diff options
Diffstat (limited to 'gcc/bitmap.c')
| -rw-r--r-- | gcc/bitmap.c | 31 |
1 files changed, 11 insertions, 20 deletions
diff --git a/gcc/bitmap.c b/gcc/bitmap.c index 1a28788bc3e..63f0e099a05 100644 --- a/gcc/bitmap.c +++ b/gcc/bitmap.c @@ -837,33 +837,24 @@ bitmap_last_set_bit (const_bitmap a) 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); + bit_no += BITMAP_WORD_BITS - __builtin_clzl (word) - 1; #else -#if BITMAP_WORD_BITS > 64 -#error "Fill out the table." -#endif + /* Hopefully this is a twos-complement host... */ + BITMAP_WORD x = word; + x |= (x >> 1); + x |= (x >> 2); + x |= (x >> 4); + x |= (x >> 8); + x |= (x >> 16); #if BITMAP_WORD_BITS > 32 - if ((word & 0xffffffff00000000)) - word >>= 32, bit_no += 32; + x |= (x >> 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; + bit_no += bitmap_popcount (x) - 1; #endif - gcc_checking_assert (word & 1); - return bit_no; + return bit_no; } |