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From: "aldyh at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109154] [13 regression] jump threading de-optimizes nested floating point comparisons
Date: Wed, 22 Mar 2023 10:20:53 +0000	[thread overview]
Message-ID: <bug-109154-4-t4QyE9YJwt@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109154-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109154

Aldy Hernandez <aldyh at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |amacleod at redhat dot com,
                   |                            |law at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org

--- Comment #4 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
(In reply to Tamar Christina from comment #3)
> Aldy, any thoughts here?

We need a "real" threading expert on this one, as the decision by ranger is
correct.  It looks like this is a profitability issue in the threader.

The problem can be seen with -O2 --param=threader-debug=all, on the threadfull1
dump:

The threaded path is:
path: 4->5->7 SUCCESS

ranger can fold the conditional in BB5:

    if (_1 < 1.0e+0)
      goto <bb 7>; [41.00%]
    else
      goto <bb 6>; [59.00%]

...because on entry to BB5 we know _1 < 0.0:

  <bb 3> [local count: 955630225]:
  _1 = (float) l_9;
  _2 = _1 < 0.0;
  zone1_15 = (int) _2;
  if (_1 < 0.0)
    goto <bb 4>; [41.00%]
  else
    goto <bb 5>; [59.00%]

  <bb 4> [local count: 391808389]:

  <bb 5> [local count: 955630225]:
  # iftmp.0_10 = PHI <zone1_15(4), 1(3)>
  fasten_main_natpro_chrg_init.2_3 = fasten_main_natpro_chrg_init;
  _4 = fasten_main_natpro_chrg_init.2_3 * iftmp.0_10;
  _5 = (float) _4;
  if (_1 < 1.0e+0)
    goto <bb 7>; [41.00%]
  else
    goto <bb 6>; [59.00%]

If this shouldn't be threaded because of a hot/cold issue, perhaps the code
goes in back_threader_profitability::profitable_path_p() where there's already
logic wrt hot blocks.

  parent reply	other threads:[~2023-03-22 10:20 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-16 11:57 [Bug tree-optimization/109154] New: [13 regression] aarch64 -mcpu=neoverse-v1 microbude performance regression pgodbole at nvidia dot com
2023-03-16 13:11 ` [Bug tree-optimization/109154] " tnfchris at gcc dot gnu.org
2023-03-16 14:58 ` [Bug target/109154] " rguenth at gcc dot gnu.org
2023-03-16 17:03 ` tnfchris at gcc dot gnu.org
2023-03-16 17:03 ` [Bug target/109154] [13 regression] jump threading with de-optimizes nested floating point comparisons tnfchris at gcc dot gnu.org
2023-03-22 10:20 ` aldyh at gcc dot gnu.org [this message]
2023-03-22 10:29 ` [Bug tree-optimization/109154] [13 regression] jump threading " avieira at gcc dot gnu.org
2023-03-22 12:22 ` rguenth at gcc dot gnu.org
2023-03-22 12:42 ` rguenth at gcc dot gnu.org
2023-03-22 13:11 ` aldyh at gcc dot gnu.org
2023-03-22 14:00 ` amacleod at redhat dot com
2023-03-22 14:39 ` aldyh at gcc dot gnu.org
2023-03-27  8:09 ` rguenth at gcc dot gnu.org
2023-03-27  9:30 ` jakub at gcc dot gnu.org
2023-03-27  9:42 ` aldyh at gcc dot gnu.org
2023-03-27  9:44 ` jakub at gcc dot gnu.org
2023-03-27 10:18 ` rguenther at suse dot de
2023-03-27 10:40 ` jakub at gcc dot gnu.org
2023-03-27 10:44 ` jakub at gcc dot gnu.org
2023-03-27 10:54 ` rguenth at gcc dot gnu.org
2023-03-27 10:56 ` jakub at gcc dot gnu.org
2023-03-27 10:59 ` jakub at gcc dot gnu.org
2023-03-27 17:07 ` jakub at gcc dot gnu.org
2023-03-28  8:33 ` rguenth at gcc dot gnu.org
2023-03-28  9:01 ` cvs-commit at gcc dot gnu.org
2023-03-28 10:07 ` tnfchris at gcc dot gnu.org
2023-03-28 10:08 ` tnfchris at gcc dot gnu.org
2023-03-28 12:18 ` jakub at gcc dot gnu.org
2023-03-28 12:25 ` rguenth at gcc dot gnu.org
2023-03-28 12:42 ` rguenth at gcc dot gnu.org
2023-03-28 13:19 ` rguenth at gcc dot gnu.org
2023-03-28 13:44 ` jakub at gcc dot gnu.org
2023-03-28 13:52 ` jakub at gcc dot gnu.org
2023-03-28 15:31 ` amacleod at redhat dot com
2023-03-28 15:40 ` jakub at gcc dot gnu.org
2023-03-28 15:53 ` amacleod at redhat dot com
2023-03-28 15:58 ` jakub at gcc dot gnu.org
2023-03-28 16:42 ` amacleod at redhat dot com
2023-03-28 21:12 ` amacleod at redhat dot com
2023-03-29  6:33 ` cvs-commit at gcc dot gnu.org
2023-03-29  6:38 ` rguenth at gcc dot gnu.org
2023-03-29 22:41 ` amacleod at redhat dot com
2023-03-30 18:17 ` cvs-commit at gcc dot gnu.org
2023-04-05  9:28 ` tnfchris at gcc dot gnu.org
2023-04-05  9:34 ` ktkachov at gcc dot gnu.org
2023-04-11  9:36 ` rguenth at gcc dot gnu.org
2023-04-13 16:54 ` jakub at gcc dot gnu.org
2023-04-13 17:25 ` rguenther at suse dot de
2023-04-13 17:29 ` jakub at gcc dot gnu.org
2023-04-14 18:10 ` jakub at gcc dot gnu.org
2023-04-14 18:14 ` jakub at gcc dot gnu.org
2023-04-14 18:22 ` jakub at gcc dot gnu.org
2023-04-14 19:09 ` jakub at gcc dot gnu.org
2023-04-15 10:10 ` cvs-commit at gcc dot gnu.org
2023-04-17 11:07 ` jakub at gcc dot gnu.org
2023-04-25 18:32 ` [Bug tree-optimization/109154] [13/14 " tnfchris at gcc dot gnu.org
2023-04-25 18:34 ` jakub at gcc dot gnu.org
2023-04-26  6:58 ` rguenth at gcc dot gnu.org
2023-04-26  9:43 ` tnfchris at gcc dot gnu.org
2023-04-26 10:07 ` jakub at gcc dot gnu.org
2023-07-07 18:10 ` tnfchris at gcc dot gnu.org
2023-07-10  7:15 ` rguenth at gcc dot gnu.org
2023-07-10 10:33 ` tnfchris at gcc dot gnu.org
2023-07-10 10:46 ` rguenth at gcc dot gnu.org
2023-07-10 11:02 ` tnfchris at gcc dot gnu.org
2023-07-10 11:27 ` rguenth at gcc dot gnu.org
2023-07-10 11:49 ` tnfchris at gcc dot gnu.org
2023-07-14 10:22 ` cvs-commit at gcc dot gnu.org
2023-07-14 10:22 ` cvs-commit at gcc dot gnu.org
2023-07-27  9:25 ` rguenth at gcc dot gnu.org
2023-10-02 10:53 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:54 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:54 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:54 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:55 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:25 ` [Bug tree-optimization/109154] [13 " tnfchris at gcc dot gnu.org

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