http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55885



             Bug #: 55885

           Summary: Modulo operator crashes for int and long variables if

                    they have minimal value

    Classification: Unclassified

           Product: gcc

           Version: 4.2.1

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c++

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: klaus.wie...@endolandia.de





Error description in source file

-------------------------------------



Compiled with

-------------------------------------

i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658)

(LLVM build 2336.11.00) on MAC OS X Version 10.7.5 (Lion)

-------------------------------------



Result of gcc -v:

-------------------------------------

Using built-in specs.

Target: i686-apple-darwin11

Configured with: /private/var/tmp/llvmgcc42/llvmgcc42-2336.11~67/src/configure

--disable-checking --enable-werror

--prefix=/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2

--mandir=/share/man --enable-languages=c,objc,c++,obj-c++

--program-prefix=llvm- --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/

--with-slibdir=/usr/lib --build=i686-apple-darwin11

--enable-llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.11~67/dst-llvmCore/Developer/usr/local

--program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11

--target=i686-apple-darwin11 --with-gxx-include-dir=/usr/include/c++/4.2.1

Thread model: posix

gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)

-------------------------------------



Compiler and linker output

-------------------------------------

make all 

Building file: ../src/iotest.cpp

Invoking: GCC C++ Compiler

g++ -O0 -g3 -Wall -Wextra -c -fmessage-length=0 -MMD -MP -MF"src/iotest.d"

-MT"src/iotest.d" -o "src/iotest.o" "../src/iotest.cpp"

Finished building: ../src/iotest.cpp



Building target: iotest

Invoking: MacOS X C++ Linker

g++  -o "iotest"  ./src/iotest.o   

Finished building target: iotest

-------------------------------------



Compiling with options -fno-strict-aliasing -fwrapv does not make a difference

-------------------------------------



file: iotest.cpp

-------------------------------------

#include <iostream>

#include <limits>



// Assumption: If a is a signed variable, then a % -1 should always be 0

//

// ok    if myType is of type char or short

// fails if myType is of type int  or long



int main() {



    typedef int myType;



    myType c;



    myType a = std::numeric_limits<myType>::min();

    int    b = -1;



        // always ok

    c = a % -1;

    std::cout << a << ", " << b << ", " << c << std::endl;



        // signals EXC ARITHMETIC:Arithmetic exception 

        // if myType is int or is long 

    c = a % b;

        std:: cout << a << ", " << b << ", " << c << std::endl;



    return 0;

}

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