Index: include/llvm/TableGen/Record.h
===================================================================
--- include/llvm/TableGen/Record.h
+++ include/llvm/TableGen/Record.h
@@ -1491,7 +1491,7 @@
   /// its value as a string, throwing an exception if the field does not exist
   /// or if the value is not a string.
   ///
-  std::string getValueAsString(StringRef FieldName) const;
+  StringRef getValueAsString(StringRef FieldName) const;
 
   /// This method looks up the specified field and returns
   /// its value as a BitsInit, throwing an exception if the field does not exist
@@ -1521,7 +1521,7 @@
   /// returns its value as a vector of strings, throwing an exception if the
   /// field does not exist or if the value is not the right type.
   ///
-  std::vector<std::string> getValueAsListOfStrings(StringRef FieldName) const;
+  std::vector<StringRef> getValueAsListOfStrings(StringRef FieldName) const;
 
   /// This method looks up the specified field and returns its
   /// value as a Record, throwing an exception if the field does not exist or if
Index: lib/TableGen/Record.cpp
===================================================================
--- lib/TableGen/Record.cpp
+++ lib/TableGen/Record.cpp
@@ -1708,7 +1708,7 @@
   return R->getValue();
 }
 
-std::string Record::getValueAsString(StringRef FieldName) const {
+StringRef Record::getValueAsString(StringRef FieldName) const {
   const RecordVal *R = getValue(FieldName);
   if (!R || !R->getValue())
     PrintFatalError(getLoc(), "Record `" + getName() +
@@ -1787,10 +1787,10 @@
   return Ints;
 }
 
-std::vector<std::string>
+std::vector<StringRef>
 Record::getValueAsListOfStrings(StringRef FieldName) const {
   ListInit *List = getValueAsListInit(FieldName);
-  std::vector<std::string> Strings;
+  std::vector<StringRef> Strings;
   for (Init *I : List->getValues()) {
     if (StringInit *SI = dyn_cast<StringInit>(I))
       Strings.push_back(SI->getValue());
Index: utils/TableGen/AsmMatcherEmitter.cpp
===================================================================
--- utils/TableGen/AsmMatcherEmitter.cpp
+++ utils/TableGen/AsmMatcherEmitter.cpp
@@ -2486,14 +2486,18 @@
       if (!MatchCode.empty())
         MatchCode += "else ";
       MatchCode += "if ((Features & " + FeatureMask + ") == "+FeatureMask+")\n";
-      MatchCode += "  Mnemonic = \"" +R->getValueAsString("ToMnemonic")+"\";\n";
+      MatchCode += "  Mnemonic = \"";
+      MatchCode += R->getValueAsString("ToMnemonic");
+      MatchCode += "\";\n";
     }
 
     if (AliasWithNoPredicate != -1) {
       Record *R = ToVec[AliasWithNoPredicate];
       if (!MatchCode.empty())
         MatchCode += "else\n  ";
-      MatchCode += "Mnemonic = \"" + R->getValueAsString("ToMnemonic")+"\";\n";
+      MatchCode += "Mnemonic = \"";
+      MatchCode += R->getValueAsString("ToMnemonic");
+      MatchCode += "\";\n";
     }
 
     MatchCode += "return;";
Index: utils/TableGen/AsmWriterEmitter.cpp
===================================================================
--- utils/TableGen/AsmWriterEmitter.cpp
+++ utils/TableGen/AsmWriterEmitter.cpp
@@ -523,7 +523,7 @@
       // If the register has an alternate name for this index, use it.
       // Otherwise, leave it empty as an error flag.
       if (Idx < e) {
-        std::vector<std::string> AltNames =
+        std::vector<StringRef> AltNames =
           Reg.TheDef->getValueAsListOfStrings("AltNames");
         if (AltNames.size() <= Idx)
           PrintFatalError(Reg.TheDef->getLoc(),
Index: utils/TableGen/CodeEmitterGen.cpp
===================================================================
--- utils/TableGen/CodeEmitterGen.cpp
+++ utils/TableGen/CodeEmitterGen.cpp
@@ -278,11 +278,11 @@
     if (R->getValueAsString("Namespace") == "TargetOpcode" ||
         R->getValueAsBit("isPseudo"))
       continue;
-    const std::string &InstName = R->getValueAsString("Namespace") + "::"
-      + R->getName().str();
+    std::string InstName =
+        (R->getValueAsString("Namespace") + "::" + R->getName()).str();
     std::string Case = getInstructionCase(R, Target);
 
-    CaseMap[Case].push_back(InstName);
+    CaseMap[Case].push_back(std::move(InstName));
   }
 
   // Emit initial function code
Index: utils/TableGen/CodeGenDAGPatterns.cpp
===================================================================
--- utils/TableGen/CodeGenDAGPatterns.cpp
+++ utils/TableGen/CodeGenDAGPatterns.cpp
@@ -893,7 +893,9 @@
   for (Record *Pred : PredicateRecs) {
     if (!PredicateCheck.empty())
       PredicateCheck += " && ";
-    PredicateCheck += "(" + Pred->getValueAsString("CondString") + ")";
+    PredicateCheck += "(";
+    PredicateCheck += Pred->getValueAsString("CondString");
+    PredicateCheck += ")";
   }
 
   return PredicateCheck.str();
Index: utils/TableGen/GlobalISelEmitter.cpp
===================================================================
--- utils/TableGen/GlobalISelEmitter.cpp
+++ utils/TableGen/GlobalISelEmitter.cpp
@@ -118,7 +118,7 @@
 
 std::string explainOperator(Record *Operator) {
   if (Operator->isSubClassOf("SDNode"))
-    return " (" + Operator->getValueAsString("Opcode") + ")";
+    return (" (" + Operator->getValueAsString("Opcode") + ")").str();
 
   if (Operator->isSubClassOf("Intrinsic"))
     return (" (Operator is an Intrinsic, " + Operator->getName() + ")").str();
Index: utils/TableGen/OptParserEmitter.cpp
===================================================================
--- utils/TableGen/OptParserEmitter.cpp
+++ utils/TableGen/OptParserEmitter.cpp
@@ -53,22 +53,22 @@
 
   // Compare options by name, unless they are sentinels.
   if (!ASent)
-    if (int Cmp = StrCmpOptionName(A->getValueAsString("Name").c_str(),
-                                   B->getValueAsString("Name").c_str()))
+    if (int Cmp = StrCmpOptionName(A->getValueAsString("Name").str().c_str(),
+                                   B->getValueAsString("Name").str().c_str()))
       return Cmp;
 
   if (!ASent) {
-    std::vector<std::string> APrefixes = A->getValueAsListOfStrings("Prefixes");
-    std::vector<std::string> BPrefixes = B->getValueAsListOfStrings("Prefixes");
-
-    for (std::vector<std::string>::const_iterator APre = APrefixes.begin(),
-                                                  AEPre = APrefixes.end(),
-                                                  BPre = BPrefixes.begin(),
-                                                  BEPre = BPrefixes.end();
-                                                  APre != AEPre &&
-                                                  BPre != BEPre;
-                                                  ++APre, ++BPre) {
-      if (int Cmp = StrCmpOptionName(APre->c_str(), BPre->c_str()))
+    std::vector<StringRef> APrefixes = A->getValueAsListOfStrings("Prefixes");
+    std::vector<StringRef> BPrefixes = B->getValueAsListOfStrings("Prefixes");
+
+    for (std::vector<StringRef>::const_iterator APre = APrefixes.begin(),
+                                                AEPre = APrefixes.end(),
+                                                BPre = BPrefixes.begin(),
+                                                BEPre = BPrefixes.end();
+                                                APre != AEPre &&
+                                                BPre != BEPre;
+                                                ++APre, ++BPre) {
+      if (int Cmp = StrCmpOptionName(APre->str().c_str(), BPre->str().c_str()))
         return Cmp;
     }
   }
@@ -122,7 +122,7 @@
   unsigned CurPrefix = 0;
   for (unsigned i = 0, e = Opts.size(); i != e; ++i) {
     const Record &R = *Opts[i];
-    std::vector<std::string> prf = R.getValueAsListOfStrings("Prefixes");
+    std::vector<StringRef> prf = R.getValueAsListOfStrings("Prefixes");
     PrefixKeyT prfkey(prf.begin(), prf.end());
     unsigned NewPrefix = CurPrefix + 1;
     if (Prefixes.insert(std::make_pair(prfkey, (Twine("prefix_") +
@@ -207,7 +207,7 @@
     OS << "OPTION(";
 
     // The option prefix;
-    std::vector<std::string> prf = R.getValueAsListOfStrings("Prefixes");
+    std::vector<StringRef> prf = R.getValueAsListOfStrings("Prefixes");
     OS << Prefixes[PrefixKeyT(prf.begin(), prf.end())] << ", ";
 
     // The option string.
@@ -240,7 +240,7 @@
     // would become "foo\0bar\0". Note that the compiler adds an implicit
     // terminating \0 at the end.
     OS << ", ";
-    std::vector<std::string> AliasArgs = R.getValueAsListOfStrings("AliasArgs");
+    std::vector<StringRef> AliasArgs = R.getValueAsListOfStrings("AliasArgs");
     if (AliasArgs.size() == 0) {
       OS << "nullptr";
     } else {