On Sun, Sep 13, 2015 at 04:33:39AM +0200, Sedat Dilek wrote: > > It looks like an inline-optimization bug in CLANG when the compiler's > > optimization-level is higher than -O2.
> > [1] > > http://lists.linuxfoundation.org/pipermail/llvmlinux/2015-September/001355.html > > After some discussion on #llvm it turned out to be a known issue in LLVMLinux! > > Unfortunately, an existing patch [1] got archived which is still > required to build x86_64 correctly. > [1] > http://git.linuxfoundation.org/?p=llvmlinux.git;a=blob_plain;f=arch/x86_64/patches/ARCHIVE/0029-Fix-ARCH_HWEIGHT-for-compilation-with-clang.patch;hb=HEAD As long as LLVM cannot do things like that and requires full function calls I cannot see it being a sensible compiler to use from a performance POV. There's a fairly large difference between an inline POPCNT instruction and a full out-of-line function call. /me goes back to ignoring LLVM for the time being. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
