https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115702
Bug ID: 115702
Summary: Incorrect stringop-overflow warning with -O3
Product: gcc
Version: 14.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: christian at zeek dot org
Target Milestone: ---
When compiling sqlite's all-in-one source file with -O3 it throws an erroneous
stringop-overread warning not present with -O2:
$ wget https://www.sqlite.org/2024/sqlite-amalgamation-3460000.zip
$ md5sum sqlite-amalgamation-3460000.zip
78c40a42c3d2e2a52ab011edb33e99cf sqlite-amalgamation-3460000.zip
$ unzip sqlite-amalgamation-3460000.zip
$ cd sqlite-amalgamation-3460000
$ gcc -c -Wall -O3 sqlite3.c
In function ‘sqlite3Strlen30’,
inlined from ‘sqlite3ColumnSetColl’ at sqlite3.c:122170:10:
sqlite3.c:35009:28: error: ‘strlen’ reading 1 or more bytes from a region of
size 0 [-Werror=stringop-overread]
35009 | return 0x3fffffff & (int)strlen(z);
| ^~~~~~~~~
In function ‘sqlite3ColumnSetColl’:
cc1: note: source object is likely at address zero
$
$ gcc -c -Wall -O2 sqlite3.c
$
Apologies for not reducing this to a manageable reproducer. I am not affiliated
with the sqlite3 project and just wanted to send a heads-up since we noticed
this in our project, which embeds their source, and uses -Werror. I could only
trigger this on sqlite's all-in-one source file, not the individual sources.
Discussion in the sqlite3 project:
https://www.sqlite.org/forum/forumpost/b1cc55671e
Context on gcc:
$ gcc --version
gcc (GCC) 14.1.1 20240620 (Red Hat 14.1.1-6)
$ rpm -qf /usr/bin/gcc
gcc-14.1.1-6.fc40.x86_64
$ lsb_release -a
LSB Version: :core-5.0-amd64:core-5.0-noarch
Distributor ID: Fedora
Description: Fedora release 40 (Forty)
$ uname -a
Linux test 6.9.5-200.fc40.x86_64 #1 SMP PREEMPT_DYNAMIC Sun Jun 16 15:47:09 UTC
2024 x86_64 GNU/Linux
Best,
Christian
