https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91318
Bug ID: 91318 Summary: warnings about unused internal macros with -Wunused-macros and #pragma GCC optimize Product: gcc Version: 10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: phd at phd dot re Target Milestone: --- GCC shows annoying warnings about unused internal macros when using -Wunused-macros parameter to compile code containing #pragma GCC optimize -- a.cpp ----------------------------------------------------------------------- #pragma GCC optimize ("fast-math") #pragma GCC optimize ("finite-math-only") int main() {} -------------------------------------------------------------------------------- command: gcc -Wunused-macros a.cpp -- result ---------------------------------------------------------------------- a.cpp:2:41: warning: macro "__FAST_MATH__" is not used [-Wunused-macros] 2 | #pragma GCC optimize ("finite-math-only") | ^ a.cpp:2:41: warning: macro "__NO_MATH_ERRNO__" is not used [-Wunused-macros] a.cpp:4:13: warning: macro "__FINITE_MATH_ONLY__" is not used [-Wunused-macros] 4 | int main() {} | ^ -------------------------------------------------------------------------------- live demo: https://godbolt.org/z/flbv97