On Sat, Aug 20, 2011 at 5:47 PM, Uros Bizjak <ubiz...@gmail.com> wrote: > On Sun, Aug 21, 2011 at 1:58 AM, Richard Henderson <r...@redhat.com> wrote: >> On 08/20/2011 03:03 PM, H.J. Lu wrote: >>> On Sat, Aug 20, 2011 at 3:02 PM, H.J. Lu <hjl.to...@gmail.com> wrote: >>>>> You can do better than this, and avoid the %M %N specifiers. >>>>> The outputs are truly independent and do not need to be a pair. >>>>> >>>> >>>> Since RA use register pairs for TImode/DImode, should requiring >>>> TI/DI registers in pairs generate better does? >>> ^^^^^^ codes. >>> >>> Without register pairs, we are generating very strange codes. >>> >> >> We ought to be making better use of the lower-subregs pass. >> Representing independent outputs when possible enables that. >> >> Admittedly, the i386 port needs more attention to really make >> this happen properly. But we don't need to make things even >> worse in the meantime. > > I will investigate this. >
One problem is 32bit movdi and 64bit movti. They require register pairs.We may need to split them before RA. -- H.J.
