http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48933
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-05-09 10:46:40 UTC --- Yes, we should disable the TR1 math functions for anything that isn't integral or floating point, because it happens with any non-integral, non-float type: #include <tr1/cmath> struct Foo { }; int main() { std::tr1::acosh( Foo() ); }