[Bug c/40216] New: Optimization error when compiling bfd/ecofflink.c on x86_64
ch starts here: #include <...> search starts here: . ../../binutils-2.15.94.0.2.2/bfd ../../binutils-2.15.94.0.2.2/include ../../binutils-2.15.94.0.2.2/intl ../intl /usr/local/include /usr/lib/gcc/x86_64-redhat-linux/4.3.0/include /usr/include End of search list. COMPILER_PATH=/usr/libexec/gcc/x86_64-redhat-linux/4.3.0/:/usr/libexec/gcc/x86_64-redhat-linux/4.3.0/:/usr/libexec/gcc/x86_64-redhat-linux/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/:/usr/libexec/gcc/x86_64-redhat-linux/4.3.0/:/usr/libexec/gcc/x86_64-redhat-linux/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/ LIBRARY_PATH=/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../lib64/:/lib/../lib64/:/usr/lib/../lib64/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-v' '-save-temps' '-DHAVE_CONFIG_H' '-I.' '-I../../binutils-2.15.94.0.2.2/bfd' '-I.' '-D_GNU_SOURCE' '-I../../binutils-2.15.94.0.2.2/include' '-I../../binutils-2.15.94.0.2.2/intl' '-I../intl' '-W' '-Wall' '-Wstrict-prototypes' '-Wmissing-prototypes' '-g' '-O2' '-c' '-E' '-mtune=generic' Using built-in specs. Target: x86_64-redhat-linux Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --enable-plugin --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-cpu=generic --build=x86_64-redhat-linux Thread model: posix gcc version 4.3.0 20080428 (Red Hat 4.3.0-8) (GCC) COLLECT_GCC_OPTIONS='-v' '-save-temps' '-DHAVE_CONFIG_H' '-I.' '-I../../binutils-2.15.94.0.2.2/bfd' '-I.' '-D_GNU_SOURCE' '-I../../binutils-2.15.94.0.2.2/include' '-I../../binutils-2.15.94.0.2.2/intl' '-I../intl' '-W' '-Wall' '-Wstrict-prototypes' '-Wmissing-prototypes' '-g' '-O2' '-c' '-o' '/users/hblurfrushan/.ccache/tmp.hash.els-d60685.13738.o' '-mtune=generic' /usr/libexec/gcc/x86_64-redhat-linux/4.3.0/cc1 -fpreprocessed /users/hblurfrushan/.ccache/ecofflink.tmp.els-d60685.13738.i -quiet -dumpbase ecofflink.tmp.els-d60685.13738.i -mtune=generic -auxbase-strip /users/hblurfrushan/.ccache/tmp.hash.els-d60685.13738.o -g -O2 -W -Wall -Wstrict-prototypes -Wmissing-prototypes -version -o ecofflink.tmp.els-d60685.13738.s GNU C (GCC) version 4.3.0 20080428 (Red Hat 4.3.0-8) (x86_64-redhat-linux) compiled by GNU C version 4.3.0 20080428 (Red Hat 4.3.0-8), GMP version 4.2.2, MPFR version 2.3.0-p2. warning: MPFR header version 2.3.0-p2 differs from library version 2.3.1. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: 5ba4849f47331d70d30074ce61c70f61 COLLECT_GCC_OPTIONS='-v' '-save-temps' '-DHAVE_CONFIG_H' '-I.' '-I../../binutils-2.15.94.0.2.2/bfd' '-I.' '-D_GNU_SOURCE' '-I../../binutils-2.15.94.0.2.2/include' '-I../../binutils-2.15.94.0.2.2/intl' '-I../intl' '-W' '-Wall' '-Wstrict-prototypes' '-Wmissing-prototypes' '-g' '-O2' '-c' '-o' '/users/hblurfrushan/.ccache/tmp.hash.els-d60685.13738.o' '-mtune=generic' as -V -Qy -o /users/hblurfrushan/.ccache/tmp.hash.els-d60685.13738.o ecofflink.tmp.els-d60685.13738.s GNU assembler version 2.18.50.0.6 (x86_64-redhat-linux) using BFD version version 2.18.50.0.6-7.fc9 20080403 COMPILER_PATH=/usr/libexec/gcc/x86_64-redhat-linux/4.3.0/:/usr/libexec/gcc/x86_64-redhat-linux/4.3.0/:/usr/libexec/gcc/x86_64-redhat-linux/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/:/usr/libexec/gcc/x86_64-redhat-linux/4.3.0/:/usr/libexec/gcc/x86_64-redhat-linux/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/ LIBRARY_PATH=/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../lib64/:/lib/../lib64/:/usr/lib/../lib64/:/usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-v' '-save-temps' '-DHAVE_CONFIG_H' '-I.' '-I../../binutils-2.15.94.0.2.2/bfd' '-I.' '-D_GNU_SOURCE' '-I../../binutils-2.15.94.0.2.2/include' '-I../../binutils-2.15.94.0.2.2/intl' '-I../intl' '-W' '-Wall' '-Wstrict-prototypes' '-Wmissing-prototypes' '-g' '-O2' '-c' '-o' '/users/hblurfrushan/.ccache/tmp.hash.els-d60685.13738.o' '-mtune=generic' -- Summary: Optimization error when compiling bfd/ecofflink.c on x86_64 Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: dahowell at directv dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40216
[Bug c/40216] Optimization error when compiling bfd/ecofflink.c on x86_64
--- Comment #1 from dahowell at directv dot com 2009-05-21 03:47 --- Created an attachment (id=17897) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17897&action=view) ecofflink.i preprocessed source file -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40216
[Bug c/40216] Optimization error when compiling bfd/ecofflink.c on x86_64
--- Comment #3 from dahowell at directv dot com 2009-05-21 21:17 --- (In reply to comment #2) So this is a false negative for -Wstrict-aliasing=3. It is flagged by -Wstrict-aliasing=2, however. Is -Wstrict-aliasing=3 not catching it because the pointer is not being dereferenced, except in the called function? Perhaps passing a pointer to a function should be treated as a dereference for the purpose of generating a warning? This seems like something that could cause a lot of legacy code to fail in unexpected ways as the optimizer gets better. Should I submit a separate bug for this code failing to generate a warning with -Wall? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40216
[Bug c++/22167] New: Strange optimization bug when using -Os
The attached file osbugs.cpp will print a "BUG" message when compiled with
the -Os switch with g++ 3.4.4 on powerpc. This is due to the optimizer
generating incorrect code, by apparently incorrectly determining that S::p is
not being changed by the method S::init() before S::~S() is called.
I found this bug originally in the 3.3.5 version of the compiler, and it was
causing a strange crash down in the basic_string code, but I've been able
strip the code down to what I think is about the minimum needed to reproduce
the optimization failure. No pre-processor directives are in the attached
source file.
The bug has been reproduced in mips-linux 3.3.5, and i386-linux 3.3.2 and
3.3.5. The bug does not appear in i386-linux 3.4.4.
Sample output, showing that this bug occurs across several different
distributions of GCC:
powerpc, 3.4.4:
$ g++-3.4 --version | head -n1
g++-3.4 (GCC) 3.4.4 20050314 (prerelease) (Debian 3.4.3-13)
$ g++-3.4 -O2 osbugs.cpp -o osbugs
$ ./osbugs
p is 0x10011050 and p2 is 0x10011050 (should be non-zero and equal)
$ g++-3.4 -Os osbugs.cpp -o osbugs
$ ./osbugs
p is 0x0 and p2 is 0x0 (should be non-zero and equal)
BUG p is 0x10011050 and p2 is 0x0
i386, 3.3.5:
$ g++ --version | head -n1
g++ (GCC) 3.3.5 (Debian 1:3.3.5-13)
$ g++ -O2 osbugs.cpp -o osbugs
$ ./osbugs
p is 0x804a008 and p2 is 0x804a008 (should be non-zero and equal)
$ g++ -Os osbugs.cpp -o osbugs
$ ./osbugs
p is 0x0 and p2 is 0x0 (should be non-zero and equal)
BUG p is 0x804a008 and p2 is 0x0
i386, 3.3.2:
$ g++ --version | head -n1
g++ (GCC) 3.3.2 (Red Hat Linux 3.3.2-1)
$ g++ -O2 osbugs.cpp -o osbugs
$ ./osbugs
p is 0x8f0f008 and p2 is 0x8f0f008 (should be non-zero and equal)
$ g++ -Os osbugs.cpp -o osbugs
$ ./osbugs
p is 0x0 and p2 is 0x0 (should be non-zero and equal)
BUG p is 0x8497008 and p2 is 0x0
mips, 3.3.5:
$ mips-linux-g++ --version | head -n1
mips-linux-g++ (GCC) 3.3.5
$ mips-linux-g++ -O2 osbugs.cpp -o osbugs
[mipsbox]$ ./osbugs
p is 0x1240 and p2 is 0x1240 (should be non-zero and equal)
$ mips-linux-g++ -Os osbugs.cpp -o osbugs
[mipsbox]$ ./osbugs
p is 0x1240 and p2 is 0x0 (should be non-zero and equal)
BUG p is 0x1240 and p2 is 0x0
--
Summary: Strange optimization bug when using -Os
Product: gcc
Version: 3.4.4
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dahowell at directv dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: powerpc-linux
GCC host triplet: powerpc-linux
GCC target triplet: powerpc-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22167
[Bug c++/22167] Strange optimization bug when using -Os
--- Additional Comments From dahowell at directv dot com 2005-06-23 23:48 --- Created an attachment (id=9138) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9138&action=view) Short test file which demonstrates optimization failuer This is pretty much what was left of basic_string.h after I removed all the code which was not needed to cause the bug to happen. For the curious, S was derived from the basic_string template, A was derived from the allocator object, and p used to be the _M_rep pointer to the basic_string::_Rep structure. S::init was once basic_string::append. The function do_nothing was once the allocator's dispose method, but as you can see it now truly should do nothing. But it doesn't quite do nothing, it causes the optimizer to fail when optimizing for size. The seemingly pointless static_cast also is needed to cause the bug. Inlining either S::init or do_nothing will also make the bug magically disappear. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22167
[Bug c++/22167] Strange optimization bug when using -Os
-- What|Removed |Added Attachment #9138|Short test file which |Short test file which description|demonstrates optimization |demonstrates optimization |failuer |failure http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22167
