[Patch, fortran] PR24518 and PR24520 - Improvements to MOD an d DOT_PRODUCT

[THOMAS Paul Richard 169137]

> It is proposed to retain the library version of the DOT_PRODUCT because
> the inline version does not work for types longer that 8 bytes and for a 
> future implementation, where the library is used with the option -Os.

<<I'm not sure we want to work too much on that -Os option. Anyhow, you
don't know if the guy using -Os will end up linking statically or
dynamically. By the way, are there really people compiling Fortran code and
optimizing for size?>>

I think that I agree with you.  Also, it is not apparent that the library
call does not consume more space.  It's something that I will look into. 

> Unoptimized, the new version of MOD is a factor of two faster than the
> old but the improvement is only 20% for -O2 and more.

<<I'm not sure I understood that. In both cases, the library must be the
same, no? So it sounds like your new version of MOD is slower at high
optimization levels... >>

The existing MOD is inline, as you will see from the patch. I think that it
starts out a bit pessimal and the optimizer does a good job on it.

Best regards

Paul