Re: [Tinycc-devel] More fun with comparison between pointer and integer...

[Simon 'corecode' Schubert]

Rob Landley wrote:
> On Wednesday 05 September 2007 6:17:38 pm Rob Landley wrote:
> > Hang on, so when char *a is constant, (int)a is _not_ constant?
> >
> > How does that work?
>
> Looking back at it, I think what the standard means is since the actual 
> address of the char * is supplied by the linker, than despite it being a 
> run-time constant it can't be known at compile time.
>
> However, we can know that it's nonzero which is all && and || need, so I can 
> teach _them_ about propogating constant values from pointers.

Actually it is the implicit comparison to NULL which can propagate the 
constant and || and && then turn can operate on this constant, producing 
a constant result in the end.

cheers
  simon