On Fri, 23 Apr 2010 19:53:24 BST C H Forsyth <[email protected]> wrote:
> >As per C89 in this case the unsigned char value should be
> >promoted to a *signed* int value. The sum will be of type
> >signed int and so the division will do the right thing. In
> >kencc case it seems the sum has type unsigned int for some
> >reason and further, the signed divisor (2) is promoted to an
> >unsigned int. Seems like a bug.
>
> on 19 April, I wrote:
> >notably the compiler doesn't implement the value-preserving rules for compar
> isons. ...
> >instead the compiler implements the older unsigned-preserving rule
Does the following assertion fail under plan9?
int x = 1234, y = -4321;
unsigned char z = 12;
int r1, r2;
r1 = (x + y + z)/2;
x += z;
r2 = (x + y)/2;
assert(r1 == r2);
If so, I consider it a bug; particularly as there is no
overflow involved anywhere.
