[TableGen] Do not compile CombineRuleBuilder::verify in release builds

[Pierre-vh]

Summary

Avoids a warning about the function being unused.

[DavidSpickett]

Nice, thanks!

llvm/utils/TableGen/GlobalISelCombinerMatchTableEmitter.cpp

public:
   /// Emits all RuleMatchers into the vector of RuleMatchers passed in the
   /// constructor.
   bool emitRuleMatchers();
 
   void print(raw_ostream &OS) const;
   void dump() const { print(dbgs()); }
 
   /// Debug-only verification of invariants.
+#ifndef NDEBUG
   void verify() const;
+#endif
 
 private:
   void PrintError(Twine Msg) const { ::PrintError(RuleDef.getLoc(), Msg); }
 
   /// Adds the expansions from \see MatchDatas to \p CE.
   void declareAllMatchDatasExpansions(CodeExpansions &CE) const;
 
   /// Adds \p P to \p IM, expanding its code using \p CE.
for (const auto &[Key, Val] : OperandTable) {
       OS << "]\n";
     }
     OS << "  )\n";
   }
 
   OS << ")\n";
 }
 
+#ifndef NDEBUG
 void CombineRuleBuilder::verify() const {
   const auto VerifyPats = [&](const PatternMap &Pats) {
     for (const auto &[Name, Pat] : Pats) {
       if (!Pat)
         PrintFatalError("null pattern in pattern map!");
 
       if (Name != Pat->getName()) {
         Pat->dump();
void CombineRuleBuilder::verify() const {
   for (const auto &[Name, Op] : OperandTable) {
     if (Op.ApplyPat && !Op.MatchPat) {
       dump();
       PrintFatalError("Operand " + Name +
                       " has an apply pattern, but no match pattern!");
     }
   }
 }
+#endif
 
 bool CombineRuleBuilder::addFeaturePredicates(RuleMatcher &M) {
   if (!RuleDef.getValue("Predicates"))
     return true;
 
   ListInit *Preds = RuleDef.getValueAsListInit("Predicates");
   for (Init *I : Preds->getValues()) {
     if (DefInit *Pred = dyn_cast<DefInit>(I)) {