[clang] [llvm] [X86] Add ACE v1 (AI Compute Extensions) support (PR #208408)

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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 clang/lib/Headers/acev1intrin.h clang/test/CodeGen/X86/ace-api.c clang/test/CodeGen/X86/ace-builtins.c clang/test/CodeGen/X86/ace-inline-asm.c clang/test/CodeGen/X86/acev1.c clang/test/CodeGen/X86/acev1_api.c clang/test/CodeGen/X86/acev1_bsr.c clang/test/CodeGen/X86/acev1_errors.c clang/test/CodeGen/X86/acev1_inline_asm.c clang/test/CodeGen/X86/acev1_mxfp8.c clang/test/CodeGen/X86/acev1_tile_movement.c llvm/test/CodeGen/X86/ACE/ace-intrinsics.ll llvm/test/CodeGen/X86/ACE/acev1-greedy-ra.ll llvm/test/CodeGen/X86/ACE/acev1-outer-product.ll llvm/test/CodeGen/X86/ACE/acev1-tile-basic.ll clang/lib/Basic/Targets/X86.cpp clang/lib/Basic/Targets/X86.h clang/lib/Headers/cpuid.h clang/lib/Headers/immintrin.h clang/lib/Sema/SemaX86.cpp clang/test/CodeGen/attr-target-x86.c clang/test/Preprocessor/x86_target_features.c llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp llvm/lib/Target/X86/MCTargetDesc/X86ATTInstPrinter.cpp llvm/lib/Target/X86/MCTargetDesc/X86ATTInstPrinter.h llvm/lib/Target/X86/MCTargetDesc/X86IntelInstPrinter.cpp llvm/lib/Target/X86/MCTargetDesc/X86IntelInstPrinter.h llvm/lib/Target/X86/X86ExpandPseudo.cpp llvm/lib/Target/X86/X86FastPreTileConfig.cpp llvm/lib/Target/X86/X86FastTileConfig.cpp llvm/lib/Target/X86/X86FrameLowering.cpp llvm/lib/Target/X86/X86ISelDAGToDAG.cpp llvm/lib/Target/X86/X86ISelLowering.cpp llvm/lib/Target/X86/X86InstrInfo.cpp llvm/lib/Target/X86/X86LowerAMXType.cpp llvm/lib/Target/X86/X86LowerTileCopy.cpp llvm/lib/Target/X86/X86MachineFunctionInfo.cpp llvm/lib/Target/X86/X86MachineFunctionInfo.h llvm/lib/Target/X86/X86PreTileConfig.cpp llvm/lib/Target/X86/X86RegisterInfo.cpp llvm/lib/Target/X86/X86TileConfig.cpp llvm/lib/TargetParser/X86TargetParser.cpp llvm/test/CodeGen/X86/ipra-reg-usage.ll llvm/test/TableGen/x86-fold-tables.inc
``````````

</details>


The following files introduce new uses of undef:
 - llvm/lib/Target/X86/X86LowerAMXType.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/208408