https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93324
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:15ed55eabb0cf8a2974b8025a9f46c9e58960811 commit r10-6148-g15ed55eabb0cf8a2974b8025a9f46c9e58960811 Author: Marek Polacek <pola...@redhat.com> Date: Wed Jan 22 11:44:13 2020 -0500 PR c++/93324 - ICE with -Wall on constexpr if. This is a crash with constexpr if, when trying to see if the call in the if-statement is std::is_constant_evaluated. cp_get_callee_fndecl_nofold can return NULL_TREE and fndecl_built_in_p doesn't expect to get a null tree, so check FNDECL first.