diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
index 2dcd7805b6c96..dbb658940eef1 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
@@ -61,7 +61,7 @@ class DWARFFormValue {
   const DWARFUnit *U = nullptr; /// Remember the DWARFUnit at extract time.
   const DWARFContext *C = nullptr; /// Context for extract time.
 
-  DWARFFormValue(dwarf::Form F, ValueType V) : Form(F), Value(V) {}
+  DWARFFormValue(dwarf::Form F, const ValueType &V) : Form(F), Value(V) {}
 
 public:
   DWARFFormValue(dwarf::Form F = dwarf::Form(0)) : Form(F) {}
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
index e54ec4f2b1d72..bff49dab4a313 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
@@ -198,7 +198,7 @@ struct TargetRegionEntryInfo {
                                          unsigned DeviceID, unsigned FileID,
                                          unsigned Line, unsigned Count);
 
-  bool operator<(const TargetRegionEntryInfo RHS) const {
+  bool operator<(const TargetRegionEntryInfo &RHS) const {
     return std::make_tuple(ParentName, DeviceID, FileID, Line, Count) <
            std::make_tuple(RHS.ParentName, RHS.DeviceID, RHS.FileID, RHS.Line,
                            RHS.Count);
diff --git a/llvm/lib/CodeGen/RegAllocGreedy.h b/llvm/lib/CodeGen/RegAllocGreedy.h
index 1941643bba9e6..06cf0828ea79b 100644
--- a/llvm/lib/CodeGen/RegAllocGreedy.h
+++ b/llvm/lib/CodeGen/RegAllocGreedy.h
@@ -425,7 +425,7 @@ class LLVM_LIBRARY_VISIBILITY RAGreedy : public MachineFunctionPass,
                ZeroCostFoldedReloads || Copies);
     }
 
-    void add(RAGreedyStats other) {
+    void add(const RAGreedyStats &other) {
       Reloads += other.Reloads;
       FoldedReloads += other.FoldedReloads;
       ZeroCostFoldedReloads += other.ZeroCostFoldedReloads;
diff --git a/llvm/lib/ObjCopy/ELF/ELFObject.h b/llvm/lib/ObjCopy/ELF/ELFObject.h
index f72c109b6009e..2b1895a30b41e 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObject.h
+++ b/llvm/lib/ObjCopy/ELF/ELFObject.h
@@ -910,7 +910,7 @@ class RelocationSection
 
 public:
   RelocationSection(const Object &O) : Obj(O) {}
-  void addRelocation(Relocation Rel) { Relocations.push_back(Rel); }
+  void addRelocation(const Relocation &Rel) { Relocations.push_back(Rel); }
   Error accept(SectionVisitor &Visitor) const override;
   Error accept(MutableSectionVisitor &Visitor) override;
   Error removeSectionReferences(