[Valgrind-users] gcc -O2 problem SSE optimization?

[Kevyn-Alexandre P. <ka...@ro...>]

Hi,

Here the problem that I have with valgrind-3.6.1-Debian (Ubuntu 11.10), valgrind-3.7.0 (Ubuntu 12.04) and on SVN version:

gcc -o test MallocProblemO2.cxx
valgrind --leak-check=full ./test

No problem

If I add the -O2 flag it result in a Invalid read of 4 bytes:

gcc -O2 -o test MallocProblemO2.cxx
valgrind --leak-check=full ./test

==21719== Memcheck, a memory error detector
==21719== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==21719== Using Valgrind-3.6.1-Debian and LibVEX; rerun with -h for copyright info
==21719== Command: ./test
==21719== 
==21719== Invalid read of size 4
==21719==    at 0x4004F0: main (in /home/kapare/Documents/test)
==21719==  Address 0x51d0044 is 4 bytes inside a block of size 6 alloc'd
==21719==    at 0x4C279F2: calloc (vg_replace_malloc.c:467)
==21719==    by 0x4004DF: main (in /home/kapare/Documents/test)
==21719== 
EXPECT STRLENGTH OF 4: 4
EXPECT STR "0123": 0123
==21719== 
==21719== HEAP SUMMARY:
==21719==     in use at exit: 0 bytes in 0 blocks
==21719==   total heap usage: 1 allocs, 1 frees, 6 bytes allocated
==21719== 
==21719== All heap blocks were freed -- no leaks are possible
==21719== 
==21719== For counts of detected and suppressed errors, rerun with: -v
==21719== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 4 from 4)


This problem seem to be the same as this old one:
https://bugzilla.redhat.com/show_bug.cgi?id=518247


I have enter a bug for the issue 301922