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Make the unsigned-range code more consistent with the signed-range code,

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and clean up some loose ends.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94572 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-01-26 19:19:05 +00:00
parent ddc419c581
commit c9c36cb3d9
1 changed files with 29 additions and 25 deletions
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54
lib/Analysis/ScalarEvolution.cpp
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@ -2797,62 +2797,67 @@ 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 X;
return ConservativeResult.intersectWith(X);
}
if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
ConstantRange X = getUnsignedRange(Mul->getOperand(0));
for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i)
X = X.multiply(getUnsignedRange(Mul->getOperand(i)));
return X;
return ConservativeResult.intersectWith(X);
}
if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) {
ConstantRange X = getUnsignedRange(SMax->getOperand(0));
for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i)
X = X.smax(getUnsignedRange(SMax->getOperand(i)));
return X;
return ConservativeResult.intersectWith(X);
}
if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) {
ConstantRange X = getUnsignedRange(UMax->getOperand(0));
for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i)
X = X.umax(getUnsignedRange(UMax->getOperand(i)));
return X;
return ConservativeResult.intersectWith(X);
}
if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
ConstantRange X = getUnsignedRange(UDiv->getLHS());
ConstantRange Y = getUnsignedRange(UDiv->getRHS());
return X.udiv(Y);
return ConservativeResult.intersectWith(X.udiv(Y));
}
if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
ConstantRange X = getUnsignedRange(ZExt->getOperand());
return X.zeroExtend(cast<IntegerType>(ZExt->getType())->getBitWidth());
return ConservativeResult.intersectWith(X.zeroExtend(BitWidth));
}
if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
ConstantRange X = getUnsignedRange(SExt->getOperand());
return X.signExtend(cast<IntegerType>(SExt->getType())->getBitWidth());
return ConservativeResult.intersectWith(X.signExtend(BitWidth));
}
if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
ConstantRange X = getUnsignedRange(Trunc->getOperand());
return X.truncate(cast<IntegerType>(Trunc->getType())->getBitWidth());
return ConservativeResult.intersectWith(X.truncate(BitWidth));
}
ConstantRange FullSet(getTypeSizeInBits(S->getType()), true);
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
const SCEV *T = getBackedgeTakenCount(AddRec->getLoop());
const SCEVConstant *Trip = dyn_cast<SCEVConstant>(T);
ConstantRange ConservativeResult = FullSet;
// If there's no unsigned wrap, the value will never be less than its
// initial value.
if (AddRec->hasNoUnsignedWrap())
@ -2862,10 +2867,11 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) {
APInt(getTypeSizeInBits(C->getType()), 0));
// TODO: non-affine addrec
if (Trip && AddRec->isAffine()) {
if (AddRec->isAffine()) {
const Type *Ty = AddRec->getType();
const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
if (getTypeSizeInBits(MaxBECount->getType()) <= getTypeSizeInBits(Ty)) {
if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
MaxBECount = getNoopOrZeroExtend(MaxBECount, Ty);
const SCEV *Start = AddRec->getStart();
@ -2883,7 +2889,7 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) {
EndRange.getUnsignedMax());
if (Min.isMinValue() && Max.isMaxValue())
return ConservativeResult;
return ConstantRange(Min, Max+1);
return ConservativeResult.intersectWith(ConstantRange(Min, Max+1));
}
}
@ -2897,11 +2903,11 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) {
APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD);
if (Ones == ~Zeros + 1)
return FullSet;
return ConstantRange(Ones, ~Zeros + 1);
return ConservativeResult;
return ConservativeResult.intersectWith(ConstantRange(Ones, ~Zeros + 1));
}
return FullSet;
return ConservativeResult;
}
/// getSignedRange - Determine the signed range for a particular SCEV.
@ -2973,9 +2979,6 @@ ScalarEvolution::getSignedRange(const SCEV *S) {
}
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
const SCEV *T = getBackedgeTakenCount(AddRec->getLoop());
const SCEVConstant *Trip = dyn_cast<SCEVConstant>(T);
// 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()) {
@ -2996,10 +2999,11 @@ ScalarEvolution::getSignedRange(const SCEV *S) {
}
// TODO: non-affine addrec
if (Trip && AddRec->isAffine()) {
if (AddRec->isAffine()) {
const Type *Ty = AddRec->getType();
const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
if (getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
MaxBECount = getNoopOrZeroExtend(MaxBECount, Ty);
const SCEV *Start = AddRec->getStart();