C++: Minor optimization

Avoid double map lookup

Change-Id: I5fe6b4a13829275f5a68f794cb820b488f4a5c8c
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/libs/3rdparty/cplusplus/Templates.cpp

@@ -40,8 +40,9 @@ CloneType::CloneType(Clone *clone)
 FullySpecifiedType CloneType::cloneType(const FullySpecifiedType &type, Subst *subst)
 {
     TypeSubstPair typeSubstPair = std::make_pair(type, subst);
-    if (_cache.find(typeSubstPair) != _cache.end())
-        return _cache[typeSubstPair];
+    auto it = _cache.find(typeSubstPair);
+    if (it != _cache.end())
+        return it->second;
 
     std::swap(_subst, subst);
     FullySpecifiedType ty(type);
@@ -186,10 +187,10 @@ Symbol *CloneSymbol::cloneSymbol(Symbol *symbol, Subst *subst)
         return 0;
 
     SymbolSubstPair symbolSubstPair = std::make_pair(symbol, subst);
-    if (_cache.find(symbolSubstPair) != _cache.end()) {
-        Symbol *cachedSymbol = _cache[symbolSubstPair];
-        if (cachedSymbol->enclosingScope() == symbol->enclosingScope())
-            return cachedSymbol;
+    auto it = _cache.find(symbolSubstPair);
+    if (it != _cache.end()) {
+        if (it->second->enclosingScope() == symbol->enclosingScope())
+            return it->second;
     }
 
     Symbol *r = 0;
@@ -410,8 +411,9 @@ const Name *CloneName::cloneName(const Name *name, Subst *subst)
         return 0;
 
     NameSubstPair nameSubstPair = std::make_pair(name, subst);
-    if (_cache.find(nameSubstPair) != _cache.end())
-        return _cache[nameSubstPair];
+    auto it = _cache.find(nameSubstPair);
+    if (it != _cache.end())
+        return it->second;
 
     const Name *r = 0;
     std::swap(_subst, subst);
@@ -545,7 +547,7 @@ Symbol *Clone::instantiate(Template *templ, const FullySpecifiedType *const args
 FullySpecifiedType Subst::apply(const Name *name) const
 {
     if (name) {
-        std::map<const Name *, FullySpecifiedType, Name::Compare>::const_iterator it = _map.find(name);
+        auto it = _map.find(name);
         if (it != _map.end())
             return it->second;
         else if (_previous)