add an optimization for the case where the src has no name

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34174 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp
index af753236c1d124f6c183939a529a3681b7e3eb68..30ca5c35b5f1e99b8111afeaa223a40ced9eec3f 100644 (file)
--- a/lib/VMCore/Value.cpp
+++ b/lib/VMCore/Value.cpp
@@ -141,6 +141,12 @@ void Value::setName(const std::string &name) {
 /// takeName - transfer the name from V to this value, setting V's name to
 /// empty.  It is an error to call V->takeName(V). 
 void Value::takeName(Value *V) {
+  if (!V->hasName()) {
+    if (hasName())
+      setName("");
+    return;
+  }
+  
   std::string Name = V->getName();
   V->setName("");
   setName(Name);