https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77656
Bug ID: 77656 Summary: 64-bit integral template parameter gets incorrectly sized as 32-bits Product: gcc Version: 6.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: matt at matthewfagan dot com Target Milestone: --- GCC incorrectly sizes 64-bit integer template parameters, resulting in spurious warnings (and perhaps incorrect code generation - unable to test this part). The following sample code demonstrates the error: (Compiled for Target: x86_64-pc-linux-gnu) #include <stdint.h> template< uint64_t _Val, int _Val2 = (_Val >> 32) > class Test { }; template<uint32_t _X> class Test2 : Test<_X> {}; template<uint32_t _X> class Test3 : Test<(uint64_t) _X> {}; Upon compilation, Test2 produces a spurious warning, but Test3 does not.