gcc/testsuite/gfortran.dg/nosigned_zero_1.f90

   1 ! { dg-do run }
   2 !
   3 ! PR fortran/40675
   4 !
   5 ! Fortran 77 just had: "The value of a signed zero is the same as
   6 ! the value of an unsigned zero." and g77 returned for SIGN(1.0, -0.0) = 1.0
   7 !
   8 ! Fortran 95+ has for SIGN: "Case  (iv):  If B is of type real and is zero,
   9 ! then ... (c) If B is negative real zero, the value of the result is -|A|".
  10 ! On architectures, where signed zeros are supported, gfortran's SIGN thus
  11 ! returns for B=-0.0 the -|A|.
  12 !
  13 program s
  14    x = sign(1.,0.)
  15    y = sign(1.,-0.)
  16    if (x /=  1.) STOP 1
  17    if (y /= -1.) STOP 2
  18    x = 1.
  19    y = 0.
  20    x = sign(x, y)
  21    y = sign(x, -y)
  22    if (x /=  1.) STOP 3
  23    if (y /= -1.) STOP 4
  24 end program s