Re: [COMMITTED] Allow ranger queries on exit block.

[Richard Biener <richard.guenther@gmail.com>]

On Tue, Nov 1, 2022 at 2:20 PM Andrew MacLeod via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Ranger was not allowing the exit block to be queried for range_on_entry
> or exit, for no good reason.  This removes that restriction.
>
> Interestingly, it seems that when we calculate dominance info, GCC does
> not set the dominators for the EXIT_BLOCK?  I worked around it by
> starting with a single pred of the exit block for my queries, but as a
> result it doesn't support multiple exit blocks.
>
> For the record:
>
>    get_immediate_dominator (CDI_DOMINATORS, EXIT_BLOCK_PTR_FOR_FN (cfun))
>
> returns NULL.   Is this actually working as intended?  It was unexpected
> on my part.

Yes, working as "intended".  EXIT and ENTRY
basic-blocks are artificial so having dominance info for them would be
somewhat odd.

Richard.

>
> Bootstrapped on x86_64-pc-linux-gnu with no regressions.  Pushed.
>
> Andrew