[PATCH] Fix another ICE with C++ addressable bitsize 0 return value (PR c++/82159)

[Jakub Jelinek]

Hi!

Another case where we ICE because we optimize away store to bitsize 0
addressable object from call.  We can't optimize them away, otherwise
we'd try to create the temporaries again and fail to do so.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2017-10-11  Jakub Jelinek  <ja...@redhat.com>

        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.

--- gcc/expr.c.jj       2017-10-10 22:04:06.000000000 +0200
+++ gcc/expr.c  2017-10-11 16:48:45.428536126 +0200
@@ -6749,8 +6749,11 @@ store_field (rtx target, HOST_WIDE_INT b
     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)
--- gcc/testsuite/g++.dg/opt/pr82159-2.C.jj     2017-10-11 17:27:18.050861346 
+0200
+++ gcc/testsuite/g++.dg/opt/pr82159-2.C        2017-10-11 17:27:27.081753330 
+0200
@@ -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;
+}

        Jakub