[PATCH] Clarify wording in the LangRef around !invariant.load

[Sanjoy Das]

> To clarify that the invariant nature of a given pointer does not preclude the modification of that location through a pointer which is unrelated to the load operand. In particular, initializing a location and then passing a pointer through an opaque intrinsic which produces a new unrelated pointer, should behave as expected provided that the intrinsic is memory dependent on the initializing store.

Does this mean you cannot common loads for escaped memory over calls?  The call could have modified the pointed-to location using another pointer.

http://reviews.llvm.org/D6346