https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107157
Bug ID: 107157
Summary: Weird out-of-bounds error with multiple move_alloc's
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: federico.perini at gmail dot com
Target Milestone: ---
I'm in trouble reducing this problem to a minimum viable example, so I'm asking
for help - I have a nested derived type that contains allocatable components,
like:
type :: string
character(len=1), allocatable :: t(:)
end type string
type :: data_point
type(string) :: name
real(real64), allocatable :: data(:)
end type data_point
type :: data_set
type(data_point), allocatable :: data(:)
end type data_set
Now, I read in type(data_set) from several input files, and I grow that using a
move_alloc, this way:
subroutine read_dataset(this,fileName)
class(data_set), intent(inout) :: this
character(*), intent(in) :: fileName
type(data_point), allocatable :: tmp(:)
type(data_point) :: this_file
[...]
read_data: do
n = n+1
! Read one
call this_file%read(blabla)
! Extend & copy
allocate(tmp(n))
if (n>1) tmp(1:n-1) = this%data(1:n-1)
tmp(n) = this_file
call move_alloc(from=tmp,to=this%data)
end do read_data
end subroutine
Starting from n>=2, after the routine exits, I have this error:
```
Fortran runtime error: Index '1' of dimension 1 of array '_F.DA0' outside of
expected range (0:0)
```
- the error points to the end line of the module ("end module blabla")
- I have no structures with that '_F.DA0' name, nor I can find anything like
that in a text search in the .mod file (after unzipping it)
- No error if move_alloc is called at most once
I would like to reduce the problem to a simpler case I can post but I haven't
been able to reproduce this so I'm asking for help:
is there any compiler flags I can turn on to produce more output and/or
understand better what's going on?
Thank you in advance,
Federico
