[llvm] [SelectionDAG] Provide context for vector count / type mismatch (PR #175433)

[Nikita Popov via llvm-commits]

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@@ -330,6 +331,21 @@ static void diagnosePossiblyInvalidConstraint(LLVMContext &Ctx, const Value *V,
   return Ctx.emitError(I, ErrMsg);
 }
 
+/// Emit a fatal error if the broken dow registers don't match part type
----------------
nikic wrote:

```suggestion
/// Emit a fatal error if the broken down registers don't match part type
```

https://github.com/llvm/llvm-project/pull/175433