[RISCV][GISel] Use libcalls for rint, nearbyint, trunc, round, and roundeven intrinsics. (#108779)

Author: topperc

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

@@ -485,6 +485,10 @@ static RTLIB::Libcall getRTLibDesc(unsigned Opcode, unsigned Size) {
     RTLIBCASE(RINT_F);
   case TargetOpcode::G_FNEARBYINT:
     RTLIBCASE(NEARBYINT_F);
+  case TargetOpcode::G_INTRINSIC_TRUNC:
+    RTLIBCASE(TRUNC_F);
+  case TargetOpcode::G_INTRINSIC_ROUND:
+    RTLIBCASE(ROUND_F);
   case TargetOpcode::G_INTRINSIC_ROUNDEVEN:
     RTLIBCASE(ROUNDEVEN_F);
   case TargetOpcode::G_INTRINSIC_LRINT:
@@ -1215,6 +1219,8 @@ LegalizerHelper::libcall(MachineInstr &MI, LostDebugLocObserver &LocObserver) {
   case TargetOpcode::G_FSQRT:
   case TargetOpcode::G_FRINT:
   case TargetOpcode::G_FNEARBYINT:
+  case TargetOpcode::G_INTRINSIC_TRUNC:
+  case TargetOpcode::G_INTRINSIC_ROUND:
   case TargetOpcode::G_INTRINSIC_ROUNDEVEN: {
     LLT LLTy = MRI.getType(MI.getOperand(0).getReg());
     unsigned Size = LLTy.getSizeInBits();

llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp

@@ -541,7 +541,9 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST)
 
   // FIXME: We can do custom inline expansion like SelectionDAG.
   // FIXME: Legal with Zfa.
-  getActionDefinitionsBuilder({G_FCEIL, G_FFLOOR})
+  getActionDefinitionsBuilder({G_FCEIL, G_FFLOOR, G_FRINT, G_FNEARBYINT,
+                               G_INTRINSIC_TRUNC, G_INTRINSIC_ROUND,
+                               G_INTRINSIC_ROUNDEVEN})
       .libcallFor({s32, s64});
 
   getActionDefinitionsBuilder(G_VASTART).customFor({p0});