[llvm-branch-commits] [llvm] AMDGPU: Make vector_shuffle legal for v2i32 with v_pk_mov_b32 (PR #123684)

via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Mon Jan 20 20:36:15 PST 2025


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)' 2d8035aff3d44bd59f4ff3af60f87c7d6e6219ea c5caf560857f3c4f71416940a528df5ce75212bc llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.h llvm/lib/Target/AMDGPU/SIISelLowering.cpp llvm/test/CodeGen/AMDGPU/shufflevector.v2f32.v2f32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2f32.v3f32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2f32.v4f32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2f32.v8f32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2i32.v2i32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2i32.v3i32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2i32.v4i32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2i32.v8i32.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2p3.v2p3.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2p3.v3p3.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2p3.v4p3.ll llvm/test/CodeGen/AMDGPU/shufflevector.v2p3.v8p3.ll llvm/test/CodeGen/AMDGPU/shufflevector.v4i64.v3i64.ll llvm/test/CodeGen/AMDGPU/shufflevector.v4p0.v3p0.ll llvm/test/CodeGen/AMDGPU/vector_shuffle.packed.ll llvm/test/Transforms/InferAddressSpaces/AMDGPU/flat_atomic.ll
``````````

</details>


The following files introduce new uses of undef:
 - llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp

[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/123684


More information about the llvm-branch-commits mailing list