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From: "kungfujesus06 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/108498] ppc64 big endian generates uninitialized reads with -fstore-merging
Date: Mon, 23 Jan 2023 15:18:28 +0000 [thread overview]
Message-ID: <bug-108498-4-K6IDIw8rYy@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108498-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108498
--- Comment #1 from Adam Stylinski <kungfujesus06 at gmail dot com> ---
I also should note this affects GCC 11.3, as well. The code being generated
via this optimization, while marginally shorter, seems to be rather suboptimal
in general. Here's what clang's emitting for the same sequence:
0000000000000930 <.emit_test>:
930: 3c a0 02 00 lis r5,512
934: 38 80 00 01 li r4,1
938: 88 e3 00 08 lbz r7,8(r3)
93c: 60 a5 ff 03 ori r5,r5,65283
940: 38 c0 02 01 li r6,513
944: f8 83 00 0c std r4,12(r3)
948: 38 80 00 02 li r4,2
94c: 78 a5 01 8a rldic r5,r5,32,6
950: f8 83 00 14 std r4,20(r3)
954: 38 80 00 00 li r4,0
958: 78 c6 d0 02 rotldi r6,r6,58
95c: 64 a5 00 01 oris r5,r5,1
960: f8 83 00 34 std r4,52(r3)
964: 38 80 00 1c li r4,28
968: 60 a5 02 03 ori r5,r5,515
96c: f8 c3 00 24 std r6,36(r3)
970: 54 e6 07 fe clrlwi r6,r7,31
974: 50 c4 07 b4 rlwimi r4,r6,0,30,26
978: f8 a3 00 00 std r5,0(r3)
97c: 3c a0 00 01 lis r5,1
980: 98 83 00 08 stb r4,8(r3)
984: 60 a4 02 03 ori r4,r5,515
988: 78 84 c5 c8 rldic r4,r4,24,23
98c: f8 83 00 3c std r4,60(r3)
990: 4e 80 00 20 blr
This bug is affecting the mesa project, so at least fixing this to emitting
correct code (if a little suboptimal) would go a long way.
next prev parent reply other threads:[~2023-01-23 15:18 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-23 14:18 [Bug c/108498] New: " kungfujesus06 at gmail dot com
2023-01-23 15:18 ` kungfujesus06 at gmail dot com [this message]
2023-01-23 15:20 ` [Bug middle-end/108498] " pinskia at gcc dot gnu.org
2023-01-23 15:22 ` kungfujesus06 at gmail dot com
2023-01-23 15:34 ` kungfujesus06 at gmail dot com
2023-01-23 15:38 ` rguenth at gcc dot gnu.org
2023-01-23 15:48 ` kungfujesus06 at gmail dot com
2023-01-23 15:51 ` kungfujesus06 at gmail dot com
2023-01-23 15:54 ` kungfujesus06 at gmail dot com
2023-01-23 17:39 ` pinskia at gcc dot gnu.org
2023-01-23 17:40 ` pinskia at gcc dot gnu.org
2023-01-23 17:42 ` kungfujesus06 at gmail dot com
2023-01-23 17:45 ` pinskia at gcc dot gnu.org
2023-01-23 17:51 ` [Bug tree-optimization/108498] " pinskia at gcc dot gnu.org
2023-01-23 17:51 ` kungfujesus06 at gmail dot com
2023-01-23 18:18 ` kungfujesus06 at gmail dot com
2023-01-23 19:04 ` jakub at gcc dot gnu.org
2023-01-24 12:20 ` [Bug tree-optimization/108498] [11/12/13 Regression] " jakub at gcc dot gnu.org
2023-01-24 12:55 ` jakub at gcc dot gnu.org
2023-01-24 15:35 ` jakub at gcc dot gnu.org
2023-01-24 16:09 ` jakub at gcc dot gnu.org
2023-01-24 16:48 ` ebotcazou at gcc dot gnu.org
2023-01-24 17:10 ` jakub at gcc dot gnu.org
2023-01-24 17:33 ` ebotcazou at gcc dot gnu.org
2023-01-24 17:46 ` jakub at gcc dot gnu.org
2023-01-25 9:51 ` cvs-commit at gcc dot gnu.org
2023-01-25 10:35 ` [Bug tree-optimization/108498] [11/12 " jakub at gcc dot gnu.org
2023-02-10 17:46 ` cvs-commit at gcc dot gnu.org
2023-02-10 18:00 ` [Bug tree-optimization/108498] [11 " jakub at gcc dot gnu.org
2023-05-02 20:13 ` cvs-commit at gcc dot gnu.org
2023-05-03 10:35 ` jakub at gcc dot gnu.org
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