[llvm] [LoopRotation] Enable LoopRotation with -Oz if header folds (PR #72842)

[Daniil Fukalov via llvm-commits]

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@@ -365,6 +365,65 @@ static void updateBranchWeights(BranchInst &PreHeaderBI, BranchInst &LoopBI,
   }
 }
 
+// Check if duplicating the header to the preheader will fold all duplicated
+// instructions, terminating with an unconditional jump. So No code duplication
+// would be necessary.
+static bool canRotateWithoutDuplication(Loop *L, llvm::LoopInfo *LI,
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dfukalov wrote:

It seems `LI` is not used.

https://github.com/llvm/llvm-project/pull/72842