[llvm] r255334 - [InstCombine] Make MatchBSwap also match bit reversals

Joerg Sonnenberger via llvm-commits llvm-commits at lists.llvm.org
Thu Dec 24 14:53:18 PST 2015

On Thu, Dec 24, 2015 at 10:36:16PM +0000, James Molloy wrote:
> I'm not sure I understand the test case I'm afraid- that's only 32
> operations to look through ... What am I missing?

I think the combination of "or" and "shift" forces the deep recursion.
Note that this is a common avalanche pattern for ctz. I'm bit a
surprised we haven't hit it earlier.


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