[llvm] [LV] Compute register usage for interleaving on VPlan. (PR #126437)

[Florian Hahn via llvm-commits]

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@@ -4878,8 +4879,232 @@ void LoopVectorizationCostModel::collectElementTypesForWidening() {
   }
 }
 
+/// Estimate the register usage for \p Plan and vectorization factors in \p VFs.
+/// Returns the register usage for each VF in \p VFs.
+static SmallVector<LoopVectorizationCostModel::RegisterUsage, 8>
+calculateRegisterUsage(VPlan &Plan, ArrayRef<ElementCount> VFs,
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fhahn wrote:

Yep, there's one more use remaining, once that has been migrated (which is what IIUC @SamTebbs33 is planning to do?) it can be removed,.

https://github.com/llvm/llvm-project/pull/126437