llvm-6502/include/llvm/Analysis/ScalarEvolutionExpressions.h
Dan Gohman c93b4cff89 Add the ability to "intern" FoldingSetNodeID data into a
BumpPtrAllocator-allocated region to allow it to be stored in a more
compact form and to avoid the need for a non-trivial destructor call.

Use this new mechanism in ScalarEvolution instead of
FastFoldingSetNode to avoid leaking memory in the case where a
FoldingSetNodeID uses heap storage, and to reduce overall memory
usage.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98829 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-18 16:16:38 +00:00

610 lines
21 KiB
C++

//===- 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_SCALAREVOLUTION_EXPRESSIONS_H
#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Support/ErrorHandling.h"
namespace llvm {
class ConstantInt;
class ConstantRange;
class DominatorTree;
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
};
//===--------------------------------------------------------------------===//
/// SCEVConstant - 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; }
virtual bool isLoopInvariant(const Loop *L) const {
return true;
}
virtual bool hasComputableLoopEvolution(const Loop *L) const {
return false; // Not loop variant
}
virtual const Type *getType() const;
virtual bool hasOperand(const SCEV *) const {
return false;
}
bool dominates(BasicBlock *BB, DominatorTree *DT) const {
return true;
}
bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
return true;
}
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVConstant *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scConstant;
}
};
//===--------------------------------------------------------------------===//
/// SCEVCastExpr - This is the base class for unary cast operator classes.
///
class SCEVCastExpr : public SCEV {
protected:
const SCEV *Op;
const Type *Ty;
SCEVCastExpr(const FoldingSetNodeIDRef ID,
unsigned SCEVTy, const SCEV *op, const Type *ty);
public:
const SCEV *getOperand() const { return Op; }
virtual const Type *getType() const { return Ty; }
virtual bool isLoopInvariant(const Loop *L) const {
return Op->isLoopInvariant(L);
}
virtual bool hasComputableLoopEvolution(const Loop *L) const {
return Op->hasComputableLoopEvolution(L);
}
virtual bool hasOperand(const SCEV *O) const {
return Op == O || Op->hasOperand(O);
}
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const;
virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVCastExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scTruncate ||
S->getSCEVType() == scZeroExtend ||
S->getSCEVType() == scSignExtend;
}
};
//===--------------------------------------------------------------------===//
/// SCEVTruncateExpr - 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, const Type *ty);
public:
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVTruncateExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scTruncate;
}
};
//===--------------------------------------------------------------------===//
/// SCEVZeroExtendExpr - 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, const Type *ty);
public:
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVZeroExtendExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scZeroExtend;
}
};
//===--------------------------------------------------------------------===//
/// SCEVSignExtendExpr - 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, const Type *ty);
public:
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVSignExtendExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scSignExtend;
}
};
//===--------------------------------------------------------------------===//
/// SCEVNAryExpr - 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];
}
typedef const SCEV *const *op_iterator;
op_iterator op_begin() const { return Operands; }
op_iterator op_end() const { return Operands + NumOperands; }
virtual bool isLoopInvariant(const Loop *L) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
if (!getOperand(i)->isLoopInvariant(L)) return false;
return true;
}
// hasComputableLoopEvolution - N-ary expressions have computable loop
// evolutions iff they have at least one operand that varies with the loop,
// but that all varying operands are computable.
virtual bool hasComputableLoopEvolution(const Loop *L) const {
bool HasVarying = false;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
if (!getOperand(i)->isLoopInvariant(L)) {
if (getOperand(i)->hasComputableLoopEvolution(L))
HasVarying = true;
else
return false;
}
return HasVarying;
}
virtual bool hasOperand(const SCEV *O) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
if (O == getOperand(i) || getOperand(i)->hasOperand(O))
return true;
return false;
}
bool dominates(BasicBlock *BB, DominatorTree *DT) const;
bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
virtual const Type *getType() const { return getOperand(0)->getType(); }
bool hasNoUnsignedWrap() const { return SubclassData & (1 << 0); }
void setHasNoUnsignedWrap(bool B) {
SubclassData = (SubclassData & ~(1 << 0)) | (B << 0);
}
bool hasNoSignedWrap() const { return SubclassData & (1 << 1); }
void setHasNoSignedWrap(bool B) {
SubclassData = (SubclassData & ~(1 << 1)) | (B << 1);
}
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVNAryExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scAddExpr ||
S->getSCEVType() == scMulExpr ||
S->getSCEVType() == scSMaxExpr ||
S->getSCEVType() == scUMaxExpr ||
S->getSCEVType() == scAddRecExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVCommutativeExpr - 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:
virtual const char *getOperationStr() const = 0;
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVCommutativeExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scAddExpr ||
S->getSCEVType() == scMulExpr ||
S->getSCEVType() == scSMaxExpr ||
S->getSCEVType() == scUMaxExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVAddExpr - 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:
virtual const char *getOperationStr() const { return " + "; }
virtual const 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 inline bool classof(const SCEVAddExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scAddExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVMulExpr - 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:
virtual const char *getOperationStr() const { return " * "; }
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVMulExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scMulExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVUDivExpr - 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; }
virtual bool isLoopInvariant(const Loop *L) const {
return LHS->isLoopInvariant(L) && RHS->isLoopInvariant(L);
}
virtual bool hasComputableLoopEvolution(const Loop *L) const {
return LHS->hasComputableLoopEvolution(L) &&
RHS->hasComputableLoopEvolution(L);
}
virtual bool hasOperand(const SCEV *O) const {
return O == LHS || O == RHS || LHS->hasOperand(O) || RHS->hasOperand(O);
}
bool dominates(BasicBlock *BB, DominatorTree *DT) const;
bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
virtual const Type *getType() const;
void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVUDivExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scUDivExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVAddRecExpr - 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) {
for (size_t i = 0, e = NumOperands; i != e; ++i)
assert(Operands[i]->isLoopInvariant(l) &&
"Operands of AddRec must be loop-invariant!");
}
public:
const SCEV *getStart() const { return Operands[0]; }
const Loop *getLoop() const { return L; }
/// getStepRecurrence - This method 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.
const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
if (isAffine()) return getOperand(1);
return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
op_end()),
getLoop());
}
virtual bool hasComputableLoopEvolution(const Loop *QL) const {
return L == QL;
}
virtual bool isLoopInvariant(const Loop *QueryLoop) const;
bool dominates(BasicBlock *BB, DominatorTree *DT) const;
bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
/// isAffine - Return true if this is an affine AddRec (i.e., it represents
/// an expressions 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;
}
/// isQuadratic - Return true if this is an quadratic AddRec (i.e., it
/// represents an expressions 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;
}
/// evaluateAtIteration - Return the value of this chain of recurrences at
/// the specified iteration number.
const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;
/// getNumIterationsInRange - 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(ConstantRange Range,
ScalarEvolution &SE) const;
/// getPostIncExpr - Return an expression representing the value of
/// this expression one iteration of the loop ahead.
const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const {
return cast<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
}
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVAddRecExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scAddRecExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVSMaxExpr - 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.
setHasNoUnsignedWrap(true);
setHasNoSignedWrap(true);
}
public:
virtual const char *getOperationStr() const { return " smax "; }
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVSMaxExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scSMaxExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVUMaxExpr - 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.
setHasNoUnsignedWrap(true);
setHasNoSignedWrap(true);
}
public:
virtual const char *getOperationStr() const { return " umax "; }
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVUMaxExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scUMaxExpr;
}
};
//===--------------------------------------------------------------------===//
/// SCEVUnknown - 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 : public SCEV {
friend class ScalarEvolution;
Value *V;
SCEVUnknown(const FoldingSetNodeIDRef ID, Value *v) :
SCEV(ID, scUnknown), V(v) {}
public:
Value *getValue() const { return V; }
/// isSizeOf, isAlignOf, isOffsetOf - 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(const Type *&AllocTy) const;
bool isAlignOf(const Type *&AllocTy) const;
bool isOffsetOf(const Type *&STy, Constant *&FieldNo) const;
virtual bool isLoopInvariant(const Loop *L) const;
virtual bool hasComputableLoopEvolution(const Loop *QL) const {
return false; // not computable
}
virtual bool hasOperand(const SCEV *) const {
return false;
}
bool dominates(BasicBlock *BB, DominatorTree *DT) const;
bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
virtual const Type *getType() const;
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVUnknown *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scUnknown;
}
};
/// SCEVVisitor - 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!");
return RetVal();
}
};
}
#endif