https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67824
--- Comment #1 from Erich Keane <erich.keane at intel dot com> --- I just reconfirmed this in 5.3.1 on Fedora: gcc (GCC) 5.3.1 20151207 (Red Hat 5.3.1-2) Copyright (C) 2015 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Error message for the previous example is: constexpr_gcc_bug.cpp: In function βint main()β: constexpr_gcc_bug.cpp:8:5: error: non-constant condition for static assertion static_assert(root2 < root2 + 1, "This fails"); ^ constexpr_gcc_bug.cpp:8:25: error: β(((const char*)"12") < (((const char*)"12") + 1u))β is not a constant expression static_assert(root2 < root2 + 1, "This fails");