//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Analysis/AssumptionTracker.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/IR/CallSite.h"
const unsigned MaxDepth = 6;
-/// getBitWidth - Returns the bitwidth of the given scalar or pointer type (if
-/// unknown returns 0). For vector types, returns the element type's bitwidth.
-static unsigned getBitWidth(Type *Ty, const DataLayout *TD) {
+/// Returns the bitwidth of the given scalar or pointer type (if unknown returns
+/// 0). For vector types, returns the element type's bitwidth.
+static unsigned getBitWidth(Type *Ty, const DataLayout &DL) {
if (unsigned BitWidth = Ty->getScalarSizeInBits())
return BitWidth;
- return TD ? TD->getPointerTypeSizeInBits(Ty) : 0;
+ return DL.getPointerTypeSizeInBits(Ty);
}
// Many of these functions have internal versions that take an assumption
// 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);
}
};
} // end anonymous namespace
-// Given the provided Value and, potentially, a context instruction, returned
+// Given the provided Value and, potentially, a context instruction, return
// the preferred context instruction (if any).
static const Instruction *safeCxtI(const Value *V, const Instruction *CxtI) {
// If we've been provided with a context instruction, then use that (provided
}
static void computeKnownBits(Value *V, APInt &KnownZero, APInt &KnownOne,
- const DataLayout *TD, unsigned Depth,
- const Query &Q);
+ const DataLayout &DL, unsigned Depth,
+ const Query &Q);
void llvm::computeKnownBits(Value *V, APInt &KnownZero, APInt &KnownOne,
- const DataLayout *TD, unsigned Depth,
- AssumptionTracker *AT, const Instruction *CxtI,
+ const DataLayout &DL, unsigned Depth,
+ AssumptionCache *AC, const Instruction *CxtI,
const DominatorTree *DT) {
- ::computeKnownBits(V, KnownZero, KnownOne, TD, Depth,
- Query(AT, safeCxtI(V, CxtI), DT));
+ ::computeKnownBits(V, KnownZero, KnownOne, DL, Depth,
+ Query(AC, safeCxtI(V, CxtI), DT));
}
static void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
- const DataLayout *TD, unsigned Depth,
- const Query &Q);
+ const DataLayout &DL, unsigned Depth,
+ const Query &Q);
void llvm::ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
- const DataLayout *TD, unsigned Depth,
- AssumptionTracker *AT, const Instruction *CxtI,
+ const DataLayout &DL, unsigned Depth,
+ AssumptionCache *AC, const Instruction *CxtI,
const DominatorTree *DT) {
- ::ComputeSignBit(V, KnownZero, KnownOne, TD, Depth,
- Query(AT, safeCxtI(V, CxtI), DT));
+ ::ComputeSignBit(V, KnownZero, KnownOne, DL, Depth,
+ Query(AC, safeCxtI(V, CxtI), DT));
}
static bool isKnownToBeAPowerOfTwo(Value *V, bool OrZero, unsigned Depth,
- const Query &Q);
+ const Query &Q, const DataLayout &DL);
-bool llvm::isKnownToBeAPowerOfTwo(Value *V, bool OrZero, unsigned Depth,
- AssumptionTracker *AT,
+bool llvm::isKnownToBeAPowerOfTwo(Value *V, const DataLayout &DL, bool OrZero,
+ unsigned Depth, 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), DL);
}
-static bool isKnownNonZero(Value *V, const DataLayout *TD, unsigned Depth,
+static bool isKnownNonZero(Value *V, const DataLayout &DL, unsigned Depth,
const Query &Q);
-bool llvm::isKnownNonZero(Value *V, const DataLayout *TD, unsigned Depth,
- AssumptionTracker *AT, const Instruction *CxtI,
+bool llvm::isKnownNonZero(Value *V, const DataLayout &DL, unsigned Depth,
+ AssumptionCache *AC, const Instruction *CxtI,
const DominatorTree *DT) {
- return ::isKnownNonZero(V, TD, Depth, Query(AT, safeCxtI(V, CxtI), DT));
+ return ::isKnownNonZero(V, DL, Depth, Query(AC, safeCxtI(V, CxtI), DT));
}
-static bool MaskedValueIsZero(Value *V, const APInt &Mask,
- const DataLayout *TD, unsigned Depth,
- const Query &Q);
+static bool MaskedValueIsZero(Value *V, const APInt &Mask, const DataLayout &DL,
+ 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) {
- return ::MaskedValueIsZero(V, Mask, TD, Depth,
- Query(AT, safeCxtI(V, CxtI), DT));
+bool llvm::MaskedValueIsZero(Value *V, const APInt &Mask, const DataLayout &DL,
+ unsigned Depth, AssumptionCache *AC,
+ const Instruction *CxtI, const DominatorTree *DT) {
+ return ::MaskedValueIsZero(V, Mask, DL, Depth,
+ Query(AC, safeCxtI(V, CxtI), DT));
}
-static unsigned ComputeNumSignBits(Value *V, const DataLayout *TD,
+static unsigned ComputeNumSignBits(Value *V, const DataLayout &DL,
unsigned Depth, const Query &Q);
-unsigned llvm::ComputeNumSignBits(Value *V, const DataLayout *TD,
- unsigned Depth, AssumptionTracker *AT,
+unsigned llvm::ComputeNumSignBits(Value *V, const DataLayout &DL,
+ unsigned Depth, AssumptionCache *AC,
const Instruction *CxtI,
const DominatorTree *DT) {
- return ::ComputeNumSignBits(V, TD, Depth, Query(AT, safeCxtI(V, CxtI), DT));
+ return ::ComputeNumSignBits(V, DL, Depth, Query(AC, safeCxtI(V, CxtI), DT));
}
static void computeKnownBitsAddSub(bool Add, Value *Op0, Value *Op1, bool NSW,
APInt &KnownZero, APInt &KnownOne,
APInt &KnownZero2, APInt &KnownOne2,
- const DataLayout *TD, unsigned Depth,
+ const DataLayout &DL, unsigned Depth,
const Query &Q) {
if (!Add) {
if (ConstantInt *CLHS = dyn_cast<ConstantInt>(Op0)) {
unsigned NLZ = (CLHS->getValue()+1).countLeadingZeros();
// NLZ can't be BitWidth with no sign bit
APInt MaskV = APInt::getHighBitsSet(BitWidth, NLZ+1);
- computeKnownBits(Op1, KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(Op1, KnownZero2, KnownOne2, DL, Depth + 1, Q);
// If all of the MaskV bits are known to be zero, then we know the
// output top bits are zero, because we now know that the output is
// If an initial sequence of bits in the result is not needed, the
// corresponding bits in the operands are not needed.
APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0);
- computeKnownBits(Op0, LHSKnownZero, LHSKnownOne, TD, Depth+1, Q);
- computeKnownBits(Op1, KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(Op0, LHSKnownZero, LHSKnownOne, DL, Depth + 1, Q);
+ computeKnownBits(Op1, KnownZero2, KnownOne2, DL, Depth + 1, Q);
// Carry in a 1 for a subtract, rather than a 0.
APInt CarryIn(BitWidth, 0);
static void computeKnownBitsMul(Value *Op0, Value *Op1, bool NSW,
APInt &KnownZero, APInt &KnownOne,
APInt &KnownZero2, APInt &KnownOne2,
- const DataLayout *TD, unsigned Depth,
+ const DataLayout &DL, unsigned Depth,
const Query &Q) {
unsigned BitWidth = KnownZero.getBitWidth();
- computeKnownBits(Op1, KnownZero, KnownOne, TD, Depth+1, Q);
- computeKnownBits(Op0, KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(Op1, KnownZero, KnownOne, DL, Depth + 1, Q);
+ computeKnownBits(Op0, KnownZero2, KnownOne2, DL, Depth + 1, Q);
bool isKnownNegative = false;
bool isKnownNonNegative = false;
// negative or zero.
if (!isKnownNonNegative)
isKnownNegative = (isKnownNegativeOp1 && isKnownNonNegativeOp0 &&
- isKnownNonZero(Op0, TD, Depth, Q)) ||
+ isKnownNonZero(Op0, DL, Depth, Q)) ||
(isKnownNegativeOp0 && isKnownNonNegativeOp1 &&
- isKnownNonZero(Op1, TD, Depth, Q));
+ isKnownNonZero(Op1, DL, Depth, Q));
}
}
// 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.
return false;
}
-static bool isValidAssumeForContext(Value *V, const Query &Q,
- const DataLayout *DL) {
+static bool isValidAssumeForContext(Value *V, const Query &Q) {
Instruction *Inv = cast<Instruction>(V);
// There are two restrictions on the use of an assume:
for (BasicBlock::const_iterator I =
std::next(BasicBlock::const_iterator(Q.CxtI)),
IE(Inv); I != IE; ++I)
- if (!isSafeToSpeculativelyExecute(I, DL) &&
- !isAssumeLikeIntrinsic(I))
+ if (!isSafeToSpeculativelyExecute(I) && !isAssumeLikeIntrinsic(I))
return false;
return !isEphemeralValueOf(Inv, Q.CxtI);
for (BasicBlock::const_iterator I =
std::next(BasicBlock::const_iterator(Q.CxtI)),
IE(Inv); I != IE; ++I)
- if (!isSafeToSpeculativelyExecute(I, DL) &&
- !isAssumeLikeIntrinsic(I))
+ if (!isSafeToSpeculativelyExecute(I) && !isAssumeLikeIntrinsic(I))
return false;
return !isEphemeralValueOf(Inv, Q.CxtI);
bool llvm::isValidAssumeForContext(const Instruction *I,
const Instruction *CxtI,
- const DataLayout *DL,
const DominatorTree *DT) {
- return ::isValidAssumeForContext(const_cast<Instruction*>(I),
- Query(nullptr, CxtI, DT), DL);
+ return ::isValidAssumeForContext(const_cast<Instruction *>(I),
+ Query(nullptr, CxtI, DT));
}
template<typename LHS, typename RHS>
}
static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero,
- APInt &KnownOne,
- const DataLayout *DL,
+ APInt &KnownOne, const DataLayout &DL,
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() == Q.CxtI->getParent()->getParent() &&
+ "Got assumption for the wrong function!");
if (Q.ExclInvs.count(I))
continue;
- if (match(I, m_Intrinsic<Intrinsic::assume>(m_Specific(V))) &&
- isValidAssumeForContext(I, Q, DL)) {
+ // 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)) {
assert(BitWidth == 1 && "assume operand is not i1?");
KnownZero.clearAllBits();
KnownOne.setAllBits();
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ if (match(Arg, m_c_ICmp(Pred, m_V, m_Value(A))) &&
+ Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q)) {
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
APInt MaskKnownZero(BitWidth, 0), MaskKnownOne(BitWidth, 0);
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
APInt MaskKnownZero(BitWidth, 0), MaskKnownOne(BitWidth, 0);
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
APInt BKnownZero(BitWidth, 0), BKnownOne(BitWidth, 0);
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
APInt BKnownZero(BitWidth, 0), BKnownOne(BitWidth, 0);
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
APInt BKnownZero(BitWidth, 0), BKnownOne(BitWidth, 0);
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
APInt BKnownZero(BitWidth, 0), BKnownOne(BitWidth, 0);
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
// For those bits in RHS that are known, we can propagate them to known
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)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
// For those bits in RHS that are known, we can propagate them inverted
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)),
- m_AShr(m_V,
- m_ConstantInt(C))),
- m_Value(A)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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))) &&
+ Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
// For those bits in RHS that are known, we can propagate them to known
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(
- m_LShr(m_V, m_ConstantInt(C)),
- m_AShr(m_V, m_ConstantInt(C)))),
- m_Value(A)))) &&
- Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) {
+ } 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))) &&
+ Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
// For those bits in RHS that are known, we can propagate them inverted
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)))) &&
- Pred == ICmpInst::ICMP_SGE &&
- isValidAssumeForContext(I, Q, DL)) {
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
+ Pred == ICmpInst::ICMP_SGE && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
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)))) &&
- Pred == ICmpInst::ICMP_SGT &&
- isValidAssumeForContext(I, Q, DL)) {
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
+ Pred == ICmpInst::ICMP_SGT && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
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)))) &&
- Pred == ICmpInst::ICMP_SLE &&
- isValidAssumeForContext(I, Q, DL)) {
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
+ Pred == ICmpInst::ICMP_SLE && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
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)))) &&
- Pred == ICmpInst::ICMP_SLT &&
- isValidAssumeForContext(I, Q, DL)) {
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
+ Pred == ICmpInst::ICMP_SLT && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
KnownOne |= APInt::getSignBit(BitWidth);
}
// assume(v <=_u c)
- } else if (match(I, m_Intrinsic<Intrinsic::assume>(
- m_ICmp(Pred, m_V, m_Value(A)))) &&
- Pred == ICmpInst::ICMP_ULE &&
- isValidAssumeForContext(I, Q, DL)) {
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
+ Pred == ICmpInst::ICMP_ULE && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
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)))) &&
- Pred == ICmpInst::ICMP_ULT &&
- isValidAssumeForContext(I, Q, DL)) {
+ } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) &&
+ Pred == ICmpInst::ICMP_ULT && isValidAssumeForContext(I, Q)) {
APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);
computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I));
// Whatever high bits in c are zero are known to be zero (if c is a power
// of 2, then one more).
- if (isKnownToBeAPowerOfTwo(A, false, Depth+1, Query(Q, I)))
+ if (isKnownToBeAPowerOfTwo(A, false, Depth + 1, Query(Q, I), DL))
KnownZero |=
APInt::getHighBitsSet(BitWidth, RHSKnownZero.countLeadingOnes()+1);
else
/// this won't lose us code quality.
///
/// This function is defined on values with integer type, values with pointer
-/// type (but only if TD is non-null), and vectors of integers. In the case
+/// type, and vectors of integers. In the case
/// where V is a vector, known zero, and known one values are the
/// same width as the vector element, and the bit is set only if it is true
/// for all of the elements in the vector.
void computeKnownBits(Value *V, APInt &KnownZero, APInt &KnownOne,
- const DataLayout *TD, unsigned Depth,
- const Query &Q) {
+ const DataLayout &DL, unsigned Depth, const Query &Q) {
assert(V && "No Value?");
assert(Depth <= MaxDepth && "Limit Search Depth");
unsigned BitWidth = KnownZero.getBitWidth();
assert((V->getType()->isIntOrIntVectorTy() ||
V->getType()->getScalarType()->isPointerTy()) &&
"Not integer or pointer type!");
- assert((!TD ||
- TD->getTypeSizeInBits(V->getType()->getScalarType()) == BitWidth) &&
+ assert((DL.getTypeSizeInBits(V->getType()->getScalarType()) == BitWidth) &&
(!V->getType()->isIntOrIntVectorTy() ||
V->getType()->getScalarSizeInBits() == BitWidth) &&
KnownZero.getBitWidth() == BitWidth &&
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 (Align == 0 && TD) {
- if (GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
+ if (auto *GO = dyn_cast<GlobalObject>(V)) {
+ unsigned Align = GO->getAlignment();
+ if (Align == 0) {
+ 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
// it the preferred alignment. Otherwise, we have to assume that it
// may only have the minimum ABI alignment.
if (!GVar->isDeclaration() && !GVar->isWeakForLinker())
- Align = TD->getPreferredAlignment(GVar);
+ Align = DL.getPreferredAlignment(GVar);
else
- Align = TD->getABITypeAlignment(ObjectType);
+ Align = DL.getABITypeAlignment(ObjectType);
}
}
}
if (Argument *A = dyn_cast<Argument>(V)) {
unsigned Align = A->getType()->isPointerTy() ? A->getParamAlignment() : 0;
- if (!Align && TD && A->hasStructRetAttr()) {
+ if (!Align && A->hasStructRetAttr()) {
// An sret parameter has at least the ABI alignment of the return type.
Type *EltTy = cast<PointerType>(A->getType())->getElementType();
if (EltTy->isSized())
- Align = TD->getABITypeAlignment(EltTy);
+ Align = DL.getABITypeAlignment(EltTy);
}
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...
- computeKnownBitsFromAssume(V, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBitsFromAssume(V, KnownZero, KnownOne, DL, Depth, Q);
return;
}
// 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, DL, Depth + 1, Q);
+ return;
+ }
// Check whether a nearby assume intrinsic can determine some known bits.
- computeKnownBitsFromAssume(V, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBitsFromAssume(V, KnownZero, KnownOne, DL, Depth, Q);
Operator *I = dyn_cast<Operator>(V);
if (!I) return;
break;
case Instruction::And: {
// If either the LHS or the RHS are Zero, the result is zero.
- computeKnownBits(I->getOperand(1), KnownZero, KnownOne, TD, Depth+1, Q);
- computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(1), KnownZero, KnownOne, DL, Depth + 1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, DL, Depth + 1, Q);
// Output known-1 bits are only known if set in both the LHS & RHS.
KnownOne &= KnownOne2;
break;
}
case Instruction::Or: {
- computeKnownBits(I->getOperand(1), KnownZero, KnownOne, TD, Depth+1, Q);
- computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(1), KnownZero, KnownOne, DL, Depth + 1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, DL, Depth + 1, Q);
// Output known-0 bits are only known if clear in both the LHS & RHS.
KnownZero &= KnownZero2;
break;
}
case Instruction::Xor: {
- computeKnownBits(I->getOperand(1), KnownZero, KnownOne, TD, Depth+1, Q);
- computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(1), KnownZero, KnownOne, DL, Depth + 1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, DL, Depth + 1, Q);
// Output known-0 bits are known if clear or set in both the LHS & RHS.
APInt KnownZeroOut = (KnownZero & KnownZero2) | (KnownOne & KnownOne2);
}
case Instruction::Mul: {
bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap();
- computeKnownBitsMul(I->getOperand(0), I->getOperand(1), NSW,
- KnownZero, KnownOne, KnownZero2, KnownOne2, TD,
- Depth, Q);
+ computeKnownBitsMul(I->getOperand(0), I->getOperand(1), NSW, KnownZero,
+ KnownOne, KnownZero2, KnownOne2, DL, Depth, Q);
break;
}
case Instruction::UDiv: {
// For the purposes of computing leading zeros we can conservatively
// treat a udiv as a logical right shift by the power of 2 known to
// be less than the denominator.
- computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, DL, Depth + 1, Q);
unsigned LeadZ = KnownZero2.countLeadingOnes();
KnownOne2.clearAllBits();
KnownZero2.clearAllBits();
- computeKnownBits(I->getOperand(1), KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(1), KnownZero2, KnownOne2, DL, Depth + 1, Q);
unsigned RHSUnknownLeadingOnes = KnownOne2.countLeadingZeros();
if (RHSUnknownLeadingOnes != BitWidth)
LeadZ = std::min(BitWidth,
break;
}
case Instruction::Select:
- computeKnownBits(I->getOperand(2), KnownZero, KnownOne, TD, Depth+1, Q);
- computeKnownBits(I->getOperand(1), KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(2), KnownZero, KnownOne, DL, Depth + 1, Q);
+ computeKnownBits(I->getOperand(1), KnownZero2, KnownOne2, DL, Depth + 1, Q);
// Only known if known in both the LHS and RHS.
KnownOne &= KnownOne2;
case Instruction::PtrToInt:
case Instruction::IntToPtr:
case Instruction::AddrSpaceCast: // Pointers could be different sizes.
- // We can't handle these if we don't know the pointer size.
- if (!TD) break;
// FALL THROUGH and handle them the same as zext/trunc.
case Instruction::ZExt:
case Instruction::Trunc: {
unsigned SrcBitWidth;
// Note that we handle pointer operands here because of inttoptr/ptrtoint
// which fall through here.
- if(TD) {
- SrcBitWidth = TD->getTypeSizeInBits(SrcTy->getScalarType());
- } else {
- SrcBitWidth = SrcTy->getScalarSizeInBits();
- if (!SrcBitWidth) break;
- }
+ SrcBitWidth = DL.getTypeSizeInBits(SrcTy->getScalarType());
assert(SrcBitWidth && "SrcBitWidth can't be zero");
KnownZero = KnownZero.zextOrTrunc(SrcBitWidth);
KnownOne = KnownOne.zextOrTrunc(SrcBitWidth);
- computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, DL, Depth + 1, Q);
KnownZero = KnownZero.zextOrTrunc(BitWidth);
KnownOne = KnownOne.zextOrTrunc(BitWidth);
// Any top bits are known to be zero.
// TODO: For now, not handling conversions like:
// (bitcast i64 %x to <2 x i32>)
!I->getType()->isVectorTy()) {
- computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, DL, Depth + 1, Q);
break;
}
break;
KnownZero = KnownZero.trunc(SrcBitWidth);
KnownOne = KnownOne.trunc(SrcBitWidth);
- computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, DL, Depth + 1, Q);
KnownZero = KnownZero.zext(BitWidth);
KnownOne = KnownOne.zext(BitWidth);
// (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0
if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) {
uint64_t ShiftAmt = SA->getLimitedValue(BitWidth);
- computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, DL, Depth + 1, Q);
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, DL, 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:
uint64_t ShiftAmt = SA->getLimitedValue(BitWidth-1);
// Signed shift right.
- computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, DL, Depth + 1, Q);
KnownZero = APIntOps::lshr(KnownZero, ShiftAmt);
KnownOne = APIntOps::lshr(KnownOne, ShiftAmt);
KnownZero |= HighBits;
else if (KnownOne[BitWidth-ShiftAmt-1]) // New bits are known one.
KnownOne |= HighBits;
- break;
}
break;
case Instruction::Sub: {
bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap();
computeKnownBitsAddSub(false, I->getOperand(0), I->getOperand(1), NSW,
- KnownZero, KnownOne, KnownZero2, KnownOne2, TD,
- Depth, Q);
+ KnownZero, KnownOne, KnownZero2, KnownOne2, DL,
+ Depth, Q);
break;
}
case Instruction::Add: {
bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap();
computeKnownBitsAddSub(true, I->getOperand(0), I->getOperand(1), NSW,
- KnownZero, KnownOne, KnownZero2, KnownOne2, TD,
- Depth, Q);
+ KnownZero, KnownOne, KnownZero2, KnownOne2, DL,
+ Depth, Q);
break;
}
case Instruction::SRem:
APInt RA = Rem->getValue().abs();
if (RA.isPowerOf2()) {
APInt LowBits = RA - 1;
- computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, TD,
- Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero2, KnownOne2, DL, Depth + 1,
+ Q);
// The low bits of the first operand are unchanged by the srem.
KnownZero = KnownZero2 & LowBits;
// remainder is zero.
if (KnownZero.isNonNegative()) {
APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0);
- computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, TD,
- Depth+1, Q);
+ computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, DL,
+ Depth + 1, Q);
// If it's known zero, our sign bit is also zero.
if (LHSKnownZero.isNegative())
KnownZero.setBit(BitWidth - 1);
APInt RA = Rem->getValue();
if (RA.isPowerOf2()) {
APInt LowBits = (RA - 1);
- computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD,
- Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, DL, Depth + 1,
+ Q);
KnownZero |= ~LowBits;
KnownOne &= LowBits;
break;
// Since the result is less than or equal to either operand, any leading
// zero bits in either operand must also exist in the result.
- computeKnownBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1, Q);
- computeKnownBits(I->getOperand(1), KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(I->getOperand(0), KnownZero, KnownOne, DL, Depth + 1, Q);
+ computeKnownBits(I->getOperand(1), KnownZero2, KnownOne2, DL, Depth + 1, Q);
unsigned Leaders = std::max(KnownZero.countLeadingOnes(),
KnownZero2.countLeadingOnes());
case Instruction::Alloca: {
AllocaInst *AI = cast<AllocaInst>(V);
unsigned Align = AI->getAlignment();
- if (Align == 0 && TD)
- Align = TD->getABITypeAlignment(AI->getType()->getElementType());
+ if (Align == 0)
+ Align = DL.getABITypeAlignment(AI->getType()->getElementType());
if (Align > 0)
KnownZero = APInt::getLowBitsSet(BitWidth, countTrailingZeros(Align));
// Analyze all of the subscripts of this getelementptr instruction
// to determine if we can prove known low zero bits.
APInt LocalKnownZero(BitWidth, 0), LocalKnownOne(BitWidth, 0);
- computeKnownBits(I->getOperand(0), LocalKnownZero, LocalKnownOne, TD,
- Depth+1, Q);
+ computeKnownBits(I->getOperand(0), LocalKnownZero, LocalKnownOne, DL,
+ Depth + 1, Q);
unsigned TrailZ = LocalKnownZero.countTrailingOnes();
gep_type_iterator GTI = gep_type_begin(I);
Value *Index = I->getOperand(i);
if (StructType *STy = dyn_cast<StructType>(*GTI)) {
// Handle struct member offset arithmetic.
- if (!TD) {
- TrailZ = 0;
- break;
- }
// Handle case when index is vector zeroinitializer
Constant *CIndex = cast<Constant>(Index);
Index = CIndex->getSplatValue();
unsigned Idx = cast<ConstantInt>(Index)->getZExtValue();
- const StructLayout *SL = TD->getStructLayout(STy);
+ const StructLayout *SL = DL.getStructLayout(STy);
uint64_t Offset = SL->getElementOffset(Idx);
TrailZ = std::min<unsigned>(TrailZ,
countTrailingZeros(Offset));
break;
}
unsigned GEPOpiBits = Index->getType()->getScalarSizeInBits();
- uint64_t TypeSize = TD ? TD->getTypeAllocSize(IndexedTy) : 1;
+ uint64_t TypeSize = DL.getTypeAllocSize(IndexedTy);
LocalKnownZero = LocalKnownOne = APInt(GEPOpiBits, 0);
- computeKnownBits(Index, LocalKnownZero, LocalKnownOne, TD, Depth+1, Q);
+ computeKnownBits(Index, LocalKnownZero, LocalKnownOne, DL, Depth + 1,
+ Q);
TrailZ = std::min(TrailZ,
unsigned(countTrailingZeros(TypeSize) +
LocalKnownZero.countTrailingOnes()));
break;
// Ok, we have a PHI of the form L op= R. Check for low
// zero bits.
- computeKnownBits(R, KnownZero2, KnownOne2, TD, Depth+1, Q);
+ computeKnownBits(R, KnownZero2, KnownOne2, DL, Depth + 1, Q);
// We need to take the minimum number of known bits
APInt KnownZero3(KnownZero), KnownOne3(KnownOne);
- computeKnownBits(L, KnownZero3, KnownOne3, TD, Depth+1, Q);
+ computeKnownBits(L, KnownZero3, KnownOne3, DL, Depth + 1, Q);
KnownZero = APInt::getLowBitsSet(BitWidth,
std::min(KnownZero2.countTrailingOnes(),
KnownOne2 = APInt(BitWidth, 0);
// Recurse, but cap the recursion to one level, because we don't
// want to waste time spinning around in loops.
- computeKnownBits(P->getIncomingValue(i), KnownZero2, KnownOne2, TD,
- MaxDepth-1, Q);
+ computeKnownBits(P->getIncomingValue(i), KnownZero2, KnownOne2, DL,
+ MaxDepth - 1, Q);
KnownZero &= KnownZero2;
KnownOne &= KnownOne2;
// If all bits have been ruled out, there's no need to check
case Intrinsic::sadd_with_overflow:
computeKnownBitsAddSub(true, II->getArgOperand(0),
II->getArgOperand(1), false, KnownZero,
- KnownOne, KnownZero2, KnownOne2, TD, Depth, Q);
+ KnownOne, KnownZero2, KnownOne2, DL, Depth, Q);
break;
case Intrinsic::usub_with_overflow:
case Intrinsic::ssub_with_overflow:
computeKnownBitsAddSub(false, II->getArgOperand(0),
II->getArgOperand(1), false, KnownZero,
- KnownOne, KnownZero2, KnownOne2, TD, Depth, Q);
+ KnownOne, KnownZero2, KnownOne2, DL, Depth, Q);
break;
case Intrinsic::umul_with_overflow:
case Intrinsic::smul_with_overflow:
- computeKnownBitsMul(II->getArgOperand(0), II->getArgOperand(1),
- false, KnownZero, KnownOne,
- KnownZero2, KnownOne2, TD, Depth, Q);
+ computeKnownBitsMul(II->getArgOperand(0), II->getArgOperand(1), false,
+ KnownZero, KnownOne, KnownZero2, KnownOne2, DL,
+ Depth, Q);
break;
}
}
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
}
-/// ComputeSignBit - Determine whether the sign bit is known to be zero or
-/// one. Convenience wrapper around computeKnownBits.
+/// Determine whether the sign bit is known to be zero or one.
+/// Convenience wrapper around computeKnownBits.
void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
- const DataLayout *TD, unsigned Depth,
- const Query &Q) {
- unsigned BitWidth = getBitWidth(V->getType(), TD);
+ const DataLayout &DL, unsigned Depth, const Query &Q) {
+ unsigned BitWidth = getBitWidth(V->getType(), DL);
if (!BitWidth) {
KnownZero = false;
KnownOne = false;
}
APInt ZeroBits(BitWidth, 0);
APInt OneBits(BitWidth, 0);
- computeKnownBits(V, ZeroBits, OneBits, TD, Depth, Q);
+ computeKnownBits(V, ZeroBits, OneBits, DL, Depth, Q);
KnownOne = OneBits[BitWidth - 1];
KnownZero = ZeroBits[BitWidth - 1];
}
-/// isKnownToBeAPowerOfTwo - Return true if the given value is known to have exactly one
+/// Return true if the given value is known to have exactly one
/// bit set when defined. For vectors return true if every element is known to
-/// be a power of two when defined. Supports values with integer or pointer
+/// be a power of two when defined. Supports values with integer or pointer
/// types and vectors of integers.
bool isKnownToBeAPowerOfTwo(Value *V, bool OrZero, unsigned Depth,
- const Query &Q) {
+ const Query &Q, const DataLayout &DL) {
if (Constant *C = dyn_cast<Constant>(V)) {
if (C->isNullValue())
return OrZero;
// A shift of a power of two is a power of two or zero.
if (OrZero && (match(V, m_Shl(m_Value(X), m_Value())) ||
match(V, m_Shr(m_Value(X), m_Value()))))
- return isKnownToBeAPowerOfTwo(X, /*OrZero*/true, Depth, Q);
+ return isKnownToBeAPowerOfTwo(X, /*OrZero*/ true, Depth, Q, DL);
if (ZExtInst *ZI = dyn_cast<ZExtInst>(V))
- return isKnownToBeAPowerOfTwo(ZI->getOperand(0), OrZero, Depth, Q);
+ return isKnownToBeAPowerOfTwo(ZI->getOperand(0), OrZero, Depth, Q, DL);
if (SelectInst *SI = dyn_cast<SelectInst>(V))
- return
- isKnownToBeAPowerOfTwo(SI->getTrueValue(), OrZero, Depth, Q) &&
- isKnownToBeAPowerOfTwo(SI->getFalseValue(), OrZero, Depth, Q);
+ return isKnownToBeAPowerOfTwo(SI->getTrueValue(), OrZero, Depth, Q, DL) &&
+ isKnownToBeAPowerOfTwo(SI->getFalseValue(), OrZero, Depth, Q, DL);
if (OrZero && match(V, m_And(m_Value(X), m_Value(Y)))) {
// A power of two and'd with anything is a power of two or zero.
- if (isKnownToBeAPowerOfTwo(X, /*OrZero*/true, Depth, Q) ||
- isKnownToBeAPowerOfTwo(Y, /*OrZero*/true, Depth, Q))
+ if (isKnownToBeAPowerOfTwo(X, /*OrZero*/ true, Depth, Q, DL) ||
+ isKnownToBeAPowerOfTwo(Y, /*OrZero*/ true, Depth, Q, DL))
return true;
// X & (-X) is always a power of two or zero.
if (match(X, m_Neg(m_Specific(Y))) || match(Y, m_Neg(m_Specific(X))))
if (OrZero || VOBO->hasNoUnsignedWrap() || VOBO->hasNoSignedWrap()) {
if (match(X, m_And(m_Specific(Y), m_Value())) ||
match(X, m_And(m_Value(), m_Specific(Y))))
- if (isKnownToBeAPowerOfTwo(Y, OrZero, Depth, Q))
+ if (isKnownToBeAPowerOfTwo(Y, OrZero, Depth, Q, DL))
return true;
if (match(Y, m_And(m_Specific(X), m_Value())) ||
match(Y, m_And(m_Value(), m_Specific(X))))
- if (isKnownToBeAPowerOfTwo(X, OrZero, Depth, Q))
+ if (isKnownToBeAPowerOfTwo(X, OrZero, Depth, Q, DL))
return true;
unsigned BitWidth = V->getType()->getScalarSizeInBits();
APInt LHSZeroBits(BitWidth, 0), LHSOneBits(BitWidth, 0);
- computeKnownBits(X, LHSZeroBits, LHSOneBits, nullptr, Depth, Q);
+ computeKnownBits(X, LHSZeroBits, LHSOneBits, DL, Depth, Q);
APInt RHSZeroBits(BitWidth, 0), RHSOneBits(BitWidth, 0);
- computeKnownBits(Y, RHSZeroBits, RHSOneBits, nullptr, Depth, Q);
+ computeKnownBits(Y, RHSZeroBits, RHSOneBits, DL, Depth, Q);
// If i8 V is a power of two or zero:
// ZeroBits: 1 1 1 0 1 1 1 1
// ~ZeroBits: 0 0 0 1 0 0 0 0
if (match(V, m_Exact(m_LShr(m_Value(), m_Value()))) ||
match(V, m_Exact(m_UDiv(m_Value(), m_Value())))) {
return isKnownToBeAPowerOfTwo(cast<Operator>(V)->getOperand(0), OrZero,
- Depth, Q);
+ Depth, Q, DL);
}
return false;
/// to be non-null.
///
/// Currently this routine does not support vector GEPs.
-static bool isGEPKnownNonNull(GEPOperator *GEP, const DataLayout *DL,
+static bool isGEPKnownNonNull(GEPOperator *GEP, const DataLayout &DL,
unsigned Depth, const Query &Q) {
if (!GEP->isInBounds() || GEP->getPointerAddressSpace() != 0)
return false;
if (isKnownNonZero(GEP->getPointerOperand(), DL, Depth, Q))
return true;
- // Past this, if we don't have DataLayout, we can't do much.
- if (!DL)
- return false;
-
// Walk the GEP operands and see if any operand introduces a non-zero offset.
// If so, then the GEP cannot produce a null pointer, as doing so would
// inherently violate the inbounds contract within address space zero.
if (StructType *STy = dyn_cast<StructType>(*GTI)) {
ConstantInt *OpC = cast<ConstantInt>(GTI.getOperand());
unsigned ElementIdx = OpC->getZExtValue();
- const StructLayout *SL = DL->getStructLayout(STy);
+ const StructLayout *SL = DL.getStructLayout(STy);
uint64_t ElementOffset = SL->getElementOffset(ElementIdx);
if (ElementOffset > 0)
return true;
}
// If we have a zero-sized type, the index doesn't matter. Keep looping.
- if (DL->getTypeAllocSize(GTI.getIndexedType()) == 0)
+ if (DL.getTypeAllocSize(GTI.getIndexedType()) == 0)
continue;
// Fast path the constant operand case both for efficiency and so we don't
return false;
}
-/// isKnownNonZero - Return true if the given value is known to be non-zero
-/// when defined. For vectors return true if every element is known to be
-/// non-zero when defined. Supports values with integer or pointer type and
-/// vectors of integers.
-bool isKnownNonZero(Value *V, const DataLayout *TD, unsigned Depth,
+/// Does the 'Range' metadata (which must be a valid MD_range operand list)
+/// ensure that the value it's attached to is never Value? 'RangeType' is
+/// is the type of the value described by the range.
+static bool rangeMetadataExcludesValue(MDNode* Ranges,
+ const APInt& Value) {
+ const unsigned NumRanges = Ranges->getNumOperands() / 2;
+ assert(NumRanges >= 1);
+ for (unsigned i = 0; i < NumRanges; ++i) {
+ 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;
+ }
+ return true;
+}
+
+/// Return true if the given value is known to be non-zero when defined.
+/// For vectors return true if every element is known to be non-zero when
+/// defined. Supports values with integer or pointer type and vectors of
+/// integers.
+bool isKnownNonZero(Value *V, const DataLayout &DL, unsigned Depth,
const Query &Q) {
if (Constant *C = dyn_cast<Constant>(V)) {
if (C->isNullValue())
return false;
}
+ if (Instruction* I = dyn_cast<Instruction>(V)) {
+ 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())) {
+ const APInt ZeroValue(Ty->getBitWidth(), 0);
+ if (rangeMetadataExcludesValue(Ranges, ZeroValue))
+ return true;
+ }
+ }
+ }
+
// The remaining tests are all recursive, so bail out if we hit the limit.
if (Depth++ >= MaxDepth)
return false;
if (isKnownNonNull(V))
return true;
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
- if (isGEPKnownNonNull(GEP, TD, Depth, Q))
+ if (isGEPKnownNonNull(GEP, DL, Depth, Q))
return true;
}
- unsigned BitWidth = getBitWidth(V->getType()->getScalarType(), TD);
+ unsigned BitWidth = getBitWidth(V->getType()->getScalarType(), DL);
// X | Y != 0 if X != 0 or Y != 0.
Value *X = nullptr, *Y = nullptr;
if (match(V, m_Or(m_Value(X), m_Value(Y))))
- return isKnownNonZero(X, TD, Depth, Q) ||
- isKnownNonZero(Y, TD, Depth, Q);
+ return isKnownNonZero(X, DL, Depth, Q) || isKnownNonZero(Y, DL, Depth, Q);
// ext X != 0 if X != 0.
if (isa<SExtInst>(V) || isa<ZExtInst>(V))
- return isKnownNonZero(cast<Instruction>(V)->getOperand(0), TD, Depth, Q);
+ return isKnownNonZero(cast<Instruction>(V)->getOperand(0), DL, Depth, Q);
// shl X, Y != 0 if X is odd. Note that the value of the shift is undefined
// if the lowest bit is shifted off the end.
// shl nuw can't remove any non-zero bits.
OverflowingBinaryOperator *BO = cast<OverflowingBinaryOperator>(V);
if (BO->hasNoUnsignedWrap())
- return isKnownNonZero(X, TD, Depth, Q);
+ return isKnownNonZero(X, DL, Depth, Q);
APInt KnownZero(BitWidth, 0);
APInt KnownOne(BitWidth, 0);
- computeKnownBits(X, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBits(X, KnownZero, KnownOne, DL, Depth, Q);
if (KnownOne[0])
return true;
}
// shr exact can only shift out zero bits.
PossiblyExactOperator *BO = cast<PossiblyExactOperator>(V);
if (BO->isExact())
- return isKnownNonZero(X, TD, Depth, Q);
+ return isKnownNonZero(X, DL, Depth, Q);
bool XKnownNonNegative, XKnownNegative;
- ComputeSignBit(X, XKnownNonNegative, XKnownNegative, TD, Depth, Q);
+ ComputeSignBit(X, XKnownNonNegative, XKnownNegative, DL, Depth, Q);
if (XKnownNegative)
return true;
}
// div exact can only produce a zero if the dividend is zero.
else if (match(V, m_Exact(m_IDiv(m_Value(X), m_Value())))) {
- return isKnownNonZero(X, TD, Depth, Q);
+ return isKnownNonZero(X, DL, Depth, Q);
}
// X + Y.
else if (match(V, m_Add(m_Value(X), m_Value(Y)))) {
bool XKnownNonNegative, XKnownNegative;
bool YKnownNonNegative, YKnownNegative;
- ComputeSignBit(X, XKnownNonNegative, XKnownNegative, TD, Depth, Q);
- ComputeSignBit(Y, YKnownNonNegative, YKnownNegative, TD, Depth, Q);
+ ComputeSignBit(X, XKnownNonNegative, XKnownNegative, DL, Depth, Q);
+ ComputeSignBit(Y, YKnownNonNegative, YKnownNegative, DL, Depth, Q);
// If X and Y are both non-negative (as signed values) then their sum is not
// zero unless both X and Y are zero.
if (XKnownNonNegative && YKnownNonNegative)
- if (isKnownNonZero(X, TD, Depth, Q) ||
- isKnownNonZero(Y, TD, Depth, Q))
+ if (isKnownNonZero(X, DL, Depth, Q) || isKnownNonZero(Y, DL, Depth, Q))
return true;
// If X and Y are both negative (as signed values) then their sum is not
APInt Mask = APInt::getSignedMaxValue(BitWidth);
// The sign bit of X is set. If some other bit is set then X is not equal
// to INT_MIN.
- computeKnownBits(X, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBits(X, KnownZero, KnownOne, DL, Depth, Q);
if ((KnownOne & Mask) != 0)
return true;
// The sign bit of Y is set. If some other bit is set then Y is not equal
// to INT_MIN.
- computeKnownBits(Y, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBits(Y, KnownZero, KnownOne, DL, Depth, Q);
if ((KnownOne & Mask) != 0)
return true;
}
// The sum of a non-negative number and a power of two is not zero.
if (XKnownNonNegative &&
- isKnownToBeAPowerOfTwo(Y, /*OrZero*/false, Depth, Q))
+ isKnownToBeAPowerOfTwo(Y, /*OrZero*/ false, Depth, Q, DL))
return true;
if (YKnownNonNegative &&
- isKnownToBeAPowerOfTwo(X, /*OrZero*/false, Depth, Q))
+ isKnownToBeAPowerOfTwo(X, /*OrZero*/ false, Depth, Q, DL))
return true;
}
// X * Y.
// If X and Y are non-zero then so is X * Y as long as the multiplication
// does not overflow.
if ((BO->hasNoSignedWrap() || BO->hasNoUnsignedWrap()) &&
- isKnownNonZero(X, TD, Depth, Q) &&
- isKnownNonZero(Y, TD, Depth, Q))
+ isKnownNonZero(X, DL, Depth, Q) && isKnownNonZero(Y, DL, Depth, Q))
return true;
}
// (C ? X : Y) != 0 if X != 0 and Y != 0.
else if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
- if (isKnownNonZero(SI->getTrueValue(), TD, Depth, Q) &&
- isKnownNonZero(SI->getFalseValue(), TD, Depth, Q))
+ if (isKnownNonZero(SI->getTrueValue(), DL, Depth, Q) &&
+ isKnownNonZero(SI->getFalseValue(), DL, Depth, Q))
return true;
}
if (!BitWidth) return false;
APInt KnownZero(BitWidth, 0);
APInt KnownOne(BitWidth, 0);
- computeKnownBits(V, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBits(V, KnownZero, KnownOne, DL, Depth, Q);
return KnownOne != 0;
}
-/// MaskedValueIsZero - Return true if 'V & Mask' is known to be zero. We use
-/// this predicate to simplify operations downstream. Mask is known to be zero
-/// for bits that V cannot have.
+/// Return true if 'V & Mask' is known to be zero. We use this predicate to
+/// simplify operations downstream. Mask is known to be zero for bits that V
+/// cannot have.
///
/// This function is defined on values with integer type, values with pointer
-/// type (but only if TD is non-null), and vectors of integers. In the case
+/// type, and vectors of integers. In the case
/// where V is a vector, the mask, known zero, and known one values are the
/// same width as the vector element, and the bit is set only if it is true
/// for all of the elements in the vector.
-bool MaskedValueIsZero(Value *V, const APInt &Mask,
- const DataLayout *TD, unsigned Depth,
- const Query &Q) {
+bool MaskedValueIsZero(Value *V, const APInt &Mask, const DataLayout &DL,
+ unsigned Depth, const Query &Q) {
APInt KnownZero(Mask.getBitWidth(), 0), KnownOne(Mask.getBitWidth(), 0);
- computeKnownBits(V, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBits(V, KnownZero, KnownOne, DL, Depth, Q);
return (KnownZero & Mask) == Mask;
}
-/// ComputeNumSignBits - Return the number of times the sign bit of the
-/// register is replicated into the other bits. We know that at least 1 bit
-/// is always equal to the sign bit (itself), but other cases can give us
-/// information. For example, immediately after an "ashr X, 2", we know that
-/// the top 3 bits are all equal to each other, so we return 3.
+/// Return the number of times the sign bit of the register is replicated into
+/// the other bits. We know that at least 1 bit is always equal to the sign bit
+/// (itself), but other cases can give us information. For example, immediately
+/// after an "ashr X, 2", we know that the top 3 bits are all equal to each
+/// other, so we return 3.
///
/// 'Op' must have a scalar integer type.
///
-unsigned ComputeNumSignBits(Value *V, const DataLayout *TD,
- unsigned Depth, const Query &Q) {
- assert((TD || V->getType()->isIntOrIntVectorTy()) &&
- "ComputeNumSignBits requires a DataLayout object to operate "
- "on non-integer values!");
- Type *Ty = V->getType();
- unsigned TyBits = TD ? TD->getTypeSizeInBits(V->getType()->getScalarType()) :
- Ty->getScalarSizeInBits();
+unsigned ComputeNumSignBits(Value *V, const DataLayout &DL, unsigned Depth,
+ const Query &Q) {
+ unsigned TyBits = DL.getTypeSizeInBits(V->getType()->getScalarType());
unsigned Tmp, Tmp2;
unsigned FirstAnswer = 1;
default: break;
case Instruction::SExt:
Tmp = TyBits - U->getOperand(0)->getType()->getScalarSizeInBits();
- return ComputeNumSignBits(U->getOperand(0), TD, Depth+1, Q) + Tmp;
+ return ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q) + Tmp;
+
+ case Instruction::SDiv: {
+ const APInt *Denominator;
+ // sdiv X, C -> adds log(C) sign bits.
+ if (match(U->getOperand(1), m_APInt(Denominator))) {
+
+ // Ignore non-positive denominator.
+ if (!Denominator->isStrictlyPositive())
+ break;
+
+ // Calculate the incoming numerator bits.
+ unsigned NumBits = ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q);
+
+ // Add floor(log(C)) bits to the numerator bits.
+ return std::min(TyBits, NumBits + Denominator->logBase2());
+ }
+ break;
+ }
+
+ case Instruction::SRem: {
+ const APInt *Denominator;
+ // srem X, C -> we know that the result is within 0..C-1 when C is a
+ // positive constant and the sign bits are at most TypeBits - log2(C).
+ if (match(U->getOperand(1), m_APInt(Denominator))) {
+
+ // Ignore non-positive denominator.
+ if (!Denominator->isStrictlyPositive())
+ break;
+
+ // Calculate the incoming numerator bits. SRem by a positive constant
+ // can't lower the number of sign bits.
+ unsigned NumrBits =
+ ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q);
+
+ // Calculate the leading sign bit constraints by examining the
+ // denominator. The remainder is in the range 0..C-1, which is
+ // calculated by the log2(denominator). The sign bits are the bit-width
+ // minus this value. The result of this subtraction has to be positive.
+ unsigned ResBits = TyBits - Denominator->logBase2();
+
+ return std::max(NumrBits, ResBits);
+ }
+ break;
+ }
case Instruction::AShr: {
- Tmp = ComputeNumSignBits(U->getOperand(0), TD, Depth+1, Q);
+ Tmp = ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q);
// ashr X, C -> adds C sign bits. Vectors too.
const APInt *ShAmt;
if (match(U->getOperand(1), m_APInt(ShAmt))) {
const APInt *ShAmt;
if (match(U->getOperand(1), m_APInt(ShAmt))) {
// shl destroys sign bits.
- Tmp = ComputeNumSignBits(U->getOperand(0), TD, Depth+1, Q);
+ Tmp = ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q);
Tmp2 = ShAmt->getZExtValue();
if (Tmp2 >= TyBits || // Bad shift.
Tmp2 >= Tmp) break; // Shifted all sign bits out.
case Instruction::Or:
case Instruction::Xor: // NOT is handled here.
// Logical binary ops preserve the number of sign bits at the worst.
- Tmp = ComputeNumSignBits(U->getOperand(0), TD, Depth+1, Q);
+ Tmp = ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q);
if (Tmp != 1) {
- Tmp2 = ComputeNumSignBits(U->getOperand(1), TD, Depth+1, Q);
+ Tmp2 = ComputeNumSignBits(U->getOperand(1), DL, Depth + 1, Q);
FirstAnswer = std::min(Tmp, Tmp2);
// We computed what we know about the sign bits as our first
// answer. Now proceed to the generic code that uses
break;
case Instruction::Select:
- Tmp = ComputeNumSignBits(U->getOperand(1), TD, Depth+1, Q);
+ Tmp = ComputeNumSignBits(U->getOperand(1), DL, Depth + 1, Q);
if (Tmp == 1) return 1; // Early out.
- Tmp2 = ComputeNumSignBits(U->getOperand(2), TD, Depth+1, Q);
+ Tmp2 = ComputeNumSignBits(U->getOperand(2), DL, Depth + 1, Q);
return std::min(Tmp, Tmp2);
case Instruction::Add:
// Add can have at most one carry bit. Thus we know that the output
// is, at worst, one more bit than the inputs.
- Tmp = ComputeNumSignBits(U->getOperand(0), TD, Depth+1, Q);
+ Tmp = ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q);
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);
+ computeKnownBits(U->getOperand(0), KnownZero, KnownOne, DL, Depth + 1,
+ Q);
// If the input is known to be 0 or 1, the output is 0/-1, which is all
// sign bits set.
return Tmp;
}
- Tmp2 = ComputeNumSignBits(U->getOperand(1), TD, Depth+1, Q);
+ Tmp2 = ComputeNumSignBits(U->getOperand(1), DL, Depth + 1, Q);
if (Tmp2 == 1) return 1;
return std::min(Tmp, Tmp2)-1;
case Instruction::Sub:
- Tmp2 = ComputeNumSignBits(U->getOperand(1), TD, Depth+1, Q);
+ Tmp2 = ComputeNumSignBits(U->getOperand(1), DL, 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);
+ computeKnownBits(U->getOperand(1), KnownZero, KnownOne, DL, Depth + 1,
+ Q);
// If the input is known to be 0 or 1, the output is 0/-1, which is all
// sign bits set.
if ((KnownZero | APInt(TyBits, 1)).isAllOnesValue())
// Sub can have at most one carry bit. Thus we know that the output
// is, at worst, one more bit than the inputs.
- Tmp = ComputeNumSignBits(U->getOperand(0), TD, Depth+1, Q);
+ Tmp = ComputeNumSignBits(U->getOperand(0), DL, Depth + 1, Q);
if (Tmp == 1) return 1; // Early out.
return std::min(Tmp, Tmp2)-1;
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) {
+ Tmp = ComputeNumSignBits(PN->getIncomingValue(0), DL, Depth + 1, Q);
+ for (unsigned i = 1, e = NumIncomingValues; i != e; ++i) {
if (Tmp == 1) return Tmp;
- Tmp = std::min(Tmp,
- ComputeNumSignBits(PN->getIncomingValue(i), TD,
- Depth+1, Q));
+ Tmp = std::min(
+ Tmp, ComputeNumSignBits(PN->getIncomingValue(i), DL, Depth + 1, Q));
}
return Tmp;
}
// use this information.
APInt KnownZero(TyBits, 0), KnownOne(TyBits, 0);
APInt Mask;
- computeKnownBits(V, KnownZero, KnownOne, TD, Depth, Q);
+ computeKnownBits(V, KnownZero, KnownOne, DL, Depth, Q);
if (KnownZero.isNegative()) { // sign bit is 0
Mask = KnownZero;
return std::max(FirstAnswer, std::min(TyBits, Mask.countLeadingZeros()));
}
-/// ComputeMultiple - This function computes the integer multiple of Base that
-/// equals V. If successful, it returns true and returns the multiple in
-/// Multiple. If unsuccessful, it returns false. It looks
+/// This function computes the integer multiple of Base that equals V.
+/// If successful, it returns true and returns the multiple in
+/// Multiple. If unsuccessful, it returns false. It looks
/// through SExt instructions only if LookThroughSExt is true.
bool llvm::ComputeMultiple(Value *V, unsigned Base, Value *&Multiple,
bool LookThroughSExt, unsigned Depth) {
return false;
}
-/// CannotBeNegativeZero - Return true if we can prove that the specified FP
-/// value is never equal to -0.0.
+/// Return true if we can prove that the specified FP value is never equal to
+/// -0.0.
///
/// NOTE: this function will need to be revisited when we support non-default
/// rounding modes!
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(V))
return !CFP->getValueAPF().isNegZero();
+ // FIXME: Magic number! At the least, this should be given a name because it's
+ // used similarly in CannotBeOrderedLessThanZero(). A better fix may be to
+ // expose it as a parameter, so it can be used for testing / experimenting.
if (Depth == 6)
- return 1; // Limit search depth.
+ return false; // Limit search depth.
const Operator *I = dyn_cast<Operator>(V);
if (!I) return false;
return false;
}
-/// isBytewiseValue - If the specified value can be set by repeating the same
-/// byte in memory, return the i8 value that it is represented with. This is
+bool llvm::CannotBeOrderedLessThanZero(const Value *V, unsigned Depth) {
+ if (const ConstantFP *CFP = dyn_cast<ConstantFP>(V))
+ return !CFP->getValueAPF().isNegative() || CFP->getValueAPF().isZero();
+
+ // FIXME: Magic number! At the least, this should be given a name because it's
+ // used similarly in CannotBeNegativeZero(). A better fix may be to
+ // expose it as a parameter, so it can be used for testing / experimenting.
+ if (Depth == 6)
+ return false; // Limit search depth.
+
+ const Operator *I = dyn_cast<Operator>(V);
+ if (!I) return false;
+
+ switch (I->getOpcode()) {
+ default: break;
+ case Instruction::FMul:
+ // x*x is always non-negative or a NaN.
+ if (I->getOperand(0) == I->getOperand(1))
+ return true;
+ // Fall through
+ case Instruction::FAdd:
+ case Instruction::FDiv:
+ case Instruction::FRem:
+ return CannotBeOrderedLessThanZero(I->getOperand(0), Depth+1) &&
+ CannotBeOrderedLessThanZero(I->getOperand(1), Depth+1);
+ case Instruction::FPExt:
+ case Instruction::FPTrunc:
+ // Widening/narrowing never change sign.
+ return CannotBeOrderedLessThanZero(I->getOperand(0), Depth+1);
+ case Instruction::Call:
+ if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
+ switch (II->getIntrinsicID()) {
+ default: break;
+ case Intrinsic::exp:
+ case Intrinsic::exp2:
+ case Intrinsic::fabs:
+ case Intrinsic::sqrt:
+ return true;
+ case Intrinsic::powi:
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
+ // powi(x,n) is non-negative if n is even.
+ if (CI->getBitWidth() <= 64 && CI->getSExtValue() % 2u == 0)
+ return true;
+ }
+ return CannotBeOrderedLessThanZero(I->getOperand(0), Depth+1);
+ case Intrinsic::fma:
+ case Intrinsic::fmuladd:
+ // x*x+y is non-negative if y is non-negative.
+ return I->getOperand(0) == I->getOperand(1) &&
+ CannotBeOrderedLessThanZero(I->getOperand(2), Depth+1);
+ }
+ break;
+ }
+ return false;
+}
+
+/// If the specified value can be set by repeating the same byte in memory,
+/// return the i8 value that it is represented with. This is
/// true for all i8 values obviously, but is also true for i32 0, i32 -1,
/// i16 0xF0F0, double 0.0 etc. If the value can't be handled with a repeated
/// byte store (e.g. i16 0x1234), return null.
// Don't handle long double formats, which have strange constraints.
}
- // We can handle constant integers that are power of two in size and a
- // multiple of 8 bits.
+ // We can handle constant integers that are multiple of 8 bits.
if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
- unsigned Width = CI->getBitWidth();
- if (isPowerOf2_32(Width) && Width > 8) {
- // We can handle this value if the recursive binary decomposition is the
- // same at all levels.
- APInt Val = CI->getValue();
- APInt Val2;
- while (Val.getBitWidth() != 8) {
- unsigned NextWidth = Val.getBitWidth()/2;
- Val2 = Val.lshr(NextWidth);
- Val2 = Val2.trunc(Val.getBitWidth()/2);
- Val = Val.trunc(Val.getBitWidth()/2);
-
- // If the top/bottom halves aren't the same, reject it.
- if (Val != Val2)
- return nullptr;
- }
- return ConstantInt::get(V->getContext(), Val);
+ if (CI->getBitWidth() % 8 == 0) {
+ assert(CI->getBitWidth() > 8 && "8 bits should be handled above!");
+
+ // We can check that all bytes of an integer are equal by making use of a
+ // little trick: rotate by 8 and check if it's still the same value.
+ if (CI->getValue() != CI->getValue().rotl(8))
+ return nullptr;
+ return ConstantInt::get(V->getContext(), CI->getValue().trunc(8));
}
}
return BuildSubAggregate(From, To, IndexedType, Idxs, IdxSkip, InsertBefore);
}
-/// FindInsertedValue - Given an aggregrate and an sequence of indices, see if
+/// Given an aggregrate and an sequence of indices, see if
/// the scalar value indexed is already around as a register, for example if it
/// were inserted directly into the aggregrate.
///
return nullptr;
}
-/// GetPointerBaseWithConstantOffset - Analyze the specified pointer to see if
-/// it can be expressed as a base pointer plus a constant offset. Return the
-/// base and offset to the caller.
+/// Analyze the specified pointer to see if it can be expressed as a base
+/// pointer plus a constant offset. Return the base and offset to the caller.
Value *llvm::GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
- const DataLayout *DL) {
- // Without DataLayout, conservatively assume 64-bit offsets, which is
- // the widest we support.
- unsigned BitWidth = DL ? DL->getPointerTypeSizeInBits(Ptr->getType()) : 64;
+ const DataLayout &DL) {
+ unsigned BitWidth = DL.getPointerTypeSizeInBits(Ptr->getType());
APInt ByteOffset(BitWidth, 0);
while (1) {
if (Ptr->getType()->isVectorTy())
break;
if (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
- if (DL) {
- APInt GEPOffset(BitWidth, 0);
- if (!GEP->accumulateConstantOffset(*DL, GEPOffset))
- break;
+ APInt GEPOffset(BitWidth, 0);
+ if (!GEP->accumulateConstantOffset(DL, GEPOffset))
+ break;
- ByteOffset += GEPOffset;
- }
+ ByteOffset += GEPOffset;
Ptr = GEP->getPointerOperand();
} else if (Operator::getOpcode(Ptr) == Instruction::BitCast ||
}
-/// getConstantStringInfo - This function computes the length of a
-/// null-terminated C string pointed to by V. If successful, it returns true
-/// and returns the string in Str. If unsuccessful, it returns false.
+/// This function computes the length of a null-terminated C string pointed to
+/// by V. If successful, it returns true and returns the string in Str.
+/// If unsuccessful, it returns false.
bool llvm::getConstantStringInfo(const Value *V, StringRef &Str,
uint64_t Offset, bool TrimAtNul) {
assert(V);
// nodes.
// TODO: See if we can integrate these two together.
-/// GetStringLengthH - If we can compute the length of the string pointed to by
+/// If we can compute the length of the string pointed to by
/// the specified pointer, return 'len+1'. If we can't, return 0.
static uint64_t GetStringLengthH(Value *V, SmallPtrSetImpl<PHINode*> &PHIs) {
// Look through noop bitcast instructions.
// 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.
return StrData.size()+1;
}
-/// GetStringLength - If we can compute the length of the string pointed to by
+/// If we can compute the length of the string pointed to by
/// the specified pointer, return 'len+1'. If we can't, return 0.
uint64_t llvm::GetStringLength(Value *V) {
if (!V->getType()->isPointerTy()) return 0;
return Len == ~0ULL ? 1 : Len;
}
-Value *
-llvm::GetUnderlyingObject(Value *V, const DataLayout *TD, unsigned MaxLookup) {
+Value *llvm::GetUnderlyingObject(Value *V, const DataLayout &DL,
+ unsigned MaxLookup) {
if (!V->getType()->isPointerTy())
return V;
for (unsigned Count = 0; MaxLookup == 0 || Count < MaxLookup; ++Count) {
} else {
// See if InstructionSimplify knows any relevant tricks.
if (Instruction *I = dyn_cast<Instruction>(V))
- // TODO: Acquire a DominatorTree and AssumptionTracker and use them.
- if (Value *Simplified = SimplifyInstruction(I, TD, nullptr)) {
+ // TODO: Acquire a DominatorTree and AssumptionCache and use them.
+ if (Value *Simplified = SimplifyInstruction(I, DL, nullptr)) {
V = Simplified;
continue;
}
return V;
}
-void
-llvm::GetUnderlyingObjects(Value *V,
- SmallVectorImpl<Value *> &Objects,
- const DataLayout *TD,
- unsigned MaxLookup) {
+void llvm::GetUnderlyingObjects(Value *V, SmallVectorImpl<Value *> &Objects,
+ const DataLayout &DL, unsigned MaxLookup) {
SmallPtrSet<Value *, 4> Visited;
SmallVector<Value *, 4> Worklist;
Worklist.push_back(V);
do {
Value *P = Worklist.pop_back_val();
- P = GetUnderlyingObject(P, TD, MaxLookup);
+ P = GetUnderlyingObject(P, DL, MaxLookup);
- if (!Visited.insert(P))
+ if (!Visited.insert(P).second)
continue;
if (SelectInst *SI = dyn_cast<SelectInst>(P)) {
} while (!Worklist.empty());
}
-/// onlyUsedByLifetimeMarkers - Return true if the only users of this pointer
-/// are lifetime markers.
-///
+/// Return true if the only users of this pointer are lifetime markers.
bool llvm::onlyUsedByLifetimeMarkers(const Value *V) {
for (const User *U : V->users()) {
const IntrinsicInst *II = dyn_cast<IntrinsicInst>(U);
return true;
}
-bool llvm::isSafeToSpeculativelyExecute(const Value *V,
- const DataLayout *TD) {
+bool llvm::isSafeToSpeculativelyExecute(const Value *V) {
const Operator *Inst = dyn_cast<Operator>(V);
if (!Inst)
return false;
default:
return true;
case Instruction::UDiv:
- case Instruction::URem:
- // x / y is undefined if y == 0, but calculations like x / 3 are safe.
- return isKnownNonZero(Inst->getOperand(1), TD);
+ case Instruction::URem: {
+ // x / y is undefined if y == 0.
+ const APInt *V;
+ if (match(Inst->getOperand(1), m_APInt(V)))
+ return *V != 0;
+ return false;
+ }
case Instruction::SDiv:
case Instruction::SRem: {
- Value *Op = Inst->getOperand(1);
- // x / y is undefined if y == 0
- if (!isKnownNonZero(Op, TD))
+ // x / y is undefined if y == 0 or x == INT_MIN and y == -1
+ const APInt *Numerator, *Denominator;
+ if (!match(Inst->getOperand(1), m_APInt(Denominator)))
return false;
- // x / y might be undefined if y == -1
- unsigned BitWidth = getBitWidth(Op->getType(), TD);
- if (BitWidth == 0)
+ // We cannot hoist this division if the denominator is 0.
+ if (*Denominator == 0)
return false;
- APInt KnownZero(BitWidth, 0);
- APInt KnownOne(BitWidth, 0);
- computeKnownBits(Op, KnownZero, KnownOne, TD);
- return !!KnownZero;
+ // It's safe to hoist if the denominator is not 0 or -1.
+ if (*Denominator != -1)
+ return true;
+ // At this point we know that the denominator is -1. It is safe to hoist as
+ // long we know that the numerator is not INT_MIN.
+ if (match(Inst->getOperand(0), m_APInt(Numerator)))
+ return !Numerator->isMinSignedValue();
+ // The numerator *might* be MinSignedValue.
+ return false;
}
case Instruction::Load: {
const LoadInst *LI = cast<LoadInst>(Inst);
// Speculative load may create a race that did not exist in the source.
LI->getParent()->getParent()->hasFnAttribute(Attribute::SanitizeThread))
return false;
- return LI->getPointerOperand()->isDereferenceablePointer(TD);
+ const DataLayout &DL = LI->getModule()->getDataLayout();
+ return LI->getPointerOperand()->isDereferenceablePointer(DL);
}
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:
- 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.
}
}
}
-/// isKnownNonNull - Return true if we know that the specified value is never
-/// null.
+/// Return true if we know that the specified value is never null.
bool llvm::isKnownNonNull(const Value *V, const TargetLibraryInfo *TLI) {
// Alloca never returns null, malloc might.
if (isa<AllocaInst>(V)) return true;
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
return !GV->hasExternalWeakLinkage();
+ // A Load tagged w/nonnull metadata is never null.
+ if (const LoadInst *LI = dyn_cast<LoadInst>(V))
+ return LI->getMetadata(LLVMContext::MD_nonnull);
+
if (ImmutableCallSite CS = V)
if (CS.isReturnNonNull())
return true;
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;
+}
+
+OverflowResult llvm::computeOverflowForUnsignedAdd(Value *LHS, Value *RHS,
+ const DataLayout &DL,
+ AssumptionCache *AC,
+ const Instruction *CxtI,
+ const DominatorTree *DT) {
+ bool LHSKnownNonNegative, LHSKnownNegative;
+ ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, DL, /*Depth=*/0,
+ AC, CxtI, DT);
+ if (LHSKnownNonNegative || LHSKnownNegative) {
+ bool RHSKnownNonNegative, RHSKnownNegative;
+ ComputeSignBit(RHS, RHSKnownNonNegative, RHSKnownNegative, DL, /*Depth=*/0,
+ AC, CxtI, DT);
+
+ if (LHSKnownNegative && RHSKnownNegative) {
+ // The sign bit is set in both cases: this MUST overflow.
+ // Create a simple add instruction, and insert it into the struct.
+ return OverflowResult::AlwaysOverflows;
+ }
+
+ if (LHSKnownNonNegative && RHSKnownNonNegative) {
+ // The sign bit is clear in both cases: this CANNOT overflow.
+ // Create a simple add instruction, and insert it into the struct.
+ return OverflowResult::NeverOverflows;
+ }
+ }
+
+ return OverflowResult::MayOverflow;
+}
projects / oota-llvm.git / blobdiff