[avr-gcc-list] avr-gcc bug (Win)

[Peter Bosscha]

Hi,

 

Found a bug in branch logic together with the BRGE instruction.

I'm using avr-libc-20010211 and -O2 and -Os give the same (erroneous) result.

Tried to simplify this as much as possible so the code is a joke.

 

Have a look at the following:

 

unsigned char mycall(unsigned char parm)
{
 return 0x80;
}

 

int main(void)
{
unsigned char i,a,b;

 

 a=mycall(0);
 b=mycall(1);
 do {
  if (a) {
   i = mycall(0);
   if (i & 0x80) {
    mycall(1);
   } else {
    if (b) {
     mycall(2);
    }
   }
  }
 } while(1);
 return 1;
}

In this example the jump at if (i & 0x80) goes the wrong way.

 

- Change the statement to if (i) and the problem goes away

- Change the nesting level (comment out the outer do-while) and the problem goes away

- Take out the if (b) and the problem goes away

 

Changing the outer while into for(;;) does not help either.

 

So ... 2 questions:

 

- is everyone else getting this too ?

- if so, where to report this ?

 

Greetings

Peter Bosscha

 

P.S. The Mime bit is not my idea, talk to my Sysadmin if you don't like it..