diff --git a/llvm/lib/Target/AArch64/AArch64FastISel.cpp b/llvm/lib/Target/AArch64/AArch64FastISel.cpp
index cf344980cbaae..18e246e5af57d 100644
--- a/llvm/lib/Target/AArch64/AArch64FastISel.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FastISel.cpp
@@ -81,10 +81,7 @@ namespace {
 class AArch64FastISel final : public FastISel {
   class Address {
   public:
-    using BaseKind = enum {
-      RegBase,
-      FrameIndexBase
-    };
+    enum BaseKind { RegBase, FrameIndexBase };
 
   private:
     BaseKind Kind = RegBase;
diff --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
index 52cc4ca5a955c..1a14629fb66b3 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -435,7 +435,7 @@ void GCNHazardRecognizer::RecedeCycle() {
 // Helper Functions
 //===----------------------------------------------------------------------===//
 
-using HazardFnResult = enum { HazardFound, HazardExpired, NoHazardFound };
+enum HazardFnResult { HazardFound, HazardExpired, NoHazardFound };
 
 using IsExpiredFn = function_ref<bool(const MachineInstr &, int WaitStates)>;
 using GetNumWaitStatesFn = function_ref<unsigned int(const MachineInstr &)>;
diff --git a/llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp b/llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp
index 959ce6904ce4d..1682abbdea169 100644
--- a/llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp
@@ -43,7 +43,7 @@ class GCNNSAReassignImpl {
   bool run(MachineFunction &MF);
 
 private:
-  using NSA_Status = enum {
+  enum NSA_Status {
     NOT_NSA,        // Not an NSA instruction
     FIXED,          // NSA which we cannot modify
     NON_CONTIGUOUS, // NSA with non-sequential address which we can try
diff --git a/llvm/lib/Target/ARM/ARMFastISel.cpp b/llvm/lib/Target/ARM/ARMFastISel.cpp
index 14e1160e70dae..88d3b6f7d5bb9 100644
--- a/llvm/lib/Target/ARM/ARMFastISel.cpp
+++ b/llvm/lib/Target/ARM/ARMFastISel.cpp
@@ -86,7 +86,7 @@ namespace {
   // All possible address modes, plus some.
 class Address {
 public:
-  using BaseKind = enum { RegBase, FrameIndexBase };
+  enum BaseKind { RegBase, FrameIndexBase };
 
 private:
   BaseKind Kind = RegBase;
diff --git a/llvm/lib/Target/Mips/MipsFastISel.cpp b/llvm/lib/Target/Mips/MipsFastISel.cpp
index df0c8c13fa38d..06210b6b91b93 100644
--- a/llvm/lib/Target/Mips/MipsFastISel.cpp
+++ b/llvm/lib/Target/Mips/MipsFastISel.cpp
@@ -82,7 +82,7 @@ class MipsFastISel final : public FastISel {
   // All possible address modes.
   class Address {
   public:
-    using BaseKind = enum { RegBase, FrameIndexBase };
+    enum BaseKind { RegBase, FrameIndexBase };
 
   private:
     BaseKind Kind = RegBase;
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
index 2666342d0c7b9..66ed8b078b808 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
@@ -46,7 +46,7 @@ class WebAssemblyFastISel final : public FastISel {
   // All possible address modes.
   class Address {
   public:
-    using BaseKind = enum { RegBase, FrameIndexBase };
+    enum BaseKind { RegBase, FrameIndexBase };
 
   private:
     BaseKind Kind = RegBase;
diff --git a/llvm/lib/Target/X86/X86VZeroUpper.cpp b/llvm/lib/Target/X86/X86VZeroUpper.cpp
index f6f7e92d98578..2f28ab36aa193 100644
--- a/llvm/lib/Target/X86/X86VZeroUpper.cpp
+++ b/llvm/lib/Target/X86/X86VZeroUpper.cpp
@@ -66,7 +66,7 @@ namespace {
                           MachineBasicBlock &MBB);
     void addDirtySuccessor(MachineBasicBlock &MBB);
 
-    using BlockExitState = enum { PASS_THROUGH, EXITS_CLEAN, EXITS_DIRTY };
+    enum BlockExitState { PASS_THROUGH, EXITS_CLEAN, EXITS_DIRTY };
 
     static const char* getBlockExitStateName(BlockExitState ST);
 
diff --git a/llvm/unittests/ADT/FallibleIteratorTest.cpp b/llvm/unittests/ADT/FallibleIteratorTest.cpp
index d3389744ffbfe..c17aa0393dfcb 100644
--- a/llvm/unittests/ADT/FallibleIteratorTest.cpp
+++ b/llvm/unittests/ADT/FallibleIteratorTest.cpp
@@ -19,8 +19,8 @@ using namespace llvm;
 
 namespace {
 
-using ItemValid = enum { ValidItem, InvalidItem };
-using LinkValid = enum { ValidLink, InvalidLink };
+enum ItemValid { ValidItem, InvalidItem };
+enum LinkValid { ValidLink, InvalidLink };
 
 class Item {
 public: