diff options
| author | Yury Norov <ynorov@nvidia.com> | 2026-04-27 18:57:05 -0400 |
|---|---|---|
| committer | Yury Norov <ynorov@nvidia.com> | 2026-05-20 11:18:27 -0400 |
| commit | 09472f591aa0b72c2dd6c693f48b2d6fea66c7ba (patch) | |
| tree | 4adce8ab4ef77de5fcb9021a406bf04059a757fd /include/linux | |
| parent | 8a51b2e874f47a6094353b59ecae421f0968fe3a (diff) | |
bitfield: wire __bf_shf to __builtin_ctzll
__bf_shf() is currently based on built-in ffsll. It's more
straightforward to wire it to __builtin_ctzll, which makes it a pure
rename.
Worth to notice that __builtin_ffsll() is buggy on GCC before 14.1:
int main() {
sizeof(struct {
int t : !(__builtin_ffsll(~0ULL) + 1 < 0);
});
}
test.c: In function 'main':
test.c:3:21: error: bit-field 't' width not an integer constant
3 | int t : !(__builtin_ffsll(~0ULL) + 1 < 0);
| ^
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124699
Reported-by: Matt Coster <matt.coster@imgtec.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202603222211.A2XiR1YU-lkp@intel.com/
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/bitfield.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index 989c214ec8a5..14f86e455a67 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -44,7 +44,7 @@ * FIELD_MODIFY(REG_FIELD_C, ®, c); */ -#define __bf_shf(x) (__builtin_ffsll(x) - 1) +#define __bf_shf __builtin_ctzll #define __scalar_type_to_unsigned_cases(type) \ unsigned type: (unsigned type)0, \ |