[LoopPeel] Support last iteration peeling of min/max intrinsics (#143598)

This isn't terribly useful at the moment because of the step=1
restriction but it should be functionally sound. This is mostly just
making sure the codepaths don't diverge as we make other changes.

1 files changed, 4 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopPeel.cpp b/llvm/lib/Transforms/Utils/LoopPeel.cpp
index f343962..27e70c5 100644
--- a/llvm/lib/Transforms/Utils/LoopPeel.cpp
+++ b/llvm/lib/Transforms/Utils/LoopPeel.cpp
@@ -545,8 +545,11 @@ countToEliminateCompares(Loop &L, unsigned MaxPeelCount, ScalarEvolution &SE,
     const SCEV *IterVal = AddRec->evaluateAtIteration(
         SE.getConstant(AddRec->getType(), NewPeelCount), SE);
     if (!PeelWhilePredicateIsKnown(NewPeelCount, IterVal, BoundSCEV, Step,
-                                   Pred))
+                                   Pred)) {
+      if (shouldPeelLastIteration(L, Pred, AddRec, BoundSCEV, SE, TTI))
+        DesiredPeelCountLast = 1;
       return;
+    }
     DesiredPeelCount = NewPeelCount;
   };