https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91001
--- Comment #1 from Shubham Narlawar <gsocshubham at gmail dot com> --- Below is reduced test case after fixing warning. void f(); #pragma pack(1) struct a { short b; char c; }; union{ struct a c; } __attribute__((aligned(128), transparent_union)) d; void e() { f(d); }