[llvm] [LV] Allow for vectorizing parallel def-use chains (PR #225405)

[John Brawn via llvm-commits]

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@@ -354,9 +354,16 @@ static RecurrenceDescriptor getMinMaxRecurrence(PHINode *Phi, Loop *TheLoop,
     return !Chain.contains(U) && TheLoop->contains(U) &&
            GetMinMaxRK(U, A, B) == RecurKind::None;
   });
+
+  // If the backedge value has more than one use we should consider whether
+  // these are actually uses inside the loop.
+  bool BackedgeNumUsesInLoop = count_if(BackedgeValue->users(), [&](User *U) {
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john-brawn-arm wrote:

This should be an integer type. Using a bool here means we optimize when there's at least one use in the loop, though this not causing any test failures implies we're also missing a test of there being more than one use in the loop.

https://github.com/llvm/llvm-project/pull/225405