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bitmap.c (bitmap_last_set_bit): New function.

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* bitmap.c (bitmap_last_set_bit): New function.
	* bitmap.h (bitmap_last_set_bit): Declare.

From-SVN: r145229
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Jan Hubicka 2009-03-29 15:14:06 +02:00 committed by Jan Hubicka
parent 4ea80a418f
commit 12802c2b3d
3 changed files with 59 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2009-03-29 Jan Hubicka <jh@suse.cz>
* bitmap.c (bitmap_last_set_bit): New function.
* bitmap.h (bitmap_last_set_bit): Declare.
2009-03-29 David Ayers <ayers@fsfe.org>
PR objc/27377

53
gcc/bitmap.c
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@ -806,6 +806,59 @@ bitmap_first_set_bit (const_bitmap a)
#endif
return bit_no;
}
/* Return the bit number of the first set bit in the bitmap. The
bitmap must be non-empty. */
unsigned
bitmap_last_set_bit (const_bitmap a)
{
const bitmap_element *elt = a->current ? a->current : a->first;
unsigned bit_no;
BITMAP_WORD word;
int ix;
gcc_assert (elt);
while (elt->next)
elt = elt->next;
bit_no = elt->indx * BITMAP_ELEMENT_ALL_BITS;
for (ix = BITMAP_ELEMENT_WORDS - 1; ix >= 0; ix--)
{
word = elt->bits[ix];
if (word)
goto found_bit;
}
gcc_unreachable ();
found_bit:
bit_no += ix * BITMAP_WORD_BITS;
/* Binary search for the last set bit. */
#if GCC_VERSION >= 3004
gcc_assert (sizeof(long) == sizeof (word));
bit_no += sizeof (long) * 8 - __builtin_ctzl (word);
#else
#if BITMAP_WORD_BITS > 64
#error "Fill out the table."
#endif
#if BITMAP_WORD_BITS > 32
if ((word & 0xffffffff00000000))
word >>= 32, bit_no += 32;
#endif
if (word & 0xffff0000)
word >>= 16, bit_no += 16;
if (!(word & 0xff00))
word >>= 8, bit_no += 8;
if (!(word & 0xf0))
word >>= 4, bit_no += 4;
if (!(word & 12))
word >>= 2, bit_no += 2;
if (!(word & 2))
word >>= 1, bit_no += 1;
#endif
gcc_assert (word & 1);
return bit_no;
}
/* DST = A & B. */

1
gcc/bitmap.h
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@ -183,6 +183,7 @@ extern void bitmap_obstack_free (bitmap);
#define dump_bitmap(file, bitmap) bitmap_print (file, bitmap, "", "\n")
#define bitmap_zero(a) bitmap_clear (a)
extern unsigned bitmap_first_set_bit (const_bitmap);
extern unsigned bitmap_last_set_bit (const_bitmap);
/* Compute bitmap hash (for purposes of hashing etc.) */
extern hashval_t bitmap_hash(const_bitmap);