// 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 SCEVHandle
-// 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/Analysis/ValueTracking.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Support/CFG.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"
-#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
-#include <ostream>
+#include "llvm/ADT/SmallPtrSet.h"
#include <algorithm>
-#include <cmath>
using namespace llvm;
STATISTIC(NumArrayLenItCounts,
static cl::opt<unsigned>
MaxBruteForceIterations("scalar-evolution-max-iterations", cl::ReallyHidden,
cl::desc("Maximum number of iterations SCEV will "
- "symbolically execute a constant derived loop"),
+ "symbolically execute a constant "
+ "derived loop"),
cl::init(100));
static RegisterPass<ScalarEvolution>
//===----------------------------------------------------------------------===//
// Implementation of the SCEV class.
//
+
SCEV::~SCEV() {}
-void SCEV::dump() const {
- print(errs());
- errs() << '\n';
-}
-void SCEV::print(std::ostream &o) const {
- raw_os_ostream OS(o);
- print(OS);
+void SCEV::dump() const {
+ print(dbgs());
+ dbgs() << '\n';
}
bool SCEV::isZero() const {
return false;
}
+bool SCEV::isOne() const {
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
+ return SC->getValue()->isOne();
+ return false;
+}
-SCEVCouldNotCompute::SCEVCouldNotCompute() : SCEV(scCouldNotCompute) {}
-SCEVCouldNotCompute::~SCEVCouldNotCompute() {}
+bool SCEV::isAllOnesValue() const {
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
+ return SC->getValue()->isAllOnesValue();
+ return false;
+}
+
+SCEVCouldNotCompute::SCEVCouldNotCompute() :
+ SCEV(FoldingSetNodeID(), scCouldNotCompute) {}
bool SCEVCouldNotCompute::isLoopInvariant(const Loop *L) const {
- assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return false;
}
const Type *SCEVCouldNotCompute::getType() const {
- assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return 0;
}
bool SCEVCouldNotCompute::hasComputableLoopEvolution(const Loop *L) const {
- assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return false;
}
-SCEVHandle SCEVCouldNotCompute::
-replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
- const SCEVHandle &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 {
return S->getSCEVType() == scCouldNotCompute;
}
-
-// SCEVConstants - Only allow the creation of one SCEVConstant for any
-// particular value. Don't use a SCEVHandle here, or else the object will
-// never be deleted!
-static ManagedStatic<std::map<ConstantInt*, SCEVConstant*> > SCEVConstants;
-
-
-SCEVConstant::~SCEVConstant() {
- SCEVConstants->erase(V);
+const SCEV *ScalarEvolution::getConstant(ConstantInt *V) {
+ FoldingSetNodeID ID;
+ ID.AddInteger(scConstant);
+ ID.AddPointer(V);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVConstant>();
+ new (S) SCEVConstant(ID, V);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
}
-SCEVHandle ScalarEvolution::getConstant(ConstantInt *V) {
- SCEVConstant *&R = (*SCEVConstants)[V];
- if (R == 0) R = new SCEVConstant(V);
- return R;
+const SCEV *ScalarEvolution::getConstant(const APInt& Val) {
+ return getConstant(ConstantInt::get(getContext(), Val));
}
-SCEVHandle ScalarEvolution::getConstant(const APInt& Val) {
- return getConstant(ConstantInt::get(Val));
+const SCEV *
+ScalarEvolution::getConstant(const Type *Ty, uint64_t V, bool isSigned) {
+ return getConstant(
+ ConstantInt::get(cast<IntegerType>(Ty), V, isSigned));
}
const Type *SCEVConstant::getType() const { return V->getType(); }
WriteAsOperand(OS, V, false);
}
-SCEVCastExpr::SCEVCastExpr(unsigned SCEVTy,
- const SCEVHandle &op, const Type *ty)
- : SCEV(SCEVTy), Op(op), Ty(ty) {}
-
-SCEVCastExpr::~SCEVCastExpr() {}
+SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeID &ID,
+ unsigned SCEVTy, const SCEV *op, const Type *ty)
+ : SCEV(ID, SCEVTy), Op(op), Ty(ty) {}
bool SCEVCastExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
return Op->dominates(BB, DT);
}
-// SCEVTruncates - Only allow the creation of one SCEVTruncateExpr for any
-// particular input. Don't use a SCEVHandle here, or else the object will
-// never be deleted!
-static ManagedStatic<std::map<std::pair<SCEV*, const Type*>,
- SCEVTruncateExpr*> > SCEVTruncates;
+bool SCEVCastExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ return Op->properlyDominates(BB, DT);
+}
-SCEVTruncateExpr::SCEVTruncateExpr(const SCEVHandle &op, const Type *ty)
- : SCEVCastExpr(scTruncate, op, ty) {
+SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeID &ID,
+ const SCEV *op, const Type *ty)
+ : SCEVCastExpr(ID, scTruncate, op, ty) {
assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate non-integer value!");
}
-SCEVTruncateExpr::~SCEVTruncateExpr() {
- SCEVTruncates->erase(std::make_pair(Op, Ty));
-}
-
void SCEVTruncateExpr::print(raw_ostream &OS) const {
- OS << "(truncate " << *Op << " to " << *Ty << ")";
+ OS << "(trunc " << *Op->getType() << " " << *Op << " to " << *Ty << ")";
}
-// SCEVZeroExtends - Only allow the creation of one SCEVZeroExtendExpr for any
-// particular input. Don't use a SCEVHandle here, or else the object will never
-// be deleted!
-static ManagedStatic<std::map<std::pair<SCEV*, const Type*>,
- SCEVZeroExtendExpr*> > SCEVZeroExtends;
-
-SCEVZeroExtendExpr::SCEVZeroExtendExpr(const SCEVHandle &op, const Type *ty)
- : SCEVCastExpr(scZeroExtend, op, ty) {
+SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeID &ID,
+ const SCEV *op, const Type *ty)
+ : SCEVCastExpr(ID, scZeroExtend, op, ty) {
assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot zero extend non-integer value!");
}
-SCEVZeroExtendExpr::~SCEVZeroExtendExpr() {
- SCEVZeroExtends->erase(std::make_pair(Op, Ty));
-}
-
void SCEVZeroExtendExpr::print(raw_ostream &OS) const {
- OS << "(zeroextend " << *Op << " to " << *Ty << ")";
+ OS << "(zext " << *Op->getType() << " " << *Op << " to " << *Ty << ")";
}
-// SCEVSignExtends - Only allow the creation of one SCEVSignExtendExpr for any
-// particular input. Don't use a SCEVHandle here, or else the object will never
-// be deleted!
-static ManagedStatic<std::map<std::pair<SCEV*, const Type*>,
- SCEVSignExtendExpr*> > SCEVSignExtends;
-
-SCEVSignExtendExpr::SCEVSignExtendExpr(const SCEVHandle &op, const Type *ty)
- : SCEVCastExpr(scSignExtend, op, ty) {
+SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeID &ID,
+ const SCEV *op, const Type *ty)
+ : SCEVCastExpr(ID, scSignExtend, op, ty) {
assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot sign extend non-integer value!");
}
-SCEVSignExtendExpr::~SCEVSignExtendExpr() {
- SCEVSignExtends->erase(std::make_pair(Op, Ty));
-}
-
void SCEVSignExtendExpr::print(raw_ostream &OS) const {
- OS << "(signextend " << *Op << " to " << *Ty << ")";
-}
-
-// SCEVCommExprs - Only allow the creation of one SCEVCommutativeExpr for any
-// particular input. Don't use a SCEVHandle here, or else the object will never
-// be deleted!
-static ManagedStatic<std::map<std::pair<unsigned, std::vector<SCEV*> >,
- SCEVCommutativeExpr*> > SCEVCommExprs;
-
-SCEVCommutativeExpr::~SCEVCommutativeExpr() {
- SCEVCommExprs->erase(std::make_pair(getSCEVType(),
- std::vector<SCEV*>(Operands.begin(),
- Operands.end())));
+ OS << "(sext " << *Op->getType() << " " << *Op << " to " << *Ty << ")";
}
void SCEVCommutativeExpr::print(raw_ostream &OS) const {
OS << ")";
}
-SCEVHandle SCEVCommutativeExpr::
-replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
- const SCEVHandle &Conc,
- ScalarEvolution &SE) const {
+bool SCEVNAryExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- SCEVHandle H =
- getOperand(i)->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H != getOperand(i)) {
- std::vector<SCEVHandle> 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
- assert(0 && "Unknown commutative expr!");
- }
+ if (!getOperand(i)->dominates(BB, DT))
+ return false;
}
- return this;
+ return true;
}
-bool SCEVCommutativeExpr::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;
}
-
-// SCEVUDivs - Only allow the creation of one SCEVUDivExpr for any particular
-// input. Don't use a SCEVHandle here, or else the object will never be
-// deleted!
-static ManagedStatic<std::map<std::pair<SCEV*, SCEV*>,
- SCEVUDivExpr*> > SCEVUDivs;
-
-SCEVUDivExpr::~SCEVUDivExpr() {
- SCEVUDivs->erase(std::make_pair(LHS, RHS));
-}
-
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 << ")";
}
const Type *SCEVUDivExpr::getType() const {
- return LHS->getType();
+ // In most cases the types of LHS and RHS will be the same, but in some
+ // crazy cases one or the other may be a pointer. ScalarEvolution doesn't
+ // depend on the type for correctness, but handling types carefully can
+ // avoid extra casts in the SCEVExpander. The LHS is more likely to be
+ // a pointer type than the RHS, so use the RHS' type here.
+ return RHS->getType();
}
-// SCEVAddRecExprs - Only allow the creation of one SCEVAddRecExpr for any
-// particular input. Don't use a SCEVHandle here, or else the object will never
-// be deleted!
-static ManagedStatic<std::map<std::pair<const Loop *, std::vector<SCEV*> >,
- SCEVAddRecExpr*> > SCEVAddRecExprs;
+bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
+ // Add recurrences are never invariant in the function-body (null loop).
+ if (!QueryLoop)
+ return false;
-SCEVAddRecExpr::~SCEVAddRecExpr() {
- SCEVAddRecExprs->erase(std::make_pair(L,
- std::vector<SCEV*>(Operands.begin(),
- Operands.end())));
-}
+ // This recurrence is variant w.r.t. QueryLoop if QueryLoop contains L.
+ if (QueryLoop->contains(L))
+ return false;
-bool SCEVAddRecExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- if (!getOperand(i)->dominates(BB, DT))
+ // This recurrence is variant w.r.t. QueryLoop if any of its operands
+ // are variant.
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+ if (!getOperand(i)->isLoopInvariant(QueryLoop))
return false;
- }
- return true;
-}
-
-
-SCEVHandle SCEVAddRecExpr::
-replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
- const SCEVHandle &Conc,
- ScalarEvolution &SE) const {
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- SCEVHandle H =
- getOperand(i)->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H != getOperand(i)) {
- std::vector<SCEVHandle> 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 {
- // This recurrence is invariant w.r.t to QueryLoop iff QueryLoop doesn't
- // contain L and if the start is invariant.
- return !QueryLoop->contains(L->getHeader()) &&
- getOperand(0)->isLoopInvariant(QueryLoop);
+ // Otherwise it's loop-invariant.
+ return true;
}
-
void SCEVAddRecExpr::print(raw_ostream &OS) const {
OS << "{" << *Operands[0];
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
OS << ",+," << *Operands[i];
- OS << "}<" << L->getHeader()->getName() + ">";
+ OS << "}<";
+ WriteAsOperand(OS, L->getHeader(), /*PrintType=*/false);
+ OS << ">";
}
-// SCEVUnknowns - Only allow the creation of one SCEVUnknown for any particular
-// value. Don't use a SCEVHandle here, or else the object will never be
-// deleted!
-static ManagedStatic<std::map<Value*, SCEVUnknown*> > SCEVUnknowns;
-
-SCEVUnknown::~SCEVUnknown() { SCEVUnknowns->erase(V); }
-
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->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 {
- if (isa<PointerType>(V->getType()))
- OS << "(ptrtoint " << *V->getType() << " ";
+ 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);
- if (isa<PointerType>(V->getType()))
- OS << " to iPTR)";
}
//===----------------------------------------------------------------------===//
// 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.
- struct VISIBILITY_HIDDEN SCEVComplexityCompare {
+ class SCEVComplexityCompare {
+ LoopInfo *LI;
+ public:
+ explicit SCEVComplexityCompare(LoopInfo *li) : LI(li) {}
+
bool operator()(const SCEV *LHS, const SCEV *RHS) const {
- return LHS->getSCEVType() < RHS->getSCEVType();
+ // 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();
+
+ // Aside from the getSCEVType() ordering, the particular ordering
+ // isn't very important except that it's beneficial to be consistent,
+ // so that (a + b) and (b + a) don't end up as different expressions.
+
+ // Sort SCEVUnknown values with some loose heuristics. TODO: This is
+ // not as complete as it could be.
+ if (const SCEVUnknown *LU = dyn_cast<SCEVUnknown>(LHS)) {
+ const SCEVUnknown *RU = cast<SCEVUnknown>(RHS);
+
+ // Order pointer values after integer values. This helps SCEVExpander
+ // form GEPs.
+ if (isa<PointerType>(LU->getType()) && !isa<PointerType>(RU->getType()))
+ return false;
+ if (isa<PointerType>(RU->getType()) && !isa<PointerType>(LU->getType()))
+ return true;
+
+ // Compare getValueID values.
+ if (LU->getValue()->getValueID() != RU->getValue()->getValueID())
+ return LU->getValue()->getValueID() < RU->getValue()->getValueID();
+
+ // Sort arguments by their position.
+ if (const Argument *LA = dyn_cast<Argument>(LU->getValue())) {
+ const Argument *RA = cast<Argument>(RU->getValue());
+ return LA->getArgNo() < RA->getArgNo();
+ }
+
+ // For instructions, compare their loop depth, and their opcode.
+ // This is pretty loose.
+ if (Instruction *LV = dyn_cast<Instruction>(LU->getValue())) {
+ Instruction *RV = cast<Instruction>(RU->getValue());
+
+ // Compare loop depths.
+ if (LI->getLoopDepth(LV->getParent()) !=
+ LI->getLoopDepth(RV->getParent()))
+ return LI->getLoopDepth(LV->getParent()) <
+ LI->getLoopDepth(RV->getParent());
+
+ // Compare opcodes.
+ if (LV->getOpcode() != RV->getOpcode())
+ return LV->getOpcode() < RV->getOpcode();
+
+ // Compare the number of operands.
+ if (LV->getNumOperands() != RV->getNumOperands())
+ return LV->getNumOperands() < RV->getNumOperands();
+ }
+
+ return false;
+ }
+
+ // Compare constant values.
+ if (const SCEVConstant *LC = dyn_cast<SCEVConstant>(LHS)) {
+ const SCEVConstant *RC = cast<SCEVConstant>(RHS);
+ if (LC->getValue()->getBitWidth() != RC->getValue()->getBitWidth())
+ return LC->getValue()->getBitWidth() < RC->getValue()->getBitWidth();
+ return LC->getValue()->getValue().ult(RC->getValue()->getValue());
+ }
+
+ // Compare addrec loop depths.
+ if (const SCEVAddRecExpr *LA = dyn_cast<SCEVAddRecExpr>(LHS)) {
+ const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS);
+ if (LA->getLoop()->getLoopDepth() != RA->getLoop()->getLoopDepth())
+ return LA->getLoop()->getLoopDepth() < RA->getLoop()->getLoopDepth();
+ }
+
+ // Lexicographically compare n-ary expressions.
+ if (const SCEVNAryExpr *LC = dyn_cast<SCEVNAryExpr>(LHS)) {
+ const SCEVNAryExpr *RC = cast<SCEVNAryExpr>(RHS);
+ for (unsigned i = 0, e = LC->getNumOperands(); i != e; ++i) {
+ if (i >= RC->getNumOperands())
+ return false;
+ if (operator()(LC->getOperand(i), RC->getOperand(i)))
+ return true;
+ if (operator()(RC->getOperand(i), LC->getOperand(i)))
+ return false;
+ }
+ return LC->getNumOperands() < RC->getNumOperands();
+ }
+
+ // Lexicographically compare udiv expressions.
+ if (const SCEVUDivExpr *LC = dyn_cast<SCEVUDivExpr>(LHS)) {
+ const SCEVUDivExpr *RC = cast<SCEVUDivExpr>(RHS);
+ if (operator()(LC->getLHS(), RC->getLHS()))
+ return true;
+ if (operator()(RC->getLHS(), LC->getLHS()))
+ return false;
+ if (operator()(LC->getRHS(), RC->getRHS()))
+ return true;
+ if (operator()(RC->getRHS(), LC->getRHS()))
+ return false;
+ return false;
+ }
+
+ // Compare cast expressions by operand.
+ if (const SCEVCastExpr *LC = dyn_cast<SCEVCastExpr>(LHS)) {
+ const SCEVCastExpr *RC = cast<SCEVCastExpr>(RHS);
+ return operator()(LC->getOperand(), RC->getOperand());
+ }
+
+ llvm_unreachable("Unknown SCEV kind!");
+ return false;
}
};
}
/// this to depend on where the addresses of various SCEV objects happened to
/// land in memory.
///
-static void GroupByComplexity(std::vector<SCEVHandle> &Ops) {
+static void GroupByComplexity(SmallVectorImpl<const SCEV *> &Ops,
+ LoopInfo *LI) {
if (Ops.size() < 2) return; // Noop
if (Ops.size() == 2) {
// This is the common case, which also happens to be trivially simple.
// Special case it.
- if (SCEVComplexityCompare()(Ops[1], Ops[0]))
+ if (SCEVComplexityCompare(LI)(Ops[1], Ops[0]))
std::swap(Ops[0], Ops[1]);
return;
}
// Do the rough sort by complexity.
- std::sort(Ops.begin(), Ops.end(), SCEVComplexityCompare());
+ std::stable_sort(Ops.begin(), Ops.end(), SCEVComplexityCompare(LI));
// Now that we are sorted by complexity, group elements of the same
// complexity. Note that this is, at worst, N^2, but the vector is likely to
// be extremely short in practice. Note that we take this approach because we
// do not want to depend on the addresses of the objects we are grouping.
for (unsigned i = 0, e = Ops.size(); i != e-2; ++i) {
- SCEV *S = Ops[i];
+ const SCEV *S = Ops[i];
unsigned Complexity = S->getSCEVType();
// If there are any objects of the same complexity and same value as this
//===----------------------------------------------------------------------===//
/// BinomialCoefficient - Compute BC(It, K). The result has width W.
-// Assume, K > 0.
-static SCEVHandle BinomialCoefficient(SCEVHandle It, unsigned K,
- ScalarEvolution &SE,
- const Type* ResultTy) {
+/// Assume, K > 0.
+static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K,
+ ScalarEvolution &SE,
+ const Type* ResultTy) {
// Handle the simplest case efficiently.
if (K == 1)
return SE.getTruncateOrZeroExtend(It, ResultTy);
// safe in modular arithmetic.
//
// However, this code doesn't use exactly that formula; the formula it uses
- // is something like the following, where T is the number of factors of 2 in
+ // is something like the following, where T is the number of factors of 2 in
// K! (i.e. trailing zeros in the binary representation of K!), and ^ is
// exponentiation:
//
// arithmetic. To do exact division in modular arithmetic, all we have
// to do is multiply by the inverse. Therefore, this step can be done at
// width W.
- //
+ //
// The next issue is how to safely do the division by 2^T. The way this
// is done is by doing the multiplication step at a width of at least W + T
// bits. This way, the bottom W+T bits of the product are accurate. Then,
MultiplyFactor = MultiplyFactor.trunc(W);
// Calculate the product, at width T+W
- const IntegerType *CalculationTy = IntegerType::get(CalculationBits);
- SCEVHandle Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy);
+ const IntegerType *CalculationTy = IntegerType::get(SE.getContext(),
+ CalculationBits);
+ const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy);
for (unsigned i = 1; i != K; ++i) {
- SCEVHandle S = SE.getMinusSCEV(It, SE.getIntegerSCEV(i, It->getType()));
+ const SCEV *S = SE.getMinusSCEV(It, SE.getIntegerSCEV(i, It->getType()));
Dividend = SE.getMulExpr(Dividend,
SE.getTruncateOrZeroExtend(S, CalculationTy));
}
// Divide by 2^T
- SCEVHandle DivResult = SE.getUDivExpr(Dividend, SE.getConstant(DivFactor));
+ const SCEV *DivResult = SE.getUDivExpr(Dividend, SE.getConstant(DivFactor));
// Truncate the result, and divide by K! / 2^T.
///
/// where BC(It, k) stands for binomial coefficient.
///
-SCEVHandle SCEVAddRecExpr::evaluateAtIteration(SCEVHandle It,
- ScalarEvolution &SE) const {
- SCEVHandle Result = getStart();
+const SCEV *SCEVAddRecExpr::evaluateAtIteration(const SCEV *It,
+ 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
// multiplication is performed _after_ the evaluation of the binomial
// coefficient.
- SCEVHandle Coeff = BinomialCoefficient(It, i, SE, getType());
+ const SCEV *Coeff = BinomialCoefficient(It, i, SE, getType());
if (isa<SCEVCouldNotCompute>(Coeff))
return Coeff;
// SCEV Expression folder implementations
//===----------------------------------------------------------------------===//
-SCEVHandle ScalarEvolution::getTruncateExpr(const SCEVHandle &Op, const Type *Ty) {
+const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op,
+ const Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) &&
"This is not a truncating conversion!");
+ assert(isSCEVable(Ty) &&
+ "This is not a conversion to a SCEVable type!");
+ Ty = getEffectiveSCEVType(Ty);
+
+ FoldingSetNodeID ID;
+ ID.AddInteger(scTruncate);
+ ID.AddPointer(Op);
+ ID.AddPointer(Ty);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
- return getUnknown(
- ConstantExpr::getTrunc(SC->getValue(), Ty));
+ // Fold if the operand is constant.
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
+ return getConstant(
+ cast<ConstantInt>(ConstantExpr::getTrunc(SC->getValue(), Ty)));
// trunc(trunc(x)) --> trunc(x)
- if (SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op))
+ if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op))
return getTruncateExpr(ST->getOperand(), Ty);
// trunc(sext(x)) --> sext(x) if widening or trunc(x) if narrowing
- if (SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
+ if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
return getTruncateOrSignExtend(SS->getOperand(), Ty);
// trunc(zext(x)) --> zext(x) if widening or trunc(x) if narrowing
- if (SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
+ if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
return getTruncateOrZeroExtend(SZ->getOperand(), Ty);
- // If the input value is a chrec scev made out of constants, truncate
- // all of the constants.
- if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
- std::vector<SCEVHandle> Operands;
+ // If the input value is a chrec scev, truncate the chrec's operands.
+ if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
+ SmallVector<const SCEV *, 4> Operands;
for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
- // FIXME: This should allow truncation of other expression types!
- if (isa<SCEVConstant>(AddRec->getOperand(i)))
- Operands.push_back(getTruncateExpr(AddRec->getOperand(i), Ty));
- else
- break;
- if (Operands.size() == AddRec->getNumOperands())
- return getAddRecExpr(Operands, AddRec->getLoop());
+ Operands.push_back(getTruncateExpr(AddRec->getOperand(i), Ty));
+ return getAddRecExpr(Operands, AddRec->getLoop());
}
- SCEVTruncateExpr *&Result = (*SCEVTruncates)[std::make_pair(Op, Ty)];
- if (Result == 0) Result = new SCEVTruncateExpr(Op, Ty);
- return Result;
+ // The cast wasn't folded; create an explicit cast node.
+ // Recompute the insert position, as it may have been invalidated.
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVTruncateExpr>();
+ new (S) SCEVTruncateExpr(ID, Op, Ty);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
}
-SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op,
- const Type *Ty) {
+const SCEV *ScalarEvolution::getZeroExtendExpr(const SCEV *Op,
+ const Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
"This is not an extending conversion!");
+ assert(isSCEVable(Ty) &&
+ "This is not a conversion to a SCEVable type!");
+ Ty = getEffectiveSCEVType(Ty);
- if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
+ // Fold if the operand is constant.
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
const Type *IntTy = getEffectiveSCEVType(Ty);
Constant *C = ConstantExpr::getZExt(SC->getValue(), IntTy);
if (IntTy != Ty) C = ConstantExpr::getIntToPtr(C, Ty);
- return getUnknown(C);
+ return getConstant(cast<ConstantInt>(C));
}
// zext(zext(x)) --> zext(x)
- if (SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
+ if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
return getZeroExtendExpr(SZ->getOperand(), Ty);
+ // Before doing any expensive analysis, check to see if we've already
+ // computed a SCEV for this Op and Ty.
+ FoldingSetNodeID ID;
+ ID.AddInteger(scZeroExtend);
+ ID.AddPointer(Op);
+ ID.AddPointer(Ty);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+
// If the input value is a chrec scev, and we can prove that the value
// did not overflow the old, smaller, value, we can zero extend all of the
// operands (often constants). This allows analysis of something like
// this: for (unsigned char X = 0; X < 100; ++X) { int Y = X; }
- if (SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
if (AR->isAffine()) {
+ const SCEV *Start = AR->getStart();
+ const SCEV *Step = AR->getStepRecurrence(*this);
+ 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
// in infinite recursion. In the later case, the analysis code will
// cope with a conservative value, and it will take care to purge
// that value once it has finished.
- SCEVHandle BECount = getBackedgeTakenCount(AR->getLoop());
- if (!isa<SCEVCouldNotCompute>(BECount)) {
+ const SCEV *MaxBECount = getMaxBackedgeTakenCount(L);
+ if (!isa<SCEVCouldNotCompute>(MaxBECount)) {
// Manually compute the final value for AR, checking for
- // overflow at each step.
- SCEVHandle Start = AR->getStart();
- SCEVHandle Step = AR->getStepRecurrence(*this);
+ // overflow.
// Check whether the backedge-taken count can be losslessly casted to
// the addrec's type. The count is always unsigned.
- SCEVHandle CastedBECount =
- getTruncateOrZeroExtend(BECount, Start->getType());
- if (BECount ==
- getTruncateOrZeroExtend(CastedBECount, BECount->getType())) {
- const Type *WideTy =
- IntegerType::get(getTypeSizeInBits(Start->getType()) * 2);
- SCEVHandle ZMul =
- getMulExpr(CastedBECount,
+ const SCEV *CastedMaxBECount =
+ getTruncateOrZeroExtend(MaxBECount, Start->getType());
+ const SCEV *RecastedMaxBECount =
+ getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
+ if (MaxBECount == RecastedMaxBECount) {
+ const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
+ // Check whether Start+Step*MaxBECount has no unsigned overflow.
+ const SCEV *ZMul =
+ getMulExpr(CastedMaxBECount,
getTruncateOrZeroExtend(Step, Start->getType()));
- // Check whether Start+Step*BECount has no unsigned overflow.
- if (getZeroExtendExpr(ZMul, WideTy) ==
- getMulExpr(getZeroExtendExpr(CastedBECount, WideTy),
- getZeroExtendExpr(Step, WideTy))) {
- SCEVHandle Add = getAddExpr(Start, ZMul);
- if (getZeroExtendExpr(Add, WideTy) ==
- getAddExpr(getZeroExtendExpr(Start, WideTy),
- getZeroExtendExpr(ZMul, WideTy)))
- // Return the expression with the addrec on the outside.
- return getAddRecExpr(getZeroExtendExpr(Start, Ty),
- getZeroExtendExpr(Step, Ty),
- AR->getLoop());
- }
+ const SCEV *Add = getAddExpr(Start, ZMul);
+ const SCEV *OperandExtendedAdd =
+ getAddExpr(getZeroExtendExpr(Start, WideTy),
+ getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+ getZeroExtendExpr(Step, WideTy)));
+ if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getZeroExtendExpr(Start, Ty),
+ getZeroExtendExpr(Step, Ty),
+ L);
// Similar to above, only this time treat the step value as signed.
// This covers loops that count down.
- SCEVHandle SMul =
- getMulExpr(CastedBECount,
+ const SCEV *SMul =
+ getMulExpr(CastedMaxBECount,
getTruncateOrSignExtend(Step, Start->getType()));
- // Check whether Start+Step*BECount has no unsigned overflow.
- if (getSignExtendExpr(SMul, WideTy) ==
- getMulExpr(getZeroExtendExpr(CastedBECount, WideTy),
- getSignExtendExpr(Step, WideTy))) {
- SCEVHandle Add = getAddExpr(Start, SMul);
- if (getZeroExtendExpr(Add, WideTy) ==
- getAddExpr(getZeroExtendExpr(Start, WideTy),
- getSignExtendExpr(SMul, WideTy)))
- // Return the expression with the addrec on the outside.
- return getAddRecExpr(getZeroExtendExpr(Start, Ty),
- getSignExtendExpr(Step, Ty),
- AR->getLoop());
- }
+ Add = getAddExpr(Start, SMul);
+ OperandExtendedAdd =
+ getAddExpr(getZeroExtendExpr(Start, WideTy),
+ getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+ getSignExtendExpr(Step, WideTy)));
+ if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getZeroExtendExpr(Start, Ty),
+ getSignExtendExpr(Step, Ty),
+ L);
+ }
+
+ // If the backedge is guarded by a comparison with the pre-inc value
+ // the addrec is safe. Also, if the entry is guarded by a comparison
+ // with the start value and the backedge is guarded by a comparison
+ // with the post-inc value, the addrec is safe.
+ if (isKnownPositive(Step)) {
+ const SCEV *N = getConstant(APInt::getMinValue(BitWidth) -
+ getUnsignedRange(Step).getUnsignedMax());
+ if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT, AR, N) ||
+ (isLoopGuardedByCond(L, ICmpInst::ICMP_ULT, Start, N) &&
+ isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT,
+ AR->getPostIncExpr(*this), N)))
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getZeroExtendExpr(Start, Ty),
+ getZeroExtendExpr(Step, Ty),
+ L);
+ } else if (isKnownNegative(Step)) {
+ const SCEV *N = getConstant(APInt::getMaxValue(BitWidth) -
+ getSignedRange(Step).getSignedMin());
+ if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT, AR, N) &&
+ (isLoopGuardedByCond(L, ICmpInst::ICMP_UGT, Start, N) ||
+ isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT,
+ AR->getPostIncExpr(*this), N)))
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getZeroExtendExpr(Start, Ty),
+ getSignExtendExpr(Step, Ty),
+ L);
}
}
}
- SCEVZeroExtendExpr *&Result = (*SCEVZeroExtends)[std::make_pair(Op, Ty)];
- if (Result == 0) Result = new SCEVZeroExtendExpr(Op, Ty);
- return Result;
+ // The cast wasn't folded; create an explicit cast node.
+ // Recompute the insert position, as it may have been invalidated.
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVZeroExtendExpr>();
+ new (S) SCEVZeroExtendExpr(ID, Op, Ty);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
}
-SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op,
- const Type *Ty) {
+const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op,
+ const Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
"This is not an extending conversion!");
+ assert(isSCEVable(Ty) &&
+ "This is not a conversion to a SCEVable type!");
+ Ty = getEffectiveSCEVType(Ty);
- if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
+ // Fold if the operand is constant.
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
const Type *IntTy = getEffectiveSCEVType(Ty);
Constant *C = ConstantExpr::getSExt(SC->getValue(), IntTy);
if (IntTy != Ty) C = ConstantExpr::getIntToPtr(C, Ty);
- return getUnknown(C);
+ return getConstant(cast<ConstantInt>(C));
}
// sext(sext(x)) --> sext(x)
- if (SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
+ if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
return getSignExtendExpr(SS->getOperand(), Ty);
+ // Before doing any expensive analysis, check to see if we've already
+ // computed a SCEV for this Op and Ty.
+ FoldingSetNodeID ID;
+ ID.AddInteger(scSignExtend);
+ ID.AddPointer(Op);
+ ID.AddPointer(Ty);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+
// If the input value is a chrec scev, and we can prove that the value
// did not overflow the old, smaller, value, we can sign extend all of the
// operands (often constants). This allows analysis of something like
// this: for (signed char X = 0; X < 100; ++X) { int Y = X; }
- if (SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
if (AR->isAffine()) {
+ const SCEV *Start = AR->getStart();
+ const SCEV *Step = AR->getStepRecurrence(*this);
+ 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
// in infinite recursion. In the later case, the analysis code will
// cope with a conservative value, and it will take care to purge
// that value once it has finished.
- SCEVHandle BECount = getBackedgeTakenCount(AR->getLoop());
- if (!isa<SCEVCouldNotCompute>(BECount)) {
+ const SCEV *MaxBECount = getMaxBackedgeTakenCount(L);
+ if (!isa<SCEVCouldNotCompute>(MaxBECount)) {
// Manually compute the final value for AR, checking for
- // overflow at each step.
- SCEVHandle Start = AR->getStart();
- SCEVHandle Step = AR->getStepRecurrence(*this);
+ // overflow.
// Check whether the backedge-taken count can be losslessly casted to
- // the addrec's type. The count needs to be the same whether sign
- // extended or zero extended.
- SCEVHandle CastedBECount =
- getTruncateOrZeroExtend(BECount, Start->getType());
- if (BECount ==
- getTruncateOrZeroExtend(CastedBECount, BECount->getType()) &&
- BECount ==
- getTruncateOrSignExtend(CastedBECount, BECount->getType())) {
- const Type *WideTy =
- IntegerType::get(getTypeSizeInBits(Start->getType()) * 2);
- SCEVHandle SMul =
- getMulExpr(CastedBECount,
+ // the addrec's type. The count is always unsigned.
+ const SCEV *CastedMaxBECount =
+ getTruncateOrZeroExtend(MaxBECount, Start->getType());
+ const SCEV *RecastedMaxBECount =
+ getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
+ if (MaxBECount == RecastedMaxBECount) {
+ const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
+ // Check whether Start+Step*MaxBECount has no signed overflow.
+ const SCEV *SMul =
+ getMulExpr(CastedMaxBECount,
getTruncateOrSignExtend(Step, Start->getType()));
- // Check whether Start+Step*BECount has no signed overflow.
- if (getSignExtendExpr(SMul, WideTy) ==
- getMulExpr(getSignExtendExpr(CastedBECount, WideTy),
- getSignExtendExpr(Step, WideTy))) {
- SCEVHandle Add = getAddExpr(Start, SMul);
- if (getSignExtendExpr(Add, WideTy) ==
- getAddExpr(getSignExtendExpr(Start, WideTy),
- getSignExtendExpr(SMul, WideTy)))
- // Return the expression with the addrec on the outside.
- return getAddRecExpr(getSignExtendExpr(Start, Ty),
- getSignExtendExpr(Step, Ty),
- AR->getLoop());
- }
+ const SCEV *Add = getAddExpr(Start, SMul);
+ const SCEV *OperandExtendedAdd =
+ getAddExpr(getSignExtendExpr(Start, WideTy),
+ getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+ getSignExtendExpr(Step, WideTy)));
+ if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ // Return the expression with the addrec on the outside.
+ 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
+ // the addrec is safe. Also, if the entry is guarded by a comparison
+ // with the start value and the backedge is guarded by a comparison
+ // with the post-inc value, the addrec is safe.
+ if (isKnownPositive(Step)) {
+ const SCEV *N = getConstant(APInt::getSignedMinValue(BitWidth) -
+ getSignedRange(Step).getSignedMax());
+ if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SLT, AR, N) ||
+ (isLoopGuardedByCond(L, ICmpInst::ICMP_SLT, Start, N) &&
+ isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SLT,
+ AR->getPostIncExpr(*this), N)))
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ getSignExtendExpr(Step, Ty),
+ L);
+ } else if (isKnownNegative(Step)) {
+ const SCEV *N = getConstant(APInt::getSignedMaxValue(BitWidth) -
+ getSignedRange(Step).getSignedMin());
+ if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SGT, AR, N) ||
+ (isLoopGuardedByCond(L, ICmpInst::ICMP_SGT, Start, N) &&
+ isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SGT,
+ AR->getPostIncExpr(*this), N)))
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ getSignExtendExpr(Step, Ty),
+ L);
}
}
}
- SCEVSignExtendExpr *&Result = (*SCEVSignExtends)[std::make_pair(Op, Ty)];
- if (Result == 0) Result = new SCEVSignExtendExpr(Op, Ty);
- return Result;
+ // The cast wasn't folded; create an explicit cast node.
+ // Recompute the insert position, as it may have been invalidated.
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVSignExtendExpr>();
+ new (S) SCEVSignExtendExpr(ID, Op, Ty);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
+}
+
+/// getAnyExtendExpr - Return a SCEV for the given operand extended with
+/// unspecified bits out to the given type.
+///
+const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op,
+ const Type *Ty) {
+ assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
+ "This is not an extending conversion!");
+ assert(isSCEVable(Ty) &&
+ "This is not a conversion to a SCEVable type!");
+ Ty = getEffectiveSCEVType(Ty);
+
+ // Sign-extend negative constants.
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
+ if (SC->getValue()->getValue().isNegative())
+ return getSignExtendExpr(Op, Ty);
+
+ // Peel off a truncate cast.
+ if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Op)) {
+ const SCEV *NewOp = T->getOperand();
+ if (getTypeSizeInBits(NewOp->getType()) < getTypeSizeInBits(Ty))
+ return getAnyExtendExpr(NewOp, Ty);
+ return getTruncateOrNoop(NewOp, Ty);
+ }
+
+ // Next try a zext cast. If the cast is folded, use it.
+ const SCEV *ZExt = getZeroExtendExpr(Op, Ty);
+ if (!isa<SCEVZeroExtendExpr>(ZExt))
+ return ZExt;
+
+ // Next try a sext cast. If the cast is folded, use it.
+ const SCEV *SExt = getSignExtendExpr(Op, Ty);
+ 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;
+
+ // Absent any other information, use the zext cast value.
+ return ZExt;
+}
+
+/// CollectAddOperandsWithScales - Process the given Ops list, which is
+/// a list of operands to be added under the given scale, update the given
+/// map. This is a helper function for getAddRecExpr. As an example of
+/// what it does, given a sequence of operands that would form an add
+/// expression like this:
+///
+/// m + n + 13 + (A * (o + p + (B * q + m + 29))) + r + (-1 * r)
+///
+/// where A and B are constants, update the map with these values:
+///
+/// (m, 1+A*B), (n, 1), (o, A), (p, A), (q, A*B), (r, 0)
+///
+/// and add 13 + A*B*29 to AccumulatedConstant.
+/// This will allow getAddRecExpr to produce this:
+///
+/// 13+A*B*29 + n + (m * (1+A*B)) + ((o + p) * A) + (q * A*B)
+///
+/// This form often exposes folding opportunities that are hidden in
+/// the original operand list.
+///
+/// Return true iff it appears that any interesting folding opportunities
+/// may be exposed. This helps getAddRecExpr short-circuit extra work in
+/// the common case where no interesting opportunities are present, and
+/// is also used as a check to avoid infinite recursion.
+///
+static bool
+CollectAddOperandsWithScales(DenseMap<const SCEV *, APInt> &M,
+ SmallVector<const SCEV *, 8> &NewOps,
+ APInt &AccumulatedConstant,
+ const SmallVectorImpl<const SCEV *> &Ops,
+ const APInt &Scale,
+ ScalarEvolution &SE) {
+ bool Interesting = false;
+
+ // Iterate over the add operands.
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
+ const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[i]);
+ if (Mul && isa<SCEVConstant>(Mul->getOperand(0))) {
+ APInt NewScale =
+ Scale * cast<SCEVConstant>(Mul->getOperand(0))->getValue()->getValue();
+ if (Mul->getNumOperands() == 2 && isa<SCEVAddExpr>(Mul->getOperand(1))) {
+ // A multiplication of a constant with another add; recurse.
+ Interesting |=
+ CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant,
+ cast<SCEVAddExpr>(Mul->getOperand(1))
+ ->getOperands(),
+ NewScale, SE);
+ } else {
+ // A multiplication of a constant with some other value. Update
+ // the map.
+ SmallVector<const SCEV *, 4> MulOps(Mul->op_begin()+1, Mul->op_end());
+ const SCEV *Key = SE.getMulExpr(MulOps);
+ std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair =
+ M.insert(std::make_pair(Key, NewScale));
+ if (Pair.second) {
+ NewOps.push_back(Pair.first->first);
+ } else {
+ Pair.first->second += NewScale;
+ // The map already had an entry for this value, which may indicate
+ // a folding opportunity.
+ Interesting = true;
+ }
+ }
+ } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
+ // Pull a buried constant out to the outside.
+ if (Scale != 1 || AccumulatedConstant != 0 || C->isZero())
+ Interesting = true;
+ AccumulatedConstant += Scale * C->getValue()->getValue();
+ } else {
+ // An ordinary operand. Update the map.
+ std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair =
+ M.insert(std::make_pair(Ops[i], Scale));
+ if (Pair.second) {
+ NewOps.push_back(Pair.first->first);
+ } else {
+ Pair.first->second += Scale;
+ // The map already had an entry for this value, which may indicate
+ // a folding opportunity.
+ Interesting = true;
+ }
+ }
+ }
+
+ return Interesting;
+}
+
+namespace {
+ struct APIntCompare {
+ bool operator()(const APInt &LHS, const APInt &RHS) const {
+ return LHS.ult(RHS);
+ }
+ };
}
-// get - Get a canonical add expression, or something simpler if possible.
-SCEVHandle ScalarEvolution::getAddExpr(std::vector<SCEVHandle> &Ops) {
+/// getAddExpr - Get a canonical add expression, or something simpler if
+/// possible.
+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
+ for (unsigned i = 1, e = Ops.size(); i != e; ++i)
+ assert(getEffectiveSCEVType(Ops[i]->getType()) ==
+ getEffectiveSCEVType(Ops[0]->getType()) &&
+ "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);
+ GroupByComplexity(Ops, LI);
// If there are any constants, fold them together.
unsigned Idx = 0;
- if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
+ if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
++Idx;
assert(Idx < Ops.size());
- while (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
+ while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
// We found two constants, fold them together!
- ConstantInt *Fold = ConstantInt::get(LHSC->getValue()->getValue() +
- RHSC->getValue()->getValue());
- Ops[0] = getConstant(Fold);
+ Ops[0] = getConstant(LHSC->getValue()->getValue() +
+ RHSC->getValue()->getValue());
+ if (Ops.size() == 2) return Ops[0];
Ops.erase(Ops.begin()+1); // Erase the folded element
- if (Ops.size() == 1) return Ops[0];
LHSC = cast<SCEVConstant>(Ops[0]);
}
if (Ops[i] == Ops[i+1]) { // X + Y + Y --> X + Y*2
// Found a match, merge the two values into a multiply, and add any
// remaining values to the result.
- SCEVHandle Two = getIntegerSCEV(2, Ty);
- SCEVHandle Mul = getMulExpr(Ops[i], Two);
+ const SCEV *Two = getIntegerSCEV(2, Ty);
+ const SCEV *Mul = getMulExpr(Ops[i], Two);
if (Ops.size() == 2)
return Mul;
Ops.erase(Ops.begin()+i, Ops.begin()+i+2);
Ops.push_back(Mul);
- return getAddExpr(Ops);
+ return getAddExpr(Ops, HasNUW, HasNSW);
}
- // Now we know the first non-constant operand. Skip past any cast SCEVs.
+ // Check for truncates. If all the operands are truncated from the same
+ // type, see if factoring out the truncate would permit the result to be
+ // folded. eg., trunc(x) + m*trunc(n) --> trunc(x + trunc(m)*n)
+ // if the contents of the resulting outer trunc fold to something simple.
+ for (; Idx < Ops.size() && isa<SCEVTruncateExpr>(Ops[Idx]); ++Idx) {
+ const SCEVTruncateExpr *Trunc = cast<SCEVTruncateExpr>(Ops[Idx]);
+ const Type *DstType = Trunc->getType();
+ const Type *SrcType = Trunc->getOperand()->getType();
+ SmallVector<const SCEV *, 8> LargeOps;
+ bool Ok = true;
+ // Check all the operands to see if they can be represented in the
+ // source type of the truncate.
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
+ if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Ops[i])) {
+ if (T->getOperand()->getType() != SrcType) {
+ Ok = false;
+ break;
+ }
+ LargeOps.push_back(T->getOperand());
+ } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
+ // This could be either sign or zero extension, but sign extension
+ // is much more likely to be foldable here.
+ LargeOps.push_back(getSignExtendExpr(C, SrcType));
+ } else if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Ops[i])) {
+ SmallVector<const SCEV *, 8> LargeMulOps;
+ for (unsigned j = 0, f = M->getNumOperands(); j != f && Ok; ++j) {
+ if (const SCEVTruncateExpr *T =
+ dyn_cast<SCEVTruncateExpr>(M->getOperand(j))) {
+ if (T->getOperand()->getType() != SrcType) {
+ Ok = false;
+ break;
+ }
+ LargeMulOps.push_back(T->getOperand());
+ } else if (const SCEVConstant *C =
+ dyn_cast<SCEVConstant>(M->getOperand(j))) {
+ // This could be either sign or zero extension, but sign extension
+ // is much more likely to be foldable here.
+ LargeMulOps.push_back(getSignExtendExpr(C, SrcType));
+ } else {
+ Ok = false;
+ break;
+ }
+ }
+ if (Ok)
+ LargeOps.push_back(getMulExpr(LargeMulOps));
+ } else {
+ Ok = false;
+ break;
+ }
+ }
+ if (Ok) {
+ // Evaluate the expression in the larger type.
+ 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);
+ }
+ }
+
+ // Skip past any other cast SCEVs.
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddExpr)
++Idx;
// If there are add operands they would be next.
if (Idx < Ops.size()) {
bool DeletedAdd = false;
- while (SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[Idx])) {
+ while (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[Idx])) {
// If we have an add, expand the add operands onto the end of the operands
// list.
Ops.insert(Ops.end(), Add->op_begin(), Add->op_end());
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr)
++Idx;
+ // Check to see if there are any folding opportunities present with
+ // operands multiplied by constant values.
+ if (Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx])) {
+ uint64_t BitWidth = getTypeSizeInBits(Ty);
+ DenseMap<const SCEV *, APInt> M;
+ SmallVector<const SCEV *, 8> NewOps;
+ APInt AccumulatedConstant(BitWidth, 0);
+ if (CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant,
+ Ops, APInt(BitWidth, 1), *this)) {
+ // Some interesting folding opportunity is present, so its worthwhile to
+ // re-generate the operands list. Group the operands by constant scale,
+ // to avoid multiplying by the same constant scale multiple times.
+ std::map<APInt, SmallVector<const SCEV *, 4>, APIntCompare> MulOpLists;
+ for (SmallVector<const SCEV *, 8>::iterator I = NewOps.begin(),
+ E = NewOps.end(); I != E; ++I)
+ MulOpLists[M.find(*I)->second].push_back(*I);
+ // Re-generate the operands list.
+ Ops.clear();
+ if (AccumulatedConstant != 0)
+ Ops.push_back(getConstant(AccumulatedConstant));
+ for (std::map<APInt, SmallVector<const SCEV *, 4>, APIntCompare>::iterator
+ I = MulOpLists.begin(), E = MulOpLists.end(); I != E; ++I)
+ if (I->first != 0)
+ Ops.push_back(getMulExpr(getConstant(I->first),
+ getAddExpr(I->second)));
+ if (Ops.empty())
+ return getIntegerSCEV(0, Ty);
+ if (Ops.size() == 1)
+ return Ops[0];
+ return getAddExpr(Ops);
+ }
+ }
+
// If we are adding something to a multiply expression, make sure the
// something is not already an operand of the multiply. If so, merge it into
// the multiply.
for (; Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx]); ++Idx) {
- SCEVMulExpr *Mul = cast<SCEVMulExpr>(Ops[Idx]);
+ const SCEVMulExpr *Mul = cast<SCEVMulExpr>(Ops[Idx]);
for (unsigned MulOp = 0, e = Mul->getNumOperands(); MulOp != e; ++MulOp) {
- SCEV *MulOpSCEV = Mul->getOperand(MulOp);
+ const SCEV *MulOpSCEV = Mul->getOperand(MulOp);
for (unsigned AddOp = 0, e = Ops.size(); AddOp != e; ++AddOp)
- if (MulOpSCEV == Ops[AddOp] && !isa<SCEVConstant>(MulOpSCEV)) {
+ if (MulOpSCEV == Ops[AddOp] && !isa<SCEVConstant>(Ops[AddOp])) {
// Fold W + X + (X * Y * Z) --> W + (X * ((Y*Z)+1))
- SCEVHandle InnerMul = Mul->getOperand(MulOp == 0);
+ const SCEV *InnerMul = Mul->getOperand(MulOp == 0);
if (Mul->getNumOperands() != 2) {
// If the multiply has more than two operands, we must get the
// Y*Z term.
- std::vector<SCEVHandle> MulOps(Mul->op_begin(), Mul->op_end());
+ SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(), Mul->op_end());
MulOps.erase(MulOps.begin()+MulOp);
InnerMul = getMulExpr(MulOps);
}
- SCEVHandle One = getIntegerSCEV(1, Ty);
- SCEVHandle AddOne = getAddExpr(InnerMul, One);
- SCEVHandle OuterMul = getMulExpr(AddOne, Ops[AddOp]);
+ const SCEV *One = getIntegerSCEV(1, Ty);
+ const SCEV *AddOne = getAddExpr(InnerMul, One);
+ const SCEV *OuterMul = getMulExpr(AddOne, Ops[AddOp]);
if (Ops.size() == 2) return OuterMul;
if (AddOp < Idx) {
Ops.erase(Ops.begin()+AddOp);
for (unsigned OtherMulIdx = Idx+1;
OtherMulIdx < Ops.size() && isa<SCEVMulExpr>(Ops[OtherMulIdx]);
++OtherMulIdx) {
- SCEVMulExpr *OtherMul = cast<SCEVMulExpr>(Ops[OtherMulIdx]);
+ const SCEVMulExpr *OtherMul = cast<SCEVMulExpr>(Ops[OtherMulIdx]);
// If MulOp occurs in OtherMul, we can fold the two multiplies
// together.
for (unsigned OMulOp = 0, e = OtherMul->getNumOperands();
OMulOp != e; ++OMulOp)
if (OtherMul->getOperand(OMulOp) == MulOpSCEV) {
// Fold X + (A*B*C) + (A*D*E) --> X + (A*(B*C+D*E))
- SCEVHandle InnerMul1 = Mul->getOperand(MulOp == 0);
+ const SCEV *InnerMul1 = Mul->getOperand(MulOp == 0);
if (Mul->getNumOperands() != 2) {
- std::vector<SCEVHandle> MulOps(Mul->op_begin(), Mul->op_end());
+ SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
+ Mul->op_end());
MulOps.erase(MulOps.begin()+MulOp);
InnerMul1 = getMulExpr(MulOps);
}
- SCEVHandle InnerMul2 = OtherMul->getOperand(OMulOp == 0);
+ const SCEV *InnerMul2 = OtherMul->getOperand(OMulOp == 0);
if (OtherMul->getNumOperands() != 2) {
- std::vector<SCEVHandle> MulOps(OtherMul->op_begin(),
- OtherMul->op_end());
+ SmallVector<const SCEV *, 4> MulOps(OtherMul->op_begin(),
+ OtherMul->op_end());
MulOps.erase(MulOps.begin()+OMulOp);
InnerMul2 = getMulExpr(MulOps);
}
- SCEVHandle InnerMulSum = getAddExpr(InnerMul1,InnerMul2);
- SCEVHandle OuterMul = getMulExpr(MulOpSCEV, InnerMulSum);
+ const SCEV *InnerMulSum = getAddExpr(InnerMul1,InnerMul2);
+ const SCEV *OuterMul = getMulExpr(MulOpSCEV, InnerMulSum);
if (Ops.size() == 2) return OuterMul;
Ops.erase(Ops.begin()+Idx);
Ops.erase(Ops.begin()+OtherMulIdx-1);
for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
// Scan all of the other operands to this add and add them to the vector if
// they are loop invariant w.r.t. the recurrence.
- std::vector<SCEVHandle> LIOps;
- SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
+ SmallVector<const SCEV *, 8> LIOps;
+ const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
if (Ops[i]->isLoopInvariant(AddRec->getLoop())) {
LIOps.push_back(Ops[i]);
// NLI + LI + {Start,+,Step} --> NLI + {LI+Start,+,Step}
LIOps.push_back(AddRec->getStart());
- std::vector<SCEVHandle> AddRecOps(AddRec->op_begin(), AddRec->op_end());
+ SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(),
+ AddRec->op_end());
AddRecOps[0] = getAddExpr(LIOps);
- SCEVHandle NewRec = getAddRecExpr(AddRecOps, AddRec->getLoop());
+ // 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 OtherIdx = Idx+1;
OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);++OtherIdx)
if (OtherIdx != Idx) {
- SCEVAddRecExpr *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
+ const SCEVAddRecExpr *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
if (AddRec->getLoop() == OtherAddRec->getLoop()) {
// Other + {A,+,B} + {C,+,D} --> Other + {A+C,+,B+D}
- std::vector<SCEVHandle> NewOps(AddRec->op_begin(), AddRec->op_end());
+ SmallVector<const SCEV *, 4> NewOps(AddRec->op_begin(),
+ AddRec->op_end());
for (unsigned i = 0, e = OtherAddRec->getNumOperands(); i != e; ++i) {
if (i >= NewOps.size()) {
NewOps.insert(NewOps.end(), OtherAddRec->op_begin()+i,
}
NewOps[i] = getAddExpr(NewOps[i], OtherAddRec->getOperand(i));
}
- SCEVHandle NewAddRec = getAddRecExpr(NewOps, AddRec->getLoop());
+ const SCEV *NewAddRec = getAddRecExpr(NewOps, AddRec->getLoop());
if (Ops.size() == 2) return NewAddRec;
// Okay, it looks like we really DO need an add expr. Check to see if we
// already have one, otherwise create a new one.
- std::vector<SCEV*> SCEVOps(Ops.begin(), Ops.end());
- SCEVCommutativeExpr *&Result = (*SCEVCommExprs)[std::make_pair(scAddExpr,
- SCEVOps)];
- if (Result == 0) Result = new SCEVAddExpr(Ops);
- return Result;
+ FoldingSetNodeID ID;
+ ID.AddInteger(scAddExpr);
+ ID.AddInteger(Ops.size());
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i)
+ ID.AddPointer(Ops[i]);
+ void *IP = 0;
+ 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;
}
-
-SCEVHandle ScalarEvolution::getMulExpr(std::vector<SCEVHandle> &Ops) {
+/// getMulExpr - Get a canonical multiply expression, or something simpler if
+/// possible.
+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()) ==
+ getEffectiveSCEVType(Ops[0]->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);
+ GroupByComplexity(Ops, LI);
// If there are any constants, fold them together.
unsigned Idx = 0;
- if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
+ if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
// C1*(C2+V) -> C1*C2 + C1*V
if (Ops.size() == 2)
- if (SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1]))
+ if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1]))
if (Add->getNumOperands() == 2 &&
isa<SCEVConstant>(Add->getOperand(0)))
return getAddExpr(getMulExpr(LHSC, Add->getOperand(0)),
getMulExpr(LHSC, Add->getOperand(1)));
-
++Idx;
- while (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[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
} 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);
+ }
}
}
// If there are mul operands inline them all into this expression.
if (Idx < Ops.size()) {
bool DeletedMul = false;
- while (SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) {
+ while (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) {
// If we have an mul, expand the mul operands onto the end of the operands
// list.
Ops.insert(Ops.end(), Mul->op_begin(), Mul->op_end());
for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
// Scan all of the other operands to this mul and add them to the vector if
// they are loop invariant w.r.t. the recurrence.
- std::vector<SCEVHandle> LIOps;
- SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
+ SmallVector<const SCEV *, 8> LIOps;
+ const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
if (Ops[i]->isLoopInvariant(AddRec->getLoop())) {
LIOps.push_back(Ops[i]);
// If we found some loop invariants, fold them into the recurrence.
if (!LIOps.empty()) {
// NLI * LI * {Start,+,Step} --> NLI * {LI*Start,+,LI*Step}
- std::vector<SCEVHandle> NewOps;
+ SmallVector<const SCEV *, 4> NewOps;
NewOps.reserve(AddRec->getNumOperands());
if (LIOps.size() == 1) {
- SCEV *Scale = LIOps[0];
+ const SCEV *Scale = LIOps[0];
for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
NewOps.push_back(getMulExpr(Scale, AddRec->getOperand(i)));
} else {
for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
- std::vector<SCEVHandle> MulOps(LIOps);
+ SmallVector<const SCEV *, 4> MulOps(LIOps.begin(), LIOps.end());
MulOps.push_back(AddRec->getOperand(i));
NewOps.push_back(getMulExpr(MulOps));
}
}
- SCEVHandle 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 OtherIdx = Idx+1;
OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);++OtherIdx)
if (OtherIdx != Idx) {
- SCEVAddRecExpr *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
+ const SCEVAddRecExpr *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
if (AddRec->getLoop() == OtherAddRec->getLoop()) {
// F * G --> {A,+,B} * {C,+,D} --> {A*C,+,F*D + G*B + B*D}
- SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
- SCEVHandle NewStart = getMulExpr(F->getStart(),
+ const SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
+ const SCEV *NewStart = getMulExpr(F->getStart(),
G->getStart());
- SCEVHandle B = F->getStepRecurrence(*this);
- SCEVHandle D = G->getStepRecurrence(*this);
- SCEVHandle NewStep = getAddExpr(getMulExpr(F, D),
+ const SCEV *B = F->getStepRecurrence(*this);
+ const SCEV *D = G->getStepRecurrence(*this);
+ const SCEV *NewStep = getAddExpr(getMulExpr(F, D),
getMulExpr(G, B),
getMulExpr(B, D));
- SCEVHandle NewAddRec = getAddRecExpr(NewStart, NewStep,
+ const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
F->getLoop());
if (Ops.size() == 2) return NewAddRec;
// Okay, it looks like we really DO need an mul expr. Check to see if we
// already have one, otherwise create a new one.
- std::vector<SCEV*> SCEVOps(Ops.begin(), Ops.end());
- SCEVCommutativeExpr *&Result = (*SCEVCommExprs)[std::make_pair(scMulExpr,
- SCEVOps)];
- if (Result == 0)
- Result = new SCEVMulExpr(Ops);
- return Result;
+ FoldingSetNodeID ID;
+ ID.AddInteger(scMulExpr);
+ ID.AddInteger(Ops.size());
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i)
+ ID.AddPointer(Ops[i]);
+ void *IP = 0;
+ 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;
}
-SCEVHandle ScalarEvolution::getUDivExpr(const SCEVHandle &LHS, const SCEVHandle &RHS) {
- if (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
+/// 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()) ==
+ getEffectiveSCEVType(RHS->getType()) &&
+ "SCEVUDivExpr operand types don't match!");
+
+ 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
+
+ // Determine if the division can be folded into the operands of
+ // its operands.
+ // TODO: Generalize this to non-constants by using known-bits information.
+ const Type *Ty = LHS->getType();
+ unsigned LZ = RHSC->getValue()->getValue().countLeadingZeros();
+ unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ;
+ // For non-power-of-two values, effectively round the value up to the
+ // nearest power of two.
+ if (!RHSC->getValue()->getValue().isPowerOf2())
+ ++MaxShiftAmt;
+ const IntegerType *ExtTy =
+ 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 =
+ dyn_cast<SCEVConstant>(AR->getStepRecurrence(*this)))
+ if (!Step->getValue()->getValue()
+ .urem(RHSC->getValue()->getValue()) &&
+ getZeroExtendExpr(AR, ExtTy) ==
+ getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
+ getZeroExtendExpr(Step, ExtTy),
+ AR->getLoop())) {
+ SmallVector<const SCEV *, 4> Operands;
+ for (unsigned i = 0, e = AR->getNumOperands(); i != e; ++i)
+ Operands.push_back(getUDivExpr(AR->getOperand(i), RHS));
+ return getAddRecExpr(Operands, AR->getLoop());
+ }
+ // (A*B)/C --> A*(B/C) if safe and B/C can be folded.
+ if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(LHS)) {
+ SmallVector<const SCEV *, 4> Operands;
+ for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i)
+ Operands.push_back(getZeroExtendExpr(M->getOperand(i), ExtTy));
+ if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands))
+ // Find an operand that's safely divisible.
+ for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
+ const SCEV *Op = M->getOperand(i);
+ const SCEV *Div = getUDivExpr(Op, RHSC);
+ if (!isa<SCEVUDivExpr>(Div) && getMulExpr(Div, RHSC) == Op) {
+ const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
+ Operands = SmallVector<const SCEV *, 4>(MOperands.begin(),
+ MOperands.end());
+ Operands[i] = Div;
+ return getMulExpr(Operands);
+ }
+ }
+ }
+ // (A+B)/C --> (A/C + B/C) if safe and A/C and B/C can be folded.
+ if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(LHS)) {
+ SmallVector<const SCEV *, 4> Operands;
+ for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i)
+ Operands.push_back(getZeroExtendExpr(A->getOperand(i), ExtTy));
+ if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) {
+ Operands.clear();
+ for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) {
+ const SCEV *Op = getUDivExpr(A->getOperand(i), RHS);
+ if (isa<SCEVUDivExpr>(Op) || getMulExpr(Op, RHS) != A->getOperand(i))
+ break;
+ Operands.push_back(Op);
+ }
+ if (Operands.size() == A->getNumOperands())
+ return getAddExpr(Operands);
+ }
+ }
- if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
+ // Fold if both operands are constant.
+ if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
Constant *LHSCV = LHSC->getValue();
Constant *RHSCV = RHSC->getValue();
- return getUnknown(ConstantExpr::getUDiv(LHSCV, RHSCV));
+ return getConstant(cast<ConstantInt>(ConstantExpr::getUDiv(LHSCV,
+ RHSCV)));
}
}
- // FIXME: implement folding of (X*4)/4 when we know X*4 doesn't overflow.
-
- SCEVUDivExpr *&Result = (*SCEVUDivs)[std::make_pair(LHS, RHS)];
- if (Result == 0) Result = new SCEVUDivExpr(LHS, RHS);
- return Result;
+ FoldingSetNodeID ID;
+ ID.AddInteger(scUDivExpr);
+ ID.AddPointer(LHS);
+ ID.AddPointer(RHS);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVUDivExpr>();
+ new (S) SCEVUDivExpr(ID, LHS, RHS);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
}
-/// SCEVAddRecExpr::get - Get a add recurrence expression for the
-/// specified loop. Simplify the expression as much as possible.
-SCEVHandle ScalarEvolution::getAddRecExpr(const SCEVHandle &Start,
- const SCEVHandle &Step, const Loop *L) {
- std::vector<SCEVHandle> Operands;
+/// 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,
+ bool HasNUW, bool HasNSW) {
+ SmallVector<const SCEV *, 4> Operands;
Operands.push_back(Start);
- if (SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
+ if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
if (StepChrec->getLoop() == L) {
Operands.insert(Operands.end(), StepChrec->op_begin(),
StepChrec->op_end());
}
Operands.push_back(Step);
- return getAddRecExpr(Operands, L);
+ return getAddRecExpr(Operands, L, HasNUW, HasNSW);
}
-/// SCEVAddRecExpr::get - Get a add recurrence expression for the
-/// specified loop. Simplify the expression as much as possible.
-SCEVHandle ScalarEvolution::getAddRecExpr(std::vector<SCEVHandle> &Operands,
- const Loop *L) {
+/// 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,
+ bool HasNUW, bool HasNSW) {
if (Operands.size() == 1) return Operands[0];
+#ifndef NDEBUG
+ for (unsigned i = 1, e = Operands.size(); i != e; ++i)
+ assert(getEffectiveSCEVType(Operands[i]->getType()) ==
+ getEffectiveSCEVType(Operands[0]->getType()) &&
+ "SCEVAddRecExpr operand types don't match!");
+#endif
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 (SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) {
- const Loop* NestedLoop = NestedAR->getLoop();
- if (L->getLoopDepth() < NestedLoop->getLoopDepth()) {
- std::vector<SCEVHandle> NestedOperands(NestedAR->op_begin(),
- NestedAR->op_end());
- SCEVHandle NestedARHandle(NestedAR);
+ if (const SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) {
+ 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());
Operands[0] = NestedAR->getStart();
- NestedOperands[0] = getAddRecExpr(Operands, L);
- return getAddRecExpr(NestedOperands, NestedLoop);
+ // AddRecs require their operands be loop-invariant with respect to their
+ // loops. Don't perform this transformation if it would break this
+ // requirement.
+ bool AllInvariant = true;
+ for (unsigned i = 0, e = Operands.size(); i != e; ++i)
+ if (!Operands[i]->isLoopInvariant(L)) {
+ AllInvariant = false;
+ break;
+ }
+ if (AllInvariant) {
+ NestedOperands[0] = getAddRecExpr(Operands, L);
+ AllInvariant = true;
+ for (unsigned i = 0, e = NestedOperands.size(); i != e; ++i)
+ if (!NestedOperands[i]->isLoopInvariant(NestedLoop)) {
+ AllInvariant = false;
+ break;
+ }
+ if (AllInvariant)
+ // Ok, both add recurrences are valid after the transformation.
+ return getAddRecExpr(NestedOperands, NestedLoop, HasNUW, HasNSW);
+ }
+ // Reset Operands to its original state.
+ Operands[0] = NestedAR;
}
}
- SCEVAddRecExpr *&Result =
- (*SCEVAddRecExprs)[std::make_pair(L, std::vector<SCEV*>(Operands.begin(),
- Operands.end()))];
- if (Result == 0) Result = new SCEVAddRecExpr(Operands, L);
- return Result;
+ // 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());
+ for (unsigned i = 0, e = Operands.size(); i != e; ++i)
+ ID.AddPointer(Operands[i]);
+ ID.AddPointer(L);
+ void *IP = 0;
+ 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;
}
-SCEVHandle ScalarEvolution::getSMaxExpr(const SCEVHandle &LHS,
- const SCEVHandle &RHS) {
- std::vector<SCEVHandle> Ops;
+const SCEV *ScalarEvolution::getSMaxExpr(const SCEV *LHS,
+ const SCEV *RHS) {
+ SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
return getSMaxExpr(Ops);
}
-SCEVHandle ScalarEvolution::getSMaxExpr(std::vector<SCEVHandle> Ops) {
+const SCEV *
+ScalarEvolution::getSMaxExpr(SmallVectorImpl<const SCEV *> &Ops) {
assert(!Ops.empty() && "Cannot get empty smax!");
if (Ops.size() == 1) return Ops[0];
+#ifndef NDEBUG
+ for (unsigned i = 1, e = Ops.size(); i != e; ++i)
+ assert(getEffectiveSCEVType(Ops[i]->getType()) ==
+ getEffectiveSCEVType(Ops[0]->getType()) &&
+ "SCEVSMaxExpr operand types don't match!");
+#endif
// Sort by complexity, this groups all similar expression types together.
- GroupByComplexity(Ops);
+ GroupByComplexity(Ops, LI);
// If there are any constants, fold them together.
unsigned Idx = 0;
- if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
+ if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
++Idx;
assert(Idx < Ops.size());
- while (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
+ 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);
LHSC = cast<SCEVConstant>(Ops[0]);
}
- // If we are left with a constant -inf, strip it off.
+ // If we are left with a constant minimum-int, strip it off.
if (cast<SCEVConstant>(Ops[0])->getValue()->isMinValue(true)) {
Ops.erase(Ops.begin());
--Idx;
+ } else if (cast<SCEVConstant>(Ops[0])->getValue()->isMaxValue(true)) {
+ // If we have an smax with a constant maximum-int, it will always be
+ // maximum-int.
+ return Ops[0];
}
}
// onto our operand list, and recurse to simplify.
if (Idx < Ops.size()) {
bool DeletedSMax = false;
- while (SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(Ops[Idx])) {
+ while (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(Ops[Idx])) {
Ops.insert(Ops.end(), SMax->op_begin(), SMax->op_end());
Ops.erase(Ops.begin()+Idx);
DeletedSMax = true;
// Okay, it looks like we really DO need an smax expr. Check to see if we
// already have one, otherwise create a new one.
- std::vector<SCEV*> SCEVOps(Ops.begin(), Ops.end());
- SCEVCommutativeExpr *&Result = (*SCEVCommExprs)[std::make_pair(scSMaxExpr,
- SCEVOps)];
- if (Result == 0) Result = new SCEVSMaxExpr(Ops);
- return Result;
+ FoldingSetNodeID ID;
+ ID.AddInteger(scSMaxExpr);
+ ID.AddInteger(Ops.size());
+ 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<SCEVSMaxExpr>();
+ new (S) SCEVSMaxExpr(ID, Ops);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
}
-SCEVHandle ScalarEvolution::getUMaxExpr(const SCEVHandle &LHS,
- const SCEVHandle &RHS) {
- std::vector<SCEVHandle> Ops;
+const SCEV *ScalarEvolution::getUMaxExpr(const SCEV *LHS,
+ const SCEV *RHS) {
+ SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
return getUMaxExpr(Ops);
}
-SCEVHandle ScalarEvolution::getUMaxExpr(std::vector<SCEVHandle> Ops) {
+const SCEV *
+ScalarEvolution::getUMaxExpr(SmallVectorImpl<const SCEV *> &Ops) {
assert(!Ops.empty() && "Cannot get empty umax!");
if (Ops.size() == 1) return Ops[0];
+#ifndef NDEBUG
+ for (unsigned i = 1, e = Ops.size(); i != e; ++i)
+ assert(getEffectiveSCEVType(Ops[i]->getType()) ==
+ getEffectiveSCEVType(Ops[0]->getType()) &&
+ "SCEVUMaxExpr operand types don't match!");
+#endif
// Sort by complexity, this groups all similar expression types together.
- GroupByComplexity(Ops);
+ GroupByComplexity(Ops, LI);
// If there are any constants, fold them together.
unsigned Idx = 0;
- if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
+ if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
++Idx;
assert(Idx < Ops.size());
- while (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
+ 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);
LHSC = cast<SCEVConstant>(Ops[0]);
}
- // If we are left with a constant zero, strip it off.
+ // If we are left with a constant minimum-int, strip it off.
if (cast<SCEVConstant>(Ops[0])->getValue()->isMinValue(false)) {
Ops.erase(Ops.begin());
--Idx;
+ } else if (cast<SCEVConstant>(Ops[0])->getValue()->isMaxValue(false)) {
+ // If we have an umax with a constant maximum-int, it will always be
+ // maximum-int.
+ return Ops[0];
}
}
// onto our operand list, and recurse to simplify.
if (Idx < Ops.size()) {
bool DeletedUMax = false;
- while (SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(Ops[Idx])) {
+ while (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(Ops[Idx])) {
Ops.insert(Ops.end(), UMax->op_begin(), UMax->op_end());
Ops.erase(Ops.begin()+Idx);
DeletedUMax = true;
// Okay, it looks like we really DO need a umax expr. Check to see if we
// already have one, otherwise create a new one.
- std::vector<SCEV*> SCEVOps(Ops.begin(), Ops.end());
- SCEVCommutativeExpr *&Result = (*SCEVCommExprs)[std::make_pair(scUMaxExpr,
- SCEVOps)];
- if (Result == 0) Result = new SCEVUMaxExpr(Ops);
- return Result;
+ FoldingSetNodeID ID;
+ ID.AddInteger(scUMaxExpr);
+ ID.AddInteger(Ops.size());
+ 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<SCEVUMaxExpr>();
+ new (S) SCEVUMaxExpr(ID, Ops);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
}
-SCEVHandle ScalarEvolution::getUnknown(Value *V) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
- return getConstant(CI);
- if (isa<ConstantPointerNull>(V))
- return getIntegerSCEV(0, V->getType());
- SCEVUnknown *&Result = (*SCEVUnknowns)[V];
- if (Result == 0) Result = new SCEVUnknown(V);
- return Result;
+const SCEV *ScalarEvolution::getSMinExpr(const SCEV *LHS,
+ const SCEV *RHS) {
+ // ~smax(~x, ~y) == smin(x, y).
+ return getNotSCEV(getSMaxExpr(getNotSCEV(LHS), getNotSCEV(RHS)));
}
-//===----------------------------------------------------------------------===//
-// Basic SCEV Analysis and PHI Idiom Recognition Code
-//
+const SCEV *ScalarEvolution::getUMinExpr(const SCEV *LHS,
+ const SCEV *RHS) {
+ // ~umax(~x, ~y) == umin(x, y)
+ return getNotSCEV(getUMaxExpr(getNotSCEV(LHS), getNotSCEV(RHS)));
+}
-/// deleteValueFromRecords - This method should be called by the
-/// client before it removes an instruction from the program, to make sure
-/// that no dangling references are left around.
-void ScalarEvolution::deleteValueFromRecords(Value *V) {
- SmallVector<Value *, 16> Worklist;
+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);
+}
- if (Scalars.erase(V)) {
- if (PHINode *PN = dyn_cast<PHINode>(V))
- ConstantEvolutionLoopExitValue.erase(PN);
- Worklist.push_back(V);
- }
+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);
+}
- while (!Worklist.empty()) {
- Value *VV = Worklist.back();
- Worklist.pop_back();
-
- for (Instruction::use_iterator UI = VV->use_begin(), UE = VV->use_end();
- UI != UE; ++UI) {
- Instruction *Inst = cast<Instruction>(*UI);
- if (Scalars.erase(Inst)) {
- if (PHINode *PN = dyn_cast<PHINode>(VV))
- ConstantEvolutionLoopExitValue.erase(PN);
- Worklist.push_back(Inst);
- }
- }
- }
+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));
+ return getTruncateOrZeroExtend(getSCEV(C), Ty);
+}
+
+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) {
+ // Don't attempt to do anything other than create a SCEVUnknown object
+ // here. createSCEV only calls getUnknown after checking for all other
+ // interesting possibilities, and any other code that calls getUnknown
+ // is doing so in order to hide a value from SCEV canonicalization.
+
+ FoldingSetNodeID ID;
+ ID.AddInteger(scUnknown);
+ ID.AddPointer(V);
+ void *IP = 0;
+ if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ SCEV *S = SCEVAllocator.Allocate<SCEVUnknown>();
+ new (S) SCEVUnknown(ID, V);
+ UniqueSCEVs.InsertNode(S, IP);
+ return S;
}
+//===----------------------------------------------------------------------===//
+// Basic SCEV Analysis and PHI Idiom Recognition Code
+//
+
/// isSCEVable - Test if values of the given type are analyzable within
/// the SCEV framework. This primarily includes integer types, and it
/// 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());
}
-SCEVHandle ScalarEvolution::getCouldNotCompute() {
- return UnknownValue;
+const SCEV *ScalarEvolution::getCouldNotCompute() {
+ return &CouldNotCompute;
}
/// getSCEV - Return an existing SCEV if it exists, otherwise analyze the
/// expression and create a new one.
-SCEVHandle ScalarEvolution::getSCEV(Value *V) {
+const SCEV *ScalarEvolution::getSCEV(Value *V) {
assert(isSCEVable(V->getType()) && "Value is not SCEVable!");
- std::map<Value*, SCEVHandle>::iterator I = Scalars.find(V);
+ std::map<SCEVCallbackVH, const SCEV *>::iterator I = Scalars.find(V);
if (I != Scalars.end()) return I->second;
- SCEVHandle S = createSCEV(V);
- Scalars.insert(std::make_pair(V, S));
+ const SCEV *S = createSCEV(V);
+ Scalars.insert(std::make_pair(SCEVCallbackVH(V, this), S));
return S;
}
-/// getIntegerSCEV - Given an integer or FP type, create a constant for the
+/// getIntegerSCEV - Given a SCEVable type, create a constant for the
/// specified signed integer value and return a SCEV for the constant.
-SCEVHandle ScalarEvolution::getIntegerSCEV(int Val, const Type *Ty) {
- Ty = getEffectiveSCEVType(Ty);
- Constant *C;
- if (Val == 0)
- C = Constant::getNullValue(Ty);
- else if (Ty->isFloatingPoint())
- C = ConstantFP::get(APFloat(Ty==Type::FloatTy ? APFloat::IEEEsingle :
- APFloat::IEEEdouble, Val));
- else
- C = ConstantInt::get(Ty, Val);
- return getUnknown(C);
+const SCEV *ScalarEvolution::getIntegerSCEV(int64_t Val, const Type *Ty) {
+ const IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
+ return getConstant(ConstantInt::get(ITy, Val));
}
/// getNegativeSCEV - Return a SCEV corresponding to -V = -1*V
///
-SCEVHandle ScalarEvolution::getNegativeSCEV(const SCEVHandle &V) {
- if (SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
- return getUnknown(ConstantExpr::getNeg(VC->getValue()));
+const SCEV *ScalarEvolution::getNegativeSCEV(const SCEV *V) {
+ if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
+ return getConstant(
+ cast<ConstantInt>(ConstantExpr::getNeg(VC->getValue())));
const Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
- return getMulExpr(V, getConstant(ConstantInt::getAllOnesValue(Ty)));
+ return getMulExpr(V,
+ getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))));
}
/// getNotSCEV - Return a SCEV corresponding to ~V = -1-V
-SCEVHandle ScalarEvolution::getNotSCEV(const SCEVHandle &V) {
- if (SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
- return getUnknown(ConstantExpr::getNot(VC->getValue()));
+const SCEV *ScalarEvolution::getNotSCEV(const SCEV *V) {
+ if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
+ return getConstant(
+ cast<ConstantInt>(ConstantExpr::getNot(VC->getValue())));
const Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
- SCEVHandle AllOnes = getConstant(ConstantInt::getAllOnesValue(Ty));
+ const SCEV *AllOnes =
+ getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty)));
return getMinusSCEV(AllOnes, V);
}
/// getMinusSCEV - Return a SCEV corresponding to LHS - RHS.
///
-SCEVHandle ScalarEvolution::getMinusSCEV(const SCEVHandle &LHS,
- const SCEVHandle &RHS) {
+const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS,
+ const SCEV *RHS) {
// X - Y --> X + -Y
return getAddExpr(LHS, getNegativeSCEV(RHS));
}
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion of the
/// input value to the specified type. If the type must be extended, it is zero
/// extended.
-SCEVHandle
-ScalarEvolution::getTruncateOrZeroExtend(const SCEVHandle &V,
+const SCEV *
+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
/// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion of the
/// input value to the specified type. If the type must be extended, it is sign
/// extended.
-SCEVHandle
-ScalarEvolution::getTruncateOrSignExtend(const SCEVHandle &V,
+const SCEV *
+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
return getSignExtendExpr(V, Ty);
}
-/// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value for
-/// the specified instruction and replaces any references to the symbolic value
-/// SymName with the specified value. This is used during PHI resolution.
-void ScalarEvolution::
-ReplaceSymbolicValueWithConcrete(Instruction *I, const SCEVHandle &SymName,
- const SCEVHandle &NewVal) {
- std::map<Value*, SCEVHandle>::iterator SI = Scalars.find(I);
- if (SI == Scalars.end()) return;
+/// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of the
+/// input value to the specified type. If the type must be extended, it is zero
+/// extended. The conversion must not be narrowing.
+const SCEV *
+ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, const Type *Ty) {
+ const Type *SrcTy = V->getType();
+ 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!");
+ if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+ return V; // No conversion
+ return getZeroExtendExpr(V, Ty);
+}
+
+/// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of the
+/// input value to the specified type. If the type must be extended, it is sign
+/// extended. The conversion must not be narrowing.
+const SCEV *
+ScalarEvolution::getNoopOrSignExtend(const SCEV *V, const Type *Ty) {
+ const Type *SrcTy = V->getType();
+ 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!");
+ if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+ return V; // No conversion
+ return getSignExtendExpr(V, Ty);
+}
+
+/// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of
+/// the input value to the specified type. If the type must be extended,
+/// it is extended with unspecified bits. The conversion must not be
+/// narrowing.
+const SCEV *
+ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, const Type *Ty) {
+ const Type *SrcTy = V->getType();
+ 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!");
+ if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+ return V; // No conversion
+ return getAnyExtendExpr(V, Ty);
+}
+
+/// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
+/// input value to the specified type. The conversion must not be widening.
+const SCEV *
+ScalarEvolution::getTruncateOrNoop(const SCEV *V, const Type *Ty) {
+ const Type *SrcTy = V->getType();
+ 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!");
+ if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+ return V; // No conversion
+ return getTruncateExpr(V, Ty);
+}
+
+/// getUMaxFromMismatchedTypes - Promote the operands to the wider of
+/// the types using zero-extension, and then perform a umax operation
+/// with them.
+const SCEV *ScalarEvolution::getUMaxFromMismatchedTypes(const SCEV *LHS,
+ const SCEV *RHS) {
+ const SCEV *PromotedLHS = LHS;
+ const SCEV *PromotedRHS = RHS;
+
+ if (getTypeSizeInBits(LHS->getType()) > getTypeSizeInBits(RHS->getType()))
+ PromotedRHS = getZeroExtendExpr(RHS, LHS->getType());
+ else
+ PromotedLHS = getNoopOrZeroExtend(LHS, RHS->getType());
+
+ return getUMaxExpr(PromotedLHS, PromotedRHS);
+}
+
+/// getUMinFromMismatchedTypes - Promote the operands to the wider of
+/// the types using zero-extension, and then perform a umin operation
+/// with them.
+const SCEV *ScalarEvolution::getUMinFromMismatchedTypes(const SCEV *LHS,
+ const SCEV *RHS) {
+ const SCEV *PromotedLHS = LHS;
+ const SCEV *PromotedRHS = RHS;
+
+ if (getTypeSizeInBits(LHS->getType()) > getTypeSizeInBits(RHS->getType()))
+ PromotedRHS = getZeroExtendExpr(RHS, LHS->getType());
+ else
+ PromotedLHS = getNoopOrZeroExtend(LHS, RHS->getType());
+
+ return getUMinExpr(PromotedLHS, PromotedRHS);
+}
+
+/// 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));
+}
- SCEVHandle NV =
- SI->second->replaceSymbolicValuesWithConcrete(SymName, NewVal, *this);
- if (NV == SI->second) return; // No change.
+/// 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::ForgetSymbolicName(Instruction *I, const SCEV *SymName) {
+ SmallVector<Instruction *, 16> Worklist;
+ PushDefUseChildren(I, Worklist);
+
+ SmallPtrSet<Instruction *, 8> Visited;
+ Visited.insert(I);
+ while (!Worklist.empty()) {
+ Instruction *I = Worklist.pop_back_val();
+ if (!Visited.insert(I)) continue;
+
+ 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;
- SI->second = NV; // Update the scalars map!
+ // 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
/// a loop header, making it a potential recurrence, or it doesn't.
///
-SCEVHandle ScalarEvolution::createNodeForPHI(PHINode *PN) {
+const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
if (PN->getNumIncomingValues() == 2) // The loops have been canonicalized.
if (const Loop *L = LI->getLoopFor(PN->getParent()))
if (L->getHeader() == PN->getParent()) {
unsigned BackEdge = IncomingEdge^1;
// While we are analyzing this PHI node, handle its value symbolically.
- SCEVHandle SymbolicName = getUnknown(PN);
+ const SCEV *SymbolicName = getUnknown(PN);
assert(Scalars.find(PN) == Scalars.end() &&
"PHI node already processed?");
- Scalars.insert(std::make_pair(PN, SymbolicName));
+ Scalars.insert(std::make_pair(SCEVCallbackVH(PN, this), SymbolicName));
// Using this symbolic name for the PHI, analyze the value coming around
// the back-edge.
- SCEVHandle 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.
// If the value coming around the backedge is an add with the symbolic
// value we just inserted, then we found a simple induction variable!
- if (SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) {
+ if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) {
// If there is a single occurrence of the symbolic value, replace it
// with a recurrence.
unsigned FoundIndex = Add->getNumOperands();
if (FoundIndex != Add->getNumOperands()) {
// Create an add with everything but the specified operand.
- std::vector<SCEVHandle> Ops;
+ SmallVector<const SCEV *, 8> Ops;
for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
if (i != FoundIndex)
Ops.push_back(Add->getOperand(i));
- SCEVHandle Accum = getAddExpr(Ops);
+ const SCEV *Accum = getAddExpr(Ops);
// This is not a valid addrec if the step amount is varying each
// loop iteration, but is not itself an addrec in this loop.
if (Accum->isLoopInvariant(L) ||
(isa<SCEVAddRecExpr>(Accum) &&
cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) {
- SCEVHandle StartVal = getSCEV(PN->getIncomingValue(IncomingEdge));
- SCEVHandle PHISCEV = getAddRecExpr(StartVal, Accum, 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 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 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;
}
}
- } else if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(BEValue)) {
+ } else if (const SCEVAddRecExpr *AddRec =
+ dyn_cast<SCEVAddRecExpr>(BEValue)) {
// Otherwise, this could be a loop like this:
// i = 0; for (j = 1; ..; ++j) { .... i = j; }
// In this case, j = {1,+,1} and BEValue is j.
// Because the other in-value of i (0) fits the evolution of BEValue
// i really is an addrec evolution.
if (AddRec->getLoop() == L && AddRec->isAffine()) {
- SCEVHandle StartVal = getSCEV(PN->getIncomingValue(IncomingEdge));
+ const SCEV *StartVal = getSCEV(PN->getIncomingValue(IncomingEdge));
// If StartVal = j.start - j.stride, we can use StartVal as the
// initial step of the addrec evolution.
if (StartVal == getMinusSCEV(AddRec->getOperand(0),
AddRec->getOperand(1))) {
- SCEVHandle PHISCEV =
+ const SCEV *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(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.
+ if (!cast<PointerType>(Base->getType())->getElementType()->isSized())
+ return getUnknown(GEP);
+ const SCEV *TotalOffset = getIntegerSCEV(0, IntPtrTy);
+ gep_type_iterator GTI = gep_type_begin(GEP);
+ for (GetElementPtrInst::op_iterator I = next(GEP->op_begin()),
+ E = GEP->op_end();
+ I != E; ++I) {
+ Value *Index = *I;
+ // 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.
+ unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
+ TotalOffset = getAddExpr(TotalOffset,
+ getOffsetOfExpr(STy, FieldNo),
+ /*HasNUW=*/false, /*HasNSW=*/InBounds);
+ } else {
+ // For an array, add the element offset, explicitly scaled.
+ const SCEV *LocalOffset = getSCEV(Index);
+ // 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,
+ /*HasNUW=*/false, /*HasNSW=*/InBounds);
+}
+
/// GetMinTrailingZeros - Determine the minimum number of zero bits that S is
/// guaranteed to end in (at every loop iteration). It is, at the same time,
/// the minimum number of times S is divisible by 2. For example, given {4,+,8}
/// it returns 2. If S is guaranteed to be 0, it returns the bitwidth of S.
-static uint32_t GetMinTrailingZeros(SCEVHandle S, const ScalarEvolution &SE) {
- if (SCEVConstant *C = dyn_cast<SCEVConstant>(S))
+uint32_t
+ScalarEvolution::GetMinTrailingZeros(const SCEV *S) {
+ if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
return C->getValue()->getValue().countTrailingZeros();
- if (SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S))
- return std::min(GetMinTrailingZeros(T->getOperand(), SE),
- (uint32_t)SE.getTypeSizeInBits(T->getType()));
+ if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S))
+ return std::min(GetMinTrailingZeros(T->getOperand()),
+ (uint32_t)getTypeSizeInBits(T->getType()));
- if (SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) {
- uint32_t OpRes = GetMinTrailingZeros(E->getOperand(), SE);
- return OpRes == SE.getTypeSizeInBits(E->getOperand()->getType()) ?
- SE.getTypeSizeInBits(E->getOperand()->getType()) : OpRes;
+ if (const SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) {
+ uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
+ return OpRes == getTypeSizeInBits(E->getOperand()->getType()) ?
+ getTypeSizeInBits(E->getType()) : OpRes;
}
- if (SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) {
- uint32_t OpRes = GetMinTrailingZeros(E->getOperand(), SE);
- return OpRes == SE.getTypeSizeInBits(E->getOperand()->getType()) ?
- SE.getTypeSizeInBits(E->getOperand()->getType()) : OpRes;
+ if (const SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) {
+ uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
+ return OpRes == getTypeSizeInBits(E->getOperand()->getType()) ?
+ getTypeSizeInBits(E->getType()) : OpRes;
}
- if (SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
+ if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
// The result is the min of all operands results.
- uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0), SE);
+ uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
- MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i), SE));
+ MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
return MinOpRes;
}
- if (SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
+ if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
// The result is the sum of all operands results.
- uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0), SE);
- uint32_t BitWidth = SE.getTypeSizeInBits(M->getType());
+ uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0));
+ uint32_t BitWidth = getTypeSizeInBits(M->getType());
for (unsigned i = 1, e = M->getNumOperands();
SumOpRes != BitWidth && i != e; ++i)
- SumOpRes = std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i), SE),
+ SumOpRes = std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i)),
BitWidth);
return SumOpRes;
}
- if (SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
+ if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
// The result is the min of all operands results.
- uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0), SE);
+ uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
- MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i), SE));
+ MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
return MinOpRes;
}
- if (SCEVSMaxExpr *M = dyn_cast<SCEVSMaxExpr>(S)) {
+ if (const SCEVSMaxExpr *M = dyn_cast<SCEVSMaxExpr>(S)) {
// The result is the min of all operands results.
- uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0), SE);
+ uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
- MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i), SE));
+ MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
return MinOpRes;
}
- if (SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) {
+ if (const SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) {
// The result is the min of all operands results.
- uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0), SE);
+ uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
- MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i), SE));
+ MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
return MinOpRes;
}
- // SCEVUDivExpr, SCEVUnknown
+ if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
+ // For a SCEVUnknown, ask ValueTracking.
+ unsigned BitWidth = getTypeSizeInBits(U->getType());
+ APInt Mask = APInt::getAllOnesValue(BitWidth);
+ APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
+ ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones);
+ return Zeros.countTrailingOnes();
+ }
+
+ // SCEVUDivExpr
return 0;
}
+/// getUnsignedRange - Determine the unsigned range for a particular SCEV.
+///
+ConstantRange
+ScalarEvolution::getUnsignedRange(const SCEV *S) {
+
+ 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 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 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 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 ConservativeResult.intersectWith(X);
+ }
+
+ if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
+ ConstantRange X = getUnsignedRange(UDiv->getLHS());
+ ConstantRange Y = getUnsignedRange(UDiv->getRHS());
+ return ConservativeResult.intersectWith(X.udiv(Y));
+ }
+
+ if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
+ ConstantRange X = getUnsignedRange(ZExt->getOperand());
+ return ConservativeResult.intersectWith(X.zeroExtend(BitWidth));
+ }
+
+ if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
+ ConstantRange X = getUnsignedRange(SExt->getOperand());
+ return ConservativeResult.intersectWith(X.signExtend(BitWidth));
+ }
+
+ if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
+ ConstantRange X = getUnsignedRange(Trunc->getOperand());
+ return ConservativeResult.intersectWith(X.truncate(BitWidth));
+ }
+
+ if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
+ // 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 (!isa<SCEVCouldNotCompute>(MaxBECount) &&
+ getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
+ MaxBECount = getNoopOrZeroExtend(MaxBECount, Ty);
+
+ const SCEV *Start = AddRec->getStart();
+ const SCEV *End = AddRec->evaluateAtIteration(MaxBECount, *this);
+
+ // Check for overflow.
+ if (!AddRec->hasNoUnsignedWrap())
+ return ConservativeResult;
+
+ ConstantRange StartRange = getUnsignedRange(Start);
+ ConstantRange EndRange = getUnsignedRange(End);
+ APInt Min = APIntOps::umin(StartRange.getUnsignedMin(),
+ EndRange.getUnsignedMin());
+ APInt Max = APIntOps::umax(StartRange.getUnsignedMax(),
+ EndRange.getUnsignedMax());
+ if (Min.isMinValue() && Max.isMaxValue())
+ 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());
+ APInt Mask = APInt::getAllOnesValue(BitWidth);
+ APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
+ ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD);
+ if (Ones == ~Zeros + 1)
+ return ConservativeResult;
+ return ConservativeResult.intersectWith(ConstantRange(Ones, ~Zeros + 1));
+ }
+
+ return ConservativeResult;
+}
+
+/// getSignedRange - Determine the signed range for a particular SCEV.
+///
+ConstantRange
+ScalarEvolution::getSignedRange(const SCEV *S) {
+
+ 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 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 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 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 ConservativeResult.intersectWith(X);
+ }
+
+ if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
+ ConstantRange X = getSignedRange(UDiv->getLHS());
+ ConstantRange Y = getSignedRange(UDiv->getRHS());
+ return ConservativeResult.intersectWith(X.udiv(Y));
+ }
+
+ if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
+ ConstantRange X = getSignedRange(ZExt->getOperand());
+ return ConservativeResult.intersectWith(X.zeroExtend(BitWidth));
+ }
+
+ if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
+ ConstantRange X = getSignedRange(SExt->getOperand());
+ return ConservativeResult.intersectWith(X.signExtend(BitWidth));
+ }
+
+ if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
+ ConstantRange X = getSignedRange(Trunc->getOperand());
+ return ConservativeResult.intersectWith(X.truncate(BitWidth));
+ }
+
+ if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
+ // 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 (!isa<SCEVCouldNotCompute>(MaxBECount) &&
+ getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
+ MaxBECount = getNoopOrZeroExtend(MaxBECount, Ty);
+
+ const SCEV *Start = AddRec->getStart();
+ const SCEV *End = AddRec->evaluateAtIteration(MaxBECount, *this);
+
+ // Check for overflow.
+ if (!AddRec->hasNoSignedWrap())
+ return ConservativeResult;
+
+ ConstantRange StartRange = getSignedRange(Start);
+ ConstantRange EndRange = getSignedRange(End);
+ APInt Min = APIntOps::smin(StartRange.getSignedMin(),
+ EndRange.getSignedMin());
+ APInt Max = APIntOps::smax(StartRange.getSignedMax(),
+ EndRange.getSignedMax());
+ if (Min.isMinSignedValue() && Max.isMaxSignedValue())
+ return ConservativeResult;
+ return ConservativeResult.intersectWith(ConstantRange(Min, Max+1));
+ }
+ }
+
+ return ConservativeResult;
+ }
+
+ if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
+ // For a SCEVUnknown, ask ValueTracking.
+ if (!U->getValue()->getType()->isInteger() && !TD)
+ return ConservativeResult;
+ unsigned NS = ComputeNumSignBits(U->getValue(), TD);
+ if (NS == 1)
+ return ConservativeResult;
+ return ConservativeResult.intersectWith(
+ ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1),
+ APInt::getSignedMaxValue(BitWidth).ashr(NS - 1)+1));
+ }
+
+ return ConservativeResult;
+}
+
/// createSCEV - We know that there is no SCEV for the specified value.
/// Analyze the expression.
///
-SCEVHandle ScalarEvolution::createSCEV(Value *V) {
+const SCEV *ScalarEvolution::createSCEV(Value *V) {
if (!isSCEVable(V->getType()))
return getUnknown(V);
Opcode = I->getOpcode();
else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
Opcode = CE->getOpcode();
+ else if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
+ return getConstant(CI);
+ else if (isa<ConstantPointerNull>(V))
+ 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 (CI->isAllOnesValue())
return getSCEV(U->getOperand(0));
const APInt &A = CI->getValue();
- unsigned Ones = A.countTrailingOnes();
- if (APIntOps::isMask(Ones, A))
+
+ // Instcombine's ShrinkDemandedConstant may strip bits out of
+ // constants, obscuring what would otherwise be a low-bits mask.
+ // Use ComputeMaskedBits to compute what ShrinkDemandedConstant
+ // knew about to reconstruct a low-bits mask value.
+ unsigned LZ = A.countLeadingZeros();
+ unsigned BitWidth = A.getBitWidth();
+ APInt AllOnes = APInt::getAllOnesValue(BitWidth);
+ APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+ ComputeMaskedBits(U->getOperand(0), AllOnes, KnownZero, KnownOne, TD);
+
+ APInt EffectiveMask = APInt::getLowBitsSet(BitWidth, BitWidth - LZ);
+
+ if (LZ != 0 && !((~A & ~KnownZero) & EffectiveMask))
return
getZeroExtendExpr(getTruncateExpr(getSCEV(U->getOperand(0)),
- IntegerType::get(Ones)),
+ IntegerType::get(getContext(), BitWidth - LZ)),
U->getType());
}
break;
+
case Instruction::Or:
// If the RHS of the Or is a constant, we may have something like:
// X*4+1 which got turned into X*4|1. Handle this as an Add so loop
// In order for this transformation to be safe, the LHS must be of the
// form X*(2^n) and the Or constant must be less than 2^n.
if (ConstantInt *CI = dyn_cast<ConstantInt>(U->getOperand(1))) {
- SCEVHandle LHS = getSCEV(U->getOperand(0));
+ const SCEV *LHS = getSCEV(U->getOperand(0));
const APInt &CIVal = CI->getValue();
- if (GetMinTrailingZeros(LHS, *this) >=
- (CIVal.getBitWidth() - CIVal.countLeadingZeros()))
- return getAddExpr(LHS, getSCEV(U->getOperand(1)));
+ if (GetMinTrailingZeros(LHS) >=
+ (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:
getSCEV(U->getOperand(1)));
// If the RHS of xor is -1, then this is a not operation.
- else if (CI->isAllOnesValue())
+ if (CI->isAllOnesValue())
return getNotSCEV(getSCEV(U->getOperand(0)));
+
+ // Model xor(and(x, C), C) as and(~x, C), if C is a low-bits mask.
+ // This is a variant of the check for xor with -1, and it handles
+ // the case where instcombine has trimmed non-demanded bits out
+ // of an xor with -1.
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(U->getOperand(0)))
+ if (ConstantInt *LCI = dyn_cast<ConstantInt>(BO->getOperand(1)))
+ if (BO->getOpcode() == Instruction::And &&
+ LCI->getValue() == CI->getValue())
+ if (const SCEVZeroExtendExpr *Z =
+ dyn_cast<SCEVZeroExtendExpr>(getSCEV(U->getOperand(0)))) {
+ const Type *UTy = U->getType();
+ const SCEV *Z0 = Z->getOperand();
+ const Type *Z0Ty = Z0->getType();
+ unsigned Z0TySize = getTypeSizeInBits(Z0Ty);
+
+ // If C is a low-bits mask, the zero extend is zerving to
+ // mask off the high bits. Complement the operand and
+ // re-apply the zext.
+ if (APIntOps::isMask(Z0TySize, CI->getValue()))
+ return getZeroExtendExpr(getNotSCEV(Z0), UTy);
+
+ // If C is a single bit, it may be in the sign-bit position
+ // before the zero-extend. In this case, represent the xor
+ // using an add, which is equivalent, and re-apply the zext.
+ APInt Trunc = APInt(CI->getValue()).trunc(Z0TySize);
+ if (APInt(Trunc).zext(getTypeSizeInBits(UTy)) == CI->getValue() &&
+ Trunc.isSignBit())
+ return getZeroExtendExpr(getAddExpr(Z0, getConstant(Trunc)),
+ UTy);
+ }
}
break;
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();
- Constant *X = ConstantInt::get(
+ 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();
- Constant *X = ConstantInt::get(
+ 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 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());
-
- case Instruction::GetElementPtr: {
- if (!TD) break; // Without TD we can't analyze pointers.
- const Type *IntPtrTy = TD->getIntPtrType();
- Value *Base = U->getOperand(0);
- SCEVHandle TotalOffset = getIntegerSCEV(0, IntPtrTy);
- gep_type_iterator GTI = gep_type_begin(U);
- for (GetElementPtrInst::op_iterator I = next(U->op_begin()),
- E = U->op_end();
- I != E; ++I) {
- Value *Index = *I;
- // 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));
- } else {
- // For an array, add the element offset, explicitly scaled.
- SCEVHandle LocalOffset = getSCEV(Index);
- if (!isa<PointerType>(LocalOffset->getType()))
- // Getelementptr indicies are signed.
- LocalOffset = getTruncateOrSignExtend(LocalOffset,
- IntPtrTy);
- LocalOffset =
- getMulExpr(LocalOffset,
- getIntegerSCEV(TD->getTypePaddedSize(*GTI),
- IntPtrTy));
- TotalOffset = getAddExpr(TotalOffset, LocalOffset);
- }
- }
- return getAddExpr(getSCEV(Base), TotalOffset);
- }
+ // 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(cast<GEPOperator>(U));
case Instruction::PHI:
return createNodeForPHI(cast<PHINode>(U));
if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
return getSMaxExpr(getSCEV(LHS), getSCEV(RHS));
else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
- // ~smax(~x, ~y) == smin(x, y).
- return getNotSCEV(getSMaxExpr(
- getNotSCEV(getSCEV(LHS)),
- getNotSCEV(getSCEV(RHS))));
+ return getSMinExpr(getSCEV(LHS), getSCEV(RHS));
break;
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
return getUMaxExpr(getSCEV(LHS), getSCEV(RHS));
else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
- // ~umax(~x, ~y) == umin(x, y)
- return getNotSCEV(getUMaxExpr(getNotSCEV(getSCEV(LHS)),
- getNotSCEV(getSCEV(RHS))));
+ return getUMinExpr(getSCEV(LHS), getSCEV(RHS));
+ break;
+ case ICmpInst::ICMP_NE:
+ // n != 0 ? n : 1 -> umax(n, 1)
+ if (LHS == U->getOperand(1) &&
+ isa<ConstantInt>(U->getOperand(2)) &&
+ cast<ConstantInt>(U->getOperand(2))->isOne() &&
+ isa<ConstantInt>(RHS) &&
+ cast<ConstantInt>(RHS)->isZero())
+ return getUMaxExpr(getSCEV(LHS), getSCEV(U->getOperand(2)));
+ break;
+ case ICmpInst::ICMP_EQ:
+ // n == 0 ? 1 : n -> umax(n, 1)
+ if (LHS == U->getOperand(2) &&
+ isa<ConstantInt>(U->getOperand(1)) &&
+ cast<ConstantInt>(U->getOperand(1))->isOne() &&
+ isa<ConstantInt>(RHS) &&
+ cast<ConstantInt>(RHS)->isZero())
+ return getUMaxExpr(getSCEV(LHS), getSCEV(U->getOperand(1)));
break;
default:
break;
/// loop-invariant backedge-taken count (see
/// hasLoopInvariantBackedgeTakenCount).
///
-SCEVHandle ScalarEvolution::getBackedgeTakenCount(const Loop *L) {
+const SCEV *ScalarEvolution::getBackedgeTakenCount(const Loop *L) {
+ return getBackedgeTakenInfo(L).Exact;
+}
+
+/// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except
+/// return the least SCEV value that is known never to be less than the
+/// actual backedge taken count.
+const SCEV *ScalarEvolution::getMaxBackedgeTakenCount(const Loop *L) {
+ return getBackedgeTakenInfo(L).Max;
+}
+
+/// PushLoopPHIs - Push PHI nodes in the header of the given loop
+/// onto the given Worklist.
+static void
+PushLoopPHIs(const Loop *L, SmallVectorImpl<Instruction *> &Worklist) {
+ BasicBlock *Header = L->getHeader();
+
+ // Push all Loop-header PHIs onto the Worklist stack.
+ for (BasicBlock::iterator I = Header->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I)
+ Worklist.push_back(PN);
+}
+
+const ScalarEvolution::BackedgeTakenInfo &
+ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
// Initially insert a CouldNotCompute for this loop. If the insertion
// succeeds, procede to actually compute a backedge-taken count and
// 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*, SCEVHandle>::iterator, bool> Pair =
+ std::pair<std::map<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair =
BackedgeTakenCounts.insert(std::make_pair(L, getCouldNotCompute()));
if (Pair.second) {
- SCEVHandle ItCount = ComputeBackedgeTakenCount(L);
- if (ItCount != UnknownValue) {
- assert(ItCount->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;
- // Now that we know 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.
- for (BasicBlock::iterator I = L->getHeader()->begin();
- PHINode *PN = dyn_cast<PHINode>(I); ++I)
- deleteValueFromRecords(PN);
+ // Update the value in the map.
+ Pair.first->second = BECount;
+ } else {
+ if (BECount.Max != getCouldNotCompute())
+ // Update the value in the map.
+ 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 forgetLoop, except that
+ // it handles SCEVUnknown PHI nodes specially.
+ if (BECount.hasAnyInfo()) {
+ SmallVector<Instruction *, 16> Worklist;
+ PushLoopPHIs(L, Worklist);
+
+ SmallPtrSet<Instruction *, 8> Visited;
+ while (!Worklist.empty()) {
+ Instruction *I = Worklist.pop_back_val();
+ if (!Visited.insert(I)) continue;
+
+ 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
+ // 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);
+ }
+ if (PHINode *PN = dyn_cast<PHINode>(I))
+ ConstantEvolutionLoopExitValue.erase(PN);
+ }
- // Update the value in the map.
- Pair.first->second = ItCount;
- } else if (isa<PHINode>(L->getHeader()->begin())) {
- // Only count loops that have phi nodes as not being computable.
- ++NumTripCountsNotComputed;
+ PushDefUseChildren(I, Worklist);
+ }
}
}
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);
+
+ SmallPtrSet<Instruction *, 8> Visited;
+ while (!Worklist.empty()) {
+ Instruction *I = Worklist.pop_back_val();
+ if (!Visited.insert(I)) continue;
+
+ std::map<SCEVCallbackVH, const SCEV *>::iterator It =
+ Scalars.find(static_cast<Value *>(I));
+ if (It != Scalars.end()) {
+ ValuesAtScopes.erase(It->second);
+ Scalars.erase(It);
+ if (PHINode *PN = dyn_cast<PHINode>(I))
+ ConstantEvolutionLoopExitValue.erase(PN);
+ }
+
+ PushDefUseChildren(I, Worklist);
+ }
}
/// ComputeBackedgeTakenCount - Compute the number of times the backedge
/// of the specified loop will execute.
-SCEVHandle ScalarEvolution::ComputeBackedgeTakenCount(const Loop *L) {
- // If the loop has a non-one exit block count, we can't analyze it.
- SmallVector<BasicBlock*, 8> ExitBlocks;
- L->getExitBlocks(ExitBlocks);
- if (ExitBlocks.size() != 1) return UnknownValue;
-
- // Okay, there is one exit block. Try to find the condition that causes the
- // loop to be exited.
- BasicBlock *ExitBlock = ExitBlocks[0];
-
- BasicBlock *ExitingBlock = 0;
- for (pred_iterator PI = pred_begin(ExitBlock), E = pred_end(ExitBlock);
- PI != E; ++PI)
- if (L->contains(*PI)) {
- if (ExitingBlock == 0)
- ExitingBlock = *PI;
+ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::ComputeBackedgeTakenCount(const Loop *L) {
+ SmallVector<BasicBlock *, 8> ExitingBlocks;
+ L->getExitingBlocks(ExitingBlocks);
+
+ // Examine all exits and pick the most conservative values.
+ const SCEV *BECount = getCouldNotCompute();
+ const SCEV *MaxBECount = getCouldNotCompute();
+ bool CouldNotComputeBECount = false;
+ for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) {
+ BackedgeTakenInfo NewBTI =
+ ComputeBackedgeTakenCountFromExit(L, ExitingBlocks[i]);
+
+ if (NewBTI.Exact == getCouldNotCompute()) {
+ // We couldn't compute an exact value for this exit, so
+ // we won't be able to compute an exact value for the loop.
+ CouldNotComputeBECount = true;
+ BECount = getCouldNotCompute();
+ } else if (!CouldNotComputeBECount) {
+ if (BECount == getCouldNotCompute())
+ BECount = NewBTI.Exact;
else
- return UnknownValue; // More than one block exiting!
+ BECount = getUMinFromMismatchedTypes(BECount, NewBTI.Exact);
}
- assert(ExitingBlock && "No exits from loop, something is broken!");
+ if (MaxBECount == getCouldNotCompute())
+ MaxBECount = NewBTI.Max;
+ else if (NewBTI.Max != getCouldNotCompute())
+ MaxBECount = getUMinFromMismatchedTypes(MaxBECount, NewBTI.Max);
+ }
+
+ return BackedgeTakenInfo(BECount, MaxBECount);
+}
+
+/// ComputeBackedgeTakenCountFromExit - Compute the number of times the backedge
+/// of the specified loop will execute if it exits via the specified block.
+ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::ComputeBackedgeTakenCountFromExit(const Loop *L,
+ BasicBlock *ExitingBlock) {
- // Okay, we've computed the exiting block. See what condition causes us to
- // exit.
+ // Okay, we've chosen an exiting block. See what condition causes us to
+ // exit at this block.
//
// FIXME: we should be able to handle switch instructions (with a single exit)
BranchInst *ExitBr = dyn_cast<BranchInst>(ExitingBlock->getTerminator());
- if (ExitBr == 0) return UnknownValue;
+ if (ExitBr == 0) return getCouldNotCompute();
assert(ExitBr->isConditional() && "If unconditional, it can't be in loop!");
-
+
// At this point, we know we have a conditional branch that determines whether
// the loop is exited. However, we don't know if the branch is executed each
// time through the loop. If not, then the execution count of the branch will
// Currently we check for this by checking to see if the Exit branch goes to
// the loop header. If so, we know it will always execute the same number of
// times as the loop. We also handle the case where the exit block *is* the
- // loop header. This is common for un-rotated loops. More extensive analysis
- // could be done to handle more cases here.
+ // loop header. This is common for un-rotated loops.
+ //
+ // If both of those tests fail, walk up the unique predecessor chain to the
+ // header, stopping if there is an edge that doesn't exit the loop. If the
+ // header is reached, the execution count of the branch will be equal to the
+ // trip count of the loop.
+ //
+ // More extensive analysis could be done to handle more cases here.
+ //
if (ExitBr->getSuccessor(0) != L->getHeader() &&
ExitBr->getSuccessor(1) != L->getHeader() &&
- ExitBr->getParent() != L->getHeader())
- return UnknownValue;
-
- ICmpInst *ExitCond = dyn_cast<ICmpInst>(ExitBr->getCondition());
-
- // If it's not an integer comparison then compute it the hard way.
- // Note that ICmpInst deals with pointer comparisons too so we must check
- // the type of the operand.
- if (ExitCond == 0 || isa<PointerType>(ExitCond->getOperand(0)->getType()))
- return ComputeBackedgeTakenCountExhaustively(L, ExitBr->getCondition(),
- ExitBr->getSuccessor(0) == ExitBlock);
+ ExitBr->getParent() != L->getHeader()) {
+ // The simple checks failed, try climbing the unique predecessor chain
+ // up to the header.
+ bool Ok = false;
+ for (BasicBlock *BB = ExitBr->getParent(); BB; ) {
+ BasicBlock *Pred = BB->getUniquePredecessor();
+ if (!Pred)
+ return getCouldNotCompute();
+ TerminatorInst *PredTerm = Pred->getTerminator();
+ for (unsigned i = 0, e = PredTerm->getNumSuccessors(); i != e; ++i) {
+ BasicBlock *PredSucc = PredTerm->getSuccessor(i);
+ if (PredSucc == BB)
+ continue;
+ // If the predecessor has a successor that isn't BB and isn't
+ // outside the loop, assume the worst.
+ if (L->contains(PredSucc))
+ return getCouldNotCompute();
+ }
+ if (Pred == L->getHeader()) {
+ Ok = true;
+ break;
+ }
+ BB = Pred;
+ }
+ if (!Ok)
+ return getCouldNotCompute();
+ }
+
+ // Procede to the next level to examine the exit condition expression.
+ return ComputeBackedgeTakenCountFromExitCond(L, ExitBr->getCondition(),
+ ExitBr->getSuccessor(0),
+ ExitBr->getSuccessor(1));
+}
+
+/// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the
+/// backedge of the specified loop will execute if its exit condition
+/// were a conditional branch of ExitCond, TBB, and FBB.
+ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::ComputeBackedgeTakenCountFromExitCond(const Loop *L,
+ Value *ExitCond,
+ BasicBlock *TBB,
+ BasicBlock *FBB) {
+ // Check if the controlling expression for this loop is an And or Or.
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(ExitCond)) {
+ if (BO->getOpcode() == Instruction::And) {
+ // Recurse on the operands of the and.
+ BackedgeTakenInfo BTI0 =
+ ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(0), TBB, FBB);
+ BackedgeTakenInfo BTI1 =
+ ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(1), TBB, FBB);
+ const SCEV *BECount = getCouldNotCompute();
+ const SCEV *MaxBECount = getCouldNotCompute();
+ if (L->contains(TBB)) {
+ // Both conditions must be true for the loop to continue executing.
+ // Choose the less conservative count.
+ if (BTI0.Exact == getCouldNotCompute() ||
+ BTI1.Exact == getCouldNotCompute())
+ BECount = getCouldNotCompute();
+ else
+ BECount = getUMinFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
+ if (BTI0.Max == getCouldNotCompute())
+ MaxBECount = BTI1.Max;
+ else if (BTI1.Max == getCouldNotCompute())
+ MaxBECount = BTI0.Max;
+ else
+ MaxBECount = getUMinFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ } else {
+ // Both conditions must be true for the loop to exit.
+ assert(L->contains(FBB) && "Loop block has no successor in loop!");
+ if (BTI0.Exact != getCouldNotCompute() &&
+ BTI1.Exact != getCouldNotCompute())
+ BECount = getUMaxFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
+ if (BTI0.Max != getCouldNotCompute() &&
+ BTI1.Max != getCouldNotCompute())
+ MaxBECount = getUMaxFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ }
+
+ return BackedgeTakenInfo(BECount, MaxBECount);
+ }
+ if (BO->getOpcode() == Instruction::Or) {
+ // Recurse on the operands of the or.
+ BackedgeTakenInfo BTI0 =
+ ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(0), TBB, FBB);
+ BackedgeTakenInfo BTI1 =
+ ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(1), TBB, FBB);
+ const SCEV *BECount = getCouldNotCompute();
+ const SCEV *MaxBECount = getCouldNotCompute();
+ if (L->contains(FBB)) {
+ // Both conditions must be false for the loop to continue executing.
+ // Choose the less conservative count.
+ if (BTI0.Exact == getCouldNotCompute() ||
+ BTI1.Exact == getCouldNotCompute())
+ BECount = getCouldNotCompute();
+ else
+ BECount = getUMinFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
+ if (BTI0.Max == getCouldNotCompute())
+ MaxBECount = BTI1.Max;
+ else if (BTI1.Max == getCouldNotCompute())
+ MaxBECount = BTI0.Max;
+ else
+ MaxBECount = getUMinFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ } else {
+ // Both conditions must be false for the loop to exit.
+ assert(L->contains(TBB) && "Loop block has no successor in loop!");
+ if (BTI0.Exact != getCouldNotCompute() &&
+ BTI1.Exact != getCouldNotCompute())
+ BECount = getUMaxFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
+ if (BTI0.Max != getCouldNotCompute() &&
+ BTI1.Max != getCouldNotCompute())
+ MaxBECount = getUMaxFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ }
+
+ return BackedgeTakenInfo(BECount, MaxBECount);
+ }
+ }
+
+ // With an icmp, it may be feasible to compute an exact backedge-taken count.
+ // Procede to the next level to examine the icmp.
+ if (ICmpInst *ExitCondICmp = dyn_cast<ICmpInst>(ExitCond))
+ return ComputeBackedgeTakenCountFromExitCondICmp(L, ExitCondICmp, TBB, FBB);
+
+ // If it's not an integer or pointer comparison then compute it the hard way.
+ return ComputeBackedgeTakenCountExhaustively(L, ExitCond, !L->contains(TBB));
+}
+
+/// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of times the
+/// backedge of the specified loop will execute if its exit condition
+/// were a conditional branch of the ICmpInst ExitCond, TBB, and FBB.
+ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
+ ICmpInst *ExitCond,
+ BasicBlock *TBB,
+ BasicBlock *FBB) {
// If the condition was exit on true, convert the condition to exit on false
ICmpInst::Predicate Cond;
- if (ExitBr->getSuccessor(1) == ExitBlock)
+ if (!L->contains(FBB))
Cond = ExitCond->getPredicate();
else
Cond = ExitCond->getInversePredicate();
// Handle common loops like: for (X = "string"; *X; ++X)
if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0)))
if (Constant *RHS = dyn_cast<Constant>(ExitCond->getOperand(1))) {
- SCEVHandle ItCnt =
+ const SCEV *ItCnt =
ComputeLoadConstantCompareBackedgeTakenCount(LI, RHS, L, Cond);
- if (!isa<SCEVCouldNotCompute>(ItCnt)) return ItCnt;
+ if (!isa<SCEVCouldNotCompute>(ItCnt)) {
+ unsigned BitWidth = getTypeSizeInBits(ItCnt->getType());
+ return BackedgeTakenInfo(ItCnt,
+ isa<SCEVConstant>(ItCnt) ? ItCnt :
+ getConstant(APInt::getMaxValue(BitWidth)-1));
+ }
}
- SCEVHandle LHS = getSCEV(ExitCond->getOperand(0));
- SCEVHandle RHS = getSCEV(ExitCond->getOperand(1));
+ const SCEV *LHS = getSCEV(ExitCond->getOperand(0));
+ const SCEV *RHS = getSCEV(ExitCond->getOperand(1));
// Try to evaluate any dependencies out of the loop.
- SCEVHandle Tmp = getSCEVAtScope(LHS, L);
- if (!isa<SCEVCouldNotCompute>(Tmp)) LHS = Tmp;
- Tmp = getSCEVAtScope(RHS, L);
- if (!isa<SCEVCouldNotCompute>(Tmp)) RHS = Tmp;
+ LHS = getSCEVAtScope(LHS, L);
+ RHS = getSCEVAtScope(RHS, L);
- // At this point, we would like to compute how many iterations of the
+ // At this point, we would like to compute how many iterations of the
// loop the predicate will return true for these inputs.
if (LHS->isLoopInvariant(L) && !RHS->isLoopInvariant(L)) {
// If there is a loop-invariant, force it into the RHS.
// If we have a comparison of a chrec against a constant, try to use value
// ranges to answer this query.
- if (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS))
- if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS))
+ if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS))
+ if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS))
if (AddRec->getLoop() == L) {
- // Form the comparison range using the constant of the correct type so
- // that the ConstantRange class knows to do a signed or unsigned
- // comparison.
- ConstantInt *CompVal = RHSC->getValue();
- const Type *RealTy = ExitCond->getOperand(0)->getType();
- CompVal = dyn_cast<ConstantInt>(
- ConstantExpr::getBitCast(CompVal, RealTy));
- if (CompVal) {
- // Form the constant range.
- ConstantRange CompRange(
- ICmpInst::makeConstantRange(Cond, CompVal->getValue()));
-
- SCEVHandle Ret = AddRec->getNumIterationsInRange(CompRange, *this);
- if (!isa<SCEVCouldNotCompute>(Ret)) return Ret;
- }
+ // Form the constant range.
+ ConstantRange CompRange(
+ ICmpInst::makeConstantRange(Cond, RHSC->getValue()->getValue()));
+
+ const SCEV *Ret = AddRec->getNumIterationsInRange(CompRange, *this);
+ if (!isa<SCEVCouldNotCompute>(Ret)) return Ret;
}
switch (Cond) {
case ICmpInst::ICMP_NE: { // while (X != Y)
// Convert to: while (X-Y != 0)
- SCEVHandle TC = HowFarToZero(getMinusSCEV(LHS, RHS), L);
+ const SCEV *TC = HowFarToZero(getMinusSCEV(LHS, RHS), L);
if (!isa<SCEVCouldNotCompute>(TC)) return TC;
break;
}
- case ICmpInst::ICMP_EQ: {
- // Convert to: while (X-Y == 0) // while (X == Y)
- SCEVHandle TC = HowFarToNonZero(getMinusSCEV(LHS, RHS), L);
+ 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;
}
case ICmpInst::ICMP_SLT: {
- SCEVHandle TC = HowManyLessThans(LHS, RHS, L, true);
- if (!isa<SCEVCouldNotCompute>(TC)) return TC;
+ BackedgeTakenInfo BTI = HowManyLessThans(LHS, RHS, L, true);
+ if (BTI.hasAnyInfo()) return BTI;
break;
}
case ICmpInst::ICMP_SGT: {
- SCEVHandle TC = HowManyLessThans(getNotSCEV(LHS),
- getNotSCEV(RHS), L, true);
- if (!isa<SCEVCouldNotCompute>(TC)) return TC;
+ BackedgeTakenInfo BTI = HowManyLessThans(getNotSCEV(LHS),
+ getNotSCEV(RHS), L, true);
+ if (BTI.hasAnyInfo()) return BTI;
break;
}
case ICmpInst::ICMP_ULT: {
- SCEVHandle TC = HowManyLessThans(LHS, RHS, L, false);
- if (!isa<SCEVCouldNotCompute>(TC)) return TC;
+ BackedgeTakenInfo BTI = HowManyLessThans(LHS, RHS, L, false);
+ if (BTI.hasAnyInfo()) return BTI;
break;
}
case ICmpInst::ICMP_UGT: {
- SCEVHandle TC = HowManyLessThans(getNotSCEV(LHS),
- getNotSCEV(RHS), L, false);
- if (!isa<SCEVCouldNotCompute>(TC)) return TC;
+ BackedgeTakenInfo BTI = HowManyLessThans(getNotSCEV(LHS),
+ getNotSCEV(RHS), L, false);
+ if (BTI.hasAnyInfo()) return BTI;
break;
}
default:
#if 0
- errs() << "ComputeBackedgeTakenCount ";
+ dbgs() << "ComputeBackedgeTakenCount ";
if (ExitCond->getOperand(0)->getType()->isUnsigned())
- errs() << "[unsigned] ";
- errs() << *LHS << " "
- << Instruction::getOpcodeName(Instruction::ICmp)
+ dbgs() << "[unsigned] ";
+ dbgs() << *LHS << " "
+ << Instruction::getOpcodeName(Instruction::ICmp)
<< " " << *RHS << "\n";
#endif
break;
}
return
- ComputeBackedgeTakenCountExhaustively(L, ExitCond,
- ExitBr->getSuccessor(0) == ExitBlock);
+ ComputeBackedgeTakenCountExhaustively(L, ExitCond, !L->contains(TBB));
}
static ConstantInt *
EvaluateConstantChrecAtConstant(const SCEVAddRecExpr *AddRec, ConstantInt *C,
ScalarEvolution &SE) {
- SCEVHandle InVal = SE.getConstant(C);
- SCEVHandle Val = AddRec->evaluateAtIteration(InVal, SE);
+ const SCEV *InVal = SE.getConstant(C);
+ const SCEV *Val = AddRec->evaluateAtIteration(InVal, SE);
assert(isa<SCEVConstant>(Val) &&
"Evaluation of SCEV at constant didn't fold correctly?");
return cast<SCEVConstant>(Val)->getValue();
if (Idx >= ATy->getNumElements()) return 0; // Bogus program
Init = Constant::getNullValue(ATy->getElementType());
} else {
- assert(0 && "Unknown constant aggregate type!");
+ llvm_unreachable("Unknown constant aggregate type!");
}
return 0;
} else {
/// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition of
/// 'icmp op load X, cst', try to see if we can compute the backedge
/// execution count.
-SCEVHandle ScalarEvolution::
-ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI, Constant *RHS,
- const Loop *L,
- ICmpInst::Predicate predicate) {
- if (LI->isVolatile()) return UnknownValue;
+const SCEV *
+ScalarEvolution::ComputeLoadConstantCompareBackedgeTakenCount(
+ LoadInst *LI,
+ Constant *RHS,
+ const Loop *L,
+ ICmpInst::Predicate predicate) {
+ if (LI->isVolatile()) return getCouldNotCompute();
// Check to see if the loaded pointer is a getelementptr of a global.
GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0));
- if (!GEP) return UnknownValue;
+ if (!GEP) return getCouldNotCompute();
// 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 UnknownValue;
+ return getCouldNotCompute();
// Okay, we allow one non-constant index into the GEP instruction.
Value *VarIdx = 0;
if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i))) {
Indexes.push_back(CI);
} else if (!isa<ConstantInt>(GEP->getOperand(i))) {
- if (VarIdx) return UnknownValue; // Multiple non-constant idx's.
+ if (VarIdx) return getCouldNotCompute(); // Multiple non-constant idx's.
VarIdx = GEP->getOperand(i);
VarIdxNum = i-2;
Indexes.push_back(0);
// Okay, we know we have a (load (gep GV, 0, X)) comparison with a constant.
// Check to see if X is a loop variant variable value now.
- SCEVHandle Idx = getSCEV(VarIdx);
- SCEVHandle Tmp = getSCEVAtScope(Idx, L);
- if (!isa<SCEVCouldNotCompute>(Tmp)) Idx = Tmp;
+ const SCEV *Idx = getSCEV(VarIdx);
+ Idx = getSCEVAtScope(Idx, L);
// We can only recognize very limited forms of loop index expressions, in
// particular, only affine AddRec's like {C1,+,C2}.
- SCEVAddRecExpr *IdxExpr = dyn_cast<SCEVAddRecExpr>(Idx);
+ const SCEVAddRecExpr *IdxExpr = dyn_cast<SCEVAddRecExpr>(Idx);
if (!IdxExpr || !IdxExpr->isAffine() || IdxExpr->isLoopInvariant(L) ||
!isa<SCEVConstant>(IdxExpr->getOperand(0)) ||
!isa<SCEVConstant>(IdxExpr->getOperand(1)))
- return UnknownValue;
+ return getCouldNotCompute();
unsigned MaxSteps = MaxBruteForceIterations;
for (unsigned IterationNum = 0; IterationNum != MaxSteps; ++IterationNum) {
- ConstantInt *ItCst =
- ConstantInt::get(IdxExpr->getType(), IterationNum);
+ ConstantInt *ItCst = ConstantInt::get(
+ cast<IntegerType>(IdxExpr->getType()), IterationNum);
ConstantInt *Val = EvaluateConstantChrecAtConstant(IdxExpr, ItCst, *this);
// Form the GEP offset.
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
return getConstant(ItCst); // Found terminating iteration!
}
}
- return UnknownValue;
+ return getCouldNotCompute();
}
// 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;
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());
- else
- return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size());
+ 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
/// in the header of its containing loop, we know the loop executes a
/// constant number of times, and the PHI node is just a recurrence
/// involving constants, fold it.
-Constant *ScalarEvolution::
-getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs, const Loop *L){
+Constant *
+ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
+ const APInt &BEs,
+ const Loop *L) {
std::map<PHINode*, Constant*>::iterator I =
ConstantEvolutionLoopExitValue.find(PN);
if (I != ConstantEvolutionLoopExitValue.end())
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
-/// evaluate the trip count of the loop, return UnknownValue.
-SCEVHandle ScalarEvolution::
-ComputeBackedgeTakenCountExhaustively(const Loop *L, Value *Cond, bool ExitWhen) {
+/// evaluate the trip count of the loop, return getCouldNotCompute().
+const SCEV *
+ScalarEvolution::ComputeBackedgeTakenCountExhaustively(const Loop *L,
+ Value *Cond,
+ bool ExitWhen) {
PHINode *PN = getConstantEvolvingPHI(Cond, L);
- if (PN == 0) return UnknownValue;
+ if (PN == 0) return getCouldNotCompute();
// Since the loop is canonicalized, the PHI node must have two entries. One
// entry must be a constant (coming in from outside of the loop), and the
bool SecondIsBackedge = L->contains(PN->getIncomingBlock(1));
Constant *StartCST =
dyn_cast<Constant>(PN->getIncomingValue(!SecondIsBackedge));
- if (StartCST == 0) return UnknownValue; // Must be a constant.
+ if (StartCST == 0) return getCouldNotCompute(); // Must be a constant.
Value *BEValue = PN->getIncomingValue(SecondIsBackedge);
PHINode *PN2 = getConstantEvolvingPHI(BEValue, L);
- if (PN2 != PN) return UnknownValue; // Not derived from same PHI.
+ if (PN2 != PN) return getCouldNotCompute(); // Not derived from same PHI.
// Okay, we find a PHI node that defines the trip count of this loop. Execute
// the loop symbolically to determine when the condition gets a value of
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 UnknownValue;
+ if (!CondVal) return getCouldNotCompute();
if (CondVal->getValue() == uint64_t(ExitWhen)) {
- ConstantEvolutionLoopExitValue[PN] = PHIVal;
++NumBruteForceTripCountsComputed;
- return getConstant(ConstantInt::get(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 UnknownValue; // Couldn't evaluate or not making progress...
+ return getCouldNotCompute();// Couldn't evaluate or not making progress...
PHIVal = NextPHI;
}
// Too many iterations were needed to evaluate.
- return UnknownValue;
+ return getCouldNotCompute();
}
-/// getSCEVAtScope - Compute the value of the specified expression within the
-/// indicated loop (which may be null to indicate in no loop). If the
-/// expression cannot be evaluated, return UnknownValue.
-SCEVHandle ScalarEvolution::getSCEVAtScope(SCEV *V, const Loop *L) {
- // FIXME: this should be turned into a virtual method on SCEV!
+/// 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.
+///
+/// This method can be used to compute the exit value for a variable defined
+/// in a loop by querying what the value will hold in the parent 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) {
+ // 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
// exit value from the loop without using SCEVs.
- if (SCEVUnknown *SU = dyn_cast<SCEVUnknown>(V)) {
+ if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(V)) {
if (Instruction *I = dyn_cast<Instruction>(SU->getValue())) {
const Loop *LI = (*this->LI)[I->getParent()];
if (LI && LI->getParentLoop() == L) // Looking for loop exit value.
// to see if the loop that contains it has a known backedge-taken
// count. If so, we may be able to force computation of the exit
// value.
- SCEVHandle BackedgeTakenCount = getBackedgeTakenCount(LI);
- if (SCEVConstant *BTCC =
+ const SCEV *BackedgeTakenCount = getBackedgeTakenCount(LI);
+ if (const SCEVConstant *BTCC =
dyn_cast<SCEVConstant>(BackedgeTakenCount)) {
// Okay, we know how many times the containing loop executes. If
// this is a constant evolving PHI node, get the final value at
Constant *RV = getConstantEvolutionLoopExitValue(PN,
BTCC->getValue()->getValue(),
LI);
- if (RV) return getUnknown(RV);
+ if (RV) return getSCEV(RV);
}
}
// If any of the operands is non-constant and if they are
// non-integer and non-pointer, don't even try to analyze them
// with scev techniques.
- if (!isa<IntegerType>(Op->getType()) &&
- !isa<PointerType>(Op->getType()))
+ if (!isSCEVable(Op->getType()))
return V;
- SCEVHandle OpV = getSCEVAtScope(getSCEV(Op), L);
- if (SCEVConstant *SC = dyn_cast<SCEVConstant>(OpV))
- Operands.push_back(ConstantExpr::getIntegerCast(SC->getValue(),
- Op->getType(),
- false));
- else if (SCEVUnknown *SU = dyn_cast<SCEVUnknown>(OpV)) {
- if (Constant *C = dyn_cast<Constant>(SU->getValue()))
- Operands.push_back(ConstantExpr::getIntegerCast(C,
- Op->getType(),
- false));
- else
+ const SCEV *OpV = getSCEVAtScope(Op, L);
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(OpV)) {
+ Constant *C = SC->getValue();
+ if (C->getType() != Op->getType())
+ C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
+ Op->getType(),
+ false),
+ C, Op->getType());
+ Operands.push_back(C);
+ } else if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(OpV)) {
+ if (Constant *C = dyn_cast<Constant>(SU->getValue())) {
+ if (C->getType() != Op->getType())
+ C =
+ ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
+ Op->getType(),
+ false),
+ C, Op->getType());
+ Operands.push_back(C);
+ } else
return V;
} else {
return V;
}
}
}
-
+
Constant *C;
if (const CmpInst *CI = dyn_cast<CmpInst>(I))
C = ConstantFoldCompareInstOperands(CI->getPredicate(),
- &Operands[0], Operands.size());
+ Operands[0], Operands[1], TD);
else
C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size());
- return getUnknown(C);
+ &Operands[0], Operands.size(), TD);
+ return getSCEV(C);
}
}
return V;
}
- if (SCEVCommutativeExpr *Comm = dyn_cast<SCEVCommutativeExpr>(V)) {
+ if (const SCEVCommutativeExpr *Comm = dyn_cast<SCEVCommutativeExpr>(V)) {
// Avoid performing the look-up in the common case where the specified
// expression has no loop-variant portions.
for (unsigned i = 0, e = Comm->getNumOperands(); i != e; ++i) {
- SCEVHandle OpAtScope = getSCEVAtScope(Comm->getOperand(i), L);
+ const SCEV *OpAtScope = getSCEVAtScope(Comm->getOperand(i), L);
if (OpAtScope != Comm->getOperand(i)) {
- if (OpAtScope == UnknownValue) return UnknownValue;
// Okay, at least one of these operands is loop variant but might be
// foldable. Build a new instance of the folded commutative expression.
- std::vector<SCEVHandle> NewOps(Comm->op_begin(), Comm->op_begin()+i);
+ SmallVector<const SCEV *, 8> NewOps(Comm->op_begin(),
+ Comm->op_begin()+i);
NewOps.push_back(OpAtScope);
for (++i; i != e; ++i) {
OpAtScope = getSCEVAtScope(Comm->getOperand(i), L);
- if (OpAtScope == UnknownValue) return UnknownValue;
NewOps.push_back(OpAtScope);
}
if (isa<SCEVAddExpr>(Comm))
return getSMaxExpr(NewOps);
if (isa<SCEVUMaxExpr>(Comm))
return getUMaxExpr(NewOps);
- assert(0 && "Unknown commutative SCEV type!");
+ llvm_unreachable("Unknown commutative SCEV type!");
}
}
// If we got here, all operands are loop invariant.
return Comm;
}
- if (SCEVUDivExpr *Div = dyn_cast<SCEVUDivExpr>(V)) {
- SCEVHandle LHS = getSCEVAtScope(Div->getLHS(), L);
- if (LHS == UnknownValue) return LHS;
- SCEVHandle RHS = getSCEVAtScope(Div->getRHS(), L);
- if (RHS == UnknownValue) return RHS;
+ if (const SCEVUDivExpr *Div = dyn_cast<SCEVUDivExpr>(V)) {
+ const SCEV *LHS = getSCEVAtScope(Div->getLHS(), L);
+ const SCEV *RHS = getSCEVAtScope(Div->getRHS(), L);
if (LHS == Div->getLHS() && RHS == Div->getRHS())
return Div; // must be loop invariant
return getUDivExpr(LHS, RHS);
// 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 (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {
- if (!L || !AddRec->getLoop()->contains(L->getHeader())) {
+ if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {
+ if (!L || !AddRec->getLoop()->contains(L)) {
// To evaluate this recurrence, we need to know how many times the AddRec
// loop iterates. Compute this now.
- SCEVHandle BackedgeTakenCount = getBackedgeTakenCount(AddRec->getLoop());
- if (BackedgeTakenCount == UnknownValue) return UnknownValue;
+ const SCEV *BackedgeTakenCount = getBackedgeTakenCount(AddRec->getLoop());
+ if (BackedgeTakenCount == getCouldNotCompute()) return AddRec;
// Then, evaluate the AddRec.
return AddRec->evaluateAtIteration(BackedgeTakenCount, *this);
}
- return UnknownValue;
+ return AddRec;
+ }
+
+ if (const SCEVZeroExtendExpr *Cast = dyn_cast<SCEVZeroExtendExpr>(V)) {
+ const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
+ if (Op == Cast->getOperand())
+ return Cast; // must be loop invariant
+ return getZeroExtendExpr(Op, Cast->getType());
}
- //assert(0 && "Unknown SCEV type!");
- return UnknownValue;
+ if (const SCEVSignExtendExpr *Cast = dyn_cast<SCEVSignExtendExpr>(V)) {
+ const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
+ if (Op == Cast->getOperand())
+ return Cast; // must be loop invariant
+ return getSignExtendExpr(Op, Cast->getType());
+ }
+
+ if (const SCEVTruncateExpr *Cast = dyn_cast<SCEVTruncateExpr>(V)) {
+ const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
+ if (Op == Cast->getOperand())
+ return Cast; // must be loop invariant
+ return getTruncateExpr(Op, Cast->getType());
+ }
+
+ llvm_unreachable("Unknown SCEV type!");
+ return 0;
}
-/// getSCEVAtScope - Return a SCEV expression handle 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.
-///
-/// This method can be used to compute the exit value for a variable defined
-/// in a loop by querying what the value will hold in the parent loop.
-///
-/// If this value is not computable at this scope, a SCEVCouldNotCompute
-/// object is returned.
-SCEVHandle ScalarEvolution::getSCEVAtScope(Value *V, const Loop *L) {
+/// getSCEVAtScope - This is a convenience function which does
+/// getSCEVAtScope(getSCEV(V), L).
+const SCEV *ScalarEvolution::getSCEVAtScope(Value *V, const Loop *L) {
return getSCEVAtScope(getSCEV(V), L);
}
/// A and B isn't important.
///
/// If the equation does not have a solution, SCEVCouldNotCompute is returned.
-static SCEVHandle SolveLinEquationWithOverflow(const APInt &A, const APInt &B,
+static const SCEV *SolveLinEquationWithOverflow(const APInt &A, const APInt &B,
ScalarEvolution &SE) {
uint32_t BW = A.getBitWidth();
assert(BW == B.getBitWidth() && "Bit widths must be the same.");
/// given quadratic chrec {L,+,M,+,N}. This returns either the two roots (which
/// might be the same) or two SCEVCouldNotCompute objects.
///
-static std::pair<SCEVHandle,SCEVHandle>
+static std::pair<const SCEV *,const SCEV *>
SolveQuadraticEquation(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) {
assert(AddRec->getNumOperands() == 3 && "This is not a quadratic chrec!");
- SCEVConstant *LC = dyn_cast<SCEVConstant>(AddRec->getOperand(0));
- SCEVConstant *MC = dyn_cast<SCEVConstant>(AddRec->getOperand(1));
- SCEVConstant *NC = dyn_cast<SCEVConstant>(AddRec->getOperand(2));
+ const SCEVConstant *LC = dyn_cast<SCEVConstant>(AddRec->getOperand(0));
+ const SCEVConstant *MC = dyn_cast<SCEVConstant>(AddRec->getOperand(1));
+ const SCEVConstant *NC = dyn_cast<SCEVConstant>(AddRec->getOperand(2));
// We currently can only solve this if the coefficients are constants.
if (!LC || !MC || !NC) {
- SCEV *CNC = SE.getCouldNotCompute();
+ const SCEV *CNC = SE.getCouldNotCompute();
return std::make_pair(CNC, CNC);
}
APInt Two(BitWidth, 2);
APInt Four(BitWidth, 4);
- {
+ {
using namespace APIntOps;
const APInt& C = L;
// Convert from chrec coefficients to polynomial coefficients AX^2+BX+C
// integer value or else APInt::sqrt() will assert.
APInt SqrtVal(SqrtTerm.sqrt());
- // Compute the two solutions for the quadratic formula.
+ // Compute the two solutions for the quadratic formula.
// The divisions must be performed as signed divisions.
APInt NegB(-B);
APInt TwoA( A << 1 );
if (TwoA.isMinValue()) {
- SCEV *CNC = SE.getCouldNotCompute();
+ const SCEV *CNC = SE.getCouldNotCompute();
return std::make_pair(CNC, CNC);
}
- ConstantInt *Solution1 = ConstantInt::get((NegB + SqrtVal).sdiv(TwoA));
- ConstantInt *Solution2 = ConstantInt::get((NegB - SqrtVal).sdiv(TwoA));
+ LLVMContext &Context = SE.getContext();
- return std::make_pair(SE.getConstant(Solution1),
+ ConstantInt *Solution1 =
+ ConstantInt::get(Context, (NegB + SqrtVal).sdiv(TwoA));
+ ConstantInt *Solution2 =
+ ConstantInt::get(Context, (NegB - SqrtVal).sdiv(TwoA));
+
+ return std::make_pair(SE.getConstant(Solution1),
SE.getConstant(Solution2));
} // end APIntOps namespace
}
/// HowFarToZero - Return the number of times a backedge comparing the specified
-/// value to zero will execute. If not computable, return UnknownValue
-SCEVHandle ScalarEvolution::HowFarToZero(SCEV *V, const Loop *L) {
+/// value to zero will execute. If not computable, return CouldNotCompute.
+const SCEV *ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
// If the value is a constant
- if (SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
+ if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
// If the value is already zero, the branch will execute zero times.
if (C->getValue()->isZero()) return C;
- return UnknownValue; // Otherwise it will loop infinitely.
+ return getCouldNotCompute(); // Otherwise it will loop infinitely.
}
- SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V);
+ const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V);
if (!AddRec || AddRec->getLoop() != L)
- return UnknownValue;
+ return getCouldNotCompute();
if (AddRec->isAffine()) {
// If this is an affine expression, the execution count of this branch is
// where BW is the common bit width of Start and Step.
// Get the initial value for the loop.
- SCEVHandle Start = getSCEVAtScope(AddRec->getStart(), L->getParentLoop());
- if (isa<SCEVCouldNotCompute>(Start)) return UnknownValue;
-
- SCEVHandle Step = getSCEVAtScope(AddRec->getOperand(1), L->getParentLoop());
+ const SCEV *Start = getSCEVAtScope(AddRec->getStart(),
+ L->getParentLoop());
+ const SCEV *Step = getSCEVAtScope(AddRec->getOperand(1),
+ L->getParentLoop());
- if (SCEVConstant *StepC = dyn_cast<SCEVConstant>(Step)) {
+ if (const SCEVConstant *StepC = dyn_cast<SCEVConstant>(Step)) {
// For now we handle only constant steps.
// 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)
// Then, try to solve the above equation provided that Start is constant.
- if (SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start))
+ if (const SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start))
return SolveLinEquationWithOverflow(StepC->getValue()->getValue(),
-StartC->getValue()->getValue(),
*this);
} else if (AddRec->isQuadratic() && AddRec->getType()->isInteger()) {
// If this is a quadratic (3-term) AddRec {L,+,M,+,N}, find the roots of
// the quadratic equation to solve it.
- std::pair<SCEVHandle,SCEVHandle> Roots = SolveQuadraticEquation(AddRec,
+ std::pair<const SCEV *,const SCEV *> Roots = SolveQuadraticEquation(AddRec,
*this);
- SCEVConstant *R1 = dyn_cast<SCEVConstant>(Roots.first);
- SCEVConstant *R2 = dyn_cast<SCEVConstant>(Roots.second);
+ const SCEVConstant *R1 = dyn_cast<SCEVConstant>(Roots.first);
+ 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.
if (ConstantInt *CB =
- dyn_cast<ConstantInt>(ConstantExpr::getICmp(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.
// We can only use this value if the chrec ends up with an exact zero
// value at this index. When solving for "X*X != 5", for example, we
// should not accept a root of 2.
- SCEVHandle Val = AddRec->evaluateAtIteration(R1, *this);
+ const SCEV *Val = AddRec->evaluateAtIteration(R1, *this);
if (Val->isZero())
return R1; // We found a quadratic root!
}
}
}
- return UnknownValue;
+ return getCouldNotCompute();
}
/// HowFarToNonZero - Return the number of times a backedge checking the
/// specified value for nonzero will execute. If not computable, return
-/// UnknownValue
-SCEVHandle ScalarEvolution::HowFarToNonZero(SCEV *V, const Loop *L) {
+/// CouldNotCompute
+const SCEV *ScalarEvolution::HowFarToNonZero(const SCEV *V, const Loop *L) {
// Loops that look like: while (X == 0) are very strange indeed. We don't
// handle them yet except for the trivial case. This could be expanded in the
// future as needed.
// If the value is a constant, check to see if it is known to be non-zero
// already. If so, the backedge will execute zero times.
- if (SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
+ if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
if (!C->getValue()->isNullValue())
return getIntegerSCEV(0, C->getType());
- return UnknownValue; // Otherwise it will loop infinitely.
+ return getCouldNotCompute(); // Otherwise it will loop infinitely.
}
// We could implement others, but I really doubt anyone writes loops like
// this, and if they did, they would already be constant folded.
- return UnknownValue;
+ return getCouldNotCompute();
+}
+
+/// getLoopPredecessor - If the given loop's header has exactly one unique
+/// predecessor outside the loop, return it. Otherwise return null.
+///
+BasicBlock *ScalarEvolution::getLoopPredecessor(const Loop *L) {
+ BasicBlock *Header = L->getHeader();
+ BasicBlock *Pred = 0;
+ for (pred_iterator PI = pred_begin(Header), E = pred_end(Header);
+ PI != E; ++PI)
+ if (!L->contains(*PI)) {
+ if (Pred && Pred != *PI) return 0; // Multiple predecessors.
+ Pred = *PI;
+ }
+ return Pred;
}
/// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
///
BasicBlock *
ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB) {
- // If the block has a unique predecessor, the predecessor must have
- // no other successors from which BB is reachable.
+ // If the block has a unique predecessor, then there is no path from the
+ // predecessor to the block that does not go through the direct edge
+ // from the predecessor to the block.
if (BasicBlock *Pred = BB->getSinglePredecessor())
return Pred;
// A loop's header is defined to be a block that dominates the loop.
- // If the loop has a preheader, it must be a block that has exactly
- // one successor that can reach BB. This is slightly more strict
- // than necessary, but works if critical edges are split.
+ // If the header has a unique predecessor outside the loop, it must be
+ // a block that has exactly one successor that can reach the loop.
if (Loop *L = LI->getLoopFor(BB))
- return L->getLoopPreheader();
+ return getLoopPredecessor(L);
return 0;
}
-/// isLoopGuardedByCond - Test whether entry to the loop is protected by
-/// a conditional between LHS and RHS.
-bool ScalarEvolution::isLoopGuardedByCond(const Loop *L,
- ICmpInst::Predicate Pred,
- SCEV *LHS, SCEV *RHS) {
- BasicBlock *Preheader = L->getLoopPreheader();
- BasicBlock *PreheaderDest = L->getHeader();
+/// HasSameValue - SCEV structural equivalence is usually sufficient for
+/// testing whether two expressions are equal, however for the purposes of
+/// looking for a condition guarding a loop, it can be useful to be a little
+/// more general, since a front-end may have replicated the controlling
+/// expression.
+///
+static bool HasSameValue(const SCEV *A, const SCEV *B) {
+ // Quick check to see if they are the same SCEV.
+ if (A == B) return true;
+
+ // Otherwise, if they're both SCEVUnknown, it's possible that they hold
+ // two different instructions with the same value. Check for this case.
+ if (const SCEVUnknown *AU = dyn_cast<SCEVUnknown>(A))
+ 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) && !AI->mayReadFromMemory())
+ return true;
+
+ // Otherwise assume they may have a different value.
+ return false;
+}
+
+bool ScalarEvolution::isKnownNegative(const SCEV *S) {
+ return getSignedRange(S).getSignedMax().isNegative();
+}
+
+bool ScalarEvolution::isKnownPositive(const SCEV *S) {
+ return getSignedRange(S).getSignedMin().isStrictlyPositive();
+}
+
+bool ScalarEvolution::isKnownNonNegative(const SCEV *S) {
+ return !getSignedRange(S).getSignedMin().isNegative();
+}
+
+bool ScalarEvolution::isKnownNonPositive(const SCEV *S) {
+ return !getSignedRange(S).getSignedMax().isStrictlyPositive();
+}
+
+bool ScalarEvolution::isKnownNonZero(const SCEV *S) {
+ return isKnownNegative(S) || isKnownPositive(S);
+}
+
+bool ScalarEvolution::isKnownPredicate(ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS) {
+
+ if (HasSameValue(LHS, RHS))
+ return ICmpInst::isTrueWhenEqual(Pred);
+
+ switch (Pred) {
+ default:
+ llvm_unreachable("Unexpected ICmpInst::Predicate value!");
+ break;
+ case ICmpInst::ICMP_SGT:
+ Pred = ICmpInst::ICMP_SLT;
+ std::swap(LHS, RHS);
+ case ICmpInst::ICMP_SLT: {
+ ConstantRange LHSRange = getSignedRange(LHS);
+ ConstantRange RHSRange = getSignedRange(RHS);
+ if (LHSRange.getSignedMax().slt(RHSRange.getSignedMin()))
+ return true;
+ if (LHSRange.getSignedMin().sge(RHSRange.getSignedMax()))
+ return false;
+ break;
+ }
+ case ICmpInst::ICMP_SGE:
+ Pred = ICmpInst::ICMP_SLE;
+ std::swap(LHS, RHS);
+ case ICmpInst::ICMP_SLE: {
+ ConstantRange LHSRange = getSignedRange(LHS);
+ ConstantRange RHSRange = getSignedRange(RHS);
+ if (LHSRange.getSignedMax().sle(RHSRange.getSignedMin()))
+ return true;
+ if (LHSRange.getSignedMin().sgt(RHSRange.getSignedMax()))
+ return false;
+ break;
+ }
+ case ICmpInst::ICMP_UGT:
+ Pred = ICmpInst::ICMP_ULT;
+ std::swap(LHS, RHS);
+ case ICmpInst::ICMP_ULT: {
+ ConstantRange LHSRange = getUnsignedRange(LHS);
+ ConstantRange RHSRange = getUnsignedRange(RHS);
+ if (LHSRange.getUnsignedMax().ult(RHSRange.getUnsignedMin()))
+ return true;
+ if (LHSRange.getUnsignedMin().uge(RHSRange.getUnsignedMax()))
+ return false;
+ break;
+ }
+ case ICmpInst::ICMP_UGE:
+ Pred = ICmpInst::ICMP_ULE;
+ std::swap(LHS, RHS);
+ case ICmpInst::ICMP_ULE: {
+ ConstantRange LHSRange = getUnsignedRange(LHS);
+ ConstantRange RHSRange = getUnsignedRange(RHS);
+ if (LHSRange.getUnsignedMax().ule(RHSRange.getUnsignedMin()))
+ return true;
+ if (LHSRange.getUnsignedMin().ugt(RHSRange.getUnsignedMax()))
+ return false;
+ break;
+ }
+ case ICmpInst::ICMP_NE: {
+ if (getUnsignedRange(LHS).intersectWith(getUnsignedRange(RHS)).isEmptySet())
+ return true;
+ if (getSignedRange(LHS).intersectWith(getSignedRange(RHS)).isEmptySet())
+ return true;
+
+ const SCEV *Diff = getMinusSCEV(LHS, RHS);
+ if (isKnownNonZero(Diff))
+ return true;
+ 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;
+}
+
+/// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
+/// protected by a conditional between LHS and RHS. This is used to
+/// to eliminate casts.
+bool
+ScalarEvolution::isLoopBackedgeGuardedByCond(const Loop *L,
+ ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS) {
+ // Interpret a null as meaning no loop, where there is obviously no guard
+ // (interprocedural conditions notwithstanding).
+ if (!L) return true;
+
+ BasicBlock *Latch = L->getLoopLatch();
+ if (!Latch)
+ return false;
+
+ BranchInst *LoopContinuePredicate =
+ dyn_cast<BranchInst>(Latch->getTerminator());
+ if (!LoopContinuePredicate ||
+ LoopContinuePredicate->isUnconditional())
+ return false;
+
+ return isImpliedCond(LoopContinuePredicate->getCondition(), Pred, LHS, RHS,
+ LoopContinuePredicate->getSuccessor(0) != L->getHeader());
+}
- // Starting at the preheader, climb up the predecessor chain, as long as
- // there are predecessors that can be found that have unique successors
+/// isLoopGuardedByCond - Test whether entry to the loop is protected
+/// by a conditional between LHS and RHS. This is used to help avoid max
+/// expressions in loop trip counts, and to eliminate casts.
+bool
+ScalarEvolution::isLoopGuardedByCond(const Loop *L,
+ ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS) {
+ // Interpret a null as meaning no loop, where there is obviously no guard
+ // (interprocedural conditions notwithstanding).
+ if (!L) return false;
+
+ BasicBlock *Predecessor = getLoopPredecessor(L);
+ BasicBlock *PredecessorDest = L->getHeader();
+
+ // Starting at the loop predecessor, climb up the predecessor chain, as long
+ // as there are predecessors that can be found that have unique successors
// leading to the original header.
- for (; Preheader;
- PreheaderDest = Preheader,
- Preheader = getPredecessorWithUniqueSuccessorForBB(Preheader)) {
+ for (; Predecessor;
+ PredecessorDest = Predecessor,
+ Predecessor = getPredecessorWithUniqueSuccessorForBB(Predecessor)) {
BranchInst *LoopEntryPredicate =
- dyn_cast<BranchInst>(Preheader->getTerminator());
+ dyn_cast<BranchInst>(Predecessor->getTerminator());
if (!LoopEntryPredicate ||
LoopEntryPredicate->isUnconditional())
continue;
- ICmpInst *ICI = dyn_cast<ICmpInst>(LoopEntryPredicate->getCondition());
- if (!ICI) continue;
+ if (isImpliedCond(LoopEntryPredicate->getCondition(), Pred, LHS, RHS,
+ LoopEntryPredicate->getSuccessor(0) != PredecessorDest))
+ return true;
+ }
- // 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 Cond;
- if (LoopEntryPredicate->getSuccessor(0) == PreheaderDest)
- Cond = ICI->getPredicate();
- else
- Cond = ICI->getInversePredicate();
+ return false;
+}
- if (Cond == Pred)
- ; // An exact match.
- else if (!ICmpInst::isTrueWhenEqual(Cond) && Pred == ICmpInst::ICMP_NE)
- ; // The actual condition is beyond sufficient.
- else
- // Check a few special cases.
- switch (Cond) {
- case ICmpInst::ICMP_UGT:
- if (Pred == ICmpInst::ICMP_ULT) {
- std::swap(PreCondLHS, PreCondRHS);
- Cond = ICmpInst::ICMP_ULT;
- break;
- }
- continue;
- case ICmpInst::ICMP_SGT:
- if (Pred == ICmpInst::ICMP_SLT) {
- std::swap(PreCondLHS, PreCondRHS);
- Cond = ICmpInst::ICMP_SLT;
- break;
- }
- continue;
- 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 (ConstantInt *CI = dyn_cast<ConstantInt>(PreCondRHS)) {
- const APInt &A = CI->getValue();
- switch (Pred) {
- case ICmpInst::ICMP_SLT:
- if (A.isMaxSignedValue()) break;
- continue;
- case ICmpInst::ICMP_SGT:
- if (A.isMinSignedValue()) break;
- continue;
- case ICmpInst::ICMP_ULT:
- if (A.isMaxValue()) break;
- continue;
- case ICmpInst::ICMP_UGT:
- if (A.isMinValue()) break;
- continue;
- default:
- continue;
- }
- Cond = 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);
- break;
- }
- continue;
- default:
- // We weren't able to reconcile the condition.
- continue;
+/// 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 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 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;
+
+ // 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(ICI->getOperand(0)->getType()))
+ 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.
+ 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.
+ if (getTypeSizeInBits(LHS->getType()) >
+ getTypeSizeInBits(FoundLHS->getType())) {
+ if (CmpInst::isSigned(Pred)) {
+ FoundLHS = getSignExtendExpr(FoundLHS, LHS->getType());
+ FoundRHS = getSignExtendExpr(FoundRHS, LHS->getType());
+ } else {
+ FoundLHS = getZeroExtendExpr(FoundLHS, LHS->getType());
+ FoundRHS = getZeroExtendExpr(FoundRHS, LHS->getType());
+ }
+ }
+
+ // 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;
+}
- if (!PreCondLHS->getType()->isInteger()) continue;
+/// 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
+ isImpliedCondOperandsHelper(Pred, LHS, RHS,
+ getNotSCEV(FoundRHS),
+ getNotSCEV(FoundLHS));
+}
- SCEVHandle PreCondLHSSCEV = getSCEV(PreCondLHS);
- SCEVHandle PreCondRHSSCEV = getSCEV(PreCondRHS);
- if ((LHS == PreCondLHSSCEV && RHS == PreCondRHSSCEV) ||
- (LHS == getNotSCEV(PreCondRHSSCEV) &&
- RHS == getNotSCEV(PreCondLHSSCEV)))
+/// 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::isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ const SCEV *FoundLHS,
+ const SCEV *FoundRHS) {
+ switch (Pred) {
+ 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;
+ break;
}
return false;
}
+/// getBECount - Subtract the end and start values and divide by the step,
+/// rounding up, to get the number of times the backedge is executed. Return
+/// CouldNotCompute if an intermediate computation overflows.
+const SCEV *ScalarEvolution::getBECount(const SCEV *Start,
+ const SCEV *End,
+ 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);
+ const SCEV *RoundUp = getAddExpr(Step, NegOne);
+
+ // Add an adjustment to the difference between End and Start so that
+ // the division will effectively round up.
+ const SCEV *Add = getAddExpr(Diff, RoundUp);
+
+ 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);
+}
+
/// HowManyLessThans - Return the number of times a backedge containing the
/// specified less-than comparison will execute. If not computable, return
-/// UnknownValue.
-SCEVHandle ScalarEvolution::
-HowManyLessThans(SCEV *LHS, SCEV *RHS, const Loop *L, bool isSigned) {
+/// CouldNotCompute.
+ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
+ const Loop *L, bool isSigned) {
// Only handle: "ADDREC < LoopInvariant".
- if (!RHS->isLoopInvariant(L)) return UnknownValue;
+ if (!RHS->isLoopInvariant(L)) return getCouldNotCompute();
- SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS);
+ const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS);
if (!AddRec || AddRec->getLoop() != L)
- return UnknownValue;
+ 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.
- SCEVHandle One = getIntegerSCEV(1, RHS->getType());
- if (AddRec->getOperand(1) != One)
- return UnknownValue;
-
- // We know the LHS is of the form {n,+,1} and the RHS is some loop-invariant
- // m. So, we count the number of iterations in which {n,+,1} < m is true.
- // Note that we cannot simply return max(m-n,0) because it's not safe to
+ unsigned BitWidth = getTypeSizeInBits(AddRec->getType());
+ const SCEV *Step = AddRec->getStepRecurrence(*this);
+
+ if (Step->isZero())
+ return getCouldNotCompute();
+ if (Step->isOne()) {
+ // With unit stride, the iteration never steps past the limit value.
+ } 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 here and below.
+ return getCouldNotCompute();
+
+ // We know the LHS is of the form {n,+,s} and the RHS is some loop-invariant
+ // m. So, we count the number of iterations in which {n,+,s} < m is true.
+ // Note that we cannot simply return max(m-n,0)/s because it's not safe to
// treat m-n as signed nor unsigned due to overflow possibility.
// First, we get the value of the LHS in the first iteration: n
- SCEVHandle Start = AddRec->getOperand(0);
-
- if (isLoopGuardedByCond(L,
- isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
- getMinusSCEV(AddRec->getOperand(0), One), RHS)) {
- // Since we know that the condition is true in order to enter the loop,
- // we know that it will run exactly m-n times.
- return getMinusSCEV(RHS, Start);
- } else {
- // Then, we get the value of the LHS in the first iteration in which the
- // above condition doesn't hold. This equals to max(m,n).
- SCEVHandle End = isSigned ? getSMaxExpr(RHS, Start)
- : getUMaxExpr(RHS, Start);
-
- // Finally, we subtract these two values to get the number of times the
- // backedge is executed: max(m,n)-n.
- return getMinusSCEV(End, Start);
- }
+ const SCEV *Start = AddRec->getOperand(0);
+
+ // Determine the minimum constant start value.
+ const SCEV *MinStart = getConstant(isSigned ?
+ getSignedRange(Start).getSignedMin() :
+ getUnsignedRange(Start).getUnsignedMin());
+
+ // If we know that the condition is true in order to enter the loop,
+ // then we know that it will run exactly (m-n)/s times. Otherwise, we
+ // only know that it will execute (max(m,n)-n)/s times. In both cases,
+ // the division must round up.
+ const SCEV *End = RHS;
+ if (!isLoopGuardedByCond(L,
+ isSigned ? ICmpInst::ICMP_SLT :
+ ICmpInst::ICMP_ULT,
+ getMinusSCEV(Start, Step), RHS))
+ End = isSigned ? getSMaxExpr(RHS, Start)
+ : getUMaxExpr(RHS, Start);
+
+ // Determine the maximum constant end value.
+ const SCEV *MaxEnd = getConstant(isSigned ?
+ 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, 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, NoWrap);
+
+ return BackedgeTakenInfo(BECount, MaxBECount);
}
- return UnknownValue;
+ return getCouldNotCompute();
}
/// getNumIterationsInRange - Return the number of iterations of this loop that
/// this is that it returns the first iteration number where the value is not in
/// the condition, thus computing the exit count. If the iteration count can't
/// be computed, an instance of SCEVCouldNotCompute is returned.
-SCEVHandle SCEVAddRecExpr::getNumIterationsInRange(ConstantRange Range,
- ScalarEvolution &SE) const {
+const SCEV *SCEVAddRecExpr::getNumIterationsInRange(ConstantRange Range,
+ ScalarEvolution &SE) const {
if (Range.isFullSet()) // Infinite loop.
return SE.getCouldNotCompute();
// If the start is a non-zero constant, shift the range to simplify things.
- if (SCEVConstant *SC = dyn_cast<SCEVConstant>(getStart()))
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(getStart()))
if (!SC->getValue()->isZero()) {
- std::vector<SCEVHandle> Operands(op_begin(), op_end());
+ SmallVector<const SCEV *, 4> Operands(op_begin(), op_end());
Operands[0] = SE.getIntegerSCEV(0, SC->getType());
- SCEVHandle Shifted = SE.getAddRecExpr(Operands, getLoop());
- if (SCEVAddRecExpr *ShiftedAddRec = dyn_cast<SCEVAddRecExpr>(Shifted))
+ const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop());
+ if (const SCEVAddRecExpr *ShiftedAddRec =
+ dyn_cast<SCEVAddRecExpr>(Shifted))
return ShiftedAddRec->getNumIterationsInRange(
Range.subtract(SC->getValue()->getValue()), SE);
// This is strange and shouldn't happen.
// iteration exits.
unsigned BitWidth = SE.getTypeSizeInBits(getType());
if (!Range.contains(APInt(BitWidth, 0)))
- return SE.getConstant(ConstantInt::get(getType(),0));
+ return SE.getIntegerSCEV(0, getType());
if (isAffine()) {
// If this is an affine expression then we have this situation:
// The exit value should be (End+A)/A.
APInt ExitVal = (End + A).udiv(A);
- ConstantInt *ExitValue = ConstantInt::get(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,
- ConstantInt::get(ExitVal - One), SE)->getValue()) &&
+ EvaluateConstantChrecAtConstant(this,
+ ConstantInt::get(SE.getContext(), ExitVal - One), SE)->getValue()) &&
"Linear scev computation is off in a bad way!");
return SE.getConstant(ExitValue);
} else if (isQuadratic()) {
// quadratic equation to solve it. To do this, we must frame our problem in
// terms of figuring out when zero is crossed, instead of when
// Range.getUpper() is crossed.
- std::vector<SCEVHandle> NewOps(op_begin(), op_end());
+ SmallVector<const SCEV *, 4> NewOps(op_begin(), op_end());
NewOps[0] = SE.getNegativeSCEV(SE.getConstant(Range.getUpper()));
- SCEVHandle NewAddRec = SE.getAddRecExpr(NewOps, getLoop());
+ const SCEV *NewAddRec = SE.getAddRecExpr(NewOps, getLoop());
// Next, solve the constructed addrec
- std::pair<SCEVHandle,SCEVHandle> Roots =
+ std::pair<const SCEV *,const SCEV *> Roots =
SolveQuadraticEquation(cast<SCEVAddRecExpr>(NewAddRec), SE);
- SCEVConstant *R1 = dyn_cast<SCEVConstant>(Roots.first);
- SCEVConstant *R2 = dyn_cast<SCEVConstant>(Roots.second);
+ const SCEVConstant *R1 = dyn_cast<SCEVConstant>(Roots.first);
+ const SCEVConstant *R2 = dyn_cast<SCEVConstant>(Roots.second);
if (R1) {
// Pick the smallest positive root value.
if (ConstantInt *CB =
- dyn_cast<ConstantInt>(ConstantExpr::getICmp(ICmpInst::ICMP_ULT,
- R1->getValue(), R2->getValue()))) {
+ 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.
SE);
if (Range.contains(R1Val->getValue())) {
// The next iteration must be out of the range...
- ConstantInt *NextVal = ConstantInt::get(R1->getValue()->getValue()+1);
+ ConstantInt *NextVal =
+ 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 = ConstantInt::get(R1->getValue()->getValue()-1);
+ ConstantInt *NextVal =
+ ConstantInt::get(SE.getContext(), R1->getValue()->getValue()-1);
R1Val = EvaluateConstantChrecAtConstant(this, NextVal, SE);
if (Range.contains(R1Val->getValue()))
return R1;
+//===----------------------------------------------------------------------===//
+// SCEVCallbackVH Class Implementation
+//===----------------------------------------------------------------------===//
+
+void ScalarEvolution::SCEVCallbackVH::deleted() {
+ assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!");
+ if (PHINode *PN = dyn_cast<PHINode>(getValPtr()))
+ SE->ConstantEvolutionLoopExitValue.erase(PN);
+ SE->Scalars.erase(getValPtr());
+ // this now dangles!
+}
+
+void ScalarEvolution::SCEVCallbackVH::allUsesReplacedWith(Value *) {
+ assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!");
+
+ // Forget all the expressions associated with users of the old value,
+ // 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();
+ UI != UE; ++UI)
+ Worklist.push_back(*UI);
+ while (!Worklist.empty()) {
+ User *U = Worklist.pop_back_val();
+ // Deleting the Old value will cause this to dangle. Postpone
+ // that until everything else is done.
+ if (U == Old) {
+ DeleteOld = true;
+ continue;
+ }
+ if (!Visited.insert(U))
+ continue;
+ if (PHINode *PN = dyn_cast<PHINode>(U))
+ SE->ConstantEvolutionLoopExitValue.erase(PN);
+ 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);
+ SE->Scalars.erase(Old);
+ // this now dangles!
+ }
+ // this may dangle!
+}
+
+ScalarEvolution::SCEVCallbackVH::SCEVCallbackVH(Value *V, ScalarEvolution *se)
+ : CallbackVH(V), SE(se) {}
+
//===----------------------------------------------------------------------===//
// ScalarEvolution Class Implementation
//===----------------------------------------------------------------------===//
ScalarEvolution::ScalarEvolution()
- : FunctionPass(&ID), UnknownValue(new SCEVCouldNotCompute()) {
+ : FunctionPass(&ID) {
}
bool ScalarEvolution::runOnFunction(Function &F) {
this->F = &F;
LI = &getAnalysis<LoopInfo>();
+ DT = &getAnalysis<DominatorTree>();
TD = getAnalysisIfAvailable<TargetData>();
return false;
}
Scalars.clear();
BackedgeTakenCounts.clear();
ConstantEvolutionLoopExitValue.clear();
+ ValuesAtScopes.clear();
+ UniqueSCEVs.clear();
+ SCEVAllocator.Reset();
}
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"
+ "Loop ";
+ WriteAsOperand(OS, L->getHeader(), /*PrintType=*/false);
+ OS << ": ";
+
+ if (!isa<SCEVCouldNotCompute>(SE->getMaxBackedgeTakenCount(L))) {
+ OS << "max backedge-taken count is " << *SE->getMaxBackedgeTakenCount(L);
+ } else {
+ OS << "Unpredictable max backedge-taken count. ";
+ }
+
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 (the hasSCEV function
- // notwithstanding), so casting away the const isn't dangerous.
- ScalarEvolution &SE = *const_cast<ScalarEvolution*>(this);
+ // observable from outside the class though, so casting away the
+ // const isn't dangerous.
+ 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 (I->getType()->isInteger()) {
- OS << *I;
+ if (isSCEVable(I->getType())) {
+ OS << *I << '\n';
OS << " --> ";
- SCEVHandle SV = SE.getSCEV(&*I);
+ const SCEV *SV = SE.getSCEV(&*I);
SV->print(OS);
- OS << "\t\t";
- if (const Loop *L = LI->getLoopFor((*I).getParent())) {
- OS << "Exits: ";
- SCEVHandle ExitValue = SE.getSCEVAtScope(&*I, L->getParentLoop());
- if (isa<SCEVCouldNotCompute>(ExitValue)) {
+ const Loop *L = LI->getLoopFor((*I).getParent());
+
+ const SCEV *AtUse = SE.getSCEVAtScope(SV, L);
+ if (AtUse != SV) {
+ OS << " --> ";
+ AtUse->print(OS);
+ }
+
+ if (L) {
+ OS << "\t\t" "Exits: ";
+ const SCEV *ExitValue = SE.getSCEVAtScope(SV, L->getParentLoop());
+ if (!ExitValue->isLoopInvariant(L)) {
OS << "<<Unknown>>";
} else {
OS << *ExitValue;
}
}
-
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);
}
-void ScalarEvolution::print(std::ostream &o, const Module *M) const {
- raw_os_ostream OS(o);
- print(OS, M);
-}
projects / oota-llvm.git / blobdiff