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[Bug optimization/13411] New: segmentation fault occurs in correct code - optimisation problem at O2
- From: "micis at gmx dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 16 Dec 2003 16:01:41 -0000
- Subject: [Bug optimization/13411] New: segmentation fault occurs in correct code - optimisation problem at O2
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
A small function named SM33S destroys local variables which lead to an
segmentation fault when called twice.
This error occurs only when some printf statements are after the declaration
of variables and not at the beginning of the function.
Also the function works when the adresses of data accesses are checked.
It seems to be an optimisation problem since it occurs only at -O2 or higher.
At -O0 the compiler generates an internal compiler error, but I will submit
this in a different bug report.
This program is a test program for developing an altivec function. The
same operation is implemented in different ways (with and without altivec
code) and the results are compared.
If the altivec implementation is removed or returns immediately, SM33S
alters one of the loacal variables in main() but no segmentation error
occurs.
I have tried to narrow this bug down, but if you change to much on that
program, the error will not occur.
output from gcc -v:
Reading specs from /usr/lib/gcc-lib/powerpc-linux/3.3.2/specs
Configured with: ../src/configure -v
--enable-languages=c,c++,java,f77,pascal,objc,ada --prefix=/usr
--mandir=/usr/share/man --infodir=/usr/share/info
--with-gxx-include-dir=/usr/include/c++/3.3 --enable-shared
--with-system-zlib --enable-nls --without-included-gettext
--enable-__cxa_atexit --enable-clocale=gnu --enable-java-gc=boehm
--enable-java-awt=xlib --enable-objc-gc --disable-multilib powerpc-linux
Thread model: posix
gcc version 3.3.2 (Debian)
gcc command line:
gcc -g -o matbug matbug.cpp -mcpu=7450 -maltivec -O2 -lstdc++ -Wall -pedantic -
lefence -save-temps -fverbose-asm
--
Summary: segmentation fault occurs in correct code - optimisation
problem at O2
Product: gcc
Version: 3.3.2
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: micis at gmx dot de
CC: gcc-bugs at gcc dot gnu dot org
GCC host triplet: powerpc-linux
GCC target triplet: powerpc-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13411