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From:   Arvind Sankar <nivedita@alum.mit.edu>
Date:   Fri, 21 Aug 2020 15:14:58 -0400
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Arvind Sankar <nivedita@alum.mit.edu>,
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Subject: Re: [PATCH 0/4] -ffreestanding/-fno-builtin-* patches
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On Fri, Aug 21, 2020 at 11:02:08AM -0700, Linus Torvalds wrote:
> On Fri, Aug 21, 2020 at 10:54 AM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > On Fri, Aug 21, 2020 at 10:29 AM Arvind Sankar <nivedita@alum.mit.edu> wrote:
> > >
> > > This is why I'm saying clang's no-builtin-foo option is useful for
> > > embedded: it doesn't prevent the programmer using __builtin_foo(), it
> > > prevents the _compiler_ using __builtin_foo() on its own.
> >
> > And that's fine. But it's apparently not what gcc does.
> 
> Oh, testing it seems to say that that is exactly what gcc does too. I
> must have misunderstood some comment in this thread to mean otherwise.
> 
>                 Linus

How are you testing it?

https://godbolt.org/z/eahdGn