//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Analysis/AssumptionTracker.h"
+#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
// figuring out if we can use it.
struct Query {
ExclInvsSet ExclInvs;
- AssumptionTracker *AT;
+ AssumptionCache *AC;
const Instruction *CxtI;
const DominatorTree *DT;
- Query(AssumptionTracker *AT = nullptr, const Instruction *CxtI = nullptr,
+ Query(AssumptionCache *AC = nullptr, const Instruction *CxtI = nullptr,
const DominatorTree *DT = nullptr)
- : AT(AT), CxtI(CxtI), DT(DT) {}
+ : AC(AC), CxtI(CxtI), DT(DT) {}
Query(const Query &Q, const Value *NewExcl)
- : ExclInvs(Q.ExclInvs), AT(Q.AT), CxtI(Q.CxtI), DT(Q.DT) {
+ : ExclInvs(Q.ExclInvs), AC(Q.AC), CxtI(Q.CxtI), DT(Q.DT) {
ExclInvs.insert(NewExcl);
}
};
void llvm::computeKnownBits(Value *V, APInt &KnownZero, APInt &KnownOne,
const DataLayout *TD, unsigned Depth,
- AssumptionTracker *AT, const Instruction *CxtI,
+ AssumptionCache *AC, const Instruction *CxtI,
const DominatorTree *DT) {
::computeKnownBits(V, KnownZero, KnownOne, TD, Depth,
- Query(AT, safeCxtI(V, CxtI), DT));
+ Query(AC, safeCxtI(V, CxtI), DT));
}
static void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
void llvm::ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
const DataLayout *TD, unsigned Depth,
- AssumptionTracker *AT, const Instruction *CxtI,
+ AssumptionCache *AC, const Instruction *CxtI,
const DominatorTree *DT) {
::ComputeSignBit(V, KnownZero, KnownOne, TD, Depth,
- Query(AT, safeCxtI(V, CxtI), DT));
+ Query(AC, safeCxtI(V, CxtI), DT));
}
static bool isKnownToBeAPowerOfTwo(Value *V, bool OrZero, unsigned Depth,
const Query &Q);
bool llvm::isKnownToBeAPowerOfTwo(Value *V, bool OrZero, unsigned Depth,
- AssumptionTracker *AT,
- const Instruction *CxtI,
+ AssumptionCache *AC, const Instruction *CxtI,
const DominatorTree *DT) {
return ::isKnownToBeAPowerOfTwo(V, OrZero, Depth,
- Query(AT, safeCxtI(V, CxtI), DT));
+ Query(AC, safeCxtI(V, CxtI), DT));
}
static bool isKnownNonZero(Value *V, const DataLayout *TD, unsigned Depth,
const Query &Q);
bool llvm::isKnownNonZero(Value *V, const DataLayout *TD, unsigned Depth,
- AssumptionTracker *AT, const Instruction *CxtI,
+ AssumptionCache *AC, const Instruction *CxtI,
const DominatorTree *DT) {
- return ::isKnownNonZero(V, TD, Depth, Query(AT, safeCxtI(V, CxtI), DT));
+ return ::isKnownNonZero(V, TD, Depth, Query(AC, safeCxtI(V, CxtI), DT));
}
static bool MaskedValueIsZero(Value *V, const APInt &Mask,
const DataLayout *TD, unsigned Depth,
const Query &Q);
-bool llvm::MaskedValueIsZero(Value *V, const APInt &Mask,
- const DataLayout *TD, unsigned Depth,
- AssumptionTracker *AT, const Instruction *CxtI,
- const DominatorTree *DT) {
+bool llvm::MaskedValueIsZero(Value *V, const APInt &Mask, const DataLayout *TD,
+ unsigned Depth, AssumptionCache *AC,
+ const Instruction *CxtI, const DominatorTree *DT) {
return ::MaskedValueIsZero(V, Mask, TD, Depth,
- Query(AT, safeCxtI(V, CxtI), DT));
+ Query(AC, safeCxtI(V, CxtI), DT));
}
static unsigned ComputeNumSignBits(Value *V, const DataLayout *TD,
unsigned Depth, const Query &Q);
unsigned llvm::ComputeNumSignBits(Value *V, const DataLayout *TD,
- unsigned Depth, AssumptionTracker *AT,
+ unsigned Depth, AssumptionCache *AC,
const Instruction *CxtI,
const DominatorTree *DT) {
- return ::ComputeNumSignBits(V, TD, Depth, Query(AT, safeCxtI(V, CxtI), DT));
+ return ::ComputeNumSignBits(V, TD, Depth, Query(AC, safeCxtI(V, CxtI), DT));
}
static void computeKnownBitsAddSub(bool Add, Value *Op0, Value *Op1, bool NSW,
// Use the high end of the ranges to find leading zeros.
unsigned MinLeadingZeros = BitWidth;
for (unsigned i = 0; i < NumRanges; ++i) {
- ConstantInt *Lower = cast<ConstantInt>(Ranges.getOperand(2*i + 0));
- ConstantInt *Upper = cast<ConstantInt>(Ranges.getOperand(2*i + 1));
+ ConstantInt *Lower =
+ mdconst::extract<ConstantInt>(Ranges.getOperand(2 * i + 0));
+ ConstantInt *Upper =
+ mdconst::extract<ConstantInt>(Ranges.getOperand(2 * i + 1));
ConstantRange Range(Lower->getValue(), Upper->getValue());
if (Range.isWrappedSet())
MinLeadingZeros = 0; // -1 has no zeros
while (!WorkSet.empty()) {
const Value *V = WorkSet.pop_back_val();
- if (!Visited.insert(V))
+ if (!Visited.insert(V).second)
continue;
// If all uses of this value are ephemeral, then so is this value.
unsigned Depth, const Query &Q) {
// Use of assumptions is context-sensitive. If we don't have a context, we
// cannot use them!
- if (!Q.AT || !Q.CxtI)
+ if (!Q.AC || !Q.CxtI)
return;
unsigned BitWidth = KnownZero.getBitWidth();
Function *F = const_cast<Function*>(Q.CxtI->getParent()->getParent());
- for (auto &CI : Q.AT->assumptions(F)) {
- CallInst *I = CI;
+ for (auto &AssumeVH : Q.AC->assumptions()) {
+ if (!AssumeVH)
+ continue;
+ CallInst *I = cast<CallInst>(AssumeVH);
+ assert(I->getParent()->getParent() == F &&
+ "Got assumption for the wrong function!");
if (Q.ExclInvs.count(I))
continue;
- if (match(I, m_Intrinsic<Intrinsic::assume>(m_Specific(V))) &&
+ // Warning: This loop can end up being somewhat performance sensetive.
+ // We're running this loop for once for each value queried resulting in a
+ // runtime of ~O(#assumes * #values).
+
+ assert(isa<IntrinsicInst>(I) &&
+ dyn_cast<IntrinsicInst>(I)->getIntrinsicID() == Intrinsic::assume &&
+ "must be an assume intrinsic");
+
+ Value *Arg = I->getArgOperand(0);
+
+ if (Arg == V &&
isValidAssumeForContext(I, Q, DL)) {
assert(BitWidth == 1 && "assume operand is not i1?");
KnownZero.clearAllBits();
return;
}
+ // The remaining tests are all recursive, so bail out if we hit the limit.
+ if (Depth == MaxDepth)
+ continue;
+
Value *A, *B;
auto m_V = m_CombineOr(m_Specific(V),
m_CombineOr(m_PtrToInt(m_Specific(V)),
CmpInst::Predicate Pred;
ConstantInt *C;
// assume(v = a)
- if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_V, m_Value(A)))) &&
+ if (match(Arg, m_c_ICmp(Pred, m_V, m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownZero;
KnownOne |= RHSKnownOne;
// assume(v & b = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_c_And(m_V, m_Value(B)), m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_c_And(m_V, m_Value(B)),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownZero & MaskKnownOne;
KnownOne |= RHSKnownOne & MaskKnownOne;
// assume(~(v & b) = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_Not(m_c_And(m_V, m_Value(B))),
- m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_c_And(m_V, m_Value(B))),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownOne & MaskKnownOne;
KnownOne |= RHSKnownZero & MaskKnownOne;
// assume(v | b = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_c_Or(m_V, m_Value(B)), m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_c_Or(m_V, m_Value(B)),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownZero & BKnownZero;
KnownOne |= RHSKnownOne & BKnownZero;
// assume(~(v | b) = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_Not(m_c_Or(m_V, m_Value(B))),
- m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_c_Or(m_V, m_Value(B))),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownOne & BKnownZero;
KnownOne |= RHSKnownZero & BKnownZero;
// assume(v ^ b = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_c_Xor(m_V, m_Value(B)), m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_c_Xor(m_V, m_Value(B)),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownOne & BKnownOne;
KnownOne |= RHSKnownZero & BKnownOne;
// assume(~(v ^ b) = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_Not(m_c_Xor(m_V, m_Value(B))),
- m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_c_Xor(m_V, m_Value(B))),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownZero & BKnownOne;
KnownOne |= RHSKnownOne & BKnownOne;
// assume(v << c = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_Shl(m_V, m_ConstantInt(C)),
- m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_Shl(m_V, m_ConstantInt(C)),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownZero.lshr(C->getZExtValue());
KnownOne |= RHSKnownOne.lshr(C->getZExtValue());
// assume(~(v << c) = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_Not(m_Shl(m_V, m_ConstantInt(C))),
- m_Value(A)))) &&
+ } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_Shl(m_V, m_ConstantInt(C))),
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownOne.lshr(C->getZExtValue());
KnownOne |= RHSKnownZero.lshr(C->getZExtValue());
// assume(v >> c = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_CombineOr(m_LShr(m_V, m_ConstantInt(C)),
+ } else if (match(Arg,
+ m_c_ICmp(Pred, m_CombineOr(m_LShr(m_V, m_ConstantInt(C)),
m_AShr(m_V,
m_ConstantInt(C))),
- m_Value(A)))) &&
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownZero << C->getZExtValue();
KnownOne |= RHSKnownOne << C->getZExtValue();
// assume(~(v >> c) = a)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_c_ICmp(Pred, m_Not(m_CombineOr(
+ } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_CombineOr(
m_LShr(m_V, m_ConstantInt(C)),
m_AShr(m_V, m_ConstantInt(C)))),
- m_Value(A)))) &&
+ m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownZero |= RHSKnownOne << C->getZExtValue();
KnownOne |= RHSKnownZero << C->getZExtValue();
// assume(v >=_s c) where c is non-negative
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_ICmp(Pred, m_V, m_Value(A)))) &&
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
Pred == ICmpInst::ICMP_SGE &&
isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
KnownZero |= APInt::getSignBit(BitWidth);
}
// assume(v >_s c) where c is at least -1.
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_ICmp(Pred, m_V, m_Value(A)))) &&
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
Pred == ICmpInst::ICMP_SGT &&
isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
KnownZero |= APInt::getSignBit(BitWidth);
}
// assume(v <=_s c) where c is negative
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_ICmp(Pred, m_V, m_Value(A)))) &&
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
Pred == ICmpInst::ICMP_SLE &&
isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
KnownOne |= APInt::getSignBit(BitWidth);
}
// assume(v <_s c) where c is non-positive
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_ICmp(Pred, m_V, m_Value(A)))) &&
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
Pred == ICmpInst::ICMP_SLT &&
isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
KnownOne |= APInt::getSignBit(BitWidth);
}
// assume(v <=_u c)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_ICmp(Pred, m_V, m_Value(A)))) &&
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
Pred == ICmpInst::ICMP_ULE &&
isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
KnownZero |=
APInt::getHighBitsSet(BitWidth, RHSKnownZero.countLeadingOnes());
// assume(v <_u c)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_ICmp(Pred, m_V, m_Value(A)))) &&
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
Pred == ICmpInst::ICMP_ULT &&
isValidAssumeForContext(I, Q, DL)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
return;
}
- // A weak GlobalAlias is totally unknown. A non-weak GlobalAlias has
- // the bits of its aliasee.
- if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
- if (GA->mayBeOverridden()) {
- KnownZero.clearAllBits(); KnownOne.clearAllBits();
- } else {
- computeKnownBits(GA->getAliasee(), KnownZero, KnownOne, TD, Depth+1, Q);
- }
- return;
- }
-
// The address of an aligned GlobalValue has trailing zeros.
- if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
- unsigned Align = GV->getAlignment();
+ if (auto *GO = dyn_cast<GlobalObject>(V)) {
+ unsigned Align = GO->getAlignment();
if (Align == 0 && TD) {
- if (GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
+ if (auto *GVar = dyn_cast<GlobalVariable>(GO)) {
Type *ObjectType = GVar->getType()->getElementType();
if (ObjectType->isSized()) {
// If the object is defined in the current Module, we'll be giving
if (Align)
KnownZero = APInt::getLowBitsSet(BitWidth, countTrailingZeros(Align));
+ else
+ KnownZero.clearAllBits();
+ KnownOne.clearAllBits();
// Don't give up yet... there might be an assumption that provides more
// information...
// Start out not knowing anything.
KnownZero.clearAllBits(); KnownOne.clearAllBits();
+ // Limit search depth.
+ // All recursive calls that increase depth must come after this.
if (Depth == MaxDepth)
- return; // Limit search depth.
+ return;
+
+ // A weak GlobalAlias is totally unknown. A non-weak GlobalAlias has
+ // the bits of its aliasee.
+ if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
+ if (!GA->mayBeOverridden())
+ computeKnownBits(GA->getAliasee(), KnownZero, KnownOne, TD, Depth + 1, Q);
+ return;
+ }
// Check whether a nearby assume intrinsic can determine some known bits.
computeKnownBitsFromAssume(V, KnownZero, KnownOne, TD, Depth, Q);
switch (I->getOpcode()) {
default: break;
case Instruction::Load:
- if (MDNode *MD = cast<LoadInst>(I)->getMDNode(LLVMContext::MD_range))
+ if (MDNode *MD = cast<LoadInst>(I)->getMetadata(LLVMContext::MD_range))
computeKnownBitsFromRangeMetadata(*MD, KnownZero);
break;
case Instruction::And: {
KnownZero <<= ShiftAmt;
KnownOne <<= ShiftAmt;
KnownZero |= APInt::getLowBitsSet(BitWidth, ShiftAmt); // low bits known 0
- break;
}
break;
case Instruction::LShr:
uint64_t ShiftAmt = SA->getLimitedValue(BitWidth);
// Unsigned shift right.
- computeKnownBits(I->getOperand(0), KnownZero,KnownOne, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
KnownZero = APIntOps::lshr(KnownZero, ShiftAmt);
KnownOne = APIntOps::lshr(KnownOne, ShiftAmt);
// high bits known zero.
KnownZero |= APInt::getHighBitsSet(BitWidth, ShiftAmt);
- break;
}
break;
case Instruction::AShr:
KnownZero |= HighBits;
else if (KnownOne[BitWidth-ShiftAmt-1]) // New bits are known one.
KnownOne |= HighBits;
- break;
}
break;
case Instruction::Sub: {
}
case Instruction::Call:
case Instruction::Invoke:
- if (MDNode *MD = cast<Instruction>(I)->getMDNode(LLVMContext::MD_range))
+ if (MDNode *MD = cast<Instruction>(I)->getMetadata(LLVMContext::MD_range))
computeKnownBitsFromRangeMetadata(*MD, KnownZero);
// If a range metadata is attached to this IntrinsicInst, intersect the
// explicit range specified by the metadata and the implicit range of
const unsigned NumRanges = Ranges->getNumOperands() / 2;
assert(NumRanges >= 1);
for (unsigned i = 0; i < NumRanges; ++i) {
- ConstantInt *Lower = cast<ConstantInt>(Ranges->getOperand(2*i + 0));
- ConstantInt *Upper = cast<ConstantInt>(Ranges->getOperand(2*i + 1));
+ ConstantInt *Lower =
+ mdconst::extract<ConstantInt>(Ranges->getOperand(2 * i + 0));
+ ConstantInt *Upper =
+ mdconst::extract<ConstantInt>(Ranges->getOperand(2 * i + 1));
ConstantRange Range(Lower->getValue(), Upper->getValue());
if (Range.contains(Value))
return false;
}
if (Instruction* I = dyn_cast<Instruction>(V)) {
- if (MDNode *Ranges = I->getMDNode(LLVMContext::MD_range)) {
+ if (MDNode *Ranges = I->getMetadata(LLVMContext::MD_range)) {
// If the possible ranges don't contain zero, then the value is
// definitely non-zero.
if (IntegerType* Ty = dyn_cast<IntegerType>(V->getType())) {
if (Tmp == 1) return 1; // Early out.
// Special case decrementing a value (ADD X, -1):
- if (ConstantInt *CRHS = dyn_cast<ConstantInt>(U->getOperand(1)))
+ if (const auto *CRHS = dyn_cast<Constant>(U->getOperand(1)))
if (CRHS->isAllOnesValue()) {
APInt KnownZero(TyBits, 0), KnownOne(TyBits, 0);
computeKnownBits(U->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
if (Tmp2 == 1) return 1;
// Handle NEG.
- if (ConstantInt *CLHS = dyn_cast<ConstantInt>(U->getOperand(0)))
+ if (const auto *CLHS = dyn_cast<Constant>(U->getOperand(0)))
if (CLHS->isNullValue()) {
APInt KnownZero(TyBits, 0), KnownOne(TyBits, 0);
computeKnownBits(U->getOperand(1), KnownZero, KnownOne, TD, Depth+1, Q);
case Instruction::PHI: {
PHINode *PN = cast<PHINode>(U);
+ unsigned NumIncomingValues = PN->getNumIncomingValues();
// Don't analyze large in-degree PHIs.
- if (PN->getNumIncomingValues() > 4) break;
+ if (NumIncomingValues > 4) break;
+ // Unreachable blocks may have zero-operand PHI nodes.
+ if (NumIncomingValues == 0) break;
// Take the minimum of all incoming values. This can't infinitely loop
// because of our depth threshold.
Tmp = ComputeNumSignBits(PN->getIncomingValue(0), TD, Depth+1, Q);
- for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
+ for (unsigned i = 1, e = NumIncomingValues; i != e; ++i) {
if (Tmp == 1) return Tmp;
Tmp = std::min(Tmp,
ComputeNumSignBits(PN->getIncomingValue(i), TD,
// If this is a PHI node, there are two cases: either we have already seen it
// or we haven't.
if (PHINode *PN = dyn_cast<PHINode>(V)) {
- if (!PHIs.insert(PN))
+ if (!PHIs.insert(PN).second)
return ~0ULL; // already in the set.
// If it was new, see if all the input strings are the same length.
} else {
// See if InstructionSimplify knows any relevant tricks.
if (Instruction *I = dyn_cast<Instruction>(V))
- // TODO: Acquire a DominatorTree and AssumptionTracker and use them.
+ // TODO: Acquire a DominatorTree and AssumptionCache and use them.
if (Value *Simplified = SimplifyInstruction(I, TD, nullptr)) {
V = Simplified;
continue;
Value *P = Worklist.pop_back_val();
P = GetUnderlyingObject(P, TD, MaxLookup);
- if (!Visited.insert(P))
+ if (!Visited.insert(P).second)
continue;
if (SelectInst *SI = dyn_cast<SelectInst>(P)) {
return LI->getPointerOperand()->isDereferenceablePointer(TD);
}
case Instruction::Call: {
- if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
- switch (II->getIntrinsicID()) {
- // These synthetic intrinsics have no side-effects and just mark
- // information about their operands.
- // FIXME: There are other no-op synthetic instructions that potentially
- // should be considered at least *safe* to speculate...
- case Intrinsic::dbg_declare:
- case Intrinsic::dbg_value:
- return true;
-
- 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;
- // Sqrt should be OK, since the llvm sqrt intrinsic isn't defined to set
- // errno like libm sqrt would.
- case Intrinsic::sqrt:
- case Intrinsic::fma:
- case Intrinsic::fmuladd:
- case Intrinsic::fabs:
- case Intrinsic::minnum:
- case Intrinsic::maxnum:
- 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;
- }
- }
+ if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
+ switch (II->getIntrinsicID()) {
+ // These synthetic intrinsics have no side-effects and just mark
+ // information about their operands.
+ // FIXME: There are other no-op synthetic instructions that potentially
+ // should be considered at least *safe* to speculate...
+ case Intrinsic::dbg_declare:
+ case Intrinsic::dbg_value:
+ return true;
+
+ 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;
+ // Sqrt should be OK, since the llvm sqrt intrinsic isn't defined to set
+ // errno like libm sqrt would.
+ case Intrinsic::sqrt:
+ case Intrinsic::fma:
+ case Intrinsic::fmuladd:
+ case Intrinsic::fabs:
+ case Intrinsic::minnum:
+ case Intrinsic::maxnum:
+ 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.
}
return false;
}
+
+OverflowResult llvm::computeOverflowForUnsignedMul(Value *LHS, Value *RHS,
+ const DataLayout *DL,
+ AssumptionCache *AC,
+ const Instruction *CxtI,
+ const DominatorTree *DT) {
+ // Multiplying n * m significant bits yields a result of n + m significant
+ // bits. If the total number of significant bits does not exceed the
+ // result bit width (minus 1), there is no overflow.
+ // This means if we have enough leading zero bits in the operands
+ // we can guarantee that the result does not overflow.
+ // Ref: "Hacker's Delight" by Henry Warren
+ unsigned BitWidth = LHS->getType()->getScalarSizeInBits();
+ APInt LHSKnownZero(BitWidth, 0);
+ APInt LHSKnownOne(BitWidth, 0);
+ APInt RHSKnownZero(BitWidth, 0);
+ APInt RHSKnownOne(BitWidth, 0);
+ computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, DL, /*Depth=*/0, AC, CxtI,
+ DT);
+ computeKnownBits(RHS, RHSKnownZero, RHSKnownOne, DL, /*Depth=*/0, AC, CxtI,
+ DT);
+ // Note that underestimating the number of zero bits gives a more
+ // conservative answer.
+ unsigned ZeroBits = LHSKnownZero.countLeadingOnes() +
+ RHSKnownZero.countLeadingOnes();
+ // First handle the easy case: if we have enough zero bits there's
+ // definitely no overflow.
+ if (ZeroBits >= BitWidth)
+ return OverflowResult::NeverOverflows;
+
+ // Get the largest possible values for each operand.
+ APInt LHSMax = ~LHSKnownZero;
+ APInt RHSMax = ~RHSKnownZero;
+
+ // We know the multiply operation doesn't overflow if the maximum values for
+ // each operand will not overflow after we multiply them together.
+ bool MaxOverflow;
+ LHSMax.umul_ov(RHSMax, MaxOverflow);
+ if (!MaxOverflow)
+ return OverflowResult::NeverOverflows;
+
+ // We know it always overflows if multiplying the smallest possible values for
+ // the operands also results in overflow.
+ bool MinOverflow;
+ LHSKnownOne.umul_ov(RHSKnownOne, MinOverflow);
+ if (MinOverflow)
+ return OverflowResult::AlwaysOverflows;
+
+ return OverflowResult::MayOverflow;
+}
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