constexpr unsigned MaxAnalysisRecursionDepth = 6;
- /// Determine which bits of V are known to be either zero or one and return
- /// them in the KnownZero/KnownOne bit sets.
- ///
- /// This function is defined on values with integer type, values with pointer
- /// type, and vectors of integers. In the case
- /// where V is a vector, the 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(const Value *V, KnownBits &Known,
- const DataLayout &DL, unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- OptimizationRemarkEmitter *ORE = nullptr,
- bool UseInstrInfo = true);
-
- /// Determine which bits of V are known to be either zero or one and return
- /// them in the KnownZero/KnownOne bit sets.
- ///
- /// This function is defined on values with integer type, values with pointer
- /// type, and vectors of integers. In the case
- /// where V is a vector, the 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 demanded elements in the vector.
- void computeKnownBits(const Value *V, const APInt &DemandedElts,
- KnownBits &Known, const DataLayout &DL,
- unsigned Depth = 0, AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- OptimizationRemarkEmitter *ORE = nullptr,
- bool UseInstrInfo = true);
-
- /// Returns the known bits rather than passing by reference.
- KnownBits computeKnownBits(const Value *V, const DataLayout &DL,
- unsigned Depth = 0, AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- OptimizationRemarkEmitter *ORE = nullptr,
- bool UseInstrInfo = true);
-
- /// Returns the known bits rather than passing by reference.
- KnownBits computeKnownBits(const Value *V, const APInt &DemandedElts,
- const DataLayout &DL, unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- OptimizationRemarkEmitter *ORE = nullptr,
- bool UseInstrInfo = true);
-
- /// Compute known bits from the range metadata.
- /// \p KnownZero the set of bits that are known to be zero
- /// \p KnownOne the set of bits that are known to be one
- void computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
- KnownBits &Known);
-
- /// Return true if LHS and RHS have no common bits set.
- bool haveNoCommonBitsSet(const Value *LHS, const Value *RHS,
- const DataLayout &DL,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- bool UseInstrInfo = true);
+/// Determine which bits of V are known to be either zero or one and return
+/// them in the KnownZero/KnownOne bit sets.
+///
+/// This function is defined on values with integer type, values with pointer
+/// type, and vectors of integers. In the case
+/// where V is a vector, the 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(const Value *V, KnownBits &Known, const DataLayout &DL,
+ unsigned Depth = 0, AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ OptimizationRemarkEmitter *ORE = nullptr,
+ bool UseInstrInfo = true);
- /// 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 type and
- /// vectors of integers. If 'OrZero' is set, then return true if the given
- /// value is either a power of two or zero.
- bool isKnownToBeAPowerOfTwo(const Value *V, const DataLayout &DL,
- bool OrZero = false, unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- bool UseInstrInfo = true);
-
- bool isOnlyUsedInZeroEqualityComparison(const Instruction *CxtI);
-
- /// 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. For pointers, if the context instruction and dominator tree are
- /// specified, perform context-sensitive analysis and return true if the
- /// pointer couldn't possibly be null at the specified instruction.
- /// Supports values with integer or pointer type and vectors of integers.
- bool isKnownNonZero(const Value *V, const DataLayout &DL, unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
+/// Determine which bits of V are known to be either zero or one and return
+/// them in the KnownZero/KnownOne bit sets.
+///
+/// This function is defined on values with integer type, values with pointer
+/// type, and vectors of integers. In the case
+/// where V is a vector, the 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 demanded elements in the vector.
+void computeKnownBits(const Value *V, const APInt &DemandedElts,
+ KnownBits &Known, const DataLayout &DL,
+ unsigned Depth = 0, AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr,
const DominatorTree *DT = nullptr,
+ OptimizationRemarkEmitter *ORE = nullptr,
bool UseInstrInfo = true);
- /// Return true if the two given values are negation.
- /// Currently can recoginze Value pair:
- /// 1: <X, Y> if X = sub (0, Y) or Y = sub (0, X)
- /// 2: <X, Y> if X = sub (A, B) and Y = sub (B, A)
- bool isKnownNegation(const Value *X, const Value *Y, bool NeedNSW = false);
-
- /// Returns true if the give value is known to be non-negative.
- bool isKnownNonNegative(const Value *V, const DataLayout &DL,
- unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- bool UseInstrInfo = true);
-
- /// Returns true if the given value is known be positive (i.e. non-negative
- /// and non-zero).
- bool isKnownPositive(const Value *V, const DataLayout &DL, unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- bool UseInstrInfo = true);
+/// Returns the known bits rather than passing by reference.
+KnownBits computeKnownBits(const Value *V, const DataLayout &DL,
+ unsigned Depth = 0, AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ OptimizationRemarkEmitter *ORE = nullptr,
+ bool UseInstrInfo = true);
- /// Returns true if the given value is known be negative (i.e. non-positive
- /// and non-zero).
- bool isKnownNegative(const Value *V, const DataLayout &DL, unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- bool UseInstrInfo = true);
+/// Returns the known bits rather than passing by reference.
+KnownBits computeKnownBits(const Value *V, const APInt &DemandedElts,
+ const DataLayout &DL, unsigned Depth = 0,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ OptimizationRemarkEmitter *ORE = nullptr,
+ bool UseInstrInfo = true);
- /// Return true if the given values are known to be non-equal when defined.
- /// Supports scalar integer types only.
- bool isKnownNonEqual(const Value *V1, const Value *V2, const DataLayout &DL,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- bool UseInstrInfo = true);
+/// Compute known bits from the range metadata.
+/// \p KnownZero the set of bits that are known to be zero
+/// \p KnownOne the set of bits that are known to be one
+void computeKnownBitsFromRangeMetadata(const MDNode &Ranges, KnownBits &Known);
- /// 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, 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(const Value *V, const APInt &Mask,
- const DataLayout &DL,
- unsigned Depth = 0, AssumptionCache *AC = nullptr,
+/// Return true if LHS and RHS have no common bits set.
+bool haveNoCommonBitsSet(const Value *LHS, const Value *RHS,
+ const DataLayout &DL, AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr,
const DominatorTree *DT = nullptr,
bool UseInstrInfo = true);
- /// 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. For vectors, return the number of
- /// sign bits for the vector element with the mininum number of known sign
- /// bits.
- unsigned ComputeNumSignBits(const Value *Op, const DataLayout &DL,
- unsigned Depth = 0, AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr,
- bool UseInstrInfo = true);
-
- /// Get the upper bound on bit size for this Value \p Op as a signed integer.
- /// i.e. x == sext(trunc(x to MaxSignificantBits) to bitwidth(x)).
- /// Similar to the APInt::getSignificantBits function.
- unsigned ComputeMaxSignificantBits(const Value *Op, const DataLayout &DL,
- unsigned Depth = 0,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr);
-
- /// Map a call instruction to an intrinsic ID. Libcalls which have equivalent
- /// intrinsics are treated as-if they were intrinsics.
- Intrinsic::ID getIntrinsicForCallSite(const CallBase &CB,
- const TargetLibraryInfo *TLI);
-
- /// Return true if we can prove that the specified FP value is never equal to
- /// -0.0.
- bool CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI,
- unsigned Depth = 0);
-
- /// Return true if we can prove that the specified FP value is either NaN or
- /// never less than -0.0.
- ///
- /// NaN --> true
- /// +0 --> true
- /// -0 --> true
- /// x > +0 --> true
- /// x < -0 --> false
- bool CannotBeOrderedLessThanZero(const Value *V, const TargetLibraryInfo *TLI);
-
- /// Return true if the floating-point scalar value is not an infinity or if
- /// the floating-point vector value has no infinities. Return false if a value
- /// could ever be infinity.
- bool isKnownNeverInfinity(const Value *V, const TargetLibraryInfo *TLI,
- unsigned Depth = 0);
-
- /// Return true if the floating-point scalar value is not a NaN or if the
- /// floating-point vector value has no NaN elements. Return false if a value
- /// could ever be NaN.
- bool isKnownNeverNaN(const Value *V, const TargetLibraryInfo *TLI,
- unsigned Depth = 0);
-
- /// Return true if we can prove that the specified FP value's sign bit is 0.
- ///
- /// NaN --> true/false (depending on the NaN's sign bit)
- /// +0 --> true
- /// -0 --> false
- /// x > +0 --> true
- /// x < -0 --> false
- bool SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI);
-
- /// 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. If the value is entirely undef and padding,
- /// return undef.
- Value *isBytewiseValue(Value *V, const DataLayout &DL);
-
- /// Given an aggregate 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 aggregate.
- ///
- /// If InsertBefore is not null, this function will duplicate (modified)
- /// insertvalues when a part of a nested struct is extracted.
- Value *FindInsertedValue(Value *V,
- ArrayRef<unsigned> idx_range,
- Instruction *InsertBefore = nullptr);
-
- /// 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.
- ///
- /// This is a wrapper around Value::stripAndAccumulateConstantOffsets that
- /// creates and later unpacks the required APInt.
- inline Value *GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
- const DataLayout &DL,
- bool AllowNonInbounds = true) {
- APInt OffsetAPInt(DL.getIndexTypeSizeInBits(Ptr->getType()), 0);
- Value *Base =
- Ptr->stripAndAccumulateConstantOffsets(DL, OffsetAPInt, AllowNonInbounds);
-
- Offset = OffsetAPInt.getSExtValue();
- return Base;
- }
- inline const Value *
- GetPointerBaseWithConstantOffset(const Value *Ptr, int64_t &Offset,
- const DataLayout &DL,
- bool AllowNonInbounds = true) {
- return GetPointerBaseWithConstantOffset(const_cast<Value *>(Ptr), Offset, DL,
- AllowNonInbounds);
- }
+/// 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 type and
+/// vectors of integers. If 'OrZero' is set, then return true if the given
+/// value is either a power of two or zero.
+bool isKnownToBeAPowerOfTwo(const Value *V, const DataLayout &DL,
+ bool OrZero = false, unsigned Depth = 0,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
+
+bool isOnlyUsedInZeroEqualityComparison(const Instruction *CxtI);
+
+/// 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. For pointers, if the context instruction and dominator tree are
+/// specified, perform context-sensitive analysis and return true if the
+/// pointer couldn't possibly be null at the specified instruction.
+/// Supports values with integer or pointer type and vectors of integers.
+bool isKnownNonZero(const Value *V, const DataLayout &DL, unsigned Depth = 0,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
+
+/// Return true if the two given values are negation.
+/// Currently can recoginze Value pair:
+/// 1: <X, Y> if X = sub (0, Y) or Y = sub (0, X)
+/// 2: <X, Y> if X = sub (A, B) and Y = sub (B, A)
+bool isKnownNegation(const Value *X, const Value *Y, bool NeedNSW = false);
+
+/// Returns true if the give value is known to be non-negative.
+bool isKnownNonNegative(const Value *V, const DataLayout &DL,
+ unsigned Depth = 0, AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
- /// Returns true if the GEP is based on a pointer to a string (array of
- // \p CharSize integers) and is indexing into this string.
- bool isGEPBasedOnPointerToString(const GEPOperator *GEP,
- unsigned CharSize = 8);
-
- /// Represents offset+length into a ConstantDataArray.
- struct ConstantDataArraySlice {
- /// ConstantDataArray pointer. nullptr indicates a zeroinitializer (a valid
- /// initializer, it just doesn't fit the ConstantDataArray interface).
- const ConstantDataArray *Array;
-
- /// Slice starts at this Offset.
- uint64_t Offset;
-
- /// Length of the slice.
- uint64_t Length;
-
- /// Moves the Offset and adjusts Length accordingly.
- void move(uint64_t Delta) {
- assert(Delta < Length);
- Offset += Delta;
- Length -= Delta;
- }
-
- /// Convenience accessor for elements in the slice.
- uint64_t operator[](unsigned I) const {
- return Array==nullptr ? 0 : Array->getElementAsInteger(I + Offset);
- }
- };
-
- /// Returns true if the value \p V is a pointer into a ConstantDataArray.
- /// If successful \p Slice will point to a ConstantDataArray info object
- /// with an appropriate offset.
- bool getConstantDataArrayInfo(const Value *V, ConstantDataArraySlice &Slice,
- unsigned ElementSize, uint64_t Offset = 0);
-
- /// 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 does not include the trailing null
- /// character by default. If TrimAtNul is set to false, then this returns any
- /// trailing null characters as well as any other characters that come after
- /// it.
- bool getConstantStringInfo(const Value *V, StringRef &Str,
- uint64_t Offset = 0, bool TrimAtNul = true);
-
- /// 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 GetStringLength(const Value *V, unsigned CharSize = 8);
-
- /// This function returns call pointer argument that is considered the same by
- /// aliasing rules. You CAN'T use it to replace one value with another. If
- /// \p MustPreserveNullness is true, the call must preserve the nullness of
- /// the pointer.
- const Value *getArgumentAliasingToReturnedPointer(const CallBase *Call,
- bool MustPreserveNullness);
- inline Value *
- getArgumentAliasingToReturnedPointer(CallBase *Call,
- bool MustPreserveNullness) {
- return const_cast<Value *>(getArgumentAliasingToReturnedPointer(
- const_cast<const CallBase *>(Call), MustPreserveNullness));
- }
+/// Returns true if the given value is known be positive (i.e. non-negative
+/// and non-zero).
+bool isKnownPositive(const Value *V, const DataLayout &DL, unsigned Depth = 0,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
+
+/// Returns true if the given value is known be negative (i.e. non-positive
+/// and non-zero).
+bool isKnownNegative(const Value *V, const DataLayout &DL, unsigned Depth = 0,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
+
+/// Return true if the given values are known to be non-equal when defined.
+/// Supports scalar integer types only.
+bool isKnownNonEqual(const Value *V1, const Value *V2, const DataLayout &DL,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
+
+/// 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, 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(const Value *V, const APInt &Mask, const DataLayout &DL,
+ unsigned Depth = 0, AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
- /// {launder,strip}.invariant.group returns pointer that aliases its argument,
- /// and it only captures pointer by returning it.
- /// These intrinsics are not marked as nocapture, because returning is
- /// considered as capture. The arguments are not marked as returned neither,
- /// because it would make it useless. If \p MustPreserveNullness is true,
- /// the intrinsic must preserve the nullness of the pointer.
- bool isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
- const CallBase *Call, bool MustPreserveNullness);
-
- /// This method strips off any GEP address adjustments and pointer casts from
- /// the specified value, returning the original object being addressed. Note
- /// that the returned value has pointer type if the specified value does. If
- /// the MaxLookup value is non-zero, it limits the number of instructions to
- /// be stripped off.
- const Value *getUnderlyingObject(const Value *V, unsigned MaxLookup = 6);
- inline Value *getUnderlyingObject(Value *V, unsigned MaxLookup = 6) {
- // Force const to avoid infinite recursion.
- const Value *VConst = V;
- return const_cast<Value *>(getUnderlyingObject(VConst, MaxLookup));
+/// 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. For vectors, return the number of
+/// sign bits for the vector element with the mininum number of known sign
+/// bits.
+unsigned ComputeNumSignBits(const Value *Op, const DataLayout &DL,
+ unsigned Depth = 0, AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr,
+ bool UseInstrInfo = true);
+
+/// Get the upper bound on bit size for this Value \p Op as a signed integer.
+/// i.e. x == sext(trunc(x to MaxSignificantBits) to bitwidth(x)).
+/// Similar to the APInt::getSignificantBits function.
+unsigned ComputeMaxSignificantBits(const Value *Op, const DataLayout &DL,
+ unsigned Depth = 0,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr);
+
+/// Map a call instruction to an intrinsic ID. Libcalls which have equivalent
+/// intrinsics are treated as-if they were intrinsics.
+Intrinsic::ID getIntrinsicForCallSite(const CallBase &CB,
+ const TargetLibraryInfo *TLI);
+
+/// Return true if we can prove that the specified FP value is never equal to
+/// -0.0.
+bool CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI,
+ unsigned Depth = 0);
+
+/// Return true if we can prove that the specified FP value is either NaN or
+/// never less than -0.0.
+///
+/// NaN --> true
+/// +0 --> true
+/// -0 --> true
+/// x > +0 --> true
+/// x < -0 --> false
+bool CannotBeOrderedLessThanZero(const Value *V, const TargetLibraryInfo *TLI);
+
+/// Return true if the floating-point scalar value is not an infinity or if
+/// the floating-point vector value has no infinities. Return false if a value
+/// could ever be infinity.
+bool isKnownNeverInfinity(const Value *V, const TargetLibraryInfo *TLI,
+ unsigned Depth = 0);
+
+/// Return true if the floating-point scalar value is not a NaN or if the
+/// floating-point vector value has no NaN elements. Return false if a value
+/// could ever be NaN.
+bool isKnownNeverNaN(const Value *V, const TargetLibraryInfo *TLI,
+ unsigned Depth = 0);
+
+/// Return true if we can prove that the specified FP value's sign bit is 0.
+///
+/// NaN --> true/false (depending on the NaN's sign bit)
+/// +0 --> true
+/// -0 --> false
+/// x > +0 --> true
+/// x < -0 --> false
+bool SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI);
+
+/// 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. If the value is entirely undef and padding,
+/// return undef.
+Value *isBytewiseValue(Value *V, const DataLayout &DL);
+
+/// Given an aggregate 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 aggregate.
+///
+/// If InsertBefore is not null, this function will duplicate (modified)
+/// insertvalues when a part of a nested struct is extracted.
+Value *FindInsertedValue(Value *V, ArrayRef<unsigned> idx_range,
+ Instruction *InsertBefore = nullptr);
+
+/// 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.
+///
+/// This is a wrapper around Value::stripAndAccumulateConstantOffsets that
+/// creates and later unpacks the required APInt.
+inline Value *GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
+ const DataLayout &DL,
+ bool AllowNonInbounds = true) {
+ APInt OffsetAPInt(DL.getIndexTypeSizeInBits(Ptr->getType()), 0);
+ Value *Base =
+ Ptr->stripAndAccumulateConstantOffsets(DL, OffsetAPInt, AllowNonInbounds);
+
+ Offset = OffsetAPInt.getSExtValue();
+ return Base;
+}
+inline const Value *
+GetPointerBaseWithConstantOffset(const Value *Ptr, int64_t &Offset,
+ const DataLayout &DL,
+ bool AllowNonInbounds = true) {
+ return GetPointerBaseWithConstantOffset(const_cast<Value *>(Ptr), Offset, DL,
+ AllowNonInbounds);
+}
+
+/// Returns true if the GEP is based on a pointer to a string (array of
+// \p CharSize integers) and is indexing into this string.
+bool isGEPBasedOnPointerToString(const GEPOperator *GEP, unsigned CharSize = 8);
+
+/// Represents offset+length into a ConstantDataArray.
+struct ConstantDataArraySlice {
+ /// ConstantDataArray pointer. nullptr indicates a zeroinitializer (a valid
+ /// initializer, it just doesn't fit the ConstantDataArray interface).
+ const ConstantDataArray *Array;
+
+ /// Slice starts at this Offset.
+ uint64_t Offset;
+
+ /// Length of the slice.
+ uint64_t Length;
+
+ /// Moves the Offset and adjusts Length accordingly.
+ void move(uint64_t Delta) {
+ assert(Delta < Length);
+ Offset += Delta;
+ Length -= Delta;
}
- /// This method is similar to getUnderlyingObject except that it can
- /// look through phi and select instructions and return multiple objects.
- ///
- /// If LoopInfo is passed, loop phis are further analyzed. If a pointer
- /// accesses different objects in each iteration, we don't look through the
- /// phi node. E.g. consider this loop nest:
- ///
- /// int **A;
- /// for (i)
- /// for (j) {
- /// A[i][j] = A[i-1][j] * B[j]
- /// }
- ///
- /// This is transformed by Load-PRE to stash away A[i] for the next iteration
- /// of the outer loop:
- ///
- /// Curr = A[0]; // Prev_0
- /// for (i: 1..N) {
- /// Prev = Curr; // Prev = PHI (Prev_0, Curr)
- /// Curr = A[i];
- /// for (j: 0..N) {
- /// Curr[j] = Prev[j] * B[j]
- /// }
- /// }
- ///
- /// Since A[i] and A[i-1] are independent pointers, getUnderlyingObjects
- /// should not assume that Curr and Prev share the same underlying object thus
- /// it shouldn't look through the phi above.
- void getUnderlyingObjects(const Value *V,
- SmallVectorImpl<const Value *> &Objects,
- LoopInfo *LI = nullptr, unsigned MaxLookup = 6);
-
- /// This is a wrapper around getUnderlyingObjects and adds support for basic
- /// ptrtoint+arithmetic+inttoptr sequences.
- bool getUnderlyingObjectsForCodeGen(const Value *V,
- SmallVectorImpl<Value *> &Objects);
-
- /// Returns unique alloca where the value comes from, or nullptr.
- /// If OffsetZero is true check that V points to the begining of the alloca.
- AllocaInst *findAllocaForValue(Value *V, bool OffsetZero = false);
- inline const AllocaInst *findAllocaForValue(const Value *V,
- bool OffsetZero = false) {
- return findAllocaForValue(const_cast<Value *>(V), OffsetZero);
+ /// Convenience accessor for elements in the slice.
+ uint64_t operator[](unsigned I) const {
+ return Array == nullptr ? 0 : Array->getElementAsInteger(I + Offset);
}
-
- /// Return true if the only users of this pointer are lifetime markers.
- bool onlyUsedByLifetimeMarkers(const Value *V);
-
- /// Return true if the only users of this pointer are lifetime markers or
- /// droppable instructions.
- bool onlyUsedByLifetimeMarkersOrDroppableInsts(const Value *V);
-
- /// Return true if speculation of the given load must be suppressed to avoid
- /// ordering or interfering with an active sanitizer. If not suppressed,
- /// dereferenceability and alignment must be proven separately. Note: This
- /// is only needed for raw reasoning; if you use the interface below
- /// (isSafeToSpeculativelyExecute), this is handled internally.
- bool mustSuppressSpeculation(const LoadInst &LI);
-
- /// Return true if the instruction does not have any effects besides
- /// calculating the result and does not have undefined behavior.
- ///
- /// This method never returns true for an instruction that returns true for
- /// mayHaveSideEffects; however, this method also does some other checks in
- /// addition. It checks for undefined behavior, like dividing by zero or
- /// loading from an invalid pointer (but not for undefined results, like a
- /// shift with a shift amount larger than the width of the result). It checks
- /// for malloc and alloca because speculatively executing them might cause a
- /// memory leak. It also returns false for instructions related to control
- /// flow, specifically terminators and PHI nodes.
- ///
- /// If the CtxI is specified this method performs context-sensitive analysis
- /// and returns true if it is safe to execute the instruction immediately
- /// before the CtxI.
- ///
- /// If the CtxI is NOT specified this method only looks at the instruction
- /// itself and its operands, so if this method returns true, it is safe to
- /// move the instruction as long as the correct dominance relationships for
- /// the operands and users hold.
- ///
- /// This method can return true for instructions that read memory;
- /// for such instructions, moving them may change the resulting value.
- bool isSafeToSpeculativelyExecute(const Instruction *I,
- const Instruction *CtxI = nullptr,
- const DominatorTree *DT = nullptr,
- const TargetLibraryInfo *TLI = nullptr);
-
- /// This returns the same result as isSafeToSpeculativelyExecute if Opcode is
- /// the actual opcode of Inst. If the provided and actual opcode differ, the
- /// function (virtually) overrides the opcode of Inst with the provided
- /// Opcode. There are come constraints in this case:
- /// * If Opcode has a fixed number of operands (eg, as binary operators do),
- /// then Inst has to have at least as many leading operands. The function
- /// will ignore all trailing operands beyond that number.
- /// * If Opcode allows for an arbitrary number of operands (eg, as CallInsts
- /// do), then all operands are considered.
- /// * The virtual instruction has to satisfy all typing rules of the provided
- /// Opcode.
- /// * This function is pessimistic in the following sense: If one actually
- /// materialized the virtual instruction, then isSafeToSpeculativelyExecute
- /// may say that the materialized instruction is speculatable whereas this
- /// function may have said that the instruction wouldn't be speculatable.
- /// This behavior is a shortcoming in the current implementation and not
- /// intentional.
- bool isSafeToSpeculativelyExecuteWithOpcode(
- unsigned Opcode, const Instruction *Inst,
- const Instruction *CtxI = nullptr, const DominatorTree *DT = nullptr,
- const TargetLibraryInfo *TLI = nullptr);
-
- /// Returns true if the result or effects of the given instructions \p I
- /// depend values not reachable through the def use graph.
- /// * Memory dependence arises for example if the instruction reads from
- /// memory or may produce effects or undefined behaviour. Memory dependent
- /// instructions generally cannot be reorderd with respect to other memory
- /// dependent instructions.
- /// * Control dependence arises for example if the instruction may fault
- /// if lifted above a throwing call or infinite loop.
- bool mayHaveNonDefUseDependency(const Instruction &I);
-
- /// Return true if it is an intrinsic that cannot be speculated but also
- /// cannot trap.
- bool isAssumeLikeIntrinsic(const Instruction *I);
-
- /// Return true if it is valid to use the assumptions provided by an
- /// assume intrinsic, I, at the point in the control-flow identified by the
- /// context instruction, CxtI.
- bool isValidAssumeForContext(const Instruction *I, const Instruction *CxtI,
- const DominatorTree *DT = nullptr);
-
- enum class OverflowResult {
- /// Always overflows in the direction of signed/unsigned min value.
- AlwaysOverflowsLow,
- /// Always overflows in the direction of signed/unsigned max value.
- AlwaysOverflowsHigh,
- /// May or may not overflow.
- MayOverflow,
- /// Never overflows.
- NeverOverflows,
- };
-
- OverflowResult computeOverflowForUnsignedMul(const Value *LHS,
- const Value *RHS,
- const DataLayout &DL,
- AssumptionCache *AC,
- const Instruction *CxtI,
- const DominatorTree *DT,
- bool UseInstrInfo = true);
- OverflowResult computeOverflowForSignedMul(const Value *LHS, const Value *RHS,
+};
+
+/// Returns true if the value \p V is a pointer into a ConstantDataArray.
+/// If successful \p Slice will point to a ConstantDataArray info object
+/// with an appropriate offset.
+bool getConstantDataArrayInfo(const Value *V, ConstantDataArraySlice &Slice,
+ unsigned ElementSize, uint64_t Offset = 0);
+
+/// 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 does not include the trailing null
+/// character by default. If TrimAtNul is set to false, then this returns any
+/// trailing null characters as well as any other characters that come after
+/// it.
+bool getConstantStringInfo(const Value *V, StringRef &Str, uint64_t Offset = 0,
+ bool TrimAtNul = true);
+
+/// 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 GetStringLength(const Value *V, unsigned CharSize = 8);
+
+/// This function returns call pointer argument that is considered the same by
+/// aliasing rules. You CAN'T use it to replace one value with another. If
+/// \p MustPreserveNullness is true, the call must preserve the nullness of
+/// the pointer.
+const Value *getArgumentAliasingToReturnedPointer(const CallBase *Call,
+ bool MustPreserveNullness);
+inline Value *getArgumentAliasingToReturnedPointer(CallBase *Call,
+ bool MustPreserveNullness) {
+ return const_cast<Value *>(getArgumentAliasingToReturnedPointer(
+ const_cast<const CallBase *>(Call), MustPreserveNullness));
+}
+
+/// {launder,strip}.invariant.group returns pointer that aliases its argument,
+/// and it only captures pointer by returning it.
+/// These intrinsics are not marked as nocapture, because returning is
+/// considered as capture. The arguments are not marked as returned neither,
+/// because it would make it useless. If \p MustPreserveNullness is true,
+/// the intrinsic must preserve the nullness of the pointer.
+bool isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
+ const CallBase *Call, bool MustPreserveNullness);
+
+/// This method strips off any GEP address adjustments and pointer casts from
+/// the specified value, returning the original object being addressed. Note
+/// that the returned value has pointer type if the specified value does. If
+/// the MaxLookup value is non-zero, it limits the number of instructions to
+/// be stripped off.
+const Value *getUnderlyingObject(const Value *V, unsigned MaxLookup = 6);
+inline Value *getUnderlyingObject(Value *V, unsigned MaxLookup = 6) {
+ // Force const to avoid infinite recursion.
+ const Value *VConst = V;
+ return const_cast<Value *>(getUnderlyingObject(VConst, MaxLookup));
+}
+
+/// This method is similar to getUnderlyingObject except that it can
+/// look through phi and select instructions and return multiple objects.
+///
+/// If LoopInfo is passed, loop phis are further analyzed. If a pointer
+/// accesses different objects in each iteration, we don't look through the
+/// phi node. E.g. consider this loop nest:
+///
+/// int **A;
+/// for (i)
+/// for (j) {
+/// A[i][j] = A[i-1][j] * B[j]
+/// }
+///
+/// This is transformed by Load-PRE to stash away A[i] for the next iteration
+/// of the outer loop:
+///
+/// Curr = A[0]; // Prev_0
+/// for (i: 1..N) {
+/// Prev = Curr; // Prev = PHI (Prev_0, Curr)
+/// Curr = A[i];
+/// for (j: 0..N) {
+/// Curr[j] = Prev[j] * B[j]
+/// }
+/// }
+///
+/// Since A[i] and A[i-1] are independent pointers, getUnderlyingObjects
+/// should not assume that Curr and Prev share the same underlying object thus
+/// it shouldn't look through the phi above.
+void getUnderlyingObjects(const Value *V,
+ SmallVectorImpl<const Value *> &Objects,
+ LoopInfo *LI = nullptr, unsigned MaxLookup = 6);
+
+/// This is a wrapper around getUnderlyingObjects and adds support for basic
+/// ptrtoint+arithmetic+inttoptr sequences.
+bool getUnderlyingObjectsForCodeGen(const Value *V,
+ SmallVectorImpl<Value *> &Objects);
+
+/// Returns unique alloca where the value comes from, or nullptr.
+/// If OffsetZero is true check that V points to the begining of the alloca.
+AllocaInst *findAllocaForValue(Value *V, bool OffsetZero = false);
+inline const AllocaInst *findAllocaForValue(const Value *V,
+ bool OffsetZero = false) {
+ return findAllocaForValue(const_cast<Value *>(V), OffsetZero);
+}
+
+/// Return true if the only users of this pointer are lifetime markers.
+bool onlyUsedByLifetimeMarkers(const Value *V);
+
+/// Return true if the only users of this pointer are lifetime markers or
+/// droppable instructions.
+bool onlyUsedByLifetimeMarkersOrDroppableInsts(const Value *V);
+
+/// Return true if speculation of the given load must be suppressed to avoid
+/// ordering or interfering with an active sanitizer. If not suppressed,
+/// dereferenceability and alignment must be proven separately. Note: This
+/// is only needed for raw reasoning; if you use the interface below
+/// (isSafeToSpeculativelyExecute), this is handled internally.
+bool mustSuppressSpeculation(const LoadInst &LI);
+
+/// Return true if the instruction does not have any effects besides
+/// calculating the result and does not have undefined behavior.
+///
+/// This method never returns true for an instruction that returns true for
+/// mayHaveSideEffects; however, this method also does some other checks in
+/// addition. It checks for undefined behavior, like dividing by zero or
+/// loading from an invalid pointer (but not for undefined results, like a
+/// shift with a shift amount larger than the width of the result). It checks
+/// for malloc and alloca because speculatively executing them might cause a
+/// memory leak. It also returns false for instructions related to control
+/// flow, specifically terminators and PHI nodes.
+///
+/// If the CtxI is specified this method performs context-sensitive analysis
+/// and returns true if it is safe to execute the instruction immediately
+/// before the CtxI.
+///
+/// If the CtxI is NOT specified this method only looks at the instruction
+/// itself and its operands, so if this method returns true, it is safe to
+/// move the instruction as long as the correct dominance relationships for
+/// the operands and users hold.
+///
+/// This method can return true for instructions that read memory;
+/// for such instructions, moving them may change the resulting value.
+bool isSafeToSpeculativelyExecute(const Instruction *I,
+ const Instruction *CtxI = nullptr,
+ const DominatorTree *DT = nullptr,
+ const TargetLibraryInfo *TLI = nullptr);
+
+/// This returns the same result as isSafeToSpeculativelyExecute if Opcode is
+/// the actual opcode of Inst. If the provided and actual opcode differ, the
+/// function (virtually) overrides the opcode of Inst with the provided
+/// Opcode. There are come constraints in this case:
+/// * If Opcode has a fixed number of operands (eg, as binary operators do),
+/// then Inst has to have at least as many leading operands. The function
+/// will ignore all trailing operands beyond that number.
+/// * If Opcode allows for an arbitrary number of operands (eg, as CallInsts
+/// do), then all operands are considered.
+/// * The virtual instruction has to satisfy all typing rules of the provided
+/// Opcode.
+/// * This function is pessimistic in the following sense: If one actually
+/// materialized the virtual instruction, then isSafeToSpeculativelyExecute
+/// may say that the materialized instruction is speculatable whereas this
+/// function may have said that the instruction wouldn't be speculatable.
+/// This behavior is a shortcoming in the current implementation and not
+/// intentional.
+bool isSafeToSpeculativelyExecuteWithOpcode(
+ unsigned Opcode, const Instruction *Inst, const Instruction *CtxI = nullptr,
+ const DominatorTree *DT = nullptr, const TargetLibraryInfo *TLI = nullptr);
+
+/// Returns true if the result or effects of the given instructions \p I
+/// depend values not reachable through the def use graph.
+/// * Memory dependence arises for example if the instruction reads from
+/// memory or may produce effects or undefined behaviour. Memory dependent
+/// instructions generally cannot be reorderd with respect to other memory
+/// dependent instructions.
+/// * Control dependence arises for example if the instruction may fault
+/// if lifted above a throwing call or infinite loop.
+bool mayHaveNonDefUseDependency(const Instruction &I);
+
+/// Return true if it is an intrinsic that cannot be speculated but also
+/// cannot trap.
+bool isAssumeLikeIntrinsic(const Instruction *I);
+
+/// Return true if it is valid to use the assumptions provided by an
+/// assume intrinsic, I, at the point in the control-flow identified by the
+/// context instruction, CxtI.
+bool isValidAssumeForContext(const Instruction *I, const Instruction *CxtI,
+ const DominatorTree *DT = nullptr);
+
+enum class OverflowResult {
+ /// Always overflows in the direction of signed/unsigned min value.
+ AlwaysOverflowsLow,
+ /// Always overflows in the direction of signed/unsigned max value.
+ AlwaysOverflowsHigh,
+ /// May or may not overflow.
+ MayOverflow,
+ /// Never overflows.
+ NeverOverflows,
+};
+
+OverflowResult computeOverflowForUnsignedMul(const Value *LHS, const Value *RHS,
const DataLayout &DL,
AssumptionCache *AC,
const Instruction *CxtI,
const DominatorTree *DT,
bool UseInstrInfo = true);
- OverflowResult computeOverflowForUnsignedAdd(const Value *LHS,
- const Value *RHS,
- const DataLayout &DL,
- AssumptionCache *AC,
- const Instruction *CxtI,
- const DominatorTree *DT,
- bool UseInstrInfo = true);
- OverflowResult computeOverflowForSignedAdd(const Value *LHS, const Value *RHS,
+OverflowResult computeOverflowForSignedMul(const Value *LHS, const Value *RHS,
+ const DataLayout &DL,
+ AssumptionCache *AC,
+ const Instruction *CxtI,
+ const DominatorTree *DT,
+ bool UseInstrInfo = true);
+OverflowResult computeOverflowForUnsignedAdd(const Value *LHS, const Value *RHS,
const DataLayout &DL,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr);
- /// This version also leverages the sign bit of Add if known.
- OverflowResult computeOverflowForSignedAdd(const AddOperator *Add,
- const DataLayout &DL,
- AssumptionCache *AC = nullptr,
- const Instruction *CxtI = nullptr,
- const DominatorTree *DT = nullptr);
- OverflowResult computeOverflowForUnsignedSub(const Value *LHS, const Value *RHS,
- const DataLayout &DL,
- AssumptionCache *AC,
- const Instruction *CxtI,
- const DominatorTree *DT);
- OverflowResult computeOverflowForSignedSub(const Value *LHS, const Value *RHS,
+ AssumptionCache *AC,
+ const Instruction *CxtI,
+ const DominatorTree *DT,
+ bool UseInstrInfo = true);
+OverflowResult computeOverflowForSignedAdd(const Value *LHS, const Value *RHS,
+ const DataLayout &DL,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr);
+/// This version also leverages the sign bit of Add if known.
+OverflowResult computeOverflowForSignedAdd(const AddOperator *Add,
+ const DataLayout &DL,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CxtI = nullptr,
+ const DominatorTree *DT = nullptr);
+OverflowResult computeOverflowForUnsignedSub(const Value *LHS, const Value *RHS,
const DataLayout &DL,
AssumptionCache *AC,
const Instruction *CxtI,
const DominatorTree *DT);
-
- /// Returns true if the arithmetic part of the \p WO 's result is
- /// used only along the paths control dependent on the computation
- /// not overflowing, \p WO being an <op>.with.overflow intrinsic.
- bool isOverflowIntrinsicNoWrap(const WithOverflowInst *WO,
- const DominatorTree &DT);
-
-
- /// Determine the possible constant range of an integer or vector of integer
- /// value. This is intended as a cheap, non-recursive check.
- ConstantRange computeConstantRange(const Value *V, bool ForSigned,
- bool UseInstrInfo = true,
- AssumptionCache *AC = nullptr,
- const Instruction *CtxI = nullptr,
- const DominatorTree *DT = nullptr,
- unsigned Depth = 0);
-
- /// Return true if this function can prove that the instruction I will
- /// always transfer execution to one of its successors (including the next
- /// instruction that follows within a basic block). E.g. this is not
- /// guaranteed for function calls that could loop infinitely.
- ///
- /// In other words, this function returns false for instructions that may
- /// transfer execution or fail to transfer execution in a way that is not
- /// captured in the CFG nor in the sequence of instructions within a basic
- /// block.
- ///
- /// Undefined behavior is assumed not to happen, so e.g. division is
- /// guaranteed to transfer execution to the following instruction even
- /// though division by zero might cause undefined behavior.
- bool isGuaranteedToTransferExecutionToSuccessor(const Instruction *I);
-
- /// Returns true if this block does not contain a potential implicit exit.
- /// This is equivelent to saying that all instructions within the basic block
- /// are guaranteed to transfer execution to their successor within the basic
- /// block. This has the same assumptions w.r.t. undefined behavior as the
- /// instruction variant of this function.
- bool isGuaranteedToTransferExecutionToSuccessor(const BasicBlock *BB);
-
- /// Return true if every instruction in the range (Begin, End) is
- /// guaranteed to transfer execution to its static successor. \p ScanLimit
- /// bounds the search to avoid scanning huge blocks.
- bool isGuaranteedToTransferExecutionToSuccessor(
- BasicBlock::const_iterator Begin, BasicBlock::const_iterator End,
- unsigned ScanLimit = 32);
-
- /// Same as previous, but with range expressed via iterator_range.
- bool isGuaranteedToTransferExecutionToSuccessor(
- iterator_range<BasicBlock::const_iterator> Range,
- unsigned ScanLimit = 32);
-
- /// Return true if this function can prove that the instruction I
- /// is executed for every iteration of the loop L.
- ///
- /// Note that this currently only considers the loop header.
- bool isGuaranteedToExecuteForEveryIteration(const Instruction *I,
- const Loop *L);
-
- /// Return true if I yields poison or raises UB if any of its operands is
- /// poison.
- /// Formally, given I = `r = op v1 v2 .. vN`, propagatesPoison returns true
- /// if, for all i, r is evaluated to poison or op raises UB if vi = poison.
- /// If vi is a vector or an aggregate and r is a single value, any poison
- /// element in vi should make r poison or raise UB.
- /// To filter out operands that raise UB on poison, you can use
- /// getGuaranteedNonPoisonOp.
- bool propagatesPoison(const Operator *I);
-
- /// Insert operands of I into Ops such that I will trigger undefined behavior
- /// if I is executed and that operand has a poison value.
- void getGuaranteedNonPoisonOps(const Instruction *I,
+OverflowResult computeOverflowForSignedSub(const Value *LHS, const Value *RHS,
+ const DataLayout &DL,
+ AssumptionCache *AC,
+ const Instruction *CxtI,
+ const DominatorTree *DT);
+
+/// Returns true if the arithmetic part of the \p WO 's result is
+/// used only along the paths control dependent on the computation
+/// not overflowing, \p WO being an <op>.with.overflow intrinsic.
+bool isOverflowIntrinsicNoWrap(const WithOverflowInst *WO,
+ const DominatorTree &DT);
+
+/// Determine the possible constant range of an integer or vector of integer
+/// value. This is intended as a cheap, non-recursive check.
+ConstantRange computeConstantRange(const Value *V, bool ForSigned,
+ bool UseInstrInfo = true,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CtxI = nullptr,
+ const DominatorTree *DT = nullptr,
+ unsigned Depth = 0);
+
+/// Return true if this function can prove that the instruction I will
+/// always transfer execution to one of its successors (including the next
+/// instruction that follows within a basic block). E.g. this is not
+/// guaranteed for function calls that could loop infinitely.
+///
+/// In other words, this function returns false for instructions that may
+/// transfer execution or fail to transfer execution in a way that is not
+/// captured in the CFG nor in the sequence of instructions within a basic
+/// block.
+///
+/// Undefined behavior is assumed not to happen, so e.g. division is
+/// guaranteed to transfer execution to the following instruction even
+/// though division by zero might cause undefined behavior.
+bool isGuaranteedToTransferExecutionToSuccessor(const Instruction *I);
+
+/// Returns true if this block does not contain a potential implicit exit.
+/// This is equivelent to saying that all instructions within the basic block
+/// are guaranteed to transfer execution to their successor within the basic
+/// block. This has the same assumptions w.r.t. undefined behavior as the
+/// instruction variant of this function.
+bool isGuaranteedToTransferExecutionToSuccessor(const BasicBlock *BB);
+
+/// Return true if every instruction in the range (Begin, End) is
+/// guaranteed to transfer execution to its static successor. \p ScanLimit
+/// bounds the search to avoid scanning huge blocks.
+bool isGuaranteedToTransferExecutionToSuccessor(
+ BasicBlock::const_iterator Begin, BasicBlock::const_iterator End,
+ unsigned ScanLimit = 32);
+
+/// Same as previous, but with range expressed via iterator_range.
+bool isGuaranteedToTransferExecutionToSuccessor(
+ iterator_range<BasicBlock::const_iterator> Range, unsigned ScanLimit = 32);
+
+/// Return true if this function can prove that the instruction I
+/// is executed for every iteration of the loop L.
+///
+/// Note that this currently only considers the loop header.
+bool isGuaranteedToExecuteForEveryIteration(const Instruction *I,
+ const Loop *L);
+
+/// Return true if I yields poison or raises UB if any of its operands is
+/// poison.
+/// Formally, given I = `r = op v1 v2 .. vN`, propagatesPoison returns true
+/// if, for all i, r is evaluated to poison or op raises UB if vi = poison.
+/// If vi is a vector or an aggregate and r is a single value, any poison
+/// element in vi should make r poison or raise UB.
+/// To filter out operands that raise UB on poison, you can use
+/// getGuaranteedNonPoisonOp.
+bool propagatesPoison(const Operator *I);
+
+/// Insert operands of I into Ops such that I will trigger undefined behavior
+/// if I is executed and that operand has a poison value.
+void getGuaranteedNonPoisonOps(const Instruction *I,
+ SmallPtrSetImpl<const Value *> &Ops);
+/// Insert operands of I into Ops such that I will trigger undefined behavior
+/// if I is executed and that operand is not a well-defined value
+/// (i.e. has undef bits or poison).
+void getGuaranteedWellDefinedOps(const Instruction *I,
SmallPtrSetImpl<const Value *> &Ops);
- /// Insert operands of I into Ops such that I will trigger undefined behavior
- /// if I is executed and that operand is not a well-defined value
- /// (i.e. has undef bits or poison).
- void getGuaranteedWellDefinedOps(const Instruction *I,
- SmallPtrSetImpl<const Value *> &Ops);
-
- /// Return true if the given instruction must trigger undefined behavior
- /// when I is executed with any operands which appear in KnownPoison holding
- /// a poison value at the point of execution.
- bool mustTriggerUB(const Instruction *I,
- const SmallSet<const Value *, 16>& KnownPoison);
-
- /// Return true if this function can prove that if Inst is executed
- /// and yields a poison value or undef bits, then that will trigger
- /// undefined behavior.
- ///
- /// Note that this currently only considers the basic block that is
- /// the parent of Inst.
- bool programUndefinedIfUndefOrPoison(const Instruction *Inst);
- bool programUndefinedIfPoison(const Instruction *Inst);
-
- /// canCreateUndefOrPoison returns true if Op can create undef or poison from
- /// non-undef & non-poison operands.
- /// For vectors, canCreateUndefOrPoison returns true if there is potential
- /// poison or undef in any element of the result when vectors without
- /// undef/poison poison are given as operands.
- /// For example, given `Op = shl <2 x i32> %x, <0, 32>`, this function returns
- /// true. If Op raises immediate UB but never creates poison or undef
- /// (e.g. sdiv I, 0), canCreatePoison returns false.
- ///
- /// \p ConsiderFlags controls whether poison producing flags on the
- /// instruction are considered. This can be used to see if the instruction
- /// could still introduce undef or poison even without poison generating flags
- /// which might be on the instruction. (i.e. could the result of
- /// Op->dropPoisonGeneratingFlags() still create poison or undef)
- ///
- /// canCreatePoison returns true if Op can create poison from non-poison
- /// operands.
- bool canCreateUndefOrPoison(const Operator *Op, bool ConsiderFlags = true);
- bool canCreatePoison(const Operator *Op, bool ConsiderFlags = true);
-
- /// Return true if V is poison given that ValAssumedPoison is already poison.
- /// For example, if ValAssumedPoison is `icmp X, 10` and V is `icmp X, 5`,
- /// impliesPoison returns true.
- bool impliesPoison(const Value *ValAssumedPoison, const Value *V);
-
- /// Return true if this function can prove that V does not have undef bits
- /// and is never poison. If V is an aggregate value or vector, check whether
- /// all elements (except padding) are not undef or poison.
- /// Note that this is different from canCreateUndefOrPoison because the
- /// function assumes Op's operands are not poison/undef.
- ///
- /// If CtxI and DT are specified this method performs flow-sensitive analysis
- /// and returns true if it is guaranteed to be never undef or poison
- /// immediately before the CtxI.
- bool isGuaranteedNotToBeUndefOrPoison(const Value *V,
- AssumptionCache *AC = nullptr,
- const Instruction *CtxI = nullptr,
- const DominatorTree *DT = nullptr,
- unsigned Depth = 0);
- bool isGuaranteedNotToBePoison(const Value *V, AssumptionCache *AC = nullptr,
- const Instruction *CtxI = nullptr,
- const DominatorTree *DT = nullptr,
- unsigned Depth = 0);
-
- /// Specific patterns of select instructions we can match.
- enum SelectPatternFlavor {
- SPF_UNKNOWN = 0,
- SPF_SMIN, /// Signed minimum
- SPF_UMIN, /// Unsigned minimum
- SPF_SMAX, /// Signed maximum
- SPF_UMAX, /// Unsigned maximum
- SPF_FMINNUM, /// Floating point minnum
- SPF_FMAXNUM, /// Floating point maxnum
- SPF_ABS, /// Absolute value
- SPF_NABS /// Negated absolute value
- };
-
- /// Behavior when a floating point min/max is given one NaN and one
- /// non-NaN as input.
- enum SelectPatternNaNBehavior {
- SPNB_NA = 0, /// NaN behavior not applicable.
- SPNB_RETURNS_NAN, /// Given one NaN input, returns the NaN.
- SPNB_RETURNS_OTHER, /// Given one NaN input, returns the non-NaN.
- SPNB_RETURNS_ANY /// Given one NaN input, can return either (or
- /// it has been determined that no operands can
- /// be NaN).
- };
-
- struct SelectPatternResult {
- SelectPatternFlavor Flavor;
- SelectPatternNaNBehavior NaNBehavior; /// Only applicable if Flavor is
- /// SPF_FMINNUM or SPF_FMAXNUM.
- bool Ordered; /// When implementing this min/max pattern as
- /// fcmp; select, does the fcmp have to be
- /// ordered?
-
- /// Return true if \p SPF is a min or a max pattern.
- static bool isMinOrMax(SelectPatternFlavor SPF) {
- return SPF != SPF_UNKNOWN && SPF != SPF_ABS && SPF != SPF_NABS;
- }
- };
-
- /// Pattern match integer [SU]MIN, [SU]MAX and ABS idioms, returning the kind
- /// and providing the out parameter results if we successfully match.
- ///
- /// For ABS/NABS, LHS will be set to the input to the abs idiom. RHS will be
- /// the negation instruction from the idiom.
- ///
- /// If CastOp is not nullptr, also match MIN/MAX idioms where the type does
- /// not match that of the original select. If this is the case, the cast
- /// operation (one of Trunc,SExt,Zext) that must be done to transform the
- /// type of LHS and RHS into the type of V is returned in CastOp.
- ///
- /// For example:
- /// %1 = icmp slt i32 %a, i32 4
- /// %2 = sext i32 %a to i64
- /// %3 = select i1 %1, i64 %2, i64 4
- ///
- /// -> LHS = %a, RHS = i32 4, *CastOp = Instruction::SExt
- ///
- SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS,
- Instruction::CastOps *CastOp = nullptr,
- unsigned Depth = 0);
-
- inline SelectPatternResult
- matchSelectPattern(const Value *V, const Value *&LHS, const Value *&RHS) {
- Value *L = const_cast<Value *>(LHS);
- Value *R = const_cast<Value *>(RHS);
- auto Result = matchSelectPattern(const_cast<Value *>(V), L, R);
- LHS = L;
- RHS = R;
- return Result;
- }
- /// Determine the pattern that a select with the given compare as its
- /// predicate and given values as its true/false operands would match.
- SelectPatternResult matchDecomposedSelectPattern(
- CmpInst *CmpI, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS,
- Instruction::CastOps *CastOp = nullptr, unsigned Depth = 0);
-
- /// Return the canonical comparison predicate for the specified
- /// minimum/maximum flavor.
- CmpInst::Predicate getMinMaxPred(SelectPatternFlavor SPF,
- bool Ordered = false);
-
- /// Return the inverse minimum/maximum flavor of the specified flavor.
- /// For example, signed minimum is the inverse of signed maximum.
- SelectPatternFlavor getInverseMinMaxFlavor(SelectPatternFlavor SPF);
-
- Intrinsic::ID getInverseMinMaxIntrinsic(Intrinsic::ID MinMaxID);
-
- /// Return the canonical inverse comparison predicate for the specified
- /// minimum/maximum flavor.
- CmpInst::Predicate getInverseMinMaxPred(SelectPatternFlavor SPF);
-
- /// Return the minimum or maximum constant value for the specified integer
- /// min/max flavor and type.
- APInt getMinMaxLimit(SelectPatternFlavor SPF, unsigned BitWidth);
-
- /// Check if the values in \p VL are select instructions that can be converted
- /// to a min or max (vector) intrinsic. Returns the intrinsic ID, if such a
- /// conversion is possible, together with a bool indicating whether all select
- /// conditions are only used by the selects. Otherwise return
- /// Intrinsic::not_intrinsic.
- std::pair<Intrinsic::ID, bool>
- canConvertToMinOrMaxIntrinsic(ArrayRef<Value *> VL);
-
- /// Attempt to match a simple first order recurrence cycle of the form:
- /// %iv = phi Ty [%Start, %Entry], [%Inc, %backedge]
- /// %inc = binop %iv, %step
- /// OR
- /// %iv = phi Ty [%Start, %Entry], [%Inc, %backedge]
- /// %inc = binop %step, %iv
- ///
- /// A first order recurrence is a formula with the form: X_n = f(X_(n-1))
- ///
- /// A couple of notes on subtleties in that definition:
- /// * The Step does not have to be loop invariant. In math terms, it can
- /// be a free variable. We allow recurrences with both constant and
- /// variable coefficients. Callers may wish to filter cases where Step
- /// does not dominate P.
- /// * For non-commutative operators, we will match both forms. This
- /// results in some odd recurrence structures. Callers may wish to filter
- /// out recurrences where the phi is not the LHS of the returned operator.
- /// * Because of the structure matched, the caller can assume as a post
- /// condition of the match the presence of a Loop with P's parent as it's
- /// header *except* in unreachable code. (Dominance decays in unreachable
- /// code.)
- ///
- /// NOTE: This is intentional simple. If you want the ability to analyze
- /// non-trivial loop conditons, see ScalarEvolution instead.
- bool matchSimpleRecurrence(const PHINode *P, BinaryOperator *&BO,
- Value *&Start, Value *&Step);
-
- /// Analogous to the above, but starting from the binary operator
- bool matchSimpleRecurrence(const BinaryOperator *I, PHINode *&P,
- Value *&Start, Value *&Step);
-
- /// Return true if RHS is known to be implied true by LHS. Return false if
- /// RHS is known to be implied false by LHS. Otherwise, return None if no
- /// implication can be made.
- /// A & B must be i1 (boolean) values or a vector of such values. Note that
- /// the truth table for implication is the same as <=u on i1 values (but not
- /// <=s!). The truth table for both is:
- /// | T | F (B)
- /// T | T | F
- /// F | T | T
- /// (A)
- Optional<bool> isImpliedCondition(const Value *LHS, const Value *RHS,
- const DataLayout &DL, bool LHSIsTrue = true,
- unsigned Depth = 0);
- Optional<bool> isImpliedCondition(const Value *LHS,
- CmpInst::Predicate RHSPred,
- const Value *RHSOp0, const Value *RHSOp1,
- const DataLayout &DL, bool LHSIsTrue = true,
- unsigned Depth = 0);
-
- /// Return the boolean condition value in the context of the given instruction
- /// if it is known based on dominating conditions.
- Optional<bool> isImpliedByDomCondition(const Value *Cond,
- const Instruction *ContextI,
- const DataLayout &DL);
- Optional<bool> isImpliedByDomCondition(CmpInst::Predicate Pred,
- const Value *LHS, const Value *RHS,
- const Instruction *ContextI,
- const DataLayout &DL);
-
- /// If Ptr1 is provably equal to Ptr2 plus a constant offset, return that
- /// offset. For example, Ptr1 might be &A[42], and Ptr2 might be &A[40]. In
- /// this case offset would be -8.
- Optional<int64_t> isPointerOffset(const Value *Ptr1, const Value *Ptr2,
- const DataLayout &DL);
+/// Return true if the given instruction must trigger undefined behavior
+/// when I is executed with any operands which appear in KnownPoison holding
+/// a poison value at the point of execution.
+bool mustTriggerUB(const Instruction *I,
+ const SmallSet<const Value *, 16> &KnownPoison);
+
+/// Return true if this function can prove that if Inst is executed
+/// and yields a poison value or undef bits, then that will trigger
+/// undefined behavior.
+///
+/// Note that this currently only considers the basic block that is
+/// the parent of Inst.
+bool programUndefinedIfUndefOrPoison(const Instruction *Inst);
+bool programUndefinedIfPoison(const Instruction *Inst);
+
+/// canCreateUndefOrPoison returns true if Op can create undef or poison from
+/// non-undef & non-poison operands.
+/// For vectors, canCreateUndefOrPoison returns true if there is potential
+/// poison or undef in any element of the result when vectors without
+/// undef/poison poison are given as operands.
+/// For example, given `Op = shl <2 x i32> %x, <0, 32>`, this function returns
+/// true. If Op raises immediate UB but never creates poison or undef
+/// (e.g. sdiv I, 0), canCreatePoison returns false.
+///
+/// \p ConsiderFlags controls whether poison producing flags on the
+/// instruction are considered. This can be used to see if the instruction
+/// could still introduce undef or poison even without poison generating flags
+/// which might be on the instruction. (i.e. could the result of
+/// Op->dropPoisonGeneratingFlags() still create poison or undef)
+///
+/// canCreatePoison returns true if Op can create poison from non-poison
+/// operands.
+bool canCreateUndefOrPoison(const Operator *Op, bool ConsiderFlags = true);
+bool canCreatePoison(const Operator *Op, bool ConsiderFlags = true);
+
+/// Return true if V is poison given that ValAssumedPoison is already poison.
+/// For example, if ValAssumedPoison is `icmp X, 10` and V is `icmp X, 5`,
+/// impliesPoison returns true.
+bool impliesPoison(const Value *ValAssumedPoison, const Value *V);
+
+/// Return true if this function can prove that V does not have undef bits
+/// and is never poison. If V is an aggregate value or vector, check whether
+/// all elements (except padding) are not undef or poison.
+/// Note that this is different from canCreateUndefOrPoison because the
+/// function assumes Op's operands are not poison/undef.
+///
+/// If CtxI and DT are specified this method performs flow-sensitive analysis
+/// and returns true if it is guaranteed to be never undef or poison
+/// immediately before the CtxI.
+bool isGuaranteedNotToBeUndefOrPoison(const Value *V,
+ AssumptionCache *AC = nullptr,
+ const Instruction *CtxI = nullptr,
+ const DominatorTree *DT = nullptr,
+ unsigned Depth = 0);
+bool isGuaranteedNotToBePoison(const Value *V, AssumptionCache *AC = nullptr,
+ const Instruction *CtxI = nullptr,
+ const DominatorTree *DT = nullptr,
+ unsigned Depth = 0);
+
+/// Specific patterns of select instructions we can match.
+enum SelectPatternFlavor {
+ SPF_UNKNOWN = 0,
+ SPF_SMIN, /// Signed minimum
+ SPF_UMIN, /// Unsigned minimum
+ SPF_SMAX, /// Signed maximum
+ SPF_UMAX, /// Unsigned maximum
+ SPF_FMINNUM, /// Floating point minnum
+ SPF_FMAXNUM, /// Floating point maxnum
+ SPF_ABS, /// Absolute value
+ SPF_NABS /// Negated absolute value
+};
+
+/// Behavior when a floating point min/max is given one NaN and one
+/// non-NaN as input.
+enum SelectPatternNaNBehavior {
+ SPNB_NA = 0, /// NaN behavior not applicable.
+ SPNB_RETURNS_NAN, /// Given one NaN input, returns the NaN.
+ SPNB_RETURNS_OTHER, /// Given one NaN input, returns the non-NaN.
+ SPNB_RETURNS_ANY /// Given one NaN input, can return either (or
+ /// it has been determined that no operands can
+ /// be NaN).
+};
+
+struct SelectPatternResult {
+ SelectPatternFlavor Flavor;
+ SelectPatternNaNBehavior NaNBehavior; /// Only applicable if Flavor is
+ /// SPF_FMINNUM or SPF_FMAXNUM.
+ bool Ordered; /// When implementing this min/max pattern as
+ /// fcmp; select, does the fcmp have to be
+ /// ordered?
+
+ /// Return true if \p SPF is a min or a max pattern.
+ static bool isMinOrMax(SelectPatternFlavor SPF) {
+ return SPF != SPF_UNKNOWN && SPF != SPF_ABS && SPF != SPF_NABS;
+ }
+};
+
+/// Pattern match integer [SU]MIN, [SU]MAX and ABS idioms, returning the kind
+/// and providing the out parameter results if we successfully match.
+///
+/// For ABS/NABS, LHS will be set to the input to the abs idiom. RHS will be
+/// the negation instruction from the idiom.
+///
+/// If CastOp is not nullptr, also match MIN/MAX idioms where the type does
+/// not match that of the original select. If this is the case, the cast
+/// operation (one of Trunc,SExt,Zext) that must be done to transform the
+/// type of LHS and RHS into the type of V is returned in CastOp.
+///
+/// For example:
+/// %1 = icmp slt i32 %a, i32 4
+/// %2 = sext i32 %a to i64
+/// %3 = select i1 %1, i64 %2, i64 4
+///
+/// -> LHS = %a, RHS = i32 4, *CastOp = Instruction::SExt
+///
+SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS,
+ Instruction::CastOps *CastOp = nullptr,
+ unsigned Depth = 0);
+
+inline SelectPatternResult matchSelectPattern(const Value *V, const Value *&LHS,
+ const Value *&RHS) {
+ Value *L = const_cast<Value *>(LHS);
+ Value *R = const_cast<Value *>(RHS);
+ auto Result = matchSelectPattern(const_cast<Value *>(V), L, R);
+ LHS = L;
+ RHS = R;
+ return Result;
+}
+
+/// Determine the pattern that a select with the given compare as its
+/// predicate and given values as its true/false operands would match.
+SelectPatternResult matchDecomposedSelectPattern(
+ CmpInst *CmpI, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS,
+ Instruction::CastOps *CastOp = nullptr, unsigned Depth = 0);
+
+/// Return the canonical comparison predicate for the specified
+/// minimum/maximum flavor.
+CmpInst::Predicate getMinMaxPred(SelectPatternFlavor SPF, bool Ordered = false);
+
+/// Return the inverse minimum/maximum flavor of the specified flavor.
+/// For example, signed minimum is the inverse of signed maximum.
+SelectPatternFlavor getInverseMinMaxFlavor(SelectPatternFlavor SPF);
+
+Intrinsic::ID getInverseMinMaxIntrinsic(Intrinsic::ID MinMaxID);
+
+/// Return the canonical inverse comparison predicate for the specified
+/// minimum/maximum flavor.
+CmpInst::Predicate getInverseMinMaxPred(SelectPatternFlavor SPF);
+
+/// Return the minimum or maximum constant value for the specified integer
+/// min/max flavor and type.
+APInt getMinMaxLimit(SelectPatternFlavor SPF, unsigned BitWidth);
+
+/// Check if the values in \p VL are select instructions that can be converted
+/// to a min or max (vector) intrinsic. Returns the intrinsic ID, if such a
+/// conversion is possible, together with a bool indicating whether all select
+/// conditions are only used by the selects. Otherwise return
+/// Intrinsic::not_intrinsic.
+std::pair<Intrinsic::ID, bool>
+canConvertToMinOrMaxIntrinsic(ArrayRef<Value *> VL);
+
+/// Attempt to match a simple first order recurrence cycle of the form:
+/// %iv = phi Ty [%Start, %Entry], [%Inc, %backedge]
+/// %inc = binop %iv, %step
+/// OR
+/// %iv = phi Ty [%Start, %Entry], [%Inc, %backedge]
+/// %inc = binop %step, %iv
+///
+/// A first order recurrence is a formula with the form: X_n = f(X_(n-1))
+///
+/// A couple of notes on subtleties in that definition:
+/// * The Step does not have to be loop invariant. In math terms, it can
+/// be a free variable. We allow recurrences with both constant and
+/// variable coefficients. Callers may wish to filter cases where Step
+/// does not dominate P.
+/// * For non-commutative operators, we will match both forms. This
+/// results in some odd recurrence structures. Callers may wish to filter
+/// out recurrences where the phi is not the LHS of the returned operator.
+/// * Because of the structure matched, the caller can assume as a post
+/// condition of the match the presence of a Loop with P's parent as it's
+/// header *except* in unreachable code. (Dominance decays in unreachable
+/// code.)
+///
+/// NOTE: This is intentional simple. If you want the ability to analyze
+/// non-trivial loop conditons, see ScalarEvolution instead.
+bool matchSimpleRecurrence(const PHINode *P, BinaryOperator *&BO, Value *&Start,
+ Value *&Step);
+
+/// Analogous to the above, but starting from the binary operator
+bool matchSimpleRecurrence(const BinaryOperator *I, PHINode *&P, Value *&Start,
+ Value *&Step);
+
+/// Return true if RHS is known to be implied true by LHS. Return false if
+/// RHS is known to be implied false by LHS. Otherwise, return None if no
+/// implication can be made.
+/// A & B must be i1 (boolean) values or a vector of such values. Note that
+/// the truth table for implication is the same as <=u on i1 values (but not
+/// <=s!). The truth table for both is:
+/// | T | F (B)
+/// T | T | F
+/// F | T | T
+/// (A)
+Optional<bool> isImpliedCondition(const Value *LHS, const Value *RHS,
+ const DataLayout &DL, bool LHSIsTrue = true,
+ unsigned Depth = 0);
+Optional<bool> isImpliedCondition(const Value *LHS, CmpInst::Predicate RHSPred,
+ const Value *RHSOp0, const Value *RHSOp1,
+ const DataLayout &DL, bool LHSIsTrue = true,
+ unsigned Depth = 0);
+
+/// Return the boolean condition value in the context of the given instruction
+/// if it is known based on dominating conditions.
+Optional<bool> isImpliedByDomCondition(const Value *Cond,
+ const Instruction *ContextI,
+ const DataLayout &DL);
+Optional<bool> isImpliedByDomCondition(CmpInst::Predicate Pred,
+ const Value *LHS, const Value *RHS,
+ const Instruction *ContextI,
+ const DataLayout &DL);
+
+/// If Ptr1 is provably equal to Ptr2 plus a constant offset, return that
+/// offset. For example, Ptr1 might be &A[42], and Ptr2 might be &A[40]. In
+/// this case offset would be -8.
+Optional<int64_t> isPointerOffset(const Value *Ptr1, const Value *Ptr2,
+ const DataLayout &DL);
} // end namespace llvm
#endif // LLVM_ANALYSIS_VALUETRACKING_H
projects / platform / upstream / llvm.git / commitdiff