[llvm] [LV] Add support for partial alias masking with tail folding (PR #182457)

[Benjamin Maxwell via llvm-commits]

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@@ -1499,6 +1565,21 @@ class LoopVectorizationCostModel {
   /// initialized during object construction.
   std::optional<unsigned> VScaleForTuning;
 
+  bool isUniform(Value *V, ElementCount VF) const {
+    // With alias-masking our runtime VF is [2, VF] (and not necessarily a
+    // power-of-two). Something that is uniform for VF may not be for the full
+    // range.
+    assert(PartialAliasMaskingStatus != AliasMaskingStatus::NotDecided);
+    return PartialAliasMaskingStatus == AliasMaskingStatus::Disabled &&
+           Legal->isUniform(V, VF);
+  }
+
+  bool isUniformMemOp(Instruction &I, ElementCount VF) const {
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MacDue wrote:

(added comment) 

https://github.com/llvm/llvm-project/pull/182457