Index: lib/CodeGen/CGExprConstant.cpp
===================================================================
--- lib/CodeGen/CGExprConstant.cpp
+++ lib/CodeGen/CGExprConstant.cpp
@@ -2119,6 +2119,16 @@
       Elts.push_back(C);
     }
 
+    /* This means that the array type is probably "IncompleteType" or some
+       type that is not ConstantArray.  */
+    if (CAT == nullptr && CommonElementType == nullptr && !NumInitElts) {
+      const ArrayType *AT = CGM.getContext().getAsArrayType(DestType);
+      CommonElementType = CGM.getTypes().ConvertType(AT->getElementType());
+      llvm::ArrayType *AType = llvm::ArrayType::get(CommonElementType,
+                                                    NumElements);
+      return llvm::ConstantAggregateZero::get(AType);
+    }
+
     return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts,
                              Filler);
   }
Index: test/CodeGenCXX/empty-struct-init-list.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/empty-struct-init-list.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -std=c++11 -emit-llvm %s
+// RUN: %clang_cc1 -std=c++14 -emit-llvm %s
+// RUN: %clang_cc1 -std=c++17 -emit-llvm %s
+// expected-no-diagnostics
+
+typedef struct { } a;
+
+typedef struct {
+  a b[];
+} c;
+c d{ };