text: //===- PatternMatch.h - Match on the LLVM IR --------------------*- 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
  //
  //===----------------------------------------------------------------------===//
  //
  // This file provides a simple and efficient mechanism for performing general
  // tree-based pattern matches on the LLVM IR. The power of these routines is
  // that it allows you to write concise patterns that are expressive and easy to
  // understand. The other major advantage of this is that it allows you to
  // trivially capture/bind elements in the pattern to variables. For example,
  // you can do something like this:
  //
  //  Value *Exp = ...
  //  Value *X, *Y;  ConstantInt *C1, *C2;      // (X & C1) | (Y & C2)
  //  if (match(Exp, m_Or(m_And(m_Value(X), m_ConstantInt(C1)),
  //                      m_And(m_Value(Y), m_ConstantInt(C2))))) {
  //    ... Pattern is matched and variables are bound ...
  //  }
  //
  // This is primarily useful to things like the instruction combiner, but can
  // also be useful for static analysis tools or code generators.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_IR_PATTERNMATCH_H
  #define LLVM_IR_PATTERNMATCH_H
  
  #include "llvm/ADT/APFloat.h"
  #include "llvm/ADT/APInt.h"
  #include "llvm/IR/Constant.h"
  #include "llvm/IR/Constants.h"
  #include "llvm/IR/DataLayout.h"
  #include "llvm/IR/InstrTypes.h"
  #include "llvm/IR/Instruction.h"
  #include "llvm/IR/Instructions.h"
  #include "llvm/IR/IntrinsicInst.h"
  #include "llvm/IR/Intrinsics.h"
  #include "llvm/IR/Operator.h"
  #include "llvm/IR/Value.h"
  #include "llvm/Support/Casting.h"
  #include <cstdint>
  
  namespace llvm {
  namespace PatternMatch {
  
  template <typename Val, typename Pattern> bool match(Val *V, const Pattern &P) {
    return const_cast<Pattern &>(P).match(V);
  }
  
  template <typename Pattern> bool match(ArrayRef<int> Mask, const Pattern &P) {
    return const_cast<Pattern &>(P).match(Mask);
  }
  
  template <typename SubPattern_t> struct OneUse_match {
    SubPattern_t SubPattern;
  
    OneUse_match(const SubPattern_t &SP) : SubPattern(SP) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      return V->hasOneUse() && SubPattern.match(V);
    }
  };
  
  template <typename T> inline OneUse_match<T> m_OneUse(const T &SubPattern) {
    return SubPattern;
  }
  
  template <typename Class> struct class_match {
    template <typename ITy> bool match(ITy *V) { return isa<Class>(V); }
  };
  
  /// Match an arbitrary value and ignore it.
  inline class_match<Value> m_Value() { return class_match<Value>(); }
  
  /// Match an arbitrary unary operation and ignore it.
  inline class_match<UnaryOperator> m_UnOp() {
    return class_match<UnaryOperator>();
  }
  
  /// Match an arbitrary binary operation and ignore it.
  inline class_match<BinaryOperator> m_BinOp() {
    return class_match<BinaryOperator>();
  }
  
  /// Matches any compare instruction and ignore it.
  inline class_match<CmpInst> m_Cmp() { return class_match<CmpInst>(); }
  
  struct undef_match {
    static bool check(const Value *V) {
      if (isa<UndefValue>(V))
        return true;
  
      const auto *CA = dyn_cast<ConstantAggregate>(V);
      if (!CA)
        return false;
  
      SmallPtrSet<const ConstantAggregate *, 8> Seen;
      SmallVector<const ConstantAggregate *, 8> Worklist;
  
      // Either UndefValue, PoisonValue, or an aggregate that only contains
      // these is accepted by matcher.
      // CheckValue returns false if CA cannot satisfy this constraint.
      auto CheckValue = [&](const ConstantAggregate *CA) {
        for (const Value *Op : CA->operand_values()) {
          if (isa<UndefValue>(Op))
            continue;
  
          const auto *CA = dyn_cast<ConstantAggregate>(Op);
          if (!CA)
            return false;
          if (Seen.insert(CA).second)
            Worklist.emplace_back(CA);
        }
  
        return true;
      };
  
      if (!CheckValue(CA))
        return false;
  
      while (!Worklist.empty()) {
        if (!CheckValue(Worklist.pop_back_val()))
          return false;
      }
      return true;
    }
    template <typename ITy> bool match(ITy *V) { return check(V); }
  };
  
  /// Match an arbitrary undef constant. This matches poison as well.
  /// If this is an aggregate and contains a non-aggregate element that is
  /// neither undef nor poison, the aggregate is not matched.
  inline auto m_Undef() { return undef_match(); }
  
  /// Match an arbitrary poison constant.
  inline class_match<PoisonValue> m_Poison() { return class_match<PoisonValue>(); }
  
  /// Match an arbitrary Constant and ignore it.
  inline class_match<Constant> m_Constant() { return class_match<Constant>(); }
  
  /// Match an arbitrary ConstantInt and ignore it.
  inline class_match<ConstantInt> m_ConstantInt() {
    return class_match<ConstantInt>();
  }
  
  /// Match an arbitrary ConstantFP and ignore it.
  inline class_match<ConstantFP> m_ConstantFP() {
    return class_match<ConstantFP>();
  }
  
  /// Match an arbitrary ConstantExpr and ignore it.
  inline class_match<ConstantExpr> m_ConstantExpr() {
    return class_match<ConstantExpr>();
  }
  
  /// Match an arbitrary basic block value and ignore it.
  inline class_match<BasicBlock> m_BasicBlock() {
    return class_match<BasicBlock>();
  }
  
  /// Inverting matcher
  template <typename Ty> struct match_unless {
    Ty M;
  
    match_unless(const Ty &Matcher) : M(Matcher) {}
  
    template <typename ITy> bool match(ITy *V) { return !M.match(V); }
  };
  
  /// Match if the inner matcher does *NOT* match.
  template <typename Ty> inline match_unless<Ty> m_Unless(const Ty &M) {
    return match_unless<Ty>(M);
  }
  
  /// Matching combinators
  template <typename LTy, typename RTy> struct match_combine_or {
    LTy L;
    RTy R;
  
    match_combine_or(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (L.match(V))
        return true;
      if (R.match(V))
        return true;
      return false;
    }
  };
  
  template <typename LTy, typename RTy> struct match_combine_and {
    LTy L;
    RTy R;
  
    match_combine_and(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (L.match(V))
        if (R.match(V))
          return true;
      return false;
    }
  };
  
  /// Combine two pattern matchers matching L || R
  template <typename LTy, typename RTy>
  inline match_combine_or<LTy, RTy> m_CombineOr(const LTy &L, const RTy &R) {
    return match_combine_or<LTy, RTy>(L, R);
  }
  
  /// Combine two pattern matchers matching L && R
  template <typename LTy, typename RTy>
  inline match_combine_and<LTy, RTy> m_CombineAnd(const LTy &L, const RTy &R) {
    return match_combine_and<LTy, RTy>(L, R);
  }
  
  struct apint_match {
    const APInt *&Res;
    bool AllowUndef;
  
    apint_match(const APInt *&Res, bool AllowUndef)
      : Res(Res), AllowUndef(AllowUndef) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (auto *CI = dyn_cast<ConstantInt>(V)) {
        Res = &CI->getValue();
        return true;
      }
      if (V->getType()->isVectorTy())
        if (const auto *C = dyn_cast<Constant>(V))
          if (auto *CI = dyn_cast_or_null<ConstantInt>(
                  C->getSplatValue(AllowUndef))) {
            Res = &CI->getValue();
            return true;
          }
      return false;
    }
  };
  // Either constexpr if or renaming ConstantFP::getValueAPF to
  // ConstantFP::getValue is needed to do it via single template
  // function for both apint/apfloat.
  struct apfloat_match {
    const APFloat *&Res;
    bool AllowUndef;
  
    apfloat_match(const APFloat *&Res, bool AllowUndef)
        : Res(Res), AllowUndef(AllowUndef) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (auto *CI = dyn_cast<ConstantFP>(V)) {
        Res = &CI->getValueAPF();
        return true;
      }
      if (V->getType()->isVectorTy())
        if (const auto *C = dyn_cast<Constant>(V))
          if (auto *CI = dyn_cast_or_null<ConstantFP>(
                  C->getSplatValue(AllowUndef))) {
            Res = &CI->getValueAPF();
            return true;
          }
      return false;
    }
  };
  
  /// Match a ConstantInt or splatted ConstantVector, binding the
  /// specified pointer to the contained APInt.
  inline apint_match m_APInt(const APInt *&Res) {
    // Forbid undefs by default to maintain previous behavior.
    return apint_match(Res, /* AllowUndef */ false);
  }
  
  /// Match APInt while allowing undefs in splat vector constants.
  inline apint_match m_APIntAllowUndef(const APInt *&Res) {
    return apint_match(Res, /* AllowUndef */ true);
  }
  
  /// Match APInt while forbidding undefs in splat vector constants.
  inline apint_match m_APIntForbidUndef(const APInt *&Res) {
    return apint_match(Res, /* AllowUndef */ false);
  }
  
  /// Match a ConstantFP or splatted ConstantVector, binding the
  /// specified pointer to the contained APFloat.
  inline apfloat_match m_APFloat(const APFloat *&Res) {
    // Forbid undefs by default to maintain previous behavior.
    return apfloat_match(Res, /* AllowUndef */ false);
  }
  
  /// Match APFloat while allowing undefs in splat vector constants.
  inline apfloat_match m_APFloatAllowUndef(const APFloat *&Res) {
    return apfloat_match(Res, /* AllowUndef */ true);
  }
  
  /// Match APFloat while forbidding undefs in splat vector constants.
  inline apfloat_match m_APFloatForbidUndef(const APFloat *&Res) {
    return apfloat_match(Res, /* AllowUndef */ false);
  }
  
  template <int64_t Val> struct constantint_match {
    template <typename ITy> bool match(ITy *V) {
      if (const auto *CI = dyn_cast<ConstantInt>(V)) {
        const APInt &CIV = CI->getValue();
        if (Val >= 0)
          return CIV == static_cast<uint64_t>(Val);
        // If Val is negative, and CI is shorter than it, truncate to the right
        // number of bits.  If it is larger, then we have to sign extend.  Just
        // compare their negated values.
        return -CIV == -Val;
      }
      return false;
    }
  };
  
  /// Match a ConstantInt with a specific value.
  template <int64_t Val> inline constantint_match<Val> m_ConstantInt() {
    return constantint_match<Val>();
  }
  
  /// This helper class is used to match constant scalars, vector splats,
  /// and fixed width vectors that satisfy a specified predicate.
  /// For fixed width vector constants, undefined elements are ignored.
  template <typename Predicate, typename ConstantVal>
  struct cstval_pred_ty : public Predicate {
    template <typename ITy> bool match(ITy *V) {
      if (const auto *CV = dyn_cast<ConstantVal>(V))
        return this->isValue(CV->getValue());
      if (const auto *VTy = dyn_cast<VectorType>(V->getType())) {
        if (const auto *C = dyn_cast<Constant>(V)) {
          if (const auto *CV = dyn_cast_or_null<ConstantVal>(C->getSplatValue()))
            return this->isValue(CV->getValue());
  
          // Number of elements of a scalable vector unknown at compile time
          auto *FVTy = dyn_cast<FixedVectorType>(VTy);
          if (!FVTy)
            return false;
  
          // Non-splat vector constant: check each element for a match.
          unsigned NumElts = FVTy->getNumElements();
          assert(NumElts != 0 && "Constant vector with no elements?");
          bool HasNonUndefElements = false;
          for (unsigned i = 0; i != NumElts; ++i) {
            Constant *Elt = C->getAggregateElement(i);
            if (!Elt)
              return false;
            if (isa<UndefValue>(Elt))
              continue;
            auto *CV = dyn_cast<ConstantVal>(Elt);
            if (!CV || !this->isValue(CV->getValue()))
              return false;
            HasNonUndefElements = true;
          }
          return HasNonUndefElements;
        }
      }
      return false;
    }
  };
  
  /// specialization of cstval_pred_ty for ConstantInt
  template <typename Predicate>
  using cst_pred_ty = cstval_pred_ty<Predicate, ConstantInt>;
  
  /// specialization of cstval_pred_ty for ConstantFP
  template <typename Predicate>
  using cstfp_pred_ty = cstval_pred_ty<Predicate, ConstantFP>;
  
  /// This helper class is used to match scalar and vector constants that
  /// satisfy a specified predicate, and bind them to an APInt.
  template <typename Predicate> struct api_pred_ty : public Predicate {
    const APInt *&Res;
  
    api_pred_ty(const APInt *&R) : Res(R) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (const auto *CI = dyn_cast<ConstantInt>(V))
        if (this->isValue(CI->getValue())) {
          Res = &CI->getValue();
          return true;
        }
      if (V->getType()->isVectorTy())
        if (const auto *C = dyn_cast<Constant>(V))
          if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
            if (this->isValue(CI->getValue())) {
              Res = &CI->getValue();
              return true;
            }
  
      return false;
    }
  };
  
  /// This helper class is used to match scalar and vector constants that
  /// satisfy a specified predicate, and bind them to an APFloat.
  /// Undefs are allowed in splat vector constants.
  template <typename Predicate> struct apf_pred_ty : public Predicate {
    const APFloat *&Res;
  
    apf_pred_ty(const APFloat *&R) : Res(R) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (const auto *CI = dyn_cast<ConstantFP>(V))
        if (this->isValue(CI->getValue())) {
          Res = &CI->getValue();
          return true;
        }
      if (V->getType()->isVectorTy())
        if (const auto *C = dyn_cast<Constant>(V))
          if (auto *CI = dyn_cast_or_null<ConstantFP>(
                  C->getSplatValue(/* AllowUndef */ true)))
            if (this->isValue(CI->getValue())) {
              Res = &CI->getValue();
              return true;
            }
  
      return false;
    }
  };
  
  ///////////////////////////////////////////////////////////////////////////////
  //
  // Encapsulate constant value queries for use in templated predicate matchers.
  // This allows checking if constants match using compound predicates and works
  // with vector constants, possibly with relaxed constraints. For example, ignore
  // undef values.
  //
  ///////////////////////////////////////////////////////////////////////////////
  
  struct is_any_apint {
    bool isValue(const APInt &C) { return true; }
  };
  /// Match an integer or vector with any integral constant.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_any_apint> m_AnyIntegralConstant() {
    return cst_pred_ty<is_any_apint>();
  }
  
  struct is_all_ones {
    bool isValue(const APInt &C) { return C.isAllOnesValue(); }
  };
  /// Match an integer or vector with all bits set.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_all_ones> m_AllOnes() {
    return cst_pred_ty<is_all_ones>();
  }
  
  struct is_maxsignedvalue {
    bool isValue(const APInt &C) { return C.isMaxSignedValue(); }
  };
  /// Match an integer or vector with values having all bits except for the high
  /// bit set (0x7f...).
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_maxsignedvalue> m_MaxSignedValue() {
    return cst_pred_ty<is_maxsignedvalue>();
  }
  inline api_pred_ty<is_maxsignedvalue> m_MaxSignedValue(const APInt *&V) {
    return V;
  }
  
  struct is_negative {
    bool isValue(const APInt &C) { return C.isNegative(); }
  };
  /// Match an integer or vector of negative values.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_negative> m_Negative() {
    return cst_pred_ty<is_negative>();
  }
  inline api_pred_ty<is_negative> m_Negative(const APInt *&V) {
    return V;
  }
  
  struct is_nonnegative {
    bool isValue(const APInt &C) { return C.isNonNegative(); }
  };
  /// Match an integer or vector of non-negative values.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_nonnegative> m_NonNegative() {
    return cst_pred_ty<is_nonnegative>();
  }
  inline api_pred_ty<is_nonnegative> m_NonNegative(const APInt *&V) {
    return V;
  }
  
  struct is_strictlypositive {
    bool isValue(const APInt &C) { return C.isStrictlyPositive(); }
  };
  /// Match an integer or vector of strictly positive values.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_strictlypositive> m_StrictlyPositive() {
    return cst_pred_ty<is_strictlypositive>();
  }
  inline api_pred_ty<is_strictlypositive> m_StrictlyPositive(const APInt *&V) {
    return V;
  }
  
  struct is_nonpositive {
    bool isValue(const APInt &C) { return C.isNonPositive(); }
  };
  /// Match an integer or vector of non-positive values.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_nonpositive> m_NonPositive() {
    return cst_pred_ty<is_nonpositive>();
  }
  inline api_pred_ty<is_nonpositive> m_NonPositive(const APInt *&V) { return V; }
  
  struct is_one {
    bool isValue(const APInt &C) { return C.isOneValue(); }
  };
  /// Match an integer 1 or a vector with all elements equal to 1.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_one> m_One() {
    return cst_pred_ty<is_one>();
  }
  
  struct is_zero_int {
    bool isValue(const APInt &C) { return C.isNullValue(); }
  };
  /// Match an integer 0 or a vector with all elements equal to 0.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_zero_int> m_ZeroInt() {
    return cst_pred_ty<is_zero_int>();
  }
  
  struct is_zero {
    template <typename ITy> bool match(ITy *V) {
      auto *C = dyn_cast<Constant>(V);
      // FIXME: this should be able to do something for scalable vectors
      return C && (C->isNullValue() || cst_pred_ty<is_zero_int>().match(C));
    }
  };
  /// Match any null constant or a vector with all elements equal to 0.
  /// For vectors, this includes constants with undefined elements.
  inline is_zero m_Zero() {
    return is_zero();
  }
  
  struct is_power2 {
    bool isValue(const APInt &C) { return C.isPowerOf2(); }
  };
  /// Match an integer or vector power-of-2.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_power2> m_Power2() {
    return cst_pred_ty<is_power2>();
  }
  inline api_pred_ty<is_power2> m_Power2(const APInt *&V) {
    return V;
  }
  
  struct is_negated_power2 {
    bool isValue(const APInt &C) { return (-C).isPowerOf2(); }
  };
  /// Match a integer or vector negated power-of-2.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_negated_power2> m_NegatedPower2() {
    return cst_pred_ty<is_negated_power2>();
  }
  inline api_pred_ty<is_negated_power2> m_NegatedPower2(const APInt *&V) {
    return V;
  }
  
  struct is_power2_or_zero {
    bool isValue(const APInt &C) { return !C || C.isPowerOf2(); }
  };
  /// Match an integer or vector of 0 or power-of-2 values.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_power2_or_zero> m_Power2OrZero() {
    return cst_pred_ty<is_power2_or_zero>();
  }
  inline api_pred_ty<is_power2_or_zero> m_Power2OrZero(const APInt *&V) {
    return V;
  }
  
  struct is_sign_mask {
    bool isValue(const APInt &C) { return C.isSignMask(); }
  };
  /// Match an integer or vector with only the sign bit(s) set.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_sign_mask> m_SignMask() {
    return cst_pred_ty<is_sign_mask>();
  }
  
  struct is_lowbit_mask {
    bool isValue(const APInt &C) { return C.isMask(); }
  };
  /// Match an integer or vector with only the low bit(s) set.
  /// For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<is_lowbit_mask> m_LowBitMask() {
    return cst_pred_ty<is_lowbit_mask>();
  }
  
  struct icmp_pred_with_threshold {
    ICmpInst::Predicate Pred;
    const APInt *Thr;
    bool isValue(const APInt &C) {
      switch (Pred) {
      case ICmpInst::Predicate::ICMP_EQ:
        return C.eq(*Thr);
      case ICmpInst::Predicate::ICMP_NE:
        return C.ne(*Thr);
      case ICmpInst::Predicate::ICMP_UGT:
        return C.ugt(*Thr);
      case ICmpInst::Predicate::ICMP_UGE:
        return C.uge(*Thr);
      case ICmpInst::Predicate::ICMP_ULT:
        return C.ult(*Thr);
      case ICmpInst::Predicate::ICMP_ULE:
        return C.ule(*Thr);
      case ICmpInst::Predicate::ICMP_SGT:
        return C.sgt(*Thr);
      case ICmpInst::Predicate::ICMP_SGE:
        return C.sge(*Thr);
      case ICmpInst::Predicate::ICMP_SLT:
        return C.slt(*Thr);
      case ICmpInst::Predicate::ICMP_SLE:
        return C.sle(*Thr);
      default:
        llvm_unreachable("Unhandled ICmp predicate");
      }
    }
  };
  /// Match an integer or vector with every element comparing 'pred' (eg/ne/...)
  /// to Threshold. For vectors, this includes constants with undefined elements.
  inline cst_pred_ty<icmp_pred_with_threshold>
  m_SpecificInt_ICMP(ICmpInst::Predicate Predicate, const APInt &Threshold) {
    cst_pred_ty<icmp_pred_with_threshold> P;
    P.Pred = Predicate;
    P.Thr = &Threshold;
    return P;
  }
  
  struct is_nan {
    bool isValue(const APFloat &C) { return C.isNaN(); }
  };
  /// Match an arbitrary NaN constant. This includes quiet and signalling nans.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_nan> m_NaN() {
    return cstfp_pred_ty<is_nan>();
  }
  
  struct is_nonnan {
    bool isValue(const APFloat &C) { return !C.isNaN(); }
  };
  /// Match a non-NaN FP constant.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_nonnan> m_NonNaN() {
    return cstfp_pred_ty<is_nonnan>();
  }
  
  struct is_inf {
    bool isValue(const APFloat &C) { return C.isInfinity(); }
  };
  /// Match a positive or negative infinity FP constant.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_inf> m_Inf() {
    return cstfp_pred_ty<is_inf>();
  }
  
  struct is_noninf {
    bool isValue(const APFloat &C) { return !C.isInfinity(); }
  };
  /// Match a non-infinity FP constant, i.e. finite or NaN.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_noninf> m_NonInf() {
    return cstfp_pred_ty<is_noninf>();
  }
  
  struct is_finite {
    bool isValue(const APFloat &C) { return C.isFinite(); }
  };
  /// Match a finite FP constant, i.e. not infinity or NaN.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_finite> m_Finite() {
    return cstfp_pred_ty<is_finite>();
  }
  inline apf_pred_ty<is_finite> m_Finite(const APFloat *&V) { return V; }
  
  struct is_finitenonzero {
    bool isValue(const APFloat &C) { return C.isFiniteNonZero(); }
  };
  /// Match a finite non-zero FP constant.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_finitenonzero> m_FiniteNonZero() {
    return cstfp_pred_ty<is_finitenonzero>();
  }
  inline apf_pred_ty<is_finitenonzero> m_FiniteNonZero(const APFloat *&V) {
    return V;
  }
  
  struct is_any_zero_fp {
    bool isValue(const APFloat &C) { return C.isZero(); }
  };
  /// Match a floating-point negative zero or positive zero.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_any_zero_fp> m_AnyZeroFP() {
    return cstfp_pred_ty<is_any_zero_fp>();
  }
  
  struct is_pos_zero_fp {
    bool isValue(const APFloat &C) { return C.isPosZero(); }
  };
  /// Match a floating-point positive zero.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_pos_zero_fp> m_PosZeroFP() {
    return cstfp_pred_ty<is_pos_zero_fp>();
  }
  
  struct is_neg_zero_fp {
    bool isValue(const APFloat &C) { return C.isNegZero(); }
  };
  /// Match a floating-point negative zero.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_neg_zero_fp> m_NegZeroFP() {
    return cstfp_pred_ty<is_neg_zero_fp>();
  }
  
  struct is_non_zero_fp {
    bool isValue(const APFloat &C) { return C.isNonZero(); }
  };
  /// Match a floating-point non-zero.
  /// For vectors, this includes constants with undefined elements.
  inline cstfp_pred_ty<is_non_zero_fp> m_NonZeroFP() {
    return cstfp_pred_ty<is_non_zero_fp>();
  }
  
  ///////////////////////////////////////////////////////////////////////////////
  
  template <typename Class> struct bind_ty {
    Class *&VR;
  
    bind_ty(Class *&V) : VR(V) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (auto *CV = dyn_cast<Class>(V)) {
        VR = CV;
        return true;
      }
      return false;
    }
  };
  
  /// Match a value, capturing it if we match.
  inline bind_ty<Value> m_Value(Value *&V) { return V; }
  inline bind_ty<const Value> m_Value(const Value *&V) { return V; }
  
  /// Match an instruction, capturing it if we match.
  inline bind_ty<Instruction> m_Instruction(Instruction *&I) { return I; }
  /// Match a unary operator, capturing it if we match.
  inline bind_ty<UnaryOperator> m_UnOp(UnaryOperator *&I) { return I; }
  /// Match a binary operator, capturing it if we match.
  inline bind_ty<BinaryOperator> m_BinOp(BinaryOperator *&I) { return I; }
  /// Match a with overflow intrinsic, capturing it if we match.
  inline bind_ty<WithOverflowInst> m_WithOverflowInst(WithOverflowInst *&I) { return I; }
  inline bind_ty<const WithOverflowInst>
  m_WithOverflowInst(const WithOverflowInst *&I) {
    return I;
  }
  
  /// Match a Constant, capturing the value if we match.
  inline bind_ty<Constant> m_Constant(Constant *&C) { return C; }
  
  /// Match a ConstantInt, capturing the value if we match.
  inline bind_ty<ConstantInt> m_ConstantInt(ConstantInt *&CI) { return CI; }
  
  /// Match a ConstantFP, capturing the value if we match.
  inline bind_ty<ConstantFP> m_ConstantFP(ConstantFP *&C) { return C; }
  
  /// Match a ConstantExpr, capturing the value if we match.
  inline bind_ty<ConstantExpr> m_ConstantExpr(ConstantExpr *&C) { return C; }
  
  /// Match a basic block value, capturing it if we match.
  inline bind_ty<BasicBlock> m_BasicBlock(BasicBlock *&V) { return V; }
  inline bind_ty<const BasicBlock> m_BasicBlock(const BasicBlock *&V) {
    return V;
  }
  
  /// Match an arbitrary immediate Constant and ignore it.
  inline match_combine_and<class_match<Constant>,
                           match_unless<class_match<ConstantExpr>>>
  m_ImmConstant() {
    return m_CombineAnd(m_Constant(), m_Unless(m_ConstantExpr()));
  }
  
  /// Match an immediate Constant, capturing the value if we match.
  inline match_combine_and<bind_ty<Constant>,
                           match_unless<class_match<ConstantExpr>>>
  m_ImmConstant(Constant *&C) {
    return m_CombineAnd(m_Constant(C), m_Unless(m_ConstantExpr()));
  }
  
  /// Match a specified Value*.
  struct specificval_ty {
    const Value *Val;
  
    specificval_ty(const Value *V) : Val(V) {}
  
    template <typename ITy> bool match(ITy *V) { return V == Val; }
  };
  
  /// Match if we have a specific specified value.
  inline specificval_ty m_Specific(const Value *V) { return V; }
  
  /// Stores a reference to the Value *, not the Value * itself,
  /// thus can be used in commutative matchers.
  template <typename Class> struct deferredval_ty {
    Class *const &Val;
  
    deferredval_ty(Class *const &V) : Val(V) {}
  
    template <typename ITy> bool match(ITy *const V) { return V == Val; }
  };
  
  /// A commutative-friendly version of m_Specific().
  inline deferredval_ty<Value> m_Deferred(Value *const &V) { return V; }
  inline deferredval_ty<const Value> m_Deferred(const Value *const &V) {
    return V;
  }
  
  /// Match a specified floating point value or vector of all elements of
  /// that value.
  struct specific_fpval {
    double Val;
  
    specific_fpval(double V) : Val(V) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (const auto *CFP = dyn_cast<ConstantFP>(V))
        return CFP->isExactlyValue(Val);
      if (V->getType()->isVectorTy())
        if (const auto *C = dyn_cast<Constant>(V))
          if (auto *CFP = dyn_cast_or_null<ConstantFP>(C->getSplatValue()))
            return CFP->isExactlyValue(Val);
      return false;
    }
  };
  
  /// Match a specific floating point value or vector with all elements
  /// equal to the value.
  inline specific_fpval m_SpecificFP(double V) { return specific_fpval(V); }
  
  /// Match a float 1.0 or vector with all elements equal to 1.0.
  inline specific_fpval m_FPOne() { return m_SpecificFP(1.0); }
  
  struct bind_const_intval_ty {
    uint64_t &VR;
  
    bind_const_intval_ty(uint64_t &V) : VR(V) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (const auto *CV = dyn_cast<ConstantInt>(V))
        if (CV->getValue().ule(UINT64_MAX)) {
          VR = CV->getZExtValue();
          return true;
        }
      return false;
    }
  };
  
  /// Match a specified integer value or vector of all elements of that
  /// value.
  template <bool AllowUndefs>
  struct specific_intval {
    APInt Val;
  
    specific_intval(APInt V) : Val(std::move(V)) {}
  
    template <typename ITy> bool match(ITy *V) {
      const auto *CI = dyn_cast<ConstantInt>(V);
      if (!CI && V->getType()->isVectorTy())
        if (const auto *C = dyn_cast<Constant>(V))
          CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue(AllowUndefs));
  
      return CI && APInt::isSameValue(CI->getValue(), Val);
    }
  };
  
  /// Match a specific integer value or vector with all elements equal to
  /// the value.
  inline specific_intval<false> m_SpecificInt(APInt V) {
    return specific_intval<false>(std::move(V));
  }
  
  inline specific_intval<false> m_SpecificInt(uint64_t V) {
    return m_SpecificInt(APInt(64, V));
  }
  
  inline specific_intval<true> m_SpecificIntAllowUndef(APInt V) {
    return specific_intval<true>(std::move(V));
  }
  
  inline specific_intval<true> m_SpecificIntAllowUndef(uint64_t V) {
    return m_SpecificIntAllowUndef(APInt(64, V));
  }
  
  /// Match a ConstantInt and bind to its value.  This does not match
  /// ConstantInts wider than 64-bits.
  inline bind_const_intval_ty m_ConstantInt(uint64_t &V) { return V; }
  
  /// Match a specified basic block value.
  struct specific_bbval {
    BasicBlock *Val;
  
    specific_bbval(BasicBlock *Val) : Val(Val) {}
  
    template <typename ITy> bool match(ITy *V) {
      const auto *BB = dyn_cast<BasicBlock>(V);
      return BB && BB == Val;
    }
  };
  
  /// Match a specific basic block value.
  inline specific_bbval m_SpecificBB(BasicBlock *BB) {
    return specific_bbval(BB);
  }
  
  /// A commutative-friendly version of m_Specific().
  inline deferredval_ty<BasicBlock> m_Deferred(BasicBlock *const &BB) {
    return BB;
  }
  inline deferredval_ty<const BasicBlock>
  m_Deferred(const BasicBlock *const &BB) {
    return BB;
  }
  
  //===----------------------------------------------------------------------===//
  // Matcher for any binary operator.
  //
  template <typename LHS_t, typename RHS_t, bool Commutable = false>
  struct AnyBinaryOp_match {
    LHS_t L;
    RHS_t R;
  
    // The evaluation order is always stable, regardless of Commutability.
    // The LHS is always matched first.
    AnyBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *I = dyn_cast<BinaryOperator>(V))
        return (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
               (Commutable && L.match(I->getOperand(1)) &&
                R.match(I->getOperand(0)));
      return false;
    }
  };
  
  template <typename LHS, typename RHS>
  inline AnyBinaryOp_match<LHS, RHS> m_BinOp(const LHS &L, const RHS &R) {
    return AnyBinaryOp_match<LHS, RHS>(L, R);
  }
  
  //===----------------------------------------------------------------------===//
  // Matcher for any unary operator.
  // TODO fuse unary, binary matcher into n-ary matcher
  //
  template <typename OP_t> struct AnyUnaryOp_match {
    OP_t X;
  
    AnyUnaryOp_match(const OP_t &X) : X(X) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *I = dyn_cast<UnaryOperator>(V))
        return X.match(I->getOperand(0));
      return false;
    }
  };
  
  template <typename OP_t> inline AnyUnaryOp_match<OP_t> m_UnOp(const OP_t &X) {
    return AnyUnaryOp_match<OP_t>(X);
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for specific binary operators.
  //
  
  template <typename LHS_t, typename RHS_t, unsigned Opcode,
            bool Commutable = false>
  struct BinaryOp_match {
    LHS_t L;
    RHS_t R;
  
    // The evaluation order is always stable, regardless of Commutability.
    // The LHS is always matched first.
    BinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (V->getValueID() == Value::InstructionVal + Opcode) {
        auto *I = cast<BinaryOperator>(V);
        return (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
               (Commutable && L.match(I->getOperand(1)) &&
                R.match(I->getOperand(0)));
      }
      if (auto *CE = dyn_cast<ConstantExpr>(V))
        return CE->getOpcode() == Opcode &&
               ((L.match(CE->getOperand(0)) && R.match(CE->getOperand(1))) ||
                (Commutable && L.match(CE->getOperand(1)) &&
                 R.match(CE->getOperand(0))));
      return false;
    }
  };
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Add> m_Add(const LHS &L,
                                                          const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Add>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::FAdd> m_FAdd(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::FAdd>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Sub> m_Sub(const LHS &L,
                                                          const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Sub>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::FSub> m_FSub(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::FSub>(L, R);
  }
  
  template <typename Op_t> struct FNeg_match {
    Op_t X;
  
    FNeg_match(const Op_t &Op) : X(Op) {}
    template <typename OpTy> bool match(OpTy *V) {
      auto *FPMO = dyn_cast<FPMathOperator>(V);
      if (!FPMO) return false;
  
      if (FPMO->getOpcode() == Instruction::FNeg)
        return X.match(FPMO->getOperand(0));
  
      if (FPMO->getOpcode() == Instruction::FSub) {
        if (FPMO->hasNoSignedZeros()) {
          // With 'nsz', any zero goes.
          if (!cstfp_pred_ty<is_any_zero_fp>().match(FPMO->getOperand(0)))
            return false;
        } else {
          // Without 'nsz', we need fsub -0.0, X exactly.
          if (!cstfp_pred_ty<is_neg_zero_fp>().match(FPMO->getOperand(0)))
            return false;
        }
  
        return X.match(FPMO->getOperand(1));
      }
  
      return false;
    }
  };
  
  /// Match 'fneg X' as 'fsub -0.0, X'.
  template <typename OpTy>
  inline FNeg_match<OpTy>
  m_FNeg(const OpTy &X) {
    return FNeg_match<OpTy>(X);
  }
  
  /// Match 'fneg X' as 'fsub +-0.0, X'.
  template <typename RHS>
  inline BinaryOp_match<cstfp_pred_ty<is_any_zero_fp>, RHS, Instruction::FSub>
  m_FNegNSZ(const RHS &X) {
    return m_FSub(m_AnyZeroFP(), X);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Mul> m_Mul(const LHS &L,
                                                          const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Mul>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::FMul> m_FMul(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::FMul>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::UDiv> m_UDiv(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::UDiv>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::SDiv> m_SDiv(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::SDiv>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::FDiv> m_FDiv(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::FDiv>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::URem> m_URem(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::URem>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::SRem> m_SRem(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::SRem>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::FRem> m_FRem(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::FRem>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::And> m_And(const LHS &L,
                                                          const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::And>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Or> m_Or(const LHS &L,
                                                        const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Or>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Xor> m_Xor(const LHS &L,
                                                          const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Xor>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Shl> m_Shl(const LHS &L,
                                                          const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Shl>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::LShr> m_LShr(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::LShr>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::AShr> m_AShr(const LHS &L,
                                                            const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::AShr>(L, R);
  }
  
  template <typename LHS_t, typename RHS_t, unsigned Opcode,
            unsigned WrapFlags = 0>
  struct OverflowingBinaryOp_match {
    LHS_t L;
    RHS_t R;
  
    OverflowingBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS)
        : L(LHS), R(RHS) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *Op = dyn_cast<OverflowingBinaryOperator>(V)) {
        if (Op->getOpcode() != Opcode)
          return false;
        if (WrapFlags & OverflowingBinaryOperator::NoUnsignedWrap &&
            !Op->hasNoUnsignedWrap())
          return false;
        if (WrapFlags & OverflowingBinaryOperator::NoSignedWrap &&
            !Op->hasNoSignedWrap())
          return false;
        return L.match(Op->getOperand(0)) && R.match(Op->getOperand(1));
      }
      return false;
    }
  };
  
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
                                   OverflowingBinaryOperator::NoSignedWrap>
  m_NSWAdd(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
                                     OverflowingBinaryOperator::NoSignedWrap>(
        L, R);
  }
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
                                   OverflowingBinaryOperator::NoSignedWrap>
  m_NSWSub(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
                                     OverflowingBinaryOperator::NoSignedWrap>(
        L, R);
  }
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
                                   OverflowingBinaryOperator::NoSignedWrap>
  m_NSWMul(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
                                     OverflowingBinaryOperator::NoSignedWrap>(
        L, R);
  }
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
                                   OverflowingBinaryOperator::NoSignedWrap>
  m_NSWShl(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
                                     OverflowingBinaryOperator::NoSignedWrap>(
        L, R);
  }
  
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
                                   OverflowingBinaryOperator::NoUnsignedWrap>
  m_NUWAdd(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
                                     OverflowingBinaryOperator::NoUnsignedWrap>(
        L, R);
  }
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
                                   OverflowingBinaryOperator::NoUnsignedWrap>
  m_NUWSub(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
                                     OverflowingBinaryOperator::NoUnsignedWrap>(
        L, R);
  }
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
                                   OverflowingBinaryOperator::NoUnsignedWrap>
  m_NUWMul(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
                                     OverflowingBinaryOperator::NoUnsignedWrap>(
        L, R);
  }
  template <typename LHS, typename RHS>
  inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
                                   OverflowingBinaryOperator::NoUnsignedWrap>
  m_NUWShl(const LHS &L, const RHS &R) {
    return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
                                     OverflowingBinaryOperator::NoUnsignedWrap>(
        L, R);
  }
  
  //===----------------------------------------------------------------------===//
  // Class that matches a group of binary opcodes.
  //
  template <typename LHS_t, typename RHS_t, typename Predicate>
  struct BinOpPred_match : Predicate {
    LHS_t L;
    RHS_t R;
  
    BinOpPred_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *I = dyn_cast<Instruction>(V))
        return this->isOpType(I->getOpcode()) && L.match(I->getOperand(0)) &&
               R.match(I->getOperand(1));
      if (auto *CE = dyn_cast<ConstantExpr>(V))
        return this->isOpType(CE->getOpcode()) && L.match(CE->getOperand(0)) &&
               R.match(CE->getOperand(1));
      return false;
    }
  };
  
  struct is_shift_op {
    bool isOpType(unsigned Opcode) { return Instruction::isShift(Opcode); }
  };
  
  struct is_right_shift_op {
    bool isOpType(unsigned Opcode) {
      return Opcode == Instruction::LShr || Opcode == Instruction::AShr;
    }
  };
  
  struct is_logical_shift_op {
    bool isOpType(unsigned Opcode) {
      return Opcode == Instruction::LShr || Opcode == Instruction::Shl;
    }
  };
  
  struct is_bitwiselogic_op {
    bool isOpType(unsigned Opcode) {
      return Instruction::isBitwiseLogicOp(Opcode);
    }
  };
  
  struct is_idiv_op {
    bool isOpType(unsigned Opcode) {
      return Opcode == Instruction::SDiv || Opcode == Instruction::UDiv;
    }
  };
  
  struct is_irem_op {
    bool isOpType(unsigned Opcode) {
      return Opcode == Instruction::SRem || Opcode == Instruction::URem;
    }
  };
  
  /// Matches shift operations.
  template <typename LHS, typename RHS>
  inline BinOpPred_match<LHS, RHS, is_shift_op> m_Shift(const LHS &L,
                                                        const RHS &R) {
    return BinOpPred_match<LHS, RHS, is_shift_op>(L, R);
  }
  
  /// Matches logical shift operations.
  template <typename LHS, typename RHS>
  inline BinOpPred_match<LHS, RHS, is_right_shift_op> m_Shr(const LHS &L,
                                                            const RHS &R) {
    return BinOpPred_match<LHS, RHS, is_right_shift_op>(L, R);
  }
  
  /// Matches logical shift operations.
  template <typename LHS, typename RHS>
  inline BinOpPred_match<LHS, RHS, is_logical_shift_op>
  m_LogicalShift(const LHS &L, const RHS &R) {
    return BinOpPred_match<LHS, RHS, is_logical_shift_op>(L, R);
  }
  
  /// Matches bitwise logic operations.
  template <typename LHS, typename RHS>
  inline BinOpPred_match<LHS, RHS, is_bitwiselogic_op>
  m_BitwiseLogic(const LHS &L, const RHS &R) {
    return BinOpPred_match<LHS, RHS, is_bitwiselogic_op>(L, R);
  }
  
  /// Matches integer division operations.
  template <typename LHS, typename RHS>
  inline BinOpPred_match<LHS, RHS, is_idiv_op> m_IDiv(const LHS &L,
                                                      const RHS &R) {
    return BinOpPred_match<LHS, RHS, is_idiv_op>(L, R);
  }
  
  /// Matches integer remainder operations.
  template <typename LHS, typename RHS>
  inline BinOpPred_match<LHS, RHS, is_irem_op> m_IRem(const LHS &L,
                                                      const RHS &R) {
    return BinOpPred_match<LHS, RHS, is_irem_op>(L, R);
  }
  
  //===----------------------------------------------------------------------===//
  // Class that matches exact binary ops.
  //
  template <typename SubPattern_t> struct Exact_match {
    SubPattern_t SubPattern;
  
    Exact_match(const SubPattern_t &SP) : SubPattern(SP) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *PEO = dyn_cast<PossiblyExactOperator>(V))
        return PEO->isExact() && SubPattern.match(V);
      return false;
    }
  };
  
  template <typename T> inline Exact_match<T> m_Exact(const T &SubPattern) {
    return SubPattern;
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for CmpInst classes
  //
  
  template <typename LHS_t, typename RHS_t, typename Class, typename PredicateTy,
            bool Commutable = false>
  struct CmpClass_match {
    PredicateTy &Predicate;
    LHS_t L;
    RHS_t R;
  
    // The evaluation order is always stable, regardless of Commutability.
    // The LHS is always matched first.
    CmpClass_match(PredicateTy &Pred, const LHS_t &LHS, const RHS_t &RHS)
        : Predicate(Pred), L(LHS), R(RHS) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *I = dyn_cast<Class>(V)) {
        if (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) {
          Predicate = I->getPredicate();
          return true;
        } else if (Commutable && L.match(I->getOperand(1)) &&
             R.match(I->getOperand(0))) {
          Predicate = I->getSwappedPredicate();
          return true;
        }
      }
      return false;
    }
  };
  
  template <typename LHS, typename RHS>
  inline CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>
  m_Cmp(CmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
    return CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>(Pred, L, R);
  }
  
  template <typename LHS, typename RHS>
  inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>
  m_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
    return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>(Pred, L, R);
  }
  
  template <typename LHS, typename RHS>
  inline CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>
  m_FCmp(FCmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
    return CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>(Pred, L, R);
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for instructions with a given opcode and number of operands.
  //
  
  /// Matches instructions with Opcode and three operands.
  template <typename T0, unsigned Opcode> struct OneOps_match {
    T0 Op1;
  
    OneOps_match(const T0 &Op1) : Op1(Op1) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (V->getValueID() == Value::InstructionVal + Opcode) {
        auto *I = cast<Instruction>(V);
        return Op1.match(I->getOperand(0));
      }
      return false;
    }
  };
  
  /// Matches instructions with Opcode and three operands.
  template <typename T0, typename T1, unsigned Opcode> struct TwoOps_match {
    T0 Op1;
    T1 Op2;
  
    TwoOps_match(const T0 &Op1, const T1 &Op2) : Op1(Op1), Op2(Op2) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (V->getValueID() == Value::InstructionVal + Opcode) {
        auto *I = cast<Instruction>(V);
        return Op1.match(I->getOperand(0)) && Op2.match(I->getOperand(1));
      }
      return false;
    }
  };
  
  /// Matches instructions with Opcode and three operands.
  template <typename T0, typename T1, typename T2, unsigned Opcode>
  struct ThreeOps_match {
    T0 Op1;
    T1 Op2;
    T2 Op3;
  
    ThreeOps_match(const T0 &Op1, const T1 &Op2, const T2 &Op3)
        : Op1(Op1), Op2(Op2), Op3(Op3) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (V->getValueID() == Value::InstructionVal + Opcode) {
        auto *I = cast<Instruction>(V);
        return Op1.match(I->getOperand(0)) && Op2.match(I->getOperand(1)) &&
               Op3.match(I->getOperand(2));
      }
      return false;
    }
  };
  
  /// Matches SelectInst.
  template <typename Cond, typename LHS, typename RHS>
  inline ThreeOps_match<Cond, LHS, RHS, Instruction::Select>
  m_Select(const Cond &C, const LHS &L, const RHS &R) {
    return ThreeOps_match<Cond, LHS, RHS, Instruction::Select>(C, L, R);
  }
  
  /// This matches a select of two constants, e.g.:
  /// m_SelectCst<-1, 0>(m_Value(V))
  template <int64_t L, int64_t R, typename Cond>
  inline ThreeOps_match<Cond, constantint_match<L>, constantint_match<R>,
                        Instruction::Select>
  m_SelectCst(const Cond &C) {
    return m_Select(C, m_ConstantInt<L>(), m_ConstantInt<R>());
  }
  
  /// Matches FreezeInst.
  template <typename OpTy>
  inline OneOps_match<OpTy, Instruction::Freeze> m_Freeze(const OpTy &Op) {
    return OneOps_match<OpTy, Instruction::Freeze>(Op);
  }
  
  /// Matches InsertElementInst.
  template <typename Val_t, typename Elt_t, typename Idx_t>
  inline ThreeOps_match<Val_t, Elt_t, Idx_t, Instruction::InsertElement>
  m_InsertElt(const Val_t &Val, const Elt_t &Elt, const Idx_t &Idx) {
    return ThreeOps_match<Val_t, Elt_t, Idx_t, Instruction::InsertElement>(
        Val, Elt, Idx);
  }
  
  /// Matches ExtractElementInst.
  template <typename Val_t, typename Idx_t>
  inline TwoOps_match<Val_t, Idx_t, Instruction::ExtractElement>
  m_ExtractElt(const Val_t &Val, const Idx_t &Idx) {
    return TwoOps_match<Val_t, Idx_t, Instruction::ExtractElement>(Val, Idx);
  }
  
  /// Matches shuffle.
  template <typename T0, typename T1, typename T2> struct Shuffle_match {
    T0 Op1;
    T1 Op2;
    T2 Mask;
  
    Shuffle_match(const T0 &Op1, const T1 &Op2, const T2 &Mask)
        : Op1(Op1), Op2(Op2), Mask(Mask) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *I = dyn_cast<ShuffleVectorInst>(V)) {
        return Op1.match(I->getOperand(0)) && Op2.match(I->getOperand(1)) &&
               Mask.match(I->getShuffleMask());
      }
      return false;
    }
  };
  
  struct m_Mask {
    ArrayRef<int> &MaskRef;
    m_Mask(ArrayRef<int> &MaskRef) : MaskRef(MaskRef) {}
    bool match(ArrayRef<int> Mask) {
      MaskRef = Mask;
      return true;
    }
  };
  
  struct m_ZeroMask {
    bool match(ArrayRef<int> Mask) {
      return all_of(Mask, [](int Elem) { return Elem == 0 || Elem == -1; });
    }
  };
  
  struct m_SpecificMask {
    ArrayRef<int> &MaskRef;
    m_SpecificMask(ArrayRef<int> &MaskRef) : MaskRef(MaskRef) {}
    bool match(ArrayRef<int> Mask) { return MaskRef == Mask; }
  };
  
  struct m_SplatOrUndefMask {
    int &SplatIndex;
    m_SplatOrUndefMask(int &SplatIndex) : SplatIndex(SplatIndex) {}
    bool match(ArrayRef<int> Mask) {
      auto First = find_if(Mask, [](int Elem) { return Elem != -1; });
      if (First == Mask.end())
        return false;
      SplatIndex = *First;
      return all_of(Mask,
                    [First](int Elem) { return Elem == *First || Elem == -1; });
    }
  };
  
  /// Matches ShuffleVectorInst independently of mask value.
  template <typename V1_t, typename V2_t>
  inline TwoOps_match<V1_t, V2_t, Instruction::ShuffleVector>
  m_Shuffle(const V1_t &v1, const V2_t &v2) {
    return TwoOps_match<V1_t, V2_t, Instruction::ShuffleVector>(v1, v2);
  }
  
  template <typename V1_t, typename V2_t, typename Mask_t>
  inline Shuffle_match<V1_t, V2_t, Mask_t>
  m_Shuffle(const V1_t &v1, const V2_t &v2, const Mask_t &mask) {
    return Shuffle_match<V1_t, V2_t, Mask_t>(v1, v2, mask);
  }
  
  /// Matches LoadInst.
  template <typename OpTy>
  inline OneOps_match<OpTy, Instruction::Load> m_Load(const OpTy &Op) {
    return OneOps_match<OpTy, Instruction::Load>(Op);
  }
  
  /// Matches StoreInst.
  template <typename ValueOpTy, typename PointerOpTy>
  inline TwoOps_match<ValueOpTy, PointerOpTy, Instruction::Store>
  m_Store(const ValueOpTy &ValueOp, const PointerOpTy &PointerOp) {
    return TwoOps_match<ValueOpTy, PointerOpTy, Instruction::Store>(ValueOp,
                                                                    PointerOp);
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for CastInst classes
  //
  
  template <typename Op_t, unsigned Opcode> struct CastClass_match {
    Op_t Op;
  
    CastClass_match(const Op_t &OpMatch) : Op(OpMatch) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *O = dyn_cast<Operator>(V))
        return O->getOpcode() == Opcode && Op.match(O->getOperand(0));
      return false;
    }
  };
  
  /// Matches BitCast.
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::BitCast> m_BitCast(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::BitCast>(Op);
  }
  
  /// Matches PtrToInt.
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::PtrToInt> m_PtrToInt(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::PtrToInt>(Op);
  }
  
  /// Matches IntToPtr.
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::IntToPtr> m_IntToPtr(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::IntToPtr>(Op);
  }
  
  /// Matches Trunc.
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::Trunc> m_Trunc(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::Trunc>(Op);
  }
  
  template <typename OpTy>
  inline match_combine_or<CastClass_match<OpTy, Instruction::Trunc>, OpTy>
  m_TruncOrSelf(const OpTy &Op) {
    return m_CombineOr(m_Trunc(Op), Op);
  }
  
  /// Matches SExt.
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::SExt> m_SExt(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::SExt>(Op);
  }
  
  /// Matches ZExt.
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::ZExt> m_ZExt(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::ZExt>(Op);
  }
  
  template <typename OpTy>
  inline match_combine_or<CastClass_match<OpTy, Instruction::ZExt>, OpTy>
  m_ZExtOrSelf(const OpTy &Op) {
    return m_CombineOr(m_ZExt(Op), Op);
  }
  
  template <typename OpTy>
  inline match_combine_or<CastClass_match<OpTy, Instruction::SExt>, OpTy>
  m_SExtOrSelf(const OpTy &Op) {
    return m_CombineOr(m_SExt(Op), Op);
  }
  
  template <typename OpTy>
  inline match_combine_or<CastClass_match<OpTy, Instruction::ZExt>,
                          CastClass_match<OpTy, Instruction::SExt>>
  m_ZExtOrSExt(const OpTy &Op) {
    return m_CombineOr(m_ZExt(Op), m_SExt(Op));
  }
  
  template <typename OpTy>
  inline match_combine_or<
      match_combine_or<CastClass_match<OpTy, Instruction::ZExt>,
                       CastClass_match<OpTy, Instruction::SExt>>,
      OpTy>
  m_ZExtOrSExtOrSelf(const OpTy &Op) {
    return m_CombineOr(m_ZExtOrSExt(Op), Op);
  }
  
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::UIToFP> m_UIToFP(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::UIToFP>(Op);
  }
  
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::SIToFP> m_SIToFP(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::SIToFP>(Op);
  }
  
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::FPToUI> m_FPToUI(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::FPToUI>(Op);
  }
  
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::FPToSI> m_FPToSI(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::FPToSI>(Op);
  }
  
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::FPTrunc> m_FPTrunc(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::FPTrunc>(Op);
  }
  
  template <typename OpTy>
  inline CastClass_match<OpTy, Instruction::FPExt> m_FPExt(const OpTy &Op) {
    return CastClass_match<OpTy, Instruction::FPExt>(Op);
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for control flow.
  //
  
  struct br_match {
    BasicBlock *&Succ;
  
    br_match(BasicBlock *&Succ) : Succ(Succ) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *BI = dyn_cast<BranchInst>(V))
        if (BI->isUnconditional()) {
          Succ = BI->getSuccessor(0);
          return true;
        }
      return false;
    }
  };
  
  inline br_match m_UnconditionalBr(BasicBlock *&Succ) { return br_match(Succ); }
  
  template <typename Cond_t, typename TrueBlock_t, typename FalseBlock_t>
  struct brc_match {
    Cond_t Cond;
    TrueBlock_t T;
    FalseBlock_t F;
  
    brc_match(const Cond_t &C, const TrueBlock_t &t, const FalseBlock_t &f)
        : Cond(C), T(t), F(f) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *BI = dyn_cast<BranchInst>(V))
        if (BI->isConditional() && Cond.match(BI->getCondition()))
          return T.match(BI->getSuccessor(0)) && F.match(BI->getSuccessor(1));
      return false;
    }
  };
  
  template <typename Cond_t>
  inline brc_match<Cond_t, bind_ty<BasicBlock>, bind_ty<BasicBlock>>
  m_Br(const Cond_t &C, BasicBlock *&T, BasicBlock *&F) {
    return brc_match<Cond_t, bind_ty<BasicBlock>, bind_ty<BasicBlock>>(
        C, m_BasicBlock(T), m_BasicBlock(F));
  }
  
  template <typename Cond_t, typename TrueBlock_t, typename FalseBlock_t>
  inline brc_match<Cond_t, TrueBlock_t, FalseBlock_t>
  m_Br(const Cond_t &C, const TrueBlock_t &T, const FalseBlock_t &F) {
    return brc_match<Cond_t, TrueBlock_t, FalseBlock_t>(C, T, F);
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for max/min idioms, eg: "select (sgt x, y), x, y" -> smax(x,y).
  //
  
  template <typename CmpInst_t, typename LHS_t, typename RHS_t, typename Pred_t,
            bool Commutable = false>
  struct MaxMin_match {
    using PredType = Pred_t;
    LHS_t L;
    RHS_t R;
  
    // The evaluation order is always stable, regardless of Commutability.
    // The LHS is always matched first.
    MaxMin_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *II = dyn_cast<IntrinsicInst>(V)) {
        Intrinsic::ID IID = II->getIntrinsicID();
        if ((IID == Intrinsic::smax && Pred_t::match(ICmpInst::ICMP_SGT)) ||
            (IID == Intrinsic::smin && Pred_t::match(ICmpInst::ICMP_SLT)) ||
            (IID == Intrinsic::umax && Pred_t::match(ICmpInst::ICMP_UGT)) ||
            (IID == Intrinsic::umin && Pred_t::match(ICmpInst::ICMP_ULT))) {
          Value *LHS = II->getOperand(0), *RHS = II->getOperand(1);
          return (L.match(LHS) && R.match(RHS)) ||
                 (Commutable && L.match(RHS) && R.match(LHS));
        }
      }
      // Look for "(x pred y) ? x : y" or "(x pred y) ? y : x".
      auto *SI = dyn_cast<SelectInst>(V);
      if (!SI)
        return false;
      auto *Cmp = dyn_cast<CmpInst_t>(SI->getCondition());
      if (!Cmp)
        return false;
      // At this point we have a select conditioned on a comparison.  Check that
      // it is the values returned by the select that are being compared.
      auto *TrueVal = SI->getTrueValue();
      auto *FalseVal = SI->getFalseValue();
      auto *LHS = Cmp->getOperand(0);
      auto *RHS = Cmp->getOperand(1);
      if ((TrueVal != LHS || FalseVal != RHS) &&
          (TrueVal != RHS || FalseVal != LHS))
        return false;
      typename CmpInst_t::Predicate Pred =
          LHS == TrueVal ? Cmp->getPredicate() : Cmp->getInversePredicate();
      // Does "(x pred y) ? x : y" represent the desired max/min operation?
      if (!Pred_t::match(Pred))
        return false;
      // It does!  Bind the operands.
      return (L.match(LHS) && R.match(RHS)) ||
             (Commutable && L.match(RHS) && R.match(LHS));
    }
  };
  
  /// Helper class for identifying signed max predicates.
  struct smax_pred_ty {
    static bool match(ICmpInst::Predicate Pred) {
      return Pred == CmpInst::ICMP_SGT || Pred == CmpInst::ICMP_SGE;
    }
  };
  
  /// Helper class for identifying signed min predicates.
  struct smin_pred_ty {
    static bool match(ICmpInst::Predicate Pred) {
      return Pred == CmpInst::ICMP_SLT || Pred == CmpInst::ICMP_SLE;
    }
  };
  
  /// Helper class for identifying unsigned max predicates.
  struct umax_pred_ty {
    static bool match(ICmpInst::Predicate Pred) {
      return Pred == CmpInst::ICMP_UGT || Pred == CmpInst::ICMP_UGE;
    }
  };
  
  /// Helper class for identifying unsigned min predicates.
  struct umin_pred_ty {
    static bool match(ICmpInst::Predicate Pred) {
      return Pred == CmpInst::ICMP_ULT || Pred == CmpInst::ICMP_ULE;
    }
  };
  
  /// Helper class for identifying ordered max predicates.
  struct ofmax_pred_ty {
    static bool match(FCmpInst::Predicate Pred) {
      return Pred == CmpInst::FCMP_OGT || Pred == CmpInst::FCMP_OGE;
    }
  };
  
  /// Helper class for identifying ordered min predicates.
  struct ofmin_pred_ty {
    static bool match(FCmpInst::Predicate Pred) {
      return Pred == CmpInst::FCMP_OLT || Pred == CmpInst::FCMP_OLE;
    }
  };
  
  /// Helper class for identifying unordered max predicates.
  struct ufmax_pred_ty {
    static bool match(FCmpInst::Predicate Pred) {
      return Pred == CmpInst::FCMP_UGT || Pred == CmpInst::FCMP_UGE;
    }
  };
  
  /// Helper class for identifying unordered min predicates.
  struct ufmin_pred_ty {
    static bool match(FCmpInst::Predicate Pred) {
      return Pred == CmpInst::FCMP_ULT || Pred == CmpInst::FCMP_ULE;
    }
  };
  
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty> m_SMax(const LHS &L,
                                                               const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty> m_SMin(const LHS &L,
                                                               const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty> m_UMax(const LHS &L,
                                                               const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty> m_UMin(const LHS &L,
                                                               const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline match_combine_or<
      match_combine_or<MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty>,
                       MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty>>,
      match_combine_or<MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty>,
                       MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty>>>
  m_MaxOrMin(const LHS &L, const RHS &R) {
    return m_CombineOr(m_CombineOr(m_SMax(L, R), m_SMin(L, R)),
                       m_CombineOr(m_UMax(L, R), m_UMin(L, R)));
  }
  
  /// Match an 'ordered' floating point maximum function.
  /// Floating point has one special value 'NaN'. Therefore, there is no total
  /// order. However, if we can ignore the 'NaN' value (for example, because of a
  /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
  /// semantics. In the presence of 'NaN' we have to preserve the original
  /// select(fcmp(ogt/ge, L, R), L, R) semantics matched by this predicate.
  ///
  ///                         max(L, R)  iff L and R are not NaN
  ///  m_OrdFMax(L, R) =      R          iff L or R are NaN
  template <typename LHS, typename RHS>
  inline MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty> m_OrdFMax(const LHS &L,
                                                                   const RHS &R) {
    return MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty>(L, R);
  }
  
  /// Match an 'ordered' floating point minimum function.
  /// Floating point has one special value 'NaN'. Therefore, there is no total
  /// order. However, if we can ignore the 'NaN' value (for example, because of a
  /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
  /// semantics. In the presence of 'NaN' we have to preserve the original
  /// select(fcmp(olt/le, L, R), L, R) semantics matched by this predicate.
  ///
  ///                         min(L, R)  iff L and R are not NaN
  ///  m_OrdFMin(L, R) =      R          iff L or R are NaN
  template <typename LHS, typename RHS>
  inline MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty> m_OrdFMin(const LHS &L,
                                                                   const RHS &R) {
    return MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty>(L, R);
  }
  
  /// Match an 'unordered' floating point maximum function.
  /// Floating point has one special value 'NaN'. Therefore, there is no total
  /// order. However, if we can ignore the 'NaN' value (for example, because of a
  /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
  /// semantics. In the presence of 'NaN' we have to preserve the original
  /// select(fcmp(ugt/ge, L, R), L, R) semantics matched by this predicate.
  ///
  ///                         max(L, R)  iff L and R are not NaN
  ///  m_UnordFMax(L, R) =    L          iff L or R are NaN
  template <typename LHS, typename RHS>
  inline MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>
  m_UnordFMax(const LHS &L, const RHS &R) {
    return MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>(L, R);
  }
  
  /// Match an 'unordered' floating point minimum function.
  /// Floating point has one special value 'NaN'. Therefore, there is no total
  /// order. However, if we can ignore the 'NaN' value (for example, because of a
  /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
  /// semantics. In the presence of 'NaN' we have to preserve the original
  /// select(fcmp(ult/le, L, R), L, R) semantics matched by this predicate.
  ///
  ///                          min(L, R)  iff L and R are not NaN
  ///  m_UnordFMin(L, R) =     L          iff L or R are NaN
  template <typename LHS, typename RHS>
  inline MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>
  m_UnordFMin(const LHS &L, const RHS &R) {
    return MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>(L, R);
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for overflow check patterns: e.g. (a + b) u< a, (a ^ -1) <u b
  // Note that S might be matched to other instructions than AddInst.
  //
  
  template <typename LHS_t, typename RHS_t, typename Sum_t>
  struct UAddWithOverflow_match {
    LHS_t L;
    RHS_t R;
    Sum_t S;
  
    UAddWithOverflow_match(const LHS_t &L, const RHS_t &R, const Sum_t &S)
        : L(L), R(R), S(S) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      Value *ICmpLHS, *ICmpRHS;
      ICmpInst::Predicate Pred;
      if (!m_ICmp(Pred, m_Value(ICmpLHS), m_Value(ICmpRHS)).match(V))
        return false;
  
      Value *AddLHS, *AddRHS;
      auto AddExpr = m_Add(m_Value(AddLHS), m_Value(AddRHS));
  
      // (a + b) u< a, (a + b) u< b
      if (Pred == ICmpInst::ICMP_ULT)
        if (AddExpr.match(ICmpLHS) && (ICmpRHS == AddLHS || ICmpRHS == AddRHS))
          return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
  
      // a >u (a + b), b >u (a + b)
      if (Pred == ICmpInst::ICMP_UGT)
        if (AddExpr.match(ICmpRHS) && (ICmpLHS == AddLHS || ICmpLHS == AddRHS))
          return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
  
      Value *Op1;
      auto XorExpr = m_OneUse(m_Xor(m_Value(Op1), m_AllOnes()));
      // (a ^ -1) <u b
      if (Pred == ICmpInst::ICMP_ULT) {
        if (XorExpr.match(ICmpLHS))
          return L.match(Op1) && R.match(ICmpRHS) && S.match(ICmpLHS);
      }
      //  b > u (a ^ -1)
      if (Pred == ICmpInst::ICMP_UGT) {
        if (XorExpr.match(ICmpRHS))
          return L.match(Op1) && R.match(ICmpLHS) && S.match(ICmpRHS);
      }
  
      // Match special-case for increment-by-1.
      if (Pred == ICmpInst::ICMP_EQ) {
        // (a + 1) == 0
        // (1 + a) == 0
        if (AddExpr.match(ICmpLHS) && m_ZeroInt().match(ICmpRHS) &&
            (m_One().match(AddLHS) || m_One().match(AddRHS)))
          return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
        // 0 == (a + 1)
        // 0 == (1 + a)
        if (m_ZeroInt().match(ICmpLHS) && AddExpr.match(ICmpRHS) &&
            (m_One().match(AddLHS) || m_One().match(AddRHS)))
          return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
      }
  
      return false;
    }
  };
  
  /// Match an icmp instruction checking for unsigned overflow on addition.
  ///
  /// S is matched to the addition whose result is being checked for overflow, and
  /// L and R are matched to the LHS and RHS of S.
  template <typename LHS_t, typename RHS_t, typename Sum_t>
  UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>
  m_UAddWithOverflow(const LHS_t &L, const RHS_t &R, const Sum_t &S) {
    return UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>(L, R, S);
  }
  
  template <typename Opnd_t> struct Argument_match {
    unsigned OpI;
    Opnd_t Val;
  
    Argument_match(unsigned OpIdx, const Opnd_t &V) : OpI(OpIdx), Val(V) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      // FIXME: Should likely be switched to use `CallBase`.
      if (const auto *CI = dyn_cast<CallInst>(V))
        return Val.match(CI->getArgOperand(OpI));
      return false;
    }
  };
  
  /// Match an argument.
  template <unsigned OpI, typename Opnd_t>
  inline Argument_match<Opnd_t> m_Argument(const Opnd_t &Op) {
    return Argument_match<Opnd_t>(OpI, Op);
  }
  
  /// Intrinsic matchers.
  struct IntrinsicID_match {
    unsigned ID;
  
    IntrinsicID_match(Intrinsic::ID IntrID) : ID(IntrID) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (const auto *CI = dyn_cast<CallInst>(V))
        if (const auto *F = CI->getCalledFunction())
          return F->getIntrinsicID() == ID;
      return false;
    }
  };
  
  /// Intrinsic matches are combinations of ID matchers, and argument
  /// matchers. Higher arity matcher are defined recursively in terms of and-ing
  /// them with lower arity matchers. Here's some convenient typedefs for up to
  /// several arguments, and more can be added as needed
  template <typename T0 = void, typename T1 = void, typename T2 = void,
            typename T3 = void, typename T4 = void, typename T5 = void,
            typename T6 = void, typename T7 = void, typename T8 = void,
            typename T9 = void, typename T10 = void>
  struct m_Intrinsic_Ty;
  template <typename T0> struct m_Intrinsic_Ty<T0> {
    using Ty = match_combine_and<IntrinsicID_match, Argument_match<T0>>;
  };
  template <typename T0, typename T1> struct m_Intrinsic_Ty<T0, T1> {
    using Ty =
        match_combine_and<typename m_Intrinsic_Ty<T0>::Ty, Argument_match<T1>>;
  };
  template <typename T0, typename T1, typename T2>
  struct m_Intrinsic_Ty<T0, T1, T2> {
    using Ty =
        match_combine_and<typename m_Intrinsic_Ty<T0, T1>::Ty,
                          Argument_match<T2>>;
  };
  template <typename T0, typename T1, typename T2, typename T3>
  struct m_Intrinsic_Ty<T0, T1, T2, T3> {
    using Ty =
        match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2>::Ty,
                          Argument_match<T3>>;
  };
  
  template <typename T0, typename T1, typename T2, typename T3, typename T4>
  struct m_Intrinsic_Ty<T0, T1, T2, T3, T4> {
    using Ty = match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2, T3>::Ty,
                                 Argument_match<T4>>;
  };
  
  template <typename T0, typename T1, typename T2, typename T3, typename T4, typename T5>
  struct m_Intrinsic_Ty<T0, T1, T2, T3, T4, T5> {
    using Ty = match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2, T3, T4>::Ty,
                                 Argument_match<T5>>;
  };
  
  /// Match intrinsic calls like this:
  /// m_Intrinsic<Intrinsic::fabs>(m_Value(X))
  template <Intrinsic::ID IntrID> inline IntrinsicID_match m_Intrinsic() {
    return IntrinsicID_match(IntrID);
  }
  
  template <Intrinsic::ID IntrID, typename T0>
  inline typename m_Intrinsic_Ty<T0>::Ty m_Intrinsic(const T0 &Op0) {
    return m_CombineAnd(m_Intrinsic<IntrID>(), m_Argument<0>(Op0));
  }
  
  template <Intrinsic::ID IntrID, typename T0, typename T1>
  inline typename m_Intrinsic_Ty<T0, T1>::Ty m_Intrinsic(const T0 &Op0,
                                                         const T1 &Op1) {
    return m_CombineAnd(m_Intrinsic<IntrID>(Op0), m_Argument<1>(Op1));
  }
  
  template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2>
  inline typename m_Intrinsic_Ty<T0, T1, T2>::Ty
  m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2) {
    return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1), m_Argument<2>(Op2));
  }
  
  template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
            typename T3>
  inline typename m_Intrinsic_Ty<T0, T1, T2, T3>::Ty
  m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3) {
    return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2), m_Argument<3>(Op3));
  }
  
  template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
            typename T3, typename T4>
  inline typename m_Intrinsic_Ty<T0, T1, T2, T3, T4>::Ty
  m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3,
              const T4 &Op4) {
    return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2, Op3),
                        m_Argument<4>(Op4));
  }
  
  template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
            typename T3, typename T4, typename T5>
  inline typename m_Intrinsic_Ty<T0, T1, T2, T3, T4, T5>::Ty
  m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3,
              const T4 &Op4, const T5 &Op5) {
    return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2, Op3, Op4),
                        m_Argument<5>(Op5));
  }
  
  // Helper intrinsic matching specializations.
  template <typename Opnd0>
  inline typename m_Intrinsic_Ty<Opnd0>::Ty m_BitReverse(const Opnd0 &Op0) {
    return m_Intrinsic<Intrinsic::bitreverse>(Op0);
  }
  
  template <typename Opnd0>
  inline typename m_Intrinsic_Ty<Opnd0>::Ty m_BSwap(const Opnd0 &Op0) {
    return m_Intrinsic<Intrinsic::bswap>(Op0);
  }
  
  template <typename Opnd0>
  inline typename m_Intrinsic_Ty<Opnd0>::Ty m_FAbs(const Opnd0 &Op0) {
    return m_Intrinsic<Intrinsic::fabs>(Op0);
  }
  
  template <typename Opnd0>
  inline typename m_Intrinsic_Ty<Opnd0>::Ty m_FCanonicalize(const Opnd0 &Op0) {
    return m_Intrinsic<Intrinsic::canonicalize>(Op0);
  }
  
  template <typename Opnd0, typename Opnd1>
  inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMin(const Opnd0 &Op0,
                                                          const Opnd1 &Op1) {
    return m_Intrinsic<Intrinsic::minnum>(Op0, Op1);
  }
  
  template <typename Opnd0, typename Opnd1>
  inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMax(const Opnd0 &Op0,
                                                          const Opnd1 &Op1) {
    return m_Intrinsic<Intrinsic::maxnum>(Op0, Op1);
  }
  
  template <typename Opnd0, typename Opnd1, typename Opnd2>
  inline typename m_Intrinsic_Ty<Opnd0, Opnd1, Opnd2>::Ty
  m_FShl(const Opnd0 &Op0, const Opnd1 &Op1, const Opnd2 &Op2) {
    return m_Intrinsic<Intrinsic::fshl>(Op0, Op1, Op2);
  }
  
  template <typename Opnd0, typename Opnd1, typename Opnd2>
  inline typename m_Intrinsic_Ty<Opnd0, Opnd1, Opnd2>::Ty
  m_FShr(const Opnd0 &Op0, const Opnd1 &Op1, const Opnd2 &Op2) {
    return m_Intrinsic<Intrinsic::fshr>(Op0, Op1, Op2);
  }
  
  //===----------------------------------------------------------------------===//
  // Matchers for two-operands operators with the operators in either order
  //
  
  /// Matches a BinaryOperator with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline AnyBinaryOp_match<LHS, RHS, true> m_c_BinOp(const LHS &L, const RHS &R) {
    return AnyBinaryOp_match<LHS, RHS, true>(L, R);
  }
  
  /// Matches an ICmp with a predicate over LHS and RHS in either order.
  /// Swaps the predicate if operands are commuted.
  template <typename LHS, typename RHS>
  inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate, true>
  m_c_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
    return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate, true>(Pred, L,
                                                                         R);
  }
  
  /// Matches a Add with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Add, true> m_c_Add(const LHS &L,
                                                                  const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Add, true>(L, R);
  }
  
  /// Matches a Mul with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Mul, true> m_c_Mul(const LHS &L,
                                                                  const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Mul, true>(L, R);
  }
  
  /// Matches an And with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::And, true> m_c_And(const LHS &L,
                                                                  const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::And, true>(L, R);
  }
  
  /// Matches an Or with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Or, true> m_c_Or(const LHS &L,
                                                                const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Or, true>(L, R);
  }
  
  /// Matches an Xor with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::Xor, true> m_c_Xor(const LHS &L,
                                                                  const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::Xor, true>(L, R);
  }
  
  /// Matches a 'Neg' as 'sub 0, V'.
  template <typename ValTy>
  inline BinaryOp_match<cst_pred_ty<is_zero_int>, ValTy, Instruction::Sub>
  m_Neg(const ValTy &V) {
    return m_Sub(m_ZeroInt(), V);
  }
  
  /// Matches a 'Neg' as 'sub nsw 0, V'.
  template <typename ValTy>
  inline OverflowingBinaryOp_match<cst_pred_ty<is_zero_int>, ValTy,
                                   Instruction::Sub,
                                   OverflowingBinaryOperator::NoSignedWrap>
  m_NSWNeg(const ValTy &V) {
    return m_NSWSub(m_ZeroInt(), V);
  }
  
  /// Matches a 'Not' as 'xor V, -1' or 'xor -1, V'.
  template <typename ValTy>
  inline BinaryOp_match<ValTy, cst_pred_ty<is_all_ones>, Instruction::Xor, true>
  m_Not(const ValTy &V) {
    return m_c_Xor(V, m_AllOnes());
  }
  
  /// Matches an SMin with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty, true>
  m_c_SMin(const LHS &L, const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty, true>(L, R);
  }
  /// Matches an SMax with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty, true>
  m_c_SMax(const LHS &L, const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty, true>(L, R);
  }
  /// Matches a UMin with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty, true>
  m_c_UMin(const LHS &L, const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty, true>(L, R);
  }
  /// Matches a UMax with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty, true>
  m_c_UMax(const LHS &L, const RHS &R) {
    return MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty, true>(L, R);
  }
  
  template <typename LHS, typename RHS>
  inline match_combine_or<
      match_combine_or<MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty, true>,
                       MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty, true>>,
      match_combine_or<MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty, true>,
                       MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty, true>>>
  m_c_MaxOrMin(const LHS &L, const RHS &R) {
    return m_CombineOr(m_CombineOr(m_c_SMax(L, R), m_c_SMin(L, R)),
                       m_CombineOr(m_c_UMax(L, R), m_c_UMin(L, R)));
  }
  
  /// Matches FAdd with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::FAdd, true>
  m_c_FAdd(const LHS &L, const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::FAdd, true>(L, R);
  }
  
  /// Matches FMul with LHS and RHS in either order.
  template <typename LHS, typename RHS>
  inline BinaryOp_match<LHS, RHS, Instruction::FMul, true>
  m_c_FMul(const LHS &L, const RHS &R) {
    return BinaryOp_match<LHS, RHS, Instruction::FMul, true>(L, R);
  }
  
  template <typename Opnd_t> struct Signum_match {
    Opnd_t Val;
    Signum_match(const Opnd_t &V) : Val(V) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      unsigned TypeSize = V->getType()->getScalarSizeInBits();
      if (TypeSize == 0)
        return false;
  
      unsigned ShiftWidth = TypeSize - 1;
      Value *OpL = nullptr, *OpR = nullptr;
  
      // This is the representation of signum we match:
      //
      //  signum(x) == (x >> 63) | (-x >>u 63)
      //
      // An i1 value is its own signum, so it's correct to match
      //
      //  signum(x) == (x >> 0)  | (-x >>u 0)
      //
      // for i1 values.
  
      auto LHS = m_AShr(m_Value(OpL), m_SpecificInt(ShiftWidth));
      auto RHS = m_LShr(m_Neg(m_Value(OpR)), m_SpecificInt(ShiftWidth));
      auto Signum = m_Or(LHS, RHS);
  
      return Signum.match(V) && OpL == OpR && Val.match(OpL);
    }
  };
  
  /// Matches a signum pattern.
  ///
  /// signum(x) =
  ///      x >  0  ->  1
  ///      x == 0  ->  0
  ///      x <  0  -> -1
  template <typename Val_t> inline Signum_match<Val_t> m_Signum(const Val_t &V) {
    return Signum_match<Val_t>(V);
  }
  
  template <int Ind, typename Opnd_t> struct ExtractValue_match {
    Opnd_t Val;
    ExtractValue_match(const Opnd_t &V) : Val(V) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *I = dyn_cast<ExtractValueInst>(V)) {
        // If Ind is -1, don't inspect indices
        if (Ind != -1 &&
            !(I->getNumIndices() == 1 && I->getIndices()[0] == (unsigned)Ind))
          return false;
        return Val.match(I->getAggregateOperand());
      }
      return false;
    }
  };
  
  /// Match a single index ExtractValue instruction.
  /// For example m_ExtractValue<1>(...)
  template <int Ind, typename Val_t>
  inline ExtractValue_match<Ind, Val_t> m_ExtractValue(const Val_t &V) {
    return ExtractValue_match<Ind, Val_t>(V);
  }
  
  /// Match an ExtractValue instruction with any index.
  /// For example m_ExtractValue(...)
  template <typename Val_t>
  inline ExtractValue_match<-1, Val_t> m_ExtractValue(const Val_t &V) {
    return ExtractValue_match<-1, Val_t>(V);
  }
  
  /// Matcher for a single index InsertValue instruction.
  template <int Ind, typename T0, typename T1> struct InsertValue_match {
    T0 Op0;
    T1 Op1;
  
    InsertValue_match(const T0 &Op0, const T1 &Op1) : Op0(Op0), Op1(Op1) {}
  
    template <typename OpTy> bool match(OpTy *V) {
      if (auto *I = dyn_cast<InsertValueInst>(V)) {
        return Op0.match(I->getOperand(0)) && Op1.match(I->getOperand(1)) &&
               I->getNumIndices() == 1 && Ind == I->getIndices()[0];
      }
      return false;
    }
  };
  
  /// Matches a single index InsertValue instruction.
  template <int Ind, typename Val_t, typename Elt_t>
  inline InsertValue_match<Ind, Val_t, Elt_t> m_InsertValue(const Val_t &Val,
                                                            const Elt_t &Elt) {
    return InsertValue_match<Ind, Val_t, Elt_t>(Val, Elt);
  }
  
  /// Matches patterns for `vscale`. This can either be a call to `llvm.vscale` or
  /// the constant expression
  ///  `ptrtoint(gep <vscale x 1 x i8>, <vscale x 1 x i8>* null, i32 1>`
  /// under the right conditions determined by DataLayout.
  struct VScaleVal_match {
  private:
    template <typename Base, typename Offset>
    inline BinaryOp_match<Base, Offset, Instruction::GetElementPtr>
    m_OffsetGep(const Base &B, const Offset &O) {
      return BinaryOp_match<Base, Offset, Instruction::GetElementPtr>(B, O);
    }
  
  public:
    const DataLayout &DL;
    VScaleVal_match(const DataLayout &DL) : DL(DL) {}
  
    template <typename ITy> bool match(ITy *V) {
      if (m_Intrinsic<Intrinsic::vscale>().match(V))
        return true;
  
      if (m_PtrToInt(m_OffsetGep(m_Zero(), m_SpecificInt(1))).match(V)) {
        Type *PtrTy = cast<Operator>(V)->getOperand(0)->getType();
        auto *DerefTy = PtrTy->getPointerElementType();
        if (isa<ScalableVectorType>(DerefTy) &&
            DL.getTypeAllocSizeInBits(DerefTy).getKnownMinSize() == 8)
          return true;
      }
  
      return false;
    }
  };
  
  inline VScaleVal_match m_VScale(const DataLayout &DL) {
    return VScaleVal_match(DL);
  }
  
  template <typename LHS, typename RHS, unsigned Opcode>
  struct LogicalOp_match {
    LHS L;
    RHS R;
  
    LogicalOp_match(const LHS &L, const RHS &R) : L(L), R(R) {}
  
    template <typename T> bool match(T *V) {
      if (auto *I = dyn_cast<Instruction>(V)) {
        if (!I->getType()->isIntOrIntVectorTy(1))
          return false;
  
        if (I->getOpcode() == Opcode && L.match(I->getOperand(0)) &&
            R.match(I->getOperand(1)))
          return true;
  
        if (auto *SI = dyn_cast<SelectInst>(I)) {
          if (Opcode == Instruction::And) {
            if (const auto *C = dyn_cast<Constant>(SI->getFalseValue()))
              if (C->isNullValue() && L.match(SI->getCondition()) &&
                  R.match(SI->getTrueValue()))
                return true;
          } else {
            assert(Opcode == Instruction::Or);
            if (const auto *C = dyn_cast<Constant>(SI->getTrueValue()))
              if (C->isOneValue() && L.match(SI->getCondition()) &&
                  R.match(SI->getFalseValue()))
                return true;
          }
        }
      }
  
      return false;
    }
  };
  
  /// Matches L && R either in the form of L & R or L ? R : false.
  /// Note that the latter form is poison-blocking.
  template <typename LHS, typename RHS>
  inline LogicalOp_match<LHS, RHS, Instruction::And>
  m_LogicalAnd(const LHS &L, const RHS &R) {
    return LogicalOp_match<LHS, RHS, Instruction::And>(L, R);
  }
  
  /// Matches L && R where L and R are arbitrary values.
  inline auto m_LogicalAnd() { return m_LogicalAnd(m_Value(), m_Value()); }
  
  /// Matches L || R either in the form of L | R or L ? true : R.
  /// Note that the latter form is poison-blocking.
  template <typename LHS, typename RHS>
  inline LogicalOp_match<LHS, RHS, Instruction::Or>
  m_LogicalOr(const LHS &L, const RHS &R) {
    return LogicalOp_match<LHS, RHS, Instruction::Or>(L, R);
  }
  
  /// Matches L || R where L and R are arbitrary values.
  inline auto m_LogicalOr() {
    return m_LogicalOr(m_Value(), m_Value());
  }
  
  } // end namespace PatternMatch
  } // end namespace llvm
  
  #endif // LLVM_IR_PATTERNMATCH_H
  