From c4210852f1e7f5aa901411a3f82059d54d2287c8 Mon Sep 17 00:00:00 2001
From: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 22 Feb 2018 22:50:37 +0000
Subject: [PATCH] 	PR c++/84424 - ICE with constexpr and
 __builtin_shuffle.

	* constexpr.c (reduced_constant_expression_p): Handle CONSTRUCTOR of
	VECTOR_TYPE.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@257924 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/cp/ChangeLog                    | 6 ++++++
 gcc/cp/constexpr.c                  | 8 +++++++-
 gcc/testsuite/g++.dg/ext/vector34.C | 8 ++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/ext/vector34.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index f38f662f8f5..79b7f00644d 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2018-02-22  Jason Merrill  <jason@redhat.com>
+
+	PR c++/84424 - ICE with constexpr and __builtin_shuffle.
+	* constexpr.c (reduced_constant_expression_p): Handle CONSTRUCTOR of
+	VECTOR_TYPE.
+
 2018-02-22  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/84493
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index f095b038d32..47ff90cb055 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -1763,7 +1763,13 @@ reduced_constant_expression_p (tree t)
       /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR.  */
       tree idx, val, field; unsigned HOST_WIDE_INT i;
       if (CONSTRUCTOR_NO_IMPLICIT_ZERO (t))
-	field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t)));
+	{
+	  if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
+	    /* An initialized vector would have a VECTOR_CST.  */
+	    return false;
+	  else
+	    field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t)));
+	}
       else
 	field = NULL_TREE;
       FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val)
diff --git a/gcc/testsuite/g++.dg/ext/vector34.C b/gcc/testsuite/g++.dg/ext/vector34.C
new file mode 100644
index 00000000000..5cca53070b2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/vector34.C
@@ -0,0 +1,8 @@
+// PR c++/84424
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+typedef int vec __attribute__ ((vector_size (2 * sizeof (int))));
+
+constexpr vec u = { 1, 2 };
+constexpr vec v = __builtin_shuffle (v, u); // { dg-error "" }
-- 
2.11.4.GIT