On Tue, 24 Mar 2020, Jakub Jelinek wrote:
> On Tue, Mar 24, 2020 at 10:59:19AM +0100, Richard Biener wrote:
> > Likely
> >
> > /* Delete dead statements. */
> > gsi = gsi_start_bb (bb);
> > while (!gsi_end_p (gsi))
> > {
> >
> > needs to instead work back-to-front for debug stmt adjustment to work
>
> Indeed, that seems to work. Ok for trunk if it passes bootstrap/regtest?
OK.
> 2020-03-24 Richard Biener <rguent...@suse.de>
> Jakub Jelinek <ja...@redhat.com>
>
> PR debug/94283
> * tree-if-conv.c (ifcvt_local_dce): Delete dead statements backwards.
>
> * gcc.dg/pr94283.c: New test.
>
> --- gcc/tree-if-conv.c.jj 2020-03-24 09:34:35.152087914 +0100
> +++ gcc/tree-if-conv.c 2020-03-24 11:13:41.179903247 +0100
> @@ -2973,9 +2973,11 @@ ifcvt_local_dce (class loop *loop)
> }
> }
> /* Delete dead statements. */
> - gsi = gsi_start_bb (bb);
> + gsi = gsi_last_bb (bb);
> while (!gsi_end_p (gsi))
> {
> + gimple_stmt_iterator gsiprev = gsi;
> + gsi_prev (&gsiprev);
> stmt = gsi_stmt (gsi);
> if (gimple_store_p (stmt))
> {
> @@ -2986,14 +2988,13 @@ ifcvt_local_dce (class loop *loop)
> if (dse_classify_store (&write, stmt, false, NULL, NULL, latch_vdef)
> == DSE_STORE_DEAD)
> delete_dead_or_redundant_assignment (&gsi, "dead");
> - else
> - gsi_next (&gsi);
> + gsi = gsiprev;
> continue;
> }
>
> if (gimple_plf (stmt, GF_PLF_2))
> {
> - gsi_next (&gsi);
> + gsi = gsiprev;
> continue;
> }
> if (dump_file && (dump_flags & TDF_DETAILS))
> @@ -3003,6 +3004,7 @@ ifcvt_local_dce (class loop *loop)
> }
> gsi_remove (&gsi, true);
> release_defs (stmt);
> + gsi = gsiprev;
> }
> }
>
> --- gcc/testsuite/gcc.dg/pr94283.c.jj 2020-03-24 11:15:35.782163250 +0100
> +++ gcc/testsuite/gcc.dg/pr94283.c 2020-03-24 11:16:37.909219978 +0100
> @@ -0,0 +1,16 @@
> +/* PR debug/94283 */
> +/* { dg-do compile } */
> +/* { dg-options "-O3 -fno-tree-dce -fcompare-debug" } */
> +
> +void
> +foo (int *n)
> +{
> + for (int i = 0; i < 32; i++)
> + {
> + int x = 0;
> + x++;
> + if (i & 4)
> + x++;
> + x++;
> + }
> +}
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
