Subject: Re: I want to rid ugly float load/stores used only for data movement
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: None <firstname.lastname@example.org>
Date: 03/03/2003 00:48:32
> > BTW, Mouse: GCC already avoids this tactic on chips for which FP
> > registers do not hold arbitrary values (i386, m68k, to name a
> > couple). Please, give them _some_ credit.
> Um, then, I guess I don't understand. Surely it's easy enough to avoid
> it on any machine, then, just by telling gcc that the FP registers work
> like the i386 or m68k FP registers and can't hold arbitrary values? I
> thought someone said that it was difficult to teach gcc to not do this,
> which seemed at odds with gcc already knowing how to not do this.
er, sorry, I should have directed that comment at David, since it was
his misinformation that prompted your original comment.
In any case, there is definitely a problem with GCC using FP registers on
PPC to do 64-bit moves, it has definitely been dealt with in the Wind River
edition of GCC, and I am pretty sure the FSF squashed it in their GCC at
some point as well.
toddpw @ toddpw.org