[PATCH] D70609: [DDG] Data Dependence Graph - Topological Sort

[Michael Kruse via Phabricator via llvm-commits]

Meinersbur added a comment.

[suggestion] Could you add a test case with a reduction (not necessarily in this patch), such as

  double sum = 0;
  for (int i = 0; i < n; i+=1)
    sum+=A[i];
  return sum;

I am interested in what happens in self-recursive phi dependencies that are not induction variables. Note that GVN LoadPRE and LICM register promotion can create those as well. Another interesting case would be a nested reduction:

  for (int j = 0; j < m; j+=1) {
    double sum = 0;
    for (int i = 0; i < n; i+=1)
      sum += A[i][j];
    B[j] = sum;
  }

The motivation is that reductions usually are optimized differently than flow dependencies.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D70609/new/

https://reviews.llvm.org/D70609