https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100440
anlauf at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-05-08
Ever confirmed|0 |1
Keywords| |wrong-code
--- Comment #9 from anlauf at gcc dot gnu.org ---
(In reply to Steve Kargl from comment #7)
> There is no default initialization in the code below. default
> initialization is
>
> type foo
> integer :: i = 1 ! <-- Default initialization
> end tyep foo
The F2018 standard says:
7.5.4.6 Default initialization for components
[...] Allocatable components are always initialized to unallocated.
Anyway, the following extension shows that default initialization does not
work:
program p
implicit none
type fm
real, allocatable :: mp(:)
integer :: dummy = 42
end type
type(fm), allocatable :: a(:,:)
integer :: n = 1
allocate (a(n,n))
a = mm (a, a)
a = mm (a, a) ! crashes here with -fsanitize=address
contains
function mm (ma, mb)
type(fm) :: ma(:,:), mb(:,:)
type(fm), dimension(size(ma,dim=1),size(mb,dim=2)) :: mm
integer :: i, j
! type(fm), dimension(size(ma,dim=1),size(mb,dim=2)) :: z
! mm = z ! Explicit initialization of function result
do i = 1, size(ma,dim=1)
do j = 1, size(mb,dim=2)
print *, i, j, allocated (mm(i,j)% mp), mm(i,j)% dummy
end do
end do
end function mm
end program p
Which gives:
1 1 F 0
1 1 T 0
and with MALLOC_PERTURB_=2 :
1 1 T -33686019
1 1 T -33686019
Uncommenting the indicated lines in function mm procduces:
1 1 F 42
1 1 F 42
and crashes with MALLOC_PERTURB_=2
Not good.
