This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: anti-optimization of _DecimalXX by -ffast-math
- From: Andrew Pinski <pinskia at gmail dot com>
- To: Roman Kononov <roman at binarylife dot net>
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 12 Jan 2010 13:02:40 -0800
- Subject: Re: anti-optimization of _DecimalXX by -ffast-math
- References: <4B4CE2BD.8070805@binarylife.net>
On Tue, Jan 12, 2010 at 12:59 PM, Roman Kononov <roman@binarylife.net> wrote:
> Is there a good reason to place something on the stack? Why does
> -funsafe-math-optimizations (which is a part of -ffast-math) make things
> even worse? It actually swaps the arguments for __bid_adddd3().
Because it turns on re-association which causes a+b to be b+a in your
case. And nothing turns it back for better register allocation.
Thanks,
Andrew Pinski