[parisc-linux] [PATCH] fix SMP TLB optimisations

[John David Anglin]

> > > Don't like what's going on with fr22 in the above code.  Seems like a
> > > GCC optimization bug since it looks like there are a few general registers
> > > that could be used.
> > 
> > Why a bug? It's a register just like any other.
> 
> It's an optimization bug because copying from a general to a floating
> register has to be done through memory.  A stack local would save
> a read and write.  In this case, all the manipulation is done before
> the syscall and there would appear to be sufficient general registers
> available to do the job.  GCC's register allocator should be smart
> enough to figure this out...

With luck, his problem should be fixed:
http://gcc.gnu.org/ml/gcc-patches/2007-03/msg00335.html

Also, the 64-bit kernel should use fp regs only for xmpyu.

Dave
-- 
J. David Anglin                                  dave.anglin at nrc-cnrc.gc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6602)