[all-commits] [llvm/llvm-project] 1202d2: [SCEV][NFC] Reduce memory footprint & compile time...

[Max Kazantsev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1202d280c6d96d6ad85d7e3d9f0968a7331f4322
      https://github.com/llvm/llvm-project/commit/1202d280c6d96d6ad85d7e3d9f0968a7331f4322
  Author: Max Kazantsev <mkazantsev at azul.com>
  Date:   2021-10-15 (Fri, 15 Oct 2021)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp

  Log Message:
  -----------
  [SCEV][NFC] Reduce memory footprint & compile time via DFS refactoring

Current implementations of DFS in SCEV check unique-visited of traversed
values on pop, and not on push. As result, the same value may be pushed
multiple times just to be thrown away when popped. These operations are
meaningless and only waste time and increase memory footprint of the
worklist.

This patch reworks the DFS strategy to check uniqueness before push.
Should be NFC.

Differential Revision: https://reviews.llvm.org/D111774
Reviewed By: nikic, reames