On Thu, Mar 08, 2018 at 10:08:20AM -0500, Jason Merrill wrote:
> On Wed, Mar 7, 2018 at 5:19 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> > This testcase regressed when the mark_used call in finish_id_expression
> > has been guarded with if (done). Wonder if we can't just mark it TREE_USED
> > otherwise for the benefit of -Wunused-function and leave it
> > non-DECL_ODR_USED as it should. Or do we want to mark it TREE_USED
> > elsewhere?
>
> Probably in the processing_template_decl block near the top of
> build_over_call.
This works too. Ok for trunk then (passed bootstrap/regtest on x86_64-linux
and i686-linux)?
2018-03-08 Jason Merrill <ja...@redhat.com>
Jakub Jelinek <ja...@redhat.com>
PR c++/80598
* call.c (build_over_call): In templates set TREE_USED (first_fn) when
not calling mark_used for the benefit of -Wunused-function warning.
* g++.dg/warn/Wunused-function4.C: New test.
--- gcc/cp/call.c.jj 2018-03-08 10:58:58.157373982 +0100
+++ gcc/cp/call.c 2018-03-08 16:18:19.897340581 +0100
@@ -7634,6 +7634,10 @@ build_over_call (struct z_candidate *can
if (undeduced_auto_decl (fn))
mark_used (fn, complain);
+ else
+ /* Otherwise set TREE_USED for the benefit of -Wunused-function.
+ See PR80598. */
+ TREE_USED (fn) = 1;
return_type = TREE_TYPE (TREE_TYPE (fn));
nargs = vec_safe_length (args);
--- gcc/testsuite/g++.dg/warn/Wunused-function4.C.jj 2018-03-08
16:16:23.756274559 +0100
+++ gcc/testsuite/g++.dg/warn/Wunused-function4.C 2018-03-08
16:16:23.756274559 +0100
@@ -0,0 +1,21 @@
+// PR c++/80598
+// { dg-do compile }
+// { dg-options "-Wunused-function" }
+
+static void
+foo () // { dg-bogus "defined but not used" }
+{
+}
+
+static void
+bar () // { dg-warning "defined but not used" }
+{
+}
+
+template <class T>
+int
+baz (T x)
+{
+ foo ();
+ return 0;
+}
Jakub
