[LV][NFC] Simplify initialization of MinProfitableTripCount (#113445)

Iteration runtime check confirms whether the trip count is greater than
VFxUF at least. Therefore, there is no need to adjust the
MinProfitableTripCount to VF if it is zero.
Retaining the original MinProfitableTripCount information is also
beneficial for supporting more profitable runtime checks in the future.

Author: Mel-Chen

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -470,18 +470,14 @@ class InnerLoopVectorizer {
                       ProfileSummaryInfo *PSI, GeneratedRTChecks &RTChecks,
                       VPlan &Plan)
       : OrigLoop(OrigLoop), PSE(PSE), LI(LI), DT(DT), TLI(TLI), TTI(TTI),
-        AC(AC), ORE(ORE), VF(VecWidth), UF(UnrollFactor),
+        AC(AC), ORE(ORE), VF(VecWidth),
+        MinProfitableTripCount(MinProfitableTripCount), UF(UnrollFactor),
         Builder(PSE.getSE()->getContext()), Legal(LVL), Cost(CM), BFI(BFI),
         PSI(PSI), RTChecks(RTChecks), Plan(Plan) {
     // Query this against the original loop and save it here because the profile
     // of the original loop header may change as the transformation happens.
     OptForSizeBasedOnProfile = llvm::shouldOptimizeForSize(
         OrigLoop->getHeader(), PSI, BFI, PGSOQueryType::IRPass);
-
-    if (MinProfitableTripCount.isZero())
-      this->MinProfitableTripCount = VecWidth;
-    else
-      this->MinProfitableTripCount = MinProfitableTripCount;
   }
 
   virtual ~InnerLoopVectorizer() = default;