Messages in this thread | | | Date | Mon, 22 Apr 2013 14:29:05 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/2] lib: Add lz4 compressor module |
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On Mon, 22 Apr 2013 11:24:21 +0200 Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Mon, Apr 22, 2013 at 11:22 AM, Chanho Min <chanho.min@lge.com> wrote: > >>> +#define HTYPE const u8* > >>> + > >>> +#ifdef __BIG_ENDIAN > >>> +#define LZ4_NBCOMMONBYTES(val) (__builtin_clz(val) >> 3) > >>> +#else > >>> +#define LZ4_NBCOMMONBYTES(val) (__builtin_ctz(val) >> 3) > >>> +#endif > >> > >>It seems at least m68k and sparc don't have the __builtin_clz() functions: > >> > >>m68k-allmodconfig (http://kisskb.ellerman.id.au/kisskb/buildresult/8572593/): > >> > >>ERROR: "__clzsi2" [lib/lz4/lz4hc_compress.ko] undefined! > >>ERROR: "__clzsi2" [lib/lz4/lz4_compress.ko] undefined! > > > > gcc seems to define __builtin_clz as __clzsi2 in some architecture. > > But, kernel doesn't link libgcc.a. > > If kernel should use gcc's built-in function without libgcc.a, > > do we need to port __clzsi2 to 'arch/*/lib/*'? > > That's another option.
Without having seen the patch .... Yes, if we fix it this way then we also fix it for future callers of __builtin_clz().
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