From 97fabbc141bc3fd97a10205a062620f5cccab0c9 Mon Sep 17 00:00:00 2001
From: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 12 Oct 2017 07:23:24 +0000
Subject: [PATCH] 	PR c++/82159 	* expr.c (store_field): Don't optimize
 away bitsize == 0 store 	from CALL_EXPR with addressable return type.

	* g++.dg/opt/pr82159-2.C: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@253673 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog                        |  6 ++++
 gcc/expr.c                           |  7 ++--
 gcc/testsuite/ChangeLog              |  3 ++
 gcc/testsuite/g++.dg/opt/pr82159-2.C | 65 ++++++++++++++++++++++++++++++++++++
 4 files changed, 79 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/opt/pr82159-2.C

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 40fa8f5a2e6..12cf2d30475 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-12  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/82159
+	* expr.c (store_field): Don't optimize away bitsize == 0 store
+	from CALL_EXPR with addressable return type.
+
 2017-10-11  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	* config/rs6000/rs6000.h (TARGET_ISEL64): Delete.
diff --git a/gcc/expr.c b/gcc/expr.c
index d2e4d042f1b..1bba9330cd3 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -6749,8 +6749,11 @@ store_field (rtx target, HOST_WIDE_INT bitsize, HOST_WIDE_INT bitpos,
     return const0_rtx;
 
   /* If we have nothing to store, do nothing unless the expression has
-     side-effects.  */
-  if (bitsize == 0)
+     side-effects.  Don't do that for zero sized addressable lhs of
+     calls.  */
+  if (bitsize == 0
+      && (!TREE_ADDRESSABLE (TREE_TYPE (exp))
+	  || TREE_CODE (exp) != CALL_EXPR))
     return expand_expr (exp, const0_rtx, VOIDmode, EXPAND_NORMAL);
 
   if (GET_CODE (target) == CONCAT)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c0d873daf0f..eaf1ce59531 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2017-10-12  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/82159
+	* g++.dg/opt/pr82159-2.C: New test.
+
 	PR target/82353
 	* gcc.target/i386/i386.exp (tests): Revert the '.C' extension change.
 	* gcc.target/i386/pr82353.C: Moved to ...
diff --git a/gcc/testsuite/g++.dg/opt/pr82159-2.C b/gcc/testsuite/g++.dg/opt/pr82159-2.C
new file mode 100644
index 00000000000..f153c29ddac
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr82159-2.C
@@ -0,0 +1,65 @@
+// PR c++/82159
+// { dg-do compile }
+// { dg-options "" }
+
+template <typename T> struct D { T e; };
+struct F : D<int[0]> {
+  F(const F &);
+};
+struct G : F {
+  template <class T> G operator-(T);
+};
+template <class T> struct I {
+  typedef typename T::template J<I> ak;
+};
+template <class T> struct K { typename I<T>::ak an; };
+struct H {
+  G l;
+};
+struct C {
+  ~C();
+};
+template <class T> struct M : T {
+  template <typename U, typename V> M(U, V);
+  H h;
+  virtual void foo() { T::bar(&h); }
+};
+template <int, typename> class A;
+template <class> struct B {
+  typedef int BT;
+  struct BC {};
+  template <class T> struct BD {
+    G g;
+    BD(BT, T n) : g(n.l - 0) {}
+  };
+  B(BT, BC);
+};
+template <typename> struct O;
+template <int T, typename U>
+struct O<B<A<T, U> > > : public B<A<T, U> >::BC {};
+struct L : B<A<2, double> > {
+  struct P : C {
+    void bar(H *x) {
+      BT a;
+      BD<H>(a, *x);
+    }
+  };
+  template <typename U, typename V> L(U x, V n) : B(x, n) {}
+  int ll;
+  virtual int baz() { M<P>(this, ll); }
+};
+template <typename> class Q {
+  O<B<A<2, double> > > q;
+  virtual L baz() { L(0, q); }
+};
+template <template <class> class T> struct R {
+  R() { T<int>(); }
+};
+struct S {
+  template <class> class J : R<Q> {};
+};
+void foo() { K<S> c; }
+
+int main() {
+  return 0;
+}
-- 
2.11.4.GIT