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: 238602

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -63,9 +63,7 @@ public:
   // vector compatibility methods
   unsigned size() const { return ValuePtrs.size(); }
   void resize(unsigned N) { ValuePtrs.resize(N); }
-  void push_back(Value *V) {
-    ValuePtrs.push_back(V);
-  }
+  void push_back(Value *V) { ValuePtrs.emplace_back(V); }
 
   void clear() {
     assert(ResolveConstants.empty() && "Constants not resolved?");