https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67728
--- Comment #12 from Bernd Edlinger <bernd.edlinger at hotmail dot de> --- It is on purpose that the in-tree gmp is configured to use no assembly, but the in-tree configuration does not really work with gmp-6.1.0, and apparently disables the assembly only half-way. It is not possible to fix that without breaking compatibility to gmp-4.3.2 at the same time. I fully agree that it is time to move to a new gmp version for gcc-7, but if we do so we will also require a specific mpfr and mpc version too. And from the experience in the past, I would bet that you will not be able to simply use any future gmp version, without very careful testing, and updating mpfr and mpc to compatible versions at the same time. As a matter of fact, even when not building in-tree, there are often incompatibilities: For instance mpfr-2.4.2/INSTALL says: 0. You first need to install GMP. See <http://www.gnu.org/software/gmp/>. MPFR requires GMP version 4.1 or later. And gmp-6.1.0/INSTALL does not mention MPFR at all. But building mpfr-2.4.2 with gmp-6.1.0 fails. For instance mpc-0.8.1/INSTALL says: 0. You first need to install GMP and MPFR. See <http://gmplib.org/> and <http://www.mpfr.org>. MPC requires GMP version 4.2 or later and MPFR version 2.3.1 or later. And again mpfr-3.1.3/INSTALL does not mention MPC at all. But building mpc-0.8.1 with gmp-6.1.0 and mpfr-3.1.3 fails. So it is simply impossible to give any guarantees of that kind. All we can do is update to a specific gmp/mpfr/mpc version, and guarantee that exactly that combination will actually work.
