https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98577
kargl at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|WONTFIX |INVALID
--- Comment #16 from kargl at gcc dot gnu.org ---
(In reply to Chinoune from comment #15)
> Bug is a bug!
It's not a bug if the behavior is documented.
What does Intel do with this standard conforming program?
program foo
use iso_fortran_env, only : int32, int64, real64
implicit none
integer(int32) rate4, t1, t2
integer(int64) rate8, u1, u2
!
! Both Intel and gfortran should give the same timings as
! COUNT and COUNT_RATE variables have the same kind type
! parameter. This is documented by both gfortran and Intel.
!
print '(A)', 'Behavior documented to give valid timings with gfortran and
Intel'
call system_clock(count_rate=rate4)
print '(A,I0)', 'rate4 = ', rate4
call system_clock(count_rate=rate8)
print '(A,I0)', 'rate8 = ', rate8
call system_clock(count=t1)
call loop
call system_clock(count=t2)
print '(A,F0.3,A)', 'time = ', real(t2-t1,real64)/rate4, ' seconds
(int32/int32)'
call system_clock(count=u1)
call loop
call system_clock(count=u2)
print '(A,F0.3,A)', 'time = ', real(u2-u1,real64)/rate8, ' seconds
(int64/int64)'
!
! gfortran gives an invalid time with the following, but gfortran
! also documents the behavior. What does Intel do?
!
print *
print '(A)', 'Behavior documented to give invalid timings with gfortran'
call system_clock(count_rate=rate8)
print '(A,I0)', 'rate8 = ', rate8
call system_clock(count=t1)
call loop
call system_clock(count=t2)
print '(A,F0.3,A)', 'time = ', real(t2-t1,real64)/rate8, ' seconds
(int32/int64)'
call system_clock(count_rate=rate4)
print '(A,I0)', 'rate4 = ', rate4
call system_clock(count=u1)
call loop
call system_clock(count=u2)
print '(A,F0.3,A)', 'time = ', real(u2-u1,real64)/rate4, ' seconds
(int64/int32)'
contains
subroutine loop
implicit none
real(real64) dx, x, y
integer i
integer, parameter :: n = 100000001
dx = 1._real64 / (n - 1)
do i = 1, n
x = 1000 + (i - 1) * dx
y = cos(x)
x = sin(x)
if (x * y > 2) stop 1
end do
end subroutine loop
end program foo
