foo.cc:21:39: warning: bad option '-fwhole-program' to pragma 'optimize' [-Wpragmas]
   21 | #pragma GCC optimize("-fwhole-program")
      |                                       ^
foo.cc:28:41: warning: bad option '-fstrict-overflow' to pragma 'optimize' [-Wpragmas]
   28 | #pragma GCC optimize("-fstrict-overflow")
      |                                         ^
foo.cc:30:41: warning: bad option '-fcse-skip-blocks' to pragma 'optimize' [-Wpragmas]
   30 | #pragma GCC optimize("-fcse-skip-blocks")
      |                                         ^
foo.cc:44:51: warning: bad option '-funsafe-loop-optimizations' to pragma 'optimize' [-Wpragmas]
   44 | #pragma GCC optimize("-funsafe-loop-optimizations")
      |                                                   ^
foo.cc:56:17: warning: bad option '-fwhole-program' to attribute 'optimize' [-Wattributes]
   56 | void xorshift64() {
      |                 ^
foo.cc:56:17: warning: bad option '-fstrict-overflow' to attribute 'optimize' [-Wattributes]
foo.cc:56:17: warning: bad option '-fcse-skip-blocks' to attribute 'optimize' [-Wattributes]
foo.cc:56:17: warning: bad option '-funsafe-loop-optimizations' to attribute 'optimize' [-Wattributes]
foo.cc:63:14: warning: bad option '-fwhole-program' to attribute 'optimize' [-Wattributes]
   63 | void workfst() {
      |              ^
foo.cc:63:14: warning: bad option '-fstrict-overflow' to attribute 'optimize' [-Wattributes]
foo.cc:63:14: warning: bad option '-fcse-skip-blocks' to attribute 'optimize' [-Wattributes]
foo.cc:63:14: warning: bad option '-funsafe-loop-optimizations' to attribute 'optimize' [-Wattributes]
foo.cc:110:13: warning: bad option '-fwhole-program' to attribute 'optimize' [-Wattributes]
  110 | signed main() {
      |             ^
foo.cc:110:13: warning: bad option '-fstrict-overflow' to attribute 'optimize' [-Wattributes]
foo.cc:110:13: warning: bad option '-fcse-skip-blocks' to attribute 'optimize' [-Wattributes]
foo.cc:110:13: warning: bad option '-funsafe-loop-optimizations' to attribute 'optimize' [-Wattributes]
foo.cc: In function 'int main()':
foo.cc:111:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  111 |  freopen("walk.in", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
foo.cc:112:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  112 |  freopen("walk.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:130:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  130 |   scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Found 10 testcases.