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[Bug lto/84212] -Wno-* does not disable warnings from -flto link stage
- From: "msebor at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 05 Feb 2018 15:55:29 +0000
- Subject: [Bug lto/84212] -Wno-* does not disable warnings from -flto link stage
- Auto-submitted: auto-generated
- References: <bug-84212-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84212
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic
Status|UNCONFIRMED |NEW
Last reconfirmed| |2018-02-05
CC| |msebor at gcc dot gnu.org
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=71907,
| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=78768,
| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=79062
Ever confirmed|0 |1
Known to fail| |7.3.0, 8.0
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Confirmed with both 7.x where -Wstringop-overflow was first introduced and with
8.0, so it's not a regression. (A false positive would be, independent of this
bug, if a test case is provided that reproduces it.)
Prior to the introduction of -Wstringop-overflow GCC would print the same
warning (minus the sizes) but with no option to suppress it.
$ (gcc -D_FORTIFY_SOURCE=2 -O3 -flto'; $gcc -c a.c b.c && gcc a.o b.o)
In function ‘memset’,
inlined from ‘main’ at a.c:4:2:
/usr/include/bits/string3.h:90:10: warning: call to __builtin___memset_chk will
always overflow destination buffer
return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest));
^
See also pr71907, pr78768, and pr79062, for other problems with the
interaction of -flto and some of these middle-end options.