[llvm] [VPlan] Account for dead FOR splice simplification in cost model (PR #131486)

[Florian Hahn via llvm-commits]

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@@ -7467,6 +7467,16 @@ static bool planContainsAdditionalSimplifications(VPlan &Plan,
         }
         continue;
       }
+      // If a FOR's splice wasn't used it will have been removed, so the VPlan
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fhahn wrote:

nit: might be slightly more compact
```suggestion
      // Unused FOR splices are removed by VPlan transforms, so the VPlan-based cost
```

https://github.com/llvm/llvm-project/pull/131486