Parameter pass bug ??

The following code works in Carm Compiler and it doesn't work in Realview Compiler !!
What's happening ?

char func(char x1, char x2)
{
 return(x1+x2);
}

char teste(char c1, char c2)
{
 func(4,5);
 return (c1+c2); // in this point c1 and c2 crashed !!
}

int main(void)
{
 teste(1,2);
 while(1);
}