[llvm] [LoopInterchange] Drop nuw/nsw flags from reduction ops when interchanging (PR #148612)

[Nikita Popov via llvm-commits]

================
@@ -405,6 +409,11 @@ class LoopInterchangeLegality {
 
   /// Set of inner loop induction PHIs
   SmallVector<PHINode *, 8> InnerLoopInductions;
+
+  /// Hold instructions that have nuw/nsw flags and involved in reductions,
+  /// like integer addition/multiplication. Those flags must be dropped when
+  /// exchanging the loops.
----------------
nikic wrote:

```suggestion
  /// interchanging the loops.
```

https://github.com/llvm/llvm-project/pull/148612