[llvm] [LV] Transform to handle exits in the scalar loop (PR #148626)

[Florian Hahn via llvm-commits]

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@@ -4182,6 +4182,14 @@ class VPlan {
   /// VPlan is destroyed.
   SmallVector<VPBlockBase *> CreatedBlocks;
 
+  /// The entry block in a vplan, which may be a check block that needs to
+  /// be wired up in the right place with existing check blocks.
+  std::optional<VPBasicBlock *> EarlyExitPreheader;
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fhahn wrote:

Hm, why do we need to keep track of the early exit preheader? Could you add a vplan printing test so it's easier to see what the VPlan looks like? llvm/test/Transforms/LoopVectorize/uncountable-early-exit-vplan.ll is probably a good place.

https://github.com/llvm/llvm-project/pull/148626