[llvm] Support STRICT_UINT_TO_FP and STRICT_SINT_TO_FP (PR #102503)

[Craig Topper via llvm-commits]

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@@ -6851,30 +6855,35 @@ SDValue RISCVTargetLowering::LowerOperation(SDValue Op,
       return DAG.getNode(ISD::FP_EXTEND, DL, VT, Res);
     return Res;
   }
+  case ISD::STRICT_FP_TO_FP16:
   case ISD::FP_TO_FP16: {
     // Custom lower to ensure the libcall return is passed in an FPR on hard
     // float ABIs.
     assert(Subtarget.hasStdExtFOrZfinx() && "Unexpected custom legalisation");
     SDLoc DL(Op);
     MakeLibCallOptions CallOptions;
-    RTLIB::Libcall LC =
-        RTLIB::getFPROUND(Op.getOperand(0).getValueType(), MVT::f16);
-    SDValue Res =
-        makeLibCall(DAG, LC, MVT::f32, Op.getOperand(0), CallOptions, DL).first;
+    bool IsStrict = Op->isStrictFPOpcode();
+    SDValue Op0 = IsStrict ? Op.getOperand(1) : Op.getOperand(0);
+    RTLIB::Libcall LC = RTLIB::getFPROUND(Op0.getValueType(), MVT::f16);
+    SDValue Res = makeLibCall(DAG, LC, MVT::f32, Op0, CallOptions, DL).first;
     if (Subtarget.is64Bit())
       return DAG.getNode(RISCVISD::FMV_X_ANYEXTW_RV64, DL, MVT::i64, Res);
-    return DAG.getBitcast(MVT::i32, Res);
+    SDValue Result = DAG.getBitcast(MVT::i32, IsStrict ? Res.getValue(0) : Res);
+    if (IsStrict)
+      return DAG.getMergeValues({Result, Op.getOperand(0)}, DL);
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topperc wrote:

We need to return the chain from `makeLibCall.second` here instead of `Op.getOperand(0)`

https://github.com/llvm/llvm-project/pull/102503