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Doing hweight16() and checking whether the lsb is set is functionally equivalent to what bitwise_xor_bits() does. In addition, it results in better generated code as before gcc would inline the function 4 times. With hweight16(), the resulting code boils down to 2 instructions - POPCNT and AND, and all relevant CPUs support POPCNT. An alternative would have been to use the __builtin_parity() function provided by both Clang/GCC, however under some circumstances the compiler can choose not to inline it but generate a library call which is unsupported in the kernel. No functional changes. [ bp: Massage commit message. ] Signed-off-by: Nikolay Borisov <nik.borisov@suse.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/20251124142517.1708451-1-nik.borisov@suse.com
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 reStructuredText 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.