gmp-4.2 performance on x86_64

[Kate Minola]

On my 2.2GHz x86_64-unknown-linux-gnu machine
I get the following gmpbench results:

  gmp-4.1.4-gaudry  7863.2
  gmp-4.2           7375.2
  gmp-4.1.4         4645.6

gmp-4.1.4-gaudry is using the assembly code by
Patrick Gaudry at

  http://www.loria.fr/~gaudry/mpn_AMD64/

All were compiled with the same compiler, gcc-4.1.0.

While I want to use gmp-4.2 to pick up bug fixes, I do not
want to lose the speed of gmp-4.1.4-gaudry.

Doing the obvious to use Gaudry's assembler code in gmp-4.2
causes a failure to compile (for me).

Comments?  Suggestions?

Kate Minola
Engineering Department
University of Maryland, College Park