[clang] [llvm] [PowerPC] Fix codegen for transparent_union function params (PR #101738)

[Hubert Tong via cfe-commits]

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@@ -393,6 +401,18 @@ CharUnits PPC32_SVR4_ABIInfo::getParamTypeAlignment(QualType Ty) const {
   return CharUnits::fromQuantity(4);
 }
 
+ABIArgInfo PPC32_SVR4_ABIInfo::classifyArgumentType(QualType Ty) const {
+  bool IsTransparentUnion;
+  Ty = useFirstFieldIfTransparentUnion(Ty, IsTransparentUnion);
+
+  if (IsTransparentUnion && isPromotableIntegerTypeForABI(Ty))
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hubert-reinterpretcast wrote:

I don't think `isPromotableIntegerTypeForABI` handles enums. We should add a enum test case (maybe with `-fshort-enums`).

https://github.com/llvm/llvm-project/pull/101738