[llvm-branch-commits] [CodeGen][CFI] Generalize transparent union parameters (PR #158193)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/158193

According GCC documentation transparent union
calling convention is the same as the type of the
first member of the union.

C++ ignores attribute.