GMP test fails with -flto

[Marc Glisse]

On Mon, 1 Jul 2019, Vincent Lefevre wrote:

> On 2019-07-01 13:44:04 +0200, Marc Glisse wrote:
>> On Mon, 1 Jul 2019, Martin Liška wrote:
>> 
>> > On 6/24/19 8:57 PM, Marc Glisse wrote:
>> > > On Mon, 24 Jun 2019, Martin Liška wrote:
>> > > 
>> > > > Using -flto one can see a test failure:
>> > > 
>> > > This is well known, see the archives for details. It is a combination of 2 issues:
>> > > - (thin) LTO prevents configure from guessing the floating point format
>> > > - a bug in the generic GMP code (fixed in master IIRC)
>> > > 
>> > 
>> > Hi.
>> > 
>> > I've got a patch for the wrong configure of floating point format.
>> 
>> That's going to break every non-gcc compiler, isn't it?
>
> 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.

-- 
Marc Glisse