Ping.
On Thu, Sep 29, 2016 at 06:10:27PM +0200, Marek Polacek wrote:
> Here, a missing -Wimplicit-fallthrough warning was caused by a misplaced
> FALLTHROUGH_LABEL_P check. As it is now, for FALLTHROUGH_LABEL_P we'd
> never gotten around to
> 1933 /* So that next warn_implicit_fallthrough_r will start
> looking for
> 1934 a new sequence starting with this label. */
> 1935 gsi_prev (gsi_p);
>
> The fix is to move the check to should_warn_for_implicit_fallthrough.
>
> Bootstrapped/regtested on x86_64-linux and ppc64-linux, ok for trunk?
>
> 2016-09-29 Marek Polacek <pola...@redhat.com>
>
> * gimplify.c (should_warn_for_implicit_fallthrough): Check for
> FALLTHROUGH_LABEL_P here...
> (warn_implicit_fallthrough_r): ...not here.
>
> * c-c++-common/Wimplicit-fallthrough-22.c: New test.
>
> diff --git gcc/gimplify.c gcc/gimplify.c
> index 66bb8be..e077a7e 100644
> --- gcc/gimplify.c
> +++ gcc/gimplify.c
> @@ -1817,6 +1817,10 @@ should_warn_for_implicit_fallthrough
> (gimple_stmt_iterator *gsi_p, tree label)
> {
> gimple_stmt_iterator gsi = *gsi_p;
>
> + /* Don't warn if the label is marked with a "falls through" comment. */
> + if (FALLTHROUGH_LABEL_P (label))
> + return false;
> +
> /* Don't warn for a non-case label followed by a statement:
> case 0:
> foo ();
> @@ -1903,7 +1907,6 @@ warn_implicit_fallthrough_r (gimple_stmt_iterator
> *gsi_p, bool *handled_ops_p,
> if (gimple_code (next) == GIMPLE_LABEL
> && gimple_has_location (next)
> && (label = gimple_label_label (as_a <glabel *> (next)))
> - && !FALLTHROUGH_LABEL_P (label)
> && prev != NULL)
> {
> struct label_entry *l;
> diff --git gcc/testsuite/c-c++-common/Wimplicit-fallthrough-22.c
> gcc/testsuite/c-c++-common/Wimplicit-fallthrough-22.c
> index e69de29..7a81e47 100644
> --- gcc/testsuite/c-c++-common/Wimplicit-fallthrough-22.c
> +++ gcc/testsuite/c-c++-common/Wimplicit-fallthrough-22.c
> @@ -0,0 +1,23 @@
> +/* { dg-do compile } */
> +/* { dg-options "-Wimplicit-fallthrough" } */
> +
> +void bar (int);
> +
> +void
> +foo (int i)
> +{
> + switch (i)
> + {
> + case 1:
> + bar (1);
> + /* FALLTHROUGH */
> + case 2:
> + bar (2); /* { dg-warning "statement may fall through" } */
> + case 3:
> + bar (3); /* { dg-warning "statement may fall through" } */
> + case 4:
> + bar (4);
> + default:
> + break;
> + }
> +}
>
> Marek
Marek
