[llvm] [LV] Adjust exit recipe detection to run on early vplan (PR #183318)

[Florian Hahn via llvm-commits]

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@@ -472,58 +472,64 @@ unsigned vputils::getVFScaleFactor(VPRecipeBase *R) {
 }
 
 std::optional<VPValue *>
-vputils::getRecipesForUncountableExit(VPlan &Plan,
-                                      SmallVectorImpl<VPRecipeBase *> &Recipes,
-                                      SmallVectorImpl<VPRecipeBase *> &GEPs) {
-  // Given a VPlan like the following (just including the recipes contributing
-  // to loop control exiting here, not the actual work), we're looking to match
-  // the recipes contributing to the uncountable exit condition comparison
-  // (here, vp<%4>) back to either live-ins or the address nodes for the load
-  // used as part of the uncountable exit comparison so that we can copy them
-  // to a preheader and rotate the address in the loop to the next vector
-  // iteration.
+vputils::getRecipesForUncountableExit(SmallVectorImpl<VPInstruction *> &Recipes,
+                                      SmallVectorImpl<VPInstruction *> &GEPs,
+                                      VPBasicBlock *LatchVPBB) {
+  /// Given a plain CFG VPlan loop with countable latch exiting block
----------------
fhahn wrote:

```suggestion
  // Given a plain CFG VPlan loop with countable latch exiting block
```
`///` is usually only needed for doxygen comments

https://github.com/llvm/llvm-project/pull/183318