[LangRef] Clarify `dereferenceable` -> `nonnull` implication
authorJohannes Doerfert <johannes@jdoerfert.de>
Wed, 14 Oct 2020 18:54:20 +0000 (13:54 -0500)
committerJohannes Doerfert <johannes@jdoerfert.de>
Wed, 28 Oct 2020 00:12:53 +0000 (19:12 -0500)
commit14077836ec0575320042585a80e4227bb0ee5be0
treecb85676bd127827f3e1da0e0920d5611fe3eb495
parentb1a90e1599a65bccf9af985603e198af3876b59a
[LangRef] Clarify `dereferenceable` -> `nonnull` implication

If `null_pointer_is_valid` is present, `dereferenceable` does not imply
`nonnull`, make it clear.

Came up in D17993.

Reviewed By: aqjune

Differential Revision: https://reviews.llvm.org/D89417
llvm/docs/LangRef.rst