[PATCH] enhance -Warray-bounds to detect out-of-bounds offsets (PR 82455)

[Martin Sebor]

>> I of course don't want to break anything.  I didn't see any fallout
>> in my testing and I normally test all the front ends, including Ada,
>> but let me check to make sure I tested it this time (I had made some
>> temporary changes to my build script and may have disabled it.)Â  Let
>> me double check it after I get back from my trip.
> No worries.  Hopefully by the time you're back I'll have something
> publishable on the ripping apart tree-vrp front and we can prototype the
> effectiveness of doing this kind of stuff outside tree-vrp.c

I re-did my build and re-ran all the tests and found no regressions
in the Ada tests.

> We should also revisit Aldy's work from last year which started the
> whole effort around fixing how we deal with out out of bounds index
> testing.   He had a version which ran outside tree-vrp.c but used the
> same basic structure and queried range data for the index.  I've got a
> copy here we can poke at.

Sure, I'd be interested in looking at it when I'm done with this
work.

Martin