On Tue, Dec 1, 2015 at 3:47 PM, Marek Polacek <pola...@redhat.com> wrote:
> 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?
Ok.
Thanks.
Richard.
> 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
