diff options
Diffstat (limited to 'libstdc++-v3/include/bits/hashtable_policy.h')
| -rw-r--r-- | libstdc++-v3/include/bits/hashtable_policy.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h index d7497711071..66fbfbe5f21 100644 --- a/libstdc++-v3/include/bits/hashtable_policy.h +++ b/libstdc++-v3/include/bits/hashtable_policy.h @@ -511,8 +511,11 @@ namespace __detail // Equivalent to return __n ? std::ceil2(__n) : 0; if (__n < 2) return __n; - return 1ul << (numeric_limits<unsigned long>::digits - - __builtin_clzl(__n - 1ul)); + const unsigned __lz = sizeof(size_t) > sizeof(long) + ? __builtin_clzll(__n - 1ull) + : __builtin_clzl(__n - 1ul); + // Doing two shifts avoids undefined behaviour when __lz == 0. + return (size_t(1) << (numeric_limits<size_t>::digits - __lz - 1)) << 1; } /// Rehash policy providing power of 2 bucket numbers. Avoids modulo |