[Bug debug/48459] [4.6/4.7 Regression] avr: Assertion failure with -gdwarf-2

["anitha.boyapati at atmel dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48459

--- Comment #10 from Anitha Boyapati <anitha.boyapati at atmel dot com> 2011-06-10 07:37:19 UTC ---
(In reply to comment #9)
> (In reply to comment #8)
> > I agree. But this does not fully solve the problem either.
> > INCOMING_RETURN_ADDR_RTX is being defined in dwarf2out.c to gcc_unreachable()
> > :-(
> 
> Why is initial_return_save still being called?  My patch should prevent
> debug_unwind_info from returning UI_DWARF2.


Preprocessed output of default_debug_unwind_info()

enum unwind_info_type
default_debug_unwind_info (void)
{
# 1356 "../../gcc/targhooks.c"
  return UI_NONE;
}


I don't think  initial_return_save() is called now. It passes the compilation
there but gets struck in other places. I think it is because
INCOMING_RETURN_ADDR_RTX is now seen as defined and hence CFI info is emitted.
But this runs into trouble because the above hook is gcc_unreachable().