[libcxx-commits] [libcxx] [libc++] Simplify bitset::{any, all} (PR #128445)

[Peng Liu via libcxx-commits]

https://github.com/winner245 created https://github.com/llvm/llvm-project/pull/128445

The `any()` and `all()` member functions of `bitset` are implemented using the same bitwise logic as `std::find()` with `__bit_iterator` optimizations. Thus, we simplify `any()` and `all()` to call `std::find` directly, which is now inlined within the class.  

>From 30e237cf2f24727d56e204dcad9fac6192a9d876 Mon Sep 17 00:00:00 2001
From: Peng Liu <winner245 at hotmail.com>
Date: Sun, 23 Feb 2025 19:11:53 -0500
Subject: [PATCH] Simplify bitset::{any, all}

---
 libcxx/include/bitset | 42 ++++++------------------------------------
 1 file changed, 6 insertions(+), 36 deletions(-)

diff --git a/libcxx/include/bitset b/libcxx/include/bitset
index ab1dda739c7d5..c34fa550a3f19 100644
--- a/libcxx/include/bitset
+++ b/libcxx/include/bitset
@@ -223,8 +223,12 @@ protected:
     return to_ullong(integral_constant < bool, _Size< sizeof(unsigned long long) * CHAR_BIT>());
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 bool all() const _NOEXCEPT;
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 bool any() const _NOEXCEPT;
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 bool all() const _NOEXCEPT {
+    return std::find(__make_iter(0), __make_iter(_Size), false) == __make_iter(_Size);
+  }
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 bool any() const _NOEXCEPT {
+    return std::find(__make_iter(0), __make_iter(_Size), true) != __make_iter(_Size);
+  }
   _LIBCPP_HIDE_FROM_ABI size_t __hash_code() const _NOEXCEPT;
 
 private:
@@ -389,40 +393,6 @@ __bitset<_N_words, _Size>::to_ullong(true_type, true_type) const {
   return __r;
 }
 
-template <size_t _N_words, size_t _Size>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 bool __bitset<_N_words, _Size>::all() const _NOEXCEPT {
-  // do middle whole words
-  size_t __n                  = _Size;
-  __const_storage_pointer __p = __first_;
-  for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
-    if (~*__p)
-      return false;
-  // do last partial word
-  if (__n > 0) {
-    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
-    if (~*__p & __m)
-      return false;
-  }
-  return true;
-}
-
-template <size_t _N_words, size_t _Size>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 bool __bitset<_N_words, _Size>::any() const _NOEXCEPT {
-  // do middle whole words
-  size_t __n                  = _Size;
-  __const_storage_pointer __p = __first_;
-  for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
-    if (*__p)
-      return true;
-  // do last partial word
-  if (__n > 0) {
-    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
-    if (*__p & __m)
-      return true;
-  }
-  return false;
-}
-
 template <size_t _N_words, size_t _Size>
 inline size_t __bitset<_N_words, _Size>::__hash_code() const _NOEXCEPT {
   size_t __h = 0;