foo.cc:11:30: warning: ‘-std=c++11’ is not an option that controls warnings [-Wpragmas]
   11 | #pragma GCC diagnostic error "-std=c++11"
      |                              ^~~~~~~~~~~~
foo.cc:33:39: warning: bad option ‘-fwhole-program’ to pragma ‘optimize’ [-Wpragmas]
   33 | #pragma GCC optimize("-fwhole-program")
      |                                       ^
foo.cc:40:41: warning: bad option ‘-fstrict-overflow’ to pragma ‘optimize’ [-Wpragmas]
   40 | #pragma GCC optimize("-fstrict-overflow")
      |                                         ^
foo.cc:42:41: warning: bad option ‘-fcse-skip-blocks’ to pragma ‘optimize’ [-Wpragmas]
   42 | #pragma GCC optimize("-fcse-skip-blocks")
      |                                         ^
foo.cc:56:51: warning: bad option ‘-funsafe-loop-optimizations’ to pragma ‘optimize’ [-Wpragmas]
   56 | #pragma GCC optimize("-funsafe-loop-optimizations")
      |                                                   ^
foo.cc:61:10: warning: bad option ‘-fwhole-program’ to attribute ‘optimize’ [-Wattributes]
   61 | int main(){
      |          ^
foo.cc:61:10: warning: bad option ‘-fstrict-overflow’ to attribute ‘optimize’ [-Wattributes]
foo.cc:61:10: warning: bad option ‘-fcse-skip-blocks’ to attribute ‘optimize’ [-Wattributes]
foo.cc:61:10: warning: bad option ‘-funsafe-loop-optimizations’ to attribute ‘optimize’ [-Wattributes]