On 19 January 2011 21:14, Máté Soós wrote: > Dear All, > > I maintain a program and I seemed to have stumbled into some bug of > either the program or gcc. Thanks to Vegard Nossum, we have a really > small (101 lines, most of them empty) example to reproduce it. It'd be under 100 lines without the unnecessary extern "C" block ;-) > The bug > appears when I compile the program with gcc 4.5.1 (I believe it > appears for 4.5.0 and 4.5.2 as well), with -O2. The program is meant > to print "success", but when compiled with -O2 it returns "failure", > while for -O0 works fine. The file is available here: > > http://planete.inrialpes.fr/~soos/gcc/ > > as "Main.cpp" and "compile.sh". > > Machine it is compiled on: > distribution: Fedora Core 14 > gcc --version: gcc (GCC) 4.5.1 20100924 (Red Hat 4.5.1-4) > uname -a: Linux localhost.localdomain 2.6.35.6-45.fc14.i686 #1 SMP Mon > Oct 18 23:56:17 UTC 2010 i686 i686 i386 GNU/Linux > > This bug seemed to have been triggered in the original (>13'000 LOC) > program by multiple people, using multiple 4.5.X versions, on > different computers&distributions. > > Does anyone know why I get this bug? Could anyone confirm that this > the bug triggers on their architecture, distribution, and compiler > version (only >= 4.5.0 seems to be affected)? FWIW, 4.6.0 prints "success" but I do get "error" with GCC 4.5.3 at -O2 or -O3, on x86_64 Fedora 13
