Use __builtin_popcount () in mono_bitset_count ().

diff --git a/mono/utils/monobitset.c b/mono/utils/monobitset.c
index 5ff68938f6d94ed70392744cc0e429be1c00278c..8c49c75397272a304d7fba368fb58a6a81d5549e 100644 (file)
--- a/mono/utils/monobitset.c
+++ b/mono/utils/monobitset.c
@@ -210,25 +210,14 @@ mono_bitset_count (const MonoBitSet *set) {
        count = 0;
        for (i = 0; i < set->size / BITS_PER_CHUNK; ++i) {
                d = set->data [i];
-               /* there is probably some asm code that can do this much faster */
-               if (d) {
-#if SIZEOF_VOID_P == 8
-                       /* http://www.jjj.de/bitwizardry/bitwizardrypage.html */
-                       d -=  (d>>1) & 0x5555555555555555;
-                       d  = ((d>>2) & 0x3333333333333333) + (d & 0x3333333333333333);
-                       d  = ((d>>4) + d) & 0x0f0f0f0f0f0f0f0f;
-                       d *= 0x0101010101010101;
-                       count += d >> 56;
+#ifdef __GNUC__
+               count += __builtin_popcount (d);
 #else
-                       /* http://aggregate.org/MAGIC/ */
-                       d -= ((d >> 1) & 0x55555555);
-                       d = (((d >> 2) & 0x33333333) + (d & 0x33333333));
-                       d = (((d >> 4) + d) & 0x0f0f0f0f);
-                       d += (d >> 8);
-                       d += (d >> 16);
-                       count += (d & 0x0000003f);
-#endif
+               while (d) {
+                       count ++;
+                       d &= (d - 1);
                }
+#endif
        }
        return count;
 }