[PATCH] D149196: [SelectionDAG] Use `computeKnownBits` if `Op` is not recognized by `isKnownNeverZero`

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:5020
 
-  return false;
+  return !computeKnownBits(Op, Depth - 1).One.isZero();
 }
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foad wrote:
> craig.topper wrote:
> > `return computeKnownBits(Op, Depth - 1).isNonZero()`. KnownBits already has a wrapper so we don't have to reference the `One` field directly.
> It would be less confusing overall to *not* increment Depth.
I think in this case is but it makes it so that in all the recursive cases you can just copy `Depth` rather than `Depth + 1`. Its also what we do in `ValueTracking` to think it makes sense to keep it similiar.


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  https://reviews.llvm.org/D149196/new/

https://reviews.llvm.org/D149196