Cedric Berger <cedric at precidata.com> writes: This is a fresh XCode 11.2 (11B52) and Catalina 10.15.1 (19B88) What could I do? Many people are reporting that Catalina's version of clang miscompiles GMP. We don't have any workaround. We generally don't work around compiler bugs. -- Torbjörn Please encrypt, key id 0xC8601622