<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/149616>149616</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [LLVM][LoongArch] `X86SnippetRepetitorTest.Loop` test fails
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          wegank
      </td>
    </tr>
</table>

<pre>
    On a Loongson 3C6000 machine with a NixOS installation, `X86SnippetRepetitorTest.Loop` test consistently fails when compiling LLVM 19/20. The failure is currently mitigated downstream by https://github.com/loongson-community/nixpkgs/commit/c860c2b769ea3415d073ca2830585f2ee4d39413 and the superseding https://github.com/NixOS/nixpkgs/pull/426088.

Attached is the relevant error log.

```shell
FAIL: LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/21/35 (57237 of 58466)
******************** TEST 'LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/21/35' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/build/llvm-src-20.1.6/llvm/build/unittests/tools/llvm-exegesis/./LLVMExegesisTests-LLVM-Unit-18270-21-35.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=35 GTEST_SHARD_INDEX=21 /build/llvm-src-20.1.6/llvm/build/unittests/tools/llvm-exegesis/./LLVMExegesisTests
--

Script:
--
/build/llvm-src-20.1.6/llvm/build/unittests/tools/llvm-exegesis/./LLVMExegesisTests --gtest_filter=X86SnippetRepetitorTest.Loop
--
/build/llvm-src-20.1.6/llvm/unittests/tools/llvm-exegesis/X86/SnippetRepetitorTest.cpp:104: Failure
Value of: LoopBlock.liveins()
Expected: has 2 elements and there exists some permutation of elements such that:
 - element #0 is an object whose given field is equal to 22, and
 - element #1 is an object whose given field is equal to 0
  Actual: 16-byte object <50-86 E4-23 01-00 00-00 70-86 E4-23 01-00 00-00>, where the following matchers don't match any elements:
matcher #1: is an object whose given field is equal to 0
and where the following elements don't match any matchers:
element #0: 16-byte object <77-00 00-00 01-00 00-00 FF-FF FF-FF FF-FF FF-FF>


/build/llvm-src-20.1.6/llvm/unittests/tools/llvm-exegesis/X86/SnippetRepetitorTest.cpp:104
Value of: LoopBlock.liveins()
Expected: has 2 elements and there exists some permutation of elements such that:
 - element #0 is an object whose given field is equal to 22, and
 - element #1 is an object whose given field is equal to 0
  Actual: 16-byte object <50-86 E4-23 01-00 00-00 70-86 E4-23 01-00 00-00>, where the following matchers don't match any elements:
matcher #1: is an object whose given field is equal to 0
and where the following elements don't match any matchers:
element #0: 16-byte object <77-00 00-00 01-00 00-00 FF-FF FF-FF FF-FF FF-FF>



********************
```
</pre>
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