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.
+/// 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) {
if (unsigned BitWidth = Ty->getScalarSizeInBits())
return BitWidth;
};
} // 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
switch (I->getOpcode()) {
default: break;
case Instruction::Load:
- if (MDNode *MD = cast<LoadInst>(I)->getMetadata(LLVMContext::MD_range))
+ if (MDNode *MD = cast<LoadInst>(I)->getMDNode(LLVMContext::MD_range))
computeKnownBitsFromRangeMetadata(*MD, KnownZero);
break;
case Instruction::And: {
}
case Instruction::Call:
case Instruction::Invoke:
- if (MDNode *MD = cast<Instruction>(I)->getMetadata(LLVMContext::MD_range))
+ if (MDNode *MD = cast<Instruction>(I)->getMDNode(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
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) {
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) {
return true;
}
-/// 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.
+/// 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,
const Query &Q) {
if (Constant *C = dyn_cast<Constant>(V)) {
}
if (Instruction* I = dyn_cast<Instruction>(V)) {
- if (MDNode *Ranges = I->getMetadata(LLVMContext::MD_range)) {
+ if (MDNode *Ranges = I->getMDNode(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())) {
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
-/// 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.
///
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!
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
+/// 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.
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
}
-/// 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.
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;
} 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);
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))
- return false;
- // x / y might be undefined if y == -1
- unsigned BitWidth = getBitWidth(Op->getType(), TD);
- if (BitWidth == 0)
- return false;
- APInt KnownZero(BitWidth, 0);
- APInt KnownOne(BitWidth, 0);
- computeKnownBits(Op, KnownZero, KnownOne, TD);
- return !!KnownZero;
+ // x / y is undefined if y == 0 or x == INT_MIN and y == -1
+ const APInt *X, *Y;
+ if (match(Inst->getOperand(1), m_APInt(Y))) {
+ if (*Y != 0) {
+ if (*Y == -1) {
+ // The numerator can't be MinSignedValue if the denominator is -1.
+ if (match(Inst->getOperand(0), m_APInt(X)))
+ return !Y->isMinSignedValue();
+ // The numerator *might* be MinSignedValue.
+ return false;
+ }
+ // The denominator is not 0 or -1, it's safe to proceed.
+ return true;
+ }
+ }
+ return false;
}
case Instruction::Load: {
const LoadInst *LI = cast<LoadInst>(Inst);
}
}
-/// 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;
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