[llvm] [LV] Add initial support for partial alias masking (PR #177599)

[Benjamin Maxwell via llvm-commits]

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@@ -278,6 +278,13 @@ struct VPTransformState {
     Iter->second[CacheIdx] = V;
   }
 
+  /// Returns the runtime clamped VF (or nullptr if the VF is not clamped).
+  Value *getRTClampedVF() {
+    if (!ClampedVF)
+      return nullptr;
+    return get(ClampedVF, /*IsScalar=*/true);
+  }
+
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MacDue wrote:

I can look into it. I avoided it's likely to cause a lot of churn (in both VPlan printing and IR tests). 

https://github.com/llvm/llvm-project/pull/177599