diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -11082,11 +11082,11 @@
   bool MayNeedOverloadableChecks =
       AllowOverloadingOfFunction(Previous, S.Context, NewFD);
 
-  // Next, check ALL non-overloads to see if this is a redeclaration of a
-  // previous member of the MultiVersion set.
+  // Next, check ALL non-invalid non-overloads to see if this is a redeclaration
+  // of a previous member of the MultiVersion set.
   for (NamedDecl *ND : Previous) {
     FunctionDecl *CurFD = ND->getAsFunction();
-    if (!CurFD)
+    if (!CurFD || CurFD->isInvalidDecl())
       continue;
     if (MayNeedOverloadableChecks &&
         S.IsOverload(NewFD, CurFD, UseMemberUsingDeclRules))
diff --git a/clang/test/Sema/attr-target-mv.c b/clang/test/Sema/attr-target-mv.c
--- a/clang/test/Sema/attr-target-mv.c
+++ b/clang/test/Sema/attr-target-mv.c
@@ -52,6 +52,15 @@
 // expected-note@-2 {{previous definition is here}}
 int __attribute__((target("default"))) redef2(void) { return 1;}
 
+int redef3(void) { return 1; }
+// expected-warning@+4 {{attribute declaration must precede definition}}
+// expected-note@-2 {{previous definition is here}}
+// expected-error@+2 {{redefinition of 'redef3'}}
+// expected-note@-4 {{previous definition is here}}
+int __attribute__((target("default"))) redef3(void) { return 1; }
+// allow this, since we don't complain about more than one redefinition
+int __attribute__((target("sse4.2"))) redef3(void) { return 1; }
+
 int __attribute__((target("sse4.2"))) mv_after_use(void) { return 1; }
 int use3(void) {
   return mv_after_use();