GMP test fails with -flto

[Martin Liška]

On 7/1/19 6:38 PM, Richard Biener wrote:
> 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.

I like the idea of building a shared library that will work with LTO
as well.

Martin

> 
> Richard.
> 
>> --
>> Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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