[Bug c++/67376] [5/6 regression] Comparison with pointer to past-the-end of array fails inside constant expression

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67376

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jason at gcc dot gnu.org

--- Comment #13 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #10)
> The a.e + 1 != 0 and a.e + 2 != 0 cases we used to fold them because
> try_move_mult_to_index would fold them into ADDR_EXPR of some field, which
> intentionally no longer happens.  So, I guess we want instead some
> simplification of POINTER_PLUS_EXPR<ADDR_EXPR<something>, INTEGER_CST> that
> would say use get_inner_reference on something, add (in offset_int?)  the
> constant offset to it and determine if it is always non-zero.

What if we restored try_move_mult_to_index for the case where the offset is
within the known bounds of an array?  That's the case that C++ is interested
in.