[PATCH] D128583: CodeGen: Remove AliasAnalysis from regalloc

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

The general approach here seems fine.  I suspect we end up calling pointsToConstantMemory for most memory operands at some point anyway.

In general pointsToConstantMemory doesn't imply the pointer is dereferenceable. But in practice, the cases where that happens are probably pretty obscure (like out-of-bounds references to constant arrays).

> I always found it very unfortunate that we keep IR references around in MIR to do alias analysis queries.

I don't really see a good alternative.  Assuming we don't just throw away all alias analysis information, I'm not sure how we'd represent it.  You could try to explicitly construct alias sets during isel, I guess.


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https://reviews.llvm.org/D128583