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[libc++] Simplify the implementation of __next_prime a bit #143512

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Merged
merged 1 commit into from
Jun 11, 2025
Merged

[libc++] Simplify the implementation of __next_prime a bit #143512

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20 changes: 9 additions & 11 deletions libcxx/src/hash.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,6 @@
#include <__hash_table>
#include <algorithm>
#include <stdexcept>
#include <type_traits>

_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wtautological-constant-out-of-range-compare")

Expand Down Expand Up @@ -52,16 +51,15 @@ const unsigned indices[] = {
// are fewer potential primes to search, and fewer potential primes to divide
// against.

template <size_t _Sz = sizeof(size_t)>
inline _LIBCPP_HIDE_FROM_ABI typename enable_if<_Sz == 4, void>::type __check_for_overflow(size_t N) {
if (N > 0xFFFFFFFB)
std::__throw_overflow_error("__next_prime overflow");
}

template <size_t _Sz = sizeof(size_t)>
inline _LIBCPP_HIDE_FROM_ABI typename enable_if<_Sz == 8, void>::type __check_for_overflow(size_t N) {
if (N > 0xFFFFFFFFFFFFFFC5ull)
std::__throw_overflow_error("__next_prime overflow");
inline void __check_for_overflow(size_t N) {
if constexpr (sizeof(size_t) == 4) {
if (N > 0xFFFFFFFB)
std::__throw_overflow_error("__next_prime overflow");
} else {
static_assert(sizeof(size_t) == 8);
if (N > 0xFFFFFFFFFFFFFFC5ull)
std::__throw_overflow_error("__next_prime overflow");
}
}

size_t __next_prime(size_t n) {
Expand Down
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