[llvm] Remove redundant initialization of std::optional (NFC)

Author: kazutakahirata

llvm/include/llvm/Analysis/InlineCost.h

@@ -102,7 +102,7 @@ class InlineCost {
   const char *Reason = nullptr;
 
   /// The cost-benefit pair computed by cost-benefit analysis.
-  std::optional<CostBenefitPair> CostBenefit = std::nullopt;
+  std::optional<CostBenefitPair> CostBenefit;
 
   // Trivial constructor, interesting logic in the factory functions below.
   InlineCost(int Cost, int Threshold, int StaticBonusApplied,

llvm/include/llvm/DWP/DWP.h

@@ -44,7 +44,7 @@ struct InfoSectionUnitHeader {
 
   // dwo_id field. This resides in the header only if Version >= 5.
   // In earlier versions, it is read from DW_AT_GNU_dwo_id.
-  std::optional<uint64_t> Signature = std::nullopt;
+  std::optional<uint64_t> Signature;
 
   // Derived from the length of Length field.
   dwarf::DwarfFormat Format = dwarf::DwarfFormat::DWARF32;

llvm/include/llvm/IR/Instructions.h

@@ -3612,7 +3612,7 @@ class SwitchInst : public Instruction {
 /// their prof branch_weights metadata.
 class SwitchInstProfUpdateWrapper {
   SwitchInst &SI;
-  std::optional<SmallVector<uint32_t, 8>> Weights = std::nullopt;
+  std::optional<SmallVector<uint32_t, 8>> Weights;
   bool Changed = false;
 
 protected:

llvm/include/llvm/LTO/Config.h

@@ -53,7 +53,7 @@ struct Config {
   /// For adding passes that run right before codegen.
   std::function<void(legacy::PassManager &)> PreCodeGenPassesHook;
   std::optional<Reloc::Model> RelocModel = Reloc::PIC_;
-  std::optional<CodeModel::Model> CodeModel = std::nullopt;
+  std::optional<CodeModel::Model> CodeModel;
   CodeGenOpt::Level CGOptLevel = CodeGenOpt::Default;
   CodeGenFileType CGFileType = CGFT_ObjectFile;
   unsigned OptLevel = 2;

llvm/include/llvm/Object/ELF.h

@@ -120,7 +120,7 @@ template <class T> struct DataRegion {
   }
 
   const T *First;
-  std::optional<uint64_t> Size = std::nullopt;
+  std::optional<uint64_t> Size;
   const uint8_t *BufEnd = nullptr;
 };
 

llvm/include/llvm/Target/TargetMachine.h

@@ -110,7 +110,7 @@ class TargetMachine {
   unsigned O0WantsFastISel : 1;
 
   // PGO related tunables.
-  std::optional<PGOOptions> PGOOption = std::nullopt;
+  std::optional<PGOOptions> PGOOption;
 
 public:
   const TargetOptions DefaultOptions;

llvm/include/llvm/Transforms/IPO/Attributor.h

@@ -1385,7 +1385,7 @@ struct AttributorConfig {
   DenseSet<const char *> *Allowed = nullptr;
 
   /// Maximum number of iterations to run until fixpoint.
-  std::optional<unsigned> MaxFixpointIterations = std::nullopt;
+  std::optional<unsigned> MaxFixpointIterations;
 
   /// A callback function that returns an ORE object from a Function pointer.
   ///{

llvm/include/llvm/Transforms/Scalar/GVN.h

@@ -72,11 +72,11 @@ class GVNLegacyPass;
 /// Intended use is to create a default object, modify parameters with
 /// additional setters and then pass it to GVN.
 struct GVNOptions {
-  std::optional<bool> AllowPRE = std::nullopt;
-  std::optional<bool> AllowLoadPRE = std::nullopt;
-  std::optional<bool> AllowLoadInLoopPRE = std::nullopt;
-  std::optional<bool> AllowLoadPRESplitBackedge = std::nullopt;
-  std::optional<bool> AllowMemDep = std::nullopt;
+  std::optional<bool> AllowPRE;
+  std::optional<bool> AllowLoadPRE;
+  std::optional<bool> AllowLoadInLoopPRE;
+  std::optional<bool> AllowLoadPRESplitBackedge;
+  std::optional<bool> AllowMemDep;
 
   GVNOptions() = default;
 

llvm/lib/Analysis/InlineCost.cpp

@@ -584,7 +584,7 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
   bool DecidedByCostBenefit = false;
 
   // The cost-benefit pair computed by cost-benefit analysis.
-  std::optional<CostBenefitPair> CostBenefit = std::nullopt;
+  std::optional<CostBenefitPair> CostBenefit;
 
   bool SingleBB = true;
 

llvm/lib/Analysis/MemorySSA.cpp

@@ -719,7 +719,7 @@ class ClobberWalker {
     T &curNode() const { return W->Paths[*N]; }
 
     Walker *W = nullptr;
-    std::optional<ListIndex> N = std::nullopt;
+    std::optional<ListIndex> N;
   };
 
   using def_path_iterator = generic_def_path_iterator<DefPath, ClobberWalker>;