Re: raid 5 with >= 5 members broken on x86

[Alexandre Oliva <aoliva@redhat.com>]

On Feb 26, 2004, Linus Torvalds <torvalds@osdl.org> wrote:

> Ok. I did the silly one-liner, but if the "don't care" approach really 
> improves code generation, feel free to send one that fixes both the P5 and 
> PII cases..

FWIW, I think the silly one-liner is actually an improvement, since
then we use a hardware register for the counter, instead of a stack
location.  I was concerned about not increasing the register pressure
with the patch; it looked very tight already, and I couldn't tell it
wouldn't be exceeded with some older compiler that failed to eliminate
the frame pointer, for example.

If that's the way to go, I'll post a patch that leaves the +r alone.
If using a stack location for the counter could possibly be as
efficient as using a register, I'd convert  "+r" (lines) to "+g".  Any
preferences?

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Happy GNU Year!                     oliva@{lsd.ic.unicamp.br, gnu.org}
Red Hat GCC Developer                 aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist                Professional serial bug killer