diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index fe6295f3069cf0..d1f407259cb6e3 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -1438,7 +1438,7 @@ def Final : InheritableAttr {
 def MinSize : InheritableAttr {
   let Spellings = [Clang<"minsize">];
   let Subjects = SubjectList<[Function, ObjCMethod], ErrorDiag>;
-  let Documentation = [Undocumented];
+  let Documentation = [MinSizeDocs];
 }
 
 def FlagEnum : InheritableAttr {
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 872eb8a266734e..59bbc80708ed56 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -5833,6 +5833,15 @@ attribute can also be written using C++11 syntax: ``[[mig::server_routine]]``.
 }];
 }
 
+def MinSizeDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+This function attribute indicates that optimization passes and code generator passes
+make choices that keep the function code size as small as possible. Optimizations may
+also sacrifice runtime performance in order to minimize the size of the generated code.
+  }];
+}
+
 def MSAllocatorDocs : Documentation {
   let Category = DocCatFunction;
   let Content = [{