[NFC][TableGen][GlobalISel] Move MIR pattern parsing out of combiner (#86789)

Reland of cfa0833ccc7450a322e709583e894e4c96ce682e

6 files changed, 623 insertions, 465 deletions

diff --git a/llvm/utils/TableGen/Common/CMakeLists.txt b/llvm/utils/TableGen/Common/CMakeLists.txt
index 0440f02..c31ed5a 100644
--- a/llvm/utils/TableGen/Common/CMakeLists.txt
+++ b/llvm/utils/TableGen/Common/CMakeLists.txt
@@ -12,10 +12,12 @@ set(LLVM_LINK_COMPONENTS
 
 add_llvm_library(LLVMTableGenCommon STATIC OBJECT EXCLUDE_FROM_ALL
   GlobalISel/CodeExpander.cpp
+  GlobalISel/CombinerUtils.cpp
   GlobalISel/CXXPredicates.cpp
   GlobalISel/GlobalISelMatchTable.cpp
   GlobalISel/GlobalISelMatchTableExecutorEmitter.cpp
   GlobalISel/MatchDataInfo.cpp
+  GlobalISel/PatternParser.cpp
   GlobalISel/Patterns.cpp
 
   AsmWriterInst.cpp
diff --git a/llvm/utils/TableGen/Common/GlobalISel/CombinerUtils.cpp b/llvm/utils/TableGen/Common/GlobalISel/CombinerUtils.cpp
new file mode 100644
index 0000000..37e6306
--- /dev/null
+++ b/llvm/utils/TableGen/Common/GlobalISel/CombinerUtils.cpp
@@ -0,0 +1,23 @@
+//===- CombinerUtils.cpp --------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "CombinerUtils.h"
+#include "llvm/ADT/StringSet.h"
+
+namespace llvm {
+
+StringRef insertStrRef(StringRef S) {
+  if (S.empty())
+    return {};
+
+  static StringSet<> Pool;
+  auto [It, Inserted] = Pool.insert(S);
+  return It->getKey();
+}
+
+} // namespace llvm
diff --git a/llvm/utils/TableGen/Common/GlobalISel/CombinerUtils.h b/llvm/utils/TableGen/Common/GlobalISel/CombinerUtils.h
index 8cb2514..82a64c6 100644
--- a/llvm/utils/TableGen/Common/GlobalISel/CombinerUtils.h
+++ b/llvm/utils/TableGen/Common/GlobalISel/CombinerUtils.h
@@ -65,6 +65,10 @@ inline const DagInit *getDagWithOperatorOfSubClass(const Init &N,
         return I;
   return nullptr;
 }
+
+/// Copies a StringRef into a static pool to preserve it.
+StringRef insertStrRef(StringRef S);
+
 } // namespace llvm
 
 #endif
diff --git a/llvm/utils/TableGen/Common/GlobalISel/PatternParser.cpp b/llvm/utils/TableGen/Common/GlobalISel/PatternParser.cpp
new file mode 100644
index 0000000..1d6c4c7
--- /dev/null
+++ b/llvm/utils/TableGen/Common/GlobalISel/PatternParser.cpp
@@ -0,0 +1,462 @@
+//===- PatternParser.cpp ----------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Common/GlobalISel/PatternParser.h"
+#include "Basic/CodeGenIntrinsics.h"
+#include "Common/CodeGenTarget.h"
+#include "Common/GlobalISel/CombinerUtils.h"
+#include "Common/GlobalISel/Patterns.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/SaveAndRestore.h"
+#include "llvm/TableGen/Error.h"
+#include "llvm/TableGen/Record.h"
+
+namespace llvm {
+namespace gi {
+static constexpr StringLiteral MIFlagsEnumClassName = "MIFlagEnum";
+
+namespace {
+class PrettyStackTraceParse : public PrettyStackTraceEntry {
+  const Record &Def;
+
+public:
+  PrettyStackTraceParse(const Record &Def) : Def(Def) {}
+
+  void print(raw_ostream &OS) const override {
+    if (Def.isSubClassOf("GICombineRule"))
+      OS << "Parsing GICombineRule '" << Def.getName() << '\'';
+    else if (Def.isSubClassOf(PatFrag::ClassName))
+      OS << "Parsing " << PatFrag::ClassName << " '" << Def.getName() << '\'';
+    else
+      OS << "Parsing '" << Def.getName() << '\'';
+    OS << '\n';
+  }
+};
+} // namespace
+
+bool PatternParser::parsePatternList(
+    const DagInit &List,
+    function_ref<bool(std::unique_ptr<Pattern>)> ParseAction,
+    StringRef Operator, StringRef AnonPatNamePrefix) {
+  if (List.getOperatorAsDef(DiagLoc)->getName() != Operator) {
+    PrintError(DiagLoc, "Expected " + Operator + " operator");
+    return false;
+  }
+
+  if (List.getNumArgs() == 0) {
+    PrintError(DiagLoc, Operator + " pattern list is empty");
+    return false;
+  }
+
+  // The match section consists of a list of matchers and predicates. Parse each
+  // one and add the equivalent GIMatchDag nodes, predicates, and edges.
+  for (unsigned I = 0; I < List.getNumArgs(); ++I) {
+    Init *Arg = List.getArg(I);
+    std::string Name = List.getArgName(I)
+                           ? List.getArgName(I)->getValue().str()
+                           : ("__" + AnonPatNamePrefix + "_" + Twine(I)).str();
+
+    if (auto Pat = parseInstructionPattern(*Arg, Name)) {
+      if (!ParseAction(std::move(Pat)))
+        return false;
+      continue;
+    }
+
+    if (auto Pat = parseWipMatchOpcodeMatcher(*Arg, Name)) {
+      if (!ParseAction(std::move(Pat)))
+        return false;
+      continue;
+    }
+
+    // Parse arbitrary C++ code
+    if (const auto *StringI = dyn_cast<StringInit>(Arg)) {
+      auto CXXPat = std::make_unique<CXXPattern>(*StringI, insertStrRef(Name));
+      if (!ParseAction(std::move(CXXPat)))
+        return false;
+      continue;
+    }
+
+    PrintError(DiagLoc,
+               "Failed to parse pattern: '" + Arg->getAsString() + '\'');
+    return false;
+  }
+
+  return true;
+}
+
+static const CodeGenInstruction &
+getInstrForIntrinsic(const CodeGenTarget &CGT, const CodeGenIntrinsic *I) {
+  StringRef Opc;
+  if (I->isConvergent) {
+    Opc = I->hasSideEffects ? "G_INTRINSIC_CONVERGENT_W_SIDE_EFFECTS"
+                            : "G_INTRINSIC_CONVERGENT";
+  } else {
+    Opc = I->hasSideEffects ? "G_INTRINSIC_W_SIDE_EFFECTS" : "G_INTRINSIC";
+  }
+
+  RecordKeeper &RK = I->TheDef->getRecords();
+  return CGT.getInstruction(RK.getDef(Opc));
+}
+
+static const CodeGenIntrinsic *getCodeGenIntrinsic(Record *R) {
+  // Intrinsics need to have a static lifetime because the match table keeps
+  // references to CodeGenIntrinsic objects.
+  static DenseMap<const Record *, std::unique_ptr<CodeGenIntrinsic>>
+      AllIntrinsics;
+
+  auto &Ptr = AllIntrinsics[R];
+  if (!Ptr)
+    Ptr = std::make_unique<CodeGenIntrinsic>(R, std::vector<Record *>());
+  return Ptr.get();
+}
+
+std::unique_ptr<Pattern>
+PatternParser::parseInstructionPattern(const Init &Arg, StringRef Name) {
+  const DagInit *DagPat = dyn_cast<DagInit>(&Arg);
+  if (!DagPat)
+    return nullptr;
+
+  std::unique_ptr<InstructionPattern> Pat;
+  if (const DagInit *IP = getDagWithOperatorOfSubClass(Arg, "Instruction")) {
+    auto &Instr = CGT.getInstruction(IP->getOperatorAsDef(DiagLoc));
+    Pat =
+        std::make_unique<CodeGenInstructionPattern>(Instr, insertStrRef(Name));
+  } else if (const DagInit *IP =
+                 getDagWithOperatorOfSubClass(Arg, "Intrinsic")) {
+    Record *TheDef = IP->getOperatorAsDef(DiagLoc);
+    const CodeGenIntrinsic *Intrin = getCodeGenIntrinsic(TheDef);
+    const CodeGenInstruction &Instr = getInstrForIntrinsic(CGT, Intrin);
+    Pat =
+        std::make_unique<CodeGenInstructionPattern>(Instr, insertStrRef(Name));
+    cast<CodeGenInstructionPattern>(*Pat).setIntrinsic(Intrin);
+  } else if (const DagInit *PFP =
+                 getDagWithOperatorOfSubClass(Arg, PatFrag::ClassName)) {
+    const Record *Def = PFP->getOperatorAsDef(DiagLoc);
+    const PatFrag *PF = parsePatFrag(Def);
+    if (!PF)
+      return nullptr; // Already diagnosed by parsePatFrag
+    Pat = std::make_unique<PatFragPattern>(*PF, insertStrRef(Name));
+  } else if (const DagInit *BP =
+                 getDagWithOperatorOfSubClass(Arg, BuiltinPattern::ClassName)) {
+    Pat = std::make_unique<BuiltinPattern>(*BP->getOperatorAsDef(DiagLoc),
+                                           insertStrRef(Name));
+  } else
+    return nullptr;
+
+  for (unsigned K = 0; K < DagPat->getNumArgs(); ++K) {
+    Init *Arg = DagPat->getArg(K);
+    if (auto *DagArg = getDagWithSpecificOperator(*Arg, "MIFlags")) {
+      if (!parseInstructionPatternMIFlags(*Pat, DagArg))
+        return nullptr;
+      continue;
+    }
+
+    if (!parseInstructionPatternOperand(*Pat, Arg, DagPat->getArgName(K)))
+      return nullptr;
+  }
+
+  if (!Pat->checkSemantics(DiagLoc))
+    return nullptr;
+
+  return std::move(Pat);
+}
+
+std::unique_ptr<Pattern>
+PatternParser::parseWipMatchOpcodeMatcher(const Init &Arg, StringRef Name) {
+  const DagInit *Matcher = getDagWithSpecificOperator(Arg, "wip_match_opcode");
+  if (!Matcher)
+    return nullptr;
+
+  if (Matcher->getNumArgs() == 0) {
+    PrintError(DiagLoc, "Empty wip_match_opcode");
+    return nullptr;
+  }
+
+  // Each argument is an opcode that can match.
+  auto Result = std::make_unique<AnyOpcodePattern>(insertStrRef(Name));
+  for (const auto &Arg : Matcher->getArgs()) {
+    Record *OpcodeDef = getDefOfSubClass(*Arg, "Instruction");
+    if (OpcodeDef) {
+      Result->addOpcode(&CGT.getInstruction(OpcodeDef));
+      continue;
+    }
+
+    PrintError(DiagLoc, "Arguments to wip_match_opcode must be instructions");
+    return nullptr;
+  }
+
+  return std::move(Result);
+}
+
+bool PatternParser::parseInstructionPatternOperand(InstructionPattern &IP,
+                                                   const Init *OpInit,
+                                                   const StringInit *OpName) {
+  const auto ParseErr = [&]() {
+    PrintError(DiagLoc,
+               "cannot parse operand '" + OpInit->getAsUnquotedString() + "' ");
+    if (OpName)
+      PrintNote(DiagLoc,
+                "operand name is '" + OpName->getAsUnquotedString() + '\'');
+    return false;
+  };
+
+  // untyped immediate, e.g. 0
+  if (const auto *IntImm = dyn_cast<IntInit>(OpInit)) {
+    std::string Name = OpName ? OpName->getAsUnquotedString() : "";
+    IP.addOperand(IntImm->getValue(), insertStrRef(Name), PatternType());
+    return true;
+  }
+
+  // typed immediate, e.g. (i32 0)
+  if (const auto *DagOp = dyn_cast<DagInit>(OpInit)) {
+    if (DagOp->getNumArgs() != 1)
+      return ParseErr();
+
+    const Record *TyDef = DagOp->getOperatorAsDef(DiagLoc);
+    auto ImmTy = PatternType::get(DiagLoc, TyDef,
+                                  "cannot parse immediate '" +
+                                      DagOp->getAsUnquotedString() + '\'');
+    if (!ImmTy)
+      return false;
+
+    if (!IP.hasAllDefs()) {
+      PrintError(DiagLoc, "out operand of '" + IP.getInstName() +
+                              "' cannot be an immediate");
+      return false;
+    }
+
+    const auto *Val = dyn_cast<IntInit>(DagOp->getArg(0));
+    if (!Val)
+      return ParseErr();
+
+    std::string Name = OpName ? OpName->getAsUnquotedString() : "";
+    IP.addOperand(Val->getValue(), insertStrRef(Name), *ImmTy);
+    return true;
+  }
+
+  // Typed operand e.g. $x/$z in (G_FNEG $x, $z)
+  if (auto *DefI = dyn_cast<DefInit>(OpInit)) {
+    if (!OpName) {
+      PrintError(DiagLoc, "expected an operand name after '" +
+                              OpInit->getAsString() + '\'');
+      return false;
+    }
+    const Record *Def = DefI->getDef();
+    auto Ty = PatternType::get(DiagLoc, Def, "cannot parse operand type");
+    if (!Ty)
+      return false;
+    IP.addOperand(insertStrRef(OpName->getAsUnquotedString()), *Ty);
+    return true;
+  }
+
+  // Untyped operand e.g. $x/$z in (G_FNEG $x, $z)
+  if (isa<UnsetInit>(OpInit)) {
+    assert(OpName && "Unset w/ no OpName?");
+    IP.addOperand(insertStrRef(OpName->getAsUnquotedString()), PatternType());
+    return true;
+  }
+
+  return ParseErr();
+}
+
+bool PatternParser::parseInstructionPatternMIFlags(InstructionPattern &IP,
+                                                   const DagInit *Op) {
+  auto *CGIP = dyn_cast<CodeGenInstructionPattern>(&IP);
+  if (!CGIP) {
+    PrintError(DiagLoc,
+               "matching/writing MIFlags is only allowed on CodeGenInstruction "
+               "patterns");
+    return false;
+  }
+
+  const auto CheckFlagEnum = [&](const Record *R) {
+    if (!R->isSubClassOf(MIFlagsEnumClassName)) {
+      PrintError(DiagLoc, "'" + R->getName() + "' is not a subclass of '" +
+                              MIFlagsEnumClassName + "'");
+      return false;
+    }
+
+    return true;
+  };
+
+  if (CGIP->getMIFlagsInfo()) {
+    PrintError(DiagLoc, "MIFlags can only be present once on an instruction");
+    return false;
+  }
+
+  auto &FI = CGIP->getOrCreateMIFlagsInfo();
+  for (unsigned K = 0; K < Op->getNumArgs(); ++K) {
+    const Init *Arg = Op->getArg(K);
+
+    // Match/set a flag: (MIFlags FmNoNans)
+    if (const auto *Def = dyn_cast<DefInit>(Arg)) {
+      const Record *R = Def->getDef();
+      if (!CheckFlagEnum(R))
+        return false;
+
+      FI.addSetFlag(R);
+      continue;
+    }
+
+    // Do not match a flag/unset a flag: (MIFlags (not FmNoNans))
+    if (const DagInit *NotDag = getDagWithSpecificOperator(*Arg, "not")) {
+      for (const Init *NotArg : NotDag->getArgs()) {
+        const DefInit *DefArg = dyn_cast<DefInit>(NotArg);
+        if (!DefArg) {
+          PrintError(DiagLoc, "cannot parse '" + NotArg->getAsUnquotedString() +
+                                  "': expected a '" + MIFlagsEnumClassName +
+                                  "'");
+          return false;
+        }
+
+        const Record *R = DefArg->getDef();
+        if (!CheckFlagEnum(R))
+          return false;
+
+        FI.addUnsetFlag(R);
+        continue;
+      }
+
+      continue;
+    }
+
+    // Copy flags from a matched instruction: (MIFlags $mi)
+    if (isa<UnsetInit>(Arg)) {
+      FI.addCopyFlag(insertStrRef(Op->getArgName(K)->getAsUnquotedString()));
+      continue;
+    }
+  }
+
+  return true;
+}
+
+std::unique_ptr<PatFrag> PatternParser::parsePatFragImpl(const Record *Def) {
+  auto StackTrace = PrettyStackTraceParse(*Def);
+  if (!Def->isSubClassOf(PatFrag::ClassName))
+    return nullptr;
+
+  const DagInit *Ins = Def->getValueAsDag("InOperands");
+  if (Ins->getOperatorAsDef(Def->getLoc())->getName() != "ins") {
+    PrintError(Def, "expected 'ins' operator for " + PatFrag::ClassName +
+                        " in operands list");
+    return nullptr;
+  }
+
+  const DagInit *Outs = Def->getValueAsDag("OutOperands");
+  if (Outs->getOperatorAsDef(Def->getLoc())->getName() != "outs") {
+    PrintError(Def, "expected 'outs' operator for " + PatFrag::ClassName +
+                        " out operands list");
+    return nullptr;
+  }
+
+  auto Result = std::make_unique<PatFrag>(*Def);
+  if (!parsePatFragParamList(*Outs, [&](StringRef Name, unsigned Kind) {
+        Result->addOutParam(insertStrRef(Name), (PatFrag::ParamKind)Kind);
+        return true;
+      }))
+    return nullptr;
+
+  if (!parsePatFragParamList(*Ins, [&](StringRef Name, unsigned Kind) {
+        Result->addInParam(insertStrRef(Name), (PatFrag::ParamKind)Kind);
+        return true;
+      }))
+    return nullptr;
+
+  const ListInit *Alts = Def->getValueAsListInit("Alternatives");
+  unsigned AltIdx = 0;
+  for (const Init *Alt : *Alts) {
+    const auto *PatDag = dyn_cast<DagInit>(Alt);
+    if (!PatDag) {
+      PrintError(Def, "expected dag init for PatFrag pattern alternative");
+      return nullptr;
+    }
+
+    PatFrag::Alternative &A = Result->addAlternative();
+    const auto AddPat = [&](std::unique_ptr<Pattern> Pat) {
+      A.Pats.push_back(std::move(Pat));
+      return true;
+    };
+
+    SaveAndRestore<ArrayRef<SMLoc>> DiagLocSAR(DiagLoc, Def->getLoc());
+    if (!parsePatternList(
+            *PatDag, AddPat, "pattern",
+            /*AnonPatPrefix*/
+            (Def->getName() + "_alt" + Twine(AltIdx++) + "_pattern").str()))
+      return nullptr;
+  }
+
+  if (!Result->buildOperandsTables() || !Result->checkSemantics())
+    return nullptr;
+
+  return Result;
+}
+
+bool PatternParser::parsePatFragParamList(
+    const DagInit &OpsList,
+    function_ref<bool(StringRef, unsigned)> ParseAction) {
+  for (unsigned K = 0; K < OpsList.getNumArgs(); ++K) {
+    const StringInit *Name = OpsList.getArgName(K);
+    const Init *Ty = OpsList.getArg(K);
+
+    if (!Name) {
+      PrintError(DiagLoc, "all operands must be named'");
+      return false;
+    }
+    const std::string NameStr = Name->getAsUnquotedString();
+
+    PatFrag::ParamKind OpKind;
+    if (isSpecificDef(*Ty, "gi_imm"))
+      OpKind = PatFrag::PK_Imm;
+    else if (isSpecificDef(*Ty, "root"))
+      OpKind = PatFrag::PK_Root;
+    else if (isa<UnsetInit>(Ty) ||
+             isSpecificDef(*Ty, "gi_mo")) // no type = gi_mo.
+      OpKind = PatFrag::PK_MachineOperand;
+    else {
+      PrintError(
+          DiagLoc,
+          '\'' + NameStr +
+              "' operand type was expected to be 'root', 'gi_imm' or 'gi_mo'");
+      return false;
+    }
+
+    if (!ParseAction(NameStr, (unsigned)OpKind))
+      return false;
+  }
+
+  return true;
+}
+
+const PatFrag *PatternParser::parsePatFrag(const Record *Def) {
+  // Cache already parsed PatFrags to avoid doing extra work.
+  static DenseMap<const Record *, std::unique_ptr<PatFrag>> ParsedPatFrags;
+
+  auto It = ParsedPatFrags.find(Def);
+  if (It != ParsedPatFrags.end()) {
+    SeenPatFrags.insert(It->second.get());
+    return It->second.get();
+  }
+
+  std::unique_ptr<PatFrag> NewPatFrag = parsePatFragImpl(Def);
+  if (!NewPatFrag) {
+    PrintError(Def, "Could not parse " + PatFrag::ClassName + " '" +
+                        Def->getName() + "'");
+    // Put a nullptr in the map so we don't attempt parsing this again.
+    ParsedPatFrags[Def] = nullptr;
+    return nullptr;
+  }
+
+  const auto *Res = NewPatFrag.get();
+  ParsedPatFrags[Def] = std::move(NewPatFrag);
+  SeenPatFrags.insert(Res);
+  return Res;
+}
+
+} // namespace gi
+} // namespace llvm
diff --git a/llvm/utils/TableGen/Common/GlobalISel/PatternParser.h b/llvm/utils/TableGen/Common/GlobalISel/PatternParser.h
new file mode 100644
index 0000000..cd6f524
--- /dev/null
+++ b/llvm/utils/TableGen/Common/GlobalISel/PatternParser.h
@@ -0,0 +1,118 @@
+//===- PatternParser.h ------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file Contains tools to parse MIR patterns from TableGen DAG elements.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_UTILS_GLOBALISEL_PATTERNPARSER_H
+#define LLVM_UTILS_GLOBALISEL_PATTERNPARSER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLFunctionalExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/SMLoc.h"
+#include <memory>
+
+namespace llvm {
+class CodeGenTarget;
+class DagInit;
+class Init;
+class Record;
+class StringRef;
+class StringInit;
+
+namespace gi {
+class InstructionPattern;
+class Pattern;
+class PatFrag;
+
+/// Helper class to parse MIR Pattern lists.
+///
+/// e.g., `(match (G_FADD $x, $y, $z), (G_FNEG $y, $z))`
+class PatternParser {
+  const CodeGenTarget &CGT;
+  ArrayRef<SMLoc> DiagLoc;
+
+  mutable SmallPtrSet<const PatFrag *, 2> SeenPatFrags;
+
+public:
+  PatternParser(const CodeGenTarget &CGT, ArrayRef<SMLoc> DiagLoc)
+      : CGT(CGT), DiagLoc(DiagLoc) {}
+
+  /// Parses a list of patterns such as:
+  ///   (Operator (Pattern1 ...), (Pattern2 ...))
+  /// \param List         DagInit of the expected pattern list.
+  /// \param ParseAction  Callback to handle a succesfully parsed pattern.
+  /// \param Operator     The name of the operator, e.g. "match"
+  /// \param AnonPatNamePrefix Prefix for anonymous pattern names.
+  /// \return true on success, false on failure.
+  bool
+  parsePatternList(const DagInit &List,
+                   function_ref<bool(std::unique_ptr<Pattern>)> ParseAction,
+                   StringRef Operator, StringRef AnonPatNamePrefix);
+
+  /// \returns all PatFrags encountered by this PatternParser.
+  const auto &getSeenPatFrags() const { return SeenPatFrags; }
+
+private:
+  /// Parse any InstructionPattern from a TableGen Init.
+  /// \param Arg Init to parse.
+  /// \param PatName Name of the pattern that will be parsed.
+  /// \return the parsed pattern on success, nullptr on failure.
+  std::unique_ptr<Pattern> parseInstructionPattern(const Init &Arg,
+                                                   StringRef PatName);
+
+  /// Parse a WipOpcodeMatcher from a TableGen Init.
+  /// \param Arg Init to parse.
+  /// \param PatName Name of the pattern that will be parsed.
+  /// \return the parsed pattern on success, nullptr on failure.
+  std::unique_ptr<Pattern> parseWipMatchOpcodeMatcher(const Init &Arg,
+                                                      StringRef PatName);
+
+  /// Parses an Operand of an InstructionPattern from a TableGen Init.
+  /// \param IP InstructionPattern for which we're parsing.
+  /// \param OpInit Init to parse.
+  /// \param OpName Name of the operand to parse.
+  /// \return true on success, false on failure.
+  bool parseInstructionPatternOperand(InstructionPattern &IP,
+                                      const Init *OpInit,
+                                      const StringInit *OpName);
+
+  /// Parses a MIFlag for an InstructionPattern from a TableGen Init.
+  /// \param IP InstructionPattern for which we're parsing.
+  /// \param Op Init to parse.
+  /// \return true on success, false on failure.
+  bool parseInstructionPatternMIFlags(InstructionPattern &IP,
+                                      const DagInit *Op);
+
+  /// (Uncached) PatFrag parsing implementation.
+  /// \param Def PatFrag def to parsee.
+  /// \return the parsed PatFrag on success, nullptr on failure.
+  std::unique_ptr<PatFrag> parsePatFragImpl(const Record *Def);
+
+  /// Parses the in or out parameter list of a PatFrag.
+  /// \param OpsList Init to parse.
+  /// \param ParseAction Callback on successful parse, with the name of
+  ///                     the parameter and its \ref PatFrag::ParamKind
+  /// \return true on success, false on failure.
+  bool
+  parsePatFragParamList(const DagInit &OpsList,
+                        function_ref<bool(StringRef, unsigned)> ParseAction);
+
+  /// Cached PatFrag parser. This avoids duplicate work by keeping track of
+  /// already-parsed PatFrags.
+  /// \param Def PatFrag def to parsee.
+  /// \return the parsed PatFrag on success, nullptr on failure.
+  const PatFrag *parsePatFrag(const Record *Def);
+};
+
+} // namespace gi
+} // namespace llvm
+
+#endif
diff --git a/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp b/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp
index 39b9f8a..1ae6efd 100644
--- a/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp
@@ -36,6 +36,7 @@
 #include "Common/GlobalISel/GlobalISelMatchTable.h"
 #include "Common/GlobalISel/GlobalISelMatchTableExecutorEmitter.h"
 #include "Common/GlobalISel/MatchDataInfo.h"
+#include "Common/GlobalISel/PatternParser.h"
 #include "Common/GlobalISel/Patterns.h"
 #include "Common/SubtargetFeatureInfo.h"
 #include "llvm/ADT/APInt.h"
@@ -80,7 +81,6 @@ cl::opt<bool> DebugTypeInfer("gicombiner-debug-typeinfer",
 
 constexpr StringLiteral CXXApplyPrefix = "GICXXCustomAction_CombineApply";
 constexpr StringLiteral CXXPredPrefix = "GICXXPred_MI_Predicate_";
-constexpr StringLiteral MIFlagsEnumClassName = "MIFlagEnum";
 
 //===- CodeExpansions Helpers  --------------------------------------------===//
 
@@ -109,17 +109,6 @@ void declareTempRegExpansion(CodeExpansions &CE, unsigned TempRegID,
 
 //===- Misc. Helpers  -----------------------------------------------------===//
 
-/// Copies a StringRef into a static pool to preserve it.
-/// Most Pattern classes use StringRef so we need this.
-StringRef insertStrRef(StringRef S) {
-  if (S.empty())
-    return {};
-
-  static StringSet<> Pool;
-  auto [It, Inserted] = Pool.insert(S);
-  return It->getKey();
-}
-
 template <typename Container> auto keys(Container &&C) {
   return map_range(C, [](auto &Entry) -> auto & { return Entry.first; });
 }
@@ -639,8 +628,9 @@ public:
                      SubtargetFeatureInfoMap &SubtargetFeatures,
                      Record &RuleDef, unsigned ID,
                      std::vector<RuleMatcher> &OutRMs)
-      : CGT(CGT), SubtargetFeatures(SubtargetFeatures), RuleDef(RuleDef),
-        RuleID(ID), OutRMs(OutRMs) {}
+      : Parser(CGT, RuleDef.getLoc()), CGT(CGT),
+        SubtargetFeatures(SubtargetFeatures), RuleDef(RuleDef), RuleID(ID),
+        OutRMs(OutRMs) {}
 
   /// Parses all fields in the RuleDef record.
   bool parseAll();
@@ -718,26 +708,6 @@ private:
   bool buildRuleOperandsTable();
 
   bool parseDefs(const DagInit &Def);
-  bool
-  parsePatternList(const DagInit &List,
-                   function_ref<bool(std::unique_ptr<Pattern>)> ParseAction,
-                   StringRef Operator, ArrayRef<SMLoc> DiagLoc,
-                   StringRef AnonPatNamePrefix) const;
-
-  std::unique_ptr<Pattern> parseInstructionPattern(const Init &Arg,
-                                                   StringRef PatName) const;
-  std::unique_ptr<Pattern> parseWipMatchOpcodeMatcher(const Init &Arg,
-                                                      StringRef PatName) const;
-  bool parseInstructionPatternOperand(InstructionPattern &IP,
-                                      const Init *OpInit,
-                                      const StringInit *OpName) const;
-  bool parseInstructionPatternMIFlags(InstructionPattern &IP,
-                                      const DagInit *Op) const;
-  std::unique_ptr<PatFrag> parsePatFragImpl(const Record *Def) const;
-  bool parsePatFragParamList(
-      ArrayRef<SMLoc> DiagLoc, const DagInit &OpsList,
-      function_ref<bool(StringRef, PatFrag::ParamKind)> ParseAction) const;
-  const PatFrag *parsePatFrag(const Record *Def) const;
 
   bool emitMatchPattern(CodeExpansions &CE, const PatternAlternatives &Alts,
                         const InstructionPattern &IP);
@@ -781,6 +751,7 @@ private:
       DenseSet<const Pattern *> &SeenPats, OperandDefLookupFn LookupOperandDef,
       OperandMapperFnRef OperandMapper = [](const auto &O) { return O; });
 
+  PatternParser Parser;
   const CodeGenTarget &CGT;
   SubtargetFeatureInfoMap &SubtargetFeatures;
   Record &RuleDef;
@@ -808,9 +779,6 @@ private:
 
   SmallVector<MatchDataInfo, 2> MatchDatas;
   SmallVector<PatternAlternatives, 1> PermutationsToEmit;
-
-  // print()/debug-only members.
-  mutable SmallPtrSet<const PatFrag *, 2> SeenPatFrags;
 };
 
 bool CombineRuleBuilder::parseAll() {
@@ -819,16 +787,16 @@ bool CombineRuleBuilder::parseAll() {
   if (!parseDefs(*RuleDef.getValueAsDag("Defs")))
     return false;
 
-  if (!parsePatternList(
+  if (!Parser.parsePatternList(
           *RuleDef.getValueAsDag("Match"),
           [this](auto Pat) { return addMatchPattern(std::move(Pat)); }, "match",
-          RuleDef.getLoc(), (RuleDef.getName() + "_match").str()))
+          (RuleDef.getName() + "_match").str()))
     return false;
 
-  if (!parsePatternList(
+  if (!Parser.parsePatternList(
           *RuleDef.getValueAsDag("Apply"),
           [this](auto Pat) { return addApplyPattern(std::move(Pat)); }, "apply",
-          RuleDef.getLoc(), (RuleDef.getName() + "_apply").str()))
+          (RuleDef.getName() + "_apply").str()))
     return false;
 
   if (!buildRuleOperandsTable() || !typecheckPatterns() || !findRoots() ||
@@ -884,9 +852,10 @@ void CombineRuleBuilder::print(raw_ostream &OS) const {
     OS << "  )\n";
   }
 
-  if (!SeenPatFrags.empty()) {
+  const auto &SeenPFs = Parser.getSeenPatFrags();
+  if (!SeenPFs.empty()) {
     OS << "  (PatFrags\n";
-    for (const auto *PF : SeenPatFrags) {
+    for (const auto *PF : Parser.getSeenPatFrags()) {
       PF->print(OS, /*Indent=*/"    ");
       OS << '\n';
     }
@@ -1500,426 +1469,6 @@ bool CombineRuleBuilder::parseDefs(const DagInit &Def) {
   return true;
 }
 
-bool CombineRuleBuilder::parsePatternList(
-    const DagInit &List,
-    function_ref<bool(std::unique_ptr<Pattern>)> ParseAction,
-    StringRef Operator, ArrayRef<SMLoc> DiagLoc,
-    StringRef AnonPatNamePrefix) const {
-  if (List.getOperatorAsDef(RuleDef.getLoc())->getName() != Operator) {
-    ::PrintError(DiagLoc, "Expected " + Operator + " operator");
-    return false;
-  }
-
-  if (List.getNumArgs() == 0) {
-    ::PrintError(DiagLoc, Operator + " pattern list is empty");
-    return false;
-  }
-
-  // The match section consists of a list of matchers and predicates. Parse each
-  // one and add the equivalent GIMatchDag nodes, predicates, and edges.
-  for (unsigned I = 0; I < List.getNumArgs(); ++I) {
-    Init *Arg = List.getArg(I);
-    std::string Name = List.getArgName(I)
-                           ? List.getArgName(I)->getValue().str()
-                           : ("__" + AnonPatNamePrefix + "_" + Twine(I)).str();
-
-    if (auto Pat = parseInstructionPattern(*Arg, Name)) {
-      if (!ParseAction(std::move(Pat)))
-        return false;
-      continue;
-    }
-
-    if (auto Pat = parseWipMatchOpcodeMatcher(*Arg, Name)) {
-      if (!ParseAction(std::move(Pat)))
-        return false;
-      continue;
-    }
-
-    // Parse arbitrary C++ code
-    if (const auto *StringI = dyn_cast<StringInit>(Arg)) {
-      auto CXXPat = std::make_unique<CXXPattern>(*StringI, insertStrRef(Name));
-      if (!ParseAction(std::move(CXXPat)))
-        return false;
-      continue;
-    }
-
-    ::PrintError(DiagLoc,
-                 "Failed to parse pattern: '" + Arg->getAsString() + "'");
-    return false;
-  }
-
-  return true;
-}
-
-static const CodeGenInstruction &
-getInstrForIntrinsic(const CodeGenTarget &CGT, const CodeGenIntrinsic *I) {
-  StringRef Opc;
-  if (I->isConvergent) {
-    Opc = I->hasSideEffects ? "G_INTRINSIC_CONVERGENT_W_SIDE_EFFECTS"
-                            : "G_INTRINSIC_CONVERGENT";
-  } else {
-    Opc = I->hasSideEffects ? "G_INTRINSIC_W_SIDE_EFFECTS" : "G_INTRINSIC";
-  }
-
-  RecordKeeper &RK = I->TheDef->getRecords();
-  return CGT.getInstruction(RK.getDef(Opc));
-}
-
-static const CodeGenIntrinsic *getCodeGenIntrinsic(Record *R) {
-  // Intrinsics need to have a static lifetime because the match table keeps
-  // references to CodeGenIntrinsic objects.
-  static DenseMap<const Record *, std::unique_ptr<CodeGenIntrinsic>>
-      AllIntrinsics;
-
-  auto &Ptr = AllIntrinsics[R];
-  if (!Ptr)
-    Ptr = std::make_unique<CodeGenIntrinsic>(R, std::vector<Record *>());
-  return Ptr.get();
-}
-
-std::unique_ptr<Pattern>
-CombineRuleBuilder::parseInstructionPattern(const Init &Arg,
-                                            StringRef Name) const {
-  const DagInit *DagPat = dyn_cast<DagInit>(&Arg);
-  if (!DagPat)
-    return nullptr;
-
-  std::unique_ptr<InstructionPattern> Pat;
-  if (const DagInit *IP = getDagWithOperatorOfSubClass(Arg, "Instruction")) {
-    auto &Instr = CGT.getInstruction(IP->getOperatorAsDef(RuleDef.getLoc()));
-    Pat =
-        std::make_unique<CodeGenInstructionPattern>(Instr, insertStrRef(Name));
-  } else if (const DagInit *IP =
-                 getDagWithOperatorOfSubClass(Arg, "Intrinsic")) {
-    Record *TheDef = IP->getOperatorAsDef(RuleDef.getLoc());
-    const CodeGenIntrinsic *Intrin = getCodeGenIntrinsic(TheDef);
-    const CodeGenInstruction &Instr = getInstrForIntrinsic(CGT, Intrin);
-    Pat =
-        std::make_unique<CodeGenInstructionPattern>(Instr, insertStrRef(Name));
-    cast<CodeGenInstructionPattern>(*Pat).setIntrinsic(Intrin);
-  } else if (const DagInit *PFP =
-                 getDagWithOperatorOfSubClass(Arg, PatFrag::ClassName)) {
-    const Record *Def = PFP->getOperatorAsDef(RuleDef.getLoc());
-    const PatFrag *PF = parsePatFrag(Def);
-    if (!PF)
-      return nullptr; // Already diagnosed by parsePatFrag
-    Pat = std::make_unique<PatFragPattern>(*PF, insertStrRef(Name));
-  } else if (const DagInit *BP =
-                 getDagWithOperatorOfSubClass(Arg, BuiltinPattern::ClassName)) {
-    Pat = std::make_unique<BuiltinPattern>(
-        *BP->getOperatorAsDef(RuleDef.getLoc()), insertStrRef(Name));
-  } else
-    return nullptr;
-
-  for (unsigned K = 0; K < DagPat->getNumArgs(); ++K) {
-    Init *Arg = DagPat->getArg(K);
-    if (auto *DagArg = getDagWithSpecificOperator(*Arg, "MIFlags")) {
-      if (!parseInstructionPatternMIFlags(*Pat, DagArg))
-        return nullptr;
-      continue;
-    }
-
-    if (!parseInstructionPatternOperand(*Pat, Arg, DagPat->getArgName(K)))
-      return nullptr;
-  }
-
-  if (!Pat->checkSemantics(RuleDef.getLoc()))
-    return nullptr;
-
-  return std::move(Pat);
-}
-
-std::unique_ptr<Pattern>
-CombineRuleBuilder::parseWipMatchOpcodeMatcher(const Init &Arg,
-                                               StringRef Name) const {
-  const DagInit *Matcher = getDagWithSpecificOperator(Arg, "wip_match_opcode");
-  if (!Matcher)
-    return nullptr;
-
-  if (Matcher->getNumArgs() == 0) {
-    PrintError("Empty wip_match_opcode");
-    return nullptr;
-  }
-
-  // Each argument is an opcode that can match.
-  auto Result = std::make_unique<AnyOpcodePattern>(insertStrRef(Name));
-  for (const auto &Arg : Matcher->getArgs()) {
-    Record *OpcodeDef = getDefOfSubClass(*Arg, "Instruction");
-    if (OpcodeDef) {
-      Result->addOpcode(&CGT.getInstruction(OpcodeDef));
-      continue;
-    }
-
-    PrintError("Arguments to wip_match_opcode must be instructions");
-    return nullptr;
-  }
-
-  return std::move(Result);
-}
-
-bool CombineRuleBuilder::parseInstructionPatternOperand(
-    InstructionPattern &IP, const Init *OpInit,
-    const StringInit *OpName) const {
-  const auto ParseErr = [&]() {
-    PrintError("cannot parse operand '" + OpInit->getAsUnquotedString() + "' ");
-    if (OpName)
-      PrintNote("operand name is '" + OpName->getAsUnquotedString() + "'");
-    return false;
-  };
-
-  // untyped immediate, e.g. 0
-  if (const auto *IntImm = dyn_cast<IntInit>(OpInit)) {
-    std::string Name = OpName ? OpName->getAsUnquotedString() : "";
-    IP.addOperand(IntImm->getValue(), insertStrRef(Name), PatternType());
-    return true;
-  }
-
-  // typed immediate, e.g. (i32 0)
-  if (const auto *DagOp = dyn_cast<DagInit>(OpInit)) {
-    if (DagOp->getNumArgs() != 1)
-      return ParseErr();
-
-    const Record *TyDef = DagOp->getOperatorAsDef(RuleDef.getLoc());
-    auto ImmTy = PatternType::get(RuleDef.getLoc(), TyDef,
-                                  "cannot parse immediate '" +
-                                      DagOp->getAsUnquotedString() + "'");
-    if (!ImmTy)
-      return false;
-
-    if (!IP.hasAllDefs()) {
-      PrintError("out operand of '" + IP.getInstName() +
-                 "' cannot be an immediate");
-      return false;
-    }
-
-    const auto *Val = dyn_cast<IntInit>(DagOp->getArg(0));
-    if (!Val)
-      return ParseErr();
-
-    std::string Name = OpName ? OpName->getAsUnquotedString() : "";
-    IP.addOperand(Val->getValue(), insertStrRef(Name), *ImmTy);
-    return true;
-  }
-
-  // Typed operand e.g. $x/$z in (G_FNEG $x, $z)
-  if (auto *DefI = dyn_cast<DefInit>(OpInit)) {
-    if (!OpName) {
-      PrintError("expected an operand name after '" + OpInit->getAsString() +
-                 "'");
-      return false;
-    }
-    const Record *Def = DefI->getDef();
-    auto Ty =
-        PatternType::get(RuleDef.getLoc(), Def, "cannot parse operand type");
-    if (!Ty)
-      return false;
-    IP.addOperand(insertStrRef(OpName->getAsUnquotedString()), *Ty);
-    return true;
-  }
-
-  // Untyped operand e.g. $x/$z in (G_FNEG $x, $z)
-  if (isa<UnsetInit>(OpInit)) {
-    assert(OpName && "Unset w/ no OpName?");
-    IP.addOperand(insertStrRef(OpName->getAsUnquotedString()), PatternType());
-    return true;
-  }
-
-  return ParseErr();
-}
-
-bool CombineRuleBuilder::parseInstructionPatternMIFlags(
-    InstructionPattern &IP, const DagInit *Op) const {
-  auto *CGIP = dyn_cast<CodeGenInstructionPattern>(&IP);
-  if (!CGIP) {
-    PrintError("matching/writing MIFlags is only allowed on CodeGenInstruction "
-               "patterns");
-    return false;
-  }
-
-  const auto CheckFlagEnum = [&](const Record *R) {
-    if (!R->isSubClassOf(MIFlagsEnumClassName)) {
-      PrintError("'" + R->getName() + "' is not a subclass of '" +
-                 MIFlagsEnumClassName + "'");
-      return false;
-    }
-
-    return true;
-  };
-
-  if (CGIP->getMIFlagsInfo()) {
-    PrintError("MIFlags can only be present once on an instruction");
-    return false;
-  }
-
-  auto &FI = CGIP->getOrCreateMIFlagsInfo();
-  for (unsigned K = 0; K < Op->getNumArgs(); ++K) {
-    const Init *Arg = Op->getArg(K);
-
-    // Match/set a flag: (MIFlags FmNoNans)
-    if (const auto *Def = dyn_cast<DefInit>(Arg)) {
-      const Record *R = Def->getDef();
-      if (!CheckFlagEnum(R))
-        return false;
-
-      FI.addSetFlag(R);
-      continue;
-    }
-
-    // Do not match a flag/unset a flag: (MIFlags (not FmNoNans))
-    if (const DagInit *NotDag = getDagWithSpecificOperator(*Arg, "not")) {
-      for (const Init *NotArg : NotDag->getArgs()) {
-        const DefInit *DefArg = dyn_cast<DefInit>(NotArg);
-        if (!DefArg) {
-          PrintError("cannot parse '" + NotArg->getAsUnquotedString() +
-                     "': expected a '" + MIFlagsEnumClassName + "'");
-          return false;
-        }
-
-        const Record *R = DefArg->getDef();
-        if (!CheckFlagEnum(R))
-          return false;
-
-        FI.addUnsetFlag(R);
-        continue;
-      }
-
-      continue;
-    }
-
-    // Copy flags from a matched instruction: (MIFlags $mi)
-    if (isa<UnsetInit>(Arg)) {
-      FI.addCopyFlag(insertStrRef(Op->getArgName(K)->getAsUnquotedString()));
-      continue;
-    }
-  }
-
-  return true;
-}
-
-std::unique_ptr<PatFrag>
-CombineRuleBuilder::parsePatFragImpl(const Record *Def) const {
-  auto StackTrace = PrettyStackTraceParse(*Def);
-  if (!Def->isSubClassOf(PatFrag::ClassName))
-    return nullptr;
-
-  const DagInit *Ins = Def->getValueAsDag("InOperands");
-  if (Ins->getOperatorAsDef(Def->getLoc())->getName() != "ins") {
-    ::PrintError(Def, "expected 'ins' operator for " + PatFrag::ClassName +
-                          " in operands list");
-    return nullptr;
-  }
-
-  const DagInit *Outs = Def->getValueAsDag("OutOperands");
-  if (Outs->getOperatorAsDef(Def->getLoc())->getName() != "outs") {
-    ::PrintError(Def, "expected 'outs' operator for " + PatFrag::ClassName +
-                          " out operands list");
-    return nullptr;
-  }
-
-  auto Result = std::make_unique<PatFrag>(*Def);
-  if (!parsePatFragParamList(Def->getLoc(), *Outs,
-                             [&](StringRef Name, PatFrag::ParamKind Kind) {
-                               Result->addOutParam(insertStrRef(Name), Kind);
-                               return true;
-                             }))
-    return nullptr;
-
-  if (!parsePatFragParamList(Def->getLoc(), *Ins,
-                             [&](StringRef Name, PatFrag::ParamKind Kind) {
-                               Result->addInParam(insertStrRef(Name), Kind);
-                               return true;
-                             }))
-    return nullptr;
-
-  const ListInit *Alts = Def->getValueAsListInit("Alternatives");
-  unsigned AltIdx = 0;
-  for (const Init *Alt : *Alts) {
-    const auto *PatDag = dyn_cast<DagInit>(Alt);
-    if (!PatDag) {
-      ::PrintError(Def, "expected dag init for PatFrag pattern alternative");
-      return nullptr;
-    }
-
-    PatFrag::Alternative &A = Result->addAlternative();
-    const auto AddPat = [&](std::unique_ptr<Pattern> Pat) {
-      A.Pats.push_back(std::move(Pat));
-      return true;
-    };
-
-    if (!parsePatternList(
-            *PatDag, AddPat, "pattern", Def->getLoc(),
-            /*AnonPatPrefix*/
-            (Def->getName() + "_alt" + Twine(AltIdx++) + "_pattern").str()))
-      return nullptr;
-  }
-
-  if (!Result->buildOperandsTables() || !Result->checkSemantics())
-    return nullptr;
-
-  return Result;
-}
-
-bool CombineRuleBuilder::parsePatFragParamList(
-    ArrayRef<SMLoc> DiagLoc, const DagInit &OpsList,
-    function_ref<bool(StringRef, PatFrag::ParamKind)> ParseAction) const {
-  for (unsigned K = 0; K < OpsList.getNumArgs(); ++K) {
-    const StringInit *Name = OpsList.getArgName(K);
-    const Init *Ty = OpsList.getArg(K);
-
-    if (!Name) {
-      ::PrintError(DiagLoc, "all operands must be named'");
-      return false;
-    }
-    const std::string NameStr = Name->getAsUnquotedString();
-
-    PatFrag::ParamKind OpKind;
-    if (isSpecificDef(*Ty, "gi_imm"))
-      OpKind = PatFrag::PK_Imm;
-    else if (isSpecificDef(*Ty, "root"))
-      OpKind = PatFrag::PK_Root;
-    else if (isa<UnsetInit>(Ty) ||
-             isSpecificDef(*Ty, "gi_mo")) // no type = gi_mo.
-      OpKind = PatFrag::PK_MachineOperand;
-    else {
-      ::PrintError(
-          DiagLoc,
-          "'" + NameStr +
-              "' operand type was expected to be 'root', 'gi_imm' or 'gi_mo'");
-      return false;
-    }
-
-    if (!ParseAction(NameStr, OpKind))
-      return false;
-  }
-
-  return true;
-}
-
-const PatFrag *CombineRuleBuilder::parsePatFrag(const Record *Def) const {
-  // Cache already parsed PatFrags to avoid doing extra work.
-  static DenseMap<const Record *, std::unique_ptr<PatFrag>> ParsedPatFrags;
-
-  auto It = ParsedPatFrags.find(Def);
-  if (It != ParsedPatFrags.end()) {
-    SeenPatFrags.insert(It->second.get());
-    return It->second.get();
-  }
-
-  std::unique_ptr<PatFrag> NewPatFrag = parsePatFragImpl(Def);
-  if (!NewPatFrag) {
-    ::PrintError(Def, "Could not parse " + PatFrag::ClassName + " '" +
-                          Def->getName() + "'");
-    // Put a nullptr in the map so we don't attempt parsing this again.
-    ParsedPatFrags[Def] = nullptr;
-    return nullptr;
-  }
-
-  const auto *Res = NewPatFrag.get();
-  ParsedPatFrags[Def] = std::move(NewPatFrag);
-  SeenPatFrags.insert(Res);
-  return Res;
-}
-
 bool CombineRuleBuilder::emitMatchPattern(CodeExpansions &CE,
                                           const PatternAlternatives &Alts,
                                           const InstructionPattern &IP) {
@@ -2956,8 +2505,8 @@ GICombinerEmitter::buildMatchTable(MutableArrayRef<RuleMatcher> Rules) {
                                                const Matcher *B) {
     auto *L = static_cast<const RuleMatcher *>(A);
     auto *R = static_cast<const RuleMatcher *>(B);
-    return std::tuple(OpcodeOrder[L->getOpcode()], L->getNumOperands()) <
-           std::tuple(OpcodeOrder[R->getOpcode()], R->getNumOperands());
+    return std::make_tuple(OpcodeOrder[L->getOpcode()], L->getNumOperands()) <
+           std::make_tuple(OpcodeOrder[R->getOpcode()], R->getNumOperands());
   });
 
   for (Matcher *Rule : InputRules)