[PATCH] D104801: [MemCpyOpt] Enable memcpy optimizations unconditionally.

[Artem Belevich via Phabricator via llvm-commits]

tra added a comment.

In D104801#2889283 <https://reviews.llvm.org/D104801#2889283>, @hgreving wrote:

> Besides that this patch created the intrinsics llvm.memset which in our target was unsupported, it also created pointers that may be invalid on the target, e.g. i8 addrspace(X)* where addrspace(X) only supports vector memory. While this is probably all solvable, please consider adding TTI switches for targets to disable this optimization (e.g. for the intrinsics).

...and that brings us back to where this patch has started -- with a TTI knob to control whether it wants this pass enabled. :-/

That said, I'm not quite sure that "this type/AS combination" is invalid is something you can expect all parts of LLVM to respect. While this pass may happen to tickle it, I can see other cases where the type of the pointer may change. I would think that dealing with the quirks of type support of particular target  would be something for legalizer to do.


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https://reviews.llvm.org/D104801