From: Ryan Libby <rli...@freebsd.org> We have a couple optimizations for when the bitset is known to be just one word. But with dynamically sized bitsets, it was actually more work to determine the size than just to do the necessary computation. Now, only use the optimization when the size is known to be constant.
Reviewed by: markj Discussed with: jeff Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D22639 --- newlib/libc/sys/rtems/include/sys/bitset.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/newlib/libc/sys/rtems/include/sys/bitset.h b/newlib/libc/sys/rtems/include/sys/bitset.h index d119c23ca..0334939c9 100644 --- a/newlib/libc/sys/rtems/include/sys/bitset.h +++ b/newlib/libc/sys/rtems/include/sys/bitset.h @@ -37,12 +37,19 @@ #include <sys/_types.h> #include <machine/_bitcount.h> +/* + * Whether expr is both constant and true. Result is itself constant. + * Used to enable optimizations for sets with a known small size. + */ +#define __constexpr_cond(expr) (__builtin_constant_p((expr)) && (expr)) + #define __bitset_mask(_s, n) \ - (1L << ((__bitset_words((_s)) == 1) ? \ + (1L << (__constexpr_cond(__bitset_words((_s)) == 1) ? \ (__size_t)(n) : ((n) % _BITSET_BITS))) #define __bitset_word(_s, n) \ - ((__bitset_words((_s)) == 1) ? 0 : ((n) / _BITSET_BITS)) + (__constexpr_cond(__bitset_words((_s)) == 1) ? \ + 0 : ((n) / _BITSET_BITS)) #define BIT_CLR(_s, n, p) \ ((p)->__bits[__bitset_word(_s, n)] &= ~__bitset_mask((_s), (n))) -- 2.35.3 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
