1 //===- llvm/Analysis/ValueTracking.h - Walk computations --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains routines that help analyze properties that chains of
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_VALUETRACKING_H
16 #define LLVM_ANALYSIS_VALUETRACKING_H
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/ADT/Optional.h"
20 #include "llvm/IR/CallSite.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/Instruction.h"
23 #include "llvm/IR/Intrinsics.h"
31 class AssumptionCache;
40 class OptimizationRemarkEmitter;
42 class TargetLibraryInfo;
45 /// Determine which bits of V are known to be either zero or one and return
46 /// them in the KnownZero/KnownOne bit sets.
48 /// This function is defined on values with integer type, values with pointer
49 /// type, and vectors of integers. In the case
50 /// where V is a vector, the known zero and known one values are the
51 /// same width as the vector element, and the bit is set only if it is true
52 /// for all of the elements in the vector.
53 void computeKnownBits(const Value *V, KnownBits &Known,
54 const DataLayout &DL, unsigned Depth = 0,
55 AssumptionCache *AC = nullptr,
56 const Instruction *CxtI = nullptr,
57 const DominatorTree *DT = nullptr,
58 OptimizationRemarkEmitter *ORE = nullptr,
59 bool UseInstrInfo = true);
61 /// Returns the known bits rather than passing by reference.
62 KnownBits computeKnownBits(const Value *V, const DataLayout &DL,
63 unsigned Depth = 0, AssumptionCache *AC = nullptr,
64 const Instruction *CxtI = nullptr,
65 const DominatorTree *DT = nullptr,
66 OptimizationRemarkEmitter *ORE = nullptr,
67 bool UseInstrInfo = true);
69 /// Compute known bits from the range metadata.
70 /// \p KnownZero the set of bits that are known to be zero
71 /// \p KnownOne the set of bits that are known to be one
72 void computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
75 /// Return true if LHS and RHS have no common bits set.
76 bool haveNoCommonBitsSet(const Value *LHS, const Value *RHS,
78 AssumptionCache *AC = nullptr,
79 const Instruction *CxtI = nullptr,
80 const DominatorTree *DT = nullptr,
81 bool UseInstrInfo = true);
83 /// Return true if the given value is known to have exactly one bit set when
84 /// defined. For vectors return true if every element is known to be a power
85 /// of two when defined. Supports values with integer or pointer type and
86 /// vectors of integers. If 'OrZero' is set, then return true if the given
87 /// value is either a power of two or zero.
88 bool isKnownToBeAPowerOfTwo(const Value *V, const DataLayout &DL,
89 bool OrZero = false, unsigned Depth = 0,
90 AssumptionCache *AC = nullptr,
91 const Instruction *CxtI = nullptr,
92 const DominatorTree *DT = nullptr,
93 bool UseInstrInfo = true);
95 bool isOnlyUsedInZeroEqualityComparison(const Instruction *CxtI);
97 /// Return true if the given value is known to be non-zero when defined. For
98 /// vectors, return true if every element is known to be non-zero when
99 /// defined. For pointers, if the context instruction and dominator tree are
100 /// specified, perform context-sensitive analysis and return true if the
101 /// pointer couldn't possibly be null at the specified instruction.
102 /// Supports values with integer or pointer type and vectors of integers.
103 bool isKnownNonZero(const Value *V, const DataLayout &DL, unsigned Depth = 0,
104 AssumptionCache *AC = nullptr,
105 const Instruction *CxtI = nullptr,
106 const DominatorTree *DT = nullptr,
107 bool UseInstrInfo = true);
109 /// Return true if the two given values are negation.
110 /// Currently can recoginze Value pair:
111 /// 1: <X, Y> if X = sub (0, Y) or Y = sub (0, X)
112 /// 2: <X, Y> if X = sub (A, B) and Y = sub (B, A)
113 bool isKnownNegation(const Value *X, const Value *Y, bool NeedNSW = false);
115 /// Returns true if the give value is known to be non-negative.
116 bool isKnownNonNegative(const Value *V, const DataLayout &DL,
118 AssumptionCache *AC = nullptr,
119 const Instruction *CxtI = nullptr,
120 const DominatorTree *DT = nullptr,
121 bool UseInstrInfo = true);
123 /// Returns true if the given value is known be positive (i.e. non-negative
125 bool isKnownPositive(const Value *V, const DataLayout &DL, unsigned Depth = 0,
126 AssumptionCache *AC = nullptr,
127 const Instruction *CxtI = nullptr,
128 const DominatorTree *DT = nullptr,
129 bool UseInstrInfo = true);
131 /// Returns true if the given value is known be negative (i.e. non-positive
133 bool isKnownNegative(const Value *V, const DataLayout &DL, unsigned Depth = 0,
134 AssumptionCache *AC = nullptr,
135 const Instruction *CxtI = nullptr,
136 const DominatorTree *DT = nullptr,
137 bool UseInstrInfo = true);
139 /// Return true if the given values are known to be non-equal when defined.
140 /// Supports scalar integer types only.
141 bool isKnownNonEqual(const Value *V1, const Value *V2, const DataLayout &DL,
142 AssumptionCache *AC = nullptr,
143 const Instruction *CxtI = nullptr,
144 const DominatorTree *DT = nullptr,
145 bool UseInstrInfo = true);
147 /// Return true if 'V & Mask' is known to be zero. We use this predicate to
148 /// simplify operations downstream. Mask is known to be zero for bits that V
151 /// This function is defined on values with integer type, values with pointer
152 /// type, and vectors of integers. In the case
153 /// where V is a vector, the mask, known zero, and known one values are the
154 /// same width as the vector element, and the bit is set only if it is true
155 /// for all of the elements in the vector.
156 bool MaskedValueIsZero(const Value *V, const APInt &Mask,
157 const DataLayout &DL,
158 unsigned Depth = 0, AssumptionCache *AC = nullptr,
159 const Instruction *CxtI = nullptr,
160 const DominatorTree *DT = nullptr,
161 bool UseInstrInfo = true);
163 /// Return the number of times the sign bit of the register is replicated into
164 /// the other bits. We know that at least 1 bit is always equal to the sign
165 /// bit (itself), but other cases can give us information. For example,
166 /// immediately after an "ashr X, 2", we know that the top 3 bits are all
167 /// equal to each other, so we return 3. For vectors, return the number of
168 /// sign bits for the vector element with the mininum number of known sign
170 unsigned ComputeNumSignBits(const Value *Op, const DataLayout &DL,
171 unsigned Depth = 0, AssumptionCache *AC = nullptr,
172 const Instruction *CxtI = nullptr,
173 const DominatorTree *DT = nullptr,
174 bool UseInstrInfo = true);
176 /// This function computes the integer multiple of Base that equals V. If
177 /// successful, it returns true and returns the multiple in Multiple. If
178 /// unsuccessful, it returns false. Also, if V can be simplified to an
179 /// integer, then the simplified V is returned in Val. Look through sext only
180 /// if LookThroughSExt=true.
181 bool ComputeMultiple(Value *V, unsigned Base, Value *&Multiple,
182 bool LookThroughSExt = false,
185 /// Map a call instruction to an intrinsic ID. Libcalls which have equivalent
186 /// intrinsics are treated as-if they were intrinsics.
187 Intrinsic::ID getIntrinsicForCallSite(ImmutableCallSite ICS,
188 const TargetLibraryInfo *TLI);
190 /// Return true if we can prove that the specified FP value is never equal to
192 bool CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI,
195 /// Return true if we can prove that the specified FP value is either NaN or
196 /// never less than -0.0.
203 bool CannotBeOrderedLessThanZero(const Value *V, const TargetLibraryInfo *TLI);
205 /// Return true if the floating-point scalar value is not a NaN or if the
206 /// floating-point vector value has no NaN elements. Return false if a value
207 /// could ever be NaN.
208 bool isKnownNeverNaN(const Value *V, const TargetLibraryInfo *TLI,
211 /// Return true if we can prove that the specified FP value's sign bit is 0.
213 /// NaN --> true/false (depending on the NaN's sign bit)
218 bool SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI);
220 /// If the specified value can be set by repeating the same byte in memory,
221 /// return the i8 value that it is represented with. This is true for all i8
222 /// values obviously, but is also true for i32 0, i32 -1, i16 0xF0F0, double
223 /// 0.0 etc. If the value can't be handled with a repeated byte store (e.g.
224 /// i16 0x1234), return null. If the value is entirely undef and padding,
226 Value *isBytewiseValue(Value *V);
228 /// Given an aggregrate and an sequence of indices, see if the scalar value
229 /// indexed is already around as a register, for example if it were inserted
230 /// directly into the aggregrate.
232 /// If InsertBefore is not null, this function will duplicate (modified)
233 /// insertvalues when a part of a nested struct is extracted.
234 Value *FindInsertedValue(Value *V,
235 ArrayRef<unsigned> idx_range,
236 Instruction *InsertBefore = nullptr);
238 /// Analyze the specified pointer to see if it can be expressed as a base
239 /// pointer plus a constant offset. Return the base and offset to the caller.
240 Value *GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
241 const DataLayout &DL);
242 inline const Value *GetPointerBaseWithConstantOffset(const Value *Ptr,
244 const DataLayout &DL) {
245 return GetPointerBaseWithConstantOffset(const_cast<Value *>(Ptr), Offset,
249 /// Returns true if the GEP is based on a pointer to a string (array of
250 // \p CharSize integers) and is indexing into this string.
251 bool isGEPBasedOnPointerToString(const GEPOperator *GEP,
252 unsigned CharSize = 8);
254 /// Represents offset+length into a ConstantDataArray.
255 struct ConstantDataArraySlice {
256 /// ConstantDataArray pointer. nullptr indicates a zeroinitializer (a valid
257 /// initializer, it just doesn't fit the ConstantDataArray interface).
258 const ConstantDataArray *Array;
260 /// Slice starts at this Offset.
263 /// Length of the slice.
266 /// Moves the Offset and adjusts Length accordingly.
267 void move(uint64_t Delta) {
268 assert(Delta < Length);
273 /// Convenience accessor for elements in the slice.
274 uint64_t operator[](unsigned I) const {
275 return Array==nullptr ? 0 : Array->getElementAsInteger(I + Offset);
279 /// Returns true if the value \p V is a pointer into a ConstantDataArray.
280 /// If successful \p Slice will point to a ConstantDataArray info object
281 /// with an appropriate offset.
282 bool getConstantDataArrayInfo(const Value *V, ConstantDataArraySlice &Slice,
283 unsigned ElementSize, uint64_t Offset = 0);
285 /// This function computes the length of a null-terminated C string pointed to
286 /// by V. If successful, it returns true and returns the string in Str. If
287 /// unsuccessful, it returns false. This does not include the trailing null
288 /// character by default. If TrimAtNul is set to false, then this returns any
289 /// trailing null characters as well as any other characters that come after
291 bool getConstantStringInfo(const Value *V, StringRef &Str,
292 uint64_t Offset = 0, bool TrimAtNul = true);
294 /// If we can compute the length of the string pointed to by the specified
295 /// pointer, return 'len+1'. If we can't, return 0.
296 uint64_t GetStringLength(const Value *V, unsigned CharSize = 8);
298 /// This function returns call pointer argument that is considered the same by
299 /// aliasing rules. You CAN'T use it to replace one value with another.
300 const Value *getArgumentAliasingToReturnedPointer(const CallBase *Call);
301 inline Value *getArgumentAliasingToReturnedPointer(CallBase *Call) {
302 return const_cast<Value *>(getArgumentAliasingToReturnedPointer(
303 const_cast<const CallBase *>(Call)));
306 // {launder,strip}.invariant.group returns pointer that aliases its argument,
307 // and it only captures pointer by returning it.
308 // These intrinsics are not marked as nocapture, because returning is
309 // considered as capture. The arguments are not marked as returned neither,
310 // because it would make it useless.
311 bool isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
312 const CallBase *Call);
314 /// This method strips off any GEP address adjustments and pointer casts from
315 /// the specified value, returning the original object being addressed. Note
316 /// that the returned value has pointer type if the specified value does. If
317 /// the MaxLookup value is non-zero, it limits the number of instructions to
319 Value *GetUnderlyingObject(Value *V, const DataLayout &DL,
320 unsigned MaxLookup = 6);
321 inline const Value *GetUnderlyingObject(const Value *V, const DataLayout &DL,
322 unsigned MaxLookup = 6) {
323 return GetUnderlyingObject(const_cast<Value *>(V), DL, MaxLookup);
326 /// This method is similar to GetUnderlyingObject except that it can
327 /// look through phi and select instructions and return multiple objects.
329 /// If LoopInfo is passed, loop phis are further analyzed. If a pointer
330 /// accesses different objects in each iteration, we don't look through the
331 /// phi node. E.g. consider this loop nest:
336 /// A[i][j] = A[i-1][j] * B[j]
339 /// This is transformed by Load-PRE to stash away A[i] for the next iteration
340 /// of the outer loop:
342 /// Curr = A[0]; // Prev_0
344 /// Prev = Curr; // Prev = PHI (Prev_0, Curr)
347 /// Curr[j] = Prev[j] * B[j]
351 /// Since A[i] and A[i-1] are independent pointers, getUnderlyingObjects
352 /// should not assume that Curr and Prev share the same underlying object thus
353 /// it shouldn't look through the phi above.
354 void GetUnderlyingObjects(Value *V, SmallVectorImpl<Value *> &Objects,
355 const DataLayout &DL, LoopInfo *LI = nullptr,
356 unsigned MaxLookup = 6);
358 /// This is a wrapper around GetUnderlyingObjects and adds support for basic
359 /// ptrtoint+arithmetic+inttoptr sequences.
360 bool getUnderlyingObjectsForCodeGen(const Value *V,
361 SmallVectorImpl<Value *> &Objects,
362 const DataLayout &DL);
364 /// Return true if the only users of this pointer are lifetime markers.
365 bool onlyUsedByLifetimeMarkers(const Value *V);
367 /// Return true if the instruction does not have any effects besides
368 /// calculating the result and does not have undefined behavior.
370 /// This method never returns true for an instruction that returns true for
371 /// mayHaveSideEffects; however, this method also does some other checks in
372 /// addition. It checks for undefined behavior, like dividing by zero or
373 /// loading from an invalid pointer (but not for undefined results, like a
374 /// shift with a shift amount larger than the width of the result). It checks
375 /// for malloc and alloca because speculatively executing them might cause a
376 /// memory leak. It also returns false for instructions related to control
377 /// flow, specifically terminators and PHI nodes.
379 /// If the CtxI is specified this method performs context-sensitive analysis
380 /// and returns true if it is safe to execute the instruction immediately
383 /// If the CtxI is NOT specified this method only looks at the instruction
384 /// itself and its operands, so if this method returns true, it is safe to
385 /// move the instruction as long as the correct dominance relationships for
386 /// the operands and users hold.
388 /// This method can return true for instructions that read memory;
389 /// for such instructions, moving them may change the resulting value.
390 bool isSafeToSpeculativelyExecute(const Value *V,
391 const Instruction *CtxI = nullptr,
392 const DominatorTree *DT = nullptr);
394 /// Returns true if the result or effects of the given instructions \p I
395 /// depend on or influence global memory.
396 /// Memory dependence arises for example if the instruction reads from
397 /// memory or may produce effects or undefined behaviour. Memory dependent
398 /// instructions generally cannot be reorderd with respect to other memory
399 /// dependent instructions or moved into non-dominated basic blocks.
400 /// Instructions which just compute a value based on the values of their
401 /// operands are not memory dependent.
402 bool mayBeMemoryDependent(const Instruction &I);
404 /// Return true if it is an intrinsic that cannot be speculated but also
406 bool isAssumeLikeIntrinsic(const Instruction *I);
408 /// Return true if it is valid to use the assumptions provided by an
409 /// assume intrinsic, I, at the point in the control-flow identified by the
410 /// context instruction, CxtI.
411 bool isValidAssumeForContext(const Instruction *I, const Instruction *CxtI,
412 const DominatorTree *DT = nullptr);
414 enum class OverflowResult { AlwaysOverflows, MayOverflow, NeverOverflows };
416 OverflowResult computeOverflowForUnsignedMul(const Value *LHS,
418 const DataLayout &DL,
420 const Instruction *CxtI,
421 const DominatorTree *DT,
422 bool UseInstrInfo = true);
423 OverflowResult computeOverflowForSignedMul(const Value *LHS, const Value *RHS,
424 const DataLayout &DL,
426 const Instruction *CxtI,
427 const DominatorTree *DT,
428 bool UseInstrInfo = true);
429 OverflowResult computeOverflowForUnsignedAdd(const Value *LHS,
431 const DataLayout &DL,
433 const Instruction *CxtI,
434 const DominatorTree *DT,
435 bool UseInstrInfo = true);
436 OverflowResult computeOverflowForSignedAdd(const Value *LHS, const Value *RHS,
437 const DataLayout &DL,
438 AssumptionCache *AC = nullptr,
439 const Instruction *CxtI = nullptr,
440 const DominatorTree *DT = nullptr);
441 /// This version also leverages the sign bit of Add if known.
442 OverflowResult computeOverflowForSignedAdd(const AddOperator *Add,
443 const DataLayout &DL,
444 AssumptionCache *AC = nullptr,
445 const Instruction *CxtI = nullptr,
446 const DominatorTree *DT = nullptr);
447 OverflowResult computeOverflowForUnsignedSub(const Value *LHS, const Value *RHS,
448 const DataLayout &DL,
450 const Instruction *CxtI,
451 const DominatorTree *DT);
452 OverflowResult computeOverflowForSignedSub(const Value *LHS, const Value *RHS,
453 const DataLayout &DL,
455 const Instruction *CxtI,
456 const DominatorTree *DT);
458 /// Returns true if the arithmetic part of the \p II 's result is
459 /// used only along the paths control dependent on the computation
460 /// not overflowing, \p II being an <op>.with.overflow intrinsic.
461 bool isOverflowIntrinsicNoWrap(const IntrinsicInst *II,
462 const DominatorTree &DT);
464 /// Return true if this function can prove that the instruction I will
465 /// always transfer execution to one of its successors (including the next
466 /// instruction that follows within a basic block). E.g. this is not
467 /// guaranteed for function calls that could loop infinitely.
469 /// In other words, this function returns false for instructions that may
470 /// transfer execution or fail to transfer execution in a way that is not
471 /// captured in the CFG nor in the sequence of instructions within a basic
474 /// Undefined behavior is assumed not to happen, so e.g. division is
475 /// guaranteed to transfer execution to the following instruction even
476 /// though division by zero might cause undefined behavior.
477 bool isGuaranteedToTransferExecutionToSuccessor(const Instruction *I);
479 /// Returns true if this block does not contain a potential implicit exit.
480 /// This is equivelent to saying that all instructions within the basic block
481 /// are guaranteed to transfer execution to their successor within the basic
482 /// block. This has the same assumptions w.r.t. undefined behavior as the
483 /// instruction variant of this function.
484 bool isGuaranteedToTransferExecutionToSuccessor(const BasicBlock *BB);
486 /// Return true if this function can prove that the instruction I
487 /// is executed for every iteration of the loop L.
489 /// Note that this currently only considers the loop header.
490 bool isGuaranteedToExecuteForEveryIteration(const Instruction *I,
493 /// Return true if this function can prove that I is guaranteed to yield
494 /// full-poison (all bits poison) if at least one of its operands are
495 /// full-poison (all bits poison).
497 /// The exact rules for how poison propagates through instructions have
498 /// not been settled as of 2015-07-10, so this function is conservative
499 /// and only considers poison to be propagated in uncontroversial
500 /// cases. There is no attempt to track values that may be only partially
502 bool propagatesFullPoison(const Instruction *I);
504 /// Return either nullptr or an operand of I such that I will trigger
505 /// undefined behavior if I is executed and that operand has a full-poison
506 /// value (all bits poison).
507 const Value *getGuaranteedNonFullPoisonOp(const Instruction *I);
509 /// Return true if this function can prove that if PoisonI is executed
510 /// and yields a full-poison value (all bits poison), then that will
511 /// trigger undefined behavior.
513 /// Note that this currently only considers the basic block that is
515 bool programUndefinedIfFullPoison(const Instruction *PoisonI);
517 /// Specific patterns of select instructions we can match.
518 enum SelectPatternFlavor {
520 SPF_SMIN, /// Signed minimum
521 SPF_UMIN, /// Unsigned minimum
522 SPF_SMAX, /// Signed maximum
523 SPF_UMAX, /// Unsigned maximum
524 SPF_FMINNUM, /// Floating point minnum
525 SPF_FMAXNUM, /// Floating point maxnum
526 SPF_ABS, /// Absolute value
527 SPF_NABS /// Negated absolute value
530 /// Behavior when a floating point min/max is given one NaN and one
531 /// non-NaN as input.
532 enum SelectPatternNaNBehavior {
533 SPNB_NA = 0, /// NaN behavior not applicable.
534 SPNB_RETURNS_NAN, /// Given one NaN input, returns the NaN.
535 SPNB_RETURNS_OTHER, /// Given one NaN input, returns the non-NaN.
536 SPNB_RETURNS_ANY /// Given one NaN input, can return either (or
537 /// it has been determined that no operands can
541 struct SelectPatternResult {
542 SelectPatternFlavor Flavor;
543 SelectPatternNaNBehavior NaNBehavior; /// Only applicable if Flavor is
544 /// SPF_FMINNUM or SPF_FMAXNUM.
545 bool Ordered; /// When implementing this min/max pattern as
546 /// fcmp; select, does the fcmp have to be
549 /// Return true if \p SPF is a min or a max pattern.
550 static bool isMinOrMax(SelectPatternFlavor SPF) {
551 return SPF != SPF_UNKNOWN && SPF != SPF_ABS && SPF != SPF_NABS;
555 /// Pattern match integer [SU]MIN, [SU]MAX and ABS idioms, returning the kind
556 /// and providing the out parameter results if we successfully match.
558 /// For ABS/NABS, LHS will be set to the input to the abs idiom. RHS will be
559 /// the negation instruction from the idiom.
561 /// If CastOp is not nullptr, also match MIN/MAX idioms where the type does
562 /// not match that of the original select. If this is the case, the cast
563 /// operation (one of Trunc,SExt,Zext) that must be done to transform the
564 /// type of LHS and RHS into the type of V is returned in CastOp.
567 /// %1 = icmp slt i32 %a, i32 4
568 /// %2 = sext i32 %a to i64
569 /// %3 = select i1 %1, i64 %2, i64 4
571 /// -> LHS = %a, RHS = i32 4, *CastOp = Instruction::SExt
573 SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS,
574 Instruction::CastOps *CastOp = nullptr,
576 inline SelectPatternResult
577 matchSelectPattern(const Value *V, const Value *&LHS, const Value *&RHS,
578 Instruction::CastOps *CastOp = nullptr) {
579 Value *L = const_cast<Value*>(LHS);
580 Value *R = const_cast<Value*>(RHS);
581 auto Result = matchSelectPattern(const_cast<Value*>(V), L, R);
587 /// Return the canonical comparison predicate for the specified
588 /// minimum/maximum flavor.
589 CmpInst::Predicate getMinMaxPred(SelectPatternFlavor SPF,
590 bool Ordered = false);
592 /// Return the inverse minimum/maximum flavor of the specified flavor.
593 /// For example, signed minimum is the inverse of signed maximum.
594 SelectPatternFlavor getInverseMinMaxFlavor(SelectPatternFlavor SPF);
596 /// Return the canonical inverse comparison predicate for the specified
597 /// minimum/maximum flavor.
598 CmpInst::Predicate getInverseMinMaxPred(SelectPatternFlavor SPF);
600 /// Return true if RHS is known to be implied true by LHS. Return false if
601 /// RHS is known to be implied false by LHS. Otherwise, return None if no
602 /// implication can be made.
603 /// A & B must be i1 (boolean) values or a vector of such values. Note that
604 /// the truth table for implication is the same as <=u on i1 values (but not
605 /// <=s!). The truth table for both is:
610 Optional<bool> isImpliedCondition(const Value *LHS, const Value *RHS,
611 const DataLayout &DL, bool LHSIsTrue = true,
614 /// Return the boolean condition value in the context of the given instruction
615 /// if it is known based on dominating conditions.
616 Optional<bool> isImpliedByDomCondition(const Value *Cond,
617 const Instruction *ContextI,
618 const DataLayout &DL);
619 } // end namespace llvm
621 #endif // LLVM_ANALYSIS_VALUETRACKING_H