When using a volatile function pointer and compiling with -O2 optimization, the
resulting program will not correctly return from the function pointer but will
instead jump to another point of the program. I have been able to reproduce
this behavior with gcc 3.4.6, 4.0.2 and the x86 locally hosted 4.1.1 version of
gcc.
Originally the bug was discovered with:
$ powerpc-603-linux-gnu-gcc -v
Reading specs from
/opt/crosstool/gcc-3.4.5-glibc-2.3.6/powerpc-603-linux-gnu/lib/gcc/powerpc-603-linux-gnu/3.4.5/specs
Configured with:
/home/mbenedict/src/crosstool-0.43/build/powerpc-603-linux-gnu/gcc-3.4.5-glibc-2.3.6/gcc-3.4.5/configure
--target=powerpc-603-linux-gnu --host=i686-host_pc-linux-gnu
--prefix=/opt/crosstool/gcc-3.4.5-glibc-2.3.6/powerpc-603-linux-gnu
--with-cpu=603 --enable-cxx-flags=-mcpu=603
--with-headers=/opt/crosstool/gcc-3.4.5-glibc-2.3.6/powerpc-603-linux-gnu/powerpc-603-linux-gnu/include
--with-local-prefix=/opt/crosstool/gcc-3.4.5-glibc-2.3.6/powerpc-603-linux-gnu/powerpc-603-linux-gnu
--disable-nls --enable-threads=posix --enable-symvers=gnu --enable-__cxa_atexit
--enable-languages=c --enable-shared --enable-c99 --enable-long-long
Thread model: posix
gcc version 3.4.5
I will attach the .i file that reproduces this condition in the first comment
(I can't seem to attach from the new bug screen).
--
Summary: Optimization corrupts volatile function pointer return
handling
Product: gcc
Version: 3.4.5
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: mbenedict at aclaratech dot com
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: powerpc-603-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36226
