[llvm] [LoopPeel] Fix BFI when peeling last iteration without guard (PR #168250)

[Mircea Trofin via llvm-commits]

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@@ -71,6 +73,7 @@ class BranchProbability {
 
   uint32_t getNumerator() const { return N; }
   static uint32_t getDenominator() { return D; }
+  double toDouble() const { return double(N) / D; }
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mtrofin wrote:

nit: `static_cast<double>(N)`

https://github.com/llvm/llvm-project/pull/168250