In the file below (also in the archive attached), compiling with any form of optimisation via a gcc wrapper script produces code, in downcase(), that does an increment-and-store instead of store-and-increment on the *s++ = rval statement. The result is that the first character of any string is lost. I encountered this problem first in gcc 3.2.0, and it persists in gcc 3.2.2.

Additionally, when the file is compiled by direct evocation of the compiler (gcc32.2 -s -o tdowncase tdowncase.c), the programme crashes on the wrongly compiled line.

The attached archive contains
* tdowncase.c : the source
* gccopt : my wrapper script
* coredumps.tar : archive containing the temp files, binary and coredump for the crashing version, as well as the log of the compilation and execution
* wrongcode.tar : idem for the non-crashing, wrong-result version, with the log



/* tdowncase: a case of wrong optimisation */
#include <stdio.h>
#include <ctype.h>

void downcase( char *s )
{
   while( *s ){
          *s++= tolower( *s );
            /* gcc 3.2.0 linux seems to have a bug in that *s++=tolower(*s) becomes
             \ *++s=tolower(*s) ?!
             */
/*        s++; */
   }
}

main()
{ char *c1= "ABCDE",
       *c2= "efghi";

     printf( "downcase(\"%s\")=\"", c1 ); fflush(stdout);
     downcase(c1);
     printf( "%s\"\n", c1 );
     printf( "downcase(\"%s\")=\"", c2 ); fflush(stdout);
     downcase(c2);
     printf( "%s\"\n", c2 );
}

Release:
3.2.0 and 3.2.2

Environment:
Linux 2.2.13-7mdk PIII, glibc 2.1.3
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ../gcc-3.2.2/configure --prefix=/usr/local/gcc3.2.2 --enable-languages=c,c++,f77,objc --disable-nls --with-system-zlib

How-To-Repeat:
compile and run...