[llvm] [AArch64][GlobalISel] Extend scalar lrint legalization. (PR #88360)

[Matt Arsenault via llvm-commits]

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@@ -1059,6 +1061,26 @@ LegalizerHelper::libcall(MachineInstr &MI, LostDebugLocObserver &LocObserver) {
       return Status;
     break;
   }
+  case TargetOpcode::G_INTRINSIC_LRINT: {
+    LLT LLTy = MRI.getType(MI.getOperand(1).getReg());
+    unsigned Size = LLTy.getSizeInBits();
+    Type *HLTy = getFloatTypeForLLT(Ctx, LLTy);
+    Type *ITy = IntegerType::get(
+        Ctx, MRI.getType(MI.getOperand(0).getReg()).getSizeInBits());
+    if (!HLTy || (Size != 32 && Size != 64 && Size != 80 && Size != 128)) {
+      LLVM_DEBUG(dbgs() << "No libcall available for type " << LLTy << ".\n");
+      return UnableToLegalize;
+    }
+    auto Libcall = getRTLibDesc(MI.getOpcode(), Size);
+    SmallVector<CallLowering::ArgInfo, 2> Args;
+    Args.push_back({MI.getOperand(1).getReg(), HLTy, 0});
+    LegalizeResult Status =
+        createLibcall(MIRBuilder, Libcall, {MI.getOperand(0).getReg(), ITy, 0},
+                      Args, LocObserver, &MI);
+    if (Status != Legalized)
+      return Status;
+    break;
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arsenm wrote:

Erase the instruction and directly return? I don't know why the other cases here are mostly making you look to the end of the function to do the basic return 

https://github.com/llvm/llvm-project/pull/88360