small speedup in the case where a smallvector is default ctor'd from

an empty vector.  This speeds up llc slightly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40983 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
index 876ca27fec72e62d1df8fd00e3ede1896046228c..1c970a55981c471d8a3b7a1d289bd1c32bc6ea34 100644 (file)
--- a/include/llvm/ADT/SmallVector.h
+++ b/include/llvm/ADT/SmallVector.h
@@ -455,7 +455,8 @@ public:
   }
   
   SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(NumTsAvailable) {
-    operator=(RHS);
+    if (!RHS.empty())
+      operator=(RHS);
   }
   
   const SmallVector &operator=(const SmallVector &RHS) {