[clang] [Clang] Consider preferred_type in bitfield warnings (#116760) (PR #116785)

[Mariya Podchishchaeva via cfe-commits]

================
@@ -10509,14 +10516,18 @@ static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
                  ED->getNumPositiveBits() == FieldWidth) {
         DiagID = diag::warn_signed_bitfield_enum_conversion;
       }
-
+      unsigned PreferredTypeDiagIndex = PTAttr != nullptr;
       if (DiagID) {
-        S.Diag(InitLoc, DiagID) << Bitfield << ED;
+        S.Diag(InitLoc, DiagID) << Bitfield << PreferredTypeDiagIndex << ED;
         TypeSourceInfo *TSI = Bitfield->getTypeSourceInfo();
         SourceRange TypeRange =
             TSI ? TSI->getTypeLoc().getSourceRange() : SourceRange();
         S.Diag(Bitfield->getTypeSpecStartLoc(), diag::note_change_bitfield_sign)
             << SignedEnum << TypeRange;
+        if (PTAttr) {
+          S.Diag(PTAttr->getLocation(), diag::note_bitfield_preferred_type)
+              << ED;
+        }
----------------
Fznamznon wrote:

```suggestion
        if (PTAttr)
          S.Diag(PTAttr->getLocation(), diag::note_bitfield_preferred_type)
              << ED;
```

https://github.com/llvm/llvm-project/pull/116785