From: Marek Polacek <polacek@redhat.com>
To: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Fix missing -Wimplicit-fallthrough warning
Date: Thu, 29 Sep 2016 16:26:00 -0000 [thread overview]
Message-ID: <20160929161027.GT3223@redhat.com> (raw)
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 <polacek@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
next reply other threads:[~2016-09-29 16:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-29 16:26 Marek Polacek [this message]
2016-10-05 16:53 ` Marek Polacek
2016-10-07 12:30 ` Jakub Jelinek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160929161027.GT3223@redhat.com \
--to=polacek@redhat.com \
--cc=gcc-patches@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).