tree 0417e1810db5f89bc55616c68cef965107f01b53
parent 459cb8435ed3bf3e12891aace5edbf2a74b65c7a
author Roman Lebedev <lebedev.ri@gmail.com> 1602489652 +0300
committer Copybara-Service <copybara-worker@google.com> 1604025708 -0700

[SCEV] Model ptrtoint(SCEVUnknown) cast not as unknown, but as zext/trunc/self of SCEVUnknown

While we indeed can't treat them as no-ops, i believe we can/should
do better than just modelling them as `unknown`. `inttoptr` story
is complicated, but for `ptrtoint`, it seems straight-forward
to model it just as a zext-or-trunc of unknown.

This may be important now that we track towards
making inttoptr/ptrtoint casts not no-op,
and towards preventing folding them into loads/etc
(see D88979/D88789/D88788)

Reviewed By: mkazantsev

Differential Revision: https://reviews.llvm.org/D88806

GitOrigin-RevId: 1c021c64caef83cccb719c9bf0a2554faa6563af