https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87489
Bug ID: 87489
Summary: Spurious -Wnonnull warning
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: andres at anarazel dot de
Target Milestone: ---
Created attachment 44775
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44775&action=edit
Repro
Hi,
With the attached, obviously heavily condensed, testcase I get a spurious
-Wnonnull warning. It's quite true that the argument to strlen is NULL, but
the code isn't reachable if so. As the warning isn't phrased as "may be",
that doesn't seem quite right.
$ gcc-8 -Wnonnull -O2 -c xact.stripped.i
In function ‘XactLogCommitRecord.constprop’,
inlined from ‘RecordTransactionCommit’ at xact.stripped.i:51:3:
xact.stripped.i:44:50: warning: argument 1 null where non-null expected
[-Wnonnull]
XLogRegisterData((const char *) twophase_gid, strlen(twophase_gid) + 1);
^~~~~~~~~~~~~~~~~~~~
xact.stripped.i: In function ‘RecordTransactionCommit’:
xact.stripped.i:19:15: note: in a call to function ‘strlen’ declared here
extern size_t strlen (const char *__s)
^~~~~~
While the concrete problem in postgres only triggers for gcc-8 at -O3, the
simplified testcase triggers for 7, 8, and a recent-ish trunk, and even with
-O1.
Without the first XLogRegisterData() call the warning does not appear.
- Andres
