tree 4209101c1244d16b4bf816f472ad289032c21d82
parent 34c654c4c141f97b8d7968c0824efca6b41a25c9
author Roman Lebedev <lebedev.ri@gmail.com> 1615615946 +0300
committer Copybara-Service <copybara-worker@google.com> 1616071656 -0700

Reland [SCEV] Improve modelling for (null) pointer constants

This reverts commit 329aeb5db43f5e69df038fb20d2def77fe6f8595,
and relands commit 61f006ac655431bd44b9e089f74c73bec0c1a48c.

This is a continuation of D89456.

As it was suggested there, now that SCEV models `PtrToInt`,
we can try to improve SCEV's pointer handling.
In particular, i believe, i will need this in the future
to further fix `SCEVAddExpr`operation type handling.

This removes special handling of `ConstantPointerNull`
from `ScalarEvolution::createSCEV()`, and add constant folding
into `ScalarEvolution::getPtrToIntExpr()`.
This way, `null` constants stay as such in SCEV's,
but gracefully become zero integers when asked.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D98147

GitOrigin-RevId: 78b8ce40efeb578534543fcb948cb9db22e5b81f