[PATCH] D141990: [InstCombine] Add transform ctpop(X) -> 1 iff X is non-zero power of 2

[David Majnemer via Phabricator via llvm-commits]

majnemer added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp:623-627
 
+  // ctpop(X) -> 1 iff X is non-zero power of 2. Maybe better also to just
+  // return icmp X, 0 if its known power of 2 but not known non-zero.
+  if (IC.isKnownToBeAPowerOfTwo(Op0, /* OrZero */ false))
+    return IC.replaceInstUsesWith(II, ConstantInt::get(Ty, 1));
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Should this be in simplifyIntrinsic?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D141990/new/

https://reviews.llvm.org/D141990