6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-08-02 09:29:24 +00:00
Code Issues Projects Releases Wiki Activity

Generalize ScalarEvolution to be able to analyze GEPs when

Browse Source 
TargetData is not present. It still uses TargetData when available.
This generalization also fixed some limitations in the TargetData
case; the attached testcase covers this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79344 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-08-18 16:46:41 +00:00
parent 4d35fce60c
commit c40f17b087
6 changed files with 566 additions and 122 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/llvm/Analysis/ScalarEvolution.h
View File

@ -433,6 +433,8 @@ namespace llvm {
const SCEV *getUMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
const SCEV *getSMinExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getUMinExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getFieldOffsetExpr(const StructType *STy, unsigned FieldNo);
const SCEV *getAllocSizeExpr(const Type *AllocTy);
const SCEV *getUnknown(Value *V);
const SCEV *getCouldNotCompute();

4
include/llvm/Analysis/ScalarEvolutionExpander.h
View File

@ -115,6 +115,10 @@ namespace llvm {
Value *visitUMaxExpr(const SCEVUMaxExpr *S);
Value *visitFieldOffsetExpr(const SCEVFieldOffsetExpr *S);
Value *visitAllocSizeExpr(const SCEVAllocSizeExpr *S);
Value *visitUnknown(const SCEVUnknown *S) {
return S->getValue();
}

92
include/llvm/Analysis/ScalarEvolutionExpressions.h
View File

@ -26,8 +26,8 @@ namespace llvm {
// These should be ordered in terms of increasing complexity to make the
// folders simpler.
scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr,
scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr, scUnknown,
scCouldNotCompute
scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr,
scFieldOffset, scAllocSize, scUnknown, scCouldNotCompute
};
//===--------------------------------------------------------------------===//
@ -488,6 +488,90 @@ namespace llvm {
}
};
//===--------------------------------------------------------------------===//
/// SCEVTargetDataConstant - This node is the base class for representing
/// target-dependent values in a target-independent way.
///
class SCEVTargetDataConstant : public SCEV {
protected:
const Type *Ty;
SCEVTargetDataConstant(const FoldingSetNodeID &ID, enum SCEVTypes T,
const Type *ty) :
SCEV(ID, T), Ty(ty) {}
public:
virtual bool isLoopInvariant(const Loop *) const { return true; }
virtual bool hasComputableLoopEvolution(const Loop *) const {
return false; // not computable
}
virtual bool hasOperand(const SCEV *) const {
return false;
}
bool dominates(BasicBlock *, DominatorTree *) const {
return true;
}
virtual const Type *getType() const { return Ty; }
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVTargetDataConstant *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scFieldOffset ||
S->getSCEVType() == scAllocSize;
}
};
//===--------------------------------------------------------------------===//
/// SCEVFieldOffsetExpr - This node represents an offsetof expression.
///
class SCEVFieldOffsetExpr : public SCEVTargetDataConstant {
friend class ScalarEvolution;
const StructType *STy;
unsigned FieldNo;
SCEVFieldOffsetExpr(const FoldingSetNodeID &ID, const Type *ty,
const StructType *sty, unsigned fieldno) :
SCEVTargetDataConstant(ID, scFieldOffset, ty),
STy(sty), FieldNo(fieldno) {}
public:
const StructType *getStructType() const { return STy; }
unsigned getFieldNo() const { return FieldNo; }
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVFieldOffsetExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scFieldOffset;
}
};
//===--------------------------------------------------------------------===//
/// SCEVAllocSize - This node represents a sizeof expression.
///
class SCEVAllocSizeExpr : public SCEVTargetDataConstant {
friend class ScalarEvolution;
const Type *AllocTy;
SCEVAllocSizeExpr(const FoldingSetNodeID &ID,
const Type *ty, const Type *allocty) :
SCEVTargetDataConstant(ID, scAllocSize, ty),
AllocTy(allocty) {}
public:
const Type *getAllocType() const { return AllocTy; }
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVAllocSizeExpr *S) { return true; }
static inline bool classof(const SCEV *S) {
return S->getSCEVType() == scAllocSize;
}
};
//===--------------------------------------------------------------------===//
/// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
@ -552,6 +636,10 @@ namespace llvm {
return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
case scUMaxExpr:
return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
case scFieldOffset:
return ((SC*)this)->visitFieldOffsetExpr((const SCEVFieldOffsetExpr*)S);
case scAllocSize:
return ((SC*)this)->visitAllocSizeExpr((const SCEVAllocSizeExpr*)S);
case scUnknown:
return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
case scCouldNotCompute:

200
lib/Analysis/ScalarEvolution.cpp
View File

@ -307,6 +307,15 @@ void SCEVAddRecExpr::print(raw_ostream &OS) const {
OS << "}<" << L->getHeader()->getName() + ">";
}
void SCEVFieldOffsetExpr::print(raw_ostream &OS) const {
// LLVM struct fields don't have names, so just print the field number.
OS << "offsetof(" << *STy << ", " << FieldNo << ")";
}
void SCEVAllocSizeExpr::print(raw_ostream &OS) const {
OS << "sizeof(" << *AllocTy << ")";
}
bool SCEVUnknown::isLoopInvariant(const Loop *L) const {
// All non-instruction values are loop invariant. All instructions are loop
// invariant if they are not contained in the specified loop.
@ -335,6 +344,41 @@ void SCEVUnknown::print(raw_ostream &OS) const {
// 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
@ -447,6 +491,21 @@ namespace {
return operator()(LC->getOperand(), RC->getOperand());
}
// Compare offsetof expressions.
if (const SCEVFieldOffsetExpr *LA = dyn_cast<SCEVFieldOffsetExpr>(LHS)) {
const SCEVFieldOffsetExpr *RA = cast<SCEVFieldOffsetExpr>(RHS);
if (CompareTypes(LA->getStructType(), RA->getStructType()) ||
CompareTypes(RA->getStructType(), LA->getStructType()))
return CompareTypes(LA->getStructType(), RA->getStructType());
return LA->getFieldNo() < RA->getFieldNo();
}
// Compare sizeof expressions by the allocation type.
if (const SCEVAllocSizeExpr *LA = dyn_cast<SCEVAllocSizeExpr>(LHS)) {
const SCEVAllocSizeExpr *RA = cast<SCEVAllocSizeExpr>(RHS);
return CompareTypes(LA->getAllocType(), RA->getAllocType());
}
llvm_unreachable("Unknown SCEV kind!");
return false;
}
@ -976,7 +1035,7 @@ const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op,
/// unspecified bits out to the given type.
///
const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op,
const Type *Ty) {
const Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
"This is not an extending conversion!");
assert(isSCEVable(Ty) &&
@ -2001,6 +2060,76 @@ const SCEV *ScalarEvolution::getUMinExpr(const SCEV *LHS,
return getNotSCEV(getUMaxExpr(getNotSCEV(LHS), getNotSCEV(RHS)));
}
const SCEV *ScalarEvolution::getFieldOffsetExpr(const StructType *STy,
unsigned FieldNo) {
// If we have TargetData we can determine the constant offset.
if (TD) {
const Type *IntPtrTy = TD->getIntPtrType(getContext());
const StructLayout &SL = *TD->getStructLayout(STy);
uint64_t Offset = SL.getElementOffset(FieldNo);
return getIntegerSCEV(Offset, IntPtrTy);
}
// Field 0 is always at offset 0.
if (FieldNo == 0) {
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
return getIntegerSCEV(0, Ty);
}
// Okay, it looks like we really DO need an offsetof expr. Check to see if we
// already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scFieldOffset);
ID.AddPointer(STy);
ID.AddInteger(FieldNo);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = SCEVAllocator.Allocate<SCEVFieldOffsetExpr>();
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
new (S) SCEVFieldOffsetExpr(ID, Ty, STy, FieldNo);
UniqueSCEVs.InsertNode(S, IP);
return S;
}
const SCEV *ScalarEvolution::getAllocSizeExpr(const Type *AllocTy) {
// If we have TargetData we can determine the constant size.
if (TD && AllocTy->isSized()) {
const Type *IntPtrTy = TD->getIntPtrType(getContext());
return getIntegerSCEV(TD->getTypeAllocSize(AllocTy), IntPtrTy);
}
// Expand an array size into the element size times the number
// of elements.
if (const ArrayType *ATy = dyn_cast<ArrayType>(AllocTy)) {
const SCEV *E = getAllocSizeExpr(ATy->getElementType());
return getMulExpr(
E, getConstant(ConstantInt::get(cast<IntegerType>(E->getType()),
ATy->getNumElements())));
}
// Expand a vector size into the element size times the number
// of elements.
if (const VectorType *VTy = dyn_cast<VectorType>(AllocTy)) {
const SCEV *E = getAllocSizeExpr(VTy->getElementType());
return getMulExpr(
E, getConstant(ConstantInt::get(cast<IntegerType>(E->getType()),
VTy->getNumElements())));
}
// Okay, it looks like we really DO need a sizeof expr. Check to see if we
// already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scAllocSize);
ID.AddPointer(AllocTy);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = SCEVAllocator.Allocate<SCEVAllocSizeExpr>();
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
new (S) SCEVAllocSizeExpr(ID, Ty, AllocTy);
UniqueSCEVs.InsertNode(S, IP);
return S;
}
const SCEV *ScalarEvolution::getUnknown(Value *V) {
// Don't attempt to do anything other than create a SCEVUnknown object
// here. createSCEV only calls getUnknown after checking for all other
@ -2027,17 +2156,8 @@ const SCEV *ScalarEvolution::getUnknown(Value *V) {
/// 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,
@ -2049,9 +2169,14 @@ uint64_t ScalarEvolution::getTypeSizeInBits(const Type *Ty) const {
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
@ -2064,8 +2189,12 @@ const Type *ScalarEvolution::getEffectiveSCEVType(const Type *Ty) const {
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(getContext());
if (TD) return TD->getIntPtrType(getContext());
// Without TargetData, conservatively assume pointers are 64-bit.
return Type::getInt64Ty(getContext());
}
const SCEV *ScalarEvolution::getCouldNotCompute() {
@ -2132,8 +2261,8 @@ 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
@ -2149,8 +2278,8 @@ 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
@ -2165,8 +2294,8 @@ ScalarEvolution::getTruncateOrSignExtend(const SCEV *V,
const SCEV *
ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
(Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot noop or zero extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrZeroExtend cannot truncate!");
@ -2181,8 +2310,8 @@ ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, const Type *Ty) {
const SCEV *
ScalarEvolution::getNoopOrSignExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
(Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot noop or sign extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrSignExtend cannot truncate!");
@ -2198,8 +2327,8 @@ ScalarEvolution::getNoopOrSignExtend(const SCEV *V, const Type *Ty) {
const SCEV *
ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
(Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot noop or any extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrAnyExtend cannot truncate!");
@ -2213,8 +2342,8 @@ ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, const Type *Ty) {
const SCEV *
ScalarEvolution::getTruncateOrNoop(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
(Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate or noop with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&
"getTruncateOrNoop cannot extend!");
@ -2433,7 +2562,7 @@ const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
///
const SCEV *ScalarEvolution::createNodeForGEP(Operator *GEP) {
const Type *IntPtrTy = TD->getIntPtrType(getContext());
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())
@ -2447,19 +2576,16 @@ const SCEV *ScalarEvolution::createNodeForGEP(Operator *GEP) {
// Compute the (potentially symbolic) offset in bytes for this index.
if (const StructType *STy = dyn_cast<StructType>(*GTI++)) {
// For a struct, add the member offset.
const StructLayout &SL = *TD->getStructLayout(STy);
unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
uint64_t Offset = SL.getElementOffset(FieldNo);
TotalOffset = getAddExpr(TotalOffset, getIntegerSCEV(Offset, IntPtrTy));
TotalOffset = getAddExpr(TotalOffset,
getFieldOffsetExpr(STy, FieldNo));
} else {
// For an array, add the element offset, explicitly scaled.
const SCEV *LocalOffset = getSCEV(Index);
if (!isa<PointerType>(LocalOffset->getType()))
// Getelementptr indicies are signed.
LocalOffset = getTruncateOrSignExtend(LocalOffset, IntPtrTy);
LocalOffset =
getMulExpr(LocalOffset,
getIntegerSCEV(TD->getTypeAllocSize(*GTI), IntPtrTy));
LocalOffset = getMulExpr(LocalOffset, getAllocSizeExpr(*GTI));
TotalOffset = getAddExpr(TotalOffset, LocalOffset);
}
}
@ -2952,7 +3078,6 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) {
// expressions we handle are GEPs and address literals.
case Instruction::GetElementPtr:
if (!TD) break; // Without TD we can't analyze pointers.
return createNodeForGEP(U);
case Instruction::PHI:
@ -3947,6 +4072,9 @@ const SCEV *ScalarEvolution::getSCEVAtScope(const SCEV *V, const Loop *L) {
return getTruncateExpr(Op, Cast->getType());
}
if (isa<SCEVTargetDataConstant>(V))
return V;
llvm_unreachable("Unknown SCEV type!");
return 0;
}

315
lib/Analysis/ScalarEvolutionExpander.cpp
View File

@ -158,53 +158,93 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode,
/// check to see if the divide was folded.
static bool FactorOutConstant(const SCEV *&S,
const SCEV *&Remainder,
const APInt &Factor,
ScalarEvolution &SE) {
const SCEV *Factor,
ScalarEvolution &SE,
const TargetData *TD) {
// Everything is divisible by one.
if (Factor == 1)
if (Factor->isOne())
return true;
// x/x == 1.
if (S == Factor) {
S = SE.getIntegerSCEV(1, S->getType());
return true;
}
// For a Constant, check for a multiple of the given factor.
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) {
ConstantInt *CI =
ConstantInt::get(SE.getContext(), C->getValue()->getValue().sdiv(Factor));
// If the quotient is zero and the remainder is non-zero, reject
// the value at this scale. It will be considered for subsequent
// smaller scales.
if (C->isZero() || !CI->isZero()) {
const SCEV *Div = SE.getConstant(CI);
S = Div;
Remainder =
SE.getAddExpr(Remainder,
SE.getConstant(C->getValue()->getValue().srem(Factor)));
// 0/x == 0.
if (C->isZero())
return true;
// Check for divisibility.
if (const SCEVConstant *FC = dyn_cast<SCEVConstant>(Factor)) {
ConstantInt *CI =
ConstantInt::get(SE.getContext(),
C->getValue()->getValue().sdiv(
FC->getValue()->getValue()));
// If the quotient is zero and the remainder is non-zero, reject
// the value at this scale. It will be considered for subsequent
// smaller scales.
if (!CI->isZero()) {
const SCEV *Div = SE.getConstant(CI);
S = Div;
Remainder =
SE.getAddExpr(Remainder,
SE.getConstant(C->getValue()->getValue().srem(
FC->getValue()->getValue())));
return true;
}
}
}
// In a Mul, check if there is a constant operand which is a multiple
// of the given factor.
if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S))
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(M->getOperand(0)))
if (!C->getValue()->getValue().srem(Factor)) {
const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
SmallVector<const SCEV *, 4> NewMulOps(MOperands.begin(),
MOperands.end());
NewMulOps[0] =
SE.getConstant(C->getValue()->getValue().sdiv(Factor));
S = SE.getMulExpr(NewMulOps);
return true;
if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
if (TD) {
// With TargetData, the size is known. Check if there is a constant
// operand which is a multiple of the given factor. If so, we can
// factor it.
const SCEVConstant *FC = cast<SCEVConstant>(Factor);
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(M->getOperand(0)))
if (!C->getValue()->getValue().srem(FC->getValue()->getValue())) {
const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
SmallVector<const SCEV *, 4> NewMulOps(MOperands.begin(),
MOperands.end());
NewMulOps[0] =
SE.getConstant(C->getValue()->getValue().sdiv(
FC->getValue()->getValue()));
S = SE.getMulExpr(NewMulOps);
return true;
}
} else {
// Without TargetData, check if Factor can be factored out of any of the
// Mul's operands. If so, we can just remove it.
for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
const SCEV *SOp = M->getOperand(i);
const SCEV *Remainder = SE.getIntegerSCEV(0, SOp->getType());
if (FactorOutConstant(SOp, Remainder, Factor, SE, TD) &&
Remainder->isZero()) {
const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
SmallVector<const SCEV *, 4> NewMulOps(MOperands.begin(),
MOperands.end());
NewMulOps[i] = SOp;
S = SE.getMulExpr(NewMulOps);
return true;
}
}
}
}
// In an AddRec, check if both start and step are divisible.
if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
const SCEV *Step = A->getStepRecurrence(SE);
const SCEV *StepRem = SE.getIntegerSCEV(0, Step->getType());
if (!FactorOutConstant(Step, StepRem, Factor, SE))
if (!FactorOutConstant(Step, StepRem, Factor, SE, TD))
return false;
if (!StepRem->isZero())
return false;
const SCEV *Start = A->getStart();
if (!FactorOutConstant(Start, Remainder, Factor, SE))
if (!FactorOutConstant(Start, Remainder, Factor, SE, TD))
return false;
S = SE.getAddRecExpr(Start, Step, A->getLoop());
return true;
@ -213,9 +253,73 @@ static bool FactorOutConstant(const SCEV *&S,
return false;
}
/// SimplifyAddOperands - Sort and simplify a list of add operands. NumAddRecs
/// is the number of SCEVAddRecExprs present, which are kept at the end of
/// the list.
///
static void SimplifyAddOperands(SmallVectorImpl<const SCEV *> &Ops,
const Type *Ty,
ScalarEvolution &SE) {
unsigned NumAddRecs = 0;
for (unsigned i = Ops.size(); i > 0 && isa<SCEVAddRecExpr>(Ops[i-1]); --i)
++NumAddRecs;
// Group Ops into non-addrecs and addrecs.
SmallVector<const SCEV *, 8> NoAddRecs(Ops.begin(), Ops.end() - NumAddRecs);
SmallVector<const SCEV *, 8> AddRecs(Ops.end() - NumAddRecs, Ops.end());
// Let ScalarEvolution sort and simplify the non-addrecs list.
const SCEV *Sum = NoAddRecs.empty() ?
SE.getIntegerSCEV(0, Ty) :
SE.getAddExpr(NoAddRecs);
// If it returned an add, use the operands. Otherwise it simplified
// the sum into a single value, so just use that.
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Sum))
Ops = Add->getOperands();
else {
Ops.clear();
if (!Sum->isZero())
Ops.push_back(Sum);
}
// Then append the addrecs.
Ops.insert(Ops.end(), AddRecs.begin(), AddRecs.end());
}
/// SplitAddRecs - Flatten a list of add operands, moving addrec start values
/// out to the top level. For example, convert {a + b,+,c} to a, b, {0,+,d}.
/// This helps expose more opportunities for folding parts of the expressions
/// into GEP indices.
///
static void SplitAddRecs(SmallVectorImpl<const SCEV *> &Ops,
const Type *Ty,
ScalarEvolution &SE) {
// Find the addrecs.
SmallVector<const SCEV *, 8> AddRecs;
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
while (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Ops[i])) {
const SCEV *Start = A->getStart();
if (Start->isZero()) break;
const SCEV *Zero = SE.getIntegerSCEV(0, Ty);
AddRecs.push_back(SE.getAddRecExpr(Zero,
A->getStepRecurrence(SE),
A->getLoop()));
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Start)) {
Ops[i] = Zero;
Ops.insert(Ops.end(), Add->op_begin(), Add->op_end());
e += Add->getNumOperands();
} else {
Ops[i] = Start;
}
}
if (!AddRecs.empty()) {
// Add the addrecs onto the end of the list.
Ops.insert(Ops.end(), AddRecs.begin(), AddRecs.end());
// Resort the operand list, moving any constants to the front.
SimplifyAddOperands(Ops, Ty, SE);
}
}
/// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP
/// instead of using ptrtoint+arithmetic+inttoptr. This helps
/// BasicAliasAnalysis analyze the result.
/// BasicAliasAnalysis and other passes analyze the result.
///
/// Design note: This depends on ScalarEvolution not recognizing inttoptr
/// and ptrtoint operators, as they may introduce pointer arithmetic
@ -246,52 +350,62 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
SmallVector<const SCEV *, 8> Ops(op_begin, op_end);
bool AnyNonZeroIndices = false;
// Split AddRecs up into parts as either of the parts may be usable
// without the other.
SplitAddRecs(Ops, Ty, SE);
// Decend down the pointer's type and attempt to convert the other
// operands into GEP indices, at each level. The first index in a GEP
// indexes into the array implied by the pointer operand; the rest of
// the indices index into the element or field type selected by the
// preceding index.
for (;;) {
APInt ElSize = APInt(SE.getTypeSizeInBits(Ty),
ElTy->isSized() ? SE.TD->getTypeAllocSize(ElTy) : 0);
SmallVector<const SCEV *, 8> NewOps;
const SCEV *ElSize = SE.getAllocSizeExpr(ElTy);
// If the scale size is not 0, attempt to factor out a scale for
// array indexing.
SmallVector<const SCEV *, 8> ScaledOps;
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
// Split AddRecs up into parts as either of the parts may be usable
// without the other.
if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Ops[i]))
if (!A->getStart()->isZero()) {
const SCEV *Start = A->getStart();
Ops.push_back(SE.getAddRecExpr(SE.getIntegerSCEV(0, A->getType()),
A->getStepRecurrence(SE),
A->getLoop()));
Ops[i] = Start;
++e;
}
// If the scale size is not 0, attempt to factor out a scale.
if (ElSize != 0) {
if (ElTy->isSized() && !ElSize->isZero()) {
SmallVector<const SCEV *, 8> NewOps;
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
const SCEV *Op = Ops[i];
const SCEV *Remainder = SE.getIntegerSCEV(0, Op->getType());
if (FactorOutConstant(Op, Remainder, ElSize, SE)) {
ScaledOps.push_back(Op); // Op now has ElSize factored out.
NewOps.push_back(Remainder);
continue;
const SCEV *Remainder = SE.getIntegerSCEV(0, Ty);
if (FactorOutConstant(Op, Remainder, ElSize, SE, SE.TD)) {
// Op now has ElSize factored out.
ScaledOps.push_back(Op);
if (!Remainder->isZero())
NewOps.push_back(Remainder);
AnyNonZeroIndices = true;
} else {
// The operand was not divisible, so add it to the list of operands
// we'll scan next iteration.
NewOps.push_back(Ops[i]);
}
}
// If the operand was not divisible, add it to the list of operands
// we'll scan next iteration.
NewOps.push_back(Ops[i]);
// If we made any changes, update Ops.
if (!ScaledOps.empty()) {
Ops = NewOps;
SimplifyAddOperands(Ops, Ty, SE);
}
}
Ops = NewOps;
AnyNonZeroIndices |= !ScaledOps.empty();
// Record the scaled array index for this level of the type. If
// we didn't find any operands that could be factored, tentatively
// assume that element zero was selected (since the zero offset
// would obviously be folded away).
Value *Scaled = ScaledOps.empty() ?
Constant::getNullValue(Ty) :
expandCodeFor(SE.getAddExpr(ScaledOps), Ty);
GepIndices.push_back(Scaled);
// Collect struct field index operands.
if (!Ops.empty())
while (const StructType *STy = dyn_cast<StructType>(ElTy)) {
while (const StructType *STy = dyn_cast<StructType>(ElTy)) {
bool FoundFieldNo = false;
// An empty struct has no fields.
if (STy->getNumElements() == 0) break;
if (SE.TD) {
// With TargetData, field offsets are known. See if a constant offset
// falls within any of the struct fields.
if (Ops.empty()) break;
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[0]))
if (SE.getTypeSizeInBits(C->getType()) <= 64) {
const StructLayout &SL = *SE.TD->getStructLayout(STy);
@ -304,25 +418,52 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
Ops[0] =
SE.getConstant(Ty, FullOffset - SL.getElementOffset(ElIdx));
AnyNonZeroIndices = true;
continue;
FoundFieldNo = true;
}
}
break;
} else {
// Without TargetData, just check for a SCEVFieldOffsetExpr of the
// appropriate struct type.
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
if (const SCEVFieldOffsetExpr *FO =
dyn_cast<SCEVFieldOffsetExpr>(Ops[i]))
if (FO->getStructType() == STy) {
unsigned FieldNo = FO->getFieldNo();
GepIndices.push_back(
ConstantInt::get(Type::getInt32Ty(Ty->getContext()),
FieldNo));
ElTy = STy->getTypeAtIndex(FieldNo);
Ops[i] = SE.getConstant(Ty, 0);
AnyNonZeroIndices = true;
FoundFieldNo = true;
break;
}
}
// If no struct field offsets were found, tentatively assume that
// field zero was selected (since the zero offset would obviously
// be folded away).
if (!FoundFieldNo) {
ElTy = STy->getTypeAtIndex(0u);
GepIndices.push_back(
Constant::getNullValue(Type::getInt32Ty(Ty->getContext())));
}
if (const ArrayType *ATy = dyn_cast<ArrayType>(ElTy)) {
ElTy = ATy->getElementType();
continue;
}
break;
if (const ArrayType *ATy = dyn_cast<ArrayType>(ElTy))
ElTy = ATy->getElementType();
else
break;
}
// If none of the operands were convertable to proper GEP indices, cast
// the base to i8* and do an ugly getelementptr with that. It's still
// better than ptrtoint+arithmetic+inttoptr at least.
if (!AnyNonZeroIndices) {
// Cast the base to i8*.
V = InsertNoopCastOfTo(V,
Type::getInt8Ty(Ty->getContext())->getPointerTo(PTy->getAddressSpace()));
// Expand the operands for a plain byte offset.
Value *Idx = expandCodeFor(SE.getAddExpr(Ops), Ty);
// Fold a GEP with constant operands.
@ -345,7 +486,8 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
}
}
Value *GEP = Builder.CreateGEP(V, Idx, "scevgep");
// Emit a GEP.
Value *GEP = Builder.CreateGEP(V, Idx, "uglygep");
InsertedValues.insert(GEP);
return GEP;
}
@ -368,11 +510,10 @@ Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
// Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
// comments on expandAddToGEP for details.
if (SE.TD)
if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) {
const SmallVectorImpl<const SCEV *> &Ops = S->getOperands();
return expandAddToGEP(&Ops[0], &Ops[Ops.size() - 1], PTy, Ty, V);
}
if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) {
const SmallVectorImpl<const SCEV *> &Ops = S->getOperands();
return expandAddToGEP(&Ops[0], &Ops[Ops.size() - 1], PTy, Ty, V);
}
V = InsertNoopCastOfTo(V, Ty);
@ -484,21 +625,19 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
// Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
// comments on expandAddToGEP for details.
if (SE.TD) {
const SCEV *Base = S->getStart();
const SCEV *RestArray[1] = { Rest };
// Dig into the expression to find the pointer base for a GEP.
ExposePointerBase(Base, RestArray[0], SE);
// If we found a pointer, expand the AddRec with a GEP.
if (const PointerType *PTy = dyn_cast<PointerType>(Base->getType())) {
// Make sure the Base isn't something exotic, such as a multiplied
// or divided pointer value. In those cases, the result type isn't
// actually a pointer type.
if (!isa<SCEVMulExpr>(Base) && !isa<SCEVUDivExpr>(Base)) {
Value *StartV = expand(Base);
assert(StartV->getType() == PTy && "Pointer type mismatch for GEP!");
return expandAddToGEP(RestArray, RestArray+1, PTy, Ty, StartV);
}
const SCEV *Base = S->getStart();
const SCEV *RestArray[1] = { Rest };
// Dig into the expression to find the pointer base for a GEP.
ExposePointerBase(Base, RestArray[0], SE);
// If we found a pointer, expand the AddRec with a GEP.
if (const PointerType *PTy = dyn_cast<PointerType>(Base->getType())) {
// Make sure the Base isn't something exotic, such as a multiplied
// or divided pointer value. In those cases, the result type isn't
// actually a pointer type.
if (!isa<SCEVMulExpr>(Base) && !isa<SCEVUDivExpr>(Base)) {
Value *StartV = expand(Base);
assert(StartV->getType() == PTy && "Pointer type mismatch for GEP!");
return expandAddToGEP(RestArray, RestArray+1, PTy, Ty, StartV);
}
}
@ -656,6 +795,14 @@ Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
return LHS;
}
Value *SCEVExpander::visitFieldOffsetExpr(const SCEVFieldOffsetExpr *S) {
return ConstantExpr::getOffsetOf(S->getStructType(), S->getFieldNo());
}
Value *SCEVExpander::visitAllocSizeExpr(const SCEVAllocSizeExpr *S) {
return ConstantExpr::getSizeOf(S->getAllocType());
}
Value *SCEVExpander::expandCodeFor(const SCEV *SH, const Type *Ty) {
// Expand the code for this SCEV.
Value *V = expand(SH);

75
test/Transforms/IndVarSimplify/preserve-gep-nested.ll Normal file
View File

@ -0,0 +1,75 @@
; RUN: llvm-as < %s | opt -indvars | llvm-dis > %t
; Exactly one getelementptr for each load+store.
; RUN: grep getelementptr %t | count 6
; Each getelementptr using %struct.Q* %s as a base and not i8*.
; RUN: grep {getelementptr \[%\]struct\\.Q\\* \[%\]s,} %t | count 6
; No explicit integer multiplications!
; RUN: not grep {= mul} %t
; No i8* arithmetic or pointer casting anywhere!
; RUN: not grep {i8\\*} %t
; RUN: not grep bitcast %t
; RUN: not grep inttoptr %t
; RUN: not grep ptrtoint %t
; FIXME: This test should pass with or without TargetData. Until opt
; supports running tests without targetdata, just hardware this in.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
%struct.Q = type { [10 x %struct.N] }
%struct.N = type { %struct.S }
%struct.S = type { [100 x double], [100 x double] }
define void @foo(%struct.Q* %s, i64 %n) nounwind {
entry:
br label %bb1
bb1:
%i = phi i64 [ 2, %entry ], [ %i.next, %bb ]
%j = phi i64 [ 0, %entry ], [ %j.next, %bb ]
%t5 = icmp slt i64 %i, %n
br i1 %t5, label %bb, label %return
bb:
%t0 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 0, i32 0, i32 0, i64 %i
%t1 = load double* %t0, align 8
%t2 = fmul double %t1, 3.200000e+00
%t3 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 0, i32 0, i32 0, i64 %i
store double %t2, double* %t3, align 8
%s0 = getelementptr inbounds %struct.Q* %s, i64 13, i32 0, i64 7, i32 0, i32 1, i64 %i
%s1 = load double* %s0, align 8
%s2 = fmul double %s1, 3.200000e+00
%s3 = getelementptr inbounds %struct.Q* %s, i64 13, i32 0, i64 7, i32 0, i32 1, i64 %i
store double %s2, double* %s3, align 8
%u0 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 7, i32 0, i32 1, i64 %j
%u1 = load double* %u0, align 8
%u2 = fmul double %u1, 3.200000e+00
%u3 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 7, i32 0, i32 1, i64 %j
store double %u2, double* %u3, align 8
%v0 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 0, i32 0, i32 1, i64 %i
%v1 = load double* %v0, align 8
%v2 = fmul double %v1, 3.200000e+00
%v3 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 0, i32 0, i32 1, i64 %i
store double %v2, double* %v3, align 8
%w0 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 0, i32 0, i32 0, i64 %j
%w1 = load double* %w0, align 8
%w2 = fmul double %w1, 3.200000e+00
%w3 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 0, i32 0, i32 0, i64 %j
store double %w2, double* %w3, align 8
%x0 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 3, i32 0, i32 0, i64 %i
%x1 = load double* %x0, align 8
%x2 = fmul double %x1, 3.200000e+00
%x3 = getelementptr inbounds %struct.Q* %s, i64 0, i32 0, i64 3, i32 0, i32 0, i64 %i
store double %x2, double* %x3, align 8
%i.next = add i64 %i, 1
%j.next = add i64 %j, 1
br label %bb1
return:
ret void
}