[llvm] SCEV: return std::nullopt for invalid TC (NFC) (PR #94162)

[Ramkumar Ramachandra via llvm-commits]

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@@ -6463,7 +6463,7 @@ getRangeForUnknownRecurrence(const SCEVUnknown *U) {
     // TODO: Handle the power function forms some day.
     return FullSet;
 
-  unsigned TC = getSmallConstantMaxTripCount(L);
+  std::optional<unsigned> TC = getSmallConstantMaxTripCount(L);
   if (!TC || TC >= BitWidth)
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artagnon wrote:

See std::optional<T>::operator>=.

https://github.com/llvm/llvm-project/pull/94162