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

[Sander de Smalen via llvm-commits]

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@@ -97,6 +97,14 @@ bool isUniformAcrossVFsAndUFs(VPValue *V);
 /// Returns the header block of the first, top-level loop, or null if none
 /// exist.
 VPBasicBlock *getFirstLoopHeader(VPlan &Plan, VPDominatorTree &VPDT);
+
+/// Returns the VPValue representing the uncounted exit comparison if all the
+/// recipes needed to form the condition within the vector loop body were
+/// matched.
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sdesmalen-arm wrote:

> [...] if all the recipes needed to form the condition within the vector loop body were matched.

This isn't really saying much, do you mean to say:

> Returns the VPValue representing the uncounted exit comparison for a restricted set of conditions that are considered safe to calculate for the next vector iteration.

? If so, then I'd rather you write that explicitly.

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