[lldb] [llvm] [mlir] [DebugInfo] Add symbolic branches to DIExpression (PR #210850)

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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)' 'HEAD~1' HEAD llvm/test/Assembler/di-expression-symbolic-branches.ll llvm/test/Bitcode/di-expression-symbolic-branches.ll llvm/test/DebugInfo/PowerPC/di-expression-symbolic-branches.ll llvm/test/DebugInfo/X86/di-expression-symbolic-branch-arg0.ll llvm/test/DebugInfo/X86/di-expression-symbolic-branch-convert-boundary.ll llvm/test/DebugInfo/X86/di-expression-symbolic-branch-out-of-range.ll llvm/test/DebugInfo/X86/di-expression-symbolic-branch-register.ll llvm/test/DebugInfo/X86/di-expression-symbolic-branch-sdag-salvage.ll llvm/test/DebugInfo/X86/di-expression-symbolic-branches.ll llvm/test/Verifier/di-expression-symbolic-branches.ll mlir/test/Target/LLVMIR/Import/debug-info-symbolic-branches.ll lldb/source/Expression/DWARFExpression.cpp llvm/include/llvm/BinaryFormat/Dwarf.h llvm/include/llvm/IR/DebugInfoMetadata.h llvm/lib/BinaryFormat/Dwarf.cpp llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp llvm/lib/IR/DebugInfoMetadata.cpp llvm/lib/IR/Verifier.cpp llvm/lib/Transforms/Utils/Local.cpp llvm/test/DebugInfo/salvage-nonconst-binop.ll llvm/unittests/BinaryFormat/DwarfTest.cpp llvm/unittests/IR/MetadataTest.cpp
``````````

</details>


The following files introduce new uses of undef:
 - llvm/test/DebugInfo/X86/di-expression-symbolic-branch-sdag-salvage.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/210850