Arnd, Please pull the following branch: git://git.linaro.org/people/nicolas.pitre/linux div64 This contains those patches I've initially posted here: https://lkml.org/lkml/2015/11/2/715 Only changes to those posted patches are cosmetic improvements such as the use of ilog2() replacing the custom __div64_ffs(). Exposure in linux-next would be a good thing. I also included fixes for a couple do_div() misuses that an allyesconfig build turned up after switching ARM to the generic do_div() code. Those patches have been posted separately and addressed to relevant maintainers. They are included here until/unless those maintainers include those patches in their tree. Original cover letter: This is a generalization of the optimization I produced for ARM a decade ago to turn constant divisors into a multiplication by the divisor reciprocal. Turns out that after all those years gcc is still not optimizing things on its own for that case. This has important performance benefits as discussed in this thread: https://lkml.org/lkml/2015/10/28/851 This series brings the formerly ARM-only optimization to all 32-bit architectures using C code by default. The possibility for the actual multiplication to be implemented in assembly is provided in order to get optimal code. The ARM version can be used as an example implementation for other interested architectures to implement. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
