https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109611
Bug ID: 109611
Summary: Missing -Wrestrict across TUs (even with LTO)
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
CC: arsen at gcc dot gnu.org
Blocks: 84774
Target Milestone: ---
```
$ cat test.c
#include <string.h>
char foo[200];
char* bar(char*);
int main (int argc, char **argv) {
strncpy (foo, bar (foo) + 50, 70);
}
$ cat test2.c
char* bar (char* x) {
return x;
}
```
```
$ gcc -flto-partition=none -flto test2.c test.c -Wrestrict -O3
[no -Wrestrict warning]
```
But by forcing them all into the same TU:
```
$ cat test{2,}.c | gcc -x c - -O3 -Wrestrict -S -o /dev/null
In file included from /usr/include/string.h:535,
from <stdin>:6:
In function ‘strncpy’,
inlined from ‘main’ at <stdin>:14:3:
/usr/include/bits/string_fortified.h:95:10: warning: ‘__builtin_strncpy’
accessing 70 bytes at offsets 0 and 50 overlaps between 1 and 20 bytes at
offset 50 [-Wrestrict]
[...]
```
None of -fwhole-program, -flto-partition=none nor -flto-partition=one make any
difference.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84774
[Bug 84774] [meta-bug] bogus/missing -Wrestrict
