1 files changed, 107 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/init/array56.C b/gcc/testsuite/g++.dg/init/array56.C
new file mode 100644
index 00000000000..63e16663ec1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/array56.C
@@ -0,0 +1,107 @@
+/* PR c++/90938 - Initializing array with {1} works, but not {0}
+   { dg-do compile { target c++11 } }
+   { dg-options "-O -Wall -fdump-tree-optimized" } */
+
+#define assert(e)						\
+  ((e) ? (void)0						\
+   : (__builtin_printf ("assertion failed on line %i: %s\n",	\
+			__LINE__, #e),				\
+      __builtin_abort ()))
+
+namespace A {
+
+struct X
+{
+  X () = default;
+  X (int n) : n (n + 1) { }
+  int n;
+};
+
+static_assert (__is_trivial (X), "X is trivial");
+
+static void test ()
+{
+  {
+    X x[] { 0 };
+    assert (1 == x->n);
+  }
+
+  {
+    X x[1] { 0 };
+    assert (1 == x->n);                     // fails
+  }
+
+  {
+    X x[2] { 0 };
+    assert (1 == x[0].n && 0 == x[1].n);    // fails
+  }
+
+  {
+    X x[] { 1, 0 };
+    assert (2 == x[0].n && 1 == x[1].n);    // passes
+  }
+
+  {
+    X x[2] { 1, 0 };
+    assert (2 == x[0].n && 1 == x[1].n);    // fails
+  }
+}
+
+}
+
+namespace B {
+
+struct X
+{
+  X () = default;
+  X (int *p) : p (p ? p : new int (1)) { }
+  int *p;
+};
+
+static_assert (__is_trivial (X), "X is trivial");
+
+static void test ()
+{
+  X x[1] { nullptr };
+  assert (*x->p == 1);   // fails
+
+  X y[1] { 0 };
+  assert (*y->p == 1);   // fails
+}
+
+}
+
+namespace C {
+
+static const char *vector_swizzle (int vecsize, int index)
+{
+  static const char *swizzle[4][4] =
+    {
+     { ".x", ".y", ".z", ".w" },
+     { ".xy", ".yz", ".zw", nullptr },
+     { ".xyz", ".yzw", nullptr, nullptr },
+     { "", nullptr, nullptr, nullptr },
+    };
+
+  assert (vecsize >= 1 && vecsize <= 4);
+  assert (index >= 0 && index < 4);
+  assert (swizzle[vecsize - 1][index]);
+
+  return swizzle[vecsize - 1][index];
+}
+
+static void test ()
+{
+  assert (!*vector_swizzle(4, 0));
+}
+
+}
+
+int main ()
+{
+  A::test ();
+  B::test ();
+  C::test ();
+}
+
+// { dg-final { scan-tree-dump-not "abort" "optimized" } }