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      1 //===- PatternMatch.h - Match on the LLVM IR --------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file provides a simple and efficient mechanism for performing general
     11 // tree-based pattern matches on the LLVM IR.  The power of these routines is
     12 // that it allows you to write concise patterns that are expressive and easy to
     13 // understand.  The other major advantage of this is that it allows you to
     14 // trivially capture/bind elements in the pattern to variables.  For example,
     15 // you can do something like this:
     16 //
     17 //  Value *Exp = ...
     18 //  Value *X, *Y;  ConstantInt *C1, *C2;      // (X & C1) | (Y & C2)
     19 //  if (match(Exp, m_Or(m_And(m_Value(X), m_ConstantInt(C1)),
     20 //                      m_And(m_Value(Y), m_ConstantInt(C2))))) {
     21 //    ... Pattern is matched and variables are bound ...
     22 //  }
     23 //
     24 // This is primarily useful to things like the instruction combiner, but can
     25 // also be useful for static analysis tools or code generators.
     26 //
     27 //===----------------------------------------------------------------------===//
     28 
     29 #ifndef LLVM_IR_PATTERNMATCH_H
     30 #define LLVM_IR_PATTERNMATCH_H
     31 
     32 #include "llvm/IR/CallSite.h"
     33 #include "llvm/IR/Constants.h"
     34 #include "llvm/IR/Instructions.h"
     35 #include "llvm/IR/Intrinsics.h"
     36 #include "llvm/IR/Operator.h"
     37 
     38 namespace llvm {
     39 namespace PatternMatch {
     40 
     41 template <typename Val, typename Pattern> bool match(Val *V, const Pattern &P) {
     42   return const_cast<Pattern &>(P).match(V);
     43 }
     44 
     45 template <typename SubPattern_t> struct OneUse_match {
     46   SubPattern_t SubPattern;
     47 
     48   OneUse_match(const SubPattern_t &SP) : SubPattern(SP) {}
     49 
     50   template <typename OpTy> bool match(OpTy *V) {
     51     return V->hasOneUse() && SubPattern.match(V);
     52   }
     53 };
     54 
     55 template <typename T> inline OneUse_match<T> m_OneUse(const T &SubPattern) {
     56   return SubPattern;
     57 }
     58 
     59 template <typename Class> struct class_match {
     60   template <typename ITy> bool match(ITy *V) { return isa<Class>(V); }
     61 };
     62 
     63 /// \brief Match an arbitrary value and ignore it.
     64 inline class_match<Value> m_Value() { return class_match<Value>(); }
     65 
     66 /// \brief Match an arbitrary binary operation and ignore it.
     67 inline class_match<BinaryOperator> m_BinOp() {
     68   return class_match<BinaryOperator>();
     69 }
     70 
     71 /// \brief Matches any compare instruction and ignore it.
     72 inline class_match<CmpInst> m_Cmp() { return class_match<CmpInst>(); }
     73 
     74 /// \brief Match an arbitrary ConstantInt and ignore it.
     75 inline class_match<ConstantInt> m_ConstantInt() {
     76   return class_match<ConstantInt>();
     77 }
     78 
     79 /// \brief Match an arbitrary undef constant.
     80 inline class_match<UndefValue> m_Undef() { return class_match<UndefValue>(); }
     81 
     82 /// \brief Match an arbitrary Constant and ignore it.
     83 inline class_match<Constant> m_Constant() { return class_match<Constant>(); }
     84 
     85 /// Matching combinators
     86 template <typename LTy, typename RTy> struct match_combine_or {
     87   LTy L;
     88   RTy R;
     89 
     90   match_combine_or(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
     91 
     92   template <typename ITy> bool match(ITy *V) {
     93     if (L.match(V))
     94       return true;
     95     if (R.match(V))
     96       return true;
     97     return false;
     98   }
     99 };
    100 
    101 template <typename LTy, typename RTy> struct match_combine_and {
    102   LTy L;
    103   RTy R;
    104 
    105   match_combine_and(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
    106 
    107   template <typename ITy> bool match(ITy *V) {
    108     if (L.match(V))
    109       if (R.match(V))
    110         return true;
    111     return false;
    112   }
    113 };
    114 
    115 /// Combine two pattern matchers matching L || R
    116 template <typename LTy, typename RTy>
    117 inline match_combine_or<LTy, RTy> m_CombineOr(const LTy &L, const RTy &R) {
    118   return match_combine_or<LTy, RTy>(L, R);
    119 }
    120 
    121 /// Combine two pattern matchers matching L && R
    122 template <typename LTy, typename RTy>
    123 inline match_combine_and<LTy, RTy> m_CombineAnd(const LTy &L, const RTy &R) {
    124   return match_combine_and<LTy, RTy>(L, R);
    125 }
    126 
    127 struct match_zero {
    128   template <typename ITy> bool match(ITy *V) {
    129     if (const auto *C = dyn_cast<Constant>(V))
    130       return C->isNullValue();
    131     return false;
    132   }
    133 };
    134 
    135 /// \brief Match an arbitrary zero/null constant.  This includes
    136 /// zero_initializer for vectors and ConstantPointerNull for pointers.
    137 inline match_zero m_Zero() { return match_zero(); }
    138 
    139 struct match_neg_zero {
    140   template <typename ITy> bool match(ITy *V) {
    141     if (const auto *C = dyn_cast<Constant>(V))
    142       return C->isNegativeZeroValue();
    143     return false;
    144   }
    145 };
    146 
    147 /// \brief Match an arbitrary zero/null constant.  This includes
    148 /// zero_initializer for vectors and ConstantPointerNull for pointers. For
    149 /// floating point constants, this will match negative zero but not positive
    150 /// zero
    151 inline match_neg_zero m_NegZero() { return match_neg_zero(); }
    152 
    153 /// \brief - Match an arbitrary zero/null constant.  This includes
    154 /// zero_initializer for vectors and ConstantPointerNull for pointers. For
    155 /// floating point constants, this will match negative zero and positive zero
    156 inline match_combine_or<match_zero, match_neg_zero> m_AnyZero() {
    157   return m_CombineOr(m_Zero(), m_NegZero());
    158 }
    159 
    160 struct apint_match {
    161   const APInt *&Res;
    162   apint_match(const APInt *&R) : Res(R) {}
    163   template <typename ITy> bool match(ITy *V) {
    164     if (auto *CI = dyn_cast<ConstantInt>(V)) {
    165       Res = &CI->getValue();
    166       return true;
    167     }
    168     if (V->getType()->isVectorTy())
    169       if (const auto *C = dyn_cast<Constant>(V))
    170         if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue())) {
    171           Res = &CI->getValue();
    172           return true;
    173         }
    174     return false;
    175   }
    176 };
    177 
    178 /// \brief Match a ConstantInt or splatted ConstantVector, binding the
    179 /// specified pointer to the contained APInt.
    180 inline apint_match m_APInt(const APInt *&Res) { return Res; }
    181 
    182 template <int64_t Val> struct constantint_match {
    183   template <typename ITy> bool match(ITy *V) {
    184     if (const auto *CI = dyn_cast<ConstantInt>(V)) {
    185       const APInt &CIV = CI->getValue();
    186       if (Val >= 0)
    187         return CIV == static_cast<uint64_t>(Val);
    188       // If Val is negative, and CI is shorter than it, truncate to the right
    189       // number of bits.  If it is larger, then we have to sign extend.  Just
    190       // compare their negated values.
    191       return -CIV == -Val;
    192     }
    193     return false;
    194   }
    195 };
    196 
    197 /// \brief Match a ConstantInt with a specific value.
    198 template <int64_t Val> inline constantint_match<Val> m_ConstantInt() {
    199   return constantint_match<Val>();
    200 }
    201 
    202 /// \brief This helper class is used to match scalar and vector constants that
    203 /// satisfy a specified predicate.
    204 template <typename Predicate> struct cst_pred_ty : public Predicate {
    205   template <typename ITy> bool match(ITy *V) {
    206     if (const auto *CI = dyn_cast<ConstantInt>(V))
    207       return this->isValue(CI->getValue());
    208     if (V->getType()->isVectorTy())
    209       if (const auto *C = dyn_cast<Constant>(V))
    210         if (const auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
    211           return this->isValue(CI->getValue());
    212     return false;
    213   }
    214 };
    215 
    216 /// \brief This helper class is used to match scalar and vector constants that
    217 /// satisfy a specified predicate, and bind them to an APInt.
    218 template <typename Predicate> struct api_pred_ty : public Predicate {
    219   const APInt *&Res;
    220   api_pred_ty(const APInt *&R) : Res(R) {}
    221   template <typename ITy> bool match(ITy *V) {
    222     if (const auto *CI = dyn_cast<ConstantInt>(V))
    223       if (this->isValue(CI->getValue())) {
    224         Res = &CI->getValue();
    225         return true;
    226       }
    227     if (V->getType()->isVectorTy())
    228       if (const auto *C = dyn_cast<Constant>(V))
    229         if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
    230           if (this->isValue(CI->getValue())) {
    231             Res = &CI->getValue();
    232             return true;
    233           }
    234 
    235     return false;
    236   }
    237 };
    238 
    239 struct is_one {
    240   bool isValue(const APInt &C) { return C == 1; }
    241 };
    242 
    243 /// \brief Match an integer 1 or a vector with all elements equal to 1.
    244 inline cst_pred_ty<is_one> m_One() { return cst_pred_ty<is_one>(); }
    245 inline api_pred_ty<is_one> m_One(const APInt *&V) { return V; }
    246 
    247 struct is_all_ones {
    248   bool isValue(const APInt &C) { return C.isAllOnesValue(); }
    249 };
    250 
    251 /// \brief Match an integer or vector with all bits set to true.
    252 inline cst_pred_ty<is_all_ones> m_AllOnes() {
    253   return cst_pred_ty<is_all_ones>();
    254 }
    255 inline api_pred_ty<is_all_ones> m_AllOnes(const APInt *&V) { return V; }
    256 
    257 struct is_sign_bit {
    258   bool isValue(const APInt &C) { return C.isSignBit(); }
    259 };
    260 
    261 /// \brief Match an integer or vector with only the sign bit(s) set.
    262 inline cst_pred_ty<is_sign_bit> m_SignBit() {
    263   return cst_pred_ty<is_sign_bit>();
    264 }
    265 inline api_pred_ty<is_sign_bit> m_SignBit(const APInt *&V) { return V; }
    266 
    267 struct is_power2 {
    268   bool isValue(const APInt &C) { return C.isPowerOf2(); }
    269 };
    270 
    271 /// \brief Match an integer or vector power of 2.
    272 inline cst_pred_ty<is_power2> m_Power2() { return cst_pred_ty<is_power2>(); }
    273 inline api_pred_ty<is_power2> m_Power2(const APInt *&V) { return V; }
    274 
    275 struct is_maxsignedvalue {
    276   bool isValue(const APInt &C) { return C.isMaxSignedValue(); }
    277 };
    278 
    279 inline cst_pred_ty<is_maxsignedvalue> m_MaxSignedValue() { return cst_pred_ty<is_maxsignedvalue>(); }
    280 inline api_pred_ty<is_maxsignedvalue> m_MaxSignedValue(const APInt *&V) { return V; }
    281 
    282 template <typename Class> struct bind_ty {
    283   Class *&VR;
    284   bind_ty(Class *&V) : VR(V) {}
    285 
    286   template <typename ITy> bool match(ITy *V) {
    287     if (auto *CV = dyn_cast<Class>(V)) {
    288       VR = CV;
    289       return true;
    290     }
    291     return false;
    292   }
    293 };
    294 
    295 /// \brief Match a value, capturing it if we match.
    296 inline bind_ty<Value> m_Value(Value *&V) { return V; }
    297 
    298 /// \brief Match an instruction, capturing it if we match.
    299 inline bind_ty<Instruction> m_Instruction(Instruction *&I) { return I; }
    300 
    301 /// \brief Match a binary operator, capturing it if we match.
    302 inline bind_ty<BinaryOperator> m_BinOp(BinaryOperator *&I) { return I; }
    303 
    304 /// \brief Match a ConstantInt, capturing the value if we match.
    305 inline bind_ty<ConstantInt> m_ConstantInt(ConstantInt *&CI) { return CI; }
    306 
    307 /// \brief Match a Constant, capturing the value if we match.
    308 inline bind_ty<Constant> m_Constant(Constant *&C) { return C; }
    309 
    310 /// \brief Match a ConstantFP, capturing the value if we match.
    311 inline bind_ty<ConstantFP> m_ConstantFP(ConstantFP *&C) { return C; }
    312 
    313 /// \brief Match a specified Value*.
    314 struct specificval_ty {
    315   const Value *Val;
    316   specificval_ty(const Value *V) : Val(V) {}
    317 
    318   template <typename ITy> bool match(ITy *V) { return V == Val; }
    319 };
    320 
    321 /// \brief Match if we have a specific specified value.
    322 inline specificval_ty m_Specific(const Value *V) { return V; }
    323 
    324 /// \brief Match a specified floating point value or vector of all elements of
    325 /// that value.
    326 struct specific_fpval {
    327   double Val;
    328   specific_fpval(double V) : Val(V) {}
    329 
    330   template <typename ITy> bool match(ITy *V) {
    331     if (const auto *CFP = dyn_cast<ConstantFP>(V))
    332       return CFP->isExactlyValue(Val);
    333     if (V->getType()->isVectorTy())
    334       if (const auto *C = dyn_cast<Constant>(V))
    335         if (auto *CFP = dyn_cast_or_null<ConstantFP>(C->getSplatValue()))
    336           return CFP->isExactlyValue(Val);
    337     return false;
    338   }
    339 };
    340 
    341 /// \brief Match a specific floating point value or vector with all elements
    342 /// equal to the value.
    343 inline specific_fpval m_SpecificFP(double V) { return specific_fpval(V); }
    344 
    345 /// \brief Match a float 1.0 or vector with all elements equal to 1.0.
    346 inline specific_fpval m_FPOne() { return m_SpecificFP(1.0); }
    347 
    348 struct bind_const_intval_ty {
    349   uint64_t &VR;
    350   bind_const_intval_ty(uint64_t &V) : VR(V) {}
    351 
    352   template <typename ITy> bool match(ITy *V) {
    353     if (const auto *CV = dyn_cast<ConstantInt>(V))
    354       if (CV->getBitWidth() <= 64) {
    355         VR = CV->getZExtValue();
    356         return true;
    357       }
    358     return false;
    359   }
    360 };
    361 
    362 /// \brief Match a specified integer value or vector of all elements of that
    363 // value.
    364 struct specific_intval {
    365   uint64_t Val;
    366   specific_intval(uint64_t V) : Val(V) {}
    367 
    368   template <typename ITy> bool match(ITy *V) {
    369     const auto *CI = dyn_cast<ConstantInt>(V);
    370     if (!CI && V->getType()->isVectorTy())
    371       if (const auto *C = dyn_cast<Constant>(V))
    372         CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue());
    373 
    374     if (CI && CI->getBitWidth() <= 64)
    375       return CI->getZExtValue() == Val;
    376 
    377     return false;
    378   }
    379 };
    380 
    381 /// \brief Match a specific integer value or vector with all elements equal to
    382 /// the value.
    383 inline specific_intval m_SpecificInt(uint64_t V) { return specific_intval(V); }
    384 
    385 /// \brief Match a ConstantInt and bind to its value.  This does not match
    386 /// ConstantInts wider than 64-bits.
    387 inline bind_const_intval_ty m_ConstantInt(uint64_t &V) { return V; }
    388 
    389 //===----------------------------------------------------------------------===//
    390 // Matcher for any binary operator.
    391 //
    392 template <typename LHS_t, typename RHS_t> struct AnyBinaryOp_match {
    393   LHS_t L;
    394   RHS_t R;
    395 
    396   AnyBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
    397 
    398   template <typename OpTy> bool match(OpTy *V) {
    399     if (auto *I = dyn_cast<BinaryOperator>(V))
    400       return L.match(I->getOperand(0)) && R.match(I->getOperand(1));
    401     return false;
    402   }
    403 };
    404 
    405 template <typename LHS, typename RHS>
    406 inline AnyBinaryOp_match<LHS, RHS> m_BinOp(const LHS &L, const RHS &R) {
    407   return AnyBinaryOp_match<LHS, RHS>(L, R);
    408 }
    409 
    410 //===----------------------------------------------------------------------===//
    411 // Matchers for specific binary operators.
    412 //
    413 
    414 template <typename LHS_t, typename RHS_t, unsigned Opcode>
    415 struct BinaryOp_match {
    416   LHS_t L;
    417   RHS_t R;
    418 
    419   BinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
    420 
    421   template <typename OpTy> bool match(OpTy *V) {
    422     if (V->getValueID() == Value::InstructionVal + Opcode) {
    423       auto *I = cast<BinaryOperator>(V);
    424       return L.match(I->getOperand(0)) && R.match(I->getOperand(1));
    425     }
    426     if (auto *CE = dyn_cast<ConstantExpr>(V))
    427       return CE->getOpcode() == Opcode && L.match(CE->getOperand(0)) &&
    428              R.match(CE->getOperand(1));
    429     return false;
    430   }
    431 };
    432 
    433 template <typename LHS, typename RHS>
    434 inline BinaryOp_match<LHS, RHS, Instruction::Add> m_Add(const LHS &L,
    435                                                         const RHS &R) {
    436   return BinaryOp_match<LHS, RHS, Instruction::Add>(L, R);
    437 }
    438 
    439 template <typename LHS, typename RHS>
    440 inline BinaryOp_match<LHS, RHS, Instruction::FAdd> m_FAdd(const LHS &L,
    441                                                           const RHS &R) {
    442   return BinaryOp_match<LHS, RHS, Instruction::FAdd>(L, R);
    443 }
    444 
    445 template <typename LHS, typename RHS>
    446 inline BinaryOp_match<LHS, RHS, Instruction::Sub> m_Sub(const LHS &L,
    447                                                         const RHS &R) {
    448   return BinaryOp_match<LHS, RHS, Instruction::Sub>(L, R);
    449 }
    450 
    451 template <typename LHS, typename RHS>
    452 inline BinaryOp_match<LHS, RHS, Instruction::FSub> m_FSub(const LHS &L,
    453                                                           const RHS &R) {
    454   return BinaryOp_match<LHS, RHS, Instruction::FSub>(L, R);
    455 }
    456 
    457 template <typename LHS, typename RHS>
    458 inline BinaryOp_match<LHS, RHS, Instruction::Mul> m_Mul(const LHS &L,
    459                                                         const RHS &R) {
    460   return BinaryOp_match<LHS, RHS, Instruction::Mul>(L, R);
    461 }
    462 
    463 template <typename LHS, typename RHS>
    464 inline BinaryOp_match<LHS, RHS, Instruction::FMul> m_FMul(const LHS &L,
    465                                                           const RHS &R) {
    466   return BinaryOp_match<LHS, RHS, Instruction::FMul>(L, R);
    467 }
    468 
    469 template <typename LHS, typename RHS>
    470 inline BinaryOp_match<LHS, RHS, Instruction::UDiv> m_UDiv(const LHS &L,
    471                                                           const RHS &R) {
    472   return BinaryOp_match<LHS, RHS, Instruction::UDiv>(L, R);
    473 }
    474 
    475 template <typename LHS, typename RHS>
    476 inline BinaryOp_match<LHS, RHS, Instruction::SDiv> m_SDiv(const LHS &L,
    477                                                           const RHS &R) {
    478   return BinaryOp_match<LHS, RHS, Instruction::SDiv>(L, R);
    479 }
    480 
    481 template <typename LHS, typename RHS>
    482 inline BinaryOp_match<LHS, RHS, Instruction::FDiv> m_FDiv(const LHS &L,
    483                                                           const RHS &R) {
    484   return BinaryOp_match<LHS, RHS, Instruction::FDiv>(L, R);
    485 }
    486 
    487 template <typename LHS, typename RHS>
    488 inline BinaryOp_match<LHS, RHS, Instruction::URem> m_URem(const LHS &L,
    489                                                           const RHS &R) {
    490   return BinaryOp_match<LHS, RHS, Instruction::URem>(L, R);
    491 }
    492 
    493 template <typename LHS, typename RHS>
    494 inline BinaryOp_match<LHS, RHS, Instruction::SRem> m_SRem(const LHS &L,
    495                                                           const RHS &R) {
    496   return BinaryOp_match<LHS, RHS, Instruction::SRem>(L, R);
    497 }
    498 
    499 template <typename LHS, typename RHS>
    500 inline BinaryOp_match<LHS, RHS, Instruction::FRem> m_FRem(const LHS &L,
    501                                                           const RHS &R) {
    502   return BinaryOp_match<LHS, RHS, Instruction::FRem>(L, R);
    503 }
    504 
    505 template <typename LHS, typename RHS>
    506 inline BinaryOp_match<LHS, RHS, Instruction::And> m_And(const LHS &L,
    507                                                         const RHS &R) {
    508   return BinaryOp_match<LHS, RHS, Instruction::And>(L, R);
    509 }
    510 
    511 template <typename LHS, typename RHS>
    512 inline BinaryOp_match<LHS, RHS, Instruction::Or> m_Or(const LHS &L,
    513                                                       const RHS &R) {
    514   return BinaryOp_match<LHS, RHS, Instruction::Or>(L, R);
    515 }
    516 
    517 template <typename LHS, typename RHS>
    518 inline BinaryOp_match<LHS, RHS, Instruction::Xor> m_Xor(const LHS &L,
    519                                                         const RHS &R) {
    520   return BinaryOp_match<LHS, RHS, Instruction::Xor>(L, R);
    521 }
    522 
    523 template <typename LHS, typename RHS>
    524 inline BinaryOp_match<LHS, RHS, Instruction::Shl> m_Shl(const LHS &L,
    525                                                         const RHS &R) {
    526   return BinaryOp_match<LHS, RHS, Instruction::Shl>(L, R);
    527 }
    528 
    529 template <typename LHS, typename RHS>
    530 inline BinaryOp_match<LHS, RHS, Instruction::LShr> m_LShr(const LHS &L,
    531                                                           const RHS &R) {
    532   return BinaryOp_match<LHS, RHS, Instruction::LShr>(L, R);
    533 }
    534 
    535 template <typename LHS, typename RHS>
    536 inline BinaryOp_match<LHS, RHS, Instruction::AShr> m_AShr(const LHS &L,
    537                                                           const RHS &R) {
    538   return BinaryOp_match<LHS, RHS, Instruction::AShr>(L, R);
    539 }
    540 
    541 template <typename LHS_t, typename RHS_t, unsigned Opcode,
    542           unsigned WrapFlags = 0>
    543 struct OverflowingBinaryOp_match {
    544   LHS_t L;
    545   RHS_t R;
    546 
    547   OverflowingBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS)
    548       : L(LHS), R(RHS) {}
    549 
    550   template <typename OpTy> bool match(OpTy *V) {
    551     if (auto *Op = dyn_cast<OverflowingBinaryOperator>(V)) {
    552       if (Op->getOpcode() != Opcode)
    553         return false;
    554       if (WrapFlags & OverflowingBinaryOperator::NoUnsignedWrap &&
    555           !Op->hasNoUnsignedWrap())
    556         return false;
    557       if (WrapFlags & OverflowingBinaryOperator::NoSignedWrap &&
    558           !Op->hasNoSignedWrap())
    559         return false;
    560       return L.match(Op->getOperand(0)) && R.match(Op->getOperand(1));
    561     }
    562     return false;
    563   }
    564 };
    565 
    566 template <typename LHS, typename RHS>
    567 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
    568                                  OverflowingBinaryOperator::NoSignedWrap>
    569 m_NSWAdd(const LHS &L, const RHS &R) {
    570   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
    571                                    OverflowingBinaryOperator::NoSignedWrap>(
    572       L, R);
    573 }
    574 template <typename LHS, typename RHS>
    575 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
    576                                  OverflowingBinaryOperator::NoSignedWrap>
    577 m_NSWSub(const LHS &L, const RHS &R) {
    578   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
    579                                    OverflowingBinaryOperator::NoSignedWrap>(
    580       L, R);
    581 }
    582 template <typename LHS, typename RHS>
    583 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
    584                                  OverflowingBinaryOperator::NoSignedWrap>
    585 m_NSWMul(const LHS &L, const RHS &R) {
    586   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
    587                                    OverflowingBinaryOperator::NoSignedWrap>(
    588       L, R);
    589 }
    590 template <typename LHS, typename RHS>
    591 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
    592                                  OverflowingBinaryOperator::NoSignedWrap>
    593 m_NSWShl(const LHS &L, const RHS &R) {
    594   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
    595                                    OverflowingBinaryOperator::NoSignedWrap>(
    596       L, R);
    597 }
    598 
    599 template <typename LHS, typename RHS>
    600 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
    601                                  OverflowingBinaryOperator::NoUnsignedWrap>
    602 m_NUWAdd(const LHS &L, const RHS &R) {
    603   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
    604                                    OverflowingBinaryOperator::NoUnsignedWrap>(
    605       L, R);
    606 }
    607 template <typename LHS, typename RHS>
    608 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
    609                                  OverflowingBinaryOperator::NoUnsignedWrap>
    610 m_NUWSub(const LHS &L, const RHS &R) {
    611   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
    612                                    OverflowingBinaryOperator::NoUnsignedWrap>(
    613       L, R);
    614 }
    615 template <typename LHS, typename RHS>
    616 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
    617                                  OverflowingBinaryOperator::NoUnsignedWrap>
    618 m_NUWMul(const LHS &L, const RHS &R) {
    619   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
    620                                    OverflowingBinaryOperator::NoUnsignedWrap>(
    621       L, R);
    622 }
    623 template <typename LHS, typename RHS>
    624 inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
    625                                  OverflowingBinaryOperator::NoUnsignedWrap>
    626 m_NUWShl(const LHS &L, const RHS &R) {
    627   return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
    628                                    OverflowingBinaryOperator::NoUnsignedWrap>(
    629       L, R);
    630 }
    631 
    632 //===----------------------------------------------------------------------===//
    633 // Class that matches two different binary ops.
    634 //
    635 template <typename LHS_t, typename RHS_t, unsigned Opc1, unsigned Opc2>
    636 struct BinOp2_match {
    637   LHS_t L;
    638   RHS_t R;
    639 
    640   BinOp2_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
    641 
    642   template <typename OpTy> bool match(OpTy *V) {
    643     if (V->getValueID() == Value::InstructionVal + Opc1 ||
    644         V->getValueID() == Value::InstructionVal + Opc2) {
    645       auto *I = cast<BinaryOperator>(V);
    646       return L.match(I->getOperand(0)) && R.match(I->getOperand(1));
    647     }
    648     if (auto *CE = dyn_cast<ConstantExpr>(V))
    649       return (CE->getOpcode() == Opc1 || CE->getOpcode() == Opc2) &&
    650              L.match(CE->getOperand(0)) && R.match(CE->getOperand(1));
    651     return false;
    652   }
    653 };
    654 
    655 /// \brief Matches LShr or AShr.
    656 template <typename LHS, typename RHS>
    657 inline BinOp2_match<LHS, RHS, Instruction::LShr, Instruction::AShr>
    658 m_Shr(const LHS &L, const RHS &R) {
    659   return BinOp2_match<LHS, RHS, Instruction::LShr, Instruction::AShr>(L, R);
    660 }
    661 
    662 /// \brief Matches LShr or Shl.
    663 template <typename LHS, typename RHS>
    664 inline BinOp2_match<LHS, RHS, Instruction::LShr, Instruction::Shl>
    665 m_LogicalShift(const LHS &L, const RHS &R) {
    666   return BinOp2_match<LHS, RHS, Instruction::LShr, Instruction::Shl>(L, R);
    667 }
    668 
    669 /// \brief Matches UDiv and SDiv.
    670 template <typename LHS, typename RHS>
    671 inline BinOp2_match<LHS, RHS, Instruction::SDiv, Instruction::UDiv>
    672 m_IDiv(const LHS &L, const RHS &R) {
    673   return BinOp2_match<LHS, RHS, Instruction::SDiv, Instruction::UDiv>(L, R);
    674 }
    675 
    676 //===----------------------------------------------------------------------===//
    677 // Class that matches exact binary ops.
    678 //
    679 template <typename SubPattern_t> struct Exact_match {
    680   SubPattern_t SubPattern;
    681 
    682   Exact_match(const SubPattern_t &SP) : SubPattern(SP) {}
    683 
    684   template <typename OpTy> bool match(OpTy *V) {
    685     if (PossiblyExactOperator *PEO = dyn_cast<PossiblyExactOperator>(V))
    686       return PEO->isExact() && SubPattern.match(V);
    687     return false;
    688   }
    689 };
    690 
    691 template <typename T> inline Exact_match<T> m_Exact(const T &SubPattern) {
    692   return SubPattern;
    693 }
    694 
    695 //===----------------------------------------------------------------------===//
    696 // Matchers for CmpInst classes
    697 //
    698 
    699 template <typename LHS_t, typename RHS_t, typename Class, typename PredicateTy>
    700 struct CmpClass_match {
    701   PredicateTy &Predicate;
    702   LHS_t L;
    703   RHS_t R;
    704 
    705   CmpClass_match(PredicateTy &Pred, const LHS_t &LHS, const RHS_t &RHS)
    706       : Predicate(Pred), L(LHS), R(RHS) {}
    707 
    708   template <typename OpTy> bool match(OpTy *V) {
    709     if (Class *I = dyn_cast<Class>(V))
    710       if (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) {
    711         Predicate = I->getPredicate();
    712         return true;
    713       }
    714     return false;
    715   }
    716 };
    717 
    718 template <typename LHS, typename RHS>
    719 inline CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>
    720 m_Cmp(CmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
    721   return CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>(Pred, L, R);
    722 }
    723 
    724 template <typename LHS, typename RHS>
    725 inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>
    726 m_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
    727   return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>(Pred, L, R);
    728 }
    729 
    730 template <typename LHS, typename RHS>
    731 inline CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>
    732 m_FCmp(FCmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
    733   return CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>(Pred, L, R);
    734 }
    735 
    736 //===----------------------------------------------------------------------===//
    737 // Matchers for SelectInst classes
    738 //
    739 
    740 template <typename Cond_t, typename LHS_t, typename RHS_t>
    741 struct SelectClass_match {
    742   Cond_t C;
    743   LHS_t L;
    744   RHS_t R;
    745 
    746   SelectClass_match(const Cond_t &Cond, const LHS_t &LHS, const RHS_t &RHS)
    747       : C(Cond), L(LHS), R(RHS) {}
    748 
    749   template <typename OpTy> bool match(OpTy *V) {
    750     if (auto *I = dyn_cast<SelectInst>(V))
    751       return C.match(I->getOperand(0)) && L.match(I->getOperand(1)) &&
    752              R.match(I->getOperand(2));
    753     return false;
    754   }
    755 };
    756 
    757 template <typename Cond, typename LHS, typename RHS>
    758 inline SelectClass_match<Cond, LHS, RHS> m_Select(const Cond &C, const LHS &L,
    759                                                   const RHS &R) {
    760   return SelectClass_match<Cond, LHS, RHS>(C, L, R);
    761 }
    762 
    763 /// \brief This matches a select of two constants, e.g.:
    764 /// m_SelectCst<-1, 0>(m_Value(V))
    765 template <int64_t L, int64_t R, typename Cond>
    766 inline SelectClass_match<Cond, constantint_match<L>, constantint_match<R>>
    767 m_SelectCst(const Cond &C) {
    768   return m_Select(C, m_ConstantInt<L>(), m_ConstantInt<R>());
    769 }
    770 
    771 //===----------------------------------------------------------------------===//
    772 // Matchers for CastInst classes
    773 //
    774 
    775 template <typename Op_t, unsigned Opcode> struct CastClass_match {
    776   Op_t Op;
    777 
    778   CastClass_match(const Op_t &OpMatch) : Op(OpMatch) {}
    779 
    780   template <typename OpTy> bool match(OpTy *V) {
    781     if (auto *O = dyn_cast<Operator>(V))
    782       return O->getOpcode() == Opcode && Op.match(O->getOperand(0));
    783     return false;
    784   }
    785 };
    786 
    787 /// \brief Matches BitCast.
    788 template <typename OpTy>
    789 inline CastClass_match<OpTy, Instruction::BitCast> m_BitCast(const OpTy &Op) {
    790   return CastClass_match<OpTy, Instruction::BitCast>(Op);
    791 }
    792 
    793 /// \brief Matches PtrToInt.
    794 template <typename OpTy>
    795 inline CastClass_match<OpTy, Instruction::PtrToInt> m_PtrToInt(const OpTy &Op) {
    796   return CastClass_match<OpTy, Instruction::PtrToInt>(Op);
    797 }
    798 
    799 /// \brief Matches Trunc.
    800 template <typename OpTy>
    801 inline CastClass_match<OpTy, Instruction::Trunc> m_Trunc(const OpTy &Op) {
    802   return CastClass_match<OpTy, Instruction::Trunc>(Op);
    803 }
    804 
    805 /// \brief Matches SExt.
    806 template <typename OpTy>
    807 inline CastClass_match<OpTy, Instruction::SExt> m_SExt(const OpTy &Op) {
    808   return CastClass_match<OpTy, Instruction::SExt>(Op);
    809 }
    810 
    811 /// \brief Matches ZExt.
    812 template <typename OpTy>
    813 inline CastClass_match<OpTy, Instruction::ZExt> m_ZExt(const OpTy &Op) {
    814   return CastClass_match<OpTy, Instruction::ZExt>(Op);
    815 }
    816 
    817 /// \brief Matches UIToFP.
    818 template <typename OpTy>
    819 inline CastClass_match<OpTy, Instruction::UIToFP> m_UIToFP(const OpTy &Op) {
    820   return CastClass_match<OpTy, Instruction::UIToFP>(Op);
    821 }
    822 
    823 /// \brief Matches SIToFP.
    824 template <typename OpTy>
    825 inline CastClass_match<OpTy, Instruction::SIToFP> m_SIToFP(const OpTy &Op) {
    826   return CastClass_match<OpTy, Instruction::SIToFP>(Op);
    827 }
    828 
    829 //===----------------------------------------------------------------------===//
    830 // Matchers for unary operators
    831 //
    832 
    833 template <typename LHS_t> struct not_match {
    834   LHS_t L;
    835 
    836   not_match(const LHS_t &LHS) : L(LHS) {}
    837 
    838   template <typename OpTy> bool match(OpTy *V) {
    839     if (auto *O = dyn_cast<Operator>(V))
    840       if (O->getOpcode() == Instruction::Xor)
    841         return matchIfNot(O->getOperand(0), O->getOperand(1));
    842     return false;
    843   }
    844 
    845 private:
    846   bool matchIfNot(Value *LHS, Value *RHS) {
    847     return (isa<ConstantInt>(RHS) || isa<ConstantDataVector>(RHS) ||
    848             // FIXME: Remove CV.
    849             isa<ConstantVector>(RHS)) &&
    850            cast<Constant>(RHS)->isAllOnesValue() && L.match(LHS);
    851   }
    852 };
    853 
    854 template <typename LHS> inline not_match<LHS> m_Not(const LHS &L) { return L; }
    855 
    856 template <typename LHS_t> struct neg_match {
    857   LHS_t L;
    858 
    859   neg_match(const LHS_t &LHS) : L(LHS) {}
    860 
    861   template <typename OpTy> bool match(OpTy *V) {
    862     if (auto *O = dyn_cast<Operator>(V))
    863       if (O->getOpcode() == Instruction::Sub)
    864         return matchIfNeg(O->getOperand(0), O->getOperand(1));
    865     return false;
    866   }
    867 
    868 private:
    869   bool matchIfNeg(Value *LHS, Value *RHS) {
    870     return ((isa<ConstantInt>(LHS) && cast<ConstantInt>(LHS)->isZero()) ||
    871             isa<ConstantAggregateZero>(LHS)) &&
    872            L.match(RHS);
    873   }
    874 };
    875 
    876 /// \brief Match an integer negate.
    877 template <typename LHS> inline neg_match<LHS> m_Neg(const LHS &L) { return L; }
    878 
    879 template <typename LHS_t> struct fneg_match {
    880   LHS_t L;
    881 
    882   fneg_match(const LHS_t &LHS) : L(LHS) {}
    883 
    884   template <typename OpTy> bool match(OpTy *V) {
    885     if (auto *O = dyn_cast<Operator>(V))
    886       if (O->getOpcode() == Instruction::FSub)
    887         return matchIfFNeg(O->getOperand(0), O->getOperand(1));
    888     return false;
    889   }
    890 
    891 private:
    892   bool matchIfFNeg(Value *LHS, Value *RHS) {
    893     if (const auto *C = dyn_cast<ConstantFP>(LHS))
    894       return C->isNegativeZeroValue() && L.match(RHS);
    895     return false;
    896   }
    897 };
    898 
    899 /// \brief Match a floating point negate.
    900 template <typename LHS> inline fneg_match<LHS> m_FNeg(const LHS &L) {
    901   return L;
    902 }
    903 
    904 //===----------------------------------------------------------------------===//
    905 // Matchers for control flow.
    906 //
    907 
    908 struct br_match {
    909   BasicBlock *&Succ;
    910   br_match(BasicBlock *&Succ) : Succ(Succ) {}
    911 
    912   template <typename OpTy> bool match(OpTy *V) {
    913     if (auto *BI = dyn_cast<BranchInst>(V))
    914       if (BI->isUnconditional()) {
    915         Succ = BI->getSuccessor(0);
    916         return true;
    917       }
    918     return false;
    919   }
    920 };
    921 
    922 inline br_match m_UnconditionalBr(BasicBlock *&Succ) { return br_match(Succ); }
    923 
    924 template <typename Cond_t> struct brc_match {
    925   Cond_t Cond;
    926   BasicBlock *&T, *&F;
    927   brc_match(const Cond_t &C, BasicBlock *&t, BasicBlock *&f)
    928       : Cond(C), T(t), F(f) {}
    929 
    930   template <typename OpTy> bool match(OpTy *V) {
    931     if (auto *BI = dyn_cast<BranchInst>(V))
    932       if (BI->isConditional() && Cond.match(BI->getCondition())) {
    933         T = BI->getSuccessor(0);
    934         F = BI->getSuccessor(1);
    935         return true;
    936       }
    937     return false;
    938   }
    939 };
    940 
    941 template <typename Cond_t>
    942 inline brc_match<Cond_t> m_Br(const Cond_t &C, BasicBlock *&T, BasicBlock *&F) {
    943   return brc_match<Cond_t>(C, T, F);
    944 }
    945 
    946 //===----------------------------------------------------------------------===//
    947 // Matchers for max/min idioms, eg: "select (sgt x, y), x, y" -> smax(x,y).
    948 //
    949 
    950 template <typename CmpInst_t, typename LHS_t, typename RHS_t, typename Pred_t>
    951 struct MaxMin_match {
    952   LHS_t L;
    953   RHS_t R;
    954 
    955   MaxMin_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
    956 
    957   template <typename OpTy> bool match(OpTy *V) {
    958     // Look for "(x pred y) ? x : y" or "(x pred y) ? y : x".
    959     auto *SI = dyn_cast<SelectInst>(V);
    960     if (!SI)
    961       return false;
    962     auto *Cmp = dyn_cast<CmpInst_t>(SI->getCondition());
    963     if (!Cmp)
    964       return false;
    965     // At this point we have a select conditioned on a comparison.  Check that
    966     // it is the values returned by the select that are being compared.
    967     Value *TrueVal = SI->getTrueValue();
    968     Value *FalseVal = SI->getFalseValue();
    969     Value *LHS = Cmp->getOperand(0);
    970     Value *RHS = Cmp->getOperand(1);
    971     if ((TrueVal != LHS || FalseVal != RHS) &&
    972         (TrueVal != RHS || FalseVal != LHS))
    973       return false;
    974     typename CmpInst_t::Predicate Pred =
    975         LHS == TrueVal ? Cmp->getPredicate() : Cmp->getSwappedPredicate();
    976     // Does "(x pred y) ? x : y" represent the desired max/min operation?
    977     if (!Pred_t::match(Pred))
    978       return false;
    979     // It does!  Bind the operands.
    980     return L.match(LHS) && R.match(RHS);
    981   }
    982 };
    983 
    984 /// \brief Helper class for identifying signed max predicates.
    985 struct smax_pred_ty {
    986   static bool match(ICmpInst::Predicate Pred) {
    987     return Pred == CmpInst::ICMP_SGT || Pred == CmpInst::ICMP_SGE;
    988   }
    989 };
    990 
    991 /// \brief Helper class for identifying signed min predicates.
    992 struct smin_pred_ty {
    993   static bool match(ICmpInst::Predicate Pred) {
    994     return Pred == CmpInst::ICMP_SLT || Pred == CmpInst::ICMP_SLE;
    995   }
    996 };
    997 
    998 /// \brief Helper class for identifying unsigned max predicates.
    999 struct umax_pred_ty {
   1000   static bool match(ICmpInst::Predicate Pred) {
   1001     return Pred == CmpInst::ICMP_UGT || Pred == CmpInst::ICMP_UGE;
   1002   }
   1003 };
   1004 
   1005 /// \brief Helper class for identifying unsigned min predicates.
   1006 struct umin_pred_ty {
   1007   static bool match(ICmpInst::Predicate Pred) {
   1008     return Pred == CmpInst::ICMP_ULT || Pred == CmpInst::ICMP_ULE;
   1009   }
   1010 };
   1011 
   1012 /// \brief Helper class for identifying ordered max predicates.
   1013 struct ofmax_pred_ty {
   1014   static bool match(FCmpInst::Predicate Pred) {
   1015     return Pred == CmpInst::FCMP_OGT || Pred == CmpInst::FCMP_OGE;
   1016   }
   1017 };
   1018 
   1019 /// \brief Helper class for identifying ordered min predicates.
   1020 struct ofmin_pred_ty {
   1021   static bool match(FCmpInst::Predicate Pred) {
   1022     return Pred == CmpInst::FCMP_OLT || Pred == CmpInst::FCMP_OLE;
   1023   }
   1024 };
   1025 
   1026 /// \brief Helper class for identifying unordered max predicates.
   1027 struct ufmax_pred_ty {
   1028   static bool match(FCmpInst::Predicate Pred) {
   1029     return Pred == CmpInst::FCMP_UGT || Pred == CmpInst::FCMP_UGE;
   1030   }
   1031 };
   1032 
   1033 /// \brief Helper class for identifying unordered min predicates.
   1034 struct ufmin_pred_ty {
   1035   static bool match(FCmpInst::Predicate Pred) {
   1036     return Pred == CmpInst::FCMP_ULT || Pred == CmpInst::FCMP_ULE;
   1037   }
   1038 };
   1039 
   1040 template <typename LHS, typename RHS>
   1041 inline MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty> m_SMax(const LHS &L,
   1042                                                              const RHS &R) {
   1043   return MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty>(L, R);
   1044 }
   1045 
   1046 template <typename LHS, typename RHS>
   1047 inline MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty> m_SMin(const LHS &L,
   1048                                                              const RHS &R) {
   1049   return MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty>(L, R);
   1050 }
   1051 
   1052 template <typename LHS, typename RHS>
   1053 inline MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty> m_UMax(const LHS &L,
   1054                                                              const RHS &R) {
   1055   return MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty>(L, R);
   1056 }
   1057 
   1058 template <typename LHS, typename RHS>
   1059 inline MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty> m_UMin(const LHS &L,
   1060                                                              const RHS &R) {
   1061   return MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty>(L, R);
   1062 }
   1063 
   1064 /// \brief Match an 'ordered' floating point maximum function.
   1065 /// Floating point has one special value 'NaN'. Therefore, there is no total
   1066 /// order. However, if we can ignore the 'NaN' value (for example, because of a
   1067 /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
   1068 /// semantics. In the presence of 'NaN' we have to preserve the original
   1069 /// select(fcmp(ogt/ge, L, R), L, R) semantics matched by this predicate.
   1070 ///
   1071 ///                         max(L, R)  iff L and R are not NaN
   1072 ///  m_OrdFMax(L, R) =      R          iff L or R are NaN
   1073 template <typename LHS, typename RHS>
   1074 inline MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty> m_OrdFMax(const LHS &L,
   1075                                                                  const RHS &R) {
   1076   return MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty>(L, R);
   1077 }
   1078 
   1079 /// \brief Match an 'ordered' floating point minimum function.
   1080 /// Floating point has one special value 'NaN'. Therefore, there is no total
   1081 /// order. However, if we can ignore the 'NaN' value (for example, because of a
   1082 /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
   1083 /// semantics. In the presence of 'NaN' we have to preserve the original
   1084 /// select(fcmp(olt/le, L, R), L, R) semantics matched by this predicate.
   1085 ///
   1086 ///                         max(L, R)  iff L and R are not NaN
   1087 ///  m_OrdFMin(L, R) =      R          iff L or R are NaN
   1088 template <typename LHS, typename RHS>
   1089 inline MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty> m_OrdFMin(const LHS &L,
   1090                                                                  const RHS &R) {
   1091   return MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty>(L, R);
   1092 }
   1093 
   1094 /// \brief Match an 'unordered' floating point maximum function.
   1095 /// Floating point has one special value 'NaN'. Therefore, there is no total
   1096 /// order. However, if we can ignore the 'NaN' value (for example, because of a
   1097 /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
   1098 /// semantics. In the presence of 'NaN' we have to preserve the original
   1099 /// select(fcmp(ugt/ge, L, R), L, R) semantics matched by this predicate.
   1100 ///
   1101 ///                         max(L, R)  iff L and R are not NaN
   1102 ///  m_UnordFMin(L, R) =    L          iff L or R are NaN
   1103 template <typename LHS, typename RHS>
   1104 inline MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>
   1105 m_UnordFMax(const LHS &L, const RHS &R) {
   1106   return MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>(L, R);
   1107 }
   1108 
   1109 //===----------------------------------------------------------------------===//
   1110 // Matchers for overflow check patterns: e.g. (a + b) u< a
   1111 //
   1112 
   1113 template <typename LHS_t, typename RHS_t, typename Sum_t>
   1114 struct UAddWithOverflow_match {
   1115   LHS_t L;
   1116   RHS_t R;
   1117   Sum_t S;
   1118 
   1119   UAddWithOverflow_match(const LHS_t &L, const RHS_t &R, const Sum_t &S)
   1120       : L(L), R(R), S(S) {}
   1121 
   1122   template <typename OpTy> bool match(OpTy *V) {
   1123     Value *ICmpLHS, *ICmpRHS;
   1124     ICmpInst::Predicate Pred;
   1125     if (!m_ICmp(Pred, m_Value(ICmpLHS), m_Value(ICmpRHS)).match(V))
   1126       return false;
   1127 
   1128     Value *AddLHS, *AddRHS;
   1129     auto AddExpr = m_Add(m_Value(AddLHS), m_Value(AddRHS));
   1130 
   1131     // (a + b) u< a, (a + b) u< b
   1132     if (Pred == ICmpInst::ICMP_ULT)
   1133       if (AddExpr.match(ICmpLHS) && (ICmpRHS == AddLHS || ICmpRHS == AddRHS))
   1134         return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
   1135 
   1136     // a >u (a + b), b >u (a + b)
   1137     if (Pred == ICmpInst::ICMP_UGT)
   1138       if (AddExpr.match(ICmpRHS) && (ICmpLHS == AddLHS || ICmpLHS == AddRHS))
   1139         return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
   1140 
   1141     return false;
   1142   }
   1143 };
   1144 
   1145 /// \brief Match an icmp instruction checking for unsigned overflow on addition.
   1146 ///
   1147 /// S is matched to the addition whose result is being checked for overflow, and
   1148 /// L and R are matched to the LHS and RHS of S.
   1149 template <typename LHS_t, typename RHS_t, typename Sum_t>
   1150 UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>
   1151 m_UAddWithOverflow(const LHS_t &L, const RHS_t &R, const Sum_t &S) {
   1152   return UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>(L, R, S);
   1153 }
   1154 
   1155 /// \brief Match an 'unordered' floating point minimum function.
   1156 /// Floating point has one special value 'NaN'. Therefore, there is no total
   1157 /// order. However, if we can ignore the 'NaN' value (for example, because of a
   1158 /// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
   1159 /// semantics. In the presence of 'NaN' we have to preserve the original
   1160 /// select(fcmp(ult/le, L, R), L, R) semantics matched by this predicate.
   1161 ///
   1162 ///                          max(L, R)  iff L and R are not NaN
   1163 ///  m_UnordFMin(L, R) =     L          iff L or R are NaN
   1164 template <typename LHS, typename RHS>
   1165 inline MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>
   1166 m_UnordFMin(const LHS &L, const RHS &R) {
   1167   return MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>(L, R);
   1168 }
   1169 
   1170 template <typename Opnd_t> struct Argument_match {
   1171   unsigned OpI;
   1172   Opnd_t Val;
   1173   Argument_match(unsigned OpIdx, const Opnd_t &V) : OpI(OpIdx), Val(V) {}
   1174 
   1175   template <typename OpTy> bool match(OpTy *V) {
   1176     CallSite CS(V);
   1177     return CS.isCall() && Val.match(CS.getArgument(OpI));
   1178   }
   1179 };
   1180 
   1181 /// \brief Match an argument.
   1182 template <unsigned OpI, typename Opnd_t>
   1183 inline Argument_match<Opnd_t> m_Argument(const Opnd_t &Op) {
   1184   return Argument_match<Opnd_t>(OpI, Op);
   1185 }
   1186 
   1187 /// \brief Intrinsic matchers.
   1188 struct IntrinsicID_match {
   1189   unsigned ID;
   1190   IntrinsicID_match(Intrinsic::ID IntrID) : ID(IntrID) {}
   1191 
   1192   template <typename OpTy> bool match(OpTy *V) {
   1193     if (const auto *CI = dyn_cast<CallInst>(V))
   1194       if (const auto *F = CI->getCalledFunction())
   1195         return F->getIntrinsicID() == ID;
   1196     return false;
   1197   }
   1198 };
   1199 
   1200 /// Intrinsic matches are combinations of ID matchers, and argument
   1201 /// matchers. Higher arity matcher are defined recursively in terms of and-ing
   1202 /// them with lower arity matchers. Here's some convenient typedefs for up to
   1203 /// several arguments, and more can be added as needed
   1204 template <typename T0 = void, typename T1 = void, typename T2 = void,
   1205           typename T3 = void, typename T4 = void, typename T5 = void,
   1206           typename T6 = void, typename T7 = void, typename T8 = void,
   1207           typename T9 = void, typename T10 = void>
   1208 struct m_Intrinsic_Ty;
   1209 template <typename T0> struct m_Intrinsic_Ty<T0> {
   1210   typedef match_combine_and<IntrinsicID_match, Argument_match<T0>> Ty;
   1211 };
   1212 template <typename T0, typename T1> struct m_Intrinsic_Ty<T0, T1> {
   1213   typedef match_combine_and<typename m_Intrinsic_Ty<T0>::Ty, Argument_match<T1>>
   1214       Ty;
   1215 };
   1216 template <typename T0, typename T1, typename T2>
   1217 struct m_Intrinsic_Ty<T0, T1, T2> {
   1218   typedef match_combine_and<typename m_Intrinsic_Ty<T0, T1>::Ty,
   1219                             Argument_match<T2>> Ty;
   1220 };
   1221 template <typename T0, typename T1, typename T2, typename T3>
   1222 struct m_Intrinsic_Ty<T0, T1, T2, T3> {
   1223   typedef match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2>::Ty,
   1224                             Argument_match<T3>> Ty;
   1225 };
   1226 
   1227 /// \brief Match intrinsic calls like this:
   1228 /// m_Intrinsic<Intrinsic::fabs>(m_Value(X))
   1229 template <Intrinsic::ID IntrID> inline IntrinsicID_match m_Intrinsic() {
   1230   return IntrinsicID_match(IntrID);
   1231 }
   1232 
   1233 template <Intrinsic::ID IntrID, typename T0>
   1234 inline typename m_Intrinsic_Ty<T0>::Ty m_Intrinsic(const T0 &Op0) {
   1235   return m_CombineAnd(m_Intrinsic<IntrID>(), m_Argument<0>(Op0));
   1236 }
   1237 
   1238 template <Intrinsic::ID IntrID, typename T0, typename T1>
   1239 inline typename m_Intrinsic_Ty<T0, T1>::Ty m_Intrinsic(const T0 &Op0,
   1240                                                        const T1 &Op1) {
   1241   return m_CombineAnd(m_Intrinsic<IntrID>(Op0), m_Argument<1>(Op1));
   1242 }
   1243 
   1244 template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2>
   1245 inline typename m_Intrinsic_Ty<T0, T1, T2>::Ty
   1246 m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2) {
   1247   return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1), m_Argument<2>(Op2));
   1248 }
   1249 
   1250 template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
   1251           typename T3>
   1252 inline typename m_Intrinsic_Ty<T0, T1, T2, T3>::Ty
   1253 m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3) {
   1254   return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2), m_Argument<3>(Op3));
   1255 }
   1256 
   1257 // Helper intrinsic matching specializations.
   1258 template <typename Opnd0>
   1259 inline typename m_Intrinsic_Ty<Opnd0>::Ty m_BSwap(const Opnd0 &Op0) {
   1260   return m_Intrinsic<Intrinsic::bswap>(Op0);
   1261 }
   1262 
   1263 template <typename Opnd0, typename Opnd1>
   1264 inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMin(const Opnd0 &Op0,
   1265                                                         const Opnd1 &Op1) {
   1266   return m_Intrinsic<Intrinsic::minnum>(Op0, Op1);
   1267 }
   1268 
   1269 template <typename Opnd0, typename Opnd1>
   1270 inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMax(const Opnd0 &Op0,
   1271                                                         const Opnd1 &Op1) {
   1272   return m_Intrinsic<Intrinsic::maxnum>(Op0, Op1);
   1273 }
   1274 
   1275 template <typename Opnd_t> struct Signum_match {
   1276   Opnd_t Val;
   1277   Signum_match(const Opnd_t &V) : Val(V) {}
   1278 
   1279   template <typename OpTy> bool match(OpTy *V) {
   1280     unsigned TypeSize = V->getType()->getScalarSizeInBits();
   1281     if (TypeSize == 0)
   1282       return false;
   1283 
   1284     unsigned ShiftWidth = TypeSize - 1;
   1285     Value *OpL = nullptr, *OpR = nullptr;
   1286 
   1287     // This is the representation of signum we match:
   1288     //
   1289     //  signum(x) == (x >> 63) | (-x >>u 63)
   1290     //
   1291     // An i1 value is its own signum, so it's correct to match
   1292     //
   1293     //  signum(x) == (x >> 0)  | (-x >>u 0)
   1294     //
   1295     // for i1 values.
   1296 
   1297     auto LHS = m_AShr(m_Value(OpL), m_SpecificInt(ShiftWidth));
   1298     auto RHS = m_LShr(m_Neg(m_Value(OpR)), m_SpecificInt(ShiftWidth));
   1299     auto Signum = m_Or(LHS, RHS);
   1300 
   1301     return Signum.match(V) && OpL == OpR && Val.match(OpL);
   1302   }
   1303 };
   1304 
   1305 /// \brief Matches a signum pattern.
   1306 ///
   1307 /// signum(x) =
   1308 ///      x >  0  ->  1
   1309 ///      x == 0  ->  0
   1310 ///      x <  0  -> -1
   1311 template <typename Val_t> inline Signum_match<Val_t> m_Signum(const Val_t &V) {
   1312   return Signum_match<Val_t>(V);
   1313 }
   1314 
   1315 //===----------------------------------------------------------------------===//
   1316 // Matchers for two-operands operators with the operators in either order
   1317 //
   1318 
   1319 /// \brief Matches an ICmp with a predicate over LHS and RHS in either order.
   1320 /// Does not swap the predicate.
   1321 template<typename LHS, typename RHS>
   1322 inline match_combine_or<CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>,
   1323                         CmpClass_match<RHS, LHS, ICmpInst, ICmpInst::Predicate>>
   1324 m_c_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
   1325   return m_CombineOr(m_ICmp(Pred, L, R), m_ICmp(Pred, R, L));
   1326 }
   1327 
   1328 /// \brief Matches an And with LHS and RHS in either order.
   1329 template<typename LHS, typename RHS>
   1330 inline match_combine_or<BinaryOp_match<LHS, RHS, Instruction::And>,
   1331                         BinaryOp_match<RHS, LHS, Instruction::And>>
   1332 m_c_And(const LHS &L, const RHS &R) {
   1333   return m_CombineOr(m_And(L, R), m_And(R, L));
   1334 }
   1335 
   1336 /// \brief Matches an Or with LHS and RHS in either order.
   1337 template<typename LHS, typename RHS>
   1338 inline match_combine_or<BinaryOp_match<LHS, RHS, Instruction::Or>,
   1339                         BinaryOp_match<RHS, LHS, Instruction::Or>>
   1340 m_c_Or(const LHS &L, const RHS &R) {
   1341   return m_CombineOr(m_Or(L, R), m_Or(R, L));
   1342 }
   1343 
   1344 /// \brief Matches an Xor with LHS and RHS in either order.
   1345 template<typename LHS, typename RHS>
   1346 inline match_combine_or<BinaryOp_match<LHS, RHS, Instruction::Xor>,
   1347                         BinaryOp_match<RHS, LHS, Instruction::Xor>>
   1348 m_c_Xor(const LHS &L, const RHS &R) {
   1349   return m_CombineOr(m_Xor(L, R), m_Xor(R, L));
   1350 }
   1351 
   1352 } // end namespace PatternMatch
   1353 } // end namespace llvm
   1354 
   1355 #endif
   1356