Index: clang/lib/AST/Interp/ByteCodeStmtGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeStmtGen.cpp
+++ clang/lib/AST/Interp/ByteCodeStmtGen.cpp
@@ -394,10 +394,9 @@
     return true;
   }
 
+  const Expr *Init = VD->getInit();
   // Integers, pointers, primitives.
   if (Optional<PrimType> T = this->classify(VD->getType())) {
-    const Expr *Init = VD->getInit();
-
     unsigned Offset =
         this->allocateLocalPrimitive(VD, *T, VD->getType().isConstQualified());
     // Compile the initializer in its own scope.
@@ -412,8 +411,11 @@
   }
 
   // Composite types - allocate storage and initialize it.
-  if (Optional<unsigned> Offset = this->allocateLocal(VD))
-    return this->visitLocalInitializer(VD->getInit(), *Offset);
+  if (Optional<unsigned> Offset = this->allocateLocal(VD)) {
+    if (Init)
+      return this->visitLocalInitializer(Init, *Offset);
+    return true;
+  }
 
   return this->bail(VD);
 }
Index: clang/test/AST/Interp/cxx20.cpp
===================================================================
--- clang/test/AST/Interp/cxx20.cpp
+++ clang/test/AST/Interp/cxx20.cpp
@@ -70,6 +70,11 @@
 }
 static_assert(initializedLocal() == 20);
 
+constexpr void uninitializedLocalArray() {
+  int a[]; // expected-error {{needs an explicit size or an initializer}} \
+           // ref-error {{needs an explicit size or an initializer}}
+}
+
 #if 0
 // FIXME: This code should be rejected because we pass an uninitialized value
 //   as a function parameter.