[llvm] [KernelInfo] Implement new LLVM IR pass for GPU code analysis (PR #102944)

via llvm-commits llvm-commits at lists.llvm.org
Fri Dec 27 11:12:42 PST 2024


github-actions[bot] wrote:

<!--LLVM CODE FORMAT COMMENT: {undef deprecator}-->


:warning: undef deprecator found issues in your code. :warning:

<details>
<summary>
You can test this locally with the following command:
</summary>

``````````bash
git diff -U0 --pickaxe-regex -S '([^a-zA-Z0-9#_-]undef[^a-zA-Z0-9_-]|UndefValue::get)' 9ab16d49c99966f33900d68ed5370f19927ca52c 8982f8ff551bd4c11d47afefe97364c3a5c25ec8 llvm/include/llvm/Analysis/KernelInfo.h llvm/lib/Analysis/KernelInfo.cpp llvm/test/Analysis/KernelInfo/allocas.ll llvm/test/Analysis/KernelInfo/calls.ll llvm/test/Analysis/KernelInfo/enable-kernel-info/Inputs/test.ll llvm/test/Analysis/KernelInfo/flat-addrspace/Inputs/test.ll llvm/test/Analysis/KernelInfo/launch-bounds/amdgpu.ll llvm/test/Analysis/KernelInfo/launch-bounds/nvptx.ll llvm/test/Analysis/KernelInfo/linkage.ll llvm/test/Analysis/KernelInfo/openmp/amdgpu.ll llvm/test/Analysis/KernelInfo/openmp/nvptx.ll llvm/include/llvm/Analysis/TargetTransformInfo.h llvm/include/llvm/Analysis/TargetTransformInfoImpl.h llvm/include/llvm/Target/TargetMachine.h llvm/lib/Analysis/TargetTransformInfo.cpp llvm/lib/Passes/PassBuilder.cpp llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.h llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp llvm/lib/Target/NVPTX/NVPTXTargetTransformInfo.cpp llvm/lib/Target/NVPTX/NVPTXTargetTransformInfo.h llvm/lib/Target/TargetMachine.cpp
``````````

</details>


The following files introduce new uses of undef:
 - llvm/test/Analysis/KernelInfo/openmp/nvptx.ll

[Undef](https://llvm.org/docs/LangRef.html#undefined-values) is now deprecated and should only be used in the rare cases where no replacement is possible. For example, a load of uninitialized memory yields `undef`. You should use `poison` values for placeholders instead.

In tests, avoid using `undef` and having tests that trigger undefined behavior. If you need an operand with some unimportant value, you can add a new argument to the function and use that instead.

For example, this is considered a bad practice:
```llvm
define void @fn() {
  ...
  br i1 undef, ...
}
```

Please use the following instead:
```llvm
define void @fn(i1 %cond) {
  ...
  br i1 %cond, ...
}
```

Please refer to the [Undefined Behavior Manual](https://llvm.org/docs/UndefinedBehavior.html) for more information.



https://github.com/llvm/llvm-project/pull/102944


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