[llvm] [LV] Provide utility routine to find uncounted exit recipes (PR #152530)

[Graham Hunter via llvm-commits]

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@@ -138,3 +138,103 @@ VPBasicBlock *vputils::getFirstLoopHeader(VPlan &Plan, VPDominatorTree &VPDT) {
   });
   return I == DepthFirst.end() ? nullptr : cast<VPBasicBlock>(*I);
 }
+
+std::optional<VPValue *> vputils::getRecipesForUncountedExit(
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huntergr-arm wrote:

It's intended to be called after the vplan has been created and the CFG simplified so there's only one exit. This is currently after the existing uncounted early exit transformation, but that is changed in the transform PR to not create the split.

We probably want to formalize the strategy as state in the VPlan so we know which parts of the transformations to apply.

https://github.com/llvm/llvm-project/pull/152530