https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92178
--- Comment #14 from anlauf at gcc dot gnu.org ---
I looked at cases with character arguments, and it appears that there is a
general issue with (lack or improper) generation of temporaries. Consider:
program p
implicit none
character(4), allocatable :: a(:)
integer :: k = -999
a = ["aa","bb"]
! call assign_s (a, (a(2) // "")) ! OK
! call assign_s (a, a(2) // "" ) ! OK
! call assign_s (a, (a(2))) ! no proper temporary
! call assign_s (a, a(2) ) ! invalid Fortran
call assign_s (a, (a(2)(1:3))) ! no proper temporary
print *, allocated (a), k
contains
subroutine assign_s (a, b)
character(*), allocatable, intent(out) :: a(:)
! character(*), value :: b ! rejected (-> pr110290)
character(*) :: b
k = len (b)
print *, b
end subroutine
end
The first two variants work as expected, the fourth is IMHO invalid because
of aliasing, but the third and fifth should work.
However, compiling with -fsanitize=address,undefined shows that they don't.
Inspecting the dump-tree suggests that there is no proper temporary for the
second argument, even though it is requested. Also, running under gdb,
I see that the gfc_evaluate_now from the patch is called.
Do we need to do something special to get temporaries here?
