[Bug optimization/13653] [3.3 regression] -O2 -funroll-loop miscompiles POOMA testcase

[rguenth at tat dot physik dot uni-tuebingen dot de]

------- Additional Comments From rguenth at tat dot physik dot uni-tuebingen dot de  2004-01-14 21:22 -------
Debian g++ (GCC) 3.3.3 20040110 (prerelease) (Debian) on powerpc-linux(!)
doesn't show the problem.  Also maybe this is a libstdc++ bug, so there is an
"unincluded" version of the testcase at

http://www.tat.physik.uni-tuebingen.de/~rguenth/gcc/array_test1.cpp.gz

I checked the gdb backtrace of the SIGSEGV and it segfaults during output
to a stream in malloc'ing a ridiculous amount of memory (1076086304 bytes)
coming from std::__default_alloc_template<true, 0>::allocate(unsigned)
coming from std::string::_Rep::_S_create() and so on.  So it looks like   
either a builtin failure (folding some strlen of a constant string comes  
to my mind) or a (long standing) loop optimizer bug triggered by a change
to libstdc++ strings or related area.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13653