unsigned int i = 16;
return (((((i >= i) << i) >> i) <= i));
In section J.2 Undefined Behaviour, the standard mentions that it's undefined when "an expression is shifted by a negative number or by an amount greater than or equal to the width of the promoted expression"
[1] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf
It's basically a question about knowing when you'll get burned by the size of int varying.
(i >= i) // 1
((i >= i) << i) // 0x10000 or 0
(((i >= i) << i) >> i) // 1 or 0
(((((i >= i) << i) >> i) <= i)) // ((0 or 1) <= 16) == 1
UB.
> If the value of the right operand is negative
> or is greater than or equal to the width of
> the promoted left operand, the behavior is
> undefined"
Why would you bit-shift the result of a logical comparison?
This code makes no sense, it's wrong, and should be rewritten.