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* [Bug c++/55340] New: Invalid maybe unitialized warning @ 2012-11-15 12:51 jwillemsen at remedy dot nl 2012-11-15 14:17 ` [Bug c++/55340] " jwillemsen at remedy dot nl ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: jwillemsen at remedy dot nl @ 2012-11-15 12:51 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55340 Bug #: 55340 Summary: Invalid maybe unitialized warning Classification: Unclassified Product: gcc Version: 4.7.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: jwillemsen@remedy.nl Created attachment 28698 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28698 gzip with both preprocessed files We have in some of our tests a warning that a variable may be used unitialized, but we have validated that this is not the case (as far as we could tell). We tried to reduce our code to a minimum, but the strange thing is that when we remove some not related code, the warning is gone. Attached 2 preprocessed files, t.cpp t2.cpp, compile using: g++ --std=c++0x -fno-strict-aliasing -fvisibility=hidden -fvisibility-inlines-hidden -O3 -ggdb -m64 -pthread -Wall -W -Wpointer-arith -pipe -D_GNU_SOURCE -c t.cpp When compiling t.cpp we get: In file included from testC.cpp:26:0: testC.h: In member function ‘void Test::union_union::swap(Test::union_union&)’: testC.h:764:3: warning: ‘*((void*)(& intermediate)+8).Test::unionType::disc_’ may be used uninitialized in this function [-Wmaybe-uninitialized] testC.h:1325:27: note: ‘*((void*)(& intermediate)+8).Test::unionType::disc_’ was declared here When compiling t2.cpp there is no warning. If you check the diff between t.cpp and t2.cpp you will see that the code that triggers the warning is still there. We have reduced the code to the point that removal of any type would not trigger the warning. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/55340] Invalid maybe unitialized warning 2012-11-15 12:51 [Bug c++/55340] New: Invalid maybe unitialized warning jwillemsen at remedy dot nl @ 2012-11-15 14:17 ` jwillemsen at remedy dot nl 2013-02-27 16:04 ` paolo.carlini at oracle dot com 2013-02-27 19:20 ` jwillemsen at remedy dot nl 2 siblings, 0 replies; 4+ messages in thread From: jwillemsen at remedy dot nl @ 2012-11-15 14:17 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55340 --- Comment #1 from Johnny Willemsen <jwillemsen at remedy dot nl> 2012-11-15 14:17:38 UTC --- Lowering optimization from -O3 to -O2 removes the warning ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/55340] Invalid maybe unitialized warning 2012-11-15 12:51 [Bug c++/55340] New: Invalid maybe unitialized warning jwillemsen at remedy dot nl 2012-11-15 14:17 ` [Bug c++/55340] " jwillemsen at remedy dot nl @ 2013-02-27 16:04 ` paolo.carlini at oracle dot com 2013-02-27 19:20 ` jwillemsen at remedy dot nl 2 siblings, 0 replies; 4+ messages in thread From: paolo.carlini at oracle dot com @ 2013-02-27 16:04 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55340 Paolo Carlini <paolo.carlini at oracle dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution| |WORKSFORME --- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-02-27 16:03:22 UTC --- Mainline (would be 4.8.0) is fine and I can't even compile the testcase with 4_6-branch, thus this isn't a regression. In the future, please do your best to reduce the size of your testcase: in 99.999 % of the cases, 2-3 KB are enough. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/55340] Invalid maybe unitialized warning 2012-11-15 12:51 [Bug c++/55340] New: Invalid maybe unitialized warning jwillemsen at remedy dot nl 2012-11-15 14:17 ` [Bug c++/55340] " jwillemsen at remedy dot nl 2013-02-27 16:04 ` paolo.carlini at oracle dot com @ 2013-02-27 19:20 ` jwillemsen at remedy dot nl 2 siblings, 0 replies; 4+ messages in thread From: jwillemsen at remedy dot nl @ 2013-02-27 19:20 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55340 --- Comment #3 from Johnny Willemsen <jwillemsen at remedy dot nl> 2013-02-27 19:20:24 UTC --- Thanks for checking this, will also try 4.8.0 at some point. We have hundreds of tests using C++11 extensively and this was the only one exposing this warning. This is mostly generated code and I tried to reduce it further, but when I reduced it further the warning was gone. I didn't had a clue why it could be triggered, that lack of knowledge prevented me from reducing the test case further ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-02-27 19:20 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-11-15 12:51 [Bug c++/55340] New: Invalid maybe unitialized warning jwillemsen at remedy dot nl 2012-11-15 14:17 ` [Bug c++/55340] " jwillemsen at remedy dot nl 2013-02-27 16:04 ` paolo.carlini at oracle dot com 2013-02-27 19:20 ` jwillemsen at remedy dot nl
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