[Bug fortran/22572] Double occurrence of matmul intrinsic not optimised

[tkoenig at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22572

--- Comment #7 from Thomas Koenig <tkoenig at gcc dot gnu.org> 2011-04-22 15:57:01 UTC ---
We should generate

function optmatmul (a, b, c, m, n, count)
  implicit none  
  integer, intent(in) :: m, n, count
  double precision :: optmatmul(m, n)  
  double precision, intent(in) :: a(m, count), b(count, n), c(m, n)
  block
    double precision, dimension(size(a,1), size(b,2)) :: tmp
    tmp = matmul(a,b)
    optmatmul = tmp / (1 + tmp)
  end block
end function optmatmul  

I forsee lots of special-casing here...