Bug#144232: g++-3.0: exception handling doesn't work with -O flags

[Zdenek Kabelac <kabi@informatics.muni.cz>]

Package: g++-3.0
Version: 1:3.0.4-7
Severity: normal

Hello

I'm adding my sample program which demonstrate that  C++
program is unusable with -O2 (or better compilation)
moreover it seems to be also affected by march=i5/686 flag

check out 524000 iteration 

you may lower the char array a[10] - in that case it will
pass the test with -O2 & stack-check

It looks like the bug is in all gcc compilers I could check
(and it's very annoying for me as avifile developer - basicaly
I've to compile avifile C++ part without any -O2 flags otherwice
unexpected mystery abort are appearing becuase of uncatched exception)

(Do I have to repost this bug for 2.95 as well - though in that
case even lowering a[a] doesn't help - only -fno-deferer-pop
but still I do get craches with march option



/*
 * rm test; CXXFLAGS=" -g -O2" make test
 * - note the major speedup when throw(exception) isn't specified
 * - with -O2 it will crash after 524000 iterations
 *
 * the minimum problematic option is: -fdefer-pop
 * to immediately hit the bug use: -fstack-check
 *
 * bug is visible with all GCC compilers I know
 */
#include <cstdio>

struct myexcept { char a[10000]; };
class testcl { public: testcl() { throw myexcept(); } };

int main(int argc, char** argv)
{
    volatile unsigned char a[128];
    //for (int i = 0; i < sizeof(a); i++) a[i] = i & 0xff;

    for (int i = 0; ; i++)
    {
        testcl* c = 0;
        //for (int j = sizeof(a) - 1; j > sizeof(a) - 32;  j--) printf("%3d .. %3d\n", j, a[j]);
        try { c = new testcl(); }
        catch (...) { if ((i % 1000) == 0)  printf("%d : %p\n", i, c); }
        delete c;
    }
}

-- System Information
Debian Release: 3.0
Architecture: i386
Kernel: Linux dual 2.4.19-pre6 #3 SMP Po dub 8 21:37:32 CEST 2002 i686
Locale: LANG=cs_CZ, LC_CTYPE=cs_CZ

Versions of packages g++-3.0 depends on:
ii  gcc-3.0                       1:3.0.4-7  The GNU C compiler.
ii  gcc-3.0-base                  1:3.0.4-7  The GNU Compiler Collection (base 
ii  libc6                         2.2.5-4    GNU C Library: Shared libraries an
ii  libstdc++3-dev                1:3.0.4-7  The GNU stdc++ library version 3 (



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