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| author | Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> | 2023-08-25 13:30:58 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2024-02-01 09:31:33 -0300 |
| commit | ae4b8d6a0e0dc502e3d8307474a2e5691b7434da (patch) | |
| tree | 8e8d958ebb90b9edec3847a53364edb32a2314a3 /string | |
| parent | 26d01172f5c3f3b912ecf21ebb911eb5351bba4d (diff) | |
| download | glibc-ae4b8d6a0e0dc502e3d8307474a2e5691b7434da.tar.gz glibc-ae4b8d6a0e0dc502e3d8307474a2e5691b7434da.tar.xz glibc-ae4b8d6a0e0dc502e3d8307474a2e5691b7434da.zip | |
string: Use builtins for ffs and ffsll
It allows to remove a lot of arch-specific implementations. Checked on x86_64, aarch64, powerpc64. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'string')
| -rw-r--r-- | string/ffs.c | 6 | ||||
| -rw-r--r-- | string/ffsll.c | 10 |
2 files changed, 13 insertions, 3 deletions
diff --git a/string/ffs.c b/string/ffs.c index 6a05ef8386..760c2bdd8d 100644 --- a/string/ffs.c +++ b/string/ffs.c @@ -18,13 +18,16 @@ #include <limits.h> #define ffsl __something_else #include <string.h> - #undef ffs +#include <math-use-builtins.h> /* Find the first bit set in I. */ int __ffs (int i) { +#if USE_FFS_BUILTIN + return __builtin_ffs (i); +#else static const unsigned char table[] = { 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, @@ -42,6 +45,7 @@ __ffs (int i) a = x <= 0xffff ? (x <= 0xff ? 0 : 8) : (x <= 0xffffff ? 16 : 24); return table[x >> a] + a; +#endif } weak_alias (__ffs, ffs) libc_hidden_def (__ffs) diff --git a/string/ffsll.c b/string/ffsll.c index 7d16250026..0ec39a0c56 100644 --- a/string/ffsll.c +++ b/string/ffsll.c @@ -18,20 +18,26 @@ #include <limits.h> #define ffsl __something_else #include <string.h> - #undef ffsll +#include <math-use-builtins.h> +#include <libc-diag.h> /* Find the first bit set in I. */ int -ffsll (long long int i) +__ffsll (long long int i) { +#if USE_FFSLL_BUILTIN + return __builtin_ffsll (i); +#else unsigned long long int x = i & -i; if (x <= 0xffffffff) return ffs (i); else return 32 + ffs (i >> 32); +#endif } +weak_alias (__ffsll, ffsll) #if ULONG_MAX != UINT_MAX #undef ffsl |