[llvm] r288647 - ListInit::convertInitializerTo: avoid foldingset lookup if nothing changed

[Matthias Braun via llvm-commits]

Author: matze
Date: Mon Dec  5 00:41:47 2016
New Revision: 288647

URL: http://llvm.org/viewvc/llvm-project?rev=288647&view=rev
Log:
ListInit::convertInitializerTo: avoid foldingset lookup if nothing changed

Modified:
    llvm/trunk/lib/TableGen/Record.cpp

Modified: llvm/trunk/lib/TableGen/Record.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/TableGen/Record.cpp?rev=288647&r1=288646&r2=288647&view=diff
==============================================================================
--- llvm/trunk/lib/TableGen/Record.cpp (original)
+++ llvm/trunk/lib/TableGen/Record.cpp Mon Dec  5 00:41:47 2016
@@ -533,19 +533,28 @@ void ListInit::Profile(FoldingSetNodeID
 }
 
 Init *ListInit::convertInitializerTo(RecTy *Ty) const {
+  if (getType() == Ty)
+    return const_cast<ListInit*>(this);
+
   if (auto *LRT = dyn_cast<ListRecTy>(Ty)) {
     std::vector<Init*> Elements;
+    Elements.reserve(getValues().size());
 
     // Verify that all of the elements of the list are subclasses of the
     // appropriate class!
+    bool Changed = false;
+    RecTy *ElementType = LRT->getElementType();
     for (Init *I : getValues())
-      if (Init *CI = I->convertInitializerTo(LRT->getElementType()))
+      if (Init *CI = I->convertInitializerTo(ElementType)) {
         Elements.push_back(CI);
-      else
+        if (CI != I)
+          Changed = true;
+	  } else
         return nullptr;
 
-    if (isa<ListRecTy>(getType()))
-      return ListInit::get(Elements, Ty);
+    if (!Changed)
+      return const_cast<ListInit*>(this);
+    return ListInit::get(Elements, Ty);
   }
 
   return nullptr;