[cfe-dev] Question about Clang codegen tests

[Jun via cfe-dev]

Hello, everyone!



I'm a newcomer, and want to make some contributions to the LLVM community. Is here the right place to reach out for help? Please forgive me if I did things wrong, as I'm unfamiliar with the LLVM workflow :-) 



So a few days ago I noticed an issue in the bugzilla: https://bugs.llvm.org/show_bug.cgi?id=52444, I thought it would be suitable for me to work on. But now I run into some problems:



* What is meaning of the capitalized words in tests comments?

For example,  in `llvm-project/clang/test/CodeGen/builtins-elementwise-math.c`:

```

// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s

// CHECK-LABEL: define void @test_builtin_elementwise_abs(
  

// CHECK:      [[F1:%.+]] = load float, float* %f1.addr, align 4
  

// CHECK-NEXT:  call float @llvm.fabs.f32(float [[F1]])

```

What do `RUN`, `CHECK` mean? I can guess they are some test instructions, so I briefly look through the docs, but I can't find anything useful :-( I'm sorry but the docs are so much, it's hard to find something I actually don't know what is.



* How can I write my own test for codegen?

The actual code part is not that hard, problems came in when I want to write some tests. The fact is that I'm unfamiliar with LLVM IR, so I don't know how to write the expected output...



Thanks so much for people who offer me help!



Best regards,

Jun Zhang
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20211125/ed635e04/attachment.html>