Subzero. Fixes memory leaks.

src/IceOperand.h

Index: src/IceOperand.h
diff --git a/src/IceOperand.h b/src/IceOperand.h
index 4ae217c5f3b36676469e1dd635920ecd0d1e0704..f5e39ffc04f3b7348274f648668021e882de9ea1 100644
--- a/src/IceOperand.h
+++ b/src/IceOperand.h
@@ -79,8 +79,6 @@ public:
       dump(nullptr, Str);
   }
 
-  virtual ~Operand() {}
-
 protected:
   Operand(OperandKind Kind, Type Ty)
       : Ty(Ty), Kind(Kind), NumVars(0), Vars(nullptr) {}
@@ -123,7 +121,6 @@ protected:
     Vars = nullptr;
     NumVars = 0;
   }
-  ~Constant() override {}
   // PoolEntryID is an integer that uniquely identifies the constant
   // within its constant pool.  It is used for building the constant
   // pool in the object code and for referencing its entries.
@@ -163,7 +160,6 @@ public:
 private:
   ConstantPrimitive(Type Ty, PrimType Value, uint32_t PoolEntryID)
       : Constant(K, Ty, PoolEntryID), Value(Value) {}
-  ~ConstantPrimitive() override {}
   const PrimType Value;
 };
 
@@ -248,7 +244,6 @@ private:
                       bool SuppressMangling, uint32_t PoolEntryID)
       : Constant(kConstRelocatable, Ty, PoolEntryID), Offset(Offset),
         Name(Name), SuppressMangling(SuppressMangling) {}
-  ~ConstantRelocatable() override {}
   const RelocOffsetT Offset; // fixed offset to add
   const IceString Name;      // optional for debug/dump
   bool SuppressMangling;
@@ -285,7 +280,6 @@ public:
 private:
   ConstantUndef(Type Ty, uint32_t PoolEntryID)
       : Constant(kConstUndef, Ty, PoolEntryID) {}
-  ~ConstantUndef() override {}
 };
 
 // RegWeight is a wrapper for a uint32_t weight value, with a
@@ -494,7 +488,6 @@ protected:
     Vars[0] = this;
     NumVars = 1;
   }
-  ~Variable() override {}
   // Number is unique across all variables, and is used as a
   // (bit)vector index for liveness analysis.
   const SizeT Number;