public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c++/105646] New: g++ does not raise xxx is used uninitialized warning under some conditions
@ 2022-05-18 14:07 cfy1990 at gmail dot com
2022-05-18 14:13 ` [Bug c++/105646] " cfy1990 at gmail dot com
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: cfy1990 at gmail dot com @ 2022-05-18 14:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105646
Bug ID: 105646
Summary: g++ does not raise xxx is used uninitialized warning
under some conditions
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: cfy1990 at gmail dot com
Target Milestone: ---
g++ version: g++ (Compiler-Explorer-Build-gcc--binutils-2.38) 12.1.0
Code link: https://godbolt.org/z/5MansKa5c
Compile arguments: -std=c++11 -Wextra -Wall -O2
Code:
int f1();
int f2(){
bool v2{v2}; // used uninitialized warning
auto const & a = f1();
return a;
}
int f3(){
auto const & a = f1();
bool v3{v3}; // no warning in g++, got uninitialized warning in clang
return a;
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/105646] g++ does not raise xxx is used uninitialized warning under some conditions
2022-05-18 14:07 [Bug c++/105646] New: g++ does not raise xxx is used uninitialized warning under some conditions cfy1990 at gmail dot com
@ 2022-05-18 14:13 ` cfy1990 at gmail dot com
2022-09-29 8:24 ` [Bug tree-optimization/105646] g++ does not raise "xxx may be used uninitialized" warning on dead code when optimizing cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: cfy1990 at gmail dot com @ 2022-05-18 14:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105646
--- Comment #1 from cfy1990 at gmail dot com ---
When compile without -O2, g++ will generate "'v3' may be used uninitialized"
warning.
code link: https://godbolt.org/z/r3sY4srx9
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/105646] g++ does not raise "xxx may be used uninitialized" warning on dead code when optimizing
2022-05-18 14:07 [Bug c++/105646] New: g++ does not raise xxx is used uninitialized warning under some conditions cfy1990 at gmail dot com
2022-05-18 14:13 ` [Bug c++/105646] " cfy1990 at gmail dot com
@ 2022-09-29 8:24 ` cvs-commit at gcc dot gnu.org
2022-09-29 8:24 ` rguenth at gcc dot gnu.org
2022-10-27 0:54 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-09-29 8:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105646
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:
https://gcc.gnu.org/g:a1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d
commit r13-2926-ga1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d
Author: Richard Biener <rguenther@suse.de>
Date: Fri Aug 19 15:11:14 2022 +0200
tree-optimization/105646 - re-interpret always executed in uninit diag
The following fixes PR105646, not diagnosing
int f1();
int f3(){
auto const & a = f1();
bool v3{v3};
return a;
}
with optimization because the early uninit diagnostic pass only
diagnoses always executed cases. The patch does this by
re-interpreting what always executed means and choosing to
ignore exceptional and abnormal control flow for this. At the
same time it improves things as suggested in a comment - when
the value-numbering run done without optimizing figures there's
a fallthru path, consider blocks on it as always executed.
PR tree-optimization/105646
* tree-ssa-uninit.cc (warn_uninitialized_vars): Pre-compute
the set of fallthru reachable blocks from function entry
and use that to determine wlims.always_executed.
* g++.dg/uninit-pr105646.C: New testcase.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/105646] g++ does not raise "xxx may be used uninitialized" warning on dead code when optimizing
2022-05-18 14:07 [Bug c++/105646] New: g++ does not raise xxx is used uninitialized warning under some conditions cfy1990 at gmail dot com
2022-05-18 14:13 ` [Bug c++/105646] " cfy1990 at gmail dot com
2022-09-29 8:24 ` [Bug tree-optimization/105646] g++ does not raise "xxx may be used uninitialized" warning on dead code when optimizing cvs-commit at gcc dot gnu.org
@ 2022-09-29 8:24 ` rguenth at gcc dot gnu.org
2022-10-27 0:54 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-09-29 8:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105646
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Known to work| |13.0
Resolution|--- |FIXED
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/105646] g++ does not raise "xxx may be used uninitialized" warning on dead code when optimizing
2022-05-18 14:07 [Bug c++/105646] New: g++ does not raise xxx is used uninitialized warning under some conditions cfy1990 at gmail dot com
` (2 preceding siblings ...)
2022-09-29 8:24 ` rguenth at gcc dot gnu.org
@ 2022-10-27 0:54 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-10-27 0:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105646
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |13.0
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-10-27 0:54 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-18 14:07 [Bug c++/105646] New: g++ does not raise xxx is used uninitialized warning under some conditions cfy1990 at gmail dot com
2022-05-18 14:13 ` [Bug c++/105646] " cfy1990 at gmail dot com
2022-09-29 8:24 ` [Bug tree-optimization/105646] g++ does not raise "xxx may be used uninitialized" warning on dead code when optimizing cvs-commit at gcc dot gnu.org
2022-09-29 8:24 ` rguenth at gcc dot gnu.org
2022-10-27 0:54 ` pinskia at gcc dot gnu.org
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).