gcc/testsuite/gfortran.dg/nosigned_zero_2.f90

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