blob: 971cd634a5fa8e32f69f00cd35f92ed037e5bfbe [file] [log] [blame]
 ! { dg-do run } ! PR 83064 - this used to give wrong results. ! { dg-additional-options "-O1 -ftree-parallelize-loops=2" } ! Original test case by Christian Felter program main use, intrinsic :: iso_fortran_env implicit none integer, parameter :: nsplit = 4 integer(int64), parameter :: ne = 2**20 integer(int64) :: stride, low(nsplit), high(nsplit), i real(real64), dimension(nsplit) :: pi integer(int64), dimension(:), allocatable :: edof allocate (edof(ne)) edof(1::4) = 1 edof(2::4) = 2 edof(3::4) = 3 edof(4::4) = 4 stride = ceiling(real(ne)/nsplit) do i = 1, nsplit high(i) = stride*i end do do i = 2, nsplit low(i) = high(i-1) + 1 end do low(1) = 1 high(nsplit) = ne pi = 0 do concurrent (i = 1:nsplit) pi(i) = sum(compute( low(i), high(i) )) end do if (abs (sum(pi) - atan(1.0d0)) > 1e-5) stop 1 contains pure function compute( low, high ) result( ttt ) integer(int64), intent(in) :: low, high real(real64), dimension(nsplit) :: ttt integer(int64) :: j, k ttt = 0 ! Unrolled loop ! do j = low, high, 4 ! k = 1 ! ttt(k) = ttt(k) + (-1)**(j+1) / real( 2*j-1 ) ! k = 2 ! ttt(k) = ttt(k) + (-1)**(j+2) / real( 2*j+1 ) ! k = 3 ! ttt(k) = ttt(k) + (-1)**(j+3) / real( 2*j+3 ) ! k = 4 ! ttt(k) = ttt(k) + (-1)**(j+4) / real( 2*j+5 ) ! end do ! Loop with modulo operation ! do j = low, high ! k = mod( j, nsplit ) + 1 ! ttt(k) = ttt(k) + (-1)**(j+1) / real( 2*j-1 ) ! end do ! Loop with subscripting via host association do j = low, high k = edof(j) ttt(k) = ttt(k) + (-1.0_real64)**(j+1) / real( 2*j-1 ) end do end function end program main