[llvm] [llvm][CodeGen] avoid repeated interval calculation in window scheduler (PR #132352)

[Matt Arsenault via llvm-commits]

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@@ -60,6 +60,7 @@
 #ifndef LLVM_CODEGEN_MODULOSCHEDULE_H
 #define LLVM_CODEGEN_MODULOSCHEDULE_H
 
+#include "llvm/ADT/SmallSet.h"
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arsenm wrote:

```suggestion
```
Dead include? 

https://github.com/llvm/llvm-project/pull/132352