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Use __builtin_popcount in __sched_cpucount [BZ #21696] 

posix/sched_cpucount.c assumes that size of __cpu_mask == size of long,
which is incorrect for x32.  This patch uses __builtin_popcount, which
is availabe in GCC 4.9, in posix/sched_cpucount.c.

Tested on i686, x86-64 and x32 with multi-arch disabled.

	[BZ #21696]
	* posix/sched_cpucount.c: Don't include <limits.h>.
	(__sched_cpucount): Use __builtin_popcount.
This commit is contained in:
H.J. Lu 2017-07-01 07:29:19 -07:00
parent 47ea614b9a
commit 8dc6133eff
2 changed files with 17 additions and 17 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2017-07-01 Florian Weimer <fweimer@redhat.com>
H.J. Lu <hongjiu.lu@intel.com>
[BZ #21696]
* posix/sched_cpucount.c: Don't include <limits.h>.
(__sched_cpucount): Use __builtin_popcount.
2017-07-01 Ramana Radhakrishnan <ramana.gcc@googlemail.com>
* sysdeps/unix/sysv/aarch64/cpu-features.c (init_cpu_features):

27
posix/sched_cpucount.c
View File

@ -15,7 +15,6 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <limits.h>
#include <sched.h>
@ -36,22 +35,16 @@ __sched_cpucount (size_t setsize, const cpu_set_t *setp)
if (l == 0)
continue;
# if LONG_BIT > 32
l = (l & 0x5555555555555555ul) + ((l >> 1) & 0x5555555555555555ul);
l = (l & 0x3333333333333333ul) + ((l >> 2) & 0x3333333333333333ul);
l = (l & 0x0f0f0f0f0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0f0f0f0f0ful);
l = (l & 0x00ff00ff00ff00fful) + ((l >> 8) & 0x00ff00ff00ff00fful);
l = (l & 0x0000ffff0000fffful) + ((l >> 16) & 0x0000ffff0000fffful);
l = (l & 0x00000000fffffffful) + ((l >> 32) & 0x00000000fffffffful);
# else
l = (l & 0x55555555ul) + ((l >> 1) & 0x55555555ul);
l = (l & 0x33333333ul) + ((l >> 2) & 0x33333333ul);
l = (l & 0x0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0ful);
l = (l & 0x00ff00fful) + ((l >> 8) & 0x00ff00fful);
l = (l & 0x0000fffful) + ((l >> 16) & 0x0000fffful);
# endif
s += l;
_Static_assert (sizeof (l) == sizeof (unsigned int)
|| sizeof (l) == sizeof (unsigned long)
|| sizeof (l) == sizeof (unsigned long long),
"sizeof (__cpu_mask");
if (sizeof (__cpu_mask) == sizeof (unsigned int))
s += __builtin_popcount (l);
else if (sizeof (__cpu_mask) == sizeof (unsigned long))
s += __builtin_popcountl (l);
else
s += __builtin_popcountll (l);
#endif
}