Index: lib/Format/ContinuationIndenter.cpp
===================================================================
--- lib/Format/ContinuationIndenter.cpp
+++ lib/Format/ContinuationIndenter.cpp
@@ -1000,8 +1000,7 @@
                        Current.MatchingParen->Previous &&
                        Current.MatchingParen->Previous->is(tok::comma);
     AvoidBinPacking =
-        (Current.is(TT_ArrayInitializerLSquare) && EndsInComma) ||
-        Current.is(TT_DictLiteral) ||
+        EndsInComma || Current.is(TT_DictLiteral) ||
         Style.Language == FormatStyle::LK_Proto || !Style.BinPackArguments ||
         (NextNoComment && NextNoComment->is(TT_DesignatedInitializerPeriod));
     if (Current.ParameterCount > 1)
Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -5617,6 +5617,17 @@
                "};");
   verifyFormat("#define A {a, a},");
 
+  // Binpacking only if there is no trailing comma
+  verifyFormat("const Aaaaaa aaaaa = {aaaaaaaaaa, bbbbbbbbbb,\n"
+               "                      cccccccccc, dddddddddd};",
+			   getLLVMStyleWithColumns(50));
+  verifyFormat("const Aaaaaa aaaaa = {\n"
+               "    aaaaaaaaaaa,\n"
+               "    bbbbbbbbbbb,\n"
+               "    ccccccccccc,\n"
+               "    ddddddddddd,\n"
+               "};", getLLVMStyleWithColumns(50));
+
   // Cases where distinguising braced lists and blocks is hard.
   verifyFormat("vector<int> v{12} GUARDED_BY(mutex);");
   verifyFormat("void f() {\n"
@@ -5696,10 +5707,12 @@
                    "                           // Second element:\n"
                    "                           2};",
                    getLLVMStyleWithColumns(30)));
-  // A trailing comma should still lead to an enforced line break.
+  // A trailing comma should still lead to an enforced line break and no
+  // binpacking.
   EXPECT_EQ("vector<int> SomeVector = {\n"
             "    // aaa\n"
-            "    1, 2,\n"
+            "    1,\n"
+            "    2,\n"
             "};",
             format("vector<int> SomeVector = { // aaa\n"
                    "    1, 2, };"));
@@ -5784,7 +5797,7 @@
                "    X86::RAX, X86::RDX, X86::RCX, X86::RSI, X86::RDI,\n"
                "    X86::R8,  X86::R9,  X86::R10, X86::R11, 0};");
   verifyFormat("static const uint16_t CallerSavedRegs64Bittttt[] = {\n"
-               "    X86::RAX, X86::RDX, X86::RCX, X86::RSI, X86::RDI,\n"
+			   "    X86::RAX, X86::RDX, X86::RCX, X86::RSI, X86::RDI,\n"
                "    // Separating comment.\n"
                "    X86::R8, X86::R9, X86::R10, X86::R11, 0};");
   verifyFormat("static const uint16_t CallerSavedRegs64Bittttt[] = {\n"
@@ -5863,8 +5876,8 @@
       "     aaaaaaaaaaaa, a, aaaaaaaaaa, aaaaaaaaa, aaa}};");
 
   // No column layout should be used here.
-  verifyFormat("aaaaaaaaaaaaaaa = {aaaaaaaaaaaaaaaaaaaaaaaaaaa, 0, 0,\n"
-               "                   bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb};");
+  verifyFormat("aaaaaaaaaaaaaaa = {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, 0, 0,\n"
+			   "                   bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb};");
 
   verifyNoCrash("a<,");