[llvm] [LoopVectorize] Add support for vectorisation of more early exit loops (PR #88385)

[Graham Hunter via llvm-commits]

================
@@ -2569,7 +2606,10 @@ bool LoopAccessInfo::analyzeLoop(AAResults *AA, LoopInfo *LI,
     LLVM_DEBUG(
         dbgs() << "LAA: A loop annotated parallel, ignore memory dependency "
                << "checks.\n");
-    return true;
+    if (!UncountableExitingBlocks.size())
----------------
huntergr-arm wrote:

```suggestion
    if (UncountableExitingBlocks.empty())
```

https://github.com/llvm/llvm-project/pull/88385