// There are several aspects to this library. First is the representation of
// scalar expressions, which are represented as subclasses of the SCEV class.
// These classes are used to represent certain types of subexpressions that we
-// can handle. These classes are reference counted, managed by the const SCEV *
-// class. We only create one SCEV of a particular shape, so pointer-comparisons
-// for equality are legal.
+// can handle. We only create one SCEV of a particular shape, so
+// pointer-comparisons for equality are legal.
//
// One important aspect of the SCEV objects is that they are never cyclic, even
// if there is a cycle in the dataflow for an expression (ie, a PHI node). If
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalVariable.h"
+#include "llvm/GlobalAlias.h"
#include "llvm/Instructions.h"
#include "llvm/LLVMContext.h"
+#include "llvm/Operator.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Compiler.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
errs() << '\n';
}
-void SCEV::print(std::ostream &o) const {
- raw_os_ostream OS(o);
- print(OS);
-}
-
bool SCEV::isZero() const {
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
return SC->getValue()->isZero();
SCEV(FoldingSetNodeID(), scCouldNotCompute) {}
bool SCEVCouldNotCompute::isLoopInvariant(const Loop *L) const {
- LLVM_UNREACHABLE("Attempt to use a SCEVCouldNotCompute object!");
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return false;
}
const Type *SCEVCouldNotCompute::getType() const {
- LLVM_UNREACHABLE("Attempt to use a SCEVCouldNotCompute object!");
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return 0;
}
bool SCEVCouldNotCompute::hasComputableLoopEvolution(const Loop *L) const {
- LLVM_UNREACHABLE("Attempt to use a SCEVCouldNotCompute object!");
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return false;
}
-const SCEV *
-SCEVCouldNotCompute::replaceSymbolicValuesWithConcrete(
- const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- return this;
+bool SCEVCouldNotCompute::hasOperand(const SCEV *) const {
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
+ return false;
}
void SCEVCouldNotCompute::print(raw_ostream &OS) const {
}
const SCEV *ScalarEvolution::getConstant(const APInt& Val) {
- return getConstant(ConstantInt::get(Val));
+ return getConstant(ConstantInt::get(getContext(), Val));
}
const SCEV *
ScalarEvolution::getConstant(const Type *Ty, uint64_t V, bool isSigned) {
- return getConstant(ConstantInt::get(cast<IntegerType>(Ty), V, isSigned));
+ return getConstant(
+ ConstantInt::get(cast<IntegerType>(Ty), V, isSigned));
}
const Type *SCEVConstant::getType() const { return V->getType(); }
return Op->dominates(BB, DT);
}
+bool SCEVCastExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ return Op->properlyDominates(BB, DT);
+}
+
SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeID &ID,
const SCEV *op, const Type *ty)
: SCEVCastExpr(ID, scTruncate, op, ty) {
OS << ")";
}
-const SCEV *
-SCEVCommutativeExpr::replaceSymbolicValuesWithConcrete(
- const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
+bool SCEVNAryExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- const SCEV *H =
- getOperand(i)->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H != getOperand(i)) {
- SmallVector<const SCEV *, 8> NewOps;
- NewOps.reserve(getNumOperands());
- for (unsigned j = 0; j != i; ++j)
- NewOps.push_back(getOperand(j));
- NewOps.push_back(H);
- for (++i; i != e; ++i)
- NewOps.push_back(getOperand(i)->
- replaceSymbolicValuesWithConcrete(Sym, Conc, SE));
-
- if (isa<SCEVAddExpr>(this))
- return SE.getAddExpr(NewOps);
- else if (isa<SCEVMulExpr>(this))
- return SE.getMulExpr(NewOps);
- else if (isa<SCEVSMaxExpr>(this))
- return SE.getSMaxExpr(NewOps);
- else if (isa<SCEVUMaxExpr>(this))
- return SE.getUMaxExpr(NewOps);
- else
- LLVM_UNREACHABLE("Unknown commutative expr!");
- }
+ if (!getOperand(i)->dominates(BB, DT))
+ return false;
}
- return this;
+ return true;
}
-bool SCEVNAryExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
+bool SCEVNAryExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- if (!getOperand(i)->dominates(BB, DT))
+ if (!getOperand(i)->properlyDominates(BB, DT))
return false;
}
return true;
return LHS->dominates(BB, DT) && RHS->dominates(BB, DT);
}
+bool SCEVUDivExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ return LHS->properlyDominates(BB, DT) && RHS->properlyDominates(BB, DT);
+}
+
void SCEVUDivExpr::print(raw_ostream &OS) const {
OS << "(" << *LHS << " /u " << *RHS << ")";
}
return RHS->getType();
}
-const SCEV *
-SCEVAddRecExpr::replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- const SCEV *H =
- getOperand(i)->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H != getOperand(i)) {
- SmallVector<const SCEV *, 8> NewOps;
- NewOps.reserve(getNumOperands());
- for (unsigned j = 0; j != i; ++j)
- NewOps.push_back(getOperand(j));
- NewOps.push_back(H);
- for (++i; i != e; ++i)
- NewOps.push_back(getOperand(i)->
- replaceSymbolicValuesWithConcrete(Sym, Conc, SE));
-
- return SE.getAddRecExpr(NewOps, L);
- }
- }
- return this;
-}
-
-
bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
// Add recurrences are never invariant in the function-body (null loop).
if (!QueryLoop)
return false;
// This recurrence is variant w.r.t. QueryLoop if QueryLoop contains L.
- if (QueryLoop->contains(L->getHeader()))
+ if (QueryLoop->contains(L))
return false;
// This recurrence is variant w.r.t. QueryLoop if any of its operands
OS << "}<" << L->getHeader()->getName() + ">";
}
+void SCEVFieldOffsetExpr::print(raw_ostream &OS) const {
+ // LLVM struct fields don't have names, so just print the field number.
+ OS << "offsetof(" << *STy << ", " << FieldNo << ")";
+}
+
+void SCEVAllocSizeExpr::print(raw_ostream &OS) const {
+ OS << "sizeof(" << *AllocTy << ")";
+}
+
bool SCEVUnknown::isLoopInvariant(const Loop *L) const {
// All non-instruction values are loop invariant. All instructions are loop
// invariant if they are not contained in the specified loop.
// Instructions are never considered invariant in the function body
// (null loop) because they are defined within the "loop".
if (Instruction *I = dyn_cast<Instruction>(V))
- return L && !L->contains(I->getParent());
+ return L && !L->contains(I);
return true;
}
return true;
}
+bool SCEVUnknown::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ if (Instruction *I = dyn_cast<Instruction>(getValue()))
+ return DT->properlyDominates(I->getParent(), BB);
+ return true;
+}
+
const Type *SCEVUnknown::getType() const {
return V->getType();
}
// SCEV Utilities
//===----------------------------------------------------------------------===//
+static bool CompareTypes(const Type *A, const Type *B) {
+ if (A->getTypeID() != B->getTypeID())
+ return A->getTypeID() < B->getTypeID();
+ if (const IntegerType *AI = dyn_cast<IntegerType>(A)) {
+ const IntegerType *BI = cast<IntegerType>(B);
+ return AI->getBitWidth() < BI->getBitWidth();
+ }
+ if (const PointerType *AI = dyn_cast<PointerType>(A)) {
+ const PointerType *BI = cast<PointerType>(B);
+ return CompareTypes(AI->getElementType(), BI->getElementType());
+ }
+ if (const ArrayType *AI = dyn_cast<ArrayType>(A)) {
+ const ArrayType *BI = cast<ArrayType>(B);
+ if (AI->getNumElements() != BI->getNumElements())
+ return AI->getNumElements() < BI->getNumElements();
+ return CompareTypes(AI->getElementType(), BI->getElementType());
+ }
+ if (const VectorType *AI = dyn_cast<VectorType>(A)) {
+ const VectorType *BI = cast<VectorType>(B);
+ if (AI->getNumElements() != BI->getNumElements())
+ return AI->getNumElements() < BI->getNumElements();
+ return CompareTypes(AI->getElementType(), BI->getElementType());
+ }
+ if (const StructType *AI = dyn_cast<StructType>(A)) {
+ const StructType *BI = cast<StructType>(B);
+ if (AI->getNumElements() != BI->getNumElements())
+ return AI->getNumElements() < BI->getNumElements();
+ for (unsigned i = 0, e = AI->getNumElements(); i != e; ++i)
+ if (CompareTypes(AI->getElementType(i), BI->getElementType(i)) ||
+ CompareTypes(BI->getElementType(i), AI->getElementType(i)))
+ return CompareTypes(AI->getElementType(i), BI->getElementType(i));
+ }
+ return false;
+}
+
namespace {
/// SCEVComplexityCompare - Return true if the complexity of the LHS is less
/// than the complexity of the RHS. This comparator is used to canonicalize
/// expressions.
- class VISIBILITY_HIDDEN SCEVComplexityCompare {
+ class SCEVComplexityCompare {
LoopInfo *LI;
public:
explicit SCEVComplexityCompare(LoopInfo *li) : LI(li) {}
bool operator()(const SCEV *LHS, const SCEV *RHS) const {
+ // Fast-path: SCEVs are uniqued so we can do a quick equality check.
+ if (LHS == RHS)
+ return false;
+
// Primarily, sort the SCEVs by their getSCEVType().
if (LHS->getSCEVType() != RHS->getSCEVType())
return LHS->getSCEVType() < RHS->getSCEVType();
return operator()(LC->getOperand(), RC->getOperand());
}
- LLVM_UNREACHABLE("Unknown SCEV kind!");
+ // Compare offsetof expressions.
+ if (const SCEVFieldOffsetExpr *LA = dyn_cast<SCEVFieldOffsetExpr>(LHS)) {
+ const SCEVFieldOffsetExpr *RA = cast<SCEVFieldOffsetExpr>(RHS);
+ if (CompareTypes(LA->getStructType(), RA->getStructType()) ||
+ CompareTypes(RA->getStructType(), LA->getStructType()))
+ return CompareTypes(LA->getStructType(), RA->getStructType());
+ return LA->getFieldNo() < RA->getFieldNo();
+ }
+
+ // Compare sizeof expressions by the allocation type.
+ if (const SCEVAllocSizeExpr *LA = dyn_cast<SCEVAllocSizeExpr>(LHS)) {
+ const SCEVAllocSizeExpr *RA = cast<SCEVAllocSizeExpr>(RHS);
+ return CompareTypes(LA->getAllocType(), RA->getAllocType());
+ }
+
+ llvm_unreachable("Unknown SCEV kind!");
return false;
}
};
/// BinomialCoefficient - Compute BC(It, K). The result has width W.
/// Assume, K > 0.
static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K,
- ScalarEvolution &SE,
- const Type* ResultTy) {
+ ScalarEvolution &SE,
+ const Type* ResultTy) {
// Handle the simplest case efficiently.
if (K == 1)
return SE.getTruncateOrZeroExtend(It, ResultTy);
MultiplyFactor = MultiplyFactor.trunc(W);
// Calculate the product, at width T+W
- const IntegerType *CalculationTy = IntegerType::get(CalculationBits);
+ const IntegerType *CalculationTy = IntegerType::get(SE.getContext(),
+ CalculationBits);
const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy);
for (unsigned i = 1; i != K; ++i) {
const SCEV *S = SE.getMinusSCEV(It, SE.getIntegerSCEV(i, It->getType()));
/// where BC(It, k) stands for binomial coefficient.
///
const SCEV *SCEVAddRecExpr::evaluateAtIteration(const SCEV *It,
- ScalarEvolution &SE) const {
+ ScalarEvolution &SE) const {
const SCEV *Result = getStart();
for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
// The computation is correct in the face of overflow provided that the
unsigned BitWidth = getTypeSizeInBits(AR->getType());
const Loop *L = AR->getLoop();
+ // If we have special knowledge that this addrec won't overflow,
+ // we don't need to do any further analysis.
+ if (AR->hasNoUnsignedWrap())
+ return getAddRecExpr(getZeroExtendExpr(Start, Ty),
+ getZeroExtendExpr(Step, Ty),
+ L);
+
// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
// simply not analyzable, and it covers the case where this code is
const SCEV *RecastedMaxBECount =
getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
if (MaxBECount == RecastedMaxBECount) {
- const Type *WideTy = IntegerType::get(BitWidth * 2);
+ const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
// Check whether Start+Step*MaxBECount has no unsigned overflow.
const SCEV *ZMul =
getMulExpr(CastedMaxBECount,
unsigned BitWidth = getTypeSizeInBits(AR->getType());
const Loop *L = AR->getLoop();
+ // If we have special knowledge that this addrec won't overflow,
+ // we don't need to do any further analysis.
+ if (AR->hasNoSignedWrap())
+ return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ getSignExtendExpr(Step, Ty),
+ L);
+
// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
// simply not analyzable, and it covers the case where this code is
const SCEV *RecastedMaxBECount =
getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
if (MaxBECount == RecastedMaxBECount) {
- const Type *WideTy = IntegerType::get(BitWidth * 2);
+ const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
// Check whether Start+Step*MaxBECount has no signed overflow.
const SCEV *SMul =
getMulExpr(CastedMaxBECount,
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
L);
+
+ // Similar to above, only this time treat the step value as unsigned.
+ // This covers loops that count up with an unsigned step.
+ const SCEV *UMul =
+ getMulExpr(CastedMaxBECount,
+ getTruncateOrZeroExtend(Step, Start->getType()));
+ Add = getAddExpr(Start, UMul);
+ OperandExtendedAdd =
+ getAddExpr(getSignExtendExpr(Start, WideTy),
+ getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+ getZeroExtendExpr(Step, WideTy)));
+ if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ getZeroExtendExpr(Step, Ty),
+ L);
}
// If the backedge is guarded by a comparison with the pre-inc value
/// unspecified bits out to the given type.
///
const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op,
- const Type *Ty) {
+ const Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
"This is not an extending conversion!");
assert(isSCEVable(Ty) &&
/// getAddExpr - Get a canonical add expression, or something simpler if
/// possible.
-const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops) {
+const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
+ bool HasNUW, bool HasNSW) {
assert(!Ops.empty() && "Cannot get empty add!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
return Mul;
Ops.erase(Ops.begin()+i, Ops.begin()+i+2);
Ops.push_back(Mul);
- return getAddExpr(Ops);
+ return getAddExpr(Ops, HasNUW, HasNSW);
}
// Check for truncates. If all the operands are truncated from the same
}
if (Ok) {
// Evaluate the expression in the larger type.
- const SCEV *Fold = getAddExpr(LargeOps);
+ const SCEV *Fold = getAddExpr(LargeOps, HasNUW, HasNSW);
// If it folds to something simple, use it. Otherwise, don't.
if (isa<SCEVConstant>(Fold) || isa<SCEVUnknown>(Fold))
return getTruncateExpr(Fold, DstType);
LIOps.push_back(AddRec->getStart());
SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(),
- AddRec->op_end());
+ AddRec->op_end());
AddRecOps[0] = getAddExpr(LIOps);
+ // It's tempting to propagate NUW/NSW flags here, but nuw/nsw addition
+ // is not associative so this isn't necessarily safe.
const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRec->getLoop());
+
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
ID.AddPointer(Ops[i]);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVAddExpr>();
+ SCEVAddExpr *S = SCEVAllocator.Allocate<SCEVAddExpr>();
new (S) SCEVAddExpr(ID, Ops);
UniqueSCEVs.InsertNode(S, IP);
+ if (HasNUW) S->setHasNoUnsignedWrap(true);
+ if (HasNSW) S->setHasNoSignedWrap(true);
return S;
}
/// getMulExpr - Get a canonical multiply expression, or something simpler if
/// possible.
-const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops) {
+const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
+ bool HasNUW, bool HasNSW) {
assert(!Ops.empty() && "Cannot get empty mul!");
#ifndef NDEBUG
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
++Idx;
while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
// We found two constants, fold them together!
- ConstantInt *Fold = ConstantInt::get(LHSC->getValue()->getValue() *
+ ConstantInt *Fold = ConstantInt::get(getContext(),
+ LHSC->getValue()->getValue() *
RHSC->getValue()->getValue());
Ops[0] = getConstant(Fold);
Ops.erase(Ops.begin()+1); // Erase the folded element
}
}
+ // It's tempting to propagate the NSW flag here, but nsw multiplication
+ // is not associative so this isn't necessarily safe.
const SCEV *NewRec = getAddRecExpr(NewOps, AddRec->getLoop());
// If all of the other operands were loop invariant, we are done.
ID.AddPointer(Ops[i]);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVMulExpr>();
+ SCEVMulExpr *S = SCEVAllocator.Allocate<SCEVMulExpr>();
new (S) SCEVMulExpr(ID, Ops);
UniqueSCEVs.InsertNode(S, IP);
+ if (HasNUW) S->setHasNoUnsignedWrap(true);
+ if (HasNSW) S->setHasNoSignedWrap(true);
return S;
}
-/// getUDivExpr - Get a canonical multiply expression, or something simpler if
-/// possible.
+/// getUDivExpr - Get a canonical unsigned division expression, or something
+/// simpler if possible.
const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS,
const SCEV *RHS) {
assert(getEffectiveSCEVType(LHS->getType()) ==
if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
if (RHSC->getValue()->equalsInt(1))
- return LHS; // X udiv 1 --> x
+ return LHS; // X udiv 1 --> x
if (RHSC->isZero())
return getIntegerSCEV(0, LHS->getType()); // value is undefined
if (!RHSC->getValue()->getValue().isPowerOf2())
++MaxShiftAmt;
const IntegerType *ExtTy =
- IntegerType::get(getTypeSizeInBits(Ty) + MaxShiftAmt);
+ IntegerType::get(getContext(), getTypeSizeInBits(Ty) + MaxShiftAmt);
// {X,+,N}/C --> {X/C,+,N/C} if safe and N/C can be folded.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS))
if (const SCEVConstant *Step =
/// getAddRecExpr - Get an add recurrence expression for the specified loop.
/// Simplify the expression as much as possible.
const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start,
- const SCEV *Step, const Loop *L) {
+ const SCEV *Step, const Loop *L,
+ bool HasNUW, bool HasNSW) {
SmallVector<const SCEV *, 4> Operands;
Operands.push_back(Start);
if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
}
Operands.push_back(Step);
- return getAddRecExpr(Operands, L);
+ return getAddRecExpr(Operands, L, HasNUW, HasNSW);
}
/// getAddRecExpr - Get an add recurrence expression for the specified loop.
/// Simplify the expression as much as possible.
const SCEV *
ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L) {
+ const Loop *L,
+ bool HasNUW, bool HasNSW) {
if (Operands.size() == 1) return Operands[0];
#ifndef NDEBUG
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
if (Operands.back()->isZero()) {
Operands.pop_back();
- return getAddRecExpr(Operands, L); // {X,+,0} --> X
+ return getAddRecExpr(Operands, L, HasNUW, HasNSW); // {X,+,0} --> X
}
// Canonicalize nested AddRecs in by nesting them in order of loop depth.
if (const SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) {
- const Loop* NestedLoop = NestedAR->getLoop();
+ const Loop *NestedLoop = NestedAR->getLoop();
if (L->getLoopDepth() < NestedLoop->getLoopDepth()) {
SmallVector<const SCEV *, 4> NestedOperands(NestedAR->op_begin(),
- NestedAR->op_end());
+ NestedAR->op_end());
Operands[0] = NestedAR->getStart();
// AddRecs require their operands be loop-invariant with respect to their
// loops. Don't perform this transformation if it would break this
}
if (AllInvariant)
// Ok, both add recurrences are valid after the transformation.
- return getAddRecExpr(NestedOperands, NestedLoop);
+ return getAddRecExpr(NestedOperands, NestedLoop, HasNUW, HasNSW);
}
// Reset Operands to its original state.
Operands[0] = NestedAR;
ID.AddPointer(L);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVAddRecExpr>();
+ SCEVAddRecExpr *S = SCEVAllocator.Allocate<SCEVAddRecExpr>();
new (S) SCEVAddRecExpr(ID, Operands, L);
UniqueSCEVs.InsertNode(S, IP);
+ if (HasNUW) S->setHasNoUnsignedWrap(true);
+ if (HasNSW) S->setHasNoSignedWrap(true);
return S;
}
assert(Idx < Ops.size());
while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
// We found two constants, fold them together!
- ConstantInt *Fold = ConstantInt::get(
+ ConstantInt *Fold = ConstantInt::get(getContext(),
APIntOps::smax(LHSC->getValue()->getValue(),
RHSC->getValue()->getValue()));
Ops[0] = getConstant(Fold);
assert(Idx < Ops.size());
while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
// We found two constants, fold them together!
- ConstantInt *Fold = ConstantInt::get(
+ ConstantInt *Fold = ConstantInt::get(getContext(),
APIntOps::umax(LHSC->getValue()->getValue(),
RHSC->getValue()->getValue()));
Ops[0] = getConstant(Fold);
return getNotSCEV(getUMaxExpr(getNotSCEV(LHS), getNotSCEV(RHS)));
}
+const SCEV *ScalarEvolution::getFieldOffsetExpr(const StructType *STy,
+ unsigned FieldNo) {
+ // If we have TargetData we can determine the constant offset.
+ if (TD) {
+ const Type *IntPtrTy = TD->getIntPtrType(getContext());
+ const StructLayout &SL = *TD->getStructLayout(STy);
+ uint64_t Offset = SL.getElementOffset(FieldNo);
+ return getIntegerSCEV(Offset, IntPtrTy);
+ }
+
+ // Field 0 is always at offset 0.
+ if (FieldNo == 0) {
+ const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
+ return getIntegerSCEV(0, Ty);
+ }
+
+ // Okay, it looks like we really DO need an offsetof expr. Check to see if we
+ // already have one, otherwise create a new one.
+ FoldingSetNodeID ID;
+ ID.AddInteger(scFieldOffset);
+ ID.AddPointer(STy);
+ ID.AddInteger(FieldNo);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVFieldOffsetExpr>();
+ const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
+ new (S) SCEVFieldOffsetExpr(ID, Ty, STy, FieldNo);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
+}
+
+const SCEV *ScalarEvolution::getAllocSizeExpr(const Type *AllocTy) {
+ // If we have TargetData we can determine the constant size.
+ if (TD && AllocTy->isSized()) {
+ const Type *IntPtrTy = TD->getIntPtrType(getContext());
+ return getIntegerSCEV(TD->getTypeAllocSize(AllocTy), IntPtrTy);
+ }
+
+ // Expand an array size into the element size times the number
+ // of elements.
+ if (const ArrayType *ATy = dyn_cast<ArrayType>(AllocTy)) {
+ const SCEV *E = getAllocSizeExpr(ATy->getElementType());
+ return getMulExpr(
+ E, getConstant(ConstantInt::get(cast<IntegerType>(E->getType()),
+ ATy->getNumElements())));
+ }
+
+ // Expand a vector size into the element size times the number
+ // of elements.
+ if (const VectorType *VTy = dyn_cast<VectorType>(AllocTy)) {
+ const SCEV *E = getAllocSizeExpr(VTy->getElementType());
+ return getMulExpr(
+ E, getConstant(ConstantInt::get(cast<IntegerType>(E->getType()),
+ VTy->getNumElements())));
+ }
+
+ // Okay, it looks like we really DO need a sizeof expr. Check to see if we
+ // already have one, otherwise create a new one.
+ FoldingSetNodeID ID;
+ ID.AddInteger(scAllocSize);
+ ID.AddPointer(AllocTy);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVAllocSizeExpr>();
+ const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
+ new (S) SCEVAllocSizeExpr(ID, Ty, AllocTy);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
+}
+
const SCEV *ScalarEvolution::getUnknown(Value *V) {
// Don't attempt to do anything other than create a SCEVUnknown object
// here. createSCEV only calls getUnknown after checking for all other
/// can optionally include pointer types if the ScalarEvolution class
/// has access to target-specific information.
bool ScalarEvolution::isSCEVable(const Type *Ty) const {
- // Integers are always SCEVable.
- if (Ty->isInteger())
- return true;
-
- // Pointers are SCEVable if TargetData information is available
- // to provide pointer size information.
- if (isa<PointerType>(Ty))
- return TD != NULL;
-
- // Otherwise it's not SCEVable.
- return false;
+ // Integers and pointers are always SCEVable.
+ return Ty->isInteger() || isa<PointerType>(Ty);
}
/// getTypeSizeInBits - Return the size in bits of the specified type,
if (TD)
return TD->getTypeSizeInBits(Ty);
- // Otherwise, we support only integer types.
- assert(Ty->isInteger() && "isSCEVable permitted a non-SCEVable type!");
- return Ty->getPrimitiveSizeInBits();
+ // Integer types have fixed sizes.
+ if (Ty->isInteger())
+ return Ty->getPrimitiveSizeInBits();
+
+ // The only other support type is pointer. Without TargetData, conservatively
+ // assume pointers are 64-bit.
+ assert(isa<PointerType>(Ty) && "isSCEVable permitted a non-SCEVable type!");
+ return 64;
}
/// getEffectiveSCEVType - Return a type with the same bitwidth as
if (Ty->isInteger())
return Ty;
+ // The only other support type is pointer.
assert(isa<PointerType>(Ty) && "Unexpected non-pointer non-integer type!");
- return TD->getIntPtrType();
+ if (TD) return TD->getIntPtrType(getContext());
+
+ // Without TargetData, conservatively assume pointers are 64-bit.
+ return Type::getInt64Ty(getContext());
}
const SCEV *ScalarEvolution::getCouldNotCompute() {
const SCEV *ScalarEvolution::getNegativeSCEV(const SCEV *V) {
if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
return getConstant(
- cast<ConstantInt>(Context->getConstantExprNeg(VC->getValue())));
+ cast<ConstantInt>(ConstantExpr::getNeg(VC->getValue())));
const Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
return getMulExpr(V,
- getConstant(cast<ConstantInt>(Context->getAllOnesValue(Ty))));
+ getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))));
}
/// getNotSCEV - Return a SCEV corresponding to ~V = -1-V
const SCEV *ScalarEvolution::getNotSCEV(const SCEV *V) {
if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
return getConstant(
- cast<ConstantInt>(Context->getConstantExprNot(VC->getValue())));
+ cast<ConstantInt>(ConstantExpr::getNot(VC->getValue())));
const Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
const SCEV *AllOnes =
- getConstant(cast<ConstantInt>(Context->getAllOnesValue(Ty)));
+ getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty)));
return getMinusSCEV(AllOnes, V);
}
ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V,
const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
- (Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
+ assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+ (Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate or zero extend with non-integer arguments!");
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
return V; // No conversion
ScalarEvolution::getTruncateOrSignExtend(const SCEV *V,
const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
- (Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
+ assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+ (Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate or zero extend with non-integer arguments!");
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
return V; // No conversion
const SCEV *
ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
- (Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
+ assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+ (Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot noop or zero extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrZeroExtend cannot truncate!");
const SCEV *
ScalarEvolution::getNoopOrSignExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
- (Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
+ assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+ (Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot noop or sign extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrSignExtend cannot truncate!");
const SCEV *
ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
- (Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
+ assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+ (Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot noop or any extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrAnyExtend cannot truncate!");
const SCEV *
ScalarEvolution::getTruncateOrNoop(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
- (Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
+ assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+ (Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate or noop with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&
"getTruncateOrNoop cannot extend!");
return getUMinExpr(PromotedLHS, PromotedRHS);
}
-/// 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.
+/// PushDefUseChildren - Push users of the given Instruction
+/// onto the given Worklist.
+static void
+PushDefUseChildren(Instruction *I,
+ SmallVectorImpl<Instruction *> &Worklist) {
+ // Push the def-use children onto the Worklist stack.
+ for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
+ UI != UE; ++UI)
+ Worklist.push_back(cast<Instruction>(UI));
+}
+
+/// 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
-ScalarEvolution::ReplaceSymbolicValueWithConcrete(Instruction *I,
- const SCEV *SymName,
- const SCEV *NewVal) {
- std::map<SCEVCallbackVH, const SCEV *>::iterator SI =
- Scalars.find(SCEVCallbackVH(I, this));
- if (SI == Scalars.end()) return;
+ScalarEvolution::ForgetSymbolicName(Instruction *I, const SCEV *SymName) {
+ SmallVector<Instruction *, 16> Worklist;
+ PushDefUseChildren(I, Worklist);
- const SCEV *NV =
- SI->second->replaceSymbolicValuesWithConcrete(SymName, NewVal, *this);
- if (NV == SI->second) return; // No change.
+ SmallPtrSet<Instruction *, 8> Visited;
+ Visited.insert(I);
+ while (!Worklist.empty()) {
+ Instruction *I = Worklist.pop_back_val();
+ if (!Visited.insert(I)) continue;
- SI->second = NV; // Update the scalars map!
+ std::map<SCEVCallbackVH, const SCEV *>::iterator It =
+ Scalars.find(static_cast<Value *>(I));
+ if (It != Scalars.end()) {
+ // Short-circuit the def-use traversal if the symbolic name
+ // ceases to appear in expressions.
+ if (!It->second->hasOperand(SymName))
+ continue;
+
+ // SCEVUnknown for a PHI either means that it has an unrecognized
+ // structure, or it's a PHI that's in the progress of being computed
+ // by createNodeForPHI. In the former case, additional loop trip
+ // count information isn't going to change anything. In the later
+ // case, createNodeForPHI will perform the necessary updates on its
+ // own when it gets to that point.
+ if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second)) {
+ ValuesAtScopes.erase(It->second);
+ Scalars.erase(It);
+ }
+ }
- // Any instruction values that use this instruction might also need to be
- // updated!
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI)
- ReplaceSymbolicValueWithConcrete(cast<Instruction>(*UI), SymName, NewVal);
+ PushDefUseChildren(I, Worklist);
+ }
}
/// createNodeForPHI - PHI nodes have two cases. Either the PHI node exists in
// Using this symbolic name for the PHI, analyze the value coming around
// the back-edge.
- const SCEV *BEValue = getSCEV(PN->getIncomingValue(BackEdge));
+ Value *BEValueV = PN->getIncomingValue(BackEdge);
+ const SCEV *BEValue = getSCEV(BEValueV);
// NOTE: If BEValue is loop invariant, we know that the PHI node just
// has a special value for the first iteration of the loop.
cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) {
const SCEV *StartVal =
getSCEV(PN->getIncomingValue(IncomingEdge));
- const SCEV *PHISCEV =
- getAddRecExpr(StartVal, Accum, L);
+ const SCEVAddRecExpr *PHISCEV =
+ cast<SCEVAddRecExpr>(getAddRecExpr(StartVal, Accum, L));
+
+ // If the increment doesn't overflow, then neither the addrec nor the
+ // post-increment will overflow.
+ if (const AddOperator *OBO = dyn_cast<AddOperator>(BEValueV))
+ if (OBO->getOperand(0) == PN &&
+ getSCEV(OBO->getOperand(1)) ==
+ PHISCEV->getStepRecurrence(*this)) {
+ const SCEVAddRecExpr *PostInc = PHISCEV->getPostIncExpr(*this);
+ if (OBO->hasNoUnsignedWrap()) {
+ const_cast<SCEVAddRecExpr *>(PHISCEV)
+ ->setHasNoUnsignedWrap(true);
+ const_cast<SCEVAddRecExpr *>(PostInc)
+ ->setHasNoUnsignedWrap(true);
+ }
+ if (OBO->hasNoSignedWrap()) {
+ const_cast<SCEVAddRecExpr *>(PHISCEV)
+ ->setHasNoSignedWrap(true);
+ const_cast<SCEVAddRecExpr *>(PostInc)
+ ->setHasNoSignedWrap(true);
+ }
+ }
// Okay, for the entire analysis of this edge we assumed the PHI
- // to be symbolic. We now need to go back and update all of the
- // entries for the scalars that use the PHI (except for the PHI
- // itself) to use the new analyzed value instead of the "symbolic"
- // value.
- ReplaceSymbolicValueWithConcrete(PN, SymbolicName, PHISCEV);
+ // to be symbolic. We now need to go back and purge all of the
+ // entries for the scalars that use the symbolic expression.
+ ForgetSymbolicName(PN, SymbolicName);
+ Scalars[SCEVCallbackVH(PN, this)] = PHISCEV;
return PHISCEV;
}
}
getAddRecExpr(StartVal, AddRec->getOperand(1), L);
// Okay, for the entire analysis of this edge we assumed the PHI
- // to be symbolic. We now need to go back and update all of the
- // entries for the scalars that use the PHI (except for the PHI
- // itself) to use the new analyzed value instead of the "symbolic"
- // value.
- ReplaceSymbolicValueWithConcrete(PN, SymbolicName, PHISCEV);
+ // to be symbolic. We now need to go back and purge all of the
+ // entries for the scalars that use the symbolic expression.
+ ForgetSymbolicName(PN, SymbolicName);
+ Scalars[SCEVCallbackVH(PN, this)] = PHISCEV;
return PHISCEV;
}
}
return SymbolicName;
}
+ // It's tempting to recognize PHIs with a unique incoming value, however
+ // this leads passes like indvars to break LCSSA form. Fortunately, such
+ // PHIs are rare, as instcombine zaps them.
+
// If it's not a loop phi, we can't handle it yet.
return getUnknown(PN);
}
/// createNodeForGEP - Expand GEP instructions into add and multiply
/// operations. This allows them to be analyzed by regular SCEV code.
///
-const SCEV *ScalarEvolution::createNodeForGEP(User *GEP) {
+const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) {
- const Type *IntPtrTy = TD->getIntPtrType();
+ bool InBounds = GEP->isInBounds();
+ const Type *IntPtrTy = getEffectiveSCEVType(GEP->getType());
Value *Base = GEP->getOperand(0);
// Don't attempt to analyze GEPs over unsized objects.
if (!cast<PointerType>(Base->getType())->getElementType()->isSized())
// Compute the (potentially symbolic) offset in bytes for this index.
if (const StructType *STy = dyn_cast<StructType>(*GTI++)) {
// For a struct, add the member offset.
- const StructLayout &SL = *TD->getStructLayout(STy);
unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
- uint64_t Offset = SL.getElementOffset(FieldNo);
- TotalOffset = getAddExpr(TotalOffset, getIntegerSCEV(Offset, IntPtrTy));
+ TotalOffset = getAddExpr(TotalOffset,
+ getFieldOffsetExpr(STy, FieldNo),
+ /*HasNUW=*/false, /*HasNSW=*/InBounds);
} else {
// For an array, add the element offset, explicitly scaled.
const SCEV *LocalOffset = getSCEV(Index);
if (!isa<PointerType>(LocalOffset->getType()))
// Getelementptr indicies are signed.
LocalOffset = getTruncateOrSignExtend(LocalOffset, IntPtrTy);
- LocalOffset =
- getMulExpr(LocalOffset,
- getIntegerSCEV(TD->getTypeAllocSize(*GTI), IntPtrTy));
- TotalOffset = getAddExpr(TotalOffset, LocalOffset);
+ // Lower "inbounds" GEPs to NSW arithmetic.
+ LocalOffset = getMulExpr(LocalOffset, getAllocSizeExpr(*GTI),
+ /*HasNUW=*/false, /*HasNSW=*/InBounds);
+ TotalOffset = getAddExpr(TotalOffset, LocalOffset,
+ /*HasNUW=*/false, /*HasNSW=*/InBounds);
}
}
- return getAddExpr(getSCEV(Base), TotalOffset);
+ return getAddExpr(getSCEV(Base), TotalOffset,
+ /*HasNUW=*/false, /*HasNSW=*/InBounds);
}
/// GetMinTrailingZeros - Determine the minimum number of zero bits that S is
MaxBECount = getNoopOrZeroExtend(MaxBECount, Ty);
const SCEV *Start = AddRec->getStart();
+ const SCEV *Step = AddRec->getStepRecurrence(*this);
const SCEV *End = AddRec->evaluateAtIteration(MaxBECount, *this);
// Check for overflow.
- if (!isKnownPredicate(ICmpInst::ICMP_ULE, Start, End))
+ // TODO: This is very conservative.
+ if (!(Step->isOne() &&
+ isKnownPredicate(ICmpInst::ICMP_ULT, Start, End)) &&
+ !(Step->isAllOnesValue() &&
+ isKnownPredicate(ICmpInst::ICMP_UGT, Start, End)))
return FullSet;
ConstantRange StartRange = getUnsignedRange(Start);
APInt Max = APIntOps::umax(StartRange.getUnsignedMax(),
EndRange.getUnsignedMax());
if (Min.isMinValue() && Max.isMaxValue())
- return ConstantRange(Min.getBitWidth(), /*isFullSet=*/true);
+ return FullSet;
return ConstantRange(Min, Max+1);
}
}
APInt Mask = APInt::getAllOnesValue(BitWidth);
APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD);
- return ConstantRange(Ones, ~Zeros);
+ if (Ones == ~Zeros + 1)
+ return FullSet;
+ return ConstantRange(Ones, ~Zeros + 1);
}
return FullSet;
const SCEV *End = AddRec->evaluateAtIteration(MaxBECount, *this);
// Check for overflow.
- if (!(isKnownPositive(Step) &&
+ // TODO: This is very conservative.
+ if (!(Step->isOne() &&
isKnownPredicate(ICmpInst::ICMP_SLT, Start, End)) &&
- !(isKnownNegative(Step) &&
+ !(Step->isAllOnesValue() &&
isKnownPredicate(ICmpInst::ICMP_SGT, Start, End)))
return FullSet;
APInt Max = APIntOps::smax(StartRange.getSignedMax(),
EndRange.getSignedMax());
if (Min.isMinSignedValue() && Max.isMaxSignedValue())
- return ConstantRange(Min.getBitWidth(), /*isFullSet=*/true);
+ return FullSet;
return ConstantRange(Min, Max+1);
}
}
return getIntegerSCEV(0, V->getType());
else if (isa<UndefValue>(V))
return getIntegerSCEV(0, V->getType());
+ else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
+ return GA->mayBeOverridden() ? getUnknown(V) : getSCEV(GA->getAliasee());
else
return getUnknown(V);
- User *U = cast<User>(V);
+ Operator *U = cast<Operator>(V);
switch (Opcode) {
case Instruction::Add:
+ // Don't transfer the NSW and NUW bits from the Add instruction to the
+ // Add expression, because the Instruction may be guarded by control
+ // flow and the no-overflow bits may not be valid for the expression in
+ // any context.
return getAddExpr(getSCEV(U->getOperand(0)),
getSCEV(U->getOperand(1)));
case Instruction::Mul:
+ // Don't transfer the NSW and NUW bits from the Mul instruction to the
+ // Mul expression, as with Add.
return getMulExpr(getSCEV(U->getOperand(0)),
getSCEV(U->getOperand(1)));
case Instruction::UDiv:
if (LZ != 0 && !((~A & ~KnownZero) & EffectiveMask))
return
getZeroExtendExpr(getTruncateExpr(getSCEV(U->getOperand(0)),
- IntegerType::get(BitWidth - LZ)),
+ IntegerType::get(getContext(), BitWidth - LZ)),
U->getType());
}
break;
const SCEV *LHS = getSCEV(U->getOperand(0));
const APInt &CIVal = CI->getValue();
if (GetMinTrailingZeros(LHS) >=
- (CIVal.getBitWidth() - CIVal.countLeadingZeros()))
- return getAddExpr(LHS, getSCEV(U->getOperand(1)));
+ (CIVal.getBitWidth() - CIVal.countLeadingZeros())) {
+ // Build a plain add SCEV.
+ const SCEV *S = getAddExpr(LHS, getSCEV(CI));
+ // If the LHS of the add was an addrec and it has no-wrap flags,
+ // transfer the no-wrap flags, since an or won't introduce a wrap.
+ if (const SCEVAddRecExpr *NewAR = dyn_cast<SCEVAddRecExpr>(S)) {
+ const SCEVAddRecExpr *OldAR = cast<SCEVAddRecExpr>(LHS);
+ if (OldAR->hasNoUnsignedWrap())
+ const_cast<SCEVAddRecExpr *>(NewAR)->setHasNoUnsignedWrap(true);
+ if (OldAR->hasNoSignedWrap())
+ const_cast<SCEVAddRecExpr *>(NewAR)->setHasNoSignedWrap(true);
+ }
+ return S;
+ }
}
break;
case Instruction::Xor:
// Turn shift left of a constant amount into a multiply.
if (ConstantInt *SA = dyn_cast<ConstantInt>(U->getOperand(1))) {
uint32_t BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
- Constant *X = ConstantInt::get(
+ Constant *X = ConstantInt::get(getContext(),
APInt(BitWidth, 1).shl(SA->getLimitedValue(BitWidth)));
return getMulExpr(getSCEV(U->getOperand(0)), getSCEV(X));
}
// Turn logical shift right of a constant into a unsigned divide.
if (ConstantInt *SA = dyn_cast<ConstantInt>(U->getOperand(1))) {
uint32_t BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
- Constant *X = ConstantInt::get(
+ Constant *X = ConstantInt::get(getContext(),
APInt(BitWidth, 1).shl(SA->getLimitedValue(BitWidth)));
return getUDivExpr(getSCEV(U->getOperand(0)), getSCEV(X));
}
return getIntegerSCEV(0, U->getType()); // value is undefined
return
getSignExtendExpr(getTruncateExpr(getSCEV(L->getOperand(0)),
- IntegerType::get(Amt)),
+ IntegerType::get(getContext(), Amt)),
U->getType());
}
break;
return getSCEV(U->getOperand(0));
break;
- case Instruction::IntToPtr:
- if (!TD) break; // Without TD we can't analyze pointers.
- return getTruncateOrZeroExtend(getSCEV(U->getOperand(0)),
- TD->getIntPtrType());
-
- case Instruction::PtrToInt:
- if (!TD) break; // Without TD we can't analyze pointers.
- return getTruncateOrZeroExtend(getSCEV(U->getOperand(0)),
- U->getType());
+ // It's tempting to handle inttoptr and ptrtoint, however this can
+ // lead to pointer expressions which cannot be expanded to GEPs
+ // (because they may overflow). For now, the only pointer-typed
+ // expressions we handle are GEPs and address literals.
case Instruction::GetElementPtr:
- if (!TD) break; // Without TD we can't analyze pointers.
- return createNodeForGEP(U);
+ return createNodeForGEP(cast<GEPOperator>(U));
case Instruction::PHI:
return createNodeForPHI(cast<PHINode>(U));
Worklist.push_back(PN);
}
-/// PushDefUseChildren - Push users of the given Instruction
-/// onto the given Worklist.
-static void
-PushDefUseChildren(Instruction *I,
- SmallVectorImpl<Instruction *> &Worklist) {
- // Push the def-use children onto the Worklist stack.
- for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
- UI != UE; ++UI)
- Worklist.push_back(cast<Instruction>(UI));
-}
-
const ScalarEvolution::BackedgeTakenInfo &
ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
// Initially insert a CouldNotCompute for this loop. If the insertion
// update the value. The temporary CouldNotCompute value tells SCEV
// code elsewhere that it shouldn't attempt to request a new
// backedge-taken count, which could result in infinite recursion.
- std::pair<std::map<const Loop*, BackedgeTakenInfo>::iterator, bool> Pair =
+ std::pair<std::map<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair =
BackedgeTakenCounts.insert(std::make_pair(L, getCouldNotCompute()));
if (Pair.second) {
BackedgeTakenInfo ItCount = ComputeBackedgeTakenCount(L);
// Now that we know more about the trip count for this loop, forget any
// existing SCEV values for PHI nodes in this loop since they are only
// conservative estimates made without the benefit of trip count
- // information. This is similar to the code in
- // forgetLoopBackedgeTakenCount, except that it handles SCEVUnknown PHI
- // nodes specially.
+ // information. This is similar to the code in forgetLoop, except that
+ // it handles SCEVUnknown PHI nodes specially.
if (ItCount.hasAnyInfo()) {
SmallVector<Instruction *, 16> Worklist;
PushLoopPHIs(L, Worklist);
Instruction *I = Worklist.pop_back_val();
if (!Visited.insert(I)) continue;
- std::map<SCEVCallbackVH, const SCEV*>::iterator It =
+ std::map<SCEVCallbackVH, const SCEV *>::iterator It =
Scalars.find(static_cast<Value *>(I));
if (It != Scalars.end()) {
// SCEVUnknown for a PHI either means that it has an unrecognized
// count information isn't going to change anything. In the later
// case, createNodeForPHI will perform the necessary updates on its
// own when it gets to that point.
- if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second))
+ if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second)) {
+ ValuesAtScopes.erase(It->second);
Scalars.erase(It);
- ValuesAtScopes.erase(I);
+ }
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
}
return Pair.first->second;
}
-/// 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 ScalarEvolution::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 ScalarEvolution::forgetLoop(const Loop *L) {
+ // Drop any stored trip count value.
BackedgeTakenCounts.erase(L);
+ // Drop information about expressions based on loop-header PHIs.
SmallVector<Instruction *, 16> Worklist;
PushLoopPHIs(L, Worklist);
Instruction *I = Worklist.pop_back_val();
if (!Visited.insert(I)) continue;
- std::map<SCEVCallbackVH, const SCEV*>::iterator It =
+ std::map<SCEVCallbackVH, const SCEV *>::iterator It =
Scalars.find(static_cast<Value *>(I));
if (It != Scalars.end()) {
+ ValuesAtScopes.erase(It->second);
Scalars.erase(It);
- ValuesAtScopes.erase(I);
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
}
/// of the specified loop will execute.
ScalarEvolution::BackedgeTakenInfo
ScalarEvolution::ComputeBackedgeTakenCount(const Loop *L) {
- SmallVector<BasicBlock*, 8> ExitingBlocks;
+ SmallVector<BasicBlock *, 8> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);
// Examine all exits and pick the most conservative values.
if (!isa<SCEVCouldNotCompute>(TC)) return TC;
break;
}
- case ICmpInst::ICMP_EQ: {
- // Convert to: while (X-Y == 0) // while (X == Y)
+ case ICmpInst::ICMP_EQ: { // while (X == Y)
+ // Convert to: while (X-Y == 0)
const SCEV *TC = HowFarToNonZero(getMinusSCEV(LHS, RHS), L);
if (!isa<SCEVCouldNotCompute>(TC)) return TC;
break;
/// the addressed element of the initializer or null if the index expression is
/// invalid.
static Constant *
-GetAddressedElementFromGlobal(LLVMContext *Context, GlobalVariable *GV,
+GetAddressedElementFromGlobal(GlobalVariable *GV,
const std::vector<ConstantInt*> &Indices) {
Constant *Init = GV->getInitializer();
for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
} else if (isa<ConstantAggregateZero>(Init)) {
if (const StructType *STy = dyn_cast<StructType>(Init->getType())) {
assert(Idx < STy->getNumElements() && "Bad struct index!");
- Init = Context->getNullValue(STy->getElementType(Idx));
+ Init = Constant::getNullValue(STy->getElementType(Idx));
} else if (const ArrayType *ATy = dyn_cast<ArrayType>(Init->getType())) {
if (Idx >= ATy->getNumElements()) return 0; // Bogus program
- Init = Context->getNullValue(ATy->getElementType());
+ Init = Constant::getNullValue(ATy->getElementType());
} else {
- LLVM_UNREACHABLE("Unknown constant aggregate type!");
+ llvm_unreachable("Unknown constant aggregate type!");
}
return 0;
} else {
// Make sure that it is really a constant global we are gepping, with an
// initializer, and make sure the first IDX is really 0.
GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
- if (!GV || !GV->isConstant() || !GV->hasInitializer() ||
+ if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer() ||
GEP->getNumOperands() < 3 || !isa<Constant>(GEP->getOperand(1)) ||
!cast<Constant>(GEP->getOperand(1))->isNullValue())
return getCouldNotCompute();
unsigned MaxSteps = MaxBruteForceIterations;
for (unsigned IterationNum = 0; IterationNum != MaxSteps; ++IterationNum) {
- ConstantInt *ItCst =
- ConstantInt::get(cast<IntegerType>(IdxExpr->getType()), IterationNum);
+ ConstantInt *ItCst = ConstantInt::get(
+ cast<IntegerType>(IdxExpr->getType()), IterationNum);
ConstantInt *Val = EvaluateConstantChrecAtConstant(IdxExpr, ItCst, *this);
// Form the GEP offset.
Indexes[VarIdxNum] = Val;
- Constant *Result = GetAddressedElementFromGlobal(Context, GV, Indexes);
+ Constant *Result = GetAddressedElementFromGlobal(GV, Indexes);
if (Result == 0) break; // Cannot compute!
// Evaluate the condition for this iteration.
// If this is not an instruction, or if this is an instruction outside of the
// loop, it can't be derived from a loop PHI.
Instruction *I = dyn_cast<Instruction>(V);
- if (I == 0 || !L->contains(I->getParent())) return 0;
+ if (I == 0 || !L->contains(I)) return 0;
if (PHINode *PN = dyn_cast<PHINode>(I)) {
if (L->getHeader() == I->getParent())
/// getConstantEvolvingPHI predicate, evaluate its value assuming the PHI node
/// in the loop has the value PHIVal. If we can't fold this expression for some
/// reason, return null.
-static Constant *EvaluateExpression(Value *V, Constant *PHIVal) {
+static Constant *EvaluateExpression(Value *V, Constant *PHIVal,
+ const TargetData *TD) {
if (isa<PHINode>(V)) return PHIVal;
if (Constant *C = dyn_cast<Constant>(V)) return C;
if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) return GV;
Instruction *I = cast<Instruction>(V);
- LLVMContext *Context = I->getParent()->getContext();
std::vector<Constant*> Operands;
Operands.resize(I->getNumOperands());
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
- Operands[i] = EvaluateExpression(I->getOperand(i), PHIVal);
+ Operands[i] = EvaluateExpression(I->getOperand(i), PHIVal, TD);
if (Operands[i] == 0) return 0;
}
if (const CmpInst *CI = dyn_cast<CmpInst>(I))
- return ConstantFoldCompareInstOperands(CI->getPredicate(),
- &Operands[0], Operands.size(),
- Context);
- else
- return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size(),
- Context);
+ return ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
+ Operands[1], TD);
+ return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
+ &Operands[0], Operands.size(), TD);
}
/// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
/// involving constants, fold it.
Constant *
ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
- const APInt& BEs,
+ const APInt &BEs,
const Loop *L) {
std::map<PHINode*, Constant*>::iterator I =
ConstantEvolutionLoopExitValue.find(PN);
return RetVal = PHIVal; // Got exit value!
// Compute the value of the PHI node for the next iteration.
- Constant *NextPHI = EvaluateExpression(BEValue, PHIVal);
+ Constant *NextPHI = EvaluateExpression(BEValue, PHIVal, TD);
if (NextPHI == PHIVal)
return RetVal = NextPHI; // Stopped evolving!
if (NextPHI == 0)
}
}
-/// ComputeBackedgeTakenCountExhaustively - If the trip is known to execute a
+/// 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
for (Constant *PHIVal = StartCST;
IterationNum != MaxIterations; ++IterationNum) {
ConstantInt *CondVal =
- dyn_cast_or_null<ConstantInt>(EvaluateExpression(Cond, PHIVal));
+ dyn_cast_or_null<ConstantInt>(EvaluateExpression(Cond, PHIVal, TD));
// Couldn't symbolically evaluate.
if (!CondVal) return getCouldNotCompute();
if (CondVal->getValue() == uint64_t(ExitWhen)) {
++NumBruteForceTripCountsComputed;
- return getConstant(Type::Int32Ty, IterationNum);
+ return getConstant(Type::getInt32Ty(getContext()), IterationNum);
}
// Compute the value of the PHI node for the next iteration.
- Constant *NextPHI = EvaluateExpression(BEValue, PHIVal);
+ Constant *NextPHI = EvaluateExpression(BEValue, PHIVal, TD);
if (NextPHI == 0 || NextPHI == PHIVal)
return getCouldNotCompute();// Couldn't evaluate or not making progress...
PHIVal = NextPHI;
return getCouldNotCompute();
}
-/// 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.
/// In the case that a relevant loop exit value cannot be computed, the
/// original value V is returned.
const SCEV *ScalarEvolution::getSCEVAtScope(const SCEV *V, const Loop *L) {
- // FIXME: this should be turned into a virtual method on SCEV!
+ // Check to see if we've folded this expression at this loop before.
+ std::map<const Loop *, const SCEV *> &Values = ValuesAtScopes[V];
+ std::pair<std::map<const Loop *, const SCEV *>::iterator, bool> Pair =
+ Values.insert(std::make_pair(L, static_cast<const SCEV *>(0)));
+ if (!Pair.second)
+ return Pair.first->second ? Pair.first->second : V;
+ // Otherwise compute it.
+ const SCEV *C = computeSCEVAtScope(V, L);
+ ValuesAtScopes[V][L] = C;
+ return C;
+}
+
+const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) {
if (isa<SCEVConstant>(V)) return V;
// If this instruction is evolved from a constant-evolving PHI, compute the
// the arguments into constants, and if so, try to constant propagate the
// result. This is particularly useful for computing loop exit values.
if (CanConstantFold(I)) {
- // Check to see if we've folded this instruction at this loop before.
- std::map<const Loop *, Constant *> &Values = ValuesAtScopes[I];
- std::pair<std::map<const Loop *, Constant *>::iterator, bool> Pair =
- Values.insert(std::make_pair(L, static_cast<Constant *>(0)));
- if (!Pair.second)
- return Pair.first->second ? &*getSCEV(Pair.first->second) : V;
-
std::vector<Constant*> Operands;
Operands.reserve(I->getNumOperands());
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
if (!isSCEVable(Op->getType()))
return V;
- const SCEV* OpV = getSCEVAtScope(Op, L);
+ const SCEV *OpV = getSCEVAtScope(Op, L);
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(OpV)) {
Constant *C = SC->getValue();
if (C->getType() != Op->getType())
Constant *C;
if (const CmpInst *CI = dyn_cast<CmpInst>(I))
C = ConstantFoldCompareInstOperands(CI->getPredicate(),
- &Operands[0], Operands.size(),
- Context);
+ Operands[0], Operands[1], TD);
else
C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size(), Context);
- Pair.first->second = C;
+ &Operands[0], Operands.size(), TD);
return getSCEV(C);
}
}
return getSMaxExpr(NewOps);
if (isa<SCEVUMaxExpr>(Comm))
return getUMaxExpr(NewOps);
- LLVM_UNREACHABLE("Unknown commutative SCEV type!");
+ llvm_unreachable("Unknown commutative SCEV type!");
}
}
// If we got here, all operands are loop invariant.
// If this is a loop recurrence for a loop that does not contain L, then we
// are dealing with the final value computed by the loop.
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {
- if (!L || !AddRec->getLoop()->contains(L->getHeader())) {
+ if (!L || !AddRec->getLoop()->contains(L)) {
// To evaluate this recurrence, we need to know how many times the AddRec
// loop iterates. Compute this now.
const SCEV *BackedgeTakenCount = getBackedgeTakenCount(AddRec->getLoop());
return getTruncateExpr(Op, Cast->getType());
}
- LLVM_UNREACHABLE("Unknown SCEV type!");
+ if (isa<SCEVTargetDataConstant>(V))
+ return V;
+
+ llvm_unreachable("Unknown SCEV type!");
return 0;
}
return std::make_pair(CNC, CNC);
}
- LLVMContext *Context = SE.getContext();
+ LLVMContext &Context = SE.getContext();
ConstantInt *Solution1 =
- Context->getConstantInt((NegB + SqrtVal).sdiv(TwoA));
+ ConstantInt::get(Context, (NegB + SqrtVal).sdiv(TwoA));
ConstantInt *Solution2 =
- Context->getConstantInt((NegB - SqrtVal).sdiv(TwoA));
+ ConstantInt::get(Context, (NegB - SqrtVal).sdiv(TwoA));
return std::make_pair(SE.getConstant(Solution1),
SE.getConstant(Solution2));
// First, handle unitary steps.
if (StepC->getValue()->equalsInt(1)) // 1*N = -Start (mod 2^BW), so:
- return getNegativeSCEV(Start); // N = -Start (as unsigned)
+ return getNegativeSCEV(Start); // N = -Start (as unsigned)
if (StepC->getValue()->isAllOnesValue()) // -1*N = -Start (mod 2^BW), so:
return Start; // N = Start (as unsigned)
#endif
// Pick the smallest positive root value.
if (ConstantInt *CB =
- dyn_cast<ConstantInt>(Context->getConstantExprICmp(ICmpInst::ICMP_ULT,
+ dyn_cast<ConstantInt>(ConstantExpr::getICmp(ICmpInst::ICMP_ULT,
R1->getValue(), R2->getValue()))) {
if (CB->getZExtValue() == false)
std::swap(R1, R2); // R1 is the minimum root now.
if (const SCEVUnknown *BU = dyn_cast<SCEVUnknown>(B))
if (const Instruction *AI = dyn_cast<Instruction>(AU->getValue()))
if (const Instruction *BI = dyn_cast<Instruction>(BU->getValue()))
- if (AI->isIdenticalTo(BI))
+ if (AI->isIdenticalTo(BI) && !AI->mayReadFromMemory())
return true;
// Otherwise assume they may have a different value.
switch (Pred) {
default:
- assert(0 && "Unexpected ICmpInst::Predicate value!");
+ llvm_unreachable("Unexpected ICmpInst::Predicate value!");
break;
case ICmpInst::ICMP_SGT:
Pred = ICmpInst::ICMP_SLT;
return true;
if (LHSRange.getSignedMin().sge(RHSRange.getSignedMax()))
return false;
-
- const SCEV *Diff = getMinusSCEV(LHS, RHS);
- ConstantRange DiffRange = getUnsignedRange(Diff);
- if (isKnownNegative(Diff)) {
- if (DiffRange.getUnsignedMax().ult(LHSRange.getUnsignedMin()))
- return true;
- if (DiffRange.getUnsignedMin().uge(LHSRange.getUnsignedMax()))
- return false;
- } else if (isKnownPositive(Diff)) {
- if (LHSRange.getUnsignedMax().ult(DiffRange.getUnsignedMin()))
- return true;
- if (LHSRange.getUnsignedMin().uge(DiffRange.getUnsignedMax()))
- return false;
- }
break;
}
case ICmpInst::ICMP_SGE:
return true;
if (LHSRange.getSignedMin().sgt(RHSRange.getSignedMax()))
return false;
-
- const SCEV *Diff = getMinusSCEV(LHS, RHS);
- ConstantRange DiffRange = getUnsignedRange(Diff);
- if (isKnownNonPositive(Diff)) {
- if (DiffRange.getUnsignedMax().ule(LHSRange.getUnsignedMin()))
- return true;
- if (DiffRange.getUnsignedMin().ugt(LHSRange.getUnsignedMax()))
- return false;
- } else if (isKnownNonNegative(Diff)) {
- if (LHSRange.getUnsignedMax().ule(DiffRange.getUnsignedMin()))
- return true;
- if (LHSRange.getUnsignedMin().ugt(DiffRange.getUnsignedMax()))
- return false;
- }
break;
}
case ICmpInst::ICMP_UGT:
return true;
if (LHSRange.getUnsignedMin().uge(RHSRange.getUnsignedMax()))
return false;
-
- const SCEV *Diff = getMinusSCEV(LHS, RHS);
- ConstantRange DiffRange = getUnsignedRange(Diff);
- if (LHSRange.getUnsignedMax().ult(DiffRange.getUnsignedMin()))
- return true;
- if (LHSRange.getUnsignedMin().uge(DiffRange.getUnsignedMax()))
- return false;
break;
}
case ICmpInst::ICMP_UGE:
return true;
if (LHSRange.getUnsignedMin().ugt(RHSRange.getUnsignedMax()))
return false;
-
- const SCEV *Diff = getMinusSCEV(LHS, RHS);
- ConstantRange DiffRange = getUnsignedRange(Diff);
- if (LHSRange.getUnsignedMax().ule(DiffRange.getUnsignedMin()))
- return true;
- if (LHSRange.getUnsignedMin().ugt(DiffRange.getUnsignedMax()))
- return false;
break;
}
case ICmpInst::ICMP_NE: {
break;
}
case ICmpInst::ICMP_EQ:
+ // The check at the top of the function catches the case where
+ // the values are known to be equal.
break;
}
return false;
LoopContinuePredicate->isUnconditional())
return false;
- return
- isNecessaryCond(LoopContinuePredicate->getCondition(), Pred, LHS, RHS,
- LoopContinuePredicate->getSuccessor(0) != L->getHeader());
+ return isImpliedCond(LoopContinuePredicate->getCondition(), Pred, LHS, RHS,
+ LoopContinuePredicate->getSuccessor(0) != L->getHeader());
}
/// isLoopGuardedByCond - Test whether entry to the loop is protected
LoopEntryPredicate->isUnconditional())
continue;
- if (isNecessaryCond(LoopEntryPredicate->getCondition(), Pred, LHS, RHS,
- LoopEntryPredicate->getSuccessor(0) != PredecessorDest))
+ if (isImpliedCond(LoopEntryPredicate->getCondition(), Pred, LHS, RHS,
+ LoopEntryPredicate->getSuccessor(0) != PredecessorDest))
return true;
}
return false;
}
-/// 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 ScalarEvolution::isNecessaryCond(Value *CondValue,
- ICmpInst::Predicate Pred,
- const SCEV *LHS, const SCEV *RHS,
- bool Inverse) {
+/// isImpliedCond - Test whether the condition described by Pred, LHS,
+/// and RHS is true whenever the given Cond value evaluates to true.
+bool ScalarEvolution::isImpliedCond(Value *CondValue,
+ ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ bool Inverse) {
// Recursivly handle And and Or conditions.
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(CondValue)) {
if (BO->getOpcode() == Instruction::And) {
if (!Inverse)
- return isNecessaryCond(BO->getOperand(0), Pred, LHS, RHS, Inverse) ||
- isNecessaryCond(BO->getOperand(1), Pred, LHS, RHS, Inverse);
+ return isImpliedCond(BO->getOperand(0), Pred, LHS, RHS, Inverse) ||
+ isImpliedCond(BO->getOperand(1), Pred, LHS, RHS, Inverse);
} else if (BO->getOpcode() == Instruction::Or) {
if (Inverse)
- return isNecessaryCond(BO->getOperand(0), Pred, LHS, RHS, Inverse) ||
- isNecessaryCond(BO->getOperand(1), Pred, LHS, RHS, Inverse);
+ return isImpliedCond(BO->getOperand(0), Pred, LHS, RHS, Inverse) ||
+ isImpliedCond(BO->getOperand(1), Pred, LHS, RHS, Inverse);
}
}
ICmpInst *ICI = dyn_cast<ICmpInst>(CondValue);
if (!ICI) return false;
- // Now that we found a conditional branch that dominates the loop, check to
- // see if it is the comparison we are looking for.
- Value *PreCondLHS = ICI->getOperand(0);
- Value *PreCondRHS = ICI->getOperand(1);
- ICmpInst::Predicate FoundPred;
- if (Inverse)
- FoundPred = ICI->getInversePredicate();
- else
- FoundPred = ICI->getPredicate();
-
- if (FoundPred == Pred)
- ; // An exact match.
- else if (!ICmpInst::isTrueWhenEqual(FoundPred) && Pred == ICmpInst::ICMP_NE) {
- // The actual condition is beyond sufficient.
- FoundPred = ICmpInst::ICMP_NE;
- // NE is symmetric but the original comparison may not be. Swap
- // the operands if necessary so that they match below.
- if (isa<SCEVConstant>(LHS))
- std::swap(PreCondLHS, PreCondRHS);
- } else
- // Check a few special cases.
- switch (FoundPred) {
- case ICmpInst::ICMP_UGT:
- if (Pred == ICmpInst::ICMP_ULT) {
- std::swap(PreCondLHS, PreCondRHS);
- FoundPred = ICmpInst::ICMP_ULT;
- break;
- }
- return false;
- case ICmpInst::ICMP_SGT:
- if (Pred == ICmpInst::ICMP_SLT) {
- std::swap(PreCondLHS, PreCondRHS);
- FoundPred = ICmpInst::ICMP_SLT;
- break;
- }
- return false;
- case ICmpInst::ICMP_NE:
- // Expressions like (x >u 0) are often canonicalized to (x != 0),
- // so check for this case by checking if the NE is comparing against
- // a minimum or maximum constant.
- if (!ICmpInst::isTrueWhenEqual(Pred))
- if (const SCEVConstant *C = dyn_cast<SCEVConstant>(RHS)) {
- const APInt &A = C->getValue()->getValue();
- switch (Pred) {
- case ICmpInst::ICMP_SLT:
- if (A.isMaxSignedValue()) break;
- return false;
- case ICmpInst::ICMP_SGT:
- if (A.isMinSignedValue()) break;
- return false;
- case ICmpInst::ICMP_ULT:
- if (A.isMaxValue()) break;
- return false;
- case ICmpInst::ICMP_UGT:
- if (A.isMinValue()) break;
- return false;
- default:
- return false;
- }
- FoundPred = Pred;
- // NE is symmetric but the original comparison may not be. Swap
- // the operands if necessary so that they match below.
- if (isa<SCEVConstant>(LHS))
- std::swap(PreCondLHS, PreCondRHS);
- break;
- }
- return false;
- default:
- // We weren't able to reconcile the condition.
- return false;
- }
-
- assert(Pred == FoundPred && "Conditions were not reconciled!");
-
// Bail if the ICmp's operands' types are wider than the needed type
// before attempting to call getSCEV on them. This avoids infinite
// recursion, since the analysis of widening casts can require loop
// exit condition information for overflow checking, which would
// lead back here.
if (getTypeSizeInBits(LHS->getType()) <
- getTypeSizeInBits(PreCondLHS->getType()))
+ getTypeSizeInBits(ICI->getOperand(0)->getType()))
return false;
- const SCEV *FoundLHS = getSCEV(PreCondLHS);
- const SCEV *FoundRHS = getSCEV(PreCondRHS);
+ // Now that we found a conditional branch that dominates the loop, check to
+ // see if it is the comparison we are looking for.
+ ICmpInst::Predicate FoundPred;
+ if (Inverse)
+ FoundPred = ICI->getInversePredicate();
+ else
+ FoundPred = ICI->getPredicate();
+
+ const SCEV *FoundLHS = getSCEV(ICI->getOperand(0));
+ const SCEV *FoundRHS = getSCEV(ICI->getOperand(1));
// Balance the types. The case where FoundLHS' type is wider than
// LHS' type is checked for above.
}
}
- return isNecessaryCondOperands(Pred, LHS, RHS,
- FoundLHS, FoundRHS) ||
+ // Canonicalize the query to match the way instcombine will have
+ // canonicalized the comparison.
+ // First, put a constant operand on the right.
+ if (isa<SCEVConstant>(LHS)) {
+ std::swap(LHS, RHS);
+ Pred = ICmpInst::getSwappedPredicate(Pred);
+ }
+ // Then, canonicalize comparisons with boundary cases.
+ if (const SCEVConstant *RC = dyn_cast<SCEVConstant>(RHS)) {
+ const APInt &RA = RC->getValue()->getValue();
+ switch (Pred) {
+ default: llvm_unreachable("Unexpected ICmpInst::Predicate value!");
+ case ICmpInst::ICMP_EQ:
+ case ICmpInst::ICMP_NE:
+ break;
+ case ICmpInst::ICMP_UGE:
+ if ((RA - 1).isMinValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA - 1);
+ break;
+ }
+ if (RA.isMaxValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ break;
+ }
+ if (RA.isMinValue()) return true;
+ break;
+ case ICmpInst::ICMP_ULE:
+ if ((RA + 1).isMaxValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA + 1);
+ break;
+ }
+ if (RA.isMinValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ break;
+ }
+ if (RA.isMaxValue()) return true;
+ break;
+ case ICmpInst::ICMP_SGE:
+ if ((RA - 1).isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA - 1);
+ break;
+ }
+ if (RA.isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ break;
+ }
+ if (RA.isMinSignedValue()) return true;
+ break;
+ case ICmpInst::ICMP_SLE:
+ if ((RA + 1).isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA + 1);
+ break;
+ }
+ if (RA.isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ break;
+ }
+ if (RA.isMaxSignedValue()) return true;
+ break;
+ case ICmpInst::ICMP_UGT:
+ if (RA.isMinValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ break;
+ }
+ if ((RA + 1).isMaxValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA + 1);
+ break;
+ }
+ if (RA.isMaxValue()) return false;
+ break;
+ case ICmpInst::ICMP_ULT:
+ if (RA.isMaxValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ break;
+ }
+ if ((RA - 1).isMinValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA - 1);
+ break;
+ }
+ if (RA.isMinValue()) return false;
+ break;
+ case ICmpInst::ICMP_SGT:
+ if (RA.isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ break;
+ }
+ if ((RA + 1).isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA + 1);
+ break;
+ }
+ if (RA.isMaxSignedValue()) return false;
+ break;
+ case ICmpInst::ICMP_SLT:
+ if (RA.isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ break;
+ }
+ if ((RA - 1).isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA - 1);
+ break;
+ }
+ if (RA.isMinSignedValue()) return false;
+ break;
+ }
+ }
+
+ // Check to see if we can make the LHS or RHS match.
+ if (LHS == FoundRHS || RHS == FoundLHS) {
+ if (isa<SCEVConstant>(RHS)) {
+ std::swap(FoundLHS, FoundRHS);
+ FoundPred = ICmpInst::getSwappedPredicate(FoundPred);
+ } else {
+ std::swap(LHS, RHS);
+ Pred = ICmpInst::getSwappedPredicate(Pred);
+ }
+ }
+
+ // Check whether the found predicate is the same as the desired predicate.
+ if (FoundPred == Pred)
+ return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS);
+
+ // Check whether swapping the found predicate makes it the same as the
+ // desired predicate.
+ if (ICmpInst::getSwappedPredicate(FoundPred) == Pred) {
+ if (isa<SCEVConstant>(RHS))
+ return isImpliedCondOperands(Pred, LHS, RHS, FoundRHS, FoundLHS);
+ else
+ return isImpliedCondOperands(ICmpInst::getSwappedPredicate(Pred),
+ RHS, LHS, FoundLHS, FoundRHS);
+ }
+
+ // Check whether the actual condition is beyond sufficient.
+ if (FoundPred == ICmpInst::ICMP_EQ)
+ if (ICmpInst::isTrueWhenEqual(Pred))
+ if (isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS))
+ return true;
+ if (Pred == ICmpInst::ICMP_NE)
+ if (!ICmpInst::isTrueWhenEqual(FoundPred))
+ if (isImpliedCondOperands(FoundPred, LHS, RHS, FoundLHS, FoundRHS))
+ return true;
+
+ // Otherwise assume the worst.
+ return false;
+}
+
+/// isImpliedCondOperands - Test whether the condition described by Pred,
+/// LHS, and RHS is true whenever the condition desribed by Pred, FoundLHS,
+/// and FoundRHS is true.
+bool ScalarEvolution::isImpliedCondOperands(ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ const SCEV *FoundLHS,
+ const SCEV *FoundRHS) {
+ return isImpliedCondOperandsHelper(Pred, LHS, RHS,
+ FoundLHS, FoundRHS) ||
// ~x < ~y --> x > y
- isNecessaryCondOperands(Pred, LHS, RHS,
- getNotSCEV(FoundRHS), getNotSCEV(FoundLHS));
+ isImpliedCondOperandsHelper(Pred, LHS, RHS,
+ getNotSCEV(FoundRHS),
+ getNotSCEV(FoundLHS));
}
-/// 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.
+/// isImpliedCondOperandsHelper - Test whether the condition described by
+/// Pred, LHS, and RHS is true whenever the condition desribed by Pred,
+/// FoundLHS, and FoundRHS is true.
bool
-ScalarEvolution::isNecessaryCondOperands(ICmpInst::Predicate Pred,
- const SCEV *LHS, const SCEV *RHS,
- const SCEV *FoundLHS,
- const SCEV *FoundRHS) {
+ScalarEvolution::isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ const SCEV *FoundLHS,
+ const SCEV *FoundRHS) {
switch (Pred) {
- default: break;
+ default: llvm_unreachable("Unexpected ICmpInst::Predicate value!");
+ case ICmpInst::ICMP_EQ:
+ case ICmpInst::ICMP_NE:
+ if (HasSameValue(LHS, FoundLHS) && HasSameValue(RHS, FoundRHS))
+ return true;
+ break;
case ICmpInst::ICMP_SLT:
+ case ICmpInst::ICMP_SLE:
if (isKnownPredicate(ICmpInst::ICMP_SLE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_SGE, RHS, FoundRHS))
return true;
break;
case ICmpInst::ICMP_SGT:
+ case ICmpInst::ICMP_SGE:
if (isKnownPredicate(ICmpInst::ICMP_SGE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_SLE, RHS, FoundRHS))
return true;
break;
case ICmpInst::ICMP_ULT:
+ case ICmpInst::ICMP_ULE:
if (isKnownPredicate(ICmpInst::ICMP_ULE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_UGE, RHS, FoundRHS))
return true;
break;
case ICmpInst::ICMP_UGT:
+ case ICmpInst::ICMP_UGE:
if (isKnownPredicate(ICmpInst::ICMP_UGE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_ULE, RHS, FoundRHS))
return true;
/// CouldNotCompute if an intermediate computation overflows.
const SCEV *ScalarEvolution::getBECount(const SCEV *Start,
const SCEV *End,
- const SCEV *Step) {
+ const SCEV *Step,
+ bool NoWrap) {
const Type *Ty = Start->getType();
const SCEV *NegOne = getIntegerSCEV(-1, Ty);
const SCEV *Diff = getMinusSCEV(End, Start);
// the division will effectively round up.
const SCEV *Add = getAddExpr(Diff, RoundUp);
- // Check Add for unsigned overflow.
- // TODO: More sophisticated things could be done here.
- const Type *WideTy = Context->getIntegerType(getTypeSizeInBits(Ty) + 1);
- const SCEV *EDiff = getZeroExtendExpr(Diff, WideTy);
- const SCEV *ERoundUp = getZeroExtendExpr(RoundUp, WideTy);
- const SCEV *OperandExtendedAdd = getAddExpr(EDiff, ERoundUp);
- if (getZeroExtendExpr(Add, WideTy) != OperandExtendedAdd)
- return getCouldNotCompute();
+ if (!NoWrap) {
+ // Check Add for unsigned overflow.
+ // TODO: More sophisticated things could be done here.
+ const Type *WideTy = IntegerType::get(getContext(),
+ getTypeSizeInBits(Ty) + 1);
+ const SCEV *EDiff = getZeroExtendExpr(Diff, WideTy);
+ const SCEV *ERoundUp = getZeroExtendExpr(RoundUp, WideTy);
+ const SCEV *OperandExtendedAdd = getAddExpr(EDiff, ERoundUp);
+ if (getZeroExtendExpr(Add, WideTy) != OperandExtendedAdd)
+ return getCouldNotCompute();
+ }
return getUDivExpr(Add, Step);
}
if (!AddRec || AddRec->getLoop() != L)
return getCouldNotCompute();
+ // Check to see if we have a flag which makes analysis easy.
+ bool NoWrap = isSigned ? AddRec->hasNoSignedWrap() :
+ AddRec->hasNoUnsignedWrap();
+
if (AddRec->isAffine()) {
// FORNOW: We only support unit strides.
unsigned BitWidth = getTypeSizeInBits(AddRec->getType());
if (CStep->isOne()) {
// With unit stride, the iteration never steps past the limit value.
} else if (CStep->getValue()->getValue().isStrictlyPositive()) {
- if (const SCEVConstant *CLimit = dyn_cast<SCEVConstant>(RHS)) {
+ if (NoWrap) {
+ // We know the iteration won't step past the maximum value for its type.
+ ;
+ } else if (const SCEVConstant *CLimit = dyn_cast<SCEVConstant>(RHS)) {
// Test whether a positive iteration iteration can step past the limit
// value and past the maximum value for its type in a single step.
if (isSigned) {
// Finally, we subtract these two values and divide, rounding up, to get
// the number of times the backedge is executed.
- const SCEV *BECount = getBECount(Start, End, Step);
+ const SCEV *BECount = getBECount(Start, End, Step, NoWrap);
// The maximum backedge count is similar, except using the minimum start
// value and the maximum end value.
- const SCEV *MaxBECount = getBECount(MinStart, MaxEnd, Step);
+ const SCEV *MaxBECount = getBECount(MinStart, MaxEnd, Step, NoWrap);
return BackedgeTakenInfo(BECount, MaxBECount);
}
// The exit value should be (End+A)/A.
APInt ExitVal = (End + A).udiv(A);
- ConstantInt *ExitValue = SE.getContext()->getConstantInt(ExitVal);
+ ConstantInt *ExitValue = ConstantInt::get(SE.getContext(), ExitVal);
// Evaluate at the exit value. If we really did fall out of the valid
// range, then we computed our trip count, otherwise wrap around or other
// Ensure that the previous value is in the range. This is a sanity check.
assert(Range.contains(
EvaluateConstantChrecAtConstant(this,
- SE.getContext()->getConstantInt(ExitVal - One), SE)->getValue()) &&
+ ConstantInt::get(SE.getContext(), ExitVal - One), SE)->getValue()) &&
"Linear scev computation is off in a bad way!");
return SE.getConstant(ExitValue);
} else if (isQuadratic()) {
if (R1) {
// Pick the smallest positive root value.
if (ConstantInt *CB =
- dyn_cast<ConstantInt>(
- SE.getContext()->getConstantExprICmp(ICmpInst::ICMP_ULT,
+ dyn_cast<ConstantInt>(ConstantExpr::getICmp(ICmpInst::ICMP_ULT,
R1->getValue(), R2->getValue()))) {
if (CB->getZExtValue() == false)
std::swap(R1, R2); // R1 is the minimum root now.
if (Range.contains(R1Val->getValue())) {
// The next iteration must be out of the range...
ConstantInt *NextVal =
- SE.getContext()->getConstantInt(R1->getValue()->getValue()+1);
+ ConstantInt::get(SE.getContext(), R1->getValue()->getValue()+1);
R1Val = EvaluateConstantChrecAtConstant(this, NextVal, SE);
if (!Range.contains(R1Val->getValue()))
// If R1 was not in the range, then it is a good return value. Make
// sure that R1-1 WAS in the range though, just in case.
ConstantInt *NextVal =
- SE.getContext()->getConstantInt(R1->getValue()->getValue()-1);
+ ConstantInt::get(SE.getContext(), R1->getValue()->getValue()-1);
R1Val = EvaluateConstantChrecAtConstant(this, NextVal, SE);
if (Range.contains(R1Val->getValue()))
return R1;
assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!");
if (PHINode *PN = dyn_cast<PHINode>(getValPtr()))
SE->ConstantEvolutionLoopExitValue.erase(PN);
- if (Instruction *I = dyn_cast<Instruction>(getValPtr()))
- SE->ValuesAtScopes.erase(I);
SE->Scalars.erase(getValPtr());
// this now dangles!
}
// so that future queries will recompute the expressions using the new
// value.
SmallVector<User *, 16> Worklist;
+ SmallPtrSet<User *, 8> Visited;
Value *Old = getValPtr();
bool DeleteOld = false;
for (Value::use_iterator UI = Old->use_begin(), UE = Old->use_end();
DeleteOld = true;
continue;
}
+ if (!Visited.insert(U))
+ continue;
if (PHINode *PN = dyn_cast<PHINode>(U))
SE->ConstantEvolutionLoopExitValue.erase(PN);
- if (Instruction *I = dyn_cast<Instruction>(U))
- SE->ValuesAtScopes.erase(I);
- if (SE->Scalars.erase(U))
- for (Value::use_iterator UI = U->use_begin(), UE = U->use_end();
- UI != UE; ++UI)
- Worklist.push_back(*UI);
+ SE->Scalars.erase(U);
+ for (Value::use_iterator UI = U->use_begin(), UE = U->use_end();
+ UI != UE; ++UI)
+ Worklist.push_back(*UI);
}
+ // Delete the Old value if it (indirectly) references itself.
if (DeleteOld) {
if (PHINode *PN = dyn_cast<PHINode>(Old))
SE->ConstantEvolutionLoopExitValue.erase(PN);
- if (Instruction *I = dyn_cast<Instruction>(Old))
- SE->ValuesAtScopes.erase(I);
SE->Scalars.erase(Old);
// this now dangles!
}
OS << "Loop " << L->getHeader()->getName() << ": ";
- SmallVector<BasicBlock*, 8> ExitBlocks;
+ SmallVector<BasicBlock *, 8> ExitBlocks;
L->getExitBlocks(ExitBlocks);
if (ExitBlocks.size() != 1)
OS << "<multiple exits> ";
OS << "\n";
}
-void ScalarEvolution::print(raw_ostream &OS, const Module* ) const {
+void ScalarEvolution::print(raw_ostream &OS, const Module *) const {
// ScalarEvolution's implementaiton of the print method is to print
// out SCEV values of all instructions that are interesting. Doing
// this potentially causes it to create new SCEV objects though,
// which technically conflicts with the const qualifier. This isn't
// observable from outside the class though, so casting away the
// const isn't dangerous.
- ScalarEvolution &SE = *const_cast<ScalarEvolution*>(this);
+ ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this);
OS << "Classifying expressions for: " << F->getName() << "\n";
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
PrintLoopInfo(OS, &SE, *I);
}
-void ScalarEvolution::print(std::ostream &o, const Module *M) const {
- raw_os_ostream OS(o);
- print(OS, M);
-}
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