GMP test fails with -flto

[Richard Biener]

On Mon, Jul 1, 2019 at 5:27 PM Vincent Lefevre <vincent at vinc17.net> wrote:
>
> On 2019-07-01 16:59:06 +0200, Marc Glisse wrote:
> > On Mon, 1 Jul 2019, Vincent Lefevre wrote:
> > > I suggest another solution:
> > >
> > > First try like now. If the format is unknown, check whether the
> > > object file contains the string ".gnu.lto" (which should mean
> > > that GCC was used with LTO), and in this case, try again with
> > > "-fno-lto" as the patch was doing.
> >
> > We also have problems with clang's version of LTO. IIRC using emscripten to
> > compile GMP has a similar issue.
>
> With clang 7 and above, "ThinLTO" appears in the object file.

-fno-lto also works with clang?

When not cross-compiling the configure test could also be executable
doing the matching itself.  Breaks for cross which is likely why you've
done it as it is now?  For cross-compiling building a shared object
might work though, it should no longer contain only LTO bytecode
but also the data.

Richard.

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