//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "isel-opt"
#include "DAGISelMatcher.h"
+#include "CodeGenDAGPatterns.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/StringSet.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
using namespace llvm;
-
-static void FormRecordChildNodes(OwningPtr<MatcherNode> &Matcher) {
+/// 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.
- MatcherNode *N = Matcher.get();
+ Matcher *N = MatcherPtr.get();
if (N == 0) return;
- // If we have a push node, walk down both edges.
- if (PushMatcherNode *Push = dyn_cast<PushMatcherNode>(N))
- FormRecordChildNodes(Push->getFailurePtr());
-
- // If we found a movechild node, check to see if our pattern matches.
- if (MoveChildMatcherNode *MC = dyn_cast<MoveChildMatcherNode>(N)) {
- if (RecordMatcherNode *RM = dyn_cast<RecordMatcherNode>(MC->getNext()))
- if (MoveParentMatcherNode *MP =
- dyn_cast<MoveParentMatcherNode>(RM->getNext())) {
- MatcherNode *New
- = new RecordChildMatcherNode(MC->getChildNo(), RM->getWhatFor());
- New->setNext(MP->takeNext());
- Matcher.reset(New);
- return FormRecordChildNodes(Matcher);
+ // 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 = 0;
+ 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->MarkFlagResults->CompleteMatch into
+ // MarkFlagResults->EmitNode->CompleteMatch when we can to encourage
+ // MorphNodeTo formation. This is safe because MarkFlagResults never refers
+ // to the root of the pattern.
+ if (isa<EmitNodeMatcher>(N) && isa<MarkGlueResultsMatcher>(N->getNext()) &&
+ isa<CompleteMatchMatcher>(N->getNext()->getNext())) {
+ // Unlink the two nodes from the list.
+ Matcher *EmitNode = MatcherPtr.release();
+ Matcher *MFR = EmitNode->takeNext();
+ Matcher *Tail = MFR->takeNext();
+
+ // Relink them.
+ MatcherPtr.reset(MFR);
+ MFR->setNext(EmitNode);
+ EmitNode->setNext(Tail);
+ 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);
}
+}
+
+/// SinkPatternPredicates - Pattern predicates can be checked at any level of
+/// the matching tree. The generator dumps them at the top level of the pattern
+/// though, which prevents factoring from being able to see past them. This
+/// optimization sinks them as far down into the pattern as possible.
+///
+/// Conceptually, we'd like to sink these predicates all the way to the last
+/// matcher predicate in the series. However, it turns out that some
+/// ComplexPatterns have side effects on the graph, so we really don't want to
+/// run a the complex pattern if the pattern predicate will fail. For this
+/// reason, we refuse to sink the pattern predicate past a ComplexPattern.
+///
+static void SinkPatternPredicates(std::unique_ptr<Matcher> &MatcherPtr) {
+ // Recursively scan for a PatternPredicate.
+ // If we reached the end of the chain, we're done.
+ Matcher *N = MatcherPtr.get();
+ if (N == 0) return;
+
+ // Walk down all members of a scope node.
+ 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));
+ SinkPatternPredicates(Child);
+ Scope->resetChild(i, Child.release());
+ }
+ return;
+ }
+
+ // If this node isn't a CheckPatternPredicateMatcher we keep scanning until
+ // we find one.
+ CheckPatternPredicateMatcher *CPPM =dyn_cast<CheckPatternPredicateMatcher>(N);
+ if (CPPM == 0)
+ return SinkPatternPredicates(N->getNextPtr());
+
+ // Ok, we found one, lets try to sink it. Check if we can sink it past the
+ // next node in the chain. If not, we won't be able to change anything and
+ // might as well bail.
+ if (!CPPM->getNext()->isSafeToReorderWithPatternPredicate())
+ return;
+
+ // Okay, we know we can sink it past at least one node. Unlink it from the
+ // chain and scan for the new insertion point.
+ MatcherPtr.release(); // Don't delete CPPM.
+ MatcherPtr.reset(CPPM->takeNext());
+
+ N = MatcherPtr.get();
+ while (N->getNext()->isSafeToReorderWithPatternPredicate())
+ N = N->getNext();
+
+ // At this point, we want to insert CPPM after N.
+ CPPM->setNext(N->takeNext());
+ N->setNext(CPPM);
+}
- FormRecordChildNodes(N->getNextPtr());
+/// 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 0;
}
-MatcherNode *llvm::OptimizeMatcher(MatcherNode *Matcher) {
- OwningPtr<MatcherNode> MatcherPtr(Matcher);
- FormRecordChildNodes(MatcherPtr);
- return MatcherPtr.take();
+/// 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> &MatcherPtr) {
+ // If we reached the end of the chain, we're done.
+ Matcher *N = MatcherPtr.get();
+ if (N == 0) return;
+
+ // If this is not a push node, just scan for one.
+ ScopeMatcher *Scope = dyn_cast<ScopeMatcher>(N);
+ if (Scope == 0)
+ return FactorNodes(N->getNextPtr());
+
+ // Okay, pull together the children of the scope node into a vector so we can
+ // inspect it more easily. While we're at it, bucket them up by the hash
+ // code of their first predicate.
+ 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 (Matcher *N = Child.release())
+ OptionsToMatch.push_back(N);
+ }
+
+ 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 != 0 && 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) {
+ 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(0);
+ 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 == 0 ||
+ // 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()) &&
+ "Duplicate opcodes not factored?");
+ Cases.push_back(std::make_pair(&COM->getOpcode(), COM->getNext()));
+ }
+
+ 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));
+ }
+
+ 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]);
+}
+
+Matcher *llvm::OptimizeMatcher(Matcher *TheMatcher,
+ const CodeGenDAGPatterns &CGP) {
+ std::unique_ptr<Matcher> MatcherPtr(TheMatcher);
+ ContractNodes(MatcherPtr, CGP);
+ SinkPatternPredicates(MatcherPtr);
+ FactorNodes(MatcherPtr);
+ return MatcherPtr.release();
}
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