PR c++/93033 - incorrect tree node sharing with array init.

The split_nonconstant_init piece is the only one necessary to fix the
testcase, but it occurred to me that we might as well not split when
-fno-exceptions.

	* typeck2.c (split_nonconstant_init): Unshare non-decl.
	* cp-gimplify.c (cp_gimplify_init_expr): Only split if -fexceptions.

From-SVN: r279871

gcc/cp/ChangeLog

@@ -1,3 +1,9 @@
+2020-01-03  Jason Merrill  <jason@redhat.com>
+
+	PR c++/93033 - incorrect tree node sharing with array init.
+	* typeck2.c (split_nonconstant_init): Unshare non-decl.
+	* cp-gimplify.c (cp_gimplify_init_expr): Only split if -fexceptions.
+
 2020-01-02  Jason Merrill  <jason@redhat.com>
 
 	* pt.c (invalid_nontype_parm_type_p): Reject class placeholder in

gcc/cp/cp-gimplify.c

@@ -529,6 +529,7 @@ cp_gimplify_init_expr (tree *expr_p, gimple_seq *pre_p)
   /* If we might need to clean up a partially constructed object, break down
      the CONSTRUCTOR with split_nonconstant_init.  */
   if (TREE_CODE (from) == CONSTRUCTOR
+      && flag_exceptions
       && TREE_SIDE_EFFECTS (from)
       && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (to)))
     {

gcc/cp/typeck2.c

@@ -34,6 +34,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "intl.h"
 #include "gcc-rich-location.h"
 #include "target.h"
+#include "gimplify.h"
 
 static tree
 process_init_constructor (tree type, tree init, int nested, int flags,
@@ -791,7 +792,8 @@ split_nonconstant_init (tree dest, tree init)
 	}
       else if (init)
 	{
-	  tree ie = build2 (INIT_EXPR, void_type_node, dest, init);
+	  tree ie = build2 (INIT_EXPR, void_type_node,
+			    unshare_expr (dest), init);
 	  code = add_stmt_to_compound (ie, code);
 	}
     }

gcc/testsuite/g++.dg/cpp0x/initlist-array9.C

@@ -0,0 +1,20 @@
+// PR c++/93033
+// { dg-do compile { target c++11 } }
+
+struct A {
+  A ();
+  ~A ();
+};
+
+A f();
+
+struct B {
+  A a;
+  bool b;
+};
+
+void
+foo ()
+{
+  B i[] { f() };
+}