From 9c24ff3da79c020100a4693db7070db6dc1bfeaf Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 30 Jun 2008 21:45:13 +0000
Subject: [PATCH] Make SmallVector's grow use memcpy in common cases instead of
 std::uninitialized_copy, which uses memmove.

llvm-svn: 52928
---
 llvm/include/llvm/ADT/SmallVector.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/ADT/SmallVector.h b/llvm/include/llvm/ADT/SmallVector.h
index 3d1640cb5710..daf6ee53fcf6 100644
--- a/llvm/include/llvm/ADT/SmallVector.h
+++ b/llvm/include/llvm/ADT/SmallVector.h
@@ -15,6 +15,7 @@
 #define LLVM_ADT_SMALLVECTOR_H
 
 #include "llvm/ADT/iterator.h"
+#include "llvm/Support/type_traits.h"
 #include <algorithm>
 #include <memory>
 
@@ -349,7 +350,11 @@ void SmallVectorImpl<T>::grow(size_t MinSize) {
   T *NewElts = static_cast<T*>(operator new(NewCapacity*sizeof(T)));
   
   // Copy the elements over.
-  std::uninitialized_copy(Begin, End, NewElts);
+  if (is_class<T>::value)
+    std::uninitialized_copy(Begin, End, NewElts);
+  else
+    // Use memcpy for PODs (std::uninitialized_copy optimizes to memmove).
+    memcpy(NewElts, Begin, CurSize * sizeof(T));
   
   // Destroy the original elements.
   destroy_range(Begin, End);