[PATCH] D35035: [InstCombine] Prevent memcpy generation for small data size

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

> The ultimate goal would be to simply always canonicalize to memcpy and not expand it ever in instcombine as mentioned in https://reviews.llvm.org/D52081.

Looks like we all agree on this now.

> But we don't do that (yet) because we're afraid of missed optimizations that can't be replicated in the backend.

Perhaps the impact is negligible, non-existent, and we worry about this for nothing. As also suggested earlier, I will try to get some numbers on the table for ARM and AArch64 if we strip out the lowering here, if that is helpful for this discussion, but probably need a day or two to get them.


https://reviews.llvm.org/D35035