Re: [PATCH] declare std::array members attribute const [PR101831]

[Jonathan Wakely <jwakely@redhat.com>]

On Tue, 1 Feb 2022 at 18:54, Martin Sebor via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> Passing an uninitialized object to a function that takes its argument
> by const reference is diagnosed by -Wmaybe-uninitialized because most
> such functions read the argument.  The exceptions are functions that
> don't access the object but instead use its address to compute
> a result.  This includes a number of std::array member functions such
> as std::array<N>::size() which returns the template argument N.  Such
> functions may be candidates for attribute const which also avoids
> the warning.  The attribute typically only benefits extern functions
> that IPA cannot infer the property from, but in this case it helps
> avoid the warning which runs very early on, even without optimization
> or inlining.  The attached patch adds the attribute to a subset of
> those member functions of std::array.  (It doesn't add it to const
> member functions like cbegin() or front() that return a const_iterator
> or const reference to the internal data.)
>
> It might be possible to infer this property from inline functions
> earlier on than during IPA and avoid having to annotate them explicitly.
> That seems like an enhancement worth considering in the future.
>
> Tested on x86_64-linux.
>
> Martin

new file mode 100644
index 00000000000..b7743adf3c9
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/array/iterators/begin_end.cc
@@ -0,0 +1,56 @@
+// { dg-do compile { target c++11 } }
+//
+// Copyright (C) 2011-2022 Free Software Foundation, Inc.

Those dates look wrong. I no longer bother putting a license text and
copyright notice on simple tests like this. It's meaningless to assert
copyright on something so trivial that doesn't do anything.