diff --git a/clang/lib/CodeGen/Targets/AArch64.cpp b/clang/lib/CodeGen/Targets/AArch64.cpp
index 725e8a70fddfe..85117366de0ee 100644
--- a/clang/lib/CodeGen/Targets/AArch64.cpp
+++ b/clang/lib/CodeGen/Targets/AArch64.cpp
@@ -886,9 +886,11 @@ void AArch64ABIInfo::appendAttributeMangling(StringRef AttrStr,
     return LHS.compare(RHS) < 0;
   });
 
+  llvm::SmallDenseSet<StringRef, 8> UniqueFeats;
   for (auto &Feat : Features)
     if (auto Ext = llvm::AArch64::parseArchExtension(Feat))
-      Out << 'M' << Ext->Name;
+      if (UniqueFeats.insert(Ext->Name).second)
+        Out << 'M' << Ext->Name;
 }
 
 std::unique_ptr<TargetCodeGenInfo>
diff --git a/clang/test/CodeGen/attr-target-version.c b/clang/test/CodeGen/attr-target-version.c
index ae1a8772f6cc0..b7112c783da91 100644
--- a/clang/test/CodeGen/attr-target-version.c
+++ b/clang/test/CodeGen/attr-target-version.c
@@ -273,7 +273,7 @@ int hoo(void) {
 // CHECK-NEXT:    [[TMP3:%.*]] = and i1 true, [[TMP2]]
 // CHECK-NEXT:    br i1 [[TMP3]], label [[RESOLVER_RETURN:%.*]], label [[RESOLVER_ELSE:%.*]]
 // CHECK:       resolver_return:
-// CHECK-NEXT:    ret ptr @fmv_inline._MfcmaMfp16Mfp16MrdmMsme
+// CHECK-NEXT:    ret ptr @fmv_inline._MfcmaMfp16MrdmMsme
 // CHECK:       resolver_else:
 // CHECK-NEXT:    [[TMP4:%.*]] = load i64, ptr @__aarch64_cpu_features, align 8
 // CHECK-NEXT:    [[TMP5:%.*]] = and i64 [[TMP4]], 864726312827224064
@@ -582,7 +582,7 @@ int hoo(void) {
 //
 //
 // CHECK: Function Attrs: noinline nounwind optnone
-// CHECK-LABEL: define {{[^@]+}}@fmv_inline._MfcmaMfp16Mfp16MrdmMsme
+// CHECK-LABEL: define {{[^@]+}}@fmv_inline._MfcmaMfp16MrdmMsme
 // CHECK-SAME: () #[[ATTR13:[0-9]+]] {
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    ret i32 2