CIRCT now in Compiler Explorer (

MLIR was recently added to Compiler Explorer: Looking for ideas and requests regarding MLIR for Compiler Explorer (

Inspired by that, I went through the steps and with some help, got CIRCT added as well. The Compiler Explorer CI builds a fairly recent version of circt-opt from CIRCT trunk periodically, and makes that available in the UI.

You can write any IR circt-opt understands in the editor pane (1), and use the compiler option pane (2) to spell out pass pipelines.

Here’s a live link to the above: Compiler Explorer.

So far, we just have basic circt-opt support. Some further ideas I’d like to explore:

  • Connect mlir-opt runs to circt-opt runs, to be able to show some HLS flows
  • Install Chisel, PyCDE, etc., and be able to run these frontends to CIRCT in Compiler Explorer

If you have any feedback or other ideas, please let me know!



Super cool!