https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77992
--- Comment #10 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- If you care about information in bytes that are not part of a field with other semantic significance, you should use -Werror=padded to get errors on structs with padding and use that information to add explicit dummy fields in the source code where there was padding. Once there are explicit dummy fields, their values will be preserved by the compiler, so you can either zero the whole struct with memset and rely on the zeroing of dummy fields not being optimized away, or use a struct initializer and rely on it implicitly zeroing those fields. (Of course this may reduce efficiency as optimizations such as SRA now need to track values of those fields, whereas they do not need to track values of padding.)
