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From: "deller at gmx dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/102162] Byte-wise access optimized away at -O1 and above
Date: Thu, 02 Sep 2021 09:41:12 +0000 [thread overview]
Message-ID: <bug-102162-4-8CPPzdMIAb@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102162-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102162
--- Comment #28 from deller at gmx dot de ---
Arnd,
there are various calls to the get_unaligned_X() functions in all kernel
bootloaders, specifically in the kernel decompression routines:
[deller@ls3530 linux-2.6]$ grep get_unaligned lib/decompress*
lib/decompress_unlz4.c: size_t out_len = get_unaligned_le32(input + in_len);
lib/decompress_unlz4.c: chunksize = get_unaligned_le32(inp);
lib/decompress_unlz4.c: chunksize = get_unaligned_le32(inp);
lib/decompress_unlzo.c: version = get_unaligned_be16(parse);
lib/decompress_unlzo.c: if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
lib/decompress_unlzo.c: dst_len = get_unaligned_be32(in_buf);
lib/decompress_unlzo.c: src_len = get_unaligned_be32(in_buf);
So sadly it's not possible to work around that cases with linker scripts,
because they work on externally generated compressed files (kernel code) for
which the specs of the compressed files can't be changed.
Same for the output_len variable - externally linked in directly behind the
code and not (easily?) changeable.
Helge
next prev parent reply other threads:[~2021-09-02 9:41 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 16:52 [Bug tree-optimization/102162] New: " danglin at gcc dot gnu.org
2021-09-01 18:52 ` [Bug tree-optimization/102162] " danglin at gcc dot gnu.org
2021-09-01 20:14 ` arnd at linaro dot org
2021-09-01 20:52 ` deller at gmx dot de
2021-09-01 20:56 ` dave.anglin at bell dot net
2021-09-01 21:08 ` dave.anglin at bell dot net
2021-09-01 21:15 ` deller at gmx dot de
2021-09-01 21:19 ` dave.anglin at bell dot net
2021-09-01 21:25 ` deller at gmx dot de
2021-09-01 21:29 ` deller at gmx dot de
2021-09-01 21:48 ` pinskia at gcc dot gnu.org
2021-09-01 21:51 ` [Bug middle-end/102162] " pinskia at gcc dot gnu.org
2021-09-01 21:52 ` pinskia at gcc dot gnu.org
2021-09-01 22:35 ` dave.anglin at bell dot net
2021-09-01 22:46 ` dave.anglin at bell dot net
2021-09-01 22:56 ` pinskia at gcc dot gnu.org
2021-09-01 23:19 ` pinskia at gcc dot gnu.org
2021-09-01 23:21 ` pinskia at gcc dot gnu.org
2021-09-01 23:29 ` pinskia at gcc dot gnu.org
2021-09-01 23:45 ` pinskia at gcc dot gnu.org
2021-09-01 23:55 ` pinskia at gcc dot gnu.org
2021-09-02 0:02 ` dave.anglin at bell dot net
2021-09-02 0:19 ` pinskia at gcc dot gnu.org
2021-09-02 0:23 ` pinskia at gcc dot gnu.org
2021-09-02 0:47 ` dave.anglin at bell dot net
2021-09-02 0:49 ` pinskia at gcc dot gnu.org
2021-09-02 3:33 ` pinskia at gcc dot gnu.org
2021-09-02 7:12 ` rguenth at gcc dot gnu.org
2021-09-02 9:01 ` arnd at linaro dot org
2021-09-02 9:41 ` deller at gmx dot de [this message]
2021-09-02 9:52 ` pinskia at gcc dot gnu.org
2021-09-02 13:59 ` deller at gmx dot de
2021-09-02 14:00 ` deller at gmx dot de
2021-09-03 23:25 ` deller at gmx dot de
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