[llvm] [Exegesis] CPU selection, when native arch and target mismatch (PR #131014)

[Min-Yih Hsu via llvm-commits]

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@@ -479,6 +480,12 @@ void benchmarkMain() {
 #endif
   }
 
+  // case for cross generating, when native arch and target mismatch
+  if ((Triple(sys::getProcessTriple()).getArch() !=
+       Triple(TripleName).getArch()) &&
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mshockwave wrote:

llvm-exegesis allows `-mtriple` to be empty, in which case it uses default target triple. But that (adopting default target triple) will not reflect on `TripleName`, so you might incorrectly showing this error on a X86 machine with `llvm-exegesis -mcpu=native ...`

The adoption of default target triple happens in `LLVMState::Create`, so I would recommend adding a method to LLVMState to retrieve the resolved triple and make the check you proposed here after the creation of LLVMState.

https://github.com/llvm/llvm-project/pull/131014