWithKind(Matcher *M, Matcher::KindTy Kind) { | |
| for (; M; M = M->getNext()) | |
| if (M->getKind() == Kind) | |
| return M; | |
| return nullptr; | |
| } | |
| /// FactorNodes - Turn matches like this: | |
| /// Scope | |
| /// OPC_CheckType i32 | |
| /// ABC | |
| /// OPC_CheckType i32 | |
| /// XYZ | |
| /// into: | |
| /// OPC_CheckType i32 | |
| /// Scope | |
| /// ABC | |
| /// XYZ | |
| /// | |
| static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) { | |
| // Look for a push node. Iterates instead of recurses to reduce stack usage. | |
| ScopeMatcher *Scope = nullptr; | |
| std::unique_ptr<Matcher> *RebindableMatcherPtr = &InputMatcherPtr; | |
| while (!Scope) { | |
| // If we reached the end of the chain, we're done. | |
| Matcher *N = RebindableMatcherPtr->get(); | |
| if (!N) return; | |
| // If this is not a push node, just scan for one. | |
| Scope = dyn_cast<ScopeMatcher>(N); | |
| if (!Scope) | |
| RebindableMatcherPtr = &(N->getNextPtr()); | |
| } | |
| std::unique_ptr<Matcher> &MatcherPtr = *RebindableMatcherPtr; | |
| // Okay, pull together the children of the scope node into a vector so we can | |
| // inspect it more easily. | |
| SmallVector<Matcher*, 32> OptionsToMatch; | |
| for (unsigned i = 0, e = Scope->getNumChildren(); i != e; ++i) { | |
| // Factor the subexpression. | |
| std::unique_ptr<Matcher> Child(Scope->takeChild(i)); | |
| FactorNodes(Child); | |
| if (Child) { | |
| // If the child is a ScopeMatcher we can just merge its contents. | |
| if (auto *SM = dyn_cast<ScopeMatcher>(Child.get())) { | |
| for (unsigned j = 0, e = SM->getNumChildren(); j != e; ++j) | |
| OptionsToMatch.push_back(SM->takeChild(j)); | |
| } else { | |
| OptionsToMatch.push_back(Child.release()); | |
| } | |
| } | |
| } | |
| SmallVector<Matcher*, 32> NewOptionsToMatch; | |
| // Loop over options to match, merging neighboring patterns with identical | |
| // starting nodes into a shared matcher. | |
| for (unsigned OptionIdx = 0, e = OptionsToMatch.size(); OptionIdx != e;) { | |
| // Find the set of matchers that start with this node. | |
| Matcher *Optn = OptionsToMatch[OptionIdx++]; | |
| if (OptionIdx == e) { | |
| NewOptionsToMatch.push_back(Optn); | |
| continue; | |
| } | |
| // See if the next option starts with the same matcher. If the two | |
| // neighbors *do* start with the same matcher, we can factor the matcher out | |
| // of at least these two patterns. See what the maximal set we can merge | |
| // together is. | |
| SmallVector<Matcher*, 8> EqualMatchers; | |
| EqualMatchers.push_back(Optn); | |
| // Factor all of the known-equal matchers after this one into the same | |
| // group. | |
| while (OptionIdx != e && OptionsToMatch[OptionIdx]->isEqual(Optn)) | |
| EqualMatchers.push_back(OptionsToMatch[OptionIdx++]); | |
| // If we found a non-equal matcher, see if it is contradictory with the | |
| // current node. If so, we know that the ordering relation between the | |
| // current sets of nodes and this node don't matter. Look past it to see if | |
| // we can merge anything else into this matching group. | |
| unsigned Scan = OptionIdx; | |
| while (1) { | |
| // If we ran out of stuff to scan, we're done. | |
| if (Scan == e) break; | |
| Matcher *ScanMatcher = OptionsToMatch[Scan]; | |
| // If we found an entry that matches out matcher, merge it into the set to | |
| // handle. | |
| if (Optn->isEqual(ScanMatcher)) { | |
| // If is equal after all, add the option to EqualMatchers and remove it | |
| // from OptionsToMatch. | |
| EqualMatchers.push_back(ScanMatcher); | |
| OptionsToMatch.erase(OptionsToMatch.begin()+Scan); | |
| --e; | |
| continue; | |
| } | |
| // If the option we're checking for contradicts the start of the list, | |
| // skip over it. | |
| if (Optn->isContradictory(ScanMatcher)) { | |
| ++Scan; | |
| continue; | |
| } | |
| // If we're scanning for a simple node, see if it occurs later in the | |
| // sequence. If so, and if we can move it up, it might be contradictory | |
| // or the same as what we're looking for. If so, reorder it. | |
| if (Optn->isSimplePredicateOrRecordNode()) { | |
| Matcher *M2 = FindNodeWithKind(ScanMatcher, Optn->getKind()); | |
| if (M2 && M2 != ScanMatcher && | |
| M2->canMoveBefore(ScanMatcher) && | |
| (M2->isEqual(Optn) || M2->isContradictory(Optn))) { | |
| Matcher *MatcherWithoutM2 = ScanMatcher->unlinkNode(M2); | |
| M2->setNext(MatcherWithoutM2); | |
| OptionsToMatch[Scan] = M2; | |
| continue; | |
| } | |
| } | |
| // Otherwise, we don't know how to handle this entry, we have to bail. | |
| break; | |
| } | |
| if (Scan != e && | |
| // Don't print it's obvious nothing extra could be merged anyway. | |
| Scan+1 != e) { | |
| LLVM_DEBUG(errs() << "Couldn't merge this:\n"; Optn->print(errs(), 4); | |
| errs() << "into this:\n"; | |
| OptionsToMatch[Scan]->print(errs(), 4); | |
| if (Scan + 1 != e) OptionsToMatch[Scan + 1]->printOne(errs()); | |
| if (Scan + 2 < e) OptionsToMatch[Scan + 2]->printOne(errs()); | |
| errs() << "\n"); | |
| } | |
| // If we only found one option starting with this matcher, no factoring is | |
| // possible. | |
| if (EqualMatchers.size() == 1) { | |
| NewOptionsToMatch.push_back(EqualMatchers[0]); | |
| continue; | |
| } | |
| // Factor these checks by pulling the first node off each entry and | |
| // discarding it. Take the first one off the first entry to reuse. | |
| Matcher *Shared = Optn; | |
| Optn = Optn->takeNext(); | |
| EqualMatchers[0] = Optn; | |
| // Remove and delete the first node from the other matchers we're factoring. | |
| for (unsigned i = 1, e = EqualMatchers.size(); i != e; ++i) { | |
| Matcher *Tmp = EqualMatchers[i]->takeNext(); | |
| delete EqualMatchers[i]; | |
| EqualMatchers[i] = Tmp; | |
| } | |
| Shared->setNext(new ScopeMatcher(EqualMatchers)); | |
| // Recursively factor the newly created node. | |
| FactorNodes(Shared->getNextPtr()); | |
| NewOptionsToMatch.push_back(Shared); | |
| } | |
| // If we're down to a single pattern to match, then we don't need this scope | |
| // anymore. | |
| if (NewOptionsToMatch.size() == 1) { | |
| MatcherPtr.reset(NewOptionsToMatch[0]); | |
| return; | |
| } | |
| if (NewOptionsToMatch.empty()) { | |
| MatcherPtr.reset(); | |
| return; | |
| } | |
| // If our factoring failed (didn't achieve anything) see if we can simplify in | |
| // other ways. | |
| // Check to see if all of the leading entries are now opcode checks. If so, | |
| // we can convert this Scope to be a OpcodeSwitch instead. | |
| bool AllOpcodeChecks = true, AllTypeChecks = true; | |
| for (unsigned i = 0, e = NewOptionsToMatch.size(); i != e; ++i) { | |
| // Check to see if this breaks a series of CheckOpcodeMatchers. | |
| if (AllOpcodeChecks && | |
| !isa<CheckOpcodeMatcher>(NewOptionsToMatch[i])) { | |
| #if 0 | |
| if (i > 3) { | |
| errs() << "FAILING OPC #" << i << "\n"; | |
| NewOptionsToMatch[i]->dump(); | |
| } | |
| #endif | |
| AllOpcodeChecks = false; | |
| } | |
| // Check to see if this breaks a series of CheckTypeMatcher's. | |
| if (AllTypeChecks) { | |
| CheckTypeMatcher *CTM = | |
| cast_or_null<CheckTypeMatcher>(FindNodeWithKind(NewOptionsToMatch[i], | |
| Matcher::CheckType)); | |
| if (!CTM || | |
| // iPTR checks could alias any other case without us knowing, don't | |
| // bother with them. | |
| CTM->getType() == MVT::iPTR || | |
| // SwitchType only works for result #0. | |
| CTM->getResNo() != 0 || | |
| // If the CheckType isn't at the start of the list, see if we can move | |
| // it there. | |
| !CTM->canMoveBefore(NewOptionsToMatch[i])) { | |
| #if 0 | |
| if (i > 3 && AllTypeChecks) { | |
| errs() << "FAILING TYPE #" << i << "\n"; | |
| NewOptionsToMatch[i]->dump(); | |
| } | |
| #endif | |
| AllTypeChecks = false; | |
| } | |
| } | |
| } | |
| // If all the options are CheckOpcode's, we can form the SwitchOpcode, woot. | |
| if (AllOpcodeChecks) { | |
| StringSet<> Opcodes; | |
| SmallVector<std::pair<const SDNodeInfo*, Matcher*>, 8> Cases; | |
| for (unsigned i = 0, e = NewOptionsToMatch.size(); i != e; ++i) { | |
| CheckOpcodeMatcher *COM = cast<CheckOpcodeMatcher>(NewOptionsToMatch[i]); | |
| assert(Opcodes.insert(COM->getOpcode().getEnumName()).second && | |
| "Duplicate opcodes not factored?"); | |
| Cases.push_back(std::make_pair(&COM->getOpcode(), COM->takeNext())); | |
| delete COM; | |
| } | |
| MatcherPtr.reset(new SwitchOpcodeMatcher(Cases)); | |
| return; | |
| } | |
| // If all the options are CheckType's, we can form the SwitchType, woot. | |
| if (AllTypeChecks) { | |
| DenseMap<unsigned, unsigned> TypeEntry; | |
| SmallVector<std::pair<MVT::SimpleValueType, Matcher*>, 8> Cases; | |
| for (unsigned i = 0, e = NewOptionsToMatch.size(); i != e; ++i) { | |
| CheckTypeMatcher *CTM = | |
| cast_or_null<CheckTypeMatcher>(FindNodeWithKind(NewOptionsToMatch[i], | |
| Matcher::CheckType)); | |
| Matcher *MatcherWithoutCTM = NewOptionsToMatch[i]->unlinkNode(CTM); | |
| MVT::SimpleValueType CTMTy = CTM->getType(); | |
| delete CTM; | |
| unsigned &Entry = TypeEntry[CTMTy]; | |
| if (Entry != 0) { | |
| // If we have unfactored duplicate types, then we should factor them. | |
| Matcher *PrevMatcher = Cases[Entry-1].second; | |
| if (ScopeMatcher *SM = dyn_cast<ScopeMatcher>(PrevMatcher)) { | |
| SM->setNumChildren(SM->getNumChildren()+1); | |
| SM->resetChild(SM->getNumChildren()-1, MatcherWithoutCTM); | |
| continue; | |
| } | |
| Matcher *Entries[2] = { PrevMatcher, MatcherWithoutCTM }; | |
| Cases[Entry-1].second = new ScopeMatcher(Entries); | |
| continue; | |
| } | |
| Entry = Cases.size()+1; | |
| Cases.push_back(std::make_pair(CTMTy, MatcherWithoutCTM)); | |
| } | |
| // Make sure we recursively factor any scopes we may have created. | |
| for (auto &M : Cases) { | |
| if (ScopeMatcher *SM = dyn_cast<ScopeMatcher>(M.second)) { | |
| std::unique_ptr<Matcher> Scope(SM); | |
| FactorNodes(Scope); | |
| M.second = Scope.release(); | |
| assert(M.second && "null matcher"); | |
| } | |
| } | |
| if (Cases.size() != 1) { | |
| MatcherPtr.reset(new SwitchTypeMatcher(Cases)); | |
| } else { | |
| // If we factored and ended up with one case, create it now. | |
| MatcherPtr.reset(new CheckTypeMatcher(Cases[0].first, 0)); | |
| MatcherPtr->setNext(Cases[0].second); | |
| } | |
| return; | |
| } | |
| // Reassemble the Scope node with the adjusted children. | |
| Scope->setNumChildren(NewOptionsToMatch.size()); | |
| for (unsigned i = 0, e = NewOptionsToMatch.size(); i != e; ++i) | |
| Scope->resetChild(i, NewOptionsToMatch[i]); | |
| } | |
| void | |
| llvm::OptimizeMatcher(std::unique_ptr<Matcher> &MatcherPtr, | |
| const CodeGenDAGPatterns &CGP) { | |
| ContractNodes(MatcherPtr, CGP); | |
| FactorNodes(MatcherPtr); | |
| } |