[polly] Use std::optional instead of llvm::Optional (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

polly/include/polly/ScopInfo.h

@@ -34,6 +34,7 @@
 #include <cassert>
 #include <cstddef>
 #include <forward_list>
+#include <optional>
 
 namespace polly {
 using llvm::AnalysisInfoMixin;
@@ -51,7 +52,6 @@ using llvm::LoadInst;
 using llvm::make_range;
 using llvm::MapVector;
 using llvm::MemIntrinsic;
-using llvm::Optional;
 using llvm::PassInfoMixin;
 using llvm::PHINode;
 using llvm::RegionNode;
@@ -1662,7 +1662,7 @@ private:
   Region &R;
 
   /// The name of the SCoP (identical to the regions name)
-  Optional<std::string> name;
+  std::optional<std::string> name;
 
   // Access functions of the SCoP.
   //

polly/include/polly/Support/ScopHelper.h

@@ -18,6 +18,7 @@
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/ValueHandle.h"
 #include "isl/isl-noexceptions.h"
+#include <optional>
 
 namespace llvm {
 class LoopInfo;
@@ -522,16 +523,16 @@ bool hasDebugCall(ScopStmt *Stmt);
 ///
 /// Then `nullptr` is set to mark the property is existing, but does not carry
 /// any value. If the property does not exist, `None` is returned.
-llvm::Optional<llvm::Metadata *> findMetadataOperand(llvm::MDNode *LoopMD,
-                                                     llvm::StringRef Name);
+std::optional<llvm::Metadata *> findMetadataOperand(llvm::MDNode *LoopMD,
+                                                    llvm::StringRef Name);
 
 /// Find a boolean property value in a LoopID. The value not being defined is
 /// interpreted as a false value.
 bool getBooleanLoopAttribute(llvm::MDNode *LoopID, llvm::StringRef Name);
 
 /// Find an integers property value in a LoopID.
-llvm::Optional<int> getOptionalIntLoopAttribute(llvm::MDNode *LoopID,
-                                                llvm::StringRef Name);
+std::optional<int> getOptionalIntLoopAttribute(llvm::MDNode *LoopID,
+                                               llvm::StringRef Name);
 
 /// Does the loop's LoopID contain a 'llvm.loop.disable_heuristics' property?
 ///

polly/lib/Analysis/ScopPass.cpp

@@ -19,6 +19,7 @@
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include <optional>
 
 using namespace llvm;
 using namespace polly;
@@ -119,7 +120,7 @@ bool ScopAnalysisManagerFunctionProxy::Result::invalidate(
   // Even if all analyses were preserved, we still need to run deferred
   // invalidation
   for (auto &S : *SI) {
-    Optional<PreservedAnalyses> InnerPA;
+    std::optional<PreservedAnalyses> InnerPA;
     auto *scop = S.second.get();
     if (!scop)
       continue;

polly/lib/Support/ScopHelper.cpp

@@ -21,6 +21,7 @@
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/LoopUtils.h"
 #include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
+#include <optional>
 
 using namespace llvm;
 using namespace polly;
@@ -699,8 +700,8 @@ static MDNode *findNamedMetadataNode(MDNode *LoopMD, StringRef Name) {
   return nullptr;
 }
 
-static Optional<const MDOperand *> findNamedMetadataArg(MDNode *LoopID,
-                                                        StringRef Name) {
+static std::optional<const MDOperand *> findNamedMetadataArg(MDNode *LoopID,
+                                                             StringRef Name) {
   MDNode *MD = findNamedMetadataNode(LoopID, Name);
   if (!MD)
     return std::nullopt;
@@ -714,8 +715,8 @@ static Optional<const MDOperand *> findNamedMetadataArg(MDNode *LoopID,
   }
 }
 
-Optional<Metadata *> polly::findMetadataOperand(MDNode *LoopMD,
-                                                StringRef Name) {
+std::optional<Metadata *> polly::findMetadataOperand(MDNode *LoopMD,
+                                                     StringRef Name) {
   MDNode *MD = findNamedMetadataNode(LoopMD, Name);
   if (!MD)
     return std::nullopt;
@@ -729,8 +730,8 @@ Optional<Metadata *> polly::findMetadataOperand(MDNode *LoopMD,
   }
 }
 
-static Optional<bool> getOptionalBoolLoopAttribute(MDNode *LoopID,
-                                                   StringRef Name) {
+static std::optional<bool> getOptionalBoolLoopAttribute(MDNode *LoopID,
+                                                        StringRef Name) {
   MDNode *MD = findNamedMetadataNode(LoopID, Name);
   if (!MD)
     return std::nullopt;
@@ -750,8 +751,8 @@ bool polly::getBooleanLoopAttribute(MDNode *LoopID, StringRef Name) {
   return getOptionalBoolLoopAttribute(LoopID, Name).value_or(false);
 }
 
-llvm::Optional<int> polly::getOptionalIntLoopAttribute(MDNode *LoopID,
-                                                       StringRef Name) {
+std::optional<int> polly::getOptionalIntLoopAttribute(MDNode *LoopID,
+                                                      StringRef Name) {
   const MDOperand *AttrMD =
       findNamedMetadataArg(LoopID, Name).value_or(nullptr);
   if (!AttrMD)

polly/lib/Transform/ManualOptimizer.cpp

@@ -15,12 +15,12 @@
 #include "polly/Options.h"
 #include "polly/ScheduleTreeTransform.h"
 #include "polly/Support/ScopHelper.h"
-#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/Transforms/Utils/LoopUtils.h"
+#include <optional>
 
 #define DEBUG_TYPE "polly-opt-manual"
 
@@ -40,7 +40,7 @@ static TransformationMode hasUnrollTransformation(MDNode *LoopID) {
   if (getBooleanLoopAttribute(LoopID, "llvm.loop.unroll.disable"))
     return TM_SuppressedByUser;
 
-  Optional<int> Count =
+  std::optional<int> Count =
       getOptionalIntLoopAttribute(LoopID, "llvm.loop.unroll.count");
   if (Count)
     return *Count == 1 ? TM_SuppressedByUser : TM_ForcedByUser;

polly/lib/Transform/Simplify.cpp

@@ -20,6 +20,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Support/Debug.h"
+#include <optional>
 
 #define DEBUG_TYPE "polly-simplify"
 
@@ -758,7 +759,7 @@ class SimplifyWrapperPass final : public ScopPass {
 public:
   static char ID;
   int CallNo;
-  Optional<SimplifyImpl> Impl;
+  std::optional<SimplifyImpl> Impl;
 
   explicit SimplifyWrapperPass(int CallNo = 0) : ScopPass(ID), CallNo(CallNo) {}