[llvm] [TableGen] Use vector constructor instead of calling append or emplace_back on an empty vector. NFC (PR #123442)

[Craig Topper via llvm-commits]

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@@ -1711,24 +1711,23 @@ void CodeGenSchedModels::inferFromRW(ArrayRef<unsigned> OperWrites,
              dbgs() << ") ");
   // Create a seed transition with an empty PredTerm and the expanded sequences
   // of SchedWrites for the current SchedClass.
-  std::vector<PredTransition> LastTransitions;
-  LastTransitions.emplace_back();
+  std::vector<PredTransition> LastTransitions(1);
 
   for (unsigned WriteIdx : OperWrites) {
     IdxVec WriteSeq;
     expandRWSequence(WriteIdx, WriteSeq, /*IsRead=*/false);
-    LastTransitions[0].WriteSequences.emplace_back();
-    SmallVectorImpl<unsigned> &Seq = LastTransitions[0].WriteSequences.back();
-    Seq.append(WriteSeq.begin(), WriteSeq.end());
+    SmallVectorImpl<unsigned> &Seq =
+        LastTransitions[0].WriteSequences.emplace_back(WriteSeq.begin(),
+                                                       WriteSeq.end());
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topperc wrote:

Good idea, thanks.

https://github.com/llvm/llvm-project/pull/123442