diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 33a1ca24c9f..5d909ef62ec 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2019-02-18  Jason Merrill  <jason@redhat.com>
 
+	PR c++/89336 - multiple stores in constexpr stmt.
+	* constexpr.c (cxx_eval_store_expression): Preevaluate scalar or
+	assigned value.
+
 	* pt.c (check_explicit_specialization): If the declarator is a
 	template-id, only check whether the arguments are dependent.
 
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index d946a797999..d413c6b9b27 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -3634,6 +3634,18 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,
   maybe_simplify_trivial_copy (target, init);
 
   tree type = TREE_TYPE (target);
+  bool preeval = SCALAR_TYPE_P (type) || TREE_CODE (t) == MODIFY_EXPR;
+  if (preeval)
+    {
+      /* Evaluate the value to be stored without knowing what object it will be
+	 stored in, so that any side-effects happen first.  */
+      if (!SCALAR_TYPE_P (type))
+	new_ctx.ctor = new_ctx.object = NULL_TREE;
+      init = cxx_eval_constant_expression (&new_ctx, init, false,
+					   non_constant_p, overflow_p);
+      if (*non_constant_p)
+	return t;
+    }
   target = cxx_eval_constant_expression (ctx, target,
 					 true,
 					 non_constant_p, overflow_p);
@@ -3834,7 +3846,7 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,
     }
   release_tree_vector (refs);
 
-  if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type))
+  if (!preeval)
     {
       /* Create a new CONSTRUCTOR in case evaluation of the initializer
 	 wants to modify it.  */
@@ -3843,21 +3855,20 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,
 	  *valp = build_constructor (type, NULL);
 	  CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init;
 	}
-      else if (TREE_CODE (*valp) == PTRMEM_CST)
-	*valp = cplus_expand_constant (*valp);
       new_ctx.ctor = *valp;
       new_ctx.object = target;
+      init = cxx_eval_constant_expression (&new_ctx, init, false,
+					   non_constant_p, overflow_p);
+      if (target == object)
+	/* The hash table might have moved since the get earlier.  */
+	valp = ctx->values->get (object);
     }
 
-  init = cxx_eval_constant_expression (&new_ctx, init, false,
-				       non_constant_p, overflow_p);
   /* Don't share a CONSTRUCTOR that might be changed later.  */
   init = unshare_constructor (init);
-  if (target == object)
-    /* The hash table might have moved since the get earlier.  */
-    valp = ctx->values->get (object);
 
-  if (TREE_CODE (init) == CONSTRUCTOR)
+  if (*valp && TREE_CODE (*valp) == CONSTRUCTOR
+      && TREE_CODE (init) == CONSTRUCTOR)
     {
       /* An outer ctx->ctor might be pointing to *valp, so replace
 	 its contents.  */
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-89336-1.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-89336-1.C
new file mode 100644
index 00000000000..93fe16551a1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-89336-1.C
@@ -0,0 +1,35 @@
+// PR c++/89336
+// { dg-do compile { target c++14 } }
+
+template <typename T, int N> struct A {
+  T a[N];
+  constexpr T &operator[] (int x) { return a[x]; }
+  constexpr const T &operator[] (int x) const { return a[x]; }
+};
+
+constexpr A<int, 16>
+foo ()
+{
+  A<int, 16> r{};
+  for (int i = 0; i < 6; ++i)
+    r[i + 8] = r[i] = i + 1;
+  return r;
+}
+
+constexpr auto x = foo ();
+static_assert (x[0] == 1, "");
+static_assert (x[1] == 2, "");
+static_assert (x[2] == 3, "");
+static_assert (x[3] == 4, "");
+static_assert (x[4] == 5, "");
+static_assert (x[5] == 6, "");
+static_assert (x[6] == 0, "");
+static_assert (x[7] == 0, "");
+static_assert (x[8] == 1, "");
+static_assert (x[9] == 2, "");
+static_assert (x[10] == 3, "");
+static_assert (x[11] == 4, "");
+static_assert (x[12] == 5, "");
+static_assert (x[13] == 6, "");
+static_assert (x[14] == 0, "");
+static_assert (x[15] == 0, "");
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-89336-2.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-89336-2.C
new file mode 100644
index 00000000000..69889ffb2b4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-89336-2.C
@@ -0,0 +1,56 @@
+// PR c++/89336
+// { dg-do compile { target c++14 } }
+
+constexpr int
+foo ()
+{
+  int a[16] = {};
+  int r = 0;
+  a[15] = a[14] = a[13] = a[12] = a[11] = a[10] = a[9] = a[8]
+    = a[7] = a[6] = a[5] = a[4] = a[3] = a[2] = a[1] = a[0] = 5;
+  for (int i = 0; i < 16; ++i)
+    r += a[i];
+  return r;
+}
+
+static_assert (foo () == 16 * 5, "");
+
+struct A { int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p; };
+
+constexpr int
+bar ()
+{
+  A a {};
+  a.p = a.o = a.n = a.m = a.l = a.k = a.j = a.i
+    = a.h = a.g = a.f = a.e = a.d = a.c = a.b = a.a = 8;
+  return a.a + a.b + a.c + a.d + a.e + a.f + a.g + a.h
+	 + a.i + a.j + a.k + a.l + a.m + a.n + a.o + a.p;
+}
+
+static_assert (bar () == 16 * 8, "");
+
+constexpr int
+baz ()
+{
+  int a[16] = {};
+  int r = 0;
+  a[0] = a[1] = a[2] = a[3] = a[4] = a[5] = a[6] = a[7]
+    = a[8] = a[9] = a[10] = a[11] = a[12] = a[13] = a[14] = a[15] = 7;
+  for (int i = 0; i < 16; ++i)
+    r += a[i];
+  return r;
+}
+
+static_assert (baz () == 16 * 7, "");
+
+constexpr int
+qux ()
+{
+  A a {};
+  a.a = a.b = a.c = a.d = a.e = a.f = a.g = a.h
+    = a.i = a.j = a.k = a.l = a.m = a.n = a.o = a.p = 6;
+  return a.a + a.b + a.c + a.d + a.e + a.f + a.g + a.h
+	 + a.i + a.j + a.k + a.l + a.m + a.n + a.o + a.p;
+}
+
+static_assert (qux () == 16 * 6, "");