Recently i found that my C++ program was running fine with no
optimization and giving segmentation fault with error code 139 when
compiled with optimization level 2. I searched somewhat but never find
any systematic solution. In my recent attempt, i found the problem with
the optimization tool itself, which iam discussing here.
I found that the problem of segmentation fault was boiled down to a
statement of the form A = B, with no pointer or array usage, so forget
about the illegal memory write problems. When i removed this statement,
the problem disappers, so concluded that the segmentation fault problem
is with this statement. A careful study revealed that this statement
was redundant because A was never used in the program after this
statement. So i inserted one more statement after the above statement
which is "X = A", where X is a dummy variable and in that case the
problem again disappears. Inserting this new statement has made my
initial statement no more redundant.
I think the optimization tool had detected that A = B is a redundant
statement but failed to do its work. So its a clear bug in the
optimization tool itself.
The gcc -v output of my system is following:
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++ ,java,f95,objc, ada,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--program-suffix=-4.0 --enable-__cxa_atexit
--enable-libstdcxx-allocator=mt --enable-clocale=gnu
--enable-libstdcxx-debug --enable-java-gc=boehm --enable-java-awt=gtk
--enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-4.0-1.4.2.0/jre
--enable-mpfr --disable-werror --enable-checking=releas e i486-linux-gnu
Thread model: posix
gcc version 4.0.2 (Debian 4.0.2-2)
3  2253 
"Abhishek" <ab************ @gmail.com> wrote in message
| Recently i found that my C++ program was running fine with no
| optimization and giving segmentation fault with error code 139 when
| compiled with optimization level 2. I searched somewhat but never find
| any systematic solution. In my recent attempt, i found the problem with
| the optimization tool itself, which iam discussing here.
You should take the topic to the gcc mailing list.
Sharad
Abhishek wrote:
[g++ bug report redacted]
Bug reports for particular compilers are off-topic in this group. All we can
do is help you determine whether there is actually a bug. Since you did not
post the code, which may or may not exhibit undefined behavior, we cannot
help with that either.
Best
Kai-Uwe Bux
Abhishek wrote: Recently i found that my C++ program was running fine with no
optimization and giving segmentation fault with error code 139 when
compiled with optimization level 2. I searched somewhat but never find
any systematic solution. In my recent attempt, i found the problem with
the optimization tool itself, which iam discussing here.
I found that the problem of segmentation fault was boiled down to a
statement of the form A = B, with no pointer or array usage, so forget
about the illegal memory write problems. When i removed this statement,
the problem disappers, so concluded that the segmentation fault problem
is with this statement. A careful study revealed that this statement
was redundant because A was never used in the program after this
statement. So i inserted one more statement after the above statement
which is "X = A", where X is a dummy variable and in that case the
problem again disappears. Inserting this new statement has made my
initial statement no more redundant.
I think the optimization tool had detected that A = B is a redundant
statement but failed to do its work. So its a clear bug in the
optimization tool itself.
Without any more code, it's hard to say if you're right. What type are A and
B? Could you provide a minimal, but complete program that shows the
behavior. Sometimes, a program crash happens in a place different from the
one that contains the error.
As others already mentioned: A g++ bug report would have to go to a
different place than here, but here, we could tell you if it's actually a
bug in the compiler or an error in your code. However, for that, you'd have
to show some code. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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Environment
-----------
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