> In non-LTO compilation I think it would allows us to optimize bettter in the > case address of the global symbol can not be taken by the other unit or it > can not escape back to current unit. For C/C++ this would be for runtime > generates symbols, like for gcov runtime (well if our initialization was > not implemented in a way taking address of everything). For non-C languages > I expect there are cases where you just can't take address of a given > object.
Yes, that's true in Ada :-), at least theoritically since you need to explicitly mark objects with "aliased" to be able to take their address. > For LTO compilation this is useful for optimizing cases where variable is > static at whole program optimization time, but it becomes hidden by > partitioning and at whole program time we figure out its address is not > taken. Then why not just make the LTO front-end follow the existing semantics of TREE_ADDRESSABLE and clear it when it figures out that the address is not taken? That would seem the natural thing to do here. -- Eric Botcazou
