[llvm] [DAG] isKnownToBeAPowerOfTwo - Power of 2 value is known to be power of 2 after BSWAP/BITREVERSE (PR #182207)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

please coordinate with @mirimmad as you seem to be dealing with #182744 as well

https://github.com/llvm/llvm-project/pull/182207