[SelectionDAG][RISCV] Use FP type for legality query for LRINT/LLRINT in LegalizeVectorOps. (llvm#82728)

This matches how LRINT/LLRINT is queried for scalar types in
LegalizeDAG.

It's confusing if they do different things since a "Legal" vector
LRINT/LLRINT would get through to LegalizeDAG which would then consider
it illegal. This doesn't happen currently because RISC-V uses Custom.

Author: topperc

llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp

@@ -404,8 +404,6 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
   case ISD::FCEIL:
   case ISD::FTRUNC:
   case ISD::FRINT:
-  case ISD::LRINT:
-  case ISD::LLRINT:
   case ISD::FNEARBYINT:
   case ISD::FROUND:
   case ISD::FROUNDEVEN:
@@ -455,6 +453,8 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
                                               Node->getValueType(0), Scale);
     break;
   }
+  case ISD::LRINT:
+  case ISD::LLRINT:
   case ISD::SINT_TO_FP:
   case ISD::UINT_TO_FP:
   case ISD::VECREDUCE_ADD:

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -830,7 +830,6 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
                          VT, Custom);
       setOperationAction({ISD::FP_TO_SINT_SAT, ISD::FP_TO_UINT_SAT}, VT,
                          Custom);
-      setOperationAction({ISD::LRINT, ISD::LLRINT}, VT, Custom);
       setOperationAction({ISD::AVGFLOORU, ISD::AVGCEILU, ISD::SADDSAT,
                           ISD::UADDSAT, ISD::SSUBSAT, ISD::USUBSAT},
                          VT, Legal);
@@ -956,6 +955,7 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
       // between vXf16 and vXf64 must be lowered as sequences which convert via
       // vXf32.
       setOperationAction({ISD::FP_ROUND, ISD::FP_EXTEND}, VT, Custom);
+      setOperationAction({ISD::LRINT, ISD::LLRINT}, VT, Custom);
       // Custom-lower insert/extract operations to simplify patterns.
       setOperationAction({ISD::INSERT_VECTOR_ELT, ISD::EXTRACT_VECTOR_ELT}, VT,
                          Custom);