#ifndef LLVM_ANALYSIS_VALUETRACKING_H
#define LLVM_ANALYSIS_VALUETRACKING_H
+#include "llvm/ADT/ArrayRef.h"
#include "llvm/Support/DataTypes.h"
-#include <string>
namespace llvm {
class Value;
class Instruction;
class APInt;
- class TargetData;
-
+ class DataLayout;
+ class StringRef;
+ class MDNode;
+ class TargetLibraryInfo;
+
/// ComputeMaskedBits - Determine which of the bits specified in Mask are
/// known to be either zero or one and return them in the KnownZero/KnownOne
/// bit sets. This code only analyzes bits in Mask, in order to short-circuit
/// processing.
- void ComputeMaskedBits(Value *V, const APInt &Mask, APInt &KnownZero,
- APInt &KnownOne, TargetData *TD = 0,
- unsigned Depth = 0);
-
+ ///
+ /// 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
+ /// 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.
+ void ComputeMaskedBits(Value *V, APInt &KnownZero, APInt &KnownOne,
+ const DataLayout *TD = 0, unsigned Depth = 0);
+ void computeMaskedBitsLoad(const MDNode &Ranges, APInt &KnownZero);
+
+ /// ComputeSignBit - Determine whether the sign bit is known to be zero or
+ /// one. Convenience wrapper around ComputeMaskedBits.
+ void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
+ const DataLayout *TD = 0, unsigned Depth = 0);
+
+ /// isKnownToBeAPowerOfTwo - 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
+ /// returns true if the given value is either a power of two or zero.
+ bool isKnownToBeAPowerOfTwo(Value *V, bool OrZero = false, unsigned Depth = 0);
+
+ /// 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 = 0, unsigned Depth = 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.
+ ///
+ /// 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
+ /// 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,
- TargetData *TD = 0, unsigned Depth = 0);
+ const DataLayout *TD = 0, unsigned Depth = 0);
/// ComputeNumSignBits - Return the number of times the sign bit of the
///
/// 'Op' must have a scalar integer type.
///
- unsigned ComputeNumSignBits(Value *Op, TargetData *TD = 0,
+ unsigned ComputeNumSignBits(Value *Op, const DataLayout *TD = 0,
unsigned Depth = 0);
+ /// 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. Also, if V can be
+ /// simplified to an integer, then the simplified V is returned in Val. Look
+ /// through sext only if LookThroughSExt=true.
+ bool ComputeMultiple(Value *V, unsigned Base, Value *&Multiple,
+ bool LookThroughSExt = false,
+ unsigned Depth = 0);
+
/// CannotBeNegativeZero - Return true if we can prove that the specified FP
/// value is never equal to -0.0.
///
bool CannotBeNegativeZero(const Value *V, unsigned Depth = 0);
- /// FindScalarValue - Given an aggregrate and an sequence of indices, see if
+ /// 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
+ /// 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.
+ Value *isBytewiseValue(Value *V);
+
+ /// FindInsertedValue - 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.
///
/// If InsertBefore is not null, this function will duplicate (modified)
/// insertvalues when a part of a nested struct is extracted.
Value *FindInsertedValue(Value *V,
- const unsigned *idx_begin,
- const unsigned *idx_end,
+ ArrayRef<unsigned> idx_range,
Instruction *InsertBefore = 0);
- /// This is a convenience wrapper for finding values indexed by a single index
- /// only.
- inline Value *FindInsertedValue(Value *V, const unsigned Idx,
- Instruction *InsertBefore = 0) {
- const unsigned Idxs[1] = { Idx };
- return FindInsertedValue(V, &Idxs[0], &Idxs[1], InsertBefore);
+ /// 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.
+ Value *GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
+ const DataLayout *TD);
+ static inline const Value *
+ GetPointerBaseWithConstantOffset(const Value *Ptr, int64_t &Offset,
+ const DataLayout *TD) {
+ return GetPointerBaseWithConstantOffset(const_cast<Value*>(Ptr), Offset,TD);
}
- /// GetConstantStringInfo - This function computes the length of a
- /// null-terminated C string pointed to by V. If successful, it returns the
- /// string. If unsuccessful, it returns NUL. If StopAtNul is set to true
- /// (the default), the returned string is truncated by a nul character in the
- /// global. If StopAtNul is false, the nul character is included in the
- /// result string.
- const char *GetConstantStringInfo(Value *V, uint64_t Offset = 0,
- bool StopAtNul = true);
+ /// 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
+ /// does not include the trailing nul character by default. If TrimAtNul is
+ /// set to false, then this returns any trailing nul 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);
+
+ /// GetStringLength - 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(Value *V);
+
+ /// GetUnderlyingObject - 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.
+ Value *GetUnderlyingObject(Value *V, const DataLayout *TD = 0,
+ unsigned MaxLookup = 6);
+ static inline const Value *
+ GetUnderlyingObject(const Value *V, const DataLayout *TD = 0,
+ unsigned MaxLookup = 6) {
+ return GetUnderlyingObject(const_cast<Value *>(V), TD, MaxLookup);
+ }
+
+ /// GetUnderlyingObjects - This method is similar to GetUnderlyingObject
+ /// except that it can look through phi and select instructions and return
+ /// multiple objects.
+ void GetUnderlyingObjects(Value *V,
+ SmallVectorImpl<Value *> &Objects,
+ const DataLayout *TD = 0,
+ unsigned MaxLookup = 6);
+
+ /// onlyUsedByLifetimeMarkers - Return true if the only users of this pointer
+ /// are lifetime markers.
+ bool onlyUsedByLifetimeMarkers(const Value *V);
+
+ /// isSafeToSpeculativelyExecute - 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.
+ ///
+ /// 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.
+ /// However, this method can return true for instructions that read memory;
+ /// for such instructions, moving them may change the resulting value.
+ bool isSafeToSpeculativelyExecute(const Value *V,
+ const DataLayout *TD = 0);
+
+ /// isKnownNonNull - Return true if this pointer couldn't possibly be null by
+ /// its definition. This returns true for allocas, non-extern-weak globals
+ /// and byval arguments.
+ bool isKnownNonNull(const Value *V, const TargetLibraryInfo *TLI = 0);
+
} // end namespace llvm
#endif
projects / oota-llvm.git / blobdiff