In the attached C program, passing a double and a struct-with-two-doubles to a function causes the struct's second field to get the same value as the struct's first field. The expected behavior for the program, which works in both GCC and Clang, is to print "Starting with (123,456) we get (123,456)", but when compiled with TCC, it prints "Starting with (123,456) we get (123,123)". The issue goes away if the first argument is not a float or a double.