[libc-commits] [libc] [libc] `first_trailing_one(0)` should be `0`. (PR #130155)

[via libc-commits]

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@@ -1383,8 +1383,9 @@ first_trailing_zero(T value) {
 template <typename T>
 [[nodiscard]] LIBC_INLINE constexpr cpp::enable_if_t<is_big_int_v<T>, int>
 first_trailing_one(T value) {
-  return value == cpp::numeric_limits<T>::max() ? 0
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lntue wrote:

it should be just `value == 0`.  When `value` is not 0, `cpp::countr_zero(value) + 1` should be correct.

https://github.com/llvm/llvm-project/pull/130155