This would entirely lose the benefit I discussed above of making pointer-integer round-trips a *local* concern -- if these round-trips produce new, never-before-seen kinds of provenance, then the entire rest of the memory model has to define how it deals with those provenances.
We already have no choice but treat pointer-integer casts as an operation with side-effects; let's just do the same with integer-pointer casts and remain sure that no matter what the aliasing rules are, they will work fine even in the presence of pointer-integer round-trips.
+That said, under this model integer-pointer casts still have no side-effect, in the sense that just removing them (if their result is unused) is fine.
+Hence, it *could* make sense to implicitly perform integer-pointer casts in some situations, like when an integer value (without provenance) is used in a pointer operation (due to an integer-to-pointer transmutation).
+This breaks some optimizations like load fusion (turning two loads into one assumes the same provenance was picked both times), but most optimizations (in particular dead code elimination) are unaffected.
+
#### What about LLVM?
I discussed above how my vision for Rust relates to the direction C is moving towards.
projects / web.git / blobdiff