Add missing GVN =operator. NFCI.

Fixes PVS Studio warning that the 'ValueTable' class implements a copy constructor, but lacks the '=' operator.

Author: RKSimon

llvm/include/llvm/Transforms/Scalar/GVN.h

@@ -130,6 +130,7 @@ class GVN : public PassInfoMixin<GVN> {
     ValueTable(const ValueTable &Arg);
     ValueTable(ValueTable &&Arg);
     ~ValueTable();
+    ValueTable &operator=(const ValueTable &Arg);
 
     uint32_t lookupOrAdd(Value *V);
     uint32_t lookup(Value *V, bool Verify = true) const;

llvm/lib/Transforms/Scalar/GVN.cpp

@@ -364,6 +364,7 @@ GVN::ValueTable::ValueTable() = default;
 GVN::ValueTable::ValueTable(const ValueTable &) = default;
 GVN::ValueTable::ValueTable(ValueTable &&) = default;
 GVN::ValueTable::~ValueTable() = default;
+GVN::ValueTable &GVN::ValueTable::operator=(const GVN::ValueTable &Arg) = default;
 
 /// add - Insert a value into the table with a specified value number.
 void GVN::ValueTable::add(Value *V, uint32_t num) {