[PATCH] D153148: [InstCombine] Fold `(-1 + A) & B` into `A ? 0 : B` where A is effectively a bool

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:2609
+      return SelectInst::Create(A, Constant::getNullValue(Ty), B);
+    if (computeKnownBits(A, /* Depth */ 0, &I).countMaxActiveBits() <= 1) {
+      return SelectInst::Create(
----------------
`computeKnownBits(A, /* Depth */ 0, &I).countMaxActiveBits() <= 1` -> `isKnownToBeAPowerOfTwo(A,..., /*OrZero*/true, ...)`


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D153148/new/

https://reviews.llvm.org/D153148