[NFC] make TypeInfer::MergeInTypeInfo const

[craig.topper]

LGTM

llvm/utils/TableGen/CodeGenDAGPatterns.h

ValueTypeByHwMode getConcrete(const TypeSetByHwMode &VTS,
     assert(VTS.isValueTypeByHwMode(AllowEmpty));
     return VTS.getValueTypeByHwMode();
   }
 
   /// The protocol in the following functions (Merge*, force*, Enforce*,
   /// expand*) is to return "true" if a change has been made, "false"
   /// otherwise.
 
-  bool MergeInTypeInfo(TypeSetByHwMode &Out, const TypeSetByHwMode &In);
-  bool MergeInTypeInfo(TypeSetByHwMode &Out, MVT::SimpleValueType InVT) {
+  bool MergeInTypeInfo(TypeSetByHwMode &Out, const TypeSetByHwMode &In) const;
+  bool MergeInTypeInfo(TypeSetByHwMode &Out, MVT::SimpleValueType InVT) const {
     return MergeInTypeInfo(Out, TypeSetByHwMode(InVT));
   }
-  bool MergeInTypeInfo(TypeSetByHwMode &Out, ValueTypeByHwMode InVT) {
+  bool MergeInTypeInfo(TypeSetByHwMode &Out, ValueTypeByHwMode InVT) const {
     return MergeInTypeInfo(Out, TypeSetByHwMode(InVT));
   }
 
   /// Reduce the set \p Out to have at most one element for each mode.
   bool forceArbitrary(TypeSetByHwMode &Out);
 
   /// The following four functions ensure that upon return the set \p Out
   /// will only contain types of the specified kind: integer, floating-point,
struct TypeInfer {
 
   /// For each overloaded type (i.e. of form *Any), replace it with the
   /// corresponding subset of legal, specific types.
   void expandOverloads(TypeSetByHwMode &VTS);
   void expandOverloads(TypeSetByHwMode::SetType &Out,
                        const TypeSetByHwMode::SetType &Legal);
 
   struct ValidateOnExit {
-    ValidateOnExit(TypeSetByHwMode &T, TypeInfer &TI) : Infer(TI), VTS(T) {}
+    ValidateOnExit(const TypeSetByHwMode &T, const TypeInfer &TI)
+        : Infer(TI), VTS(T) {}
     ~ValidateOnExit();
-    TypeInfer &Infer;
-    TypeSetByHwMode &VTS;
+    const TypeInfer &Infer;
+    const TypeSetByHwMode &VTS;
   };
 
   struct SuppressValidation {
     SuppressValidation(TypeInfer &TI) : Infer(TI), SavedValidate(TI.Validate) {
       Infer.Validate = false;
     }
     ~SuppressValidation() {
       Infer.Validate = SavedValidate;

llvm/utils/TableGen/CodeGenDAGPatterns.cpp

bool TypeSetByHwMode::validate() const {
   for (const auto &I : *this)
     AllEmpty &= I.second.empty();
   return !AllEmpty;
 }
 
 // --- TypeInfer
 
 bool TypeInfer::MergeInTypeInfo(TypeSetByHwMode &Out,
-                                const TypeSetByHwMode &In) {
+                                const TypeSetByHwMode &In) const {
   ValidateOnExit _1(Out, *this);
   In.validate();
   if (In.empty() || Out == In || TP.hasError())
     return false;
   if (Out.empty()) {
     Out = In;
     return true;
   }