We were failing to give "defined but not used" warning for functions marked
with the attribute noreturn/volatile. The problem is that for functions the
TREE_THIS_VOLATILE flag means something different than for decls. The fix is
to check the flag only for VAR_DECLs, as suggested by Richi in the PR.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2015-12-01 Marek Polacek <pola...@redhat.com>
PR middle-end/68582
* cgraphunit.c (check_global_declaration): Only depend on
TREE_THIS_VOLATILE
for VAR_DECLs.
* c-c++-common/pr68582.c: New test.
diff --git gcc/cgraphunit.c gcc/cgraphunit.c
index f73d9a7..4ce5f9b 100644
--- gcc/cgraphunit.c
+++ gcc/cgraphunit.c
@@ -956,7 +956,7 @@ check_global_declaration (symtab_node *snode)
&& ! DECL_ABSTRACT_ORIGIN (decl)
&& ! TREE_PUBLIC (decl)
/* A volatile variable might be used in some non-obvious way. */
- && ! TREE_THIS_VOLATILE (decl)
+ && (! VAR_P (decl) || ! TREE_THIS_VOLATILE (decl))
/* Global register variables must be declared to reserve them. */
&& ! (TREE_CODE (decl) == VAR_DECL && DECL_REGISTER (decl))
/* Global ctors and dtors are called by the runtime. */
diff --git gcc/testsuite/c-c++-common/pr68582.c
gcc/testsuite/c-c++-common/pr68582.c
index e69de29..95ca9a4 100644
--- gcc/testsuite/c-c++-common/pr68582.c
+++ gcc/testsuite/c-c++-common/pr68582.c
@@ -0,0 +1,25 @@
+/* PR middle-end/68582 */
+/* { dg-do compile } */
+/* { dg-options "-Wunused-function" } */
+
+/* We failed to give the warning for functions with TREE_THIS_VOLATILE set. */
+
+static void
+fn1 (void) /* { dg-warning "defined but not used" } */
+{
+ __builtin_abort ();
+}
+
+__attribute__ ((noreturn))
+static void
+fn2 (void) /* { dg-warning "defined but not used" } */
+{
+ __builtin_abort ();
+}
+
+__attribute__ ((volatile))
+static void
+fn3 (void) /* { dg-warning "defined but not used" } */
+{
+ __builtin_abort ();
+}
Marek
