c++: TARGET_EXPR location in default arg [PR96997]

My r14-6505-g52b4b7d7f5c7c0 change to copy the location in
build_aggr_init_expr reopened PR96997; let's fix it properly this time, by
clearing the location like we do for other trees.

	PR c++/96997

gcc/cp/ChangeLog:

	* tree.cc (bot_manip): Check data.clear_location for TARGET_EXPR.

gcc/testsuite/ChangeLog:

	* g++.dg/debug/cleanup2.C: New test.

gcc/cp/tree.cc

@@ -3170,6 +3170,9 @@ bot_manip (tree* tp, int* walk_subtrees, void* data_)
       if (TREE_OPERAND (u, 1) == error_mark_node)
 	return error_mark_node;
 
+      if (data.clear_location)
+	SET_EXPR_LOCATION (u, input_location);
+
       /* Replace the old expression with the new version.  */
       *tp = u;
       /* We don't have to go below this point; the recursive call to

gcc/testsuite/g++.dg/debug/cleanup2.C

@@ -0,0 +1,10 @@
+// PR c++/96997
+// { dg-additional-options "-g -fdump-tree-gimple-lineno" }
+
+struct A { A(); ~A(); };
+void f(const A& = A());
+int main() { f(); }
+
+// The destructor call for the A temporary should not have the location of the
+// f declaration.
+// { dg-final { scan-tree-dump-not ".C:5" "gimple" } }