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From: "linkw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/106069] [12/13 Regression] wrong code with -O -fno-tree-forwprop -maltivec on ppc64le
Date: Wed, 03 Aug 2022 08:06:46 +0000 [thread overview]
Message-ID: <bug-106069-4-Kl9jzwAfvN@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106069-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106069
--- Comment #21 from Kewen Lin <linkw at gcc dot gnu.org> ---
I didn't look into this in details, but something in the culprit commit caught
my eyes, take altivec_vmrghh as example:
Before the patch, the pattern
[(set (match_operand:V8HI 0 "register_operand" "=v")
(vec_select:V8HI
(vec_concat:V16HI
(match_operand:V8HI 1 "register_operand" "v")
(match_operand:V8HI 2 "register_operand" "v"))
(parallel [(const_int 0) (const_int 8)
(const_int 1) (const_int 9)
(const_int 2) (const_int 10)
(const_int 3) (const_int 11)])))]
can match vmrghh on BE while vmrglh on LE. It indicates this pattern has
different semantic from underlying instruction perspectives.
After the patch, this pattern only matches vmrghh.
IMHO, this part has semantic change before and after the patch. The code before
the patch looks more reasonable to me, since the pattern can have different
meanings on BE and LE (underlying behavior).
next prev parent reply other threads:[~2022-08-03 8:06 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-23 23:13 [Bug target/106069] New: " mpolacek at gcc dot gnu.org
2022-06-23 23:15 ` [Bug target/106069] [12/13 Regression] " mpolacek at gcc dot gnu.org
2022-06-23 23:18 ` mpolacek at gcc dot gnu.org
2022-06-24 3:25 ` luoxhu at gcc dot gnu.org
2022-06-24 13:03 ` mpolacek at gcc dot gnu.org
2022-06-30 8:13 ` luoxhu at gcc dot gnu.org
2022-06-30 8:15 ` luoxhu at gcc dot gnu.org
2022-06-30 17:32 ` segher at gcc dot gnu.org
2022-06-30 17:34 ` segher at gcc dot gnu.org
2022-07-01 1:52 ` luoxhu at gcc dot gnu.org
2022-07-25 15:54 ` rguenth at gcc dot gnu.org
2022-07-25 20:16 ` segher at gcc dot gnu.org
2022-07-25 20:18 ` segher at gcc dot gnu.org
2022-07-26 3:34 ` luoxhu at gcc dot gnu.org
2022-07-26 3:34 ` luoxhu at gcc dot gnu.org
2022-07-26 3:35 ` luoxhu at gcc dot gnu.org
2022-07-26 3:53 ` luoxhu at gcc dot gnu.org
2022-07-26 6:28 ` luoxhu at gcc dot gnu.org
2022-07-29 11:10 ` rguenth at gcc dot gnu.org
2022-07-29 11:21 ` rguenth at gcc dot gnu.org
2022-08-03 6:10 ` yinyuefengyi at gmail dot com
2022-08-03 6:38 ` yinyuefengyi at gmail dot com
2022-08-03 8:06 ` linkw at gcc dot gnu.org [this message]
2022-08-03 8:24 ` rguenther at suse dot de
2022-08-03 8:50 ` linkw at gcc dot gnu.org
2022-08-03 8:59 ` rguenth at gcc dot gnu.org
2022-08-03 9:20 ` rsandifo at gcc dot gnu.org
2022-08-03 9:25 ` rsandifo at gcc dot gnu.org
2022-08-03 18:01 ` segher at gcc dot gnu.org
2022-08-03 18:06 ` segher at gcc dot gnu.org
2022-08-04 9:17 ` rsandifo at gcc dot gnu.org
2022-08-04 9:21 ` rearnsha at gcc dot gnu.org
2022-08-04 9:59 ` yinyuefengyi at gmail dot com
2022-08-04 10:01 ` yinyuefengyi at gmail dot com
2023-01-16 18:00 ` jakub at gcc dot gnu.org
2023-03-24 16:16 ` jakub at gcc dot gnu.org
2023-03-24 17:01 ` bergner at gcc dot gnu.org
2023-03-31 2:57 ` yinyuefengyi at gmail dot com
2023-05-08 12:24 ` [Bug target/106069] [12/13/14 " rguenth at gcc dot gnu.org
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