!fixup mention fall back to generic logic if set to false.

Author: fhahn

llvm/include/llvm/Analysis/TargetTransformInfo.h

@@ -624,6 +624,8 @@ class TargetTransformInfo {
     unsigned SCEVExpansionBudget;
     /// Allow runtime unrolling multi-exit loops. Should only be set if the
     /// target determined that multi-exit unrolling is profitable for the loop.
+    /// Fall back to the generic logic to determine whether multi-exit unrolling
+    /// is profitable if set to false.
     bool RuntimeUnrollMultiExit;
   };