From ffd99ef2488db55f3c772742371f17282f115265 Mon Sep 17 00:00:00 2001
From: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 8 Mar 2018 21:18:50 +0000
Subject: [PATCH] 	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.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@258370 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/cp/ChangeLog                              |  7 +++++++
 gcc/cp/call.c                                 |  4 ++++
 gcc/testsuite/ChangeLog                       |  3 +++
 gcc/testsuite/g++.dg/warn/Wunused-function4.C | 21 +++++++++++++++++++++
 4 files changed, 35 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/warn/Wunused-function4.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9dd7c179710..3c1e4c76a06 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2018-03-08  Jason Merrill  <jason@redhat.com>
+	    Jakub Jelinek  <jakub@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.
+
 2018-03-06  Jason Merrill  <jason@redhat.com>
 
 	* lambda.c (is_capture_proxy_with_ref): Remove.
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index f83d51f3457..fd6528fcaeb 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -7634,6 +7634,10 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
 
       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);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 32740bf3710..1917aef3cf1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2018-03-08  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/80598
+	* g++.dg/warn/Wunused-function4.C: New test.
+
 	PR inline-asm/84742
 	* gcc.target/i386/pr84742-1.c: New test.
 	* gcc.target/i386/pr84742-2.c: New test.
diff --git a/gcc/testsuite/g++.dg/warn/Wunused-function4.C b/gcc/testsuite/g++.dg/warn/Wunused-function4.C
new file mode 100644
index 00000000000..00d5d70fc90
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wunused-function4.C
@@ -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;
+}
-- 
2.11.4.GIT