2015-09-29 Steven G. Kargl <kargl@gcc.gnu.org>
[official-gcc.git] / gcc / sbitmap.c
blob070f93638142434d39d29e7e4549930edc46ee5b
1 /* Simple bitmaps.
2 Copyright (C) 1999-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "sbitmap.h"
25 /* This suffices for roughly 99% of the hosts we run on, and the rest
26 don't have 256 bit integers. */
27 #if SBITMAP_ELT_BITS > 255
28 #error Need to increase size of datatype used for popcount
29 #endif
31 #if GCC_VERSION >= 3400
32 # if SBITMAP_ELT_BITS == HOST_BITS_PER_LONG
33 # define do_popcount(x) __builtin_popcountl (x)
34 # elif SBITMAP_ELT_BITS == HOST_BITS_PER_LONGLONG
35 # define do_popcount(x) __builtin_popcountll (x)
36 # else
37 # error "internal error: sbitmap.h and hwint.h are inconsistent"
38 # endif
39 #else
40 static unsigned long sbitmap_elt_popcount (SBITMAP_ELT_TYPE);
41 # define do_popcount(x) sbitmap_elt_popcount (x)
42 #endif
44 typedef SBITMAP_ELT_TYPE *sbitmap_ptr;
45 typedef const SBITMAP_ELT_TYPE *const_sbitmap_ptr;
47 /* Return the size in bytes of a bitmap MAP. */
49 static inline unsigned int sbitmap_size_bytes (const_sbitmap map)
51 return map->size * sizeof (SBITMAP_ELT_TYPE);
54 /* This macro controls debugging that is as expensive as the
55 operations it verifies. */
57 /* #define BITMAP_DEBUGGING */
58 #ifdef BITMAP_DEBUGGING
60 /* Verify the population count of sbitmap A matches the cached value,
61 if there is a cached value. */
63 static void
64 sbitmap_verify_popcount (const_sbitmap a)
66 unsigned ix;
67 unsigned int lastword;
69 if (!a->popcount)
70 return;
72 lastword = a->size;
73 for (ix = 0; ix < lastword; ix++)
74 gcc_assert (a->popcount[ix] == do_popcount (a->elms[ix]));
76 #endif
78 /* Bitmap manipulation routines. */
80 /* Allocate a simple bitmap of N_ELMS bits. */
82 sbitmap
83 sbitmap_alloc (unsigned int n_elms)
85 unsigned int bytes, size, amt;
86 sbitmap bmap;
88 size = SBITMAP_SET_SIZE (n_elms);
89 bytes = size * sizeof (SBITMAP_ELT_TYPE);
90 amt = (sizeof (struct simple_bitmap_def)
91 + bytes - sizeof (SBITMAP_ELT_TYPE));
92 bmap = (sbitmap) xmalloc (amt);
93 bmap->n_bits = n_elms;
94 bmap->size = size;
95 bmap->popcount = NULL;
96 return bmap;
99 /* Allocate a simple bitmap of N_ELMS bits, and a popcount array. */
101 sbitmap
102 sbitmap_alloc_with_popcount (unsigned int n_elms)
104 sbitmap const bmap = sbitmap_alloc (n_elms);
105 bmap->popcount = XNEWVEC (unsigned char, bmap->size);
106 return bmap;
109 /* Resize a simple bitmap BMAP to N_ELMS bits. If increasing the
110 size of BMAP, clear the new bits to zero if the DEF argument
111 is zero, and set them to one otherwise. */
113 sbitmap
114 sbitmap_resize (sbitmap bmap, unsigned int n_elms, int def)
116 unsigned int bytes, size, amt;
117 unsigned int last_bit;
119 size = SBITMAP_SET_SIZE (n_elms);
120 bytes = size * sizeof (SBITMAP_ELT_TYPE);
121 if (bytes > sbitmap_size_bytes (bmap))
123 amt = (sizeof (struct simple_bitmap_def)
124 + bytes - sizeof (SBITMAP_ELT_TYPE));
125 bmap = (sbitmap) xrealloc (bmap, amt);
126 if (bmap->popcount)
127 bmap->popcount = XRESIZEVEC (unsigned char, bmap->popcount, size);
130 if (n_elms > bmap->n_bits)
132 if (def)
134 memset (bmap->elms + bmap->size, -1,
135 bytes - sbitmap_size_bytes (bmap));
137 /* Set the new bits if the original last element. */
138 last_bit = bmap->n_bits % SBITMAP_ELT_BITS;
139 if (last_bit)
140 bmap->elms[bmap->size - 1]
141 |= ~((SBITMAP_ELT_TYPE)-1 >> (SBITMAP_ELT_BITS - last_bit));
143 /* Clear the unused bit in the new last element. */
144 last_bit = n_elms % SBITMAP_ELT_BITS;
145 if (last_bit)
146 bmap->elms[size - 1]
147 &= (SBITMAP_ELT_TYPE)-1 >> (SBITMAP_ELT_BITS - last_bit);
149 else
151 memset (bmap->elms + bmap->size, 0,
152 bytes - sbitmap_size_bytes (bmap));
153 if (bmap->popcount)
154 memset (bmap->popcount + bmap->size, 0,
155 (size * sizeof (unsigned char))
156 - (bmap->size * sizeof (unsigned char)));
160 else if (n_elms < bmap->n_bits)
162 /* Clear the surplus bits in the last word. */
163 last_bit = n_elms % SBITMAP_ELT_BITS;
164 if (last_bit)
166 bmap->elms[size - 1]
167 &= (SBITMAP_ELT_TYPE)-1 >> (SBITMAP_ELT_BITS - last_bit);
168 if (bmap->popcount)
169 bmap->popcount[size - 1] = do_popcount (bmap->elms[size - 1]);
173 bmap->n_bits = n_elms;
174 bmap->size = size;
175 return bmap;
178 /* Re-allocate a simple bitmap of N_ELMS bits. New storage is uninitialized. */
180 sbitmap
181 sbitmap_realloc (sbitmap src, unsigned int n_elms)
183 unsigned int bytes, size, amt;
184 sbitmap bmap;
186 size = SBITMAP_SET_SIZE (n_elms);
187 bytes = size * sizeof (SBITMAP_ELT_TYPE);
188 amt = (sizeof (struct simple_bitmap_def)
189 + bytes - sizeof (SBITMAP_ELT_TYPE));
191 if (sbitmap_size_bytes (src) >= bytes)
193 src->n_bits = n_elms;
194 return src;
197 bmap = (sbitmap) xrealloc (src, amt);
198 bmap->n_bits = n_elms;
199 bmap->size = size;
200 return bmap;
203 /* Allocate a vector of N_VECS bitmaps of N_ELMS bits. */
205 sbitmap *
206 sbitmap_vector_alloc (unsigned int n_vecs, unsigned int n_elms)
208 unsigned int i, bytes, offset, elm_bytes, size, amt, vector_bytes;
209 sbitmap *bitmap_vector;
211 size = SBITMAP_SET_SIZE (n_elms);
212 bytes = size * sizeof (SBITMAP_ELT_TYPE);
213 elm_bytes = (sizeof (struct simple_bitmap_def)
214 + bytes - sizeof (SBITMAP_ELT_TYPE));
215 vector_bytes = n_vecs * sizeof (sbitmap *);
217 /* Round up `vector_bytes' to account for the alignment requirements
218 of an sbitmap. One could allocate the vector-table and set of sbitmaps
219 separately, but that requires maintaining two pointers or creating
220 a cover struct to hold both pointers (so our result is still just
221 one pointer). Neither is a bad idea, but this is simpler for now. */
223 /* Based on DEFAULT_ALIGNMENT computation in obstack.c. */
224 struct { char x; SBITMAP_ELT_TYPE y; } align;
225 int alignment = (char *) & align.y - & align.x;
226 vector_bytes = (vector_bytes + alignment - 1) & ~ (alignment - 1);
229 amt = vector_bytes + (n_vecs * elm_bytes);
230 bitmap_vector = (sbitmap *) xmalloc (amt);
232 for (i = 0, offset = vector_bytes; i < n_vecs; i++, offset += elm_bytes)
234 sbitmap b = (sbitmap) ((char *) bitmap_vector + offset);
236 bitmap_vector[i] = b;
237 b->n_bits = n_elms;
238 b->size = size;
239 b->popcount = NULL;
242 return bitmap_vector;
245 /* Copy sbitmap SRC to DST. */
247 void
248 bitmap_copy (sbitmap dst, const_sbitmap src)
250 memcpy (dst->elms, src->elms, sizeof (SBITMAP_ELT_TYPE) * dst->size);
251 if (dst->popcount)
252 memcpy (dst->popcount, src->popcount, sizeof (unsigned char) * dst->size);
255 /* Determine if a == b. */
257 bitmap_equal_p (const_sbitmap a, const_sbitmap b)
259 return !memcmp (a->elms, b->elms, sizeof (SBITMAP_ELT_TYPE) * a->size);
262 /* Return true if the bitmap is empty. */
264 bool
265 bitmap_empty_p (const_sbitmap bmap)
267 unsigned int i;
268 for (i=0; i<bmap->size; i++)
269 if (bmap->elms[i])
270 return false;
272 return true;
276 /* Zero all elements in a bitmap. */
278 void
279 bitmap_clear (sbitmap bmap)
281 memset (bmap->elms, 0, sbitmap_size_bytes (bmap));
282 if (bmap->popcount)
283 memset (bmap->popcount, 0, bmap->size * sizeof (unsigned char));
286 /* Set all elements in a bitmap to ones. */
288 void
289 bitmap_ones (sbitmap bmap)
291 unsigned int last_bit;
293 memset (bmap->elms, -1, sbitmap_size_bytes (bmap));
294 if (bmap->popcount)
295 memset (bmap->popcount, -1, bmap->size * sizeof (unsigned char));
297 last_bit = bmap->n_bits % SBITMAP_ELT_BITS;
298 if (last_bit)
300 bmap->elms[bmap->size - 1]
301 = (SBITMAP_ELT_TYPE)-1 >> (SBITMAP_ELT_BITS - last_bit);
302 if (bmap->popcount)
303 bmap->popcount[bmap->size - 1]
304 = do_popcount (bmap->elms[bmap->size - 1]);
308 /* Zero a vector of N_VECS bitmaps. */
310 void
311 bitmap_vector_clear (sbitmap *bmap, unsigned int n_vecs)
313 unsigned int i;
315 for (i = 0; i < n_vecs; i++)
316 bitmap_clear (bmap[i]);
319 /* Set a vector of N_VECS bitmaps to ones. */
321 void
322 bitmap_vector_ones (sbitmap *bmap, unsigned int n_vecs)
324 unsigned int i;
326 for (i = 0; i < n_vecs; i++)
327 bitmap_ones (bmap[i]);
330 /* Set DST to be A union (B - C).
331 DST = A | (B & ~C).
332 Returns true if any change is made. */
334 bool
335 bitmap_ior_and_compl (sbitmap dst, const_sbitmap a, const_sbitmap b, const_sbitmap c)
337 unsigned int i, n = dst->size;
338 sbitmap_ptr dstp = dst->elms;
339 const_sbitmap_ptr ap = a->elms;
340 const_sbitmap_ptr bp = b->elms;
341 const_sbitmap_ptr cp = c->elms;
342 SBITMAP_ELT_TYPE changed = 0;
344 gcc_assert (!dst->popcount);
346 for (i = 0; i < n; i++)
348 const SBITMAP_ELT_TYPE tmp = *ap++ | (*bp++ & ~*cp++);
349 changed |= *dstp ^ tmp;
350 *dstp++ = tmp;
353 return changed != 0;
356 /* Set bitmap DST to the bitwise negation of the bitmap SRC. */
358 void
359 bitmap_not (sbitmap dst, const_sbitmap src)
361 unsigned int i, n = dst->size;
362 sbitmap_ptr dstp = dst->elms;
363 const_sbitmap_ptr srcp = src->elms;
364 unsigned int last_bit;
366 gcc_assert (!dst->popcount);
368 for (i = 0; i < n; i++)
369 *dstp++ = ~*srcp++;
371 /* Zero all bits past n_bits, by ANDing dst with bitmap_ones. */
372 last_bit = src->n_bits % SBITMAP_ELT_BITS;
373 if (last_bit)
374 dst->elms[n-1] = dst->elms[n-1]
375 & ((SBITMAP_ELT_TYPE)-1 >> (SBITMAP_ELT_BITS - last_bit));
378 /* Set the bits in DST to be the difference between the bits
379 in A and the bits in B. i.e. dst = a & (~b). */
381 void
382 bitmap_and_compl (sbitmap dst, const_sbitmap a, const_sbitmap b)
384 unsigned int i, dst_size = dst->size;
385 unsigned int min_size = dst->size;
386 sbitmap_ptr dstp = dst->elms;
387 const_sbitmap_ptr ap = a->elms;
388 const_sbitmap_ptr bp = b->elms;
390 gcc_assert (!dst->popcount);
392 /* A should be at least as large as DEST, to have a defined source. */
393 gcc_assert (a->size >= dst_size);
394 /* If minuend is smaller, we simply pretend it to be zero bits, i.e.
395 only copy the subtrahend into dest. */
396 if (b->size < min_size)
397 min_size = b->size;
398 for (i = 0; i < min_size; i++)
399 *dstp++ = *ap++ & (~*bp++);
400 /* Now fill the rest of dest from A, if B was too short.
401 This makes sense only when destination and A differ. */
402 if (dst != a && i != dst_size)
403 for (; i < dst_size; i++)
404 *dstp++ = *ap++;
407 /* Return true if there are any bits set in A are also set in B.
408 Return false otherwise. */
410 bool
411 bitmap_intersect_p (const_sbitmap a, const_sbitmap b)
413 const_sbitmap_ptr ap = a->elms;
414 const_sbitmap_ptr bp = b->elms;
415 unsigned int i, n;
417 n = MIN (a->size, b->size);
418 for (i = 0; i < n; i++)
419 if ((*ap++ & *bp++) != 0)
420 return true;
422 return false;
425 /* Set DST to be (A and B).
426 Return nonzero if any change is made. */
428 bool
429 bitmap_and (sbitmap dst, const_sbitmap a, const_sbitmap b)
431 unsigned int i, n = dst->size;
432 sbitmap_ptr dstp = dst->elms;
433 const_sbitmap_ptr ap = a->elms;
434 const_sbitmap_ptr bp = b->elms;
435 bool has_popcount = dst->popcount != NULL;
436 unsigned char *popcountp = dst->popcount;
437 SBITMAP_ELT_TYPE changed = 0;
439 for (i = 0; i < n; i++)
441 const SBITMAP_ELT_TYPE tmp = *ap++ & *bp++;
442 SBITMAP_ELT_TYPE wordchanged = *dstp ^ tmp;
443 if (has_popcount)
445 if (wordchanged)
446 *popcountp = do_popcount (tmp);
447 popcountp++;
449 *dstp++ = tmp;
450 changed |= wordchanged;
452 #ifdef BITMAP_DEBUGGING
453 if (has_popcount)
454 sbitmap_verify_popcount (dst);
455 #endif
456 return changed != 0;
459 /* Set DST to be (A xor B)).
460 Return nonzero if any change is made. */
462 bool
463 bitmap_xor (sbitmap dst, const_sbitmap a, const_sbitmap b)
465 unsigned int i, n = dst->size;
466 sbitmap_ptr dstp = dst->elms;
467 const_sbitmap_ptr ap = a->elms;
468 const_sbitmap_ptr bp = b->elms;
469 bool has_popcount = dst->popcount != NULL;
470 unsigned char *popcountp = dst->popcount;
471 SBITMAP_ELT_TYPE changed = 0;
473 for (i = 0; i < n; i++)
475 const SBITMAP_ELT_TYPE tmp = *ap++ ^ *bp++;
476 SBITMAP_ELT_TYPE wordchanged = *dstp ^ tmp;
477 if (has_popcount)
479 if (wordchanged)
480 *popcountp = do_popcount (tmp);
481 popcountp++;
483 *dstp++ = tmp;
484 changed |= wordchanged;
486 #ifdef BITMAP_DEBUGGING
487 if (has_popcount)
488 sbitmap_verify_popcount (dst);
489 #endif
490 return changed != 0;
493 /* Set DST to be (A or B)).
494 Return nonzero if any change is made. */
496 bool
497 bitmap_ior (sbitmap dst, const_sbitmap a, const_sbitmap b)
499 unsigned int i, n = dst->size;
500 sbitmap_ptr dstp = dst->elms;
501 const_sbitmap_ptr ap = a->elms;
502 const_sbitmap_ptr bp = b->elms;
503 bool has_popcount = dst->popcount != NULL;
504 unsigned char *popcountp = dst->popcount;
505 SBITMAP_ELT_TYPE changed = 0;
507 for (i = 0; i < n; i++)
509 const SBITMAP_ELT_TYPE tmp = *ap++ | *bp++;
510 SBITMAP_ELT_TYPE wordchanged = *dstp ^ tmp;
511 if (has_popcount)
513 if (wordchanged)
514 *popcountp = do_popcount (tmp);
515 popcountp++;
517 *dstp++ = tmp;
518 changed |= wordchanged;
520 #ifdef BITMAP_DEBUGGING
521 if (has_popcount)
522 sbitmap_verify_popcount (dst);
523 #endif
524 return changed != 0;
527 /* Return nonzero if A is a subset of B. */
529 bool
530 bitmap_subset_p (const_sbitmap a, const_sbitmap b)
532 unsigned int i, n = a->size;
533 const_sbitmap_ptr ap, bp;
535 for (ap = a->elms, bp = b->elms, i = 0; i < n; i++, ap++, bp++)
536 if ((*ap | *bp) != *bp)
537 return false;
539 return true;
542 /* Set DST to be (A or (B and C)).
543 Return nonzero if any change is made. */
545 bool
546 bitmap_or_and (sbitmap dst, const_sbitmap a, const_sbitmap b, const_sbitmap c)
548 unsigned int i, n = dst->size;
549 sbitmap_ptr dstp = dst->elms;
550 const_sbitmap_ptr ap = a->elms;
551 const_sbitmap_ptr bp = b->elms;
552 const_sbitmap_ptr cp = c->elms;
553 SBITMAP_ELT_TYPE changed = 0;
555 gcc_assert (!dst->popcount);
557 for (i = 0; i < n; i++)
559 const SBITMAP_ELT_TYPE tmp = *ap++ | (*bp++ & *cp++);
560 changed |= *dstp ^ tmp;
561 *dstp++ = tmp;
564 return changed != 0;
567 /* Set DST to be (A and (B or C)).
568 Return nonzero if any change is made. */
570 bool
571 bitmap_and_or (sbitmap dst, const_sbitmap a, const_sbitmap b, const_sbitmap c)
573 unsigned int i, n = dst->size;
574 sbitmap_ptr dstp = dst->elms;
575 const_sbitmap_ptr ap = a->elms;
576 const_sbitmap_ptr bp = b->elms;
577 const_sbitmap_ptr cp = c->elms;
578 SBITMAP_ELT_TYPE changed = 0;
580 gcc_assert (!dst->popcount);
582 for (i = 0; i < n; i++)
584 const SBITMAP_ELT_TYPE tmp = *ap++ & (*bp++ | *cp++);
585 changed |= *dstp ^ tmp;
586 *dstp++ = tmp;
589 return changed != 0;
592 /* Return number of first bit set in the bitmap, -1 if none. */
595 bitmap_first_set_bit (const_sbitmap bmap)
597 unsigned int n = 0;
598 sbitmap_iterator sbi;
600 EXECUTE_IF_SET_IN_BITMAP (bmap, 0, n, sbi)
601 return n;
602 return -1;
605 /* Return number of last bit set in the bitmap, -1 if none. */
608 bitmap_last_set_bit (const_sbitmap bmap)
610 int i;
611 const SBITMAP_ELT_TYPE *const ptr = bmap->elms;
613 for (i = bmap->size - 1; i >= 0; i--)
615 const SBITMAP_ELT_TYPE word = ptr[i];
617 if (word != 0)
619 unsigned int index = (i + 1) * SBITMAP_ELT_BITS - 1;
620 SBITMAP_ELT_TYPE mask
621 = (SBITMAP_ELT_TYPE) 1 << (SBITMAP_ELT_BITS - 1);
623 while (1)
625 if ((word & mask) != 0)
626 return index;
628 mask >>= 1;
629 index--;
634 return -1;
637 void
638 dump_bitmap (FILE *file, const_sbitmap bmap)
640 unsigned int i, n, j;
641 unsigned int set_size = bmap->size;
642 unsigned int total_bits = bmap->n_bits;
644 fprintf (file, " ");
645 for (i = n = 0; i < set_size && n < total_bits; i++)
646 for (j = 0; j < SBITMAP_ELT_BITS && n < total_bits; j++, n++)
648 if (n != 0 && n % 10 == 0)
649 fprintf (file, " ");
651 fprintf (file, "%d",
652 (bmap->elms[i] & ((SBITMAP_ELT_TYPE) 1 << j)) != 0);
655 fprintf (file, "\n");
658 DEBUG_FUNCTION void
659 debug_raw (simple_bitmap_def &ref)
661 dump_bitmap (stderr, &ref);
664 DEBUG_FUNCTION void
665 debug_raw (simple_bitmap_def *ptr)
667 if (ptr)
668 debug_raw (*ptr);
669 else
670 fprintf (stderr, "<nil>\n");
673 void
674 dump_bitmap_file (FILE *file, const_sbitmap bmap)
676 unsigned int i, pos;
678 fprintf (file, "n_bits = %d, set = {", bmap->n_bits);
680 for (pos = 30, i = 0; i < bmap->n_bits; i++)
681 if (bitmap_bit_p (bmap, i))
683 if (pos > 70)
685 fprintf (file, "\n ");
686 pos = 0;
689 fprintf (file, "%d ", i);
690 pos += 2 + (i >= 10) + (i >= 100) + (i >= 1000);
693 fprintf (file, "}\n");
696 DEBUG_FUNCTION void
697 debug_bitmap (const_sbitmap bmap)
699 dump_bitmap_file (stderr, bmap);
702 DEBUG_FUNCTION void
703 debug (simple_bitmap_def &ref)
705 dump_bitmap_file (stderr, &ref);
708 DEBUG_FUNCTION void
709 debug (simple_bitmap_def *ptr)
711 if (ptr)
712 debug (*ptr);
713 else
714 fprintf (stderr, "<nil>\n");
717 void
718 dump_bitmap_vector (FILE *file, const char *title, const char *subtitle,
719 sbitmap *bmaps, int n_maps)
721 int i;
723 fprintf (file, "%s\n", title);
724 for (i = 0; i < n_maps; i++)
726 fprintf (file, "%s %d\n", subtitle, i);
727 dump_bitmap (file, bmaps[i]);
730 fprintf (file, "\n");
733 #if GCC_VERSION < 3400
734 /* Table of number of set bits in a character, indexed by value of char. */
735 static const unsigned char popcount_table[] =
737 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
738 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
739 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
740 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
741 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
742 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
743 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
744 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8,
747 /* Count the bits in an SBITMAP element A. */
749 static unsigned long
750 sbitmap_elt_popcount (SBITMAP_ELT_TYPE a)
752 unsigned long ret = 0;
753 unsigned i;
755 if (a == 0)
756 return 0;
758 /* Just do this the table way for now */
759 for (i = 0; i < SBITMAP_ELT_BITS; i += 8)
760 ret += popcount_table[(a >> i) & 0xff];
761 return ret;
763 #endif