From d276da0cf5bff87311330b395d3918b569bbbcc3 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 20 Jun 2017 12:47:17 -0400
Subject: [PATCH] PR c++/80972 - C++17 ICE with attribute packed.

	* call.c (build_over_call): Allow a TARGET_EXPR from reference
	binding.

From-SVN: r249420
---
 gcc/cp/ChangeLog                    | 6 ++++++
 gcc/cp/call.c                       | 2 ++
 gcc/testsuite/g++.dg/ext/packed12.C | 6 ++++++
 3 files changed, 14 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/packed12.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 5786cbaea2a..01230c09f02 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2017-06-20  Jason Merrill  <jason@redhat.com>
+
+	PR c++/80972 - C++17 ICE with attribute packed.
+	* call.c (build_over_call): Allow a TARGET_EXPR from reference
+	binding.
+
 2017-06-20  Nathan Sidwell  <nathan@acm.org>
 
 	* cp-tree.h (CPTI_NELTS_IDENTIFIER): Delete.
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index d1f27dde830..b56da353519 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -8025,6 +8025,8 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
 	 subobject.  */
       if (CHECKING_P && cxx_dialect >= cxx1z)
 	gcc_assert (TREE_CODE (arg) != TARGET_EXPR
+		    /* It's from binding the ref parm to a packed field. */
+		    || convs[0]->need_temporary_p
 		    || seen_error ()
 		    /* See unsafe_copy_elision_p.  */
 		    || DECL_BASE_CONSTRUCTOR_P (fn));
diff --git a/gcc/testsuite/g++.dg/ext/packed12.C b/gcc/testsuite/g++.dg/ext/packed12.C
new file mode 100644
index 00000000000..2ad14de102d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/packed12.C
@@ -0,0 +1,6 @@
+// PR c++/80972
+
+struct A { int i; };
+struct B { A a; } __attribute__((packed));
+
+A a = B().a;