public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/94727] [10 Regression] GCC produces incorrect code with -O3 since r10-5071-g02d895504cc59be0
Date: Thu, 23 Apr 2020 07:02:42 +0000 [thread overview]
Message-ID: <bug-94727-4-vC45TXF5al@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-94727-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94727
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #2)
> test() is basic-block vectorized on the c-loop body which has the d- and
> e-loops
> completely unrolled. We create some weird
>
> mask__84.17_18 = vect_cst__94 < vect_cst__20;
> vect_patt_266.18_6 = VEC_COND_EXPR <mask__84.17_18, vect_cst__16,
> vect_cst__15>;
>
> where vect_cst__94 and vect_cst__20 look like
>
> { var_3.1_42 ? -1 : 0, var_3.1_42 ? -1 : 0, ...
>
> or even
>
> { _272 ? -1 : 0, ...
>
> with
>
> _272 = _271 < var_11.0_40
>
> so the vectorization is quite imperfect, mainly due to
>
> t1.C:9:32: note: ==> examining statement: _85 = var_11.0_40 > _86;
> t1.C:12:69: missed: not vectorized: relevant stmt not supported: _85 =
> var_11.0_40 > _86;
> t1.C:9:32: note: Building vector operands from scalars instead
>
> that doesn't yet explain what goes wrong here.
If you change the e loop iteration to stop at e < 16 the testcase is not
miscompiled, so somehow the
t1.C:9:20: missed: Build SLP failed: incompatible vector types for:
arr_42[a_26][0][c_11][0][16] = _44;
t1.C:9:20: note: old vector type: vector(2) long long int
t1.C:9:20: note: new vector type: vector(1) long long int
might be a relevant factor. Leaving to Richard.
next prev parent reply other threads:[~2020-04-23 7:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-23 5:14 [Bug tree-optimization/94727] New: GCC produces incorrect code with -O3 vsevolod.livinskij at frtk dot ru
2020-04-23 5:35 ` [Bug tree-optimization/94727] [10 Regression] GCC produces incorrect code with -O3 since r10-5071-g02d895504cc59be0 marxin at gcc dot gnu.org
2020-04-23 6:44 ` rguenth at gcc dot gnu.org
2020-04-23 7:02 ` rguenth at gcc dot gnu.org [this message]
2020-04-23 7:34 ` rsandifo at gcc dot gnu.org
2020-04-23 10:26 ` rsandifo at gcc dot gnu.org
2020-04-23 12:35 ` rguenth at gcc dot gnu.org
2020-04-23 13:02 ` rsandifo at gcc dot gnu.org
2020-04-23 14:45 ` cvs-commit at gcc dot gnu.org
2020-04-23 14:48 ` rsandifo at gcc dot gnu.org
2020-04-28 7:04 ` cvs-commit at gcc dot gnu.org
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bug-94727-4-vC45TXF5al@http.gcc.gnu.org/bugzilla/ \
--to=gcc-bugzilla@gcc.gnu.org \
--cc=gcc-bugs@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).