[RISCV] Expand scalable vector CTTZ/CTLZ/CTPOP.

Differential Revision: https://reviews.llvm.org/D112233

Author: topperc

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -533,6 +533,10 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
       setOperationAction(ISD::ROTL, VT, Expand);
       setOperationAction(ISD::ROTR, VT, Expand);
 
+      setOperationAction(ISD::CTTZ, VT, Expand);
+      setOperationAction(ISD::CTLZ, VT, Expand);
+      setOperationAction(ISD::CTPOP, VT, Expand);
+
       // Custom-lower extensions and truncations from/to mask types.
       setOperationAction(ISD::ANY_EXTEND, VT, Custom);
       setOperationAction(ISD::SIGN_EXTEND, VT, Custom);