diff options
Diffstat (limited to 'lib/count-trailing-zeros.h')
| -rw-r--r-- | lib/count-trailing-zeros.h | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/lib/count-trailing-zeros.h b/lib/count-trailing-zeros.h index 9a989a43245..61fbdf29801 100644 --- a/lib/count-trailing-zeros.h +++ b/lib/count-trailing-zeros.h @@ -43,8 +43,10 @@ extern "C" { # define COUNT_TRAILING_ZEROS(BUILTIN, MSC_BUILTIN, TYPE) \ return x ? BUILTIN (x) : CHAR_BIT * sizeof x; #elif _MSC_VER -# pragma intrinsic _BitScanForward -# pragma intrinsic _BitScanForward64 +# pragma intrinsic (_BitScanForward) +# if defined _M_X64 +# pragma intrinsic (_BitScanForward64) +# endif # define COUNT_TRAILING_ZEROS(BUILTIN, MSC_BUILTIN, TYPE) \ do \ { \ @@ -101,8 +103,18 @@ count_trailing_zeros_l (unsigned long int x) COUNT_TRAILING_ZEROS_INLINE int count_trailing_zeros_ll (unsigned long long int x) { +#if (defined _MSC_VER && !defined __clang__) && !defined _M_X64 + /* 32-bit MSVC does not have _BitScanForward64, only _BitScanForward. */ + unsigned long result; + if (_BitScanForward (&result, (unsigned long) x)) + return result; + if (_BitScanForward (&result, (unsigned long) (x >> 32))) + return result + 32; + return CHAR_BIT * sizeof x; +#else COUNT_TRAILING_ZEROS (__builtin_ctzll, _BitScanForward64, unsigned long long int); +#endif } #ifdef __cplusplus |