From 6df911fd1d0f8d697b3a133a8c48a2ecb46f1dd0 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Mon, 18 Sep 2017 14:33:58 -0400
Subject: [PATCH] PR c++/72457 - ICE with list-value-initialized base.

	* init.c (expand_aggr_init_1): Only handle value-init of bases.
	* constexpr.c (build_data_member_initialization): Handle multiple
	initializers for the same field.

From-SVN: r252938
---
 gcc/cp/ChangeLog                             |  5 +++++
 gcc/cp/constexpr.c                           |  7 ++++++-
 gcc/cp/init.c                                |  6 +++---
 gcc/testsuite/g++.dg/cpp0x/constexpr-list1.C | 15 +++++++++++++++
 4 files changed, 29 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-list1.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index f8c3a89fc980..f78bce6be987 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,10 @@
 2017-09-18  Jason Merrill  <jason@redhat.com>
 
+	PR c++/72457
+	* init.c (expand_aggr_init_1): Only handle value-init of bases.
+	* constexpr.c (build_data_member_initialization): Handle multiple
+	initializers for the same field.
+
 	PR c++/55922
 	PR c++/63151
 	* init.c (expand_aggr_init_1): Handle list-initialization from {}.
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index b996e98027fb..3f37cd50fcf2 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -401,7 +401,12 @@ build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec)
 	gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node);
     }
 
-  CONSTRUCTOR_APPEND_ELT (*vec, member, init);
+  /* Value-initialization can produce multiple initializers for the
+     same field; use the last one.  */
+  if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member)
+    (*vec)->last().value = init;
+  else
+    CONSTRUCTOR_APPEND_ELT (*vec, member, init);
   return true;
 }
 
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 98caa9556ca8..841afbd8f518 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1811,9 +1811,9 @@ expand_aggr_init_1 (tree binfo, tree true_exp, tree exp, tree init, int flags,
     }
 
   /* List-initialization from {} becomes value-initialization for non-aggregate
-     classes with default constructors.  Handle this here so protected access
-     works.  */
-  if (init && TREE_CODE (init) == TREE_LIST)
+     classes with default constructors.  Handle this here when we're
+     initializing a base, so protected access works.  */
+  if (exp != true_exp && init && TREE_CODE (init) == TREE_LIST)
     {
       tree elt = TREE_VALUE (init);
       if (DIRECT_LIST_INIT_P (elt)
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-list1.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-list1.C
new file mode 100644
index 000000000000..f831a112cc9a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-list1.C
@@ -0,0 +1,15 @@
+// PR c++/72457
+// { dg-do compile { target c++11 } }
+
+struct A {
+  int i;
+  constexpr A(): i(0) {}
+};
+
+struct B: A { };
+
+struct C
+{
+  B b;
+  constexpr C() : b{} {}
+};
-- 
2.47.2