foo.cc:22:39: warning: bad option '-fwhole-program' to pragma 'optimize' [-Wpragmas]
   22 | #pragma GCC optimize("-fwhole-program")
      |                                       ^
foo.cc:29:41: warning: bad option '-fstrict-overflow' to pragma 'optimize' [-Wpragmas]
   29 | #pragma GCC optimize("-fstrict-overflow")
      |                                         ^
foo.cc:31:41: warning: bad option '-fcse-skip-blocks' to pragma 'optimize' [-Wpragmas]
   31 | #pragma GCC optimize("-fcse-skip-blocks")
      |                                         ^
foo.cc:45:51: warning: bad option '-funsafe-loop-optimizations' to pragma 'optimize' [-Wpragmas]
   45 | #pragma GCC optimize("-funsafe-loop-optimizations")
      |                                                   ^
foo.cc:53:15: warning: bad option '-fwhole-program' to attribute 'optimize' [-Wattributes]
   53 | void DFS(int X)
      |               ^
foo.cc:53:15: warning: bad option '-fstrict-overflow' to attribute 'optimize' [-Wattributes]
foo.cc:53:15: warning: bad option '-fcse-skip-blocks' to attribute 'optimize' [-Wattributes]
foo.cc:53:15: warning: bad option '-funsafe-loop-optimizations' to attribute 'optimize' [-Wattributes]
foo.cc:83:10: warning: bad option '-fwhole-program' to attribute 'optimize' [-Wattributes]
   83 | int main()
      |          ^
foo.cc:83:10: warning: bad option '-fstrict-overflow' to attribute 'optimize' [-Wattributes]
foo.cc:83:10: warning: bad option '-fcse-skip-blocks' to attribute 'optimize' [-Wattributes]
foo.cc:83:10: warning: bad option '-funsafe-loop-optimizations' to attribute 'optimize' [-Wattributes]

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