[all-commits] [llvm/llvm-project] e38c8b: [MLIR][scf.parallel] Don't allow a tile size of 0 ...

[Justin Fargnoli via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e38c8bdca8ca1c05d8e6e2e665524c0841fb13d3
      https://github.com/llvm/llvm-project/commit/e38c8bdca8ca1c05d8e6e2e665524c0841fb13d3
  Author: Justin Fargnoli <34139864+justinfargnoli at users.noreply.github.com>
  Date:   2023-10-23 (Mon, 23 Oct 2023)

  Changed paths:
    M mlir/lib/Dialect/SCF/Transforms/ParallelLoopTiling.cpp
    A mlir/test/Dialect/SCF/parallel-loop-invalid.mlir

  Log Message:
  -----------
  [MLIR][scf.parallel] Don't allow a tile size of 0 (#68762)

Fix a crash reported in #64331. The crash is described in the following
comment:

> It looks like the bug is being caused by the command line argument
--scf-parallel-loop-tiling=parallel-loop-tile-sizes=0. More
specifically, --scf-parallel-loop-tiling=parallel-loop-tile-sizes sets
the tileSize variable to 0 on [this
line](https://github.com/llvm/llvm-project/blob/7cc1bfaf371c4a816cf4e62fe31d8515bf8f6fbd/mlir/lib/Dialect/SCF/Transforms/ParallelLoopTiling.cpp#L67).
tileSize is then used on [this
line](https://github.com/llvm/llvm-project/blob/7cc1bfaf371c4a816cf4e62fe31d8515bf8f6fbd/mlir/lib/Dialect/SCF/Transforms/ParallelLoopTiling.cpp#L117)
causing a divide by zero exception.

This PR will:

1. Call `signalPassFail()` when 0 is passed as a tile size.
2. Avoid the divide by zero that causes the crash. 

Note: This is my first PR for MLIR, so please liberally critique it.