[all-commits] [llvm/llvm-project] b980d2: [unittest] Exercise SCEV's udiv and udiv ceiling r...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b980d2f54bb652208eeb9a6543b8d838b65ad099
      https://github.com/llvm/llvm-project/commit/b980d2f54bb652208eeb9a6543b8d838b65ad099
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2021-07-15 (Thu, 15 Jul 2021)

  Changed paths:
    M llvm/include/llvm/Analysis/ScalarEvolution.h
    M llvm/unittests/Analysis/ScalarEvolutionTest.cpp

  Log Message:
  -----------
  [unittest] Exercise SCEV's udiv and udiv ceiling routines

The ceiling variant was recently added (due to the work towards D105216), and we're spending a lot of time trying to find optimizations for the expression. This patch brute forces the space of i8 unsigned divides and checks that we get a correct (well consistent with APInt) result for both udiv and udiv ceiling.

(This is basically what I've been doing locally in a hand rolled C++ program, and I realized there no good reason not to check it in as a unit test which directly exercises the logic on constants.)

Differential Revision: https://reviews.llvm.org/D106083