[llvm] [LV][NFC] Clean up tail-folding check for early-exit loops (PR #133931)

[Florian Hahn via llvm-commits]

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@@ -4032,14 +4016,17 @@ LoopVectorizationCostModel::computeMaxVF(ElementCount UserVF, unsigned UserIC) {
   }
 
   auto NoScalarEpilogueNeeded = [this, &UserIC](unsigned MaxVF) {
+    if (TheLoop->getExitingBlock() != TheLoop->getLoopLatch() &&
+        !Legal->hasUncountableEarlyExit())
+      return false;
     unsigned MaxVFtimesIC = UserIC ? MaxVF * UserIC : MaxVF;
     ScalarEvolution *SE = PSE.getSE();
-    // Currently only loops with countable exits are vectorized, but calling
-    // getSymbolicMaxBackedgeTakenCount allows enablement work for loops with
-    // uncountable exits whilst also ensuring the symbolic maximum and known
-    // back-edge taken count remain identical for loops with countable exits.
+    // Calling getSymbolicMaxBackedgeTakenCount enables support for loops
+    // with uncountable exits. For countable loops, the symbolic maximum must
+    // remain identical to the known back-edge taken count.
     const SCEV *BackedgeTakenCount = PSE.getSymbolicMaxBackedgeTakenCount();
-    assert(BackedgeTakenCount == PSE.getBackedgeTakenCount() &&
+    assert((Legal->hasUncountableEarlyExit() ||
+            BackedgeTakenCount == PSE.getBackedgeTakenCount()) &&
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fhahn wrote:

Are those changes still needed? 

https://github.com/llvm/llvm-project/pull/133931