https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66907
Bug ID: 66907
Summary: Correct code produces "Segmentation fault - invalid
memory reference"
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: mrestelli at gmail dot com
Target Milestone: ---
The attached code compiles with gfortran and produces an error at
runtime. As far as I can see, the code is correct. Unfortunately, I
have been unable to reduce the test further; if I try, the problem
disappears.
$ gfortran gft.f90 -g -O0 -o gft
$ ./gft
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
Backtrace for this error:
#0 0x7F281A1F6757
#1 0x7F281A1F6D5E
#2 0x7F281972EE8F
#3 0x400A15 in __mod_a_MOD_mult at gft.f90:67
#4 0x400F44 in __mod_a_MOD_check_t_b at gft.f90:38 (discriminator 2)
#5 0x401160 in test at gft.f90:84 (discriminator 2)
Speicherzugriffsfehler
$ gfortran --version
GNU Fortran (GCC) 6.0.0 20150715 (experimental)
Copyright (C) 2015 Free Software Foundation, Inc.
The correct behaviour should be
$ ./gft
p(1): 1
p(2): 1
I can see the same problem also with versions 5.1.0 and 4.9.2.
module mod_a
implicit none
type t_a
integer :: i
end type t_a
type :: t_b
type(t_a), allocatable :: dat(:)
end type t_b
interface assignment(=)
module procedure real2t_b
end interface
interface operator(**)
module procedure pow
end interface
interface operator(*)
module procedure mult
end interface
contains
pure recursive function check_t_b(d) result(b)
integer, intent(in) :: d
type(t_b) :: b(2)
type(t_b) :: xd
xd = 1.0
if(d.eq.1) then
b = 1.0
else
b = (xd**0)*check_t_b(1)
endif
end function check_t_b
elemental subroutine real2t_b(p,x)
type(t_b), intent(out) :: p
real, intent(in) :: x
allocate(p%dat(1))
p%dat%i = 1.0
end subroutine real2t_b
elemental function pow(p,n) result(q)
type(t_b) :: q
type(t_b), intent(in) :: p
integer, intent(in) :: n
q = 1.0
end function pow
elemental function mult(p1,p2) result(p)
type(t_b), intent(in) :: p1,p2
type(t_b) :: p
type(t_a) :: p1_dat
p1_dat = p1%dat(1)
p = 1.0
end function mult
end module mod_a
!-----------------------------------------------------------------------
program test
use mod_a
implicit none
type(t_b) :: p(2)
p = check_t_b( 2 )
write(*,*) "p(1): ", p(1)%dat%i
write(*,*) "p(2): ", p(2)%dat%i
end program test
