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492 lines
18 KiB
C++
492 lines
18 KiB
C++
//===- llvm/Analysis/ScalarEvolutionExpressions.h - SCEV Exprs --*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the classes used to represent and build scalar expressions.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
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#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
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#include "llvm/Analysis/ScalarEvolution.h"
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#include "llvm/Support/ErrorHandling.h"
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namespace llvm {
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class ConstantInt;
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class ConstantRange;
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class DominatorTree;
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enum SCEVTypes {
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// These should be ordered in terms of increasing complexity to make the
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// folders simpler.
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scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr,
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scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr,
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scUnknown, scCouldNotCompute
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};
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//===--------------------------------------------------------------------===//
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/// SCEVConstant - This class represents a constant integer value.
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///
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class SCEVConstant : public SCEV {
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friend class ScalarEvolution;
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ConstantInt *V;
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SCEVConstant(const FoldingSetNodeIDRef ID, ConstantInt *v) :
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SCEV(ID, scConstant), V(v) {}
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public:
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ConstantInt *getValue() const { return V; }
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const Type *getType() const { return V->getType(); }
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVConstant *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scConstant;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVCastExpr - This is the base class for unary cast operator classes.
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///
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class SCEVCastExpr : public SCEV {
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protected:
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const SCEV *Op;
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const Type *Ty;
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SCEVCastExpr(const FoldingSetNodeIDRef ID,
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unsigned SCEVTy, const SCEV *op, const Type *ty);
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public:
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const SCEV *getOperand() const { return Op; }
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const Type *getType() const { return Ty; }
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVCastExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scTruncate ||
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S->getSCEVType() == scZeroExtend ||
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S->getSCEVType() == scSignExtend;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVTruncateExpr - This class represents a truncation of an integer value
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/// to a smaller integer value.
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///
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class SCEVTruncateExpr : public SCEVCastExpr {
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friend class ScalarEvolution;
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SCEVTruncateExpr(const FoldingSetNodeIDRef ID,
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const SCEV *op, const Type *ty);
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public:
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVTruncateExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scTruncate;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVZeroExtendExpr - This class represents a zero extension of a small
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/// integer value to a larger integer value.
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///
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class SCEVZeroExtendExpr : public SCEVCastExpr {
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friend class ScalarEvolution;
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SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
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const SCEV *op, const Type *ty);
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public:
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVZeroExtendExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scZeroExtend;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVSignExtendExpr - This class represents a sign extension of a small
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/// integer value to a larger integer value.
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///
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class SCEVSignExtendExpr : public SCEVCastExpr {
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friend class ScalarEvolution;
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SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
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const SCEV *op, const Type *ty);
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public:
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVSignExtendExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scSignExtend;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVNAryExpr - This node is a base class providing common
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/// functionality for n'ary operators.
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///
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class SCEVNAryExpr : public SCEV {
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protected:
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// Since SCEVs are immutable, ScalarEvolution allocates operand
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// arrays with its SCEVAllocator, so this class just needs a simple
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// pointer rather than a more elaborate vector-like data structure.
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// This also avoids the need for a non-trivial destructor.
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const SCEV *const *Operands;
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size_t NumOperands;
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SCEVNAryExpr(const FoldingSetNodeIDRef ID,
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enum SCEVTypes T, const SCEV *const *O, size_t N)
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: SCEV(ID, T), Operands(O), NumOperands(N) {}
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public:
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size_t getNumOperands() const { return NumOperands; }
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const SCEV *getOperand(unsigned i) const {
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assert(i < NumOperands && "Operand index out of range!");
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return Operands[i];
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}
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typedef const SCEV *const *op_iterator;
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op_iterator op_begin() const { return Operands; }
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op_iterator op_end() const { return Operands + NumOperands; }
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const Type *getType() const { return getOperand(0)->getType(); }
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bool hasNoUnsignedWrap() const { return SubclassData & (1 << 0); }
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void setHasNoUnsignedWrap(bool B) {
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SubclassData = (SubclassData & ~(1 << 0)) | (B << 0);
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}
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bool hasNoSignedWrap() const { return SubclassData & (1 << 1); }
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void setHasNoSignedWrap(bool B) {
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SubclassData = (SubclassData & ~(1 << 1)) | (B << 1);
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}
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVNAryExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scAddExpr ||
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S->getSCEVType() == scMulExpr ||
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S->getSCEVType() == scSMaxExpr ||
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S->getSCEVType() == scUMaxExpr ||
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S->getSCEVType() == scAddRecExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVCommutativeExpr - This node is the base class for n'ary commutative
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/// operators.
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///
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class SCEVCommutativeExpr : public SCEVNAryExpr {
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protected:
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SCEVCommutativeExpr(const FoldingSetNodeIDRef ID,
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enum SCEVTypes T, const SCEV *const *O, size_t N)
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: SCEVNAryExpr(ID, T, O, N) {}
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public:
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVCommutativeExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scAddExpr ||
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S->getSCEVType() == scMulExpr ||
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S->getSCEVType() == scSMaxExpr ||
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S->getSCEVType() == scUMaxExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVAddExpr - This node represents an addition of some number of SCEVs.
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///
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class SCEVAddExpr : public SCEVCommutativeExpr {
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friend class ScalarEvolution;
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SCEVAddExpr(const FoldingSetNodeIDRef ID,
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const SCEV *const *O, size_t N)
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: SCEVCommutativeExpr(ID, scAddExpr, O, N) {
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}
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public:
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const Type *getType() const {
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// Use the type of the last operand, which is likely to be a pointer
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// type, if there is one. This doesn't usually matter, but it can help
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// reduce casts when the expressions are expanded.
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return getOperand(getNumOperands() - 1)->getType();
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}
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVAddExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scAddExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
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///
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class SCEVMulExpr : public SCEVCommutativeExpr {
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friend class ScalarEvolution;
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SCEVMulExpr(const FoldingSetNodeIDRef ID,
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const SCEV *const *O, size_t N)
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: SCEVCommutativeExpr(ID, scMulExpr, O, N) {
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}
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public:
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVMulExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scMulExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVUDivExpr - This class represents a binary unsigned division operation.
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///
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class SCEVUDivExpr : public SCEV {
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friend class ScalarEvolution;
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const SCEV *LHS;
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const SCEV *RHS;
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SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs)
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: SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {}
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public:
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const SCEV *getLHS() const { return LHS; }
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const SCEV *getRHS() const { return RHS; }
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const Type *getType() const {
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// In most cases the types of LHS and RHS will be the same, but in some
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// crazy cases one or the other may be a pointer. ScalarEvolution doesn't
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// depend on the type for correctness, but handling types carefully can
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// avoid extra casts in the SCEVExpander. The LHS is more likely to be
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// a pointer type than the RHS, so use the RHS' type here.
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return getRHS()->getType();
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}
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVUDivExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scUDivExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
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/// count of the specified loop. This is the primary focus of the
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/// ScalarEvolution framework; all the other SCEV subclasses are mostly just
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/// supporting infrastructure to allow SCEVAddRecExpr expressions to be
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/// created and analyzed.
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///
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/// All operands of an AddRec are required to be loop invariant.
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///
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class SCEVAddRecExpr : public SCEVNAryExpr {
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friend class ScalarEvolution;
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const Loop *L;
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SCEVAddRecExpr(const FoldingSetNodeIDRef ID,
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const SCEV *const *O, size_t N, const Loop *l)
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: SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {}
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public:
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const SCEV *getStart() const { return Operands[0]; }
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const Loop *getLoop() const { return L; }
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/// getStepRecurrence - This method constructs and returns the recurrence
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/// indicating how much this expression steps by. If this is a polynomial
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/// of degree N, it returns a chrec of degree N-1.
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const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
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if (isAffine()) return getOperand(1);
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return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
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op_end()),
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getLoop());
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}
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/// isAffine - Return true if this is an affine AddRec (i.e., it represents
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/// an expressions A+B*x where A and B are loop invariant values.
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bool isAffine() const {
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// We know that the start value is invariant. This expression is thus
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// affine iff the step is also invariant.
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return getNumOperands() == 2;
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}
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/// isQuadratic - Return true if this is an quadratic AddRec (i.e., it
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/// represents an expressions A+B*x+C*x^2 where A, B and C are loop
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/// invariant values. This corresponds to an addrec of the form {L,+,M,+,N}
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bool isQuadratic() const {
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return getNumOperands() == 3;
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}
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/// evaluateAtIteration - Return the value of this chain of recurrences at
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/// the specified iteration number.
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const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;
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/// getNumIterationsInRange - Return the number of iterations of this loop
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/// that produce values in the specified constant range. Another way of
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/// looking at this is that it returns the first iteration number where the
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/// value is not in the condition, thus computing the exit count. If the
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/// iteration count can't be computed, an instance of SCEVCouldNotCompute is
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/// returned.
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const SCEV *getNumIterationsInRange(ConstantRange Range,
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ScalarEvolution &SE) const;
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/// getPostIncExpr - Return an expression representing the value of
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/// this expression one iteration of the loop ahead.
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const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const {
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return cast<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
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}
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVAddRecExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scAddRecExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVSMaxExpr - This class represents a signed maximum selection.
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///
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class SCEVSMaxExpr : public SCEVCommutativeExpr {
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friend class ScalarEvolution;
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SCEVSMaxExpr(const FoldingSetNodeIDRef ID,
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const SCEV *const *O, size_t N)
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: SCEVCommutativeExpr(ID, scSMaxExpr, O, N) {
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// Max never overflows.
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setHasNoUnsignedWrap(true);
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setHasNoSignedWrap(true);
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}
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public:
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVSMaxExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scSMaxExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVUMaxExpr - This class represents an unsigned maximum selection.
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///
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class SCEVUMaxExpr : public SCEVCommutativeExpr {
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friend class ScalarEvolution;
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SCEVUMaxExpr(const FoldingSetNodeIDRef ID,
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const SCEV *const *O, size_t N)
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: SCEVCommutativeExpr(ID, scUMaxExpr, O, N) {
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// Max never overflows.
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setHasNoUnsignedWrap(true);
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setHasNoSignedWrap(true);
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}
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public:
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVUMaxExpr *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scUMaxExpr;
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}
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};
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//===--------------------------------------------------------------------===//
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/// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
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/// value, and only represent it as its LLVM Value. This is the "bottom"
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/// value for the analysis.
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///
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class SCEVUnknown : public SCEV, private CallbackVH {
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friend class ScalarEvolution;
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// Implement CallbackVH.
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virtual void deleted();
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virtual void allUsesReplacedWith(Value *New);
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/// SE - The parent ScalarEvolution value. This is used to update
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/// the parent's maps when the value associated with a SCEVUnknown
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/// is deleted or RAUW'd.
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ScalarEvolution *SE;
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/// Next - The next pointer in the linked list of all
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/// SCEVUnknown instances owned by a ScalarEvolution.
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SCEVUnknown *Next;
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SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V,
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ScalarEvolution *se, SCEVUnknown *next) :
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SCEV(ID, scUnknown), CallbackVH(V), SE(se), Next(next) {}
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public:
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Value *getValue() const { return getValPtr(); }
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/// isSizeOf, isAlignOf, isOffsetOf - Test whether this is a special
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/// constant representing a type size, alignment, or field offset in
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/// a target-independent manner, and hasn't happened to have been
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/// folded with other operations into something unrecognizable. This
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/// is mainly only useful for pretty-printing and other situations
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/// where it isn't absolutely required for these to succeed.
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bool isSizeOf(const Type *&AllocTy) const;
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bool isAlignOf(const Type *&AllocTy) const;
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bool isOffsetOf(const Type *&STy, Constant *&FieldNo) const;
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const Type *getType() const { return getValPtr()->getType(); }
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const SCEVUnknown *S) { return true; }
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static inline bool classof(const SCEV *S) {
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return S->getSCEVType() == scUnknown;
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}
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};
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/// SCEVVisitor - This class defines a simple visitor class that may be used
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/// for various SCEV analysis purposes.
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template<typename SC, typename RetVal=void>
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struct SCEVVisitor {
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RetVal visit(const SCEV *S) {
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switch (S->getSCEVType()) {
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case scConstant:
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return ((SC*)this)->visitConstant((const SCEVConstant*)S);
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case scTruncate:
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return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
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case scZeroExtend:
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return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
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case scSignExtend:
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return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
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case scAddExpr:
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return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
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case scMulExpr:
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return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
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case scUDivExpr:
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return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
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case scAddRecExpr:
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return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
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case scSMaxExpr:
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return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
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case scUMaxExpr:
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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!");
|
|
return RetVal();
|
|
}
|
|
};
|
|
}
|
|
|
|
#endif
|