[libcxx-commits] [libcxx] [libc++] Optimize num_get integral functions (PR #121795)

[Florian Hahn via libcxx-commits]

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@@ -83,11 +85,22 @@ struct __num_get : protected __num_get_base {
       unsigned*& __g_end,
       _CharT* __atoms);
 
-  _LIBCPP_HIDE_FROM_ABI static string __stage2_int_prep(ios_base& __iob, _CharT& __thousands_sep) {
-    locale __loc                 = __iob.getloc();
-    const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__loc);
-    __thousands_sep              = __np.thousands_sep();
-    return __np.grouping();
+  _LIBCPP_HIDE_FROM_ABI static ptrdiff_t __atoms_offset(const _CharT* __atoms, _CharT __val) {
+#  if _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS
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fhahn wrote:

The last change to support `__builtin_assume_derefenceable` with pointer differences landed in `main` recently, so somehing like https://clang.godbolt.org/z/sEPbx3YaM now works.

Please let me know if anything else is missing

https://github.com/llvm/llvm-project/pull/121795