[all-commits] [llvm/llvm-project] 0b2041: Revert "[Canonicalizer] Process regions top-down i...

[Uday Bondhugula via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0b20413ef6717d914a8b8a9ece86d8eae27c221f
      https://github.com/llvm/llvm-project/commit/0b20413ef6717d914a8b8a9ece86d8eae27c221f
  Author: Uday Bondhugula <uday at polymagelabs.com>
  Date:   2021-03-25 (Thu, 25 Mar 2021)

  Changed paths:
    M mlir/include/mlir/Transforms/FoldUtils.h
    M mlir/include/mlir/Transforms/GreedyPatternRewriteDriver.h
    M mlir/lib/Transforms/Utils/FoldUtils.cpp
    M mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
    M mlir/test/Conversion/VectorToSCF/vector-to-loops.mlir
    M mlir/test/Dialect/Affine/canonicalize.mlir
    M mlir/test/Dialect/Linalg/transform-patterns.mlir
    M mlir/test/Dialect/Vector/canonicalize.mlir
    M mlir/test/Transforms/canonicalize.mlir
    M mlir/test/mlir-tblgen/pattern.mlir

  Log Message:
  -----------
  Revert "[Canonicalizer] Process regions top-down instead of bottom up & reuse existing constants."

This reverts commit 361b7d125b438cda13fa45f13790767a62252be9 by Chris
Lattner <clattner at nondot.org> dated Fri Mar 19 21:22:15 2021 -0700.

The change to the greedy rewriter driver picking a different order was
made without adequate analysis of the trade-offs and experimentation. A
change like this has far reaching consequences on transformation
pipelines, and a major impact upstream and downstream. For eg., one
can’t be sure that it doesn’t slow down a large number of cases by small
amounts or create other issues. More discussion here:
https://llvm.discourse.group/t/speeding-up-canonicalize/3015/25

Reverting this so that improvements to the traversal order can be made
on a clean slate, in bigger steps, and higher bar.

Differential Revision: https://reviews.llvm.org/D99329