https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108636
--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes, that's explained above:
(In reply to GCC Commits from comment #3)
> On trunk there is a second problem, which is that the new equality
> operators for comparing directory iterators with default_sentinel use
> the shared_ptr::operator bool() conversion operator. The shared_ptr
> specializations used by directory iterators are explicitly instantiated
> in the library, but the bool conversion operators are not exported. This
> causes linker errors at -O0 or with -fkeep-inline-functions. That just
> requires the conversion operators to be exported.
That was fixed by this part:
> * config/abi/pre/gnu.ver (GLIBCXX_3.4.31): Export shared_ptr
> conversion operators for directory iterator comparisons with
> std::default_sentinel_t.
But that can't be backported to the gcc-12 branch as it would change the ABI of
the libstdc++.so.6.0.30 shared library.
I think this would solve the problem with -fkeep-inline-functions:
--- a/libstdc++-v3/include/bits/shared_ptr_base.h
+++ b/libstdc++-v3/include/bits/shared_ptr_base.h
@@ -1666,6 +1666,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return _M_ptr; }
/// Return true if the stored pointer is not null.
+#if __cplusplus >= 202002L
+ [[__gnu__::__always_inline__]]
+#endif
explicit operator bool() const noexcept
{ return _M_ptr != nullptr; }
We would only need that on the gcc-12 branch, since it works elsewhere.
