Sign2CodeTrans generates invalid code for an array argument

[arporter]

Simon has reported that Sign2CodeTrans produces invalid code when applied to a SIGN that has an array as argument. One of the examples of this is from src/OCE/SBC/sbcblk_algo_andreas.F90 in NEMO from which I've constructed the following:

    program test_prog
      integer, parameter :: wp = kind(1.0d0)
      integer, parameter, dimension(0:4) :: A2D = (/1, 2, 3, 4, 5/)
      REAL(wp), DIMENSION(A2D(0)) :: ztmp1
      ztmp1 = 0.0
      ztmp1 = SIGN( MAX(ABS(ztmp1),1.E-6_wp), ztmp1 )
    end program test_prog'''

[arporter]

The code PSyclone currently generates for this is:

  tmp_abs = MAX(ABS(ztmp1), 1.e-6_wp)
  if (tmp_abs > 0.0) then
    res_abs = tmp_abs
  else
    res_abs = tmp_abs * -1.0
  end if
  res_sign = res_abs
  tmp_sign = ztmp1
  if (tmp_sign < 0.0) then
    res_sign = res_sign * -1.0
  end if
  ztmp1 = res_sign

and the problem is that tmp_abs is declared as a scalar but MAX(ABS(ztmp1), 1.0E-6) is an array.

[arporter]

What we should generate is:

do i in shape
  tmp_abs = MAX(ABS(ztmp1(i)), 1.e-6)
  if (tmp_abs > 0.0) then
    res_abs = tmp_abs
  else
    res_abs = tmp_abs * -1.0
  end if
  res_sign = res_abs
  tmp_sign = ztmp1(i)
  ...
  ztmp1(i) = res_sign
end do

[arporter]

Alternatively, could we apply Reference2ArrayRangeTrans to

  ztmp1 = SIGN( MAX(ABS(ztmp1),1.E-6_wp), ztmp1 )

to get:

  ztmp1(:) = SIGN( MAX(ABS(ztmp1(:)),1.E-6_wp), ztmp1(:) )

and then ArrayAssignment2LoopsTrans to get:

  do i = 1, ...
     ztmp1(i) = SIGN(MAX(ABS(ztmp1(i)), 1.E-6_wp), ztmp1(i))
  end do

At which point, the Sign2CodeTransformation should work OK?

[arporter]

The transformation itself had a comment saying we assume that the argument is a real scalar because we can't query the datatype (with a reference to an old issue). I've closed that old issue (#658) and am proceeding to do better. However, I immediately hit the fact that we don't know what the return type of MAX or ABS is and so the datatype of the argument to SIGN comes back as UnresolvedType. We hit this situation because we can't get the datatype of MAX and ABS as they are Calls.

[arporter]

It turns out that ABS2CodeTrans made the same assumption about operating on a scalar, real argument so I've generalised my fix (validation really) so that it is used there too.