tree-cfg.c (gimple_split_edge): Avoid reallocating target PHI nodes.

2017-08-22  Richard Biener  <rguenther@suse.de>

	* tree-cfg.c (gimple_split_edge): Avoid reallocating target
	PHI nodes.

From-SVN: r251264

gcc/ChangeLog

 2017-08-22  Richard Biener  <rguenther@suse.de>
 
+	* tree-cfg.c (gimple_split_edge): Avoid reallocating target
+	PHI nodes.
+
+2017-08-22  Richard Biener  <rguenther@suse.de>
+
 	* common.opt (feliminate-dwarf2-dups): Ignore.
 	* doc/invoke.texi (feliminate-dwarf2-dups): Remove documentation.
 	* dwarf2out.c (push_new_compile_unit, pop_compile_unit,

gcc/tree-cfg.c

@@ -2844,10 +2844,11 @@ gimple_split_edge (edge edge_in)
   new_bb = create_empty_bb (after_bb);
   new_bb->frequency = EDGE_FREQUENCY (edge_in);
   new_bb->count = edge_in->count;
-  new_edge = make_single_succ_edge (new_bb, dest, EDGE_FALLTHRU);
 
   e = redirect_edge_and_branch (edge_in, new_bb);
   gcc_assert (e == edge_in);
+
+  new_edge = make_single_succ_edge (new_bb, dest, EDGE_FALLTHRU);
   reinstall_phi_args (new_edge, e);
 
   return new_bb;