cvs commit: fptools/ghc/includes TailCalls.h fptools/ghc/rts Schedule.c

[Manuel M. T. Chakravarty]

Simon Marlow <simonmar@microsoft.com> wrote,

> > > BTW, did you try twiddling gcc's -mpreferred-stack-bound 
> > option?  I recall
> > > something from FreeBSD-land about having to tweak this to 
> > eliminate the
> > > extra stack padding instructions.
> > 
> > You are right, -mpreferred-stack-bound might have been a way
> > to get rid of the extra stack padding.  However, AFAIK
> > getting rid of the stack padding means slower code, doesn't
> > it.  Maybe doesn't make that much of a difference, because
> > GHC code doesn't use the system stack much, but still...
> 
> We don't move the stack ptr at all in STG code, except when pushing
> arguments for C calls, so if the stack starts off on a good boundary it'll
> stay that way.

Except if there is a ccall.

Cheers,
Manuel