[SDAG] Pass pointer type to libcall expansion for SoftenFloatRes stack slots

Solution for: llvm#129264 (comment)

Author: MacDue

llvm/include/llvm/CodeGen/TargetLowering.h

@@ -4749,6 +4749,8 @@ class TargetLowering : public TargetLoweringBase {
     // shouldExtendTypeInLibCall can get the original type before soften.
     ArrayRef<EVT> OpsVTBeforeSoften;
     EVT RetVTBeforeSoften;
+    ArrayRef<Type *> OpsTypeOverrides;
+
     bool IsSigned : 1;
     bool DoesNotReturn : 1;
     bool IsReturnValueUsed : 1;
@@ -4786,6 +4788,13 @@ class TargetLowering : public TargetLoweringBase {
       IsSoften = Value;
       return *this;
     }
+
+    /// Override the argument type for an operand. Leave the type as null to use
+    /// the type from the operand's node.
+    MakeLibCallOptions &setOpsTypeOverrides(ArrayRef<Type *> OpsTypes) {
+      OpsTypeOverrides = OpsTypes;
+      return *this;
+    }
   };
 
   /// This function lowers an abstract call to a function into an actual call.

llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

@@ -772,13 +772,16 @@ SDValue DAGTypeLegalizer::SoftenFloatRes_FFREXP(SDNode *N) {
 
   SDLoc DL(N);
 
+  auto PointerTy = PointerType::getUnqual(*DAG.getContext());
   TargetLowering::MakeLibCallOptions CallOptions;
   SDValue Ops[2] = {GetSoftenedFloat(N->getOperand(0)), StackSlot};
   EVT OpsVT[2] = {VT0, StackSlot.getValueType()};
+  Type* CallOpsTypeOverrides[2] = { nullptr, PointerTy };
 
   // TODO: setTypeListBeforeSoften can't properly express multiple return types,
   // but we only really need to handle the 0th one for softening anyway.
-  CallOptions.setTypeListBeforeSoften({OpsVT}, VT0, true);
+  CallOptions.setTypeListBeforeSoften({OpsVT}, VT0, true)
+    .setOpsTypeOverrides(CallOpsTypeOverrides);
 
   auto [ReturnVal, Chain] = TLI.makeLibCall(DAG, LC, NVT0, Ops, CallOptions, DL,
                                             /*Chain=*/SDValue());
@@ -811,19 +814,23 @@ SDValue DAGTypeLegalizer::SoftenFloatRes_UnaryWithTwoFPResults(
   SmallVector<EVT, 3> OpsVT = {VT};
 
   std::array<SDValue, 2> StackSlots;
+  SmallVector<Type *, 3> CallOpsTypeOverrides = {nullptr};
+  auto PointerTy = PointerType::getUnqual(*DAG.getContext());
   for (unsigned ResNum = 0; ResNum < N->getNumValues(); ++ResNum) {
     if (ResNum == CallRetResNo)
       continue;
     SDValue StackSlot = DAG.CreateStackTemporary(NVT);
     Ops.push_back(StackSlot);
     OpsVT.push_back(StackSlot.getValueType());
     StackSlots[ResNum] = StackSlot;
+    CallOpsTypeOverrides.push_back(PointerTy);
   }
 
   TargetLowering::MakeLibCallOptions CallOptions;
   // TODO: setTypeListBeforeSoften can't properly express multiple return types,
   // but since both returns have the same type it should be okay.
-  CallOptions.setTypeListBeforeSoften({OpsVT}, VT, true);
+  CallOptions.setTypeListBeforeSoften({OpsVT}, VT, true)
+      .setOpsTypeOverrides(CallOpsTypeOverrides);
 
   auto [ReturnVal, Chain] = TLI.makeLibCall(DAG, LC, NVT, Ops, CallOptions, DL,
                                             /*Chain=*/SDValue());

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -157,10 +157,13 @@ TargetLowering::makeLibCall(SelectionDAG &DAG, RTLIB::Libcall LC, EVT RetVT,
   Args.reserve(Ops.size());
 
   TargetLowering::ArgListEntry Entry;
+  ArrayRef<Type *> OpsTypeOverrides = CallOptions.OpsTypeOverrides;
   for (unsigned i = 0; i < Ops.size(); ++i) {
     SDValue NewOp = Ops[i];
     Entry.Node = NewOp;
-    Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
+    Entry.Ty = i < OpsTypeOverrides.size() && OpsTypeOverrides[i]
+                   ? OpsTypeOverrides[i]
+                   : Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
     Entry.IsSExt =
         shouldSignExtendTypeInLibCall(Entry.Ty, CallOptions.IsSigned);
     Entry.IsZExt = !Entry.IsSExt;