View Compilation Error

0_0_39626694_2001.cpp:10:16: error: size of array 'sum' is not an integral constant-expression
   10 | int sum[n<<2][m<<2];
      |               ~^~~
0_0_39626694_2001.cpp:10:10: error: size of array 'sum' is not an integral constant-expression
   10 | int sum[n<<2][m<<2];
      |         ~^~~