[Bug gcov-profile/43341] pragma pack changes padding in struct gcov_info on 64-bit archs

[arthur.j.odwyer at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43341

--- Comment #6 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> 2011-04-26 20:18:42 UTC ---
(In reply to comment #5)
> (In reply to comment #4)
> > gcc -fpack-struct=4 -fprofile-generate test.c
> 
> -fpack-struct changes the ABI so it is not fully a bug there.

It's a gray area. -fprofile-generate is not documented as relying on "structs",
as far as I could tell, so it's not intuitively obvious that it should have any
interaction with -fpack-struct= at all. IMHO -fprofile-generate should always
produce working code. At the very least, the interaction should be documented
in the documentation for -fprofile-generate.

The same pitfalls also apply to -fprofile-arcs.