On Thu, Aug 08, 2024 at 07:57:43AM -0600, Jeff Law wrote:
>
>
> On 8/8/24 6:26 AM, Stefan Schulze Frielinghaus wrote:
> > On Thu, Aug 08, 2024 at 06:03:13AM -0600, Jeff Law wrote:
> > >
> > >
> > > On 8/8/24 5:15 AM, Stefan Schulze Frielinghaus via Gcc wrote:
> > >
> > > >
> > > > However `(reg:DI 61 [ MEM[(const union T *)p_2(D)] ])` referencing the
> > > > same pseudo in a different mode is not substituted in insn 6 which
> > > > leads in the following to an error. The insn is emitted in
> > > > s390_expand_insv() during
> > > There can only be a single instance of a given pseudo, if you have
> > > multiple
> > > instances, that's the bug.
> >
> > Yeah I was fearing this might be the culprit.
> It doesn't come up much, but I've stumbled across it a few times through the
> years. It comes up less often than sharing nodes that aren't supposed to be
> shared though.
>
> You know we probably could build a checker for this. Walk the IL (prior to
> register allocation) and for every pseudo referenced, see if it compares
> equal to regno_reg_rtx[regnum], if not ICE. Probably could be embedded in
> one of the existing RTL checking phases with minimal cost.
Since you installed this idea into my brain, I gave it a try. Maybe something
along the lines:
void
verify_references_to_pseudos ()
{
basic_block bb;
FOR_EACH_BB_FN (bb, cfun)
{
rtx_insn *insn;
FOR_BB_INSNS (bb, insn)
{
subrtx_iterator::array_type array;
FOR_EACH_SUBRTX (iter, array, PATTERN (insn), NONCONST)
{
const_rtx reg = *iter;
if (!reg || !REG_P (reg))
continue;
int regno = REGNO (reg);
/* Hard registers may be referenced in different modes. */
if (HARD_REGISTER_NUM_P (regno))
continue;
rtx orig_reg = regno_reg_rtx[regno];
machine_mode m1 = GET_MODE (orig_reg);
machine_mode m2 = GET_MODE (reg);
if (m1 != m2)
internal_error (
"pseudo %i defined for mode %s but referenced in "
"mode %s in insn %i", regno, GET_MODE_NAME (m1),
GET_MODE_NAME (m2), INSN_UID (insn));
}
}
}
}
I haven't tested it extensively but it triggers at least for the current case.
I would have loved to also print the insn but couldn't figure out how to ICE
and stringify an insn. I will have a look at this tomorrow. Did you have any
place in mind where to put/call something like this?
Cheers,
Stefan
