[cfe-dev] mixed types with BO_Sh[rl]

[Chris Lattner]

On Jan 27, 2011, at 3:19 AM, Roman Divacky wrote:

> hi,
> 
> in a simple expression like:
> 
>  unsigned int _x;
> 
>  return (_x >> 30);
> 
> the BinaryOperator is formed like this:
> 
> (BinaryOperator 0x8018dc1a0 'unsigned int' '>>'
>  (DeclRefExpr 0x8018dc140 'unsigned int' lvalue Var='_x' 0x80188ff70)
>  (IntegerLiteral 0x8018dc170 'int' 30))
> 
> note the mixed operands with 'unsigned int' and 'int' types.
> 
> Is this by design or by mistake? I guess there should be IntegralCast
> for the 'int' 30, right? This happens only for Shr/Shl operators,
> all others have the IntegralCast I would expect here.

Hi Roman,

This is actually by design.  C doesn't constrain the shift amount to be the same type as the LHS of the shift.

-Chris