On Tue, 24 Mar 2020, Jakub Jelinek wrote:
> Hi!
>
> The following testcase shows -fcompare-debug bugs in ifcvt_local_dce,
> where the decisions what statements are needed is based also on debug stmt
> operands, which is wrong.
> So, this patch makes sure to never add debug stmt to the worklist, or never
> add an assign to worklist just because it is used in a debug stmt in another
> bb.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
> 2020-03-24 Jakub Jelinek <ja...@redhat.com>
>
> PR debug/94283
> * tree-if-conv.c (ifcvt_local_dce): For gimple debug stmts, just set
> GF_PLF_2, but don't add them to worklist. Don't add an assigment to
> worklist or set GF_PLF_2 just because it is used in a debug stmt in
> another bb. Formatting improvements.
>
> * gcc.target/i386/pr94283.c: New test.
>
> --- gcc/tree-if-conv.c.jj 2020-01-12 11:54:38.495381997 +0100
> +++ gcc/tree-if-conv.c 2020-03-23 17:13:13.823724294 +0100
> @@ -2917,9 +2917,12 @@ ifcvt_local_dce (class loop *loop)
> for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
> {
> stmt = gsi_stmt (gsi);
> - if (gimple_store_p (stmt)
> - || gimple_assign_load_p (stmt)
> - || is_gimple_debug (stmt))
> + if (is_gimple_debug (stmt))
> + {
> + gimple_set_plf (stmt, GF_PLF_2, true);
> + continue;
> + }
> + if (gimple_store_p (stmt) || gimple_assign_load_p (stmt))
> {
> gimple_set_plf (stmt, GF_PLF_2, true);
> worklist.safe_push (stmt);
> @@ -2940,7 +2943,7 @@ ifcvt_local_dce (class loop *loop)
> FOR_EACH_IMM_USE_FAST (use_p, imm_iter, lhs)
> {
> stmt1 = USE_STMT (use_p);
> - if (gimple_bb (stmt1) != bb)
> + if (!is_gimple_debug (stmt1) && gimple_bb (stmt1) != bb)
> {
> gimple_set_plf (stmt, GF_PLF_2, true);
> worklist.safe_push (stmt);
> @@ -2963,8 +2966,7 @@ ifcvt_local_dce (class loop *loop)
> if (TREE_CODE (use) != SSA_NAME)
> continue;
> stmt1 = SSA_NAME_DEF_STMT (use);
> - if (gimple_bb (stmt1) != bb
> - || gimple_plf (stmt1, GF_PLF_2))
> + if (gimple_bb (stmt1) != bb || gimple_plf (stmt1, GF_PLF_2))
> continue;
> gimple_set_plf (stmt1, GF_PLF_2, true);
> worklist.safe_push (stmt1);
> --- gcc/testsuite/gcc.target/i386/pr94283.c.jj 2020-03-23
> 17:16:50.324494226 +0100
> +++ gcc/testsuite/gcc.target/i386/pr94283.c 2020-03-23 17:16:42.238614863
> +0100
> @@ -0,0 +1,5 @@
> +/* PR debug/94283 */
> +/* { dg-do compile } */
> +/* { dg-options "-O3 -fcompare-debug -mavx2" } */
> +
> +#include "../../gcc.dg/fold-bopcond-1.c"
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
