4 files changed, 59 insertions, 1 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index b1c1d24..ab747a5 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -4171,6 +4171,18 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init,
       pre_init = true;
     }
 
+  bool zeroed_out = false;
+  if (!CONSTRUCTOR_NO_CLEARING (ctx->ctor))
+    {
+      /* We're initializing an array object that had been zero-initialized
+	 earlier.  Truncate ctx->ctor, and propagate its zeroed state by
+	 clearing CONSTRUCTOR_NO_CLEARING on each of the aggregate element
+	 initializers we append to it.  */
+      gcc_checking_assert (initializer_zerop (ctx->ctor));
+      zeroed_out = true;
+      vec_safe_truncate (*p, 0);
+    }
+
   tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p,
 					  overflow_p);
   unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts);
@@ -4182,7 +4194,11 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init,
       constexpr_ctx new_ctx;
       init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype);
       if (new_ctx.ctor != ctx->ctor)
-	CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor);
+	{
+	  if (zeroed_out)
+	    CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = false;
+	  CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor);
+	}
       if (TREE_CODE (elttype) == ARRAY_TYPE)
 	{
 	  /* A multidimensional array; recurse.  */
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-array26.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-array26.C
new file mode 100644
index 0000000..274f55a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-array26.C
@@ -0,0 +1,13 @@
+// PR c++/96282
+// { dg-do compile { target c++11 } }
+
+struct e { bool v = true; };
+
+template<int N>
+struct b { e m[N]; };
+
+template<int N>
+struct t : b<N> { constexpr t() : b<N>() {} };
+
+constexpr t<1> h1;
+constexpr t<42> h2;
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-array27.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-array27.C
new file mode 100644
index 0000000..1234cae
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-array27.C
@@ -0,0 +1,13 @@
+// PR c++/96282
+// { dg-do compile { target c++11 } }
+
+struct e { bool v = true; e *p = this; };
+
+template<int N>
+struct b { e m[N][N]; };
+
+template<int N>
+struct t : b<N> { constexpr t() : b<N>() {} };
+
+constexpr t<1> h1;
+constexpr t<42> h2;
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init18.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init18.C
new file mode 100644
index 0000000..47ad11f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init18.C
@@ -0,0 +1,16 @@
+// PR c++/96282
+// { dg-do compile { target c++20 } }
+
+struct e { bool v = true; bool w; };
+
+template<int N>
+struct b { e m[N][N]; };
+
+template<int N>
+struct t : b<N> { constexpr t() : b<N>() {} };
+
+constexpr t<1> h1;
+static_assert(h1.m[0][0].w == false);
+
+constexpr t<42> h2;
+static_assert(h2.m[17][17].w == false);