CodeGenSchedule: Use resize instead of copying a vector

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183465 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/CodeGenSchedule.cpp b/utils/TableGen/CodeGenSchedule.cpp
index 53b72d0..da16852 100644
--- a/utils/TableGen/CodeGenSchedule.cpp
+++ b/utils/TableGen/CodeGenSchedule.cpp
@@ -1173,8 +1173,8 @@
     // Make N-1 copies of this transition's last sequence.
     for (unsigned i = 1, e = SelectedRWs.size(); i != e; ++i) {
       // Create a temporary copy the vector could reallocate.
-      SmallVector<unsigned, 4> Tmp = RWSequences[OperIdx];
-      RWSequences.push_back(Tmp);
+      RWSequences.reserve(RWSequences.size() + 1);
+      RWSequences.push_back(RWSequences[OperIdx]);
     }
     // Push each of the N elements of the SelectedRWs onto a copy of the last
     // sequence (split the current operand into N operands).