[llvm] [LoopVectorize] Enable vectorisation of early exit loops with live-outs (PR #120567)

[Graham Hunter via llvm-commits]

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@@ -407,6 +407,11 @@ class LoopVectorizationLegality {
 
   /// Returns the destination of an uncountable early exiting block.
   BasicBlock *getUncountableEarlyExitBlock() const {
+    if (!HasUncountableEarlyExit) {
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huntergr-arm wrote:

Is there a reason to have a separate `HasUncountableEarlyExit` variable instead of just checking whether the list of uncountable exit(ing) blocks isn't empty? It just seems that having a single source of truth is better than repeatedly asserting that they agree.

It may also be better to store pairs of (Exiting,Exit) blocks instead of two separate vectors.

https://github.com/llvm/llvm-project/pull/120567