diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index aeb5c2f..6566823 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -8547,11 +8547,28 @@ nonzero_bits (x, mode) break; case FFS: - case CLZ: - case CTZ: case POPCOUNT: /* This is at most the number of bits in the mode. */ - nonzero = ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width) + 1)) - 1; + nonzero = ((HOST_WIDE_INT) 2 << (floor_log2 (mode_width))) - 1; + break; + + case CLZ: + /* If CLZ has a known value at zero, then the nonzero bits are + that value, plus the number of bits in the mode minus one. */ + if (CLZ_DEFINED_VALUE_AT_ZERO (mode, nonzero)) + nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1; + else + nonzero = -1; + break; + + case CTZ: + /* If CTZ has a known value at zero, then the nonzero bits are + that value, plus the number of bits in the mode minus one. */ + if (CTZ_DEFINED_VALUE_AT_ZERO (mode, nonzero)) + nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1; + else + nonzero = -1; + break; break; case PARITY: |