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From: "deller at gmx dot de" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/102162] Byte-wise access optimized away at -O1 and
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Date: Thu, 02 Sep 2021 09:41:12 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102162

--- 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:=20
[deller@ls3530 linux-2.6]$ grep get_unaligned lib/decompress*
lib/decompress_unlz4.c: size_t out_len =3D get_unaligned_le32(input + in_le=
n);
lib/decompress_unlz4.c: chunksize =3D get_unaligned_le32(inp);
lib/decompress_unlz4.c:         chunksize =3D get_unaligned_le32(inp);
lib/decompress_unlzo.c: version =3D get_unaligned_be16(parse);
lib/decompress_unlzo.c: if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
lib/decompress_unlzo.c:         dst_len =3D get_unaligned_be32(in_buf);
lib/decompress_unlzo.c:         src_len =3D 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=