Re: Undefined reference to __builtin_ctzll
- From
Erik Faye-Lund <kusmabite@gmail.com>
- Date
- Aug 13, 2014, 10:15 UTC
- Message-ID
- <CABPQNSZw4vwhF8m+TWrbuOSaV5ycRGm1oeCu42j96_T+f3xtTg@mail.gmail.com>
- In-Reply-To
- <CAAC8vw4EzaEM13TWzEW9QUuc-qdZFhPfEA9z1=KjCE0Brzotjg@mail.gmail.com>
On Wed, Aug 13, 2014 at 10:36 AM, Радослав Йовчев <radoslav.tm@gmail.com> wrote:
Show 26 quoted lines
> Dear GIT community,
>
>
> I found myself in situation where I had to install GIT on Debian 3.1
> sarge. It comes with GCC 3.3.5. I tried to built from source but the
> libgcc was not providing the ctzll function, thus I decided to put an
> implementation.
>
>
> I do not know how to post and do a nice patch (and whether somebody
> will care), but I guess, for reference I can post my solution. Just
> appended in compat/strlcpy.c the following:
>
>
> int __builtin_ctzll (long long x)
> {
> int i;
> for (i = 0; i < 8 * sizeof (long long); ++i)
> if (x & ((long long) 1 << i))
> break;
> return i;
> }
>
>
> I guess that some ifdef macro can be used to detect compiler version
> or missing __builtin_ctzll.It seems __builtin_ctzll is only available in GCC 3.4.0 and beyond, so I think a better fix is something like this:
diff --git a/ewah/ewok.h b/ewah/ewok.h index 43adeb5..2700fa3 100644 --- a/ewah/ewok.h +++ b/ewah/ewok.h @@ -47,7 +47,7 @@ static inline uint32_t ewah_bit_popcount64(uint64_t x) return (x * 0x0101010101010101ULL) >> 56; } -#ifdef __GNUC__ +#if (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || __GNUC__ > 3 #define ewah_bit_ctz64(x) __builtin_ctzll(x) #else static inline int ewah_bit_ctz64(uint64_t x)