RE: [avr-gcc-list] An old but unfixed bug

[Jeremy Moc]

Hi Alexander,  I don't think this is a gcc bug per se.  Your while condition
is comparing an int (0xffff == -1) cast to a pointer.  If your pointer p is
initialised to any value <= 0x7fff your while condition fails on the first
pass.  The source file you sent showed p = RAMEND + 1.  Usually a small
positive number (eg. 4433 --> 0x15F + 1) so you have:
        while ( 352 < -1 );  // fail
Hope this helps,

Jeremy Moc


>       Hello,
>       Here I send a warning for an old bug which is still not
> fixed. It is a general
> GCC bug, not AVR specific.
>       When we have :
>
>       unsigned char *p;
>       p=(unsigned char*)SOME_ADDR;
>       do {
>         // do something
>         } while(p++<(unsigned char *)0xffff);
>
>       The while loop is totaly skipped and the body is executed only once!
>
>       Best regards,
>       Alexander Popov
>