From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5388 invoked by alias); 17 Jun 2014 07:05:22 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 5340 invoked by uid 48); 17 Jun 2014 07:05:15 -0000 From: "Ulrich.Windl at rz dot uni-regensburg.de" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/61531] New: Optimizer completely removes some bitset code Date: Tue, 17 Jun 2014 07:05:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: 4.3.4 X-Bugzilla-Keywords: X-Bugzilla-Severity: major X-Bugzilla-Who: Ulrich.Windl at rz dot uni-regensburg.de X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-06/txt/msg01415.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D61531 Bug ID: 61531 Summary: Optimizer completely removes some bitset code Product: gcc Version: 4.3.4 Status: UNCONFIRMED Severity: major Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: Ulrich.Windl at rz dot uni-regensburg.de I wrote a simple test code for that the default optimization compl= ete removes. Only -O0 keept the code. However the default code should output. T= hus I consider the optimization bad. Preprocessed input will follow, but here is the basic test: --- ~/src/C++/bitsettest> cat bstest.cc #include #include int main(int argc, char *argv[]) { std::bitset<32> b; #if 0 std::cout << "size " << b.size() << std::endl; #endif b.set(2); if (b.test(2)) std::cout << "set 2" << std::endl; if (b[3]) std::cout << "set 3" << std::endl; return 0; } ~/src/C++/bitsettest> make g++ -Wall -Wextra -Wshadow -pipe -O2 -g --save-temps -c -o bstest.o bstest.cc g++: warning: -pipe ignored because -save-temps specified bstest.cc:4: warning: unused parameter =E2=80=98argc=E2=80=99 bstest.cc:4: warning: unused parameter =E2=80=98argv=E2=80=99 g++ -o bstest bstest.o ~/src/C++/bitsettest> (gdb) disassemble /m main Dump of assembler code for function main(int, char**): 4 int main(int argc, char *argv[]) 0x00000000004008b0 <+0>: sub $0x8,%rsp 5 { 6 std::bitset<32> b; 7 8 #if 0 9 std::cout << "size " << b.size() << std::endl; 10 #endif 11 b.set(2); 12 if (b.test(2)) 13 std::cout << "set 2" << std::endl; 14 if (b[3]) 15 std::cout << "set 3" << std::endl; 16 return 0; 17 } 0x00000000004008d2 <+34>: xor %eax,%eax 0x00000000004008d4 <+36>: add $0x8,%rsp 0x00000000004008d8 <+40>: retq End of assembler dump. --- >>From gcc-bugs-return-454334-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Jun 17 07:11:26 2014 Return-Path: Delivered-To: listarch-gcc-bugs@gcc.gnu.org Received: (qmail 9822 invoked by alias); 17 Jun 2014 07:11:26 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Delivered-To: mailing list gcc-bugs@gcc.gnu.org Received: (qmail 9803 invoked by uid 48); 17 Jun 2014 07:11:21 -0000 From: "Ulrich.Windl at rz dot uni-regensburg.de" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/61531] Optimizer completely removes some bitset code Date: Tue, 17 Jun 2014 07:11:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: 4.3.4 X-Bugzilla-Keywords: X-Bugzilla-Severity: major X-Bugzilla-Who: Ulrich.Windl at rz dot uni-regensburg.de X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-06/txt/msg01416.txt.bz2 Content-length: 209 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61531 --- Comment #1 from Ulrich Windl --- Exact version of g++ is that of SLES11 SP3 for x86_64 (gcc-c++-4.3-62.198).