[PATCH] D151449: [RISCV] Add DAG combine for CTTZ/CTLZ in the case of input 0

[Alex Bradbury via Phabricator via llvm-commits]

asb added a comment.

Just some feedback on the test case:

- It doesn't show up in for RV64ZBB, but best to add the `nounwind` attribute for all functions
- You should have an RV32ZBB RUN line too
- I believe codegen differences are also visible for some of these tests without zbb, which I think is a good reason for including baseline RV32I and RV64I RUN lines too (and these will have unwanted `.cfi_*` noise if you don't add `nounwind`).


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  https://reviews.llvm.org/D151449/new/

https://reviews.llvm.org/D151449