Hello, i worked with g++ 4.3.1 (linux/586) and experienced some aliasing issues. Basically, i have a base class and an derived class and i am doing downcasts in a number of places using static_cast<derived*>(base_pointer) (no other casting is involved, except implicit casting from derived* to base*). To my understanding, this should not be a problem, since both types are related. Nevertheless, using -O2 or -O3 resulted in broken code. Apparently the order of execution was mixed up in some places. Using -fno-strict-aliasing or applying the may_alias attribute to these classes resolved the problem. The whole issue is very hard to reproduce, so i could not boil it down to a simple example (as the optimizer propably acts very unpredictable on different code). I did not have this problem using some GCC 4.1 and 4.2. I just upgraded to 4.3.3 and the problem vanished again. Nevertheless, i am worried the bug just *happens* to not show up, because the optimizer may work a little different. So: are there any aliasing issues that are known to be explicitly resolved by 4.3.3?
