https://gcc.gnu.org/bugzilla/show_bug.cgi?id=34678
Thomas Koenig <tkoenig at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |105105
--- Comment #47 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
(In reply to Thomas Koenig from comment #46)
> Fortran gets this right:
... but only by accident. This test case shows that it doesn't:
$ cat y.f90
module y
implicit none
integer, parameter :: wp = selected_real_kind(15)
contains
subroutine foo(a,b,c)
use ieee_arithmetic
real(kind=wp), dimension(4), intent(out) :: a
real(kind=wp), intent(in) :: b, c
type (ieee_round_type), dimension(4), parameter :: mode = &
[ieee_nearest, ieee_to_zero, ieee_up, ieee_down]
call ieee_set_rounding_mode (mode(1))
a(1) = b + c
call ieee_set_rounding_mode (mode(2))
a(2) = b + c
call ieee_set_rounding_mode (mode(3))
a(3) = b + c
call ieee_set_rounding_mode (mode(4))
a(4) = b + c
end subroutine foo
end module y
program main
use y
real(kind=wp), dimension(4) :: a
call foo(a, 0.1_wp, 0.2_wp)
print *,a
end program main
$ gfortran -O y.f90 && ./a.out
0.30000000000000004 0.30000000000000004 0.30000000000000004
0.30000000000000004
$ gfortran y.f90 && ./a.out
0.30000000000000004 0.29999999999999999 0.30000000000000004
0.29999999999999999
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105105
[Bug 105105] [Meta] Fortran IEEE support
