[llvm] [LV] Only require a scalar epilogue for interleave groups actually widened as interleave accesses (PR #213904)

[Mel Chen via llvm-commits]

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@@ -1275,6 +1284,15 @@ bool VPlanTransforms::handleEarlyExits(VPlan &Plan, UncountableExitStyle Style,
                                        TheLoop, PSE, DT, AC, Style);
   }
 
+  // A scalar epilogue is required if vectorized loop includes countable early
+  // exits.
+  if (MiddleVPBB->getNumSuccessors() == 2) {
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Mel-Chen wrote:

I'm a bit confused about this question. Just to confirm I understand your point, does having a countable early exit always guarantee that the middle block has exactly two successors?

https://github.com/llvm/llvm-project/pull/213904