[PATCH] Fix PR80171

[Richard Biener <rguenther at suse dot de>]

Bootstrapped / tested on x86_64-unknown-linux-gnu, applied.

Richard.

2017-03-27  Richard Biener  <rguenther@suse.de>

	PR middle-end/80171
	* gimple-fold.c (fold_ctor_reference): Properly guard against
	NULL return value from canonicalize_constructor_val.

	* g++.dg/torture/pr80171.C: New testcase.

Index: gcc/gimple-fold.c
===================================================================
--- gcc/gimple-fold.c	(revision 246437)
+++ gcc/gimple-fold.c	(working copy)
@@ -6239,9 +6239,12 @@ fold_ctor_reference (tree type, tree cto
       && !compare_tree_int (TYPE_SIZE (TREE_TYPE (ctor)), size))
     {
       ret = canonicalize_constructor_val (unshare_expr (ctor), from_decl);
-      ret = fold_unary (VIEW_CONVERT_EXPR, type, ret);
       if (ret)
-	STRIP_USELESS_TYPE_CONVERSION (ret);
+	{
+	  ret = fold_unary (VIEW_CONVERT_EXPR, type, ret);
+	  if (ret)
+	    STRIP_USELESS_TYPE_CONVERSION (ret);
+	}
       return ret;
     }
   /* For constants and byte-aligned/sized reads try to go through
Index: gcc/testsuite/g++.dg/torture/pr80171.C
===================================================================
--- gcc/testsuite/g++.dg/torture/pr80171.C	(nonexistent)
+++ gcc/testsuite/g++.dg/torture/pr80171.C	(working copy)
@@ -0,0 +1,183 @@
+// { dg-do compile }
+
+template <typename> struct remove_reference;
+template <typename _Tp> struct remove_reference<_Tp &> { typedef _Tp type; };
+template <typename _Tp> typename remove_reference<_Tp>::type move(_Tp &&p1) {
+  return static_cast<typename remove_reference<_Tp>::type &&>(p1);
+}
+void *operator new(__SIZE_TYPE__, void *p2) { return p2; }
+struct Trans_NS__v1_GenericTlv {
+  virtual int getMinimumValueLength();
+  virtual unsigned long getValueLength() const;
+};
+struct IPv4NeighborAddressSubTlv;
+struct Trans_NS__v1_GenericTlvBase : Trans_NS__v1_GenericTlv {
+  virtual bool operator==(const IPv4NeighborAddressSubTlv &) const;
+};
+struct Trans_NS__v1_GenericUnsupportedTlv;
+template <typename> struct backup_holder {
+  Trans_NS__v1_GenericUnsupportedTlv *backup_;
+  Trans_NS__v1_GenericUnsupportedTlv &get() { return *backup_; }
+};
+template <typename> struct make_reference_content {
+  typedef IPv4NeighborAddressSubTlv type;
+};
+template <typename> struct unwrap_recursive {
+  typedef IPv4NeighborAddressSubTlv type;
+};
+template <typename> struct begin_impl;
+template <typename Sequence> struct begin {
+  typedef typename Sequence::tag tag_;
+  typedef typename begin_impl<tag_>::template apply<Sequence>::type type;
+};
+struct long_ {
+  static const int value = 0;
+};
+template <typename> struct O1_size_impl;
+template <typename Sequence>
+struct O1_size
+    : O1_size_impl<typename Sequence::tag>::template apply<Sequence> {};
+template <typename F, typename T2>
+struct apply_wrap2 : F::template apply<int, T2> {};
+template <int, typename, typename> struct iter_fold_impl;
+template <typename First, typename ForwardOp>
+struct iter_fold_impl<0, First, ForwardOp> {
+  typedef typename apply_wrap2<ForwardOp, First>::type state;
+};
+template <typename Sequence, typename ForwardOp> struct iter_fold {
+  typedef
+      typename iter_fold_impl<O1_size<Sequence>::value,
+                              typename begin<Sequence>::type, ForwardOp>::state
+          type;
+};
+template <typename> struct deref;
+template <typename T1> struct pair { typedef T1 first; };
+struct make_initializer_node {
+  template <typename, typename Iterator> struct apply {
+    struct initializer_node {
+      typedef typename deref<Iterator>::type recursive_enabled_T;
+      static int
+      initialize(void *p1,
+                 typename unwrap_recursive<recursive_enabled_T>::type) {
+        new (p1) typename make_reference_content<recursive_enabled_T>::type;
+      }
+    };
+    typedef pair<initializer_node> type;
+  };
+};
+struct l_item {
+  typedef int tag;
+  typedef l_item type;
+  typedef long_ size;
+  typedef int item;
+};
+template <> struct O1_size_impl<int> {
+  template <typename List> struct apply : List::size {};
+};
+template <typename> struct l_iter;
+template <typename Node> struct deref<l_iter<Node>> {
+  typedef typename Node::item type;
+};
+template <> struct begin_impl<int> {
+  template <typename List> struct apply {
+    typedef l_iter<typename List::type> type;
+  };
+};
+template <typename, typename, typename, typename, typename, typename, typename>
+struct list : l_item {};
+template <typename... T> struct make_variant_list { typedef list<T...> type; };
+template <typename T> T cast_storage(void *p1) { return *static_cast<T *>(p1); }
+struct visitation_impl_step {
+  typedef Trans_NS__v1_GenericUnsupportedTlv type;
+};
+template <typename Visitor, typename VoidPtrCV, typename T>
+void visitation_impl_invoke_impl(Visitor p1, VoidPtrCV p2, T *) {
+  backup_holder<Trans_NS__v1_GenericUnsupportedTlv> __trans_tmp_8 =
+      cast_storage<backup_holder<T>>(p2);
+  p1.internal_visit(__trans_tmp_8, 0);
+}
+template <typename Visitor, typename VoidPtrCV, typename T,
+          typename NoBackupFlag>
+void visitation_impl_invoke(Visitor p1, VoidPtrCV p2, T p3, NoBackupFlag) {
+  visitation_impl_invoke_impl(p1, p2, p3);
+}
+template <typename Which, typename step0, typename Visitor, typename VoidPtrCV,
+          typename NoBackupFlag>
+void visitation_impl(Visitor p1, VoidPtrCV p2, NoBackupFlag, Which, step0 *) {
+  visitation_impl_invoke(p1, p2, static_cast<typename step0::type *>(0), 0);
+}
+struct move_into {
+  move_into(void *);
+  template <typename T> void internal_visit(backup_holder<T> p1, int) {
+    T __trans_tmp_2 = p1.get();
+    new (0) T(__trans_tmp_2);
+  }
+};
+template <typename, typename... TN> struct variant {
+  struct initializer : iter_fold<typename make_variant_list<int, TN...>::type,
+                                 make_initializer_node>::type::first {};
+  template <typename T> void convert_construct(T p1, int) {
+    void *__trans_tmp_9 = this;
+    initializer::initialize(__trans_tmp_9, p1);
+  }
+  template <typename T> variant(T p1) { convert_construct(p1, 0); }
+  variant(variant &&p1) {
+    move_into visitor(0);
+    p1.internal_apply_visitor(visitor);
+  }
+  template <typename Visitor> void internal_apply_visitor(Visitor p1) {
+    void *__trans_tmp_10 = this;
+    visitation_impl(p1, __trans_tmp_10, 0, 0,
+                    static_cast<visitation_impl_step *>(0));
+  }
+};
+template <class...> struct generic_element_tlvs;
+template <typename TlvConfig, class UnsupportedTlvClass, class TlvF,
+          class... TlvR>
+struct generic_element_tlvs<TlvConfig, UnsupportedTlvClass, TlvF, TlvR...> {
+  typedef variant<UnsupportedTlvClass, TlvF, TlvR...> variant_type;
+};
+template <typename, typename> struct Trans_NS__v1_GenericTlvContainer {
+  template <class TlvClass> void addTlv(const TlvClass &);
+};
+template <typename TlvConfig, typename ElementTlvs>
+template <class TlvClass>
+void Trans_NS__v1_GenericTlvContainer<TlvConfig, ElementTlvs>::addTlv(
+    const TlvClass &p1) {
+  typename ElementTlvs::variant_type wrap(p1);
+  move(wrap);
+}
+template <typename ElementTlvs>
+struct Trans_NS__v1_GenericContainerEntryBase
+    : Trans_NS__v1_GenericTlvContainer<int, ElementTlvs> {};
+template <class>
+struct Trans_NS__v1_GenericFixedLengthTlvBase : Trans_NS__v1_GenericTlvBase {
+  unsigned long getValueLength() const;
+};
+struct Trans_NS__v1_GenericUnsupportedTlv : Trans_NS__v1_GenericTlv {
+  long getHeaderLengthconst;
+};
+using isis_tlv_config = int;
+template <class... TlvClasses>
+using isis_element_tlvs =
+    generic_element_tlvs<isis_tlv_config, Trans_NS__v1_GenericUnsupportedTlv,
+                         TlvClasses...>;
+template <int, class, typename ElementTlvs>
+using ContainerEntryBase = Trans_NS__v1_GenericContainerEntryBase<ElementTlvs>;
+template <int, class ImplClass, int>
+using FixedLengthTlvBase = Trans_NS__v1_GenericFixedLengthTlvBase<ImplClass>;
+struct IPv4NeighborAddressSubTlv
+    : FixedLengthTlvBase<0, IPv4NeighborAddressSubTlv, 0> {
+  bool operator==(const IPv4NeighborAddressSubTlv &) const;
+};
+void test() {
+  ContainerEntryBase<
+      0, int,
+      isis_element_tlvs<
+          FixedLengthTlvBase<0, int, 0>, FixedLengthTlvBase<0, int, 0>,
+          IPv4NeighborAddressSubTlv, FixedLengthTlvBase<0, int, 0>,
+          FixedLengthTlvBase<0, int, 0>, FixedLengthTlvBase<0, int, 0>>>
+      isEntry;
+  IPv4NeighborAddressSubTlv nbAddressSubTlv;
+  isEntry.addTlv(nbAddressSubTlv);
+}