[PATCH] D117983: [DAG] Fold (X & Y) != 0 --> zextOrTrunc(X & Y) iff everything but LSB is known zero (PR51312)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp:3273-3274
+    APInt UpperBits = APInt::getHighBitsSet(NumEltBits, NumEltBits - 1);
+    if (DAG.MaskedValueIsZero(N0, UpperBits))
+      return DAG.getZExtOrTrunc(N0, DL, VT);
+  }
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lebedev.ri wrote:
> ?
SGTM - cheers


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  https://reviews.llvm.org/D117983/new/

https://reviews.llvm.org/D117983