Index: lib/Format/FormatToken.h
===================================================================
--- lib/Format/FormatToken.h
+++ lib/Format/FormatToken.h
@@ -39,6 +39,7 @@
   TYPE(ConflictStart) \
   TYPE(CtorInitializerColon) \
   TYPE(CtorInitializerComma) \
+  TYPE(DesignatedInitializerLSquare) \
   TYPE(DesignatedInitializerPeriod) \
   TYPE(DictLiteral) \
   TYPE(ForEachMacro) \
Index: lib/Format/TokenAnnotator.cpp
===================================================================
--- lib/Format/TokenAnnotator.cpp
+++ lib/Format/TokenAnnotator.cpp
@@ -321,7 +321,7 @@
         Contexts.back().CanBeExpression && Left->isNot(TT_LambdaLSquare) &&
         CurrentToken->isNot(tok::l_brace) &&
         (!Parent ||
-         Parent->isOneOf(tok::colon, tok::l_square, tok::l_paren,
+         Parent->isOneOf(tok::colon, tok::l_square, tok::l_paren, tok::l_brace,
                          tok::kw_return, tok::kw_throw) ||
          Parent->isUnaryOperator() ||
          Parent->isOneOf(TT_ObjCForIn, TT_CastRParen) ||
@@ -336,6 +336,10 @@
                  Contexts.back().ContextKind == tok::l_brace &&
                  Parent->isOneOf(tok::l_brace, tok::comma)) {
         Left->Type = TT_JsComputedPropertyName;
+      } else if (Style.Language == FormatStyle::LK_Cpp &&
+                 Parent && Contexts.back().ContextKind == tok::l_brace &&
+                 Parent->isOneOf(tok::l_brace, tok::comma)) {
+        Left->Type = TT_DesignatedInitializerLSquare;
       } else if (CurrentToken->is(tok::r_square) && Parent &&
                  Parent->is(TT_TemplateCloser)) {
         Left->Type = TT_ArraySubscriptLSquare;
@@ -1954,7 +1958,8 @@
     if (Right.is(TT_LambdaLSquare) && Left.is(tok::equal))
       return 35;
     if (!Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
-                       TT_ArrayInitializerLSquare))
+                       TT_ArrayInitializerLSquare,
+                       TT_DesignatedInitializerLSquare))
       return 500;
   }
 
@@ -2368,8 +2373,9 @@
   if (Left.is(tok::greater) && Right.is(tok::greater))
     return Right.is(TT_TemplateCloser) && Left.is(TT_TemplateCloser) &&
            (Style.Standard != FormatStyle::LS_Cpp11 || Style.SpacesInAngles);
-  if (Right.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
-      Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar))
+  if (Right.isOneOf(tok::arrow, tok::arrowstar, tok::periodstar) ||
+      Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
+      (Right.is(tok::period) && Right.isNot(TT_DesignatedInitializerPeriod)))
     return false;
   if (!Style.SpaceBeforeAssignmentOperators &&
       Right.getPrecedence() == prec::Assignment)
Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -1521,6 +1521,16 @@
                "    .eeeeeeeeeeeeeeeeeeeeeeeeeee = 5};");
 
   verifyGoogleFormat("const struct A a = {.a = 1, .b = 2};");
+
+  verifyFormat("const struct A a = {[0] = 1, [1] = 2};");
+  verifyFormat("const struct A a = {[1] = aaaaaaaaaa, [2] = bbbbbbbbbb, [3] = cccccccccc,\n"
+			   "                    [4] = dddddddddd, [5] = eeeeeeeeee};");
+  verifyFormat("const struct Aaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaa = {\n"
+			   "    [1] = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "    [2] = bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb,\n"
+               "    [3] = cccccccccccccccccccccccccccccccccccccc,\n"
+               "    [4] = dddddddddddddddddddddddddddddddddddddd,\n"
+               "    [5] = eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee};");
 }
 
 TEST_F(FormatTest, NestedStaticInitializers) {
@@ -5593,6 +5603,8 @@
                "  T member = {arg1, arg2};\n"
                "};");
   verifyFormat("vector<int> foo = {::SomeGlobalFunction()};");
+  verifyFormat("const struct A a = {.a = 1, .b = 2};");
+  verifyFormat("const struct A a = {[0] = 1, [1] = 2};");
   verifyFormat("static_assert(std::is_integral<int>{} + 0, \"\");");
   verifyFormat("int a = std::is_integral<int>{} + 0;");
 
@@ -5758,6 +5770,8 @@
                "    aaaaaaa,\n"
                "    a};");
   verifyFormat("vector<int> foo = { ::SomeGlobalFunction() };", ExtraSpaces);
+  verifyFormat("const struct A a = { .a = 1, .b = 2 };", ExtraSpaces);
+  verifyFormat("const struct A a = { [0] = 1, [1] = 2 };", ExtraSpaces);
 }
 
 TEST_F(FormatTest, FormatsBracedListsInColumnLayout) {