[llvm] Use std::nullopt instead of None in comments (NFC)

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

1 files changed, 9 insertions, 8 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 878177e..2459429 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -2742,7 +2742,7 @@ bool isKnownNonZero(const Value* V, unsigned Depth, const Query& Q) {
 
 /// If the pair of operators are the same invertible function, return the
 /// the operands of the function corresponding to each input. Otherwise,
-/// return None.  An invertible function is one that is 1-to-1 and maps
+/// return std::nullopt.  An invertible function is one that is 1-to-1 and maps
 /// every input value to exactly one output value.  This is equivalent to
 /// saying that Op1 and Op2 are equal exactly when the specified pair of
 /// operands are equal, (except that Op1 and Op2 may be poison more often.)
@@ -6657,7 +6657,7 @@ static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
 }
 
 /// Return true if "icmp Pred BLHS BRHS" is true whenever "icmp Pred
-/// ALHS ARHS" is true.  Otherwise, return None.
+/// ALHS ARHS" is true.  Otherwise, return std::nullopt.
 static Optional<bool>
 isImpliedCondOperands(CmpInst::Predicate Pred, const Value *ALHS,
                       const Value *ARHS, const Value *BLHS, const Value *BRHS,
@@ -6694,7 +6694,7 @@ static bool areMatchingOperands(const Value *L0, const Value *L1, const Value *R
 
 /// Return true if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is true.
 /// Return false if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is false.
-/// Otherwise, return None if we can't infer anything.
+/// Otherwise, return std::nullopt if we can't infer anything.
 static Optional<bool> isImpliedCondMatchingOperands(CmpInst::Predicate LPred,
                                                     CmpInst::Predicate RPred,
                                                     bool AreSwappedOps) {
@@ -6712,7 +6712,7 @@ static Optional<bool> isImpliedCondMatchingOperands(CmpInst::Predicate LPred,
 
 /// Return true if "icmp LPred X, LC" implies "icmp RPred X, RC" is true.
 /// Return false if "icmp LPred X, LC" implies "icmp RPred X, RC" is false.
-/// Otherwise, return None if we can't infer anything.
+/// Otherwise, return std::nullopt if we can't infer anything.
 static Optional<bool> isImpliedCondCommonOperandWithConstants(
     CmpInst::Predicate LPred, const APInt &LC, CmpInst::Predicate RPred,
     const APInt &RC) {
@@ -6728,8 +6728,8 @@ static Optional<bool> isImpliedCondCommonOperandWithConstants(
 }
 
 /// Return true if LHS implies RHS (expanded to its components as "R0 RPred R1")
-/// is true.  Return false if LHS implies RHS is false. Otherwise, return None
-/// if we can't infer anything.
+/// is true.  Return false if LHS implies RHS is false. Otherwise, return
+/// std::nullopt if we can't infer anything.
 static Optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
                                          CmpInst::Predicate RPred,
                                          const Value *R0, const Value *R1,
@@ -6761,8 +6761,9 @@ static Optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
 }
 
 /// Return true if LHS implies RHS is true.  Return false if LHS implies RHS is
-/// false.  Otherwise, return None if we can't infer anything.  We expect the
-/// RHS to be an icmp and the LHS to be an 'and', 'or', or a 'select' instruction.
+/// false.  Otherwise, return std::nullopt if we can't infer anything.  We
+/// expect the RHS to be an icmp and the LHS to be an 'and', 'or', or a 'select'
+/// instruction.
 static Optional<bool>
 isImpliedCondAndOr(const Instruction *LHS, CmpInst::Predicate RHSPred,
                    const Value *RHSOp0, const Value *RHSOp1,