[LLVMdev] promotion of return value.

[Duncan Sands]

> I think syntax along the lines of signext(13) and zeroext(13) would  
> make sense.

Yes, while knowing that something was extended from i13 is not too
useful for ABI stuff, the optimizers might want to add such attributes
if they work out that the returned value is always extended from the
lower 13 bits for example.  This is also useful for languages like Ada
which may know that several top bits are always zero etc due to their
strong type system.

Ciao,

Duncan.