Wrap some operators in #ifndef __swift__ guards.

Swift C++ interop has a bug where certain operator declarations cannot be
imported successfully due to percieved circular references in the declarations.
Since these declarations are already dropped by the ClangImporter, it's helpful
to hide the declarations entirely from Swift to avoid spurious diagnostics that
cannot be addressed. See swiftlang/swift#71032 for a
similar workaround in the Swift compiler implementation.

Author: tshortli

clang/include/clang/AST/DependentDiagnostic.h

@@ -147,9 +147,11 @@ class DeclContext::ddiag_iterator {
     return tmp;
   }
 
+#ifndef __swift__
   bool operator==(ddiag_iterator Other) const {
     return Ptr == Other.Ptr;
   }
+#endif
 
   bool operator!=(ddiag_iterator Other) const {
     return Ptr != Other.Ptr;

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

@@ -5623,7 +5623,9 @@ struct AAPointerInfo : public AbstractAttribute {
 
     unsigned size() const { return Ranges.size(); }
 
+#ifndef __swift__
     bool operator==(const RangeList &OI) const { return Ranges == OI.Ranges; }
+#endif
 
     /// Merge the ranges in \p RHS into the current ranges.
     /// - Merging a list of  unknown ranges makes the current list unknown.
@@ -5757,11 +5759,13 @@ struct AAPointerInfo : public AbstractAttribute {
     Access(const Access &Other) = default;
 
     Access &operator=(const Access &Other) = default;
+#ifndef __swift__
     bool operator==(const Access &R) const {
       return LocalI == R.LocalI && RemoteI == R.RemoteI && Ranges == R.Ranges &&
              Content == R.Content && Kind == R.Kind;
     }
     bool operator!=(const Access &R) const { return !(*this == R); }
+#endif
 
     Access &operator&=(const Access &R) {
       assert(RemoteI == R.RemoteI && "Expected same instruction!");

llvm/include/llvm/Transforms/IPO/SampleContextTracker.h

@@ -161,13 +161,15 @@ class SampleContextTracker {
       return *this;
     }
 
+#ifndef __swift__
     bool operator==(const Iterator &Other) const {
       if (NodeQueue.empty() && Other.NodeQueue.empty())
         return true;
       if (NodeQueue.empty() || Other.NodeQueue.empty())
         return false;
       return NodeQueue.front() == Other.NodeQueue.front();
     }
+#endif
 
     ContextTrieNode *operator*() const {
       assert(!NodeQueue.empty() && "Invalid access to end iterator");