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Nick Desaulniers
3dae5c43ba
Micro-optimize the bitops code some more, similar to commits:fdb6649ab7("x86/asm/bitops: Use __builtin_ctzl() to evaluate constant expressions")2fcff790dc("powerpc: Use builtin functions for fls()/__fls()/fls64()") From a recent discussion, I noticed that x86 is lacking an optimization that appears in arch/powerpc/include/asm/bitops.h related to constant folding. If you add a BUILD_BUG_ON(__builtin_constant_p(param)) to these functions, you'll find that there were cases where the use of inline asm pessimized the compiler's ability to perform constant folding resulting in runtime calculation of a value that could have been computed at compile time. Signed-off-by: Nick Desaulniers <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: https://lore.kernel.org/r/[email protected]
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.