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From: "zfigura at codeweavers dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/111669] New: bogus -Wnonnull in conditionally executed code
Date: Tue, 03 Oct 2023 04:34:03 +0000 [thread overview]
Message-ID: <bug-111669-4@http.gcc.gnu.org/bugzilla/> (raw)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111669
Bug ID: 111669
Summary: bogus -Wnonnull in conditionally executed code
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: zfigura at codeweavers dot com
Target Milestone: ---
Created attachment 56032
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56032&action=edit
reduced testcase, compile with -O2 -Werror=nonnull
Sorry about the rather useless title, but I can't really figure out what
actually triggers this error. It seems to depend on some arcane combination of
optimizations.
I was able to reduce this down to a pretty minimal test case, attached here. It
may be possible to reduce it further but I couldn't easily find a way.
The actual code that triggers this is here [1]. lstrcpyA() and lstrcatA() are
trivial wrappers around strcpy/strcat. The NULL comes from get_search_path() at
line 192. The offending strcpy/strcat will never be reached if
GetWindowsDirectoryA() returns nonzero, which it always should. However, gcc
triggers a -Wnonnull warning anyway.
Interestingly, the original Wine code only triggers the warning with
-march=bdver2 (or other values of -march), but the reduced testcase triggers it
with no -march flags.
[1]
https://source.winehq.org/git/wine.git/blob/HEAD:/dlls/krnl386.exe16/file.c#l639
next reply other threads:[~2023-10-03 4:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-03 4:34 zfigura at codeweavers dot com [this message]
2023-10-04 1:44 ` [Bug middle-end/111669] " xry111 at gcc dot gnu.org
2023-10-04 1:46 ` xry111 at gcc dot gnu.org
2023-10-04 15:44 ` zfigura at codeweavers dot com
2023-10-05 5:42 ` xry111 at gcc dot gnu.org
2023-10-05 5:48 ` xry111 at gcc dot gnu.org
2023-10-05 6:05 ` zfigura at codeweavers dot com
2023-10-05 6:14 ` xry111 at gcc dot gnu.org
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