http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57957
janus at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |janus at gcc dot gnu.org
Summary|Double free with |[F03] Double free with
|allocatable components |allocatable components
--- Comment #2 from janus at gcc dot gnu.org ---
(In reply to Tobias Burnus from comment #1)
> For GCC 4.9, one needs to wrap the code in the main program in BLOCK/END
> BLOCK as otherwise the end-of-scope deallocation does not trigger, which
> causes the failure.
Updated test case:
program main
implicit none
type :: type1
real, allocatable :: anum(:)
end type
type :: type2
type(type1) :: temp
end type
block
type(type1) :: t1
type(type2) :: t2
t1 = type1([0.,1.])
t2 = type2(t1)
end block
end
Note: The double free goes away when changing the line
t2 = type2(t1)
to
t2%temp = t1
That means the actual problem is not the auto-dealloc itself (which is done
properly), but the construction of t2: With the second variant, a deep copy is
done (allocating a separate chunk of memory for t2%temp), while in the first
one t2%temp only gets a reference to the memory allocated for t1 (which is of
course wrong). Since both t1 and t2 are auto-deallocated, we try to free that
memory twice.
