From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31196 invoked by alias); 8 Feb 2008 15:05:51 -0000 Received: (qmail 31084 invoked by uid 48); 8 Feb 2008 15:05:07 -0000 Date: Fri, 08 Feb 2008 15:05:00 -0000 Subject: [Bug c++/35140] New: floating point error in combination with std::list with -O2 optimization turned on X-Bugzilla-Reason: CC Message-ID: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "basti at fkp dot tu-darmstadt dot de" 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 X-SW-Source: 2008-02/txt/msg00956.txt.bz2 The following program: //------------------------------------ #include #include class sample { public: double criterium; sample(double _criterium):criterium(_criterium) {}; }; int main(){ std::list samples; samples.push_back(sample(1.)); double tmp=0.; std::list::iterator i1; i1=samples.begin(); tmp=(*i1).criterium; // !!!!!!!!!!!!!!!!!!!!! // THIS += operation fails (*i1).criterium+=2.; //!!!!!!!!!!!!!!!!!!!!!!!! std::cout<<"tmp "< search starts here: /usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../include/c++/4.1.2 /usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../include/c++/4.1.2/i486-linux-gnu /usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../include/c++/4.1.2/backward /usr/local/include /usr/lib/gcc/i486-linux-gnu/4.1.2/include /usr/include End of search list. /usr/lib/gcc/i486-linux-gnu/4.1.2/cc1plus -fpreprocessed tst_short.ii -quiet -dumpbase tst_short.cpp -mtune=i686 -auxbase tst_short -g -O2 -version -o tst_short.s GNU C++ version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21) (i486-linux-gnu) compiled by GNU C version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21). GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129483 Compiler executable checksum: 183d42a838ed2b7313bffcb8f2f2fda7 as -V -Qy -o tst_short.o tst_short.s GNU assembler version 2.17 (i486-linux-gnu) using BFD version 2.17 Debian GNU/Linux /usr/lib/gcc/i486-linux-gnu/4.1.2/collect2 --eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -o tst_short_O2 /usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../lib/crt1.o /usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../lib/crti.o /usr/lib/gcc/i486-linux-gnu/4.1.2/crtbegin.o -L/usr/lib/gcc/i486-linux-gnu/4.1.2 -L/usr/lib/gcc/i486-linux-gnu/4.1.2 -L/usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../lib -L/lib/../lib -L/usr/lib/../lib tst_short.o -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/i486-linux-gnu/4.1.2/crtend.o /usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../lib/crtn.o ================================================ System 2: Using built-in specs. Target: i486-linux-gnu Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.1.3 --program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --enable-checking=release i486-linux-gnu Thread model: posix gcc version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2) /usr/lib/gcc/i486-linux-gnu/4.1.3/cc1plus -E -quiet -v -D_GNU_SOURCE tst_short.cpp -mtune=generic -fpch-preprocess -o tst_short.ii ignoring nonexistent directory "/usr/local/include/i486-linux-gnu" ignoring nonexistent directory "/usr/lib/gcc/i486-linux-gnu/4.1.3/../../../../i486-linux-gnu/include" ignoring nonexistent directory "/usr/include/i486-linux-gnu" #include "..." search starts here: #include <...> search starts here: /usr/include/c++/4.1.3 /usr/include/c++/4.1.3/i486-linux-gnu /usr/include/c++/4.1.3/backward /usr/local/include /usr/lib/gcc/i486-linux-gnu/4.1.3/include /usr/include End of search list. /usr/lib/gcc/i486-linux-gnu/4.1.3/cc1plus -fpreprocessed tst_short.ii -quiet -dumpbase tst_short.cpp -mtune=generic -auxbase tst_short -version -fstack-protector -fstack-protector -o tst_short.s GNU C++ version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2) (i486-linux-gnu) compiled by GNU C version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2). GGC heuristics: --param ggc-min-expand=64 --param ggc-min-heapsize=64316 Compiler executable checksum: 3cc47be363985179cfafdceddd0e8f5d as --traditional-format -V -Qy -o tst_short.o tst_short.s GNU assembler version 2.18 (i486-linux-gnu) using BFD version (GNU Binutils for Ubuntu) 2.18 /usr/lib/gcc/i486-linux-gnu/4.1.3/collect2 --eh-frame-hdr -m elf_i386 --hash-style=both -dynamic-linker /lib/ld-linux.so.2 -o tst_short /usr/lib/gcc/i486-linux-gnu/4.1.3/../../../../lib/crt1.o /usr/lib/gcc/i486-linux-gnu/4.1.3/../../../../lib/crti.o /usr/lib/gcc/i486-linux-gnu/4.1.3/crtbegin.o -L/usr/lib/gcc/i486-linux-gnu/4.1.3 -L/usr/lib/gcc/i486-linux-gnu/4.1.3 -L/usr/lib/gcc/i486-linux-gnu/4.1.3/../../../../lib -L/lib/../lib -L/usr/lib/../lib tst_short.o -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/i486-linux-gnu/4.1.3/crtend.o /usr/lib/gcc/i486-linux-gnu/4.1.3/../../../../lib/crtn.o -- Summary: floating point error in combination with std::list with -O2 optimization turned on Product: gcc Version: 4.1.3 Status: UNCONFIRMED Severity: major Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: basti at fkp dot tu-darmstadt dot de http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35140