matmul, dotprod, transpose performance patch proposal

[Tim Prince]

I have been examining performance improvements which can be obtained by 
1st step optimizations of these intrinsics.  I'm sure it's no secret, 
that a performance increase can be obtained by usual methods:

matmul_r[48]:  unroll and jam the stride 1 loops, combining 2 outer loop 
iterations in one inner loop.  For Pentium-M, but not for Xeon, Opteron, 
or Itanium, a much bigger boost is obtained by using 2 parallel dot 
products.  Change the general stride case to dot product, dictating the 
strength reduction which gfortran misses.  20% to 100% gain in performance

dotprod_r[48]:  unroll, performing addition in pairs first, before 
adding to sum accumulation, effectively cutting the performance 
limitation due to latency of addition in half.  Typical 30% performance gain

transpose:  swap inner and outer loops, so the small stride (normally 1) 
occurs on the destination rather than the source side, taking advantage 
of Write Combine buffering, where present.  This should be faster, as 
long as the operand size is not large enough for cache eviction to 
become important.

Woould such a patch be offered,, under what circumstance?