//===----------------------------------------------------------------------===//
//
// The ScalarEvolution class is an LLVM pass which can be used to analyze and
-// catagorize scalar expressions in loops. It specializes in recognizing
+// categorize scalar expressions in loops. It specializes in recognizing
// general induction variables, representing them with the abstract and opaque
// SCEV class. Given this analysis, trip counts of loops and other important
// properties can be obtained.
#include "llvm/Pass.h"
#include "llvm/Instructions.h"
-#include "llvm/Support/DataTypes.h"
+#include "llvm/Function.h"
+#include "llvm/System/DataTypes.h"
#include "llvm/Support/ValueHandle.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/DenseMap.h"
-#include <iosfwd>
#include <map>
namespace llvm {
class LLVMContext;
class Loop;
class LoopInfo;
+ class Operator;
+ class SCEVUnknown;
/// SCEV - This class represents an analyzed expression in the program. These
/// are opaque objects that the client is not allowed to do much with
/// directly.
///
- class SCEV : public FastFoldingSetNode {
- const unsigned SCEVType; // The SCEV baseclass this node corresponds to
+ class SCEV : public FoldingSetNode {
+ /// FastID - A reference to an Interned FoldingSetNodeID for this node.
+ /// The ScalarEvolution's BumpPtrAllocator holds the data.
+ FoldingSetNodeIDRef FastID;
+ // The SCEV baseclass this node corresponds to
+ const unsigned short SCEVType;
+
+ protected:
+ /// SubclassData - This field is initialized to zero and may be used in
+ /// subclasses to store miscellaneous information.
+ unsigned short SubclassData;
+
+ private:
SCEV(const SCEV &); // DO NOT IMPLEMENT
void operator=(const SCEV &); // DO NOT IMPLEMENT
protected:
virtual ~SCEV();
public:
- explicit SCEV(const FoldingSetNodeID &ID, unsigned SCEVTy) :
- FastFoldingSetNode(ID), SCEVType(SCEVTy) {}
+ explicit SCEV(const FoldingSetNodeIDRef ID, unsigned SCEVTy) :
+ FastID(ID), SCEVType(SCEVTy), SubclassData(0) {}
unsigned getSCEVType() const { return SCEVType; }
+ /// Profile - FoldingSet support.
+ void Profile(FoldingSetNodeID& ID) { ID = FastID; }
+
/// isLoopInvariant - Return true if the value of this SCEV is unchanging in
/// the specified loop.
virtual bool isLoopInvariant(const Loop *L) const = 0;
///
bool isAllOnesValue() const;
- /// replaceSymbolicValuesWithConcrete - If this SCEV internally references
- /// the symbolic value "Sym", construct and return a new SCEV that produces
- /// the same value, but which uses the concrete value Conc instead of the
- /// symbolic value. If this SCEV does not use the symbolic value, it
- /// returns itself.
- virtual const SCEV *
- replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const = 0;
+ /// hasOperand - Test whether this SCEV has Op as a direct or
+ /// indirect operand.
+ virtual bool hasOperand(const SCEV *Op) const = 0;
/// dominates - Return true if elements that makes up this SCEV dominates
/// the specified basic block.
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const = 0;
+ /// properlyDominates - Return true if elements that makes up this SCEV
+ /// properly dominate the specified basic block.
+ virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const = 0;
+
/// print - Print out the internal representation of this scalar to the
/// specified stream. This should really only be used for debugging
/// purposes.
virtual void print(raw_ostream &OS) const = 0;
- void print(std::ostream &OS) const;
- void print(std::ostream *OS) const { if (OS) print(*OS); }
/// dump - This method is used for debugging.
///
return OS;
}
- inline std::ostream &operator<<(std::ostream &OS, const SCEV &S) {
- S.print(OS);
- return OS;
- }
-
/// SCEVCouldNotCompute - An object of this class is returned by queries that
/// could not be answered. For example, if you ask for the number of
/// iterations of a linked-list traversal loop, you will get one of these.
virtual const Type *getType() const;
virtual bool hasComputableLoopEvolution(const Loop *L) const;
virtual void print(raw_ostream &OS) const;
- virtual const SCEV *
- replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const;
+ virtual bool hasOperand(const SCEV *Op) const;
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const {
return true;
}
+ virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ return true;
+ }
+
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVCouldNotCompute *S) { return true; }
static bool classof(const SCEV *S);
};
friend class SCEVCallbackVH;
- friend struct SCEVExpander;
+ friend class SCEVExpander;
+ friend class SCEVUnknown;
/// F - The function we are analyzing.
///
///
LoopInfo *LI;
- /// TD - The target data information for the target we are targetting.
+ /// TD - The target data information for the target we are targeting.
///
TargetData *TD;
+ /// DT - The dominator tree.
+ ///
+ DominatorTree *DT;
+
/// CouldNotCompute - This SCEV is used to represent unknown trip
/// counts and things.
SCEVCouldNotCompute CouldNotCompute;
std::map<SCEVCallbackVH, const SCEV *> Scalars;
/// BackedgeTakenInfo - Information about the backedge-taken count
- /// of a loop. This currently inclues an exact count and a maximum count.
+ /// of a loop. This currently includes an exact count and a maximum count.
///
struct BackedgeTakenInfo {
/// Exact - An expression indicating the exact backedge-taken count of
/// exit value.
std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue;
- /// ValuesAtScopes - This map contains entries for all the instructions
- /// that we attempt to compute getSCEVAtScope information for without
- /// using SCEV techniques, which can be expensive.
- std::map<Instruction *, std::map<const Loop *, Constant *> > ValuesAtScopes;
+ /// ValuesAtScopes - This map contains entries for all the expressions
+ /// that we attempt to compute getSCEVAtScope information for, which can
+ /// be expensive in extreme cases.
+ std::map<const SCEV *,
+ std::map<const Loop *, const SCEV *> > ValuesAtScopes;
/// createSCEV - We know that there is no SCEV for the specified value.
/// Analyze the expression.
/// createNodeForGEP - Provide the special handling we need to analyze GEP
/// SCEVs.
- const SCEV *createNodeForGEP(User *GEP);
+ const SCEV *createNodeForGEP(GEPOperator *GEP);
+
+ /// computeSCEVAtScope - Implementation code for getSCEVAtScope; called
+ /// at most once for each SCEV+Loop pair.
+ ///
+ const SCEV *computeSCEVAtScope(const SCEV *S, const Loop *L);
- /// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value
- /// for the specified instruction and replaces any references to the
- /// symbolic value SymName with the specified value. This is used during
- /// PHI resolution.
- void ReplaceSymbolicValueWithConcrete(Instruction *I,
- const SCEV *SymName,
- const SCEV *NewVal);
+ /// ForgetSymbolicValue - This looks up computed SCEV values for all
+ /// instructions that depend on the given instruction and removes them from
+ /// the Scalars map if they reference SymName. This is used during PHI
+ /// resolution.
+ void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
/// getBECount - Subtract the end and start values and divide by the step,
/// rounding up, to get the number of times the backedge is executed. Return
/// CouldNotCompute if an intermediate computation overflows.
const SCEV *getBECount(const SCEV *Start,
- const SCEV *End,
- const SCEV *Step);
+ const SCEV *End,
+ const SCEV *Step,
+ bool NoWrap);
/// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given
/// loop, lazily computing new values if the loop hasn't been analyzed
BasicBlock *FBB);
/// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition
- /// of 'icmp op load X, cst', try to see if we can compute the trip count.
- const SCEV *
+ /// of 'icmp op load X, cst', try to see if we can compute the
+ /// backedge-taken count.
+ BackedgeTakenInfo
ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI,
Constant *RHS,
const Loop *L,
ICmpInst::Predicate p);
- /// ComputeBackedgeTakenCountExhaustively - If the trip is known to execute
+ /// ComputeBackedgeTakenCountExhaustively - If the loop is known to execute
/// a constant number of times (the condition evolves only from constants),
/// try to evaluate a few iterations of the loop until we get the exit
/// condition gets a value of ExitWhen (true or false). If we cannot
- /// evaluate the trip count of the loop, return CouldNotCompute.
+ /// evaluate the backedge-taken count of the loop, return CouldNotCompute.
const SCEV *ComputeBackedgeTakenCountExhaustively(const Loop *L,
Value *Cond,
bool ExitWhen);
/// HowFarToZero - Return the number of times a backedge comparing the
/// specified value to zero will execute. If not computable, return
/// CouldNotCompute.
- const SCEV *HowFarToZero(const SCEV *V, const Loop *L);
+ BackedgeTakenInfo HowFarToZero(const SCEV *V, const Loop *L);
/// HowFarToNonZero - Return the number of times a backedge checking the
/// specified value for nonzero will execute. If not computable, return
/// CouldNotCompute.
- const SCEV *HowFarToNonZero(const SCEV *V, const Loop *L);
+ BackedgeTakenInfo HowFarToNonZero(const SCEV *V, const Loop *L);
/// HowManyLessThans - Return the number of times a backedge containing the
/// specified less-than comparison will execute. If not computable, return
BackedgeTakenInfo HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
const Loop *L, bool isSigned);
- /// getLoopPredecessor - If the given loop's header has exactly one unique
- /// predecessor outside the loop, return it. Otherwise return null.
- BasicBlock *getLoopPredecessor(const Loop *L);
-
/// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
/// (which may not be an immediate predecessor) which has exactly one
/// successor from which BB is reachable, or null if no such block is
/// found.
- BasicBlock* getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB);
-
- /// isNecessaryCond - Test whether the condition described by Pred, LHS,
- /// and RHS is a necessary condition for the given Cond value to evaluate
- /// to true.
- bool isNecessaryCond(Value *Cond, ICmpInst::Predicate Pred,
- const SCEV *LHS, const SCEV *RHS,
- bool Inverse);
-
- /// isNecessaryCondOperands - Test whether the condition described by Pred,
- /// LHS, and RHS is a necessary condition for the condition described by
- /// Pred, FoundLHS, and FoundRHS to evaluate to true.
- bool isNecessaryCondOperands(ICmpInst::Predicate Pred,
- const SCEV *LHS, const SCEV *RHS,
- const SCEV *FoundLHS, const SCEV *FoundRHS);
+ std::pair<BasicBlock *, BasicBlock *>
+ getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB);
+
+ /// isImpliedCond - Test whether the condition described by Pred, LHS,
+ /// and RHS is true whenever the given Cond value evaluates to true.
+ bool isImpliedCond(Value *Cond, ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ bool Inverse);
+
+ /// isImpliedCondOperands - Test whether the condition described by Pred,
+ /// LHS, and RHS is true whenever the condition described by Pred, FoundLHS,
+ /// and FoundRHS is true.
+ bool isImpliedCondOperands(ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ const SCEV *FoundLHS, const SCEV *FoundRHS);
+
+ /// isImpliedCondOperandsHelper - Test whether the condition described by
+ /// Pred, LHS, and RHS is true whenever the condition described by Pred,
+ /// FoundLHS, and FoundRHS is true.
+ bool isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ const SCEV *FoundLHS, const SCEV *FoundRHS);
/// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
/// in the header of its containing loop, we know the loop executes a
Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs,
const Loop *L);
+ /// isKnownPredicateWithRanges - Test if the given expression is known to
+ /// satisfy the condition described by Pred and the known constant ranges
+ /// of LHS and RHS.
+ ///
+ bool isKnownPredicateWithRanges(ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS);
+
public:
static char ID; // Pass identification, replacement for typeid
ScalarEvolution();
- LLVMContext *getContext() const { return Context; }
+ LLVMContext &getContext() const { return F->getContext(); }
/// isSCEVable - Test if values of the given type are analyzable within
/// the SCEV framework. This primarily includes integer types, and it
/// this is the pointer-sized integer type.
const Type *getEffectiveSCEVType(const Type *Ty) const;
- /// getSCEV - Return a SCEV expression handle for the full generality of the
+ /// getSCEV - Return a SCEV expression for the full generality of the
/// specified expression.
const SCEV *getSCEV(Value *V);
const SCEV *getZeroExtendExpr(const SCEV *Op, const Type *Ty);
const SCEV *getSignExtendExpr(const SCEV *Op, const Type *Ty);
const SCEV *getAnyExtendExpr(const SCEV *Op, const Type *Ty);
- const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops);
- const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS) {
+ const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
+ bool HasNUW = false, bool HasNSW = false);
+ const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS,
+ bool HasNUW = false, bool HasNSW = false) {
SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
- return getAddExpr(Ops);
+ return getAddExpr(Ops, HasNUW, HasNSW);
}
const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1,
- const SCEV *Op2) {
+ const SCEV *Op2,
+ bool HasNUW = false, bool HasNSW = false) {
SmallVector<const SCEV *, 3> Ops;
Ops.push_back(Op0);
Ops.push_back(Op1);
Ops.push_back(Op2);
- return getAddExpr(Ops);
+ return getAddExpr(Ops, HasNUW, HasNSW);
}
- const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops);
- const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS) {
+ const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
+ bool HasNUW = false, bool HasNSW = false);
+ const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS,
+ bool HasNUW = false, bool HasNSW = false) {
SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
- return getMulExpr(Ops);
+ return getMulExpr(Ops, HasNUW, HasNSW);
}
const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
- const Loop *L);
+ const Loop *L,
+ bool HasNUW = false, bool HasNSW = false);
const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L);
+ const Loop *L,
+ bool HasNUW = false, bool HasNSW = false);
const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L) {
+ const Loop *L,
+ bool HasNUW = false, bool HasNSW = false) {
SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
- return getAddRecExpr(NewOp, L);
+ return getAddRecExpr(NewOp, L, HasNUW, HasNSW);
}
const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
const SCEV *getUnknown(Value *V);
const SCEV *getCouldNotCompute();
+ /// getSizeOfExpr - Return an expression for sizeof on the given type.
+ ///
+ const SCEV *getSizeOfExpr(const Type *AllocTy);
+
+ /// getAlignOfExpr - Return an expression for alignof on the given type.
+ ///
+ const SCEV *getAlignOfExpr(const Type *AllocTy);
+
+ /// getOffsetOfExpr - Return an expression for offsetof on the given field.
+ ///
+ const SCEV *getOffsetOfExpr(const StructType *STy, unsigned FieldNo);
+
+ /// getOffsetOfExpr - Return an expression for offsetof on the given field.
+ ///
+ const SCEV *getOffsetOfExpr(const Type *CTy, Constant *FieldNo);
+
/// getNegativeSCEV - Return the SCEV object corresponding to -V.
///
const SCEV *getNegativeSCEV(const SCEV *V);
/// getMinusSCEV - Return LHS-RHS.
///
const SCEV *getMinusSCEV(const SCEV *LHS,
- const SCEV *RHS);
+ const SCEV *RHS);
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// widening.
const SCEV *getTruncateOrNoop(const SCEV *V, const Type *Ty);
- /// getIntegerSCEV - Given a SCEVable type, create a constant for the
- /// specified signed integer value and return a SCEV for the constant.
- const SCEV *getIntegerSCEV(int Val, const Type *Ty);
-
/// getUMaxFromMismatchedTypes - Promote the operands to the wider of
/// the types using zero-extension, and then perform a umax operation
/// with them.
const SCEV *getUMaxFromMismatchedTypes(const SCEV *LHS,
- const SCEV *RHS);
+ const SCEV *RHS);
/// getUMinFromMismatchedTypes - Promote the operands to the wider of
/// the types using zero-extension, and then perform a umin operation
const SCEV *getUMinFromMismatchedTypes(const SCEV *LHS,
const SCEV *RHS);
- /// getSCEVAtScope - Return a SCEV expression handle for the specified value
+ /// getSCEVAtScope - Return a SCEV expression for the specified value
/// at the specified scope in the program. The L value specifies a loop
/// nest to evaluate the expression at, where null is the top-level or a
/// specified loop is immediately inside of the loop.
/// getSCEVAtScope(getSCEV(V), L).
const SCEV *getSCEVAtScope(Value *V, const Loop *L);
- /// isLoopGuardedByCond - Test whether entry to the loop is protected by
- /// a conditional between LHS and RHS. This is used to help avoid max
+ /// isLoopEntryGuardedByCond - Test whether entry to the loop is protected
+ /// by a conditional between LHS and RHS. This is used to help avoid max
/// expressions in loop trip counts, and to eliminate casts.
- bool isLoopGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
- const SCEV *LHS, const SCEV *RHS);
+ bool isLoopEntryGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS);
/// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
/// protected by a conditional between LHS and RHS. This is used to
/// has an analyzable loop-invariant backedge-taken count.
bool hasLoopInvariantBackedgeTakenCount(const Loop *L);
- /// forgetLoopBackedgeTakenCount - This method should be called by the
- /// client when it has changed a loop in a way that may effect
- /// ScalarEvolution's ability to compute a trip count, or if the loop
- /// is deleted.
- void forgetLoopBackedgeTakenCount(const Loop *L);
+ /// forgetLoop - This method should be called by the client when it has
+ /// changed a loop in a way that may effect ScalarEvolution's ability to
+ /// compute a trip count, or if the loop is deleted.
+ void forgetLoop(const Loop *L);
+
+ /// forgetValue - This method should be called by the client when it has
+ /// changed a value in a way that may effect its value, or which may
+ /// disconnect it from a def-use chain linking it to a loop.
+ void forgetValue(Value *V);
/// GetMinTrailingZeros - Determine the minimum number of zero bits that S
/// is guaranteed to end in (at every loop iteration). It is, at the same
///
bool isKnownNonZero(const SCEV *S);
- /// isKnownNonZero - Test if the given expression is known to satisfy
+ /// isKnownPredicate - Test if the given expression is known to satisfy
/// the condition described by Pred, LHS, and RHS.
///
bool isKnownPredicate(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS);
+ /// SimplifyICmpOperands - Simplify LHS and RHS in a comparison with
+ /// predicate Pred. Return true iff any changes were made. If the
+ /// operands are provably equal or inequal, LHS and RHS are set to
+ /// the same value and Pred is set to either ICMP_EQ or ICMP_NE.
+ ///
+ bool SimplifyICmpOperands(ICmpInst::Predicate &Pred,
+ const SCEV *&LHS,
+ const SCEV *&RHS);
+
virtual bool runOnFunction(Function &F);
virtual void releaseMemory();
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
- void print(raw_ostream &OS, const Module* = 0) const;
- virtual void print(std::ostream &OS, const Module* = 0) const;
- void print(std::ostream *OS, const Module* M = 0) const {
- if (OS) print(*OS, M);
- }
+ virtual void print(raw_ostream &OS, const Module* = 0) const;
private:
FoldingSet<SCEV> UniqueSCEVs;
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