[llvm-branch-commits] [clang] [llvm] [mlir] [polly] [IR] Add alias scope domains with disjoint scopes (PR #218768)

[Bruno De Fraine via llvm-branch-commits]

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brunodf-gf wrote:

This is the core paragraph for noalias semantics, it specifies the noalias constraint for `!alias.scope` and `!noalias` metadata; I really expected you to touch this. Instead, you define the effect of domains with disjoint scopes through implicit entries in the `noalias` list below. This is perhaps fine, but:

* This specification does not match the implementation in ScopedNoAliasAA, where it is rather like an _additional_ noalias constraint for distinct scope domains (i.e. `mayAliasInDisjointDomains` is entirely separate from `mayAliasInScopes`). I think it would be better if the specification and implementation lined up directly, for example, if you specified the additional noalias constraint that you implement in `mayAliasInDisjointDomains` directly here.
* If you decide to keep the specification with implicit entries in the `noaliast` list, you should at least forward-reference the disjoint scope domains here, maybe just by stating that the entries in the `noalias` list can also be implicit through distinct scope domains?

https://github.com/llvm/llvm-project/pull/218768