#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/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/InstIterator.h"
SCEV::~SCEV() {}
void SCEV::dump() const {
- print(errs());
- errs() << '\n';
+ print(dbgs());
+ dbgs() << '\n';
}
bool SCEV::isZero() const {
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) {
return true;
}
+bool SCEVNAryExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+ if (!getOperand(i)->properlyDominates(BB, DT))
+ return false;
+ }
+ return true;
+}
+
bool SCEVUDivExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
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 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 << "{" << *Operands[0];
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
OS << ",+," << *Operands[i];
- 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 << ")";
+ OS << "}<";
+ WriteAsOperand(OS, L->getHeader(), /*PrintType=*/false);
+ OS << ">";
}
bool SCEVUnknown::isLoopInvariant(const Loop *L) const {
// 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();
}
+bool SCEVUnknown::isSizeOf(const Type *&AllocTy) const {
+ if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(V))
+ if (VCE->getOpcode() == Instruction::PtrToInt)
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
+ if (CE->getOpcode() == Instruction::GetElementPtr &&
+ CE->getOperand(0)->isNullValue() &&
+ CE->getNumOperands() == 2)
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(1)))
+ if (CI->isOne()) {
+ AllocTy = cast<PointerType>(CE->getOperand(0)->getType())
+ ->getElementType();
+ return true;
+ }
+
+ return false;
+}
+
+bool SCEVUnknown::isAlignOf(const Type *&AllocTy) const {
+ if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(V))
+ if (VCE->getOpcode() == Instruction::PtrToInt)
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
+ if (CE->getOpcode() == Instruction::GetElementPtr &&
+ CE->getOperand(0)->isNullValue()) {
+ const Type *Ty =
+ cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
+ if (const StructType *STy = dyn_cast<StructType>(Ty))
+ if (!STy->isPacked() &&
+ CE->getNumOperands() == 3 &&
+ CE->getOperand(1)->isNullValue()) {
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(2)))
+ if (CI->isOne() &&
+ STy->getNumElements() == 2 &&
+ STy->getElementType(0)->isInteger(1)) {
+ AllocTy = STy->getElementType(1);
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
+bool SCEVUnknown::isOffsetOf(const Type *&CTy, Constant *&FieldNo) const {
+ if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(V))
+ if (VCE->getOpcode() == Instruction::PtrToInt)
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
+ if (CE->getOpcode() == Instruction::GetElementPtr &&
+ CE->getNumOperands() == 3 &&
+ CE->getOperand(0)->isNullValue() &&
+ CE->getOperand(1)->isNullValue()) {
+ const Type *Ty =
+ cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
+ // Ignore vector types here so that ScalarEvolutionExpander doesn't
+ // emit getelementptrs that index into vectors.
+ if (isa<StructType>(Ty) || isa<ArrayType>(Ty)) {
+ CTy = Ty;
+ FieldNo = CE->getOperand(2);
+ return true;
+ }
+ }
+
+ return false;
+}
+
void SCEVUnknown::print(raw_ostream &OS) const {
+ const Type *AllocTy;
+ if (isSizeOf(AllocTy)) {
+ OS << "sizeof(" << *AllocTy << ")";
+ return;
+ }
+ if (isAlignOf(AllocTy)) {
+ OS << "alignof(" << *AllocTy << ")";
+ return;
+ }
+
+ const Type *CTy;
+ Constant *FieldNo;
+ if (isOffsetOf(CTy, FieldNo)) {
+ OS << "offsetof(" << *CTy << ", ";
+ WriteAsOperand(OS, FieldNo, false);
+ OS << ")";
+ return;
+ }
+
+ // Otherwise just print it normally.
WriteAsOperand(OS, V, false);
}
/// 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) {}
return operator()(LC->getOperand(), RC->getOperand());
}
- // 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;
}
if (!isa<SCEVSignExtendExpr>(SExt))
return SExt;
+ // Force the cast to be folded into the operands of an addrec.
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) {
+ SmallVector<const SCEV *, 4> Ops;
+ for (SCEVAddRecExpr::op_iterator I = AR->op_begin(), E = AR->op_end();
+ I != E; ++I)
+ Ops.push_back(getAnyExtendExpr(*I, Ty));
+ return getAddRecExpr(Ops, AR->getLoop());
+ }
+
// If the expression is obviously signed, use the sext cast value.
if (isa<SCEVSMaxExpr>(Op))
return SExt;
/// 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
"SCEVAddExpr operand types don't match!");
#endif
+ // If HasNSW is true and all the operands are non-negative, infer HasNUW.
+ if (!HasNUW && HasNSW) {
+ bool All = true;
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i)
+ if (!isKnownNonNegative(Ops[i])) {
+ All = false;
+ break;
+ }
+ if (All) HasNUW = true;
+ }
+
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops, LI);
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;
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
void *IP = 0;
- if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVAddExpr>();
- new (S) SCEVAddExpr(ID, Ops);
- UniqueSCEVs.InsertNode(S, IP);
+ SCEVAddExpr *S =
+ static_cast<SCEVAddExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
+ if (!S) {
+ 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!");
+ if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
assert(getEffectiveSCEVType(Ops[i]->getType()) ==
"SCEVMulExpr operand types don't match!");
#endif
+ // If HasNSW is true and all the operands are non-negative, infer HasNUW.
+ if (!HasNUW && HasNSW) {
+ bool All = true;
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i)
+ if (!isKnownNonNegative(Ops[i])) {
+ All = false;
+ break;
+ }
+ if (All) HasNUW = true;
+ }
+
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops, LI);
return getAddExpr(getMulExpr(LHSC, Add->getOperand(0)),
getMulExpr(LHSC, Add->getOperand(1)));
-
++Idx;
while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
// We found two constants, fold them together!
} else if (cast<SCEVConstant>(Ops[0])->getValue()->isZero()) {
// If we have a multiply of zero, it will always be zero.
return Ops[0];
+ } else if (Ops[0]->isAllOnesValue()) {
+ // If we have a mul by -1 of an add, try distributing the -1 among the
+ // add operands.
+ if (Ops.size() == 2)
+ if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) {
+ SmallVector<const SCEV *, 4> NewOps;
+ bool AnyFolded = false;
+ for (SCEVAddRecExpr::op_iterator I = Add->op_begin(), E = Add->op_end();
+ I != E; ++I) {
+ const SCEV *Mul = getMulExpr(Ops[0], *I);
+ if (!isa<SCEVMulExpr>(Mul)) AnyFolded = true;
+ NewOps.push_back(Mul);
+ }
+ if (AnyFolded)
+ return getAddExpr(NewOps);
+ }
}
}
}
}
- const SCEV *NewRec = getAddRecExpr(NewOps, AddRec->getLoop());
+ // 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(),
+ HasNUW && AddRec->hasNoUnsignedWrap(),
+ /*HasNSW=*/false);
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
void *IP = 0;
- if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVMulExpr>();
- new (S) SCEVMulExpr(ID, Ops);
- UniqueSCEVs.InsertNode(S, IP);
+ SCEVMulExpr *S =
+ static_cast<SCEVMulExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
+ if (!S) {
+ 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;
}
/// 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
+ }
+
+ // If HasNSW is true and all the operands are non-negative, infer HasNUW.
+ if (!HasNUW && HasNSW) {
+ bool All = true;
+ for (unsigned i = 0, e = Operands.size(); i != e; ++i)
+ if (!isKnownNonNegative(Operands[i])) {
+ All = false;
+ break;
+ }
+ if (All) HasNUW = true;
}
// 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();
- if (L->getLoopDepth() < NestedLoop->getLoopDepth()) {
+ const Loop *NestedLoop = NestedAR->getLoop();
+ if (L->contains(NestedLoop->getHeader()) ?
+ (L->getLoopDepth() < NestedLoop->getLoopDepth()) :
+ (!NestedLoop->contains(L->getHeader()) &&
+ DT->dominates(L->getHeader(), NestedLoop->getHeader()))) {
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;
}
}
+ // Okay, it looks like we really DO need an addrec expr. Check to see if we
+ // already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scAddRecExpr);
ID.AddInteger(Operands.size());
ID.AddPointer(Operands[i]);
ID.AddPointer(L);
void *IP = 0;
- if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVAddRecExpr>();
- new (S) SCEVAddRecExpr(ID, Operands, L);
- UniqueSCEVs.InsertNode(S, IP);
+ SCEVAddRecExpr *S =
+ static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
+ if (!S) {
+ 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;
}
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);
- }
+const SCEV *ScalarEvolution::getSizeOfExpr(const Type *AllocTy) {
+ Constant *C = ConstantExpr::getSizeOf(AllocTy);
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
+ C = ConstantFoldConstantExpression(CE, TD);
+ const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
+ return getTruncateOrZeroExtend(getSCEV(C), Ty);
+}
- // Field 0 is always at offset 0.
- if (FieldNo == 0) {
- const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
- return getIntegerSCEV(0, Ty);
- }
+const SCEV *ScalarEvolution::getAlignOfExpr(const Type *AllocTy) {
+ Constant *C = ConstantExpr::getAlignOf(AllocTy);
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
+ C = ConstantFoldConstantExpression(CE, TD);
+ const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
+ return getTruncateOrZeroExtend(getSCEV(C), 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 SCEV *ScalarEvolution::getOffsetOfExpr(const StructType *STy,
+ unsigned FieldNo) {
+ Constant *C = ConstantExpr::getOffsetOf(STy, FieldNo);
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
+ C = ConstantFoldConstantExpression(CE, TD);
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
- new (S) SCEVFieldOffsetExpr(ID, Ty, STy, FieldNo);
- UniqueSCEVs.InsertNode(S, IP);
- return S;
+ return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
-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::getOffsetOfExpr(const Type *CTy,
+ Constant *FieldNo) {
+ Constant *C = ConstantExpr::getOffsetOf(CTy, FieldNo);
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
+ C = ConstantFoldConstantExpression(CE, TD);
+ const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(CTy));
+ return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
const SCEV *ScalarEvolution::getUnknown(Value *V) {
/// getIntegerSCEV - Given a SCEVable type, create a constant for the
/// specified signed integer value and return a SCEV for the constant.
-const SCEV *ScalarEvolution::getIntegerSCEV(int Val, const Type *Ty) {
+const SCEV *ScalarEvolution::getIntegerSCEV(int64_t Val, const Type *Ty) {
const IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
return getConstant(ConstantInt::get(ITy, Val));
}
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()) {
// Short-circuit the def-use traversal if the symbolic name
if (Accum->isLoopInvariant(L) ||
(isa<SCEVAddRecExpr>(Accum) &&
cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) {
+ bool HasNUW = false;
+ bool HasNSW = false;
+
+ // 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->hasNoUnsignedWrap())
+ HasNUW = true;
+ if (OBO->hasNoSignedWrap())
+ HasNSW = true;
+ }
+
const SCEV *StartVal =
getSCEV(PN->getIncomingValue(IncomingEdge));
- 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);
- }
- }
+ const SCEV *PHISCEV =
+ getAddRecExpr(StartVal, Accum, L, HasNUW, HasNSW);
+
+ // Since the no-wrap flags are on the increment, they apply to the
+ // post-incremented value as well.
+ if (Accum->isLoopInvariant(L))
+ (void)getAddRecExpr(getAddExpr(StartVal, Accum),
+ Accum, L, HasNUW, HasNSW);
// Okay, for the entire analysis of this edge we assumed the PHI
// to be symbolic. We now need to go back and purge all of the
/// createNodeForGEP - Expand GEP instructions into add and multiply
/// operations. This allows them to be analyzed by regular SCEV code.
///
-const SCEV *ScalarEvolution::createNodeForGEP(Operator *GEP) {
+const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) {
+ bool InBounds = GEP->isInBounds();
const Type *IntPtrTy = getEffectiveSCEVType(GEP->getType());
Value *Base = GEP->getOperand(0);
// Don't attempt to analyze GEPs over unsized objects.
// For a struct, add the member offset.
unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
TotalOffset = getAddExpr(TotalOffset,
- getFieldOffsetExpr(STy, FieldNo));
+ getOffsetOfExpr(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, getAllocSizeExpr(*GTI));
- TotalOffset = getAddExpr(TotalOffset, LocalOffset);
+ // Getelementptr indicies are signed.
+ LocalOffset = getTruncateOrSignExtend(LocalOffset, IntPtrTy);
+ // Lower "inbounds" GEPs to NSW arithmetic.
+ LocalOffset = getMulExpr(LocalOffset, getSizeOfExpr(*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
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
return ConstantRange(C->getValue()->getValue());
+ unsigned BitWidth = getTypeSizeInBits(S->getType());
+ ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
+
+ // If the value has known zeros, the maximum unsigned value will have those
+ // known zeros as well.
+ uint32_t TZ = GetMinTrailingZeros(S);
+ if (TZ != 0)
+ ConservativeResult =
+ ConstantRange(APInt::getMinValue(BitWidth),
+ APInt::getMaxValue(BitWidth).lshr(TZ).shl(TZ) + 1);
+
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
ConstantRange X = getUnsignedRange(Add->getOperand(0));
for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i)
X = X.add(getUnsignedRange(Add->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
ConstantRange X = getUnsignedRange(Mul->getOperand(0));
for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i)
X = X.multiply(getUnsignedRange(Mul->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) {
ConstantRange X = getUnsignedRange(SMax->getOperand(0));
for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i)
X = X.smax(getUnsignedRange(SMax->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) {
ConstantRange X = getUnsignedRange(UMax->getOperand(0));
for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i)
X = X.umax(getUnsignedRange(UMax->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
ConstantRange X = getUnsignedRange(UDiv->getLHS());
ConstantRange Y = getUnsignedRange(UDiv->getRHS());
- return X.udiv(Y);
+ return ConservativeResult.intersectWith(X.udiv(Y));
}
if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
ConstantRange X = getUnsignedRange(ZExt->getOperand());
- return X.zeroExtend(cast<IntegerType>(ZExt->getType())->getBitWidth());
+ return ConservativeResult.intersectWith(X.zeroExtend(BitWidth));
}
if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
ConstantRange X = getUnsignedRange(SExt->getOperand());
- return X.signExtend(cast<IntegerType>(SExt->getType())->getBitWidth());
+ return ConservativeResult.intersectWith(X.signExtend(BitWidth));
}
if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
ConstantRange X = getUnsignedRange(Trunc->getOperand());
- return X.truncate(cast<IntegerType>(Trunc->getType())->getBitWidth());
+ return ConservativeResult.intersectWith(X.truncate(BitWidth));
}
- ConstantRange FullSet(getTypeSizeInBits(S->getType()), true);
-
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
- const SCEV *T = getBackedgeTakenCount(AddRec->getLoop());
- const SCEVConstant *Trip = dyn_cast<SCEVConstant>(T);
- if (!Trip) return FullSet;
+ // If there's no unsigned wrap, the value will never be less than its
+ // initial value.
+ if (AddRec->hasNoUnsignedWrap())
+ if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart()))
+ ConservativeResult =
+ ConstantRange(C->getValue()->getValue(),
+ APInt(getTypeSizeInBits(C->getType()), 0));
// TODO: non-affine addrec
if (AddRec->isAffine()) {
const Type *Ty = AddRec->getType();
const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
- if (getTypeSizeInBits(MaxBECount->getType()) <= getTypeSizeInBits(Ty)) {
+ if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
+ getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
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.
- // TODO: This is very conservative.
- if (!(Step->isOne() &&
- isKnownPredicate(ICmpInst::ICMP_ULT, Start, End)) &&
- !(Step->isAllOnesValue() &&
- isKnownPredicate(ICmpInst::ICMP_UGT, Start, End)))
- return FullSet;
+ if (!AddRec->hasNoUnsignedWrap())
+ return ConservativeResult;
ConstantRange StartRange = getUnsignedRange(Start);
ConstantRange EndRange = getUnsignedRange(End);
APInt Max = APIntOps::umax(StartRange.getUnsignedMax(),
EndRange.getUnsignedMax());
if (Min.isMinValue() && Max.isMaxValue())
- return FullSet;
- return ConstantRange(Min, Max+1);
+ return ConservativeResult;
+ return ConservativeResult.intersectWith(ConstantRange(Min, Max+1));
}
}
+
+ return ConservativeResult;
}
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD);
if (Ones == ~Zeros + 1)
- return FullSet;
- return ConstantRange(Ones, ~Zeros + 1);
+ return ConservativeResult;
+ return ConservativeResult.intersectWith(ConstantRange(Ones, ~Zeros + 1));
}
- return FullSet;
+ return ConservativeResult;
}
/// getSignedRange - Determine the signed range for a particular SCEV.
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
return ConstantRange(C->getValue()->getValue());
+ unsigned BitWidth = getTypeSizeInBits(S->getType());
+ ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
+
+ // If the value has known zeros, the maximum signed value will have those
+ // known zeros as well.
+ uint32_t TZ = GetMinTrailingZeros(S);
+ if (TZ != 0)
+ ConservativeResult =
+ ConstantRange(APInt::getSignedMinValue(BitWidth),
+ APInt::getSignedMaxValue(BitWidth).ashr(TZ).shl(TZ) + 1);
+
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
ConstantRange X = getSignedRange(Add->getOperand(0));
for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i)
X = X.add(getSignedRange(Add->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
ConstantRange X = getSignedRange(Mul->getOperand(0));
for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i)
X = X.multiply(getSignedRange(Mul->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) {
ConstantRange X = getSignedRange(SMax->getOperand(0));
for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i)
X = X.smax(getSignedRange(SMax->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) {
ConstantRange X = getSignedRange(UMax->getOperand(0));
for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i)
X = X.umax(getSignedRange(UMax->getOperand(i)));
- return X;
+ return ConservativeResult.intersectWith(X);
}
if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
ConstantRange X = getSignedRange(UDiv->getLHS());
ConstantRange Y = getSignedRange(UDiv->getRHS());
- return X.udiv(Y);
+ return ConservativeResult.intersectWith(X.udiv(Y));
}
if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
ConstantRange X = getSignedRange(ZExt->getOperand());
- return X.zeroExtend(cast<IntegerType>(ZExt->getType())->getBitWidth());
+ return ConservativeResult.intersectWith(X.zeroExtend(BitWidth));
}
if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
ConstantRange X = getSignedRange(SExt->getOperand());
- return X.signExtend(cast<IntegerType>(SExt->getType())->getBitWidth());
+ return ConservativeResult.intersectWith(X.signExtend(BitWidth));
}
if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
ConstantRange X = getSignedRange(Trunc->getOperand());
- return X.truncate(cast<IntegerType>(Trunc->getType())->getBitWidth());
+ return ConservativeResult.intersectWith(X.truncate(BitWidth));
}
- ConstantRange FullSet(getTypeSizeInBits(S->getType()), true);
-
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
- const SCEV *T = getBackedgeTakenCount(AddRec->getLoop());
- const SCEVConstant *Trip = dyn_cast<SCEVConstant>(T);
- if (!Trip) return FullSet;
+ // If there's no signed wrap, and all the operands have the same sign or
+ // zero, the value won't ever change sign.
+ if (AddRec->hasNoSignedWrap()) {
+ bool AllNonNeg = true;
+ bool AllNonPos = true;
+ for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
+ if (!isKnownNonNegative(AddRec->getOperand(i))) AllNonNeg = false;
+ if (!isKnownNonPositive(AddRec->getOperand(i))) AllNonPos = false;
+ }
+ if (AllNonNeg)
+ ConservativeResult = ConservativeResult.intersectWith(
+ ConstantRange(APInt(BitWidth, 0),
+ APInt::getSignedMinValue(BitWidth)));
+ else if (AllNonPos)
+ ConservativeResult = ConservativeResult.intersectWith(
+ ConstantRange(APInt::getSignedMinValue(BitWidth),
+ APInt(BitWidth, 1)));
+ }
// TODO: non-affine addrec
if (AddRec->isAffine()) {
const Type *Ty = AddRec->getType();
const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
- if (getTypeSizeInBits(MaxBECount->getType()) <= getTypeSizeInBits(Ty)) {
+ if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
+ getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
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.
- // TODO: This is very conservative.
- if (!(Step->isOne() &&
- isKnownPredicate(ICmpInst::ICMP_SLT, Start, End)) &&
- !(Step->isAllOnesValue() &&
- isKnownPredicate(ICmpInst::ICMP_SGT, Start, End)))
- return FullSet;
+ if (!AddRec->hasNoSignedWrap())
+ return ConservativeResult;
ConstantRange StartRange = getSignedRange(Start);
ConstantRange EndRange = getSignedRange(End);
APInt Max = APIntOps::smax(StartRange.getSignedMax(),
EndRange.getSignedMax());
if (Min.isMinSignedValue() && Max.isMaxSignedValue())
- return FullSet;
- return ConstantRange(Min, Max+1);
+ return ConservativeResult;
+ return ConservativeResult.intersectWith(ConstantRange(Min, Max+1));
}
}
+
+ return ConservativeResult;
}
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
// For a SCEVUnknown, ask ValueTracking.
- unsigned BitWidth = getTypeSizeInBits(U->getType());
+ if (!U->getValue()->getType()->isInteger() && !TD)
+ return ConservativeResult;
unsigned NS = ComputeNumSignBits(U->getValue(), TD);
if (NS == 1)
- return FullSet;
- return
+ return ConservativeResult;
+ return ConservativeResult.intersectWith(
ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1),
- APInt::getSignedMaxValue(BitWidth).ashr(NS - 1)+1);
+ APInt::getSignedMaxValue(BitWidth).ashr(NS - 1)+1));
}
- return FullSet;
+ return ConservativeResult;
}
/// createSCEV - We know that there is no SCEV for the specified value.
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:
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:
case Instruction::Shl:
// 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();
+ uint32_t BitWidth = cast<IntegerType>(U->getType())->getBitWidth();
Constant *X = ConstantInt::get(getContext(),
APInt(BitWidth, 1).shl(SA->getLimitedValue(BitWidth)));
return getMulExpr(getSCEV(U->getOperand(0)), getSCEV(X));
case Instruction::LShr:
// 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();
+ uint32_t BitWidth = cast<IntegerType>(U->getType())->getBitWidth();
Constant *X = ConstantInt::get(getContext(),
APInt(BitWidth, 1).shl(SA->getLimitedValue(BitWidth)));
return getUDivExpr(getSCEV(U->getOperand(0)), getSCEV(X));
return getSCEV(U->getOperand(0));
break;
- // 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.
+ // It's tempting to handle inttoptr and ptrtoint as no-ops, however this can
+ // lead to pointer expressions which cannot safely be expanded to GEPs,
+ // because ScalarEvolution doesn't respect the GEP aliasing rules when
+ // simplifying integer expressions.
case Instruction::GetElementPtr:
- return createNodeForGEP(U);
+ return createNodeForGEP(cast<GEPOperator>(U));
case Instruction::PHI:
return createNodeForPHI(cast<PHINode>(U));
// 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);
- if (ItCount.Exact != getCouldNotCompute()) {
- assert(ItCount.Exact->isLoopInvariant(L) &&
- ItCount.Max->isLoopInvariant(L) &&
- "Computed trip count isn't loop invariant for loop!");
+ BackedgeTakenInfo BECount = ComputeBackedgeTakenCount(L);
+ if (BECount.Exact != getCouldNotCompute()) {
+ assert(BECount.Exact->isLoopInvariant(L) &&
+ BECount.Max->isLoopInvariant(L) &&
+ "Computed backedge-taken count isn't loop invariant for loop!");
++NumTripCountsComputed;
// Update the value in the map.
- Pair.first->second = ItCount;
+ Pair.first->second = BECount;
} else {
- if (ItCount.Max != getCouldNotCompute())
+ if (BECount.Max != getCouldNotCompute())
// Update the value in the map.
- Pair.first->second = ItCount;
+ Pair.first->second = BECount;
if (isa<PHINode>(L->getHeader()->begin()))
// Only count loops that have phi nodes as not being computable.
++NumTripCountsNotComputed;
// 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.
- if (ItCount.hasAnyInfo()) {
+ // information. This is similar to the code in forgetLoop, except that
+ // it handles SCEVUnknown PHI nodes specially.
+ if (BECount.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
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);
/// 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.
}
default:
#if 0
- errs() << "ComputeBackedgeTakenCount ";
+ dbgs() << "ComputeBackedgeTakenCount ";
if (ExitCond->getOperand(0)->getType()->isUnsigned())
- errs() << "[unsigned] ";
- errs() << *LHS << " "
+ dbgs() << "[unsigned] ";
+ dbgs() << *LHS << " "
<< Instruction::getOpcodeName(Instruction::ICmp)
<< " " << *RHS << "\n";
#endif
/// 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) {
// Form the GEP offset.
Indexes[VarIdxNum] = Val;
- Constant *Result = GetAddressedElementFromGlobal(getContext(), GV, Indexes);
+ Constant *Result = GetAddressedElementFromGlobal(GV, Indexes);
if (Result == 0) break; // Cannot compute!
// Evaluate the condition for this iteration.
if (!isa<ConstantInt>(Result)) break; // Couldn't decide for sure
if (cast<ConstantInt>(Result)->getValue().isMinValue()) {
#if 0
- errs() << "\n***\n*** Computed loop count " << *ItCst
+ dbgs() << "\n***\n*** Computed loop count " << *ItCst
<< "\n*** From global " << *GV << "*** BB: " << *L->getHeader()
<< "***\n";
#endif
// 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)
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();
}
// 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.
// Otherwise compute it.
const SCEV *C = computeSCEVAtScope(V, L);
- Pair.first->second = C;
+ ValuesAtScopes[V][L] = C;
return C;
}
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(),
- getContext());
+ Operands[0], Operands[1], TD);
else
C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size(),
- getContext());
+ &Operands[0], Operands.size(), TD);
return getSCEV(C);
}
}
// 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());
}
- if (isa<SCEVTargetDataConstant>(V))
- return V;
-
llvm_unreachable("Unknown SCEV type!");
return 0;
}
const SCEVConstant *R2 = dyn_cast<SCEVConstant>(Roots.second);
if (R1) {
#if 0
- errs() << "HFTZ: " << *V << " - sol#1: " << *R1
+ dbgs() << "HFTZ: " << *V << " - sol#1: " << *R1
<< " sol#2: " << *R2 << "\n";
#endif
// Pick the smallest positive root value.
/// CouldNotCompute if an intermediate computation overflows.
const SCEV *ScalarEvolution::getBECount(const SCEV *Start,
const SCEV *End,
- const SCEV *Step) {
+ const SCEV *Step,
+ bool NoWrap) {
+ assert(!isKnownNegative(Step) &&
+ "This code doesn't handle negative strides yet!");
+
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 = 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();
+ 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());
const SCEV *Step = AddRec->getStepRecurrence(*this);
- // TODO: handle non-constant strides.
- const SCEVConstant *CStep = dyn_cast<SCEVConstant>(Step);
- if (!CStep || CStep->isZero())
+ if (Step->isZero())
return getCouldNotCompute();
- if (CStep->isOne()) {
+ if (Step->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)) {
- // 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) {
- APInt Max = APInt::getSignedMaxValue(BitWidth);
- if ((Max - CStep->getValue()->getValue())
- .slt(CLimit->getValue()->getValue()))
- return getCouldNotCompute();
- } else {
- APInt Max = APInt::getMaxValue(BitWidth);
- if ((Max - CStep->getValue()->getValue())
- .ult(CLimit->getValue()->getValue()))
- return getCouldNotCompute();
- }
- } else
- // TODO: handle non-constant limit values below.
- return getCouldNotCompute();
+ } else if (isKnownPositive(Step)) {
+ // Test whether a positive iteration can step past the limit
+ // value and past the maximum value for its type in a single step.
+ // Note that it's not sufficient to check NoWrap here, because even
+ // though the value after a wrap is undefined, it's not undefined
+ // behavior, so if wrap does occur, the loop could either terminate or
+ // loop infinitely, but in either case, the loop is guaranteed to
+ // iterate at least until the iteration where the wrapping occurs.
+ const SCEV *One = getIntegerSCEV(1, Step->getType());
+ if (isSigned) {
+ APInt Max = APInt::getSignedMaxValue(BitWidth);
+ if ((Max - getSignedRange(getMinusSCEV(Step, One)).getSignedMax())
+ .slt(getSignedRange(RHS).getSignedMax()))
+ return getCouldNotCompute();
+ } else {
+ APInt Max = APInt::getMaxValue(BitWidth);
+ if ((Max - getUnsignedRange(getMinusSCEV(Step, One)).getUnsignedMax())
+ .ult(getUnsignedRange(RHS).getUnsignedMax()))
+ return getCouldNotCompute();
+ }
} else
- // TODO: handle negative strides below.
+ // TODO: Handle negative strides here and below.
return getCouldNotCompute();
// We know the LHS is of the form {n,+,s} and the RHS is some loop-invariant
getSignedRange(End).getSignedMax() :
getUnsignedRange(End).getUnsignedMax());
+ // If MaxEnd is within a step of the maximum integer value in its type,
+ // adjust it down to the minimum value which would produce the same effect.
+ // This allows the subsequent ceiling divison of (N+(step-1))/step to
+ // compute the correct value.
+ const SCEV *StepMinusOne = getMinusSCEV(Step,
+ getIntegerSCEV(1, Step->getType()));
+ MaxEnd = isSigned ?
+ getSMinExpr(MaxEnd,
+ getMinusSCEV(getConstant(APInt::getSignedMaxValue(BitWidth)),
+ StepMinusOne)) :
+ getUMinExpr(MaxEnd,
+ getMinusSCEV(getConstant(APInt::getMaxValue(BitWidth)),
+ StepMinusOne));
+
// 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);
}
bool ScalarEvolution::runOnFunction(Function &F) {
this->F = &F;
LI = &getAnalysis<LoopInfo>();
+ DT = &getAnalysis<DominatorTree>();
TD = getAnalysisIfAvailable<TargetData>();
return false;
}
void ScalarEvolution::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<LoopInfo>();
+ AU.addRequiredTransitive<DominatorTree>();
}
bool ScalarEvolution::hasLoopInvariantBackedgeTakenCount(const Loop *L) {
for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
PrintLoopInfo(OS, SE, *I);
- OS << "Loop " << L->getHeader()->getName() << ": ";
+ OS << "Loop ";
+ WriteAsOperand(OS, L->getHeader(), /*PrintType=*/false);
+ OS << ": ";
- SmallVector<BasicBlock*, 8> ExitBlocks;
+ SmallVector<BasicBlock *, 8> ExitBlocks;
L->getExitBlocks(ExitBlocks);
if (ExitBlocks.size() != 1)
OS << "<multiple exits> ";
OS << "Unpredictable backedge-taken count. ";
}
- OS << "\n";
- OS << "Loop " << L->getHeader()->getName() << ": ";
+ OS << "\n"
+ "Loop ";
+ WriteAsOperand(OS, L->getHeader(), /*PrintType=*/false);
+ OS << ": ";
if (!isa<SCEVCouldNotCompute>(SE->getMaxBackedgeTakenCount(L))) {
OS << "max backedge-taken count is " << *SE->getMaxBackedgeTakenCount(L);
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";
+ OS << "Classifying expressions for: ";
+ WriteAsOperand(OS, F, /*PrintType=*/false);
+ OS << "\n";
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
if (isSCEVable(I->getType())) {
OS << *I << '\n';
OS << "\n";
}
- OS << "Determining loop execution counts for: " << F->getName() << "\n";
+ OS << "Determining loop execution counts for: ";
+ WriteAsOperand(OS, F, /*PrintType=*/false);
+ OS << "\n";
for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
PrintLoopInfo(OS, &SE, *I);
}
projects / oota-llvm.git / blobdiff