Re: bk commit into maria tree (serg:1.2595)

[Sergei Golubchik]

Hi!

On Apr 03, Davi Arnaut wrote:
> Sergei Golubchik wrote:
> 
> [..]
> 
> > see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html
> > 
> > ChangeSet@stripped, 2008-04-03 17:56:33+02:00, serg@stripped +1 -0
> >   --with-atomic-ops=smp now forces asm, disabling gcc build-ins
> 
> Out of curiosity, why? compiler bugs? Theoretically those built-ins will
> spill out almost the same asm output as the hand coded ones.

Yes. I don't know yet whether it's compiler bug or something is wrong in
my code - but the sympthoms are, with -O3 (to be more presice with three
optimizations enabled at O3) gcc generates incorrect assembler (one
assignment in the loop is jumped over, iirc). It is not a strict
aliasing problem, as far as I could see.

This commit is a quick patch to be able to force assembler routines.
Without --with-atomic-ops configure still uses gcc builtins.

It was not a final bugfix, of course, I still need to fix the bug (I
mean, incorect assembler at -O3).
 
Regards / Mit vielen Grüssen,
Sergei

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