[llvm] CodeGen: Add RegisterClass by HwMode (PR #158269)

[Sergei Barannikov via llvm-commits]

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@@ -144,6 +152,21 @@ class CodeGenTarget {
     return LegalValueTypes;
   }
 
+  /// If \p V is a DefInit that can be interpreted as a RegisterClass (e.g.,
+  /// it's a RegisterOperand, or a direct RegisterClass reference), return the
+  /// Record for that RegisterClass.
+  ///
+  /// AssumeRegClassByHwModeIsDefault is a hack which should be removed. It's
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s-barannikov wrote:

```suggestion
  /// AssumeRegClassByHwModeIsDefault is a hack which should be removed. It
```

https://github.com/llvm/llvm-project/pull/158269