Ping.
On Wed, Sep 07, 2022 at 04:20:25PM +0200, Stefan Schulze Frielinghaus wrote:
> Whenever a new cselib value is created check whether a smaller value
> exists which is contained in the bigger one. If so add a subreg
> relation to locs of the smaller one.
>
> gcc/ChangeLog:
>
> * cselib.cc (new_cselib_val): Keep track of further subvalue
> relations.
> ---
> gcc/cselib.cc | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/gcc/cselib.cc b/gcc/cselib.cc
> index 6a5609786fa..9b582e5d3d6 100644
> --- a/gcc/cselib.cc
> +++ b/gcc/cselib.cc
> @@ -1569,6 +1569,26 @@ new_cselib_val (unsigned int hash, machine_mode mode,
> rtx x)
> e->locs = 0;
> e->next_containing_mem = 0;
>
> + scalar_int_mode int_mode;
> + if (REG_P (x) && is_int_mode (mode, &int_mode)
> + && REG_VALUES (REGNO (x)) != NULL
> + && (!cselib_current_insn || !DEBUG_INSN_P (cselib_current_insn)))
> + {
> + rtx copy = shallow_copy_rtx (x);
> + scalar_int_mode narrow_mode_iter;
> + FOR_EACH_MODE_UNTIL (narrow_mode_iter, int_mode)
> + {
> + PUT_MODE_RAW (copy, narrow_mode_iter);
> + cselib_val *v = cselib_lookup (copy, narrow_mode_iter, 0, VOIDmode);
> + if (v)
> + {
> + rtx sub = lowpart_subreg (narrow_mode_iter, e->val_rtx, int_mode);
> + if (sub)
> + new_elt_loc_list (v, sub);
> + }
> + }
> + }
> +
> if (dump_file && (dump_flags & TDF_CSELIB))
> {
> fprintf (dump_file, "cselib value %u:%u ", e->uid, hash);
> --
> 2.37.2
>
