[Bug rtl-optimization/64815] ICE caused by volatile_refs_p doesn't skip NULL operand

["pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64815

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Terry Guo from comment #2)
> (In reply to Andrew Pinski from comment #1)
> > I don't think you need to call volatile_refs_p on the notes part of the
> > instruciton.
> 
> The volatile_refs_p works in a recursive way which makes itself to scan the
> notes part. I just call volatile_refs_p to the insn.
> 
> Do you mean I should update volatile_refs_p to avoid recursively scanning
> the notes part of the insn?

Oh you should be using volatile_refs_p on the insn but only the set; maybe even
just the lhs or rhs of the set.

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Terry Guo from comment #2)
> (In reply to Andrew Pinski from comment #1)
> > I don't think you need to call volatile_refs_p on the notes part of the
> > instruciton.
> 
> The volatile_refs_p works in a recursive way which makes itself to scan the
> notes part. I just call volatile_refs_p to the insn.
> 
> Do you mean I should update volatile_refs_p to avoid recursively scanning
> the notes part of the insn?

Oh you should be using volatile_refs_p on the insn but only the set.

dse.c:      || volatile_refs_p (PATTERN (insn))