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+//===- llvm/Analysis/ScalarEvolutionExpressions.h - SCEV Exprs --*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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), 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;
+ }
+ };
+
+ /// 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), 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), 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), 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