[PATCH] D67664: [ARM] Ensure we do not attempt to create lsll #0

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Just to verify the patch is doing what you think it is, you could hack the code.

We don't have any way to write isel tests where the input is a DAG.  You could probably come up with some sequence which currently isn't folded until after type legalization, but it wouldn't really be reliable against future changes to DAG optimizations.  I guess we could introduce an intrinsic that specifically turns into a constant after legalization for testing?  But that's maybe overkill...

Maybe you could actually construct a test using GlobalISel?  GlobalISel is at least partially implemented on ARM, but you'd need to introduce some way to express ARMlsll with GlobalISel, and I'm not sure how to do that, off the top of my head.


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  https://reviews.llvm.org/D67664/new/

https://reviews.llvm.org/D67664