https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100442
Bug ID: 100442
Summary: Spurious -Wstringop-overread error with odd boundaries
Product: gcc
Version: 11.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: andres at anarazel dot de
Target Milestone: ---
Hi,
When compiling one of postgres' source files with -O3 I see the following:
gcc-11 -O3 -Wall -o /dev/null -c tsvector_op.i
In function 'tsCompareString',
inlined from 'tsCompareString' at
/home/andres/src/postgresql/src/backend/utils/adt/tsvector_op.c:1147:1,
inlined from 'tsvector_bsearch' at
/home/andres/src/postgresql/src/backend/utils/adt/tsvector_op.c:410:9:
/home/andres/src/postgresql/src/backend/utils/adt/tsvector_op.c:1164:23:
warning: 'memcmp' specified bound [18446744073709551612, 18446744073709551615]
exceeds maximum object size 9223372036854775807 [-Wstringop-overread]
1164 | cmp = memcmp(a, b, Min(lena, lenb));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
which does not seem plausible ;). As far as I can tell the values actually
passed to memcmp are reasonable.
I've attached both the preprocessed source file. I tried to reduce it using
creduce - but it hung and reported a bug (which I did, an hour ago).
andres@awork3:~/src/postgresql$ gcc-11 --version
gcc-11 (Debian 11.1.0-1) 11.1.0
This also happens with gcc-10 (except reported as -Wstringop-overflow=), but
not 9.
Regards,
Andres
