From 2430973fb657eb84dfbacb1e8886d3a29190e0b5 Mon Sep 17 00:00:00 2001
From: Pete Cooper <peter_cooper@apple.com>
Date: Tue, 23 Oct 2012 19:34:36 +0000
Subject: [PATCH] Change DenseMap to use a power of 2 growth if one is given
 instead of the next power of 2.  This was causing DenseMaps to grow 4x
 instead of 2x.  I'll keep an eye on the buildbots as this could impact
 performance

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166493 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/ADT/DenseMap.h | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/include/llvm/ADT/DenseMap.h b/include/llvm/ADT/DenseMap.h
index 0ae54f42926..ce07f8e9c52 100644
--- a/include/llvm/ADT/DenseMap.h
+++ b/include/llvm/ADT/DenseMap.h
@@ -420,7 +420,7 @@ private:
       NumBuckets = getNumBuckets();
     }
     if (NumBuckets-(NewNumEntries+getNumTombstones()) <= NumBuckets/8) {
-      this->grow(NumBuckets);
+      this->grow(NumBuckets * 2);
       LookupBucketFor(Key, TheBucket);
     }
     assert(TheBucket);
@@ -600,7 +600,8 @@ public:
     unsigned OldNumBuckets = NumBuckets;
     BucketT *OldBuckets = Buckets;
 
-    allocateBuckets(std::max<unsigned>(64, NextPowerOf2(AtLeast)));
+    AtLeast = isPowerOf2_32(AtLeast) ? AtLeast : NextPowerOf2(AtLeast);
+    allocateBuckets(std::max<unsigned>(64, AtLeast));
     assert(Buckets);
     if (!OldBuckets) {
       this->BaseT::initEmpty();
@@ -826,8 +827,10 @@ public:
   }
 
   void grow(unsigned AtLeast) {
-    if (AtLeast >= InlineBuckets)
-      AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast));
+    if (AtLeast >= InlineBuckets) {
+      AtLeast = isPowerOf2_32(AtLeast) ? AtLeast : NextPowerOf2(AtLeast);
+      AtLeast = std::max<unsigned>(64, AtLeast);
+    }
 
     if (Small) {
       if (AtLeast < InlineBuckets)