Refining the Reduced LLVM IR and Bug Reporting

If you just get a `segfault` there is no sensible error message and not much to do automatically, so continue to 5). otherwise, create a `script.sh` file containing ```sh #!/bin/bash <path/to/your/opt> $1 -load-pass-plugin=/path/to/llvmenzyme-19.so -passes="enzyme" \ |& grep "/some/path.cpp:686: void llvm::callinst::init" ``` Experiment a bit with which error message you pass to grep. it should be long enough to make sure that the error is unique. However, for longer errors including `(` or `)` you will need to escape them correctly which can become annoying. Run ```sh <path/to/llvm-reduce> --test=script.sh mwe.ll ``` If you see `input isn't interesting! verify interesting-ness test`, you got the error message in script.sh wrong, you need to make sure that grep matches your actual error. If all works out, you will see a lot of iterations, ending with a new `reduced.ll` file. Verify with `opt` that you still get the same error. ### Advanced debugging: manual llvm-ir investigation Once you have a minimized reproducer (`mwe.ll` or `reduced.ll`), you can delve deeper: - **manual editing:** try manually rewriting the llvm-ir. for certain issues, like those involving indirect calls, you might investigate enzyme-specific intrinsics like `__enzyme_virtualreverse`. Understanding how to use these might require consulting enzyme's documentation or source code. - **enzyme test cases:** look for relevant test cases within the [enzyme repository](https://github.com/enzymead/enzyme/tree/main/enzyme/test) that might demonstrate the correct usage of features or intrinsics related to your problem. ## 5) Report your bug. Afterwards, you should be able to copy and paste your `mwe.ll` (or `reduced.ll`) example into our [compiler explorer](https://enzyme.mit.edu/explorer/). - Select `llvm ir` as language and `opt 20` as compiler. - Replace the field to the right of your compiler with `-passes="enzyme"`, if it is not already set. - Hopefully, you will see once again your now familiar error.

This section describes how to refine the reduced LLVM IR further by manually editing it and consulting Enzyme's documentation or source code. It also explains how to use the Enzyme test cases for reference. It guides the user to report the bug by pasting the minimized LLVM IR into the Enzyme compiler explorer, selecting the appropriate settings, and verifying the error.