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[Bug c/60439] No warning for case overflow in switch statement.
- From: "chengniansun at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 13 Mar 2014 18:34:43 +0000
- Subject: [Bug c/60439] No warning for case overflow in switch statement.
- Auto-submitted: auto-generated
- References: <bug-60439-4 at http dot gcc dot gnu dot org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60439
--- Comment #3 from Chengnian Sun <chengniansun at gmail dot com> ---
(In reply to Marek Polacek from comment #2)
> Right. So I think there's nothing much to do. Please reopen if you
> strongly disagree.
Hi Marek,
>From the perspective of type system, I think no warning is fine. But from the
viewpoint of practice, IMHO this should be an overlooked case, as at runtime
there is indeed overflow.
The reason that I filed this report is not only that Clang emits a warning on
this issue (shown as below), but also that Gcc is able to handle the value
range of expressions (if I under the report PR60036 correctly).
-------------------------------------------------------------------
$: clang-trunk -Wswitch s.c -c
s.c:3:8: warning: overflow converting case value to switch condition type
(111111 to 7) [-Wswitch]
case 111111: return 1; /*warning here*/
^
s.c:8:3: warning: switch condition has boolean value
switch(c && d) {
^ ~~~~~~