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/ExecutionEngine/Interpreter/Execution.cpp

@@ -2079,7 +2079,7 @@ void Interpreter::callFunction(Function *F,
           ECStack.back().Caller.arg_size() == ArgVals.size()) &&
          "Incorrect number of arguments passed into function call!");
   // Make a new stack frame... and fill it in.
-  ECStack.push_back(ExecutionContext());
+  ECStack.emplace_back();
   ExecutionContext &StackFrame = ECStack.back();
   StackFrame.CurFunction = F;