https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121044
Bug ID: 121044
Summary: False positive -Warray-bounds iwith GCC 14 and NEON
intrinsics
Product: gcc
Version: 14.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: jpalus+gcc at fastmail dot com
Target Milestone: ---
Created attachment 61846
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=61846&action=edit
reproducer
Based on mbedtls build failure (upstream report
https://github.com/Mbed-TLS/mbedtls/issues/9003) attached reproducer for false
positive -Warray-bounds when targeting aarch64:
$ gcc -O2 -Warray-bounds repro.c -c -o repro.o
In function ‘xor’,
inlined from ‘foo’ at repro.c:27:5:
repro.c:19:17: warning: array subscript 48 is outside array bounds of ‘unsigned
char[48]’ [-Warray-bounds=]
19 | r[i] = a[i] ^ b[i];
| ~^~~
repro.c: In function ‘foo’:
repro.c:25:19: note: at offset 48 into object ‘tmp’ of size 48
25 | unsigned char tmp[48] = { 0 };
| ^~~
In function ‘xor’,
inlined from ‘foo’ at repro.c:27:5:
repro.c:19:14: warning: array subscript 48 is outside array bounds of ‘unsigned
char[48]’ [-Warray-bounds=]
19 | r[i] = a[i] ^ b[i];
| ~~~~~^~~~~~~~~~~~~
repro.c: In function ‘foo’:
repro.c:25:19: note: at offset 48 into object ‘tmp’ of size 48
25 | unsigned char tmp[48] = { 0 };
| ^~~
Note that it appears to affect GCC 14.x only (13.x/15.x seem to work fine
according to godbolt).
