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From: "rdapp at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/111760] risc-v regression: COND_LEN_* incorrect fold/simplify in middle-end
Date: Tue, 10 Oct 2023 21:02:53 +0000	[thread overview]
Message-ID: <bug-111760-4-BITVjVtD5C@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-111760-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111760

Robin Dapp <rdapp at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rdapp at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org

--- Comment #2 from Robin Dapp <rdapp at gcc dot gnu.org> ---
https://gcc.gnu.org/pipermail/gcc-patches/2023-September/629904.html

prevents the wrong code but still leaves us with a redundant negation (and it
is not the only missed optimization of that kind):

  vect_neg_xi_14.4_23 = -vect_xi_13.3_22;
  vect_res_2.5_24 = .COND_LEN_ADD ({ -1, ... }, vect_res_1.0_17,
vect_neg_xi_14.4_23, vect_res_1.0_17, _29, 0);

That's because my "hackaround" doesn't recognize a valueized sequence
_30 = vect_res_1.0_17 - vect_xi_13.3_22;

Of course I could (reverse valueize) recognize that again and convert it to a
COND_LEN... but that doesn't seem elegant at all.  There must be a simpler way
that I'm missing entirely right now.  That said, converting the last statement
of such a sequence should be sufficient?

  parent reply	other threads:[~2023-10-10 21:02 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-10 14:29 [Bug c/111760] New: " juzhe.zhong at rivai dot ai
2023-10-10 17:47 ` [Bug c/111760] " pinskia at gcc dot gnu.org
2023-10-10 21:02 ` rdapp at gcc dot gnu.org [this message]
2023-10-10 21:58 ` [Bug tree-optimization/111760] " juzhe.zhong at rivai dot ai
2023-10-10 22:04 ` pinskia at gcc dot gnu.org
2023-10-10 22:08 ` juzhe.zhong at rivai dot ai
2023-10-11  6:47 ` rdapp at gcc dot gnu.org
2023-10-11  8:36 ` rguenth at gcc dot gnu.org
2023-11-06 11:27 ` cvs-commit at gcc dot gnu.org
2023-11-07 23:39 ` juzhe.zhong at rivai dot ai

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