[CostModel/RISCV] Fix costs of [l]lrint, [l]lround

Author: artagnon

llvm/include/llvm/CodeGen/BasicTTIImpl.h

@@ -2290,6 +2290,12 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
     case Intrinsic::llrint:
       ISD = ISD::LLRINT;
       break;
+    case Intrinsic::lround:
+      ISD = ISD::LROUND;
+      break;
+    case Intrinsic::llround:
+      ISD = ISD::LLROUND;
+      break;
     case Intrinsic::round:
       ISD = ISD::FROUND;
       break;

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

@@ -1191,9 +1191,6 @@ static const CostTblEntry VectorIntrinsicCostTable[]{
     {Intrinsic::roundeven, MVT::f64, 9},
     {Intrinsic::rint, MVT::f32, 7},
     {Intrinsic::rint, MVT::f64, 7},
-    {Intrinsic::lrint, MVT::i32, 1},
-    {Intrinsic::lrint, MVT::i64, 1},
-    {Intrinsic::llrint, MVT::i64, 1},
     {Intrinsic::nearbyint, MVT::f32, 9},
     {Intrinsic::nearbyint, MVT::f64, 9},
     {Intrinsic::bswap, MVT::i16, 3},
@@ -1262,11 +1259,29 @@ RISCVTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
   switch (ICA.getID()) {
   case Intrinsic::lrint:
   case Intrinsic::llrint:
-    // We can't currently lower half or bfloat vector lrint/llrint.
-    if (auto *VecTy = dyn_cast<VectorType>(ICA.getArgTypes()[0]);
-        VecTy && VecTy->getElementType()->is16bitFPTy())
-      return InstructionCost::getInvalid();
-    [[fallthrough]];
+  case Intrinsic::lround:
+  case Intrinsic::llround: {
+    auto LT = getTypeLegalizationCost(RetTy);
+    switch (ICA.getID()) {
+    case Intrinsic::lrint:
+    case Intrinsic::llrint:
+      // We can't currently lower half or bfloat vector lrint/llrint.
+      if (auto *VecTy = dyn_cast<VectorType>(ICA.getArgTypes()[0]);
+          VecTy && VecTy->getElementType()->is16bitFPTy())
+        return InstructionCost::getInvalid();
+      break;
+    case Intrinsic::lround:
+    case Intrinsic::llround:
+      // We can't currently lower scalable-vector lround/llround.
+      if (LT.second.isScalableVector())
+        return InstructionCost::getInvalid();
+      break;
+    }
+    if (ST->hasVInstructions() && LT.second.isVector())
+      return LT.first *
+             getRISCVInstructionCost(RISCV::VFCVT_X_F_V, LT.second, CostKind);
+    break;
+  }
   case Intrinsic::ceil:
   case Intrinsic::floor:
   case Intrinsic::trunc: