From: Pete Cooper <peter_cooper@apple.com>
Date: Tue, 23 Oct 2012 19:34:36 +0000 (+0000)
Subject: Change DenseMap to use a power of 2 growth if one is given instead of the next power... 
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=2430973fb657eb84dfbacb1e8886d3a29190e0b5;p=oota-llvm.git

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
---

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)