diff --git a/llvm/utils/TableGen/AsmMatcherEmitter.cpp b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
--- a/llvm/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
@@ -3347,7 +3347,7 @@
       return true;
     if (A.size() > B.size())
       return false;
-    for (const auto &Pair : zip(A, B)) {
+    for (auto Pair : zip(A, B)) {
       if (std::get<0>(Pair)->getName() < std::get<1>(Pair)->getName())
         return true;
       if (std::get<0>(Pair)->getName() > std::get<1>(Pair)->getName())
diff --git a/llvm/utils/TableGen/CodeEmitterGen.cpp b/llvm/utils/TableGen/CodeEmitterGen.cpp
--- a/llvm/utils/TableGen/CodeEmitterGen.cpp
+++ b/llvm/utils/TableGen/CodeEmitterGen.cpp
@@ -563,7 +563,7 @@
       return true;
     if (A.size() > B.size())
       return false;
-    for (const auto &Pair : zip(A, B)) {
+    for (auto Pair : zip(A, B)) {
       if (std::get<0>(Pair)->getName() < std::get<1>(Pair)->getName())
         return true;
       if (std::get<0>(Pair)->getName() > std::get<1>(Pair)->getName())
diff --git a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -636,7 +636,7 @@
   /// Return true if S has no element (vector type) that T is a sub-vector of,
   /// i.e. has the same element type as T and more elements.
   auto NoSubV = [&IsSubVec](const TypeSetByHwMode::SetType &S, MVT T) -> bool {
-    for (const auto &I : S)
+    for (auto I : S)
       if (IsSubVec(T, I))
         return false;
     return true;
@@ -645,7 +645,7 @@
   /// Return true if S has no element (vector type) that T is a super-vector
   /// of, i.e. has the same element type as T and fewer elements.
   auto NoSupV = [&IsSubVec](const TypeSetByHwMode::SetType &S, MVT T) -> bool {
-    for (const auto &I : S)
+    for (auto I : S)
       if (IsSubVec(I, T))
         return false;
     return true;
diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -1181,7 +1181,7 @@
     TypeIDValues.clear();
 
     unsigned ID = 0;
-    for (const LLTCodeGen LLTy : KnownTypes)
+    for (const LLTCodeGen &LLTy : KnownTypes)
       TypeIDValues[LLTy] = ID++;
   }
 
@@ -2153,7 +2153,7 @@
         return false;
     }
 
-    for (const auto &Operand : zip(Operands, B.Operands)) {
+    for (auto Operand : zip(Operands, B.Operands)) {
       if (std::get<0>(Operand)->isHigherPriorityThan(*std::get<1>(Operand)))
         return true;
       if (std::get<1>(Operand)->isHigherPriorityThan(*std::get<0>(Operand)))
@@ -3159,7 +3159,7 @@
   if (Matchers.size() < B.Matchers.size())
     return false;
 
-  for (const auto &Matcher : zip(Matchers, B.Matchers)) {
+  for (auto Matcher : zip(Matchers, B.Matchers)) {
     if (std::get<0>(Matcher)->isHigherPriorityThan(*std::get<1>(Matcher)))
       return true;
     if (std::get<1>(Matcher)->isHigherPriorityThan(*std::get<0>(Matcher)))
@@ -5176,7 +5176,7 @@
       return true;
     if (A.size() > B.size())
       return false;
-    for (const auto &Pair : zip(A, B)) {
+    for (auto Pair : zip(A, B)) {
       if (std::get<0>(Pair)->getName() < std::get<1>(Pair)->getName())
         return true;
       if (std::get<0>(Pair)->getName() > std::get<1>(Pair)->getName())
diff --git a/llvm/utils/TableGen/OptParserEmitter.cpp b/llvm/utils/TableGen/OptParserEmitter.cpp
--- a/llvm/utils/TableGen/OptParserEmitter.cpp
+++ b/llvm/utils/TableGen/OptParserEmitter.cpp
@@ -241,9 +241,9 @@
     OS << "bool ValuesWereAdded;\n";
     OS << R.getValueAsString("ValuesCode");
     OS << "\n";
-    for (const std::string &Pref : R.getValueAsListOfStrings("Prefixes")) {
+    for (std::string S : R.getValueAsListOfStrings("Prefixes")) {
       OS << "ValuesWereAdded = Opt.addValues(";
-      std::string S = (Pref + R.getValueAsString("Name")).str();
+      S += R.getValueAsString("Name");
       write_cstring(OS, S);
       OS << ", Values);\n";
       OS << "(void)ValuesWereAdded;\n";