| /* { dg-do compile } */ |
| /* { dg-options "-O2" } */ |
| |
| static const unsigned long long magic = 0x03f08c5392f756cdULL; |
| |
| static const char table[64] = { |
| 0, 1, 12, 2, 13, 22, 17, 3, |
| 14, 33, 23, 36, 18, 58, 28, 4, |
| 62, 15, 34, 26, 24, 48, 50, 37, |
| 19, 55, 59, 52, 29, 44, 39, 5, |
| 63, 11, 21, 16, 32, 35, 57, 27, |
| 61, 25, 47, 49, 54, 51, 43, 38, |
| 10, 20, 31, 56, 60, 46, 53, 42, |
| 9, 30, 45, 41, 8, 40, 7, 6, |
| }; |
| |
| static inline int ctz1 (unsigned long long b) |
| { |
| unsigned long long lsb = b & -b; |
| return table[(lsb * magic) >> 58]; |
| } |
| |
| void f (unsigned long long x, int *p) |
| { |
| if (x != 0) |
| { |
| int a = ctz1 (x); |
| *p = a | p[a]; |
| } |
| } |
| |
| /* { dg-final { scan-assembler-times "rbit\t" 1 } } */ |
| /* { dg-final { scan-assembler-times "clz\t" 1 } } */ |
| |
