On Fri, May 31, 2019 at 01:06:13PM -0700, Nick Desaulniers wrote: > On Fri, May 31, 2019 at 12:21 PM Arnd Bergmann <a...@arndb.de> wrote: > > clang, I would suggest dropping your patch then, and instead adding > > I disagree. The minimum version of gcc required to build the kernel > is 4.6, so the comment about older versions of gcc is irrelevant and > should be removed. > > Nathan's -Rpass warnings are warning that vectorization was not > calculated to be profitable **for 1 of the 4 functions** by LLVM. > Surely we wouldn't disable NEON opts for XOR because 1 of 4 was not > vectorized?
Well I kept it short but clang warns that all of the loops are not profitable. However, the config option for xor-neon.c is CONFIG_XOR_BLOCKS, which also controls the arm64 implementation. We wouldn't want to disable it for clang altogether if it works on arm64 fine. If it turns out to be broken for both, I suppose I would be okay with disabling CONFIG_XOR_BLOCKS for clang but it should be done in a separate patch as this one should be applied regardless of clang working or not (because this warning will appear again when clang is fixed). Cheers, Nathan
