On Wed, 9 Aug 2023, Jakub Jelinek wrote:
> On Wed, Aug 09, 2023 at 01:06:22PM -0700, Andrew Pinski wrote:
> > That was my next thought, returning NULL from
> > single_non_singleton_phi_for_edges if it would return a virtual OP
> > might be better even.
> > Either version of these patches are ok with me (though I am not the
> > maintainer here).
>
> In patch form that would be (but so far untested):
LGTM
> 2023-08-09 <ja...@redhat.com>
>
> PR c/102989
> * tree-ssa-phiopt.cc (single_non_singleton_phi_for_edges): Never
> return virtual phis and return NULL if there is a virtual phi
> where the arguments from E0 and E1 edges aren't equal.
>
> --- gcc/tree-ssa-phiopt.cc.jj 2023-08-09 22:08:07.974563266 +0200
> +++ gcc/tree-ssa-phiopt.cc 2023-08-09 22:11:37.291517911 +0200
> @@ -63,7 +63,13 @@ single_non_singleton_phi_for_edges (gimp
> gimple_stmt_iterator i;
> gphi *phi = NULL;
> if (gimple_seq_singleton_p (seq))
> - return as_a <gphi *> (gsi_stmt (gsi_start (seq)));
> + {
> + phi = as_a <gphi *> (gsi_stmt (gsi_start (seq)));
> + /* Never return virtual phis. */
> + if (virtual_operand_p (gimple_phi_result (phi)))
> + return NULL;
> + return phi;
> + }
> for (i = gsi_start (seq); !gsi_end_p (i); gsi_next (&i))
> {
> gphi *p = as_a <gphi *> (gsi_stmt (i));
> @@ -72,6 +78,10 @@ single_non_singleton_phi_for_edges (gimp
> gimple_phi_arg_def (p, e1->dest_idx)))
> continue;
>
> + /* Punt on virtual phis with different arguments from the edges. */
> + if (virtual_operand_p (gimple_phi_result (p)))
> + return NULL;
> +
> /* If we already have a PHI that has the two edge arguments are
> different, then return it is not a singleton for these PHIs. */
> if (phi)
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
