}
return;
}
+ if (ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V)) {
+ // We know that CDS must be a vector of integers. Take the intersection of
+ // each element.
+ KnownZero.setAllBits(); KnownOne.setAllBits();
+ APInt Elt(KnownZero.getBitWidth(), 0);
+ for (unsigned i = 0, e = CDS->getType()->getNumElements(); i != e; ++i) {
+ Elt = CDS->getElementAsInteger(i);
+ KnownZero &= ~Elt;
+ KnownOne &= Elt;
+ }
+ return;
+ }
+
// The address of an aligned GlobalValue has trailing zeros.
if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
unsigned Align = GV->getAlignment();
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
switch (II->getIntrinsicID()) {
default: break;
- case Intrinsic::ctpop:
case Intrinsic::ctlz:
case Intrinsic::cttz: {
+ unsigned LowBits = Log2_32(BitWidth)+1;
+ // If this call is undefined for 0, the result will be less than 2^n.
+ if (II->getArgOperand(1) == ConstantInt::getTrue(II->getContext()))
+ LowBits -= 1;
+ KnownZero = APInt::getHighBitsSet(BitWidth, BitWidth - LowBits);
+ break;
+ }
+ case Intrinsic::ctpop: {
unsigned LowBits = Log2_32(BitWidth)+1;
KnownZero = APInt::getHighBitsSet(BitWidth, BitWidth - LowBits);
break;
// An exact divide or right shift can only shift off zero bits, so the result
// is a power of two only if the first operand is a power of two and not
// copying a sign bit (sdiv int_min, 2).
- if (match(V, m_LShr(m_Value(), m_Value())) ||
- match(V, m_UDiv(m_Value(), m_Value()))) {
- PossiblyExactOperator *PEO = cast<PossiblyExactOperator>(V);
- if (PEO->isExact())
- return isPowerOfTwo(PEO->getOperand(0), TD, OrZero, Depth);
+ if (match(V, m_Exact(m_LShr(m_Value(), m_Value()))) ||
+ match(V, m_Exact(m_UDiv(m_Value(), m_Value())))) {
+ return isPowerOfTwo(cast<Operator>(V)->getOperand(0), TD, OrZero, Depth);
}
return false;
return true;
}
// div exact can only produce a zero if the dividend is zero.
- else if (match(V, m_IDiv(m_Value(X), m_Value()))) {
- PossiblyExactOperator *BO = cast<PossiblyExactOperator>(V);
- if (BO->isExact())
- return isKnownNonZero(X, TD, Depth);
+ else if (match(V, m_Exact(m_IDiv(m_Value(X), m_Value())))) {
+ return isKnownNonZero(X, TD, Depth);
}
// X + Y.
else if (match(V, m_Add(m_Value(X), m_Value(Y)))) {
Value *llvm::FindInsertedValue(Value *V, ArrayRef<unsigned> idx_range,
Instruction *InsertBefore) {
// Nothing to index? Just return V then (this is useful at the end of our
- // recursion)
+ // recursion).
if (idx_range.empty())
return V;
- // We have indices, so V should have an indexable type
- assert((V->getType()->isStructTy() || V->getType()->isArrayTy())
- && "Not looking at a struct or array?");
- assert(ExtractValueInst::getIndexedType(V->getType(), idx_range)
- && "Invalid indices for type?");
+ // We have indices, so V should have an indexable type.
+ assert((V->getType()->isStructTy() || V->getType()->isArrayTy()) &&
+ "Not looking at a struct or array?");
+ assert(ExtractValueInst::getIndexedType(V->getType(), idx_range) &&
+ "Invalid indices for type?");
CompositeType *PTy = cast<CompositeType>(V->getType());
if (isa<UndefValue>(V))
- return UndefValue::get(ExtractValueInst::getIndexedType(PTy,
- idx_range));
- else if (isa<ConstantAggregateZero>(V))
+ return UndefValue::get(ExtractValueInst::getIndexedType(PTy, idx_range));
+ if (isa<ConstantAggregateZero>(V))
return Constant::getNullValue(ExtractValueInst::getIndexedType(PTy,
idx_range));
- else if (Constant *C = dyn_cast<Constant>(V)) {
- if (isa<ConstantArray>(C) || isa<ConstantStruct>(C))
- // Recursively process this constant
- return FindInsertedValue(C->getOperand(idx_range[0]), idx_range.slice(1),
- InsertBefore);
- } else if (InsertValueInst *I = dyn_cast<InsertValueInst>(V)) {
+ if (isa<ConstantArray>(V) || isa<ConstantStruct>(V))
+ // Recursively process this constant
+ return FindInsertedValue(cast<Constant>(V)->getOperand(idx_range[0]),
+ idx_range.slice(1), InsertBefore);
+ if (ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
+ return CDS->getElementAsConstant(idx_range[0]);
+
+ if (InsertValueInst *I = dyn_cast<InsertValueInst>(V)) {
// Loop the indices for the insertvalue instruction in parallel with the
// requested indices
const unsigned *req_idx = idx_range.begin();
for (const unsigned *i = I->idx_begin(), *e = I->idx_end();
i != e; ++i, ++req_idx) {
if (req_idx == idx_range.end()) {
- if (InsertBefore)
- // The requested index identifies a part of a nested aggregate. Handle
- // this specially. For example,
- // %A = insertvalue { i32, {i32, i32 } } undef, i32 10, 1, 0
- // %B = insertvalue { i32, {i32, i32 } } %A, i32 11, 1, 1
- // %C = extractvalue {i32, { i32, i32 } } %B, 1
- // This can be changed into
- // %A = insertvalue {i32, i32 } undef, i32 10, 0
- // %C = insertvalue {i32, i32 } %A, i32 11, 1
- // which allows the unused 0,0 element from the nested struct to be
- // removed.
- return BuildSubAggregate(V, makeArrayRef(idx_range.begin(), req_idx),
- InsertBefore);
- else
- // We can't handle this without inserting insertvalues
+ // We can't handle this without inserting insertvalues
+ if (!InsertBefore)
return 0;
+
+ // The requested index identifies a part of a nested aggregate. Handle
+ // this specially. For example,
+ // %A = insertvalue { i32, {i32, i32 } } undef, i32 10, 1, 0
+ // %B = insertvalue { i32, {i32, i32 } } %A, i32 11, 1, 1
+ // %C = extractvalue {i32, { i32, i32 } } %B, 1
+ // This can be changed into
+ // %A = insertvalue {i32, i32 } undef, i32 10, 0
+ // %C = insertvalue {i32, i32 } %A, i32 11, 1
+ // which allows the unused 0,0 element from the nested struct to be
+ // removed.
+ return BuildSubAggregate(V, makeArrayRef(idx_range.begin(), req_idx),
+ InsertBefore);
}
// This insert value inserts something else than what we are looking for.
return FindInsertedValue(I->getInsertedValueOperand(),
makeArrayRef(req_idx, idx_range.end()),
InsertBefore);
- } else if (ExtractValueInst *I = dyn_cast<ExtractValueInst>(V)) {
+ }
+
+ if (ExtractValueInst *I = dyn_cast<ExtractValueInst>(V)) {
// If we're extracting a value from an aggregrate that was extracted from
// something else, we can extract from that something else directly instead.
// However, we will need to chain I's indices with the requested indices.
}
return true;
}
+
+bool llvm::isSafeToSpeculativelyExecute(const Value *V,
+ const TargetData *TD) {
+ const Operator *Inst = dyn_cast<Operator>(V);
+ if (!Inst)
+ return false;
+
+ for (unsigned i = 0, e = Inst->getNumOperands(); i != e; ++i)
+ if (Constant *C = dyn_cast<Constant>(Inst->getOperand(i)))
+ if (C->canTrap())
+ return false;
+
+ switch (Inst->getOpcode()) {
+ default:
+ return true;
+ case Instruction::UDiv:
+ case Instruction::URem:
+ // x / y is undefined if y == 0, but calcuations like x / 3 are safe.
+ return isKnownNonZero(Inst->getOperand(1), TD);
+ case Instruction::SDiv:
+ case Instruction::SRem: {
+ Value *Op = Inst->getOperand(1);
+ // x / y is undefined if y == 0
+ if (!isKnownNonZero(Op, TD))
+ return false;
+ // x / y might be undefined if y == -1
+ unsigned BitWidth = getBitWidth(Op->getType(), TD);
+ if (BitWidth == 0)
+ return false;
+ APInt KnownZero(BitWidth, 0);
+ APInt KnownOne(BitWidth, 0);
+ ComputeMaskedBits(Op, APInt::getAllOnesValue(BitWidth),
+ KnownZero, KnownOne, TD);
+ return !!KnownZero;
+ }
+ case Instruction::Load: {
+ const LoadInst *LI = cast<LoadInst>(Inst);
+ if (!LI->isUnordered())
+ return false;
+ return LI->getPointerOperand()->isDereferenceablePointer();
+ }
+ case Instruction::Call: {
+ if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
+ switch (II->getIntrinsicID()) {
+ case Intrinsic::bswap:
+ case Intrinsic::ctlz:
+ case Intrinsic::ctpop:
+ case Intrinsic::cttz:
+ case Intrinsic::objectsize:
+ case Intrinsic::sadd_with_overflow:
+ case Intrinsic::smul_with_overflow:
+ case Intrinsic::ssub_with_overflow:
+ case Intrinsic::uadd_with_overflow:
+ case Intrinsic::umul_with_overflow:
+ case Intrinsic::usub_with_overflow:
+ return true;
+ // TODO: some fp intrinsics are marked as having the same error handling
+ // as libm. They're safe to speculate when they won't error.
+ // TODO: are convert_{from,to}_fp16 safe?
+ // TODO: can we list target-specific intrinsics here?
+ default: break;
+ }
+ }
+ return false; // The called function could have undefined behavior or
+ // side-effects, even if marked readnone nounwind.
+ }
+ case Instruction::VAArg:
+ case Instruction::Alloca:
+ case Instruction::Invoke:
+ case Instruction::PHI:
+ case Instruction::Store:
+ case Instruction::Ret:
+ case Instruction::Br:
+ case Instruction::IndirectBr:
+ case Instruction::Switch:
+ case Instruction::Unwind:
+ case Instruction::Unreachable:
+ case Instruction::Fence:
+ case Instruction::LandingPad:
+ case Instruction::AtomicRMW:
+ case Instruction::AtomicCmpXchg:
+ case Instruction::Resume:
+ return false; // Misc instructions which have effects
+ }
+}
projects / oota-llvm.git / blobdiff