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Re: basic_block index negative?
On Wed, 17 Oct 2001, Daniel Egger wrote:
> Am Mit, 2001-10-17 um 19.46 schrieb 1003340807:
>
> > Dunno. I guess because they're special and contain no program
> > instructions. The tree SSA code uses it to tell whether it found
> > a ghost definition (artificial definitions created by SSA).
>
> I find it quite odd and distracting to have negative indices. This
> also forbids using them for arrays.
>
True.
> I think it would be really nice to mostly unsigned variables; this
> makes it easy to prevent nasty sideeffects when dealing with them
> and quite frankly I don't like the just of casts in the code. Maybe
> gcc could also create better code but this is just a speculation
> for recent versions, it worked on older versions though.
>
Even if you didn't allow negative indices, reverse traversals are
important. Making the index unsigned would make them more
interesting than they need to be.
Diego.