[C++ PATCH] Fix make_temporary_var_for_ref_to_temp (PR c++/86669)

[Jakub Jelinek <jakub at redhat dot com>]

On Wed, Dec 05, 2018 at 09:50:56PM +0100, Jakub Jelinek wrote:
> On Wed, Dec 05, 2018 at 03:49:26PM -0500, Jason Merrill wrote:
> > On 11/28/18 3:42 AM, Jakub Jelinek wrote:
> > > Whenever we need to clone a cdtor (either because the target doesn't support
> > > aliases the way we need, e.g. initlist105.C testcase on darwin, where it has
> > > been originally reported, or when it has virtual bases, like the made up
> > > initlist106.C on x86_64-linux), we rely on DECL_INITIAL of the local
> > > variables being unshared, because the tree unsharing gimplify.c performs
> > > doesn't unshare DECL_INITIAL.  clone_body has some code to recurse on the
> > > DECL_INITIAL, but it handles just decls FOR_EACH_LOCAL_DECL walks.  I
> > > believe it is generally ok that not all temporaries are covered in local
> > > decls, the gimplifier should take care of those fine if we don't need
> > > debug info for them.
> > 
> > I think any temporaries that have DECL_INITIAL should be pushed so that they
> > end up in local_decls.  set_up_extended_ref_temp already adds a DECL_EXPR
> > for it, I guess we need a pushdecl as well.  Though the comment for
> > get_temp_regvar suggests that this is problematic somehow.
> 
> Ok, will play with it tomorrow.

The following fixes the testcase too and passed bootstrap/regtest on
x86_64-linux and i686-linux, ok for trunk?

2018-12-07  Jakub Jelinek  <jakub@redhat.com>

	PR c++/86669
	* call.c (make_temporary_var_for_ref_to_temp): Call pushdecl even for
	automatic vars.

	* g++.dg/cpp0x/initlist105.C: New test.
	* g++.dg/cpp0x/initlist106.C: New test.
	* g++.dg/other/pr86669.C: New test.

--- gcc/cp/call.c.jj	2018-11-29 23:11:38.386646583 +0100
+++ gcc/cp/call.c	2018-12-06 13:50:26.766178596 +0100
@@ -11130,14 +11130,12 @@ make_temporary_var_for_ref_to_temp (tree
       tree name = mangle_ref_init_variable (decl);
       DECL_NAME (var) = name;
       SET_DECL_ASSEMBLER_NAME (var, name);
-
-      var = pushdecl (var);
     }
   else
     /* Create a new cleanup level if necessary.  */
     maybe_push_cleanup_level (type);
 
-  return var;
+  return pushdecl (var);
 }
 
 /* EXPR is the initializer for a variable DECL of reference or
--- gcc/testsuite/g++.dg/cpp0x/initlist105.C.jj	2018-12-06 13:31:35.993609689 +0100
+++ gcc/testsuite/g++.dg/cpp0x/initlist105.C	2018-12-06 13:31:35.993609689 +0100
@@ -0,0 +1,28 @@
+// PR c++/86669
+// { dg-do run { target c++11 } }
+
+#include <initializer_list>
+
+struct S { S (); };
+struct T : public S {};
+int cnt;
+void foo (int) { cnt++; }
+
+S::S ()
+{
+  int e = 1, f = 2, g = 3, h = 4;
+
+  for (auto k : { e, f, g, h })
+    foo (k);
+}
+
+int
+main ()
+{
+  S s;
+  if (cnt != 4)
+    __builtin_abort ();
+  T t;
+  if (cnt != 8)
+    __builtin_abort ();
+}
--- gcc/testsuite/g++.dg/cpp0x/initlist106.C.jj	2018-12-06 13:31:35.993609689 +0100
+++ gcc/testsuite/g++.dg/cpp0x/initlist106.C	2018-12-06 13:31:35.993609689 +0100
@@ -0,0 +1,29 @@
+// PR c++/86669
+// { dg-do run { target c++11 } }
+
+#include <initializer_list>
+
+struct A { };
+struct S : virtual public A { S (); };
+struct T : public S, virtual public A {};
+int cnt;
+void foo (int) { cnt++; }
+
+S::S ()
+{
+  int e = 1, f = 2, g = 3, h = 4;
+
+  for (auto k : { e, f, g, h })
+    foo (k);
+}
+
+int
+main ()
+{
+  S s;
+  if (cnt != 4)
+    __builtin_abort ();
+  T t;
+  if (cnt != 8)
+    __builtin_abort ();
+}
--- gcc/testsuite/g++.dg/other/pr86669.C.jj	2018-12-06 13:31:35.993609689 +0100
+++ gcc/testsuite/g++.dg/other/pr86669.C	2018-12-06 13:31:35.993609689 +0100
@@ -0,0 +1,10 @@
+// PR c++/86669
+// { dg-do compile }
+
+struct S { S (); };
+struct T : public S {};
+
+S::S ()
+{
+  int *p = { (int *) &p };
+}


	Jakub