[PATCH] D128911: Emit table lookup from TargetLowering::expandCTTZ()

[Shubham Narlawar via Phabricator via llvm-commits]

gsocshubham added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp:7840
+  SDValue Neg = DAG.getNode(ISD::SUB, dl, VT, DAG.getConstant(0, dl, VT), Op);
+  SDValue Lookup = DAG.getNode(
+      ISD::SRL, dl, VT,
----------------
dmgreen wrote:
> This needs to be in a `if (NumBitsPerElt == 32 && !VT.isVector())` block. Hopefully with other types available too. Else it would fall back to the existing CTPop. If the CTPOP is legal it is worth using it too, instead of this table lookup.
Done.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D128911/new/

https://reviews.llvm.org/D128911