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.

llvm-svn: 238601

clang/lib/Sema/SemaCodeComplete.cpp

@@ -1018,9 +1018,7 @@ void ResultBuilder::AddResult(Result R) {
 }
 
 /// \brief Enter into a new scope.
-void ResultBuilder::EnterNewScope() {
-  ShadowMaps.push_back(ShadowMap());
-}
+void ResultBuilder::EnterNewScope() { ShadowMaps.emplace_back(); }
 
 /// \brief Exit from the current scope.
 void ResultBuilder::ExitScope() {