[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

15 files changed, 49 insertions, 47 deletions

diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
index 74e5631..b65eceb 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
@@ -1543,10 +1543,10 @@ bool InstrRefBasedLDV::transferDebugInstrRef(MachineInstr &MI,
     }
   }
 
-  // We, we have a value number or None. Tell the variable value tracker about
-  // it. The rest of this LiveDebugValues implementation acts exactly the same
-  // for DBG_INSTR_REFs as DBG_VALUEs (just, the former can refer to values that
-  // aren't immediately available).
+  // We, we have a value number or std::nullopt. Tell the variable value tracker
+  // about it. The rest of this LiveDebugValues implementation acts exactly the
+  // same for DBG_INSTR_REFs as DBG_VALUEs (just, the former can refer to values
+  // that aren't immediately available).
   DbgValueProperties Properties(Expr, false, false);
   SmallVector<DbgOpID> DbgOpIDs;
   if (NewID)
diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h
index 27438da..9d0f4d0 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h
+++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h
@@ -1127,11 +1127,11 @@ private:
     uint64_t InstrNum;
     /// Block where DBG_PHI occurred.
     MachineBasicBlock *MBB;
-    /// The value number read by the DBG_PHI -- or None if it didn't refer to
-    /// a value.
+    /// The value number read by the DBG_PHI -- or std::nullopt if it didn't
+    /// refer to a value.
     Optional<ValueIDNum> ValueRead;
-    /// Register/Stack location the DBG_PHI reads -- or None if it referred to
-    /// something unexpected.
+    /// Register/Stack location the DBG_PHI reads -- or std::nullopt if it
+    /// referred to something unexpected.
     Optional<LocIdx> ReadLoc;
 
     operator unsigned() const { return InstrNum; }
@@ -1229,7 +1229,7 @@ private:
   /// forming another mini-ssa problem to solve.
   /// \p Here the position of a DBG_INSTR_REF seeking a machine value number
   /// \p InstrNum Debug instruction number defined by DBG_PHI instructions.
-  /// \returns The machine value number at position Here, or None.
+  /// \returns The machine value number at position Here, or std::nullopt.
   Optional<ValueIDNum> resolveDbgPHIs(MachineFunction &MF,
                                       const ValueTable *MLiveOuts,
                                       const ValueTable *MLiveIns,
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
index 5e56330..5487667 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -716,7 +716,7 @@ DWARFDebugLine::ParsingState::handleSpecialOpcode(uint8_t Opcode,
 }
 
 /// Parse a ULEB128 using the specified \p Cursor. \returns the parsed value on
-/// success, or None if \p Cursor is in a failing state.
+/// success, or std::nullopt if \p Cursor is in a failing state.
 template <typename T>
 static std::optional<T> parseULEB128(DWARFDataExtractor &Data,
                                      DataExtractor::Cursor &Cursor) {
diff --git a/llvm/lib/DebugInfo/Symbolize/Markup.cpp b/llvm/lib/DebugInfo/Symbolize/Markup.cpp
index ae3e24c0..a8e74af 100644
--- a/llvm/lib/DebugInfo/Symbolize/Markup.cpp
+++ b/llvm/lib/DebugInfo/Symbolize/Markup.cpp
@@ -110,7 +110,7 @@ void MarkupParser::flush() {
 }
 
 // Finds and returns the next valid markup element in the given line. Returns
-// None if the line contains no valid elements.
+// std::nullopt if the line contains no valid elements.
 std::optional<MarkupNode> MarkupParser::parseElement(StringRef Line) {
   while (true) {
     // Find next element using begin and end markers.
diff --git a/llvm/lib/FileCheck/FileCheckImpl.h b/llvm/lib/FileCheck/FileCheckImpl.h
index ccfcda6..556be6b 100644
--- a/llvm/lib/FileCheck/FileCheckImpl.h
+++ b/llvm/lib/FileCheck/FileCheckImpl.h
@@ -265,16 +265,16 @@ private:
   /// format.
   ExpressionFormat ImplicitFormat;
 
-  /// Value of numeric variable, if defined, or None otherwise.
+  /// Value of numeric variable, if defined, or std::nullopt otherwise.
   Optional<ExpressionValue> Value;
 
-  /// The input buffer's string from which Value was parsed, or None.  See
-  /// comments on getStringValue for a discussion of the None case.
+  /// The input buffer's string from which Value was parsed, or std::nullopt.
+  /// See comments on getStringValue for a discussion of the None case.
   Optional<StringRef> StrValue;
 
-  /// Line number where this variable is defined, or None if defined before
-  /// input is parsed. Used to determine whether a variable is defined on the
-  /// same line as a given use.
+  /// Line number where this variable is defined, or std::nullopt if defined
+  /// before input is parsed. Used to determine whether a variable is defined on
+  /// the same line as a given use.
   Optional<size_t> DefLineNumber;
 
 public:
@@ -296,9 +296,9 @@ public:
   Optional<ExpressionValue> getValue() const { return Value; }
 
   /// \returns the input buffer's string from which this variable's value was
-  /// parsed, or None if the value is not yet defined or was not parsed from the
-  /// input buffer.  For example, the value of @LINE is not parsed from the
-  /// input buffer, and some numeric variables are parsed from the command
+  /// parsed, or std::nullopt if the value is not yet defined or was not parsed
+  /// from the input buffer.  For example, the value of @LINE is not parsed from
+  /// the input buffer, and some numeric variables are parsed from the command
   /// line instead.
   Optional<StringRef> getStringValue() const { return StrValue; }
 
@@ -318,8 +318,8 @@ public:
     StrValue = std::nullopt;
   }
 
-  /// \returns the line number where this variable is defined, if any, or None
-  /// if defined before input is parsed.
+  /// \returns the line number where this variable is defined, if any, or
+  /// std::nullopt if defined before input is parsed.
   Optional<size_t> getDefLineNumber() const { return DefLineNumber; }
 };
 
@@ -672,9 +672,9 @@ class Pattern {
 
   Check::FileCheckType CheckTy;
 
-  /// Line number for this CHECK pattern or None if it is an implicit pattern.
-  /// Used to determine whether a variable definition is made on an earlier
-  /// line to the one with this CHECK.
+  /// Line number for this CHECK pattern or std::nullopt if it is an implicit
+  /// pattern. Used to determine whether a variable definition is made on an
+  /// earlier line to the one with this CHECK.
   Optional<size_t> LineNumber;
 
   /// Ignore case while matching if set to true.
@@ -717,7 +717,7 @@ public:
   /// holding a diagnostic against \p SM if parsing fails. If substitution was
   /// successful, sets \p DefinedNumericVariable to point to the class
   /// representing the numeric variable defined in this numeric substitution
-  /// block, or None if this block does not define any variable.
+  /// block, or std::nullopt if this block does not define any variable.
   static Expected<std::unique_ptr<Expression>> parseNumericSubstitutionBlock(
       StringRef Expr, Optional<NumericVariable *> &DefinedNumericVariable,
       bool IsLegacyLineExpr, Optional<size_t> LineNumber,
diff --git a/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp b/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
index 51a2503..ac36650 100644
--- a/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
+++ b/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
@@ -689,7 +689,8 @@ static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
 }
 
 /// Check if SourceFile is the file that contains the definition of
-/// the Function. Return the ID of the file in that case or None otherwise.
+/// the Function. Return the ID of the file in that case or std::nullopt
+/// otherwise.
 static Optional<unsigned> findMainViewFileID(StringRef SourceFile,
                                              const FunctionRecord &Function) {
   Optional<unsigned> I = findMainViewFileID(Function);
diff --git a/llvm/lib/Target/AArch64/AArch64CompressJumpTables.cpp b/llvm/lib/Target/AArch64/AArch64CompressJumpTables.cpp
index 05919c8..75abe9c 100644
--- a/llvm/lib/Target/AArch64/AArch64CompressJumpTables.cpp
+++ b/llvm/lib/Target/AArch64/AArch64CompressJumpTables.cpp
@@ -37,8 +37,8 @@ class AArch64CompressJumpTables : public MachineFunctionPass {
   MachineFunction *MF;
   SmallVector<int, 8> BlockInfo;
 
-  /// Returns the size in instructions of the block \p MBB, or None if we
-  /// couldn't get a safe upper bound.
+  /// Returns the size in instructions of the block \p MBB, or std::nullopt if
+  /// we couldn't get a safe upper bound.
   std::optional<int> computeBlockSize(MachineBasicBlock &MBB);
 
   /// Gather information about the function, returns false if we can't perform
diff --git a/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h b/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h
index 24ec9b2..d7812b8 100644
--- a/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h
+++ b/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h
@@ -1237,7 +1237,7 @@ bool isLegalSMRDEncodedSignedOffset(const MCSubtargetInfo &ST,
 uint64_t convertSMRDOffsetUnits(const MCSubtargetInfo &ST, uint64_t ByteOffset);
 
 /// \returns The encoding that will be used for \p ByteOffset in the
-/// SMRD offset field, or None if it won't fit. On GFX9 and GFX10
+/// SMRD offset field, or std::nullopt if it won't fit. On GFX9 and GFX10
 /// S_LOAD instructions have a signed offset, on other subtargets it is
 /// unsigned. S_BUFFER has an unsigned offset for all subtargets.
 Optional<int64_t> getSMRDEncodedOffset(const MCSubtargetInfo &ST,
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFStreamer.cpp b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFStreamer.cpp
index 4428c4f..dfc0409 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFStreamer.cpp
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFStreamer.cpp
@@ -191,10 +191,10 @@ void PPCELFStreamer::emitGOTToPCRelLabel(const MCInst &Inst) {
 // <MCInst SOME_LOAD <MCOperand Reg:22> <MCOperand Imm:0> <MCOperand Reg:282>
 //   <MCOperand Expr:(.Lpcrel@<<invalid>>)>>
 // The above is a pair of such instructions and this function will not return
-// None for either one of them. In both cases we are looking for the last
-// operand <MCOperand Expr:(.Lpcrel@<<invalid>>)> which needs to be an MCExpr
-// and has the flag MCSymbolRefExpr::VK_PPC_PCREL_OPT. After that we just look
-// at the opcode and in the case of PLDpc we will return true. For the load
+// std::nullopt for either one of them. In both cases we are looking for the
+// last operand <MCOperand Expr:(.Lpcrel@<<invalid>>)> which needs to be an
+// MCExpr and has the flag MCSymbolRefExpr::VK_PPC_PCREL_OPT. After that we just
+// look at the opcode and in the case of PLDpc we will return true. For the load
 // (or store) this function will return false indicating it has found the second
 // instruciton in the pair.
 std::optional<bool> llvm::isPartOfGOTToPCRelPair(const MCInst &Inst,
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
index 13a05b0..528b33e 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
@@ -55,7 +55,7 @@ public:
                        const DebugLoc &DL) const;
 
   // Returns the index of the WebAssembly local to which the stack object
-  // FrameIndex in MF should be allocated, or None.
+  // FrameIndex in MF should be allocated, or std::nullopt.
   static std::optional<unsigned> getLocalForStackObject(MachineFunction &MF,
                                                         int FrameIndex);
 
diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index ebb5c47..820a454 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -1074,8 +1074,8 @@ Attributor::getAssumedConstant(const IRPosition &IRP,
                                const AbstractAttribute &AA,
                                bool &UsedAssumedInformation) {
   // First check all callbacks provided by outside AAs. If any of them returns
-  // a non-null value that is different from the associated value, or None, we
-  // assume it's simplified.
+  // a non-null value that is different from the associated value, or
+  // std::nullopt, we assume it's simplified.
   for (auto &CB : SimplificationCallbacks.lookup(IRP)) {
     Optional<Value *> SimplifiedV = CB(IRP, &AA, UsedAssumedInformation);
     if (!SimplifiedV)
@@ -1104,8 +1104,8 @@ Optional<Value *> Attributor::getAssumedSimplified(const IRPosition &IRP,
                                                    bool &UsedAssumedInformation,
                                                    AA::ValueScope S) {
   // First check all callbacks provided by outside AAs. If any of them returns
-  // a non-null value that is different from the associated value, or None, we
-  // assume it's simplified.
+  // a non-null value that is different from the associated value, or
+  // std::nullopt, we assume it's simplified.
   for (auto &CB : SimplificationCallbacks.lookup(IRP))
     return CB(IRP, AA, UsedAssumedInformation);
 
@@ -1128,8 +1128,8 @@ bool Attributor::getAssumedSimplifiedValues(
     SmallVectorImpl<AA::ValueAndContext> &Values, AA::ValueScope S,
     bool &UsedAssumedInformation) {
   // First check all callbacks provided by outside AAs. If any of them returns
-  // a non-null value that is different from the associated value, or None, we
-  // assume it's simplified.
+  // a non-null value that is different from the associated value, or
+  // std::nullopt, we assume it's simplified.
   const auto &SimplificationCBs = SimplificationCallbacks.lookup(IRP);
   for (const auto &CB : SimplificationCBs) {
     Optional<Value *> CBResult = CB(IRP, AA, UsedAssumedInformation);
diff --git a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
index 4ce9611..cc667e5 100644
--- a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -9617,7 +9617,7 @@ private:
       Unreachable.erase(&Fn);
     }
 
-    /// If there is no information about the function None is returned.
+    /// If there is no information about the function std::nullopt is returned.
     Optional<bool> isCachedReachable(const Function &Fn) {
       // Assume that we can reach the function.
       // TODO: Be more specific with the unknown callee.
diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
index d4ff9f68..afa46f2 100644
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -1171,8 +1171,8 @@ static hash_code encodePHINodeData(PHINodeData &PND) {
 /// \param PN - The PHINode we are analyzing.
 /// \param Blocks - The blocks for the region we are analyzing.
 /// \param AggArgIdx - The argument \p PN will be stored into.
-/// \returns An optional holding the assigned canonical number, or None if
-/// there is some attribute of the PHINode blocking it from being used.
+/// \returns An optional holding the assigned canonical number, or std::nullopt
+/// if there is some attribute of the PHINode blocking it from being used.
 static Optional<unsigned> getGVNForPHINode(OutlinableRegion &Region,
                                            PHINode *PN,
                                            DenseSet<BasicBlock *> &Blocks,
diff --git a/llvm/lib/Transforms/Scalar/Scalarizer.cpp b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
index 0316a14..3cab256 100644
--- a/llvm/lib/Transforms/Scalar/Scalarizer.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
@@ -481,7 +481,8 @@ void ScalarizerVisitor::transferMetadataAndIRFlags(Instruction *Op,
 }
 
 // Try to fill in Layout from Ty, returning true on success.  Alignment is
-// the alignment of the vector, or None if the ABI default should be used.
+// the alignment of the vector, or std::nullopt if the ABI default should be
+// used.
 Optional<VectorLayout>
 ScalarizerVisitor::getVectorLayout(Type *Ty, Align Alignment,
                                    const DataLayout &DL) {
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h b/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
index 7c73079..4c635579 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
@@ -295,8 +295,8 @@ public:
       : OrigLoop(L), LI(LI), TLI(TLI), TTI(TTI), Legal(Legal), CM(CM), IAI(IAI),
         PSE(PSE), Hints(Hints), ORE(ORE) {}
 
-  /// Plan how to best vectorize, return the best VF and its cost, or None if
-  /// vectorization and interleaving should be avoided up front.
+  /// Plan how to best vectorize, return the best VF and its cost, or
+  /// std::nullopt if vectorization and interleaving should be avoided up front.
   Optional<VectorizationFactor> plan(ElementCount UserVF, unsigned UserIC);
 
   /// Use the VPlan-native path to plan how to best vectorize, return the best