http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52299
Bug #: 52299 Summary: GCC warns on compile time division by zero erroneously Classification: Unclassified Product: gcc Version: 4.4.3 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: joseph.h.gar...@gmail.com Test case: template<std::size_t x> struct test { static const std::size_t a_ = x ? 10 / x : 10; }; Output from compiling: alignptrtest.cpp: In instantiation of ‘const size_t test<0ul>::a_’: alignptrtest.cpp:11: instantiated from here alignptrtest.cpp:6: warning: division by zero The warning should be suppressed when zero is explicitly checked for. At runtime this could require fancy analysis that might be unreasonable to expect, but since this is compile time it should be possible to know whether the division by 0 really occurs. Especially since it's smart enough to give the warning even when dividing by (x+1-1).