From: Junio C Hamano <gitster@pobox.com>
To: Stephan Beyer <s-beyer@gmx.net>
Cc: Paul Tan <pyokagan@gmail.com>, Jeff King <peff@peff.net>,
"brian m. carlson" <sandals@crustytoothpaste.net>,
"Shawn O. Pearce" <spearce@spearce.org>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>,
git@vger.kernel.org
Subject: Re: [PATCH] Fix maybe-uninitialized warnings found by gcc 9 -flto
Date: Thu, 05 Sep 2019 10:56:12 -0700 [thread overview]
Message-ID: <xmqqd0ger5j7.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20190905082459.26816-1-s-beyer@gmx.net> (Stephan Beyer's message of "Thu, 5 Sep 2019 10:24:59 +0200")
Stephan Beyer <s-beyer@gmx.net> writes:
> diff --git a/t/helper/test-read-cache.c b/t/helper/test-read-cache.c
> index 7e79b555de..ef0963e2f4 100644
> --- a/t/helper/test-read-cache.c
> +++ b/t/helper/test-read-cache.c
> @@ -4,7 +4,7 @@
>
> int cmd__read_cache(int argc, const char **argv)
> {
> - int i, cnt = 1, namelen;
> + int i, cnt = 1, namelen = 0;
> const char *name = NULL;
>
> if (argc > 1 && skip_prefix(argv[1], "--print-and-refresh=", &name)) {
namelen = strlen(name);
The above is the only assignment to namelen in this function, and
namelen is used like so:
if (name) {
...
pos = index_name_pos(&the_index, name, namelen);
So somebody does not realize that skip_prefix() returns true only
when it touches name. But skip_prefix() is inline and visible to
the compiler, and it is quite clear that name is only touched when
the function returns non-zero.
static inline int skip_prefix(const char *str, const char *prefix,
const char **out)
{
do {
if (!*prefix) {
*out = str;
return 1;
}
} while (*str++ == *prefix++);
return 0;
}
So it looks like it is another case of compiler getting confused.
next prev parent reply other threads:[~2019-09-05 17:56 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 8:24 [PATCH] Fix maybe-uninitialized warnings found by gcc 9 -flto Stephan Beyer
2019-09-05 17:08 ` René Scharfe
2019-09-05 17:53 ` Jeff King
2019-09-05 19:09 ` René Scharfe
2019-09-05 19:25 ` Junio C Hamano
2019-09-05 19:39 ` René Scharfe
2019-09-05 19:50 ` Junio C Hamano
2019-09-05 17:41 ` Junio C Hamano
2019-09-05 17:56 ` Junio C Hamano [this message]
2019-09-05 18:03 ` Jeff King
2019-09-05 18:22 ` Junio C Hamano
2019-09-05 22:48 ` Jeff King
2019-09-05 22:50 ` [PATCH 1/6] git-am: handle missing "author" when parsing commit Jeff King
2019-09-05 22:52 ` [PATCH 2/6] pack-objects: use object_id in packlist_alloc() Jeff King
2019-09-05 22:52 ` [PATCH 3/6] bulk-checkin: zero-initialize hashfile_checkpoint Jeff King
2019-09-05 22:53 ` [PATCH 4/6] diff-delta: set size out-parameter to 0 for NULL delta Jeff King
2019-09-05 22:53 ` [PATCH] Fix maybe-uninitialized warnings found by gcc 9 -flto Stephan Beyer
2019-09-05 22:58 ` Jeff King
2019-09-05 23:10 ` Stephan Beyer
2019-09-06 1:24 ` Jeff King
2019-09-06 1:36 ` [PATCH v2 6/6] pack-objects: drop packlist index_pos optimization Jeff King
2019-09-05 22:54 ` [PATCH 5/6] test-read-cache: drop namelen variable Jeff King
2019-09-05 22:56 ` [PATCH 6/6] pack-objects: drop packlist index_pos optimization Jeff King
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