I'm not familiar with that site, I don't see any way of passing arguments to the compiler. To reproduce you have to compile with "-fsanitize=undefined", as in:

I'm not familiar with that site, I don't see any way of passing arguments to the compiler. To reproduce you have to compile with "-fsanitize=undefined", as in: gcc -fsanitize=undefined -o test test.c ./test (clang also works with the exact same command line)