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Nathan Chancellor authored
clang does not support -falign-jumps and only recently gained support
for -falign-loops. When one of the configuration options that adds these
flags is enabled, clang warns and all cc-{disable-warning,option} that
follow fail because -Werror gets added to test for the presence of this
warning:

clang-14: warning: optimization flag '-falign-jumps=0' is not supported
[-Wignored-optimization-argument]

To resolve this, add a couple of cc-option calls when building with
clang; gcc has supported these options since 3.2 so there is no point in
testing for their support. -falign-functions was implemented in clang-7,
-falign-loops was implemented in clang-14, and -falign-jumps has not
been implemented yet.

Link: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/
Link: https://lore.kernel.org/r/20210824022640.2170859-2-nathan@kernel.org/


Reported-by: default avatarkernel test robot <lkp@intel.com>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Acked-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarNathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
7fa6a274
Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.