[Bug bootstrap/69725] LTO/PGO bootstrap fails with in-tree gmp

Sat Oct 21 22:57:00 GMT 2017

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69725

Romain Geissler <romain.geissler at amadeus dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |romain.geissler at amadeus dot com

--- Comment #18 from Romain Geissler <romain.geissler at amadeus dot com> ---
Hi,

This looks like this is a know problem when trying to build GMP with LTO.
Applying the attachment 9 from here:
https://gmplib.org/list-archives/gmp-bugs/2015-June/003691.html will fix the
issue.

In acinclude.m4, gmp tries to detect the endianness of doubles, by analyzing a
raw .o file with awk directly. Obviously an object file with slim LTO won't
look like any normal object file with real assembly, so the test fails during
the second stage ---> the configure script disable the double support.

This seems it was already reported several times on the GMP mailing list, for
example here as well:
https://gmplib.org/list-archives/gmp-bugs/2013-August/003118.html but it seems
to still not be fixed upstream.

Cheers,
Romain