[Bug fortran/31009] New: derived type components: use memcpy when assigning arrays

["dfranke at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

In January, there were two patches from Roger Sayle [1,2] which were quite an
improvement for me. I'd like to suggest to do the same for derived type
components. Example:

TYPE :: summed_amplitude
  COMPLEX, DIMENSION(:,:), POINTER :: alm
END TYPE

SUBROUTINE summed_amplitude_init_copy(this, other)
  TYPE(summed_amplitude), INTENT(out) :: this
  TYPE(summed_amplitude), INTENT(in)  :: other
  ALLOCATE(this%alm(size(other%alm,1), size(other%alm,2)))
  this%alm = other%alm
END SUBROUTINE

Here, gfortran copies the arrays element-wise. In my code, this accounts for
about 20% of the runtime (as shown by gprof).

[1] http://gcc.gnu.org/ml/fortran/2007-01/msg00113.html (implement a(:) = b(:)
using memcpy when possible)
[2] http://gcc.gnu.org/ml/fortran/2007-01/msg00419.html (Use memcpy for array
constructor assignments)


-- 
           Summary: derived type components: use memcpy when assigning
                    arrays
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dfranke at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31009