From 4a5129c700a76bf5c4b7f2aa9c362496fb6d8bd6 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 15 Dec 2009 08:34:01 +0000
Subject: [PATCH] a few improvements: 1. Use std::equal instead of reinventing
 it. 2. don't run dtors in destroy_range if element is pod-like. 3. Use
 isPodLike to decide between memcpy/uninitialized_copy    instead of is_class.
  isPodLike is more generous in some cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91427 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/ADT/SmallVector.h | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
index 69c25d0d962..b16649e23c9 100644
--- a/include/llvm/ADT/SmallVector.h
+++ b/include/llvm/ADT/SmallVector.h
@@ -402,11 +402,7 @@ public:
 
   bool operator==(const SmallVectorImpl &RHS) const {
     if (size() != RHS.size()) return false;
-    for (const T *This = begin(), *That = RHS.begin(), *E = end();
-         This != E; ++This, ++That)
-      if (*This != *That)
-        return false;
-    return true;
+    return std::equal(begin(), end(), RHS.begin());
   }
   bool operator!=(const SmallVectorImpl &RHS) const { return !(*this == RHS); }
 
@@ -440,7 +436,9 @@ private:
   }
 
   void destroy_range(T *S, T *E) {
-    // TODO: POD
+    // No need to do a destroy loop for POD's.
+    if (isPodLike<T>::value) return;
+    
     while (S != E) {
       --E;
       E->~T();
@@ -459,11 +457,11 @@ void SmallVectorImpl<T>::grow(size_t MinSize) {
   T *NewElts = static_cast<T*>(operator new(NewCapacity*sizeof(T)));
 
   // Copy the elements over.
-  if (is_class<T>::value)
-    std::uninitialized_copy(begin(), end(), NewElts);
-  else
-    // Use memcpy for PODs (std::uninitialized_copy optimizes to memmove).
+  if (isPodLike<T>::value)
+    // Use memcpy for PODs: std::uninitialized_copy optimizes to memmove.
     memcpy(NewElts, begin(), CurSize * sizeof(T));
+  else
+    std::uninitialized_copy(begin(), end(), NewElts);
 
   // Destroy the original elements.
   destroy_range(begin(), end());