### Compilation failed:

error: 3: discard statement is only permitted in fragment shaders
void discard_stmt() { discard; }
                      ^^^^^^^
error: 5: do-while loops are not supported
int do_loop(int x) { do { x++; } while(x < 1); return x; }
                     ^^^^^^^^^^^^^^^^^^^^^^^^^
error: 7: while loops are not supported
int while_loop(int x) { while (x < 1) { x++; } return x; }
                        ^^^^^^^^^^^^^^^^^^^^^^
3 errors