| //===- llvm/Analysis/ScalarEvolutionExpressions.h - SCEV Exprs --*- 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 defines the classes used to represent and build scalar expressions. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H |
| #define LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H |
| |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/FoldingSet.h" |
| #include "llvm/ADT/SmallPtrSet.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/iterator_range.h" |
| #include "llvm/Analysis/ScalarEvolution.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/Value.h" |
| #include "llvm/IR/ValueHandle.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include <cassert> |
| #include <cstddef> |
| |
| namespace llvm { |
| |
| class APInt; |
| class Constant; |
| class ConstantRange; |
| class Loop; |
| class Type; |
| |
| enum SCEVTypes { |
| // These should be ordered in terms of increasing complexity to make the |
| // folders simpler. |
| scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr, |
| scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr, |
| scUnknown, scCouldNotCompute |
| }; |
| |
| /// This class represents a constant integer value. |
| class SCEVConstant : public SCEV { |
| friend class ScalarEvolution; |
| |
| ConstantInt *V; |
| |
| SCEVConstant(const FoldingSetNodeIDRef ID, ConstantInt *v) : |
| SCEV(ID, scConstant, 1), V(v) {} |
| |
| public: |
| ConstantInt *getValue() const { return V; } |
| const APInt &getAPInt() const { return getValue()->getValue(); } |
| |
| Type *getType() const { return V->getType(); } |
| |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scConstant; |
| } |
| }; |
| |
| static unsigned short computeExpressionSize(ArrayRef<const SCEV *> Args) { |
| APInt Size(16, 1); |
| for (auto *Arg : Args) |
| Size = Size.uadd_sat(APInt(16, Arg->getExpressionSize())); |
| return (unsigned short)Size.getZExtValue(); |
| } |
| |
| /// This is the base class for unary cast operator classes. |
| class SCEVCastExpr : public SCEV { |
| protected: |
| const SCEV *Op; |
| Type *Ty; |
| |
| SCEVCastExpr(const FoldingSetNodeIDRef ID, |
| unsigned SCEVTy, const SCEV *op, Type *ty); |
| |
| public: |
| const SCEV *getOperand() const { return Op; } |
| Type *getType() const { return Ty; } |
| |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scTruncate || |
| S->getSCEVType() == scZeroExtend || |
| S->getSCEVType() == scSignExtend; |
| } |
| }; |
| |
| /// This class represents a truncation of an integer value to a |
| /// smaller integer value. |
| class SCEVTruncateExpr : public SCEVCastExpr { |
| friend class ScalarEvolution; |
| |
| SCEVTruncateExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *op, Type *ty); |
| |
| public: |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scTruncate; |
| } |
| }; |
| |
| /// This class represents a zero extension of a small integer value |
| /// to a larger integer value. |
| class SCEVZeroExtendExpr : public SCEVCastExpr { |
| friend class ScalarEvolution; |
| |
| SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *op, Type *ty); |
| |
| public: |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scZeroExtend; |
| } |
| }; |
| |
| /// This class represents a sign extension of a small integer value |
| /// to a larger integer value. |
| class SCEVSignExtendExpr : public SCEVCastExpr { |
| friend class ScalarEvolution; |
| |
| SCEVSignExtendExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *op, Type *ty); |
| |
| public: |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scSignExtend; |
| } |
| }; |
| |
| /// This node is a base class providing common functionality for |
| /// n'ary operators. |
| class SCEVNAryExpr : public SCEV { |
| protected: |
| // Since SCEVs are immutable, ScalarEvolution allocates operand |
| // arrays with its SCEVAllocator, so this class just needs a simple |
| // pointer rather than a more elaborate vector-like data structure. |
| // This also avoids the need for a non-trivial destructor. |
| const SCEV *const *Operands; |
| size_t NumOperands; |
| |
| SCEVNAryExpr(const FoldingSetNodeIDRef ID, enum SCEVTypes T, |
| const SCEV *const *O, size_t N) |
| : SCEV(ID, T, computeExpressionSize(makeArrayRef(O, N))), Operands(O), |
| NumOperands(N) {} |
| |
| public: |
| size_t getNumOperands() const { return NumOperands; } |
| |
| const SCEV *getOperand(unsigned i) const { |
| assert(i < NumOperands && "Operand index out of range!"); |
| return Operands[i]; |
| } |
| |
| using op_iterator = const SCEV *const *; |
| using op_range = iterator_range<op_iterator>; |
| |
| op_iterator op_begin() const { return Operands; } |
| op_iterator op_end() const { return Operands + NumOperands; } |
| op_range operands() const { |
| return make_range(op_begin(), op_end()); |
| } |
| |
| Type *getType() const { return getOperand(0)->getType(); } |
| |
| NoWrapFlags getNoWrapFlags(NoWrapFlags Mask = NoWrapMask) const { |
| return (NoWrapFlags)(SubclassData & Mask); |
| } |
| |
| bool hasNoUnsignedWrap() const { |
| return getNoWrapFlags(FlagNUW) != FlagAnyWrap; |
| } |
| |
| bool hasNoSignedWrap() const { |
| return getNoWrapFlags(FlagNSW) != FlagAnyWrap; |
| } |
| |
| bool hasNoSelfWrap() const { |
| return getNoWrapFlags(FlagNW) != FlagAnyWrap; |
| } |
| |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scAddExpr || |
| S->getSCEVType() == scMulExpr || |
| S->getSCEVType() == scSMaxExpr || |
| S->getSCEVType() == scUMaxExpr || |
| S->getSCEVType() == scAddRecExpr; |
| } |
| }; |
| |
| /// This node is the base class for n'ary commutative operators. |
| class SCEVCommutativeExpr : public SCEVNAryExpr { |
| protected: |
| SCEVCommutativeExpr(const FoldingSetNodeIDRef ID, |
| enum SCEVTypes T, const SCEV *const *O, size_t N) |
| : SCEVNAryExpr(ID, T, O, N) {} |
| |
| public: |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scAddExpr || |
| S->getSCEVType() == scMulExpr || |
| S->getSCEVType() == scSMaxExpr || |
| S->getSCEVType() == scUMaxExpr; |
| } |
| |
| /// Set flags for a non-recurrence without clearing previously set flags. |
| void setNoWrapFlags(NoWrapFlags Flags) { |
| SubclassData |= Flags; |
| } |
| }; |
| |
| /// This node represents an addition of some number of SCEVs. |
| class SCEVAddExpr : public SCEVCommutativeExpr { |
| friend class ScalarEvolution; |
| |
| SCEVAddExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *const *O, size_t N) |
| : SCEVCommutativeExpr(ID, scAddExpr, O, N) {} |
| |
| public: |
| Type *getType() const { |
| // Use the type of the last operand, which is likely to be a pointer |
| // type, if there is one. This doesn't usually matter, but it can help |
| // reduce casts when the expressions are expanded. |
| return getOperand(getNumOperands() - 1)->getType(); |
| } |
| |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scAddExpr; |
| } |
| }; |
| |
| /// This node represents multiplication of some number of SCEVs. |
| class SCEVMulExpr : public SCEVCommutativeExpr { |
| friend class ScalarEvolution; |
| |
| SCEVMulExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *const *O, size_t N) |
| : SCEVCommutativeExpr(ID, scMulExpr, O, N) {} |
| |
| public: |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scMulExpr; |
| } |
| }; |
| |
| /// This class represents a binary unsigned division operation. |
| class SCEVUDivExpr : public SCEV { |
| friend class ScalarEvolution; |
| |
| const SCEV *LHS; |
| const SCEV *RHS; |
| |
| SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs) |
| : SCEV(ID, scUDivExpr, computeExpressionSize({lhs, rhs})), LHS(lhs), |
| RHS(rhs) {} |
| |
| public: |
| const SCEV *getLHS() const { return LHS; } |
| const SCEV *getRHS() const { return RHS; } |
| |
| Type *getType() const { |
| // In most cases the types of LHS and RHS will be the same, but in some |
| // crazy cases one or the other may be a pointer. ScalarEvolution doesn't |
| // depend on the type for correctness, but handling types carefully can |
| // avoid extra casts in the SCEVExpander. The LHS is more likely to be |
| // a pointer type than the RHS, so use the RHS' type here. |
| return getRHS()->getType(); |
| } |
| |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scUDivExpr; |
| } |
| }; |
| |
| /// This node represents a polynomial recurrence on the trip count |
| /// of the specified loop. This is the primary focus of the |
| /// ScalarEvolution framework; all the other SCEV subclasses are |
| /// mostly just supporting infrastructure to allow SCEVAddRecExpr |
| /// expressions to be created and analyzed. |
| /// |
| /// All operands of an AddRec are required to be loop invariant. |
| /// |
| class SCEVAddRecExpr : public SCEVNAryExpr { |
| friend class ScalarEvolution; |
| |
| const Loop *L; |
| |
| SCEVAddRecExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *const *O, size_t N, const Loop *l) |
| : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {} |
| |
| public: |
| const SCEV *getStart() const { return Operands[0]; } |
| const Loop *getLoop() const { return L; } |
| |
| /// Constructs and returns the recurrence indicating how much this |
| /// expression steps by. If this is a polynomial of degree N, it |
| /// returns a chrec of degree N-1. We cannot determine whether |
| /// the step recurrence has self-wraparound. |
| const SCEV *getStepRecurrence(ScalarEvolution &SE) const { |
| if (isAffine()) return getOperand(1); |
| return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1, |
| op_end()), |
| getLoop(), FlagAnyWrap); |
| } |
| |
| /// Return true if this represents an expression A + B*x where A |
| /// and B are loop invariant values. |
| bool isAffine() const { |
| // We know that the start value is invariant. This expression is thus |
| // affine iff the step is also invariant. |
| return getNumOperands() == 2; |
| } |
| |
| /// Return true if this represents an expression A + B*x + C*x^2 |
| /// where A, B and C are loop invariant values. This corresponds |
| /// to an addrec of the form {L,+,M,+,N} |
| bool isQuadratic() const { |
| return getNumOperands() == 3; |
| } |
| |
| /// Set flags for a recurrence without clearing any previously set flags. |
| /// For AddRec, either NUW or NSW implies NW. Keep track of this fact here |
| /// to make it easier to propagate flags. |
| void setNoWrapFlags(NoWrapFlags Flags) { |
| if (Flags & (FlagNUW | FlagNSW)) |
| Flags = ScalarEvolution::setFlags(Flags, FlagNW); |
| SubclassData |= Flags; |
| } |
| |
| /// Return the value of this chain of recurrences at the specified |
| /// iteration number. |
| const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const; |
| |
| /// Return the number of iterations of this loop that produce |
| /// values in the specified constant range. Another way of |
| /// looking at this is that it returns the first iteration number |
| /// where the value is not in the condition, thus computing the |
| /// exit count. If the iteration count can't be computed, an |
| /// instance of SCEVCouldNotCompute is returned. |
| const SCEV *getNumIterationsInRange(const ConstantRange &Range, |
| ScalarEvolution &SE) const; |
| |
| /// Return an expression representing the value of this expression |
| /// one iteration of the loop ahead. |
| const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const; |
| |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scAddRecExpr; |
| } |
| }; |
| |
| /// This class represents a signed maximum selection. |
| class SCEVSMaxExpr : public SCEVCommutativeExpr { |
| friend class ScalarEvolution; |
| |
| SCEVSMaxExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *const *O, size_t N) |
| : SCEVCommutativeExpr(ID, scSMaxExpr, O, N) { |
| // Max never overflows. |
| setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW)); |
| } |
| |
| public: |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scSMaxExpr; |
| } |
| }; |
| |
| /// This class represents an unsigned maximum selection. |
| class SCEVUMaxExpr : public SCEVCommutativeExpr { |
| friend class ScalarEvolution; |
| |
| SCEVUMaxExpr(const FoldingSetNodeIDRef ID, |
| const SCEV *const *O, size_t N) |
| : SCEVCommutativeExpr(ID, scUMaxExpr, O, N) { |
| // Max never overflows. |
| setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW)); |
| } |
| |
| public: |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scUMaxExpr; |
| } |
| }; |
| |
| /// This means that we are dealing with an entirely unknown SCEV |
| /// value, and only represent it as its LLVM Value. This is the |
| /// "bottom" value for the analysis. |
| class SCEVUnknown final : public SCEV, private CallbackVH { |
| friend class ScalarEvolution; |
| |
| /// The parent ScalarEvolution value. This is used to update the |
| /// parent's maps when the value associated with a SCEVUnknown is |
| /// deleted or RAUW'd. |
| ScalarEvolution *SE; |
| |
| /// The next pointer in the linked list of all SCEVUnknown |
| /// instances owned by a ScalarEvolution. |
| SCEVUnknown *Next; |
| |
| SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V, |
| ScalarEvolution *se, SCEVUnknown *next) : |
| SCEV(ID, scUnknown, 1), CallbackVH(V), SE(se), Next(next) {} |
| |
| // Implement CallbackVH. |
| void deleted() override; |
| void allUsesReplacedWith(Value *New) override; |
| |
| public: |
| Value *getValue() const { return getValPtr(); } |
| |
| /// @{ |
| /// Test whether this is a special constant representing a type |
| /// size, alignment, or field offset in a target-independent |
| /// manner, and hasn't happened to have been folded with other |
| /// operations into something unrecognizable. This is mainly only |
| /// useful for pretty-printing and other situations where it isn't |
| /// absolutely required for these to succeed. |
| bool isSizeOf(Type *&AllocTy) const; |
| bool isAlignOf(Type *&AllocTy) const; |
| bool isOffsetOf(Type *&STy, Constant *&FieldNo) const; |
| /// @} |
| |
| Type *getType() const { return getValPtr()->getType(); } |
| |
| /// Methods for support type inquiry through isa, cast, and dyn_cast: |
| static bool classof(const SCEV *S) { |
| return S->getSCEVType() == scUnknown; |
| } |
| }; |
| |
| /// This class defines a simple visitor class that may be used for |
| /// various SCEV analysis purposes. |
| template<typename SC, typename RetVal=void> |
| struct SCEVVisitor { |
| RetVal visit(const SCEV *S) { |
| switch (S->getSCEVType()) { |
| case scConstant: |
| return ((SC*)this)->visitConstant((const SCEVConstant*)S); |
| case scTruncate: |
| return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S); |
| case scZeroExtend: |
| return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S); |
| case scSignExtend: |
| return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S); |
| case scAddExpr: |
| return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S); |
| case scMulExpr: |
| return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S); |
| case scUDivExpr: |
| return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S); |
| case scAddRecExpr: |
| return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S); |
| case scSMaxExpr: |
| return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S); |
| case scUMaxExpr: |
| return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S); |
| case scUnknown: |
| return ((SC*)this)->visitUnknown((const SCEVUnknown*)S); |
| case scCouldNotCompute: |
| return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S); |
| default: |
| llvm_unreachable("Unknown SCEV type!"); |
| } |
| } |
| |
| RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) { |
| llvm_unreachable("Invalid use of SCEVCouldNotCompute!"); |
| } |
| }; |
| |
| /// Visit all nodes in the expression tree using worklist traversal. |
| /// |
| /// Visitor implements: |
| /// // return true to follow this node. |
| /// bool follow(const SCEV *S); |
| /// // return true to terminate the search. |
| /// bool isDone(); |
| template<typename SV> |
| class SCEVTraversal { |
| SV &Visitor; |
| SmallVector<const SCEV *, 8> Worklist; |
| SmallPtrSet<const SCEV *, 8> Visited; |
| |
| void push(const SCEV *S) { |
| if (Visited.insert(S).second && Visitor.follow(S)) |
| Worklist.push_back(S); |
| } |
| |
| public: |
| SCEVTraversal(SV& V): Visitor(V) {} |
| |
| void visitAll(const SCEV *Root) { |
| push(Root); |
| while (!Worklist.empty() && !Visitor.isDone()) { |
| const SCEV *S = Worklist.pop_back_val(); |
| |
| switch (S->getSCEVType()) { |
| case scConstant: |
| case scUnknown: |
| break; |
| case scTruncate: |
| case scZeroExtend: |
| case scSignExtend: |
| push(cast<SCEVCastExpr>(S)->getOperand()); |
| break; |
| case scAddExpr: |
| case scMulExpr: |
| case scSMaxExpr: |
| case scUMaxExpr: |
| case scAddRecExpr: |
| for (const auto *Op : cast<SCEVNAryExpr>(S)->operands()) |
| push(Op); |
| break; |
| case scUDivExpr: { |
| const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S); |
| push(UDiv->getLHS()); |
| push(UDiv->getRHS()); |
| break; |
| } |
| case scCouldNotCompute: |
| llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!"); |
| default: |
| llvm_unreachable("Unknown SCEV kind!"); |
| } |
| } |
| } |
| }; |
| |
| /// Use SCEVTraversal to visit all nodes in the given expression tree. |
| template<typename SV> |
| void visitAll(const SCEV *Root, SV& Visitor) { |
| SCEVTraversal<SV> T(Visitor); |
| T.visitAll(Root); |
| } |
| |
| /// Return true if any node in \p Root satisfies the predicate \p Pred. |
| template <typename PredTy> |
| bool SCEVExprContains(const SCEV *Root, PredTy Pred) { |
| struct FindClosure { |
| bool Found = false; |
| PredTy Pred; |
| |
| FindClosure(PredTy Pred) : Pred(Pred) {} |
| |
| bool follow(const SCEV *S) { |
| if (!Pred(S)) |
| return true; |
| |
| Found = true; |
| return false; |
| } |
| |
| bool isDone() const { return Found; } |
| }; |
| |
| FindClosure FC(Pred); |
| visitAll(Root, FC); |
| return FC.Found; |
| } |
| |
| /// This visitor recursively visits a SCEV expression and re-writes it. |
| /// The result from each visit is cached, so it will return the same |
| /// SCEV for the same input. |
| template<typename SC> |
| class SCEVRewriteVisitor : public SCEVVisitor<SC, const SCEV *> { |
| protected: |
| ScalarEvolution &SE; |
| // Memoize the result of each visit so that we only compute once for |
| // the same input SCEV. This is to avoid redundant computations when |
| // a SCEV is referenced by multiple SCEVs. Without memoization, this |
| // visit algorithm would have exponential time complexity in the worst |
| // case, causing the compiler to hang on certain tests. |
| DenseMap<const SCEV *, const SCEV *> RewriteResults; |
| |
| public: |
| SCEVRewriteVisitor(ScalarEvolution &SE) : SE(SE) {} |
| |
| const SCEV *visit(const SCEV *S) { |
| auto It = RewriteResults.find(S); |
| if (It != RewriteResults.end()) |
| return It->second; |
| auto* Visited = SCEVVisitor<SC, const SCEV *>::visit(S); |
| auto Result = RewriteResults.try_emplace(S, Visited); |
| assert(Result.second && "Should insert a new entry"); |
| return Result.first->second; |
| } |
| |
| const SCEV *visitConstant(const SCEVConstant *Constant) { |
| return Constant; |
| } |
| |
| const SCEV *visitTruncateExpr(const SCEVTruncateExpr *Expr) { |
| const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand()); |
| return Operand == Expr->getOperand() |
| ? Expr |
| : SE.getTruncateExpr(Operand, Expr->getType()); |
| } |
| |
| const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) { |
| const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand()); |
| return Operand == Expr->getOperand() |
| ? Expr |
| : SE.getZeroExtendExpr(Operand, Expr->getType()); |
| } |
| |
| const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) { |
| const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand()); |
| return Operand == Expr->getOperand() |
| ? Expr |
| : SE.getSignExtendExpr(Operand, Expr->getType()); |
| } |
| |
| const SCEV *visitAddExpr(const SCEVAddExpr *Expr) { |
| SmallVector<const SCEV *, 2> Operands; |
| bool Changed = false; |
| for (auto *Op : Expr->operands()) { |
| Operands.push_back(((SC*)this)->visit(Op)); |
| Changed |= Op != Operands.back(); |
| } |
| return !Changed ? Expr : SE.getAddExpr(Operands); |
| } |
| |
| const SCEV *visitMulExpr(const SCEVMulExpr *Expr) { |
| SmallVector<const SCEV *, 2> Operands; |
| bool Changed = false; |
| for (auto *Op : Expr->operands()) { |
| Operands.push_back(((SC*)this)->visit(Op)); |
| Changed |= Op != Operands.back(); |
| } |
| return !Changed ? Expr : SE.getMulExpr(Operands); |
| } |
| |
| const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) { |
| auto *LHS = ((SC *)this)->visit(Expr->getLHS()); |
| auto *RHS = ((SC *)this)->visit(Expr->getRHS()); |
| bool Changed = LHS != Expr->getLHS() || RHS != Expr->getRHS(); |
| return !Changed ? Expr : SE.getUDivExpr(LHS, RHS); |
| } |
| |
| const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { |
| SmallVector<const SCEV *, 2> Operands; |
| bool Changed = false; |
| for (auto *Op : Expr->operands()) { |
| Operands.push_back(((SC*)this)->visit(Op)); |
| Changed |= Op != Operands.back(); |
| } |
| return !Changed ? Expr |
| : SE.getAddRecExpr(Operands, Expr->getLoop(), |
| Expr->getNoWrapFlags()); |
| } |
| |
| const SCEV *visitSMaxExpr(const SCEVSMaxExpr *Expr) { |
| SmallVector<const SCEV *, 2> Operands; |
| bool Changed = false; |
| for (auto *Op : Expr->operands()) { |
| Operands.push_back(((SC *)this)->visit(Op)); |
| Changed |= Op != Operands.back(); |
| } |
| return !Changed ? Expr : SE.getSMaxExpr(Operands); |
| } |
| |
| const SCEV *visitUMaxExpr(const SCEVUMaxExpr *Expr) { |
| SmallVector<const SCEV *, 2> Operands; |
| bool Changed = false; |
| for (auto *Op : Expr->operands()) { |
| Operands.push_back(((SC*)this)->visit(Op)); |
| Changed |= Op != Operands.back(); |
| } |
| return !Changed ? Expr : SE.getUMaxExpr(Operands); |
| } |
| |
| const SCEV *visitUnknown(const SCEVUnknown *Expr) { |
| return Expr; |
| } |
| |
| const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) { |
| return Expr; |
| } |
| }; |
| |
| using ValueToValueMap = DenseMap<const Value *, Value *>; |
| |
| /// The SCEVParameterRewriter takes a scalar evolution expression and updates |
| /// the SCEVUnknown components following the Map (Value -> Value). |
| class SCEVParameterRewriter : public SCEVRewriteVisitor<SCEVParameterRewriter> { |
| public: |
| static const SCEV *rewrite(const SCEV *Scev, ScalarEvolution &SE, |
| ValueToValueMap &Map, |
| bool InterpretConsts = false) { |
| SCEVParameterRewriter Rewriter(SE, Map, InterpretConsts); |
| return Rewriter.visit(Scev); |
| } |
| |
| SCEVParameterRewriter(ScalarEvolution &SE, ValueToValueMap &M, bool C) |
| : SCEVRewriteVisitor(SE), Map(M), InterpretConsts(C) {} |
| |
| const SCEV *visitUnknown(const SCEVUnknown *Expr) { |
| Value *V = Expr->getValue(); |
| if (Map.count(V)) { |
| Value *NV = Map[V]; |
| if (InterpretConsts && isa<ConstantInt>(NV)) |
| return SE.getConstant(cast<ConstantInt>(NV)); |
| return SE.getUnknown(NV); |
| } |
| return Expr; |
| } |
| |
| private: |
| ValueToValueMap ⤅ |
| bool InterpretConsts; |
| }; |
| |
| using LoopToScevMapT = DenseMap<const Loop *, const SCEV *>; |
| |
| /// The SCEVLoopAddRecRewriter takes a scalar evolution expression and applies |
| /// the Map (Loop -> SCEV) to all AddRecExprs. |
| class SCEVLoopAddRecRewriter |
| : public SCEVRewriteVisitor<SCEVLoopAddRecRewriter> { |
| public: |
| SCEVLoopAddRecRewriter(ScalarEvolution &SE, LoopToScevMapT &M) |
| : SCEVRewriteVisitor(SE), Map(M) {} |
| |
| static const SCEV *rewrite(const SCEV *Scev, LoopToScevMapT &Map, |
| ScalarEvolution &SE) { |
| SCEVLoopAddRecRewriter Rewriter(SE, Map); |
| return Rewriter.visit(Scev); |
| } |
| |
| const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { |
| SmallVector<const SCEV *, 2> Operands; |
| for (const SCEV *Op : Expr->operands()) |
| Operands.push_back(visit(Op)); |
| |
| const Loop *L = Expr->getLoop(); |
| const SCEV *Res = SE.getAddRecExpr(Operands, L, Expr->getNoWrapFlags()); |
| |
| if (0 == Map.count(L)) |
| return Res; |
| |
| const SCEVAddRecExpr *Rec = cast<SCEVAddRecExpr>(Res); |
| return Rec->evaluateAtIteration(Map[L], SE); |
| } |
| |
| private: |
| LoopToScevMapT ⤅ |
| }; |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H |