I'm not completely sure that the following code is invalid, but I think it is.
Taken from:
http://home.comcast.net/%7Ekmbtib/Fortran_stuff/cyclic_specs1.f90
g95 prints:
Error: Circular specification in variable 'ouch' at (1)
NAG f95 compiles it without any warning/error, however. Running it (using all
checks) shows either an empty line or
CHARACTER actual arg LEN=4 shorter than dummy arg LEN=1963731936
which indicates that it is indeed invalid.
Here is the source:
! File: cyclic_specs1.f90
! Public domain 2004 James Van Buskirk
! Leads to internal compiler error in g95
! Windows download of 12/18/04
module cyclic
implicit none
contains
function ouch(x,y)
implicit character(len(ouch)) (x)
implicit character(len(x)+1) (y)
implicit character(len(y)-1) (o)
intent(in) x,y
character(len(y)-1) ouch
integer i
do i = 1, len(ouch)
ouch(i:i) = achar(ieor(iachar(x(i:i)),iachar(y(i:i))))
end do
end function ouch
end module cyclic
program test
use cyclic
implicit none
write(*,*) ouch('YOW!',' ')
end program test
--
Summary: Endless loop when compiling a cyclic code
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Keywords: ice-on-invalid-code
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: burnus at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31294
