It doesn't seem like there could be much to say about that. The A structure is 7 bytes long so the subtraction implicitly divides by 7. That's about it. But take a look at the assembly language generated when it's compiled with gcc:
movl 4(%esp), %eax subl 8(%esp), %eax imull $-1227133513, %eax, %eax retWhere is the division by 7? Instead we see multiplication by -1227133513.