[llvm] [LoopPeel] Implement initial peeling off the last loop iteration. (PR #139551)

[Philip Reames via llvm-commits]

================
@@ -439,6 +496,7 @@ static unsigned countToEliminateCompares(Loop &L, unsigned MaxPeelCount,
     }
 
     DesiredPeelCount = std::max(DesiredPeelCount, NewPeelCount);
+    DesiredPeelCountLast = std::max(DesiredPeelCountLast, NewPeelCount);
   };
 
   auto ComputePeelCountMinMax = [&](MinMaxIntrinsic *MinMax) {
----------------
preames wrote:

As a follow up, you can handle the minmax case too.  

https://github.com/llvm/llvm-project/pull/139551