Replace push_back(Constructor(foo)) with emplace_back(foo) for non-trivial types

If the type isn't trivially moveable emplace can skip a potentially
expensive move. It also saves a couple of characters.


Call sites were found with the ASTMatcher + some semi-automated cleanup.

memberCallExpr(
    argumentCountIs(1), callee(methodDecl(hasName("push_back"))),
    on(hasType(recordDecl(has(namedDecl(hasName("emplace_back")))))),
    hasArgument(0, bindTemporaryExpr(
                       hasType(recordDecl(hasNonTrivialDestructor())),
                       has(constructExpr()))),
    unless(isInTemplateInstantiation()))

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238602 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp

@@ -71,7 +71,7 @@ SUnit *ScheduleDAGSDNodes::newSUnit(SDNode *N) {
   if (!SUnits.empty())
     Addr = &SUnits[0];
 #endif
-  SUnits.push_back(SUnit(N, (unsigned)SUnits.size()));
+  SUnits.emplace_back(N, (unsigned)SUnits.size());
   assert((Addr == nullptr || Addr == &SUnits[0]) &&
          "SUnits std::vector reallocated on the fly!");
   SUnits.back().OrigNode = &SUnits.back();