Index: clang/lib/Basic/ParsedAttrInfo.cpp
===================================================================
--- clang/lib/Basic/ParsedAttrInfo.cpp
+++ clang/lib/Basic/ParsedAttrInfo.cpp
@@ -25,7 +25,7 @@
   static llvm::ManagedStatic<std::list<std::unique_ptr<ParsedAttrInfo>>>
       PluginAttrInstances;
   if (PluginAttrInstances->empty())
-    for (auto It : ParsedAttrInfoRegistry::entries())
+    for (const auto &It : ParsedAttrInfoRegistry::entries())
       PluginAttrInstances->emplace_back(It.instantiate());
 
   return *PluginAttrInstances;
Index: clang/lib/CodeGen/TargetInfo.cpp
===================================================================
--- clang/lib/CodeGen/TargetInfo.cpp
+++ clang/lib/CodeGen/TargetInfo.cpp
@@ -7916,7 +7916,7 @@
     if (isVectorTypeBased(FT->getReturnType().getTypePtr(), /*IsParam*/true))
       return true;
   if (const FunctionProtoType *Proto = Ty->getAs<FunctionProtoType>())
-    for (auto ParamType : Proto->getParamTypes())
+    for (const auto &ParamType : Proto->getParamTypes())
       if (isVectorTypeBased(ParamType.getTypePtr(), /*IsParam*/true))
         return true;
 
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -865,7 +865,7 @@
   S.getUndefinedButUsed(Undefined);
   if (Undefined.empty()) return;
 
-  for (auto Undef : Undefined) {
+  for (const auto &Undef : Undefined) {
     ValueDecl *VD = cast<ValueDecl>(Undef.first);
     SourceLocation UseLoc = Undef.second;
 
Index: clang/lib/Sema/SemaRISCVVectorLookup.cpp
===================================================================
--- clang/lib/Sema/SemaRISCVVectorLookup.cpp
+++ clang/lib/Sema/SemaRISCVVectorLookup.cpp
@@ -253,7 +253,7 @@
 
         // Create non-masked policy intrinsic.
         if (Record.UnMaskedPolicyScheme != PolicyScheme::SchemeNone) {
-          for (auto P : SupportedUnMaskedPolicies) {
+          for (const auto &P : SupportedUnMaskedPolicies) {
             llvm::SmallVector<PrototypeDescriptor> PolicyPrototype =
                 RVVIntrinsic::computeBuiltinTypes(
                     BasicProtoSeq, /*IsMasked=*/false,
Index: clang/lib/Sema/SemaStmtAttr.cpp
===================================================================
--- clang/lib/Sema/SemaStmtAttr.cpp
+++ clang/lib/Sema/SemaStmtAttr.cpp
@@ -238,7 +238,7 @@
            << A;
   }
 
-  for (auto Tup :
+  for (const auto &Tup :
        llvm::zip_longest(OrigCEF.getCallExprs(), CEF.getCallExprs())) {
     // If the original call expression already had a callee, we already
     // diagnosed this, so skip it here. We can't skip if there isn't a 1:1