[PATCH] D156778: [SelectionDAG] Improve `isKnownToBeAPowerOfTwo`

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:4078
+
+  Val = PeekThroughCasts(Val);
+
----------------
We can't safely use ANY_EXTEND, afaict you just need this:
```
while (Val.getOpcode() == ISD::ZERO_EXTEND)
  Val = Val.getOperand(0);
```


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D156778/new/

https://reviews.llvm.org/D156778