[llvm] [SLP] De-duplicate costing of perfect-diamond gather spills (PR #220569)

[Alexey Bataev via llvm-commits]

================
@@ -19068,6 +19144,10 @@ InstructionCost BoUpSLP::getSpillCost() {
       if (Entry->State == TreeEntry::SplitVectorize ||
           (Op->isGather() && allConstant(Op->Scalars)))
         continue;
+
+      // Reset the scan budget for analsysis of each edge.
----------------
alexey-bataev wrote:

```suggestion
      // Reset the scan budget for analysis of each edge.
```

https://github.com/llvm/llvm-project/pull/220569