Wow, thank you all, you guys!

在 2024年3月14日星期四，Jonathan Wakely <jwakely@redhat.com> 写道：

> On Fri, 16 Feb 2024 at 15:15, Jonathan Wakely wrote:
> >
> > On Fri, 16 Feb 2024 at 14:10, Jakub Jelinek wrote:
> > >
> > > On Fri, Feb 16, 2024 at 01:51:54PM +0000, Jonathan Wakely wrote:
> > > > Ah, although __atomic_compare_exchange only takes pointers, the
> > > > compiler replaces that with a call to __atomic_compare_exchange_n
> > > > which takes the newval by value, which presumably uses an 80-bit FP
> > > > register and so the padding bits become indeterminate again.
> > >
> > > __atomic_compare_exchange_n only works with integers, so I guess
> > > it is doing VIEW_CONVERT_EXPR (aka union-style type punning) on the
> > > argument.
> > >
> > > Do you have preprocessed source for the testcase?
> >
> > Sent offlist.
>
> Jakub fixed the compiler, so I've pushed the attached patch now.
>
> Tested x86_64-linux.
>