[all-commits] [llvm/llvm-project] 6fa65f: [Polly][MatMul] Abandon dependence analysis.

[Michael Kruse via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6fa65f8a98967a5d2d2a6863e0f67a40d2961905
      https://github.com/llvm/llvm-project/commit/6fa65f8a98967a5d2d2a6863e0f67a40d2961905
  Author: Michael Kruse <llvm-project at meinersbur.de>
  Date:   2022-06-29 (Wed, 29 Jun 2022)

  Changed paths:
    M polly/include/polly/DependenceInfo.h
    M polly/lib/Analysis/DependenceInfo.cpp
    M polly/lib/Transform/MatmulOptimizer.cpp
    M polly/lib/Transform/ScheduleOptimizer.cpp
    M polly/test/CodeGen/OpenMP/matmul-parallel.ll
    M polly/test/ScheduleOptimizer/pattern-matching-based-opts.ll

  Log Message:
  -----------
  [Polly][MatMul] Abandon dependence analysis.

The copy statements inserted by the matrix-multiplication optimization
introduce new dependencies between the copy statements and other
statements. As a result, the DependenceInfo must be recomputed.

Not recomputing them caused IslAstInfo to deduce that some loops are
parallel but cause race conditions when accessing the packed arrays.
As a result, matrix-matrix multiplication currently cannot be
parallelized.

Also see discussion at https://reviews.llvm.org/D125202