[Bug c/57209] New: Wrong code of print statement

[ishiura-compiler at ml dot kwansei.ac.jp]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57209



             Bug #: 57209

           Summary: Wrong code of print statement

    Classification: Unclassified

           Product: gcc

           Version: 4.8.1

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c

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

        ReportedBy: ishiura-compi...@ml.kwansei.ac.jp





The following code is miscompiled by GCC 4.8.1 20130508 (prerelease)

for x86_64 (as well as for i686).  The option in question is

"-funsafe-math-optimizations."



  $ cat error.c



  volatile char buff = 0;

  void PRINTF(const char* s)

  {

    while(*s++) buff = *s;

  }



  int main (void)

  {

    int k = -1;

    int t = 1 % (int)(( 942.0 + k ) / -941.0F );

    if (t == 0) { PRINTF("OK"); }

    return 0;

  }



  $ x86_64-unknown-linux-gnu-gcc-4.8.1 error.c -O1 -funsafe-math-optimizations

  $ ./a.out

  Floating point exception (core dumped)



-----



$ x86_64-unknown-linux-gnu-gcc-4.8.1 -v

Using built-in specs.

COLLECT_GCC=x86_64-unknown-linux-gnu-gcc-4.8.1

COLLECT_LTO_WRAPPER=/usr/local/x86_64-tools/gcc-4.8.1/libexec/gcc/x86_64-unknown-linux-gnu/4.8.1/lto-wrapper

Target: x86_64-unknown-linux-gnu

Configured with: /home/hassy/gcc/configure

--prefix=/usr/local/x86_64-tools/gcc-4.8.1/

--with-gmp=/usr/local/gmp-5.1.1/ --with-mpfr=/usr/local/mpfr-3.1.2/

--with-mpc=/usr/local/mpc-1.0.1/ --disable-multilib --disable-nls

--enable-languages=c

Thread model: posix

gcc version 4.8.1 20130508 (prerelease) (GCC)