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

[pinskia at gcc dot gnu.org]

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

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-04-26 20:24:21 UTC ---
(In reply to comment #6)
> (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.

Maybe it does not says it relays on structs but it relays on the current ABI
that is used.  This is just like saying the Fortran front-end does say it
relays on structs but things go bad when you use that option.  I don't see why
this should be documented when it is already documented that -fpack-struct
changes the ABI.