[SLP] Exit early if MaxVF < MinVF (NFCI). (#83283)

Exit early if MaxVF < MinVF. In that case, the loop body below will
never get entered. Note that this adjusts the condition from MaxVF <=
MinVF. If MaxVF == MinVF, vectorization may still be feasible (and the
loop below gets entered).

PR: #83283

Author: fhahn

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -14019,10 +14019,11 @@ bool SLPVectorizerPass::vectorizeStores(ArrayRef<StoreInst *> Stores,
       unsigned MinVF = TTI->getStoreMinimumVF(
           R.getMinVF(DL->getTypeSizeInBits(ValueTy)), StoreTy, ValueTy);
 
-      if (MaxVF <= MinVF) {
+      if (MaxVF < MinVF) {
         LLVM_DEBUG(dbgs() << "SLP: Vectorization infeasible as MaxVF (" << MaxVF
-                          << ") <= "
+                          << ") < "
                           << "MinVF (" << MinVF << ")\n");
+        continue;
       }
 
       // FIXME: Is division-by-2 the correct step? Should we assert that the