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From: "joona.kiiski at iki dot fi" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/64491] warning: loop exit may only be reached after undefined behavior Date: Sat, 10 Jan 2015 15:58:00 -0000 [thread overview] Message-ID: <bug-64491-4-Ss5JNfhWzm@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-64491-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64491 joona.kiiski at iki dot fi changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |joona.kiiski at iki dot fi --- Comment #2 from joona.kiiski at iki dot fi --- Hi, My name is Joona Kiiski, I'm one the authors of Stockfish chess software (https://stockfishchess.org/). This bug was originally reported to us a week ago. After initial analysis it looked obviously like a gcc bug, so we advised the reporter to raise a bug against GCC. Unfortunately, he wasn't able to give you nearly enough details. I hope that what I can provide below meets your expectations: - Environment: qemu-x86-64 running debian sid - GCC: Debian snapshot 20141812 5.0 - The bug appears when compiling the Stockfish master branch from https://github.com/official-stockfish/Stockfish.git with this snapshot. - For you convenience I've reduced the problem to: <test.cpp> int A[8]; int B[8]; int C; int main() { for (int f = 0; f <= 7; ++f) A[f] = f; for (int f = 0; f <= 7; ++f) B[f] = (f > 0 ? A[f - 1] : 0) | (f < 7 ? A[f + 1] : 0); C = B[7]; } </test.cpp> Compile with <Makefile> CXXFLAGS += -O3 -flto LDFLAGS += $(CXXFLAGS) test: test.o $(CXX) -o $@ test.o $(LDFLAGS) </Makefile> Files above are also viewable at https://github.com/official-stockfish/Stockfis/tree/gcc_bug/src This produces the bogus warning mentioned in the original bug report. If you need any further details, please let me know. Kind Regards, Joona Kiiski
next prev parent reply other threads:[~2015-01-10 15:58 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-01-04 20:24 [Bug c++/64491] New: " stuwph at live dot de 2015-01-04 20:46 ` [Bug c++/64491] " redi at gcc dot gnu.org 2015-01-10 15:58 ` joona.kiiski at iki dot fi [this message] 2015-01-10 16:04 ` joona.kiiski at iki dot fi 2015-01-10 16:49 ` [Bug c++/64491] [5 Regression] incorrect " Joost.VandeVondele at mat dot ethz.ch 2015-01-11 22:10 ` [Bug middle-end/64491] " joona.kiiski at gmail dot com 2015-01-12 7:18 ` Joost.VandeVondele at mat dot ethz.ch 2015-02-09 0:06 ` pinskia at gcc dot gnu.org 2015-02-18 13:57 ` jakub at gcc dot gnu.org 2015-02-18 16:25 ` ams at gcc dot gnu.org 2015-02-18 16:28 ` jakub at gcc dot gnu.org 2015-02-20 11:28 ` ams at gcc dot gnu.org 2015-02-24 17:01 ` ams at gcc dot gnu.org 2015-02-24 19:18 ` jakub at gcc dot gnu.org 2015-03-18 12:50 ` rguenth at gcc dot gnu.org 2015-03-18 12:53 ` jakub at gcc dot gnu.org 2015-03-18 14:27 ` ams at gcc dot gnu.org 2015-03-18 14:29 ` ams at gcc dot gnu.org
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