On Tue, Dec 03, 2019 at 10:33:48PM +0900, Oleg Endo wrote:
> On Mon, 2019-11-25 at 16:47 -0600, Segher Boessenkool wrote:
> >
> > > > - sh (that's sh4-linux):
> > > >
> > > > /home/segher/src/kernel/net/ipv4/af_inet.c: In function
> > > > 'snmp_get_cpu_field':
> > > > /home/segher/src/kernel/net/ipv4/af_inet.c:1638:1: error: unable to
> > > > find a register to spill in class 'R0_REGS'
> > > > 1638 | }
> > > > | ^
> > > > /home/segher/src/kernel/net/ipv4/af_inet.c:1638:1: error: this is the
> > > > insn:
> > > > (insn 18 17 19 2 (set (reg:SI 0 r0)
> > > > (mem:SI (plus:SI (reg:SI 4 r4 [178])
> > > > (reg:SI 6 r6 [171])) [17 *_3+0 S4 A32]))
> > > > "/home/segher/src/kernel/net/ipv4/af_inet.c":1638:1 188 {movsi_i}
> > > > (expr_list:REG_DEAD (reg:SI 4 r4 [178])
> > > > (expr_list:REG_DEAD (reg:SI 6 r6 [171])
> > > > (nil))))
> > > > /home/segher/src/kernel/net/ipv4/af_inet.c:1638: confused by earlier
> > > > errors, bailing out
> > >
> > > Would have to look more at this one. Seems odd that it can't allocate
> > > R0 when it's already the destination and when R0 can't be live before
> > > the insn. But there again, this is reload, so my enthuasiasm for looking
> > > is a bit limited :-)
> >
> > It wants to use r0 in some other insn, so it needs to spill it here, but
> > cannot. This is what class_likely_spilled is for.
>
> Hmm ... the R0 problem ... SH doesn't override class_likely_spilled
> explicitly, but it's got a R0_REGS class with only one said reg in it.
> So the default impl of class_likely_spilled should do its thing.
Yes, good point. So what happened here? Is it just RA messing things
up, unrelated to the new pass?
Segher
