If you compile the following program with Optimizations set to None,
struct foo_s { int i;} *b[9], *c;
int main(int argc, char *argv[]) { int x = c - b[c->i];}
set a breakpoint on the 2d line and Show Dissasembly in the debugger, you see the compiler generated the following code:
...
mov eax, dword ptr [c]
mov eax, dword ptr [eax]
mov eax, dword ptr [eax*4+b] <=== Oops, this should be a "mov edx, ..."
sub eax, eax <=== Oops, this is always 0, should be "sub edx, eax"
sar eax, 2
mov dword ptr
...
Breaking the expression up and storing c->i in a temp is a workaround, but compiler bugs are scary...
