[Bug fortran/100656] ICE in gfc_conv_expr_present, at fortran/trans-expr.c:1934

[anlauf at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100656

--- Comment #2 from anlauf at gcc dot gnu.org ---
Using a temporary may help:

subroutine s(x)
  character(:), allocatable, optional :: x(:)
  character(:), allocatable           :: y(:)
  if ( present(x) ) then
     if ( allocated(x) ) then
        y = 'a' // x // 'e'
        x = y
     end if
  end if
end

This does not ICE.