From f64e0c029c452c9fc508adebf18d0ceb3ffdc066 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 25 Oct 2016 13:23:44 -0400
Subject: [PATCH] constexpr.c (maybe_constant_init): Pull out
 TARGET_EXPR_INITIAL.

	* constexpr.c (maybe_constant_init): Pull out TARGET_EXPR_INITIAL.

	(cxx_eval_outermost_constant_expr): Don't return a CONSTRUCTOR
	with CONSTRUCTOR_NO_IMPLICIT_ZERO.
	(cxx_eval_call_expression): Clear CONSTRUCTOR_NO_IMPLICIT_ZERO.

From-SVN: r241531
---
 gcc/cp/ChangeLog                              |  7 +++++++
 gcc/cp/constexpr.c                            | 16 +++++++++++++++
 .../g++.dg/cpp0x/constexpr-static12.C         | 20 +++++++++++++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-static12.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9c876b812c2..1276d13ad70 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2016-10-25  Jason Merrill  <jason@redhat.com>
+
+	* constexpr.c (maybe_constant_init): Pull out TARGET_EXPR_INITIAL.
+	(cxx_eval_outermost_constant_expr): Don't return a CONSTRUCTOR
+	with CONSTRUCTOR_NO_IMPLICIT_ZERO.
+	(cxx_eval_call_expression): Clear CONSTRUCTOR_NO_IMPLICIT_ZERO.
+
 2016-10-25  Jakub Jelinek  <jakub@redhat.com>
 
 	* parser.c (cp_parser_postfix_expression): Adding missing break;.
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 8f7b7f34b64..1ebd647e7d1 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -1665,6 +1665,10 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
 	entry->result = result;
     }
 
+  /* The result of a constexpr function must be completely initialized.  */
+  if (TREE_CODE (result) == CONSTRUCTOR)
+    CONSTRUCTOR_NO_IMPLICIT_ZERO (result) = false;
+
   pop_cx_call_context ();
   return unshare_constructor (result);
 }
@@ -4483,6 +4487,16 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant,
       non_constant_p = true;
     }
 
+  if (TREE_CODE (r) == CONSTRUCTOR
+      && CONSTRUCTOR_NO_IMPLICIT_ZERO (r))
+    {
+      if (!allow_non_constant)
+	error ("%qE is not a constant expression because it refers to "
+	       "an incompletely initialized variable", t);
+      TREE_CONSTANT (r) = false;
+      non_constant_p = true;
+    }
+
   /* Technically we should check this for all subexpressions, but that
      runs into problems with our internal representation of pointer
      subtraction and the 5.19 rules are still in flux.  */
@@ -4781,6 +4795,8 @@ maybe_constant_init (tree t, tree decl)
     t = TREE_OPERAND (t, 0);
   if (TREE_CODE (t) == INIT_EXPR)
     t = TREE_OPERAND (t, 1);
+  if (TREE_CODE (t) == TARGET_EXPR)
+    t = TARGET_EXPR_INITIAL (t);
   if (!potential_nondependent_static_init_expression (t))
     /* Don't try to evaluate it.  */;
   else
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-static12.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-static12.C
new file mode 100644
index 00000000000..4faa8cfd108
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-static12.C
@@ -0,0 +1,20 @@
+// { dg-do compile { target c++11 } }
+// { dg-final { scan-assembler-not "_ZNSt10unique_ptrC1Ei" } }
+
+namespace std {
+  struct unique_ptr {
+    constexpr unique_ptr(int) : p() { }
+    ~unique_ptr() { }
+    void* p;
+  };
+}
+
+void f()
+{
+  static std::unique_ptr p(1);
+}
+
+int main()
+{
+  f();
+}
-- 
2.30.2