PR c++/93173 - incorrect tree sharing.

My patch for 93033 wasn't sufficient to handle all the possible sharing
introduced by split_nonconstant_init, and it occurred to me that it would
make sense to use the same unsharing technique as unshare_body, namely
copy_if_shared.

	PR c++/93033
gcc/
	* gimplify.c (copy_if_shared): No longer static.
	* gimplify.h: Declare it.
gcc/cp/
	* cp-gimplify.c (cp_gimplify_init_expr, cp_gimplify_expr): Use
	copy_if_shared after cp_genericize_tree.
	* typeck2.c (split_nonconstant_init): Don't unshare here.

From-SVN: r280126

gcc/ChangeLog

+2020-01-10  Jason Merrill  <jason@redhat.com>
+
+	PR c++/93173 - incorrect tree sharing.
+	* gimplify.c (copy_if_shared): No longer static.
+	* gimplify.h: Declare it.
+
 2020-01-10  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* doc/invoke.texi (-msve-vector-bits=): Document that

gcc/cp/ChangeLog

+2020-01-10  Jason Merrill  <jason@redhat.com>
+
+	PR c++/93173 - incorrect tree sharing.
+	PR c++/93033
+	* cp-gimplify.c (cp_gimplify_init_expr, cp_gimplify_expr): Use
+	copy_if_shared after cp_genericize_tree.
+	* typeck2.c (split_nonconstant_init): Don't unshare here.
+
 2020-01-08  Jason Merrill  <jason@redhat.com>
 
 	* cp-gimplify.c (cp_gimplify_expr) [TARGET_EXPR]: Check

gcc/cp/cp-gimplify.c

@@ -537,6 +537,7 @@ cp_gimplify_init_expr (tree *expr_p, gimple_seq *pre_p)
       replace_placeholders (from, to);
       from = split_nonconstant_init (to, from);
       cp_genericize_tree (&from, false);
+      copy_if_shared (&from);
       *expr_p = from;
       return;
     }
@@ -712,6 +713,7 @@ cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 	hash_set<tree> pset;
 	cp_walk_tree (expr_p, cp_fold_r, &pset, NULL);
 	cp_genericize_tree (expr_p, false);
+	copy_if_shared (expr_p);
 	ret = GS_OK;
 	input_location = loc;
       }

gcc/cp/typeck2.c

@@ -34,7 +34,6 @@ 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,
@@ -792,8 +791,7 @@ split_nonconstant_init (tree dest, tree init)
 	}
       else if (init)
 	{
-	  tree ie = build2 (INIT_EXPR, void_type_node,
-			    unshare_expr (dest), init);
+	  tree ie = build2 (INIT_EXPR, void_type_node, dest, init);
 	  code = add_stmt_to_compound (ie, code);
 	}
     }

gcc/gimplify.c

@@ -937,7 +937,7 @@ copy_if_shared_r (tree *tp, int *walk_subtrees, void *data)
 /* Unshare most of the shared trees rooted at *TP.  DATA is passed to the
    copy_if_shared_r callback unmodified.  */
 
-static inline void
+void
 copy_if_shared (tree *tp, void *data)
 {
   walk_tree (tp, copy_if_shared_r, data, NULL);

gcc/gimplify.h

@@ -62,6 +62,7 @@ extern tree get_initialized_tmp_var (tree, gimple_seq *, gimple_seq * = NULL,
 extern void declare_vars (tree, gimple *, bool);
 extern void gimple_add_tmp_var (tree);
 extern void gimple_add_tmp_var_fn (struct function *, tree);
+extern void copy_if_shared (tree *, void * = NULL);
 extern tree unshare_expr (tree);
 extern tree unshare_expr_without_location (tree);
 extern tree voidify_wrapper_expr (tree, tree);

gcc/testsuite/g++.dg/cpp0x/initlist-new3.C

+// PR c++/93173
+// { dg-do compile { target c++11 } }
+
+template<typename> struct S1 {
+  S1(S1 &);
+  ~S1();
+};
+struct S2 {
+  S1<void> x;
+  int y;
+  int z;
+};
+void f(S1<void> x, int y, int z) { new S2{x, y, z}; }