On Wed, 8 Dec 2021 at 19:27, Jonathan Wakely wrote:
>
> On Wed, 8 Dec 2021 at 19:21, Jonathan Wakely wrote:
> >
> > On Wed, 8 Dec 2021 at 19:17, Rainer Orth wrote:
> > >
> > > Hi Jonathan,
> > >
> > > > I've pushed this change to trunk now (it was posted and reviewed in
> > > > stage 1, I just didn't get around to pushing it until now).
> > > >
> > > > The final version of the patch is attached to this mail.
> > >
> > > unfortunately, it breaks Solaris/SPARC bootstrap:
> > >
> > > In file included from /var/gcc/regression/master/11.4-gcc-gas/build/sparc-sun-solaris2.11/sparcv9/libstdc++-v3/include/bits/shared_ptr.h:53,
> > >                  from /var/gcc/regression/master/11.4-gcc-gas/build/sparc-sun-solaris2.11/sparcv9/libstdc++-v3/include/memory:77,
> > >                  from /vol/gcc/src/hg/master/local/libstdc++-v3/include/precompiled/stdc++.h:82:
> > > /var/gcc/regression/master/11.4-gcc-gas/build/sparc-sun-solaris2.11/sparcv9/libstdc++-v3/include/bits/shared_ptr_base.h: In member function 'void std::_Sp_counted_base<_Lp>::_M_release() [with __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]':
> > > /var/gcc/regression/master/11.4-gcc-gas/build/sparc-sun-solaris2.11/sparcv9/libstdc++-v3/include/bits/shared_ptr_base.h:329:26: error: right operand of shift expression '(1 << 64)' is greater than or equal to the precision 64 of the left operand [-fpermissive]
> > >   329 |             = 1LL + (1LL << (__CHAR_BIT__ * sizeof(_Atomic_word)));
> > >       |                     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > make[9]: *** [Makefile:1875: sparc-sun-solaris2.11/bits/stdc++.h.gch/O2ggnu++0x.gch] Error 1
> > >
> > > For 64-bit SPARC, _Atomic_word is long.
> >
> > Ah yes, so we need to disable this optimization. Patch coming up ...
>
> Gah, I remembered to check that:
>
>       constexpr bool __double_word
>         = sizeof(long long) == 2 * sizeof(_Atomic_word);
>       // The ref-count members follow the vptr, so are aligned to
>       // alignof(void*).
>       constexpr bool __aligned = __alignof(long long) <= alignof(void*);
>       if _GLIBCXX17_CONSTEXPR (__lock_free && __double_word && __aligned)
>
>
> But for C++11 and C++14 that is a normal runtime condition not
> if-constexpr, so the undefined shift still gets compiled, even though
> it can never be reached at runtime.

Fixed like so. Tested sparc-sun-solaris2.11, pushed to trunk.