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-rw-r--r--utils/TableGen/DAGISelMatcherOpt.cpp435
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diff --git a/utils/TableGen/DAGISelMatcherOpt.cpp b/utils/TableGen/DAGISelMatcherOpt.cpp
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+//===- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#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"
+#include <vector>
+using namespace llvm;
+
+/// ContractNodes - Turn multiple matcher node patterns like 'MoveChild+Record'
+/// into single compound nodes like RecordChild.
+static void ContractNodes(OwningPtr<Matcher> &MatcherPtr,
+ const CodeGenDAGPatterns &CGP) {
+ // If we reached the end of the chain, we're done.
+ Matcher *N = MatcherPtr.get();
+ if (N == 0) 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) {
+ OwningPtr<Matcher> Child(Scope->takeChild(i));
+ ContractNodes(Child, CGP);
+ Scope->resetChild(i, Child.take());
+ }
+ 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()))
+ New = new RecordChildMatcher(MC->getChildNo(), RM->getWhatFor(),
+ RM->getResultNo());
+
+ if (CheckTypeMatcher *CT= dyn_cast<CheckTypeMatcher>(MC->getNext()))
+ New = new CheckChildTypeMatcher(MC->getChildNo(), CT->getType());
+
+ if (New) {
+ // Insert the new node.
+ New->setNext(MatcherPtr.take());
+ 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<MarkFlagResultsMatcher>(N->getNext()) &&
+ isa<CompleteMatchMatcher>(N->getNext()->getNext())) {
+ // Unlink the two nodes from the list.
+ Matcher *EmitNode = MatcherPtr.take();
+ 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 flag/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 a flag and the output root doesn't, we can't
+ // use MorphNodeTo.
+ //
+ // NOTE: Strictly speaking, we don't have to check for the flag 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(SDNPOutFlag, CGP))
+ ResultsMatch = false;
+
+
+ // If the root result node defines more results than the source root node
+ // *and* has a chain or flag input, then we can't match it because it
+ // would end up replacing the extra result with the chain/flag.
+#if 0
+ if ((EN->hasFlag() || EN->hasChain()) &&
+ EN->getNumNonChainFlagVTs() > ... 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.data(), VTs.size(),
+ Operands.data(),Operands.size(),
+ 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.take();
+ 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(OwningPtr<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) {
+ OwningPtr<Matcher> Child(Scope->takeChild(i));
+ SinkPatternPredicates(Child);
+ Scope->resetChild(i, Child.take());
+ }
+ 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.take(); // 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);
+}
+
+/// FactorNodes - Turn matches like this:
+/// Scope
+/// OPC_CheckType i32
+/// ABC
+/// OPC_CheckType i32
+/// XYZ
+/// into:
+/// OPC_CheckType i32
+/// Scope
+/// ABC
+/// XYZ
+///
+static void FactorNodes(OwningPtr<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.
+ OwningPtr<Matcher> Child(Scope->takeChild(i));
+ FactorNodes(Child);
+
+ if (Matcher *N = Child.take())
+ 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) {
+ while (Scan != e && Optn->isContradictory(OptionsToMatch[Scan]))
+ ++Scan;
+
+ // Ok, we found something that isn't known to be contradictory. If it is
+ // equal, we can merge it into the set of nodes to factor, if not, we have
+ // to cease factoring.
+ if (Scan == e || !Optn->isEqual(OptionsToMatch[Scan])) break;
+
+ // If is equal after all, add the option to EqualMatchers and remove it
+ // from OptionsToMatch.
+ EqualMatchers.push_back(OptionsToMatch[Scan]);
+ OptionsToMatch.erase(OptionsToMatch.begin()+Scan);
+ --e;
+ }
+
+ 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[0], EqualMatchers.size()));
+
+ // 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) {
+ if (!isa<CheckOpcodeMatcher>(NewOptionsToMatch[i])) {
+#if 0
+ if (i > 3 && AllOpcodeChecks) {
+ errs() << "FAILING OPC #" << i << "\n";
+ NewOptionsToMatch[i]->dump();
+ }
+#endif
+ AllOpcodeChecks = false;
+ }
+
+ if (!isa<CheckTypeMatcher>(NewOptionsToMatch[i]) ||
+ // iPTR checks could alias any other case without us knowing, don't
+ // bother with them.
+ cast<CheckTypeMatcher>(NewOptionsToMatch[i])->getType() == MVT::iPTR) {
+#if 0
+ if (i > 3 && AllTypeChecks) {
+ errs() << "FAILING TYPE #" << i << "\n";
+ NewOptionsToMatch[i]->dump();
+ }
+#endif
+ AllTypeChecks = false;
+ }
+ }
+ // TODO: Can also do CheckChildNType.
+
+ // 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[0], Cases.size()));
+ return;
+ }
+
+ // If all the options are CheckType's, we can form the SwitchType, woot.
+ if (AllTypeChecks) {
+ DenseSet<unsigned> Types;
+ SmallVector<std::pair<MVT::SimpleValueType, Matcher*>, 8> Cases;
+ for (unsigned i = 0, e = NewOptionsToMatch.size(); i != e; ++i) {
+ CheckTypeMatcher *CTM = cast<CheckTypeMatcher>(NewOptionsToMatch[i]);
+ assert(Types.insert(CTM->getType()).second &&
+ "Duplicate types not factored?");
+ Cases.push_back(std::make_pair(CTM->getType(), CTM->getNext()));
+ }
+
+ MatcherPtr.reset(new SwitchTypeMatcher(&Cases[0], Cases.size()));
+ 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) {
+ OwningPtr<Matcher> MatcherPtr(TheMatcher);
+ ContractNodes(MatcherPtr, CGP);
+ SinkPatternPredicates(MatcherPtr);
+ FactorNodes(MatcherPtr);
+ return MatcherPtr.take();
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-06-22 12:43:23 +0000