gcc/testsuite/gfortran.dg/pr41212.f90

   1 ! { dg-do run }
   2 ! { dg-options "-O2" }
   3 program m
   4    double precision :: y,z
   5    call b(1.0d0,y,z)
   6    if (ABS (z - 1.213) > 0.1) STOP 1
   7 contains
   8      subroutine b( x, y, z)
   9        implicit none
  10        double precision :: x,y,z
  11        integer :: i, k
  12        double precision :: h, r
  13
  14        y = 1.0d0
  15        z = 0.0d0
  16
  17        h = 0
  18        DO k = 1,10
  19           h = h + 1.0d0/k
  20
  21           r = 1
  22           DO i = 1,k
  23              r = (x/(2*i) ) * r
  24           END DO
  25
  26           y = y + (-1)**k * r
  27           z = z + (-1)**(k+1) * h * r
  28
  29           IF ( ABS(2*k/x*r) < 1d-6 ) EXIT
  30        END DO
  31
  32        z = 2*y
  33      end subroutine b
  34 end program m