[PATCH] D35858: [RFC] [LLVM] [LazyValueInfo] Introduce getRecurringEdgeValue to handle simple recurrence

[Hongbin Zheng via Phabricator via llvm-commits]

etherzhhb created this revision.

Teach LazyValueInfo to handle simple patterns on the PHINodes, including:

1. Induction variable of natural loop that increased by 1
2. select (phi (init, select)) generated from linear search

This is accomplished by computing the value of PHINode recurring edge based on mathematical fixed-point. We will fallback to getEdgeValue if we cannot handle the recurring edge.

PS: How should I add unittest for this? since it is "lazy". maybe I should come back with a LazyValueInfo printer


Repository:
  rL LLVM

https://reviews.llvm.org/D35858

Files:
  lib/Analysis/LazyValueInfo.cpp

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