https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109442
--- Comment #27 from Jonathan Wakely <redi at gcc dot gnu.org> ---
vector::size() is called **very often** so needs to be as fast as possible.
Does this still inline identically?
I tried something like that in r14-1452-gfb409a15d9babc and reverted it in
r14-1470-gb7b255e77a2719, but my _M_invariant() function was more complicated.
Maybe the other part of my _M_invariant() function could be added directly to
capacity()
--- a/libstdc++-v3/include/bits/stl_vector.h
+++ b/libstdc++-v3/include/bits/stl_vector.h
@@ -1201,8 +1201,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
size_type
capacity() const _GLIBCXX_NOEXCEPT
{
- return size_type(this->_M_impl._M_end_of_storage
- - this->_M_impl._M_start);
+ ptrdiff_t __dif
+ = this->_M_impl._M_end_of_storage - this->_M_impl._M_start;
+ if (__dir < 0)
+ __builtin_unreachable();
+ return size_type(__dif);
}
/**
