[patch, fortran, RFC] First steps towards inlining matmul

[Thomas Koenig]

Hi Dominique,

> IMO the inlining of MATMUL should be restricted to small matrices (less than 4x4, 9x9
> or 16x16 depending of your field!-)

The problem with the library function we have is that it is quite
general; it can deal with all the complexity of assumed-shape array
arguments.  Inlining allows the compiler to take advantage of
contiguous memory, compile-time knowledge of array sizes, etc.
to allow for vectorization or even complete unrolling.

Of course, if you use c=matmul(a,b) where all three are assumed-shape
arrays, your advantage over the library function will be minimal at
best.

It will be interesting to see at what size calling BLAS directly
will be better.

	Thomas