From c8eb88e7448cb88d2edf31806a04ae9d44d6a66a Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Fri, 10 Apr 2015 12:46:44 +0000
Subject: [PATCH] Microoptimize DenseMap::clear.

Cache NumEntries locally, it's only used in an assert and using the member
variable prevents the compiler from eliminating the tombstone check for types
with trivial destructors. No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234589 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/ADT/DenseMap.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/llvm/ADT/DenseMap.h b/include/llvm/ADT/DenseMap.h
index 7bfa8b22f7a..9c2365af6eb 100644
--- a/include/llvm/ADT/DenseMap.h
+++ b/include/llvm/ADT/DenseMap.h
@@ -100,16 +100,18 @@ public:
     }
 
     const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
+    unsigned NumEntries = getNumEntries();
     for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
       if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
         if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
           P->getSecond().~ValueT();
-          decrementNumEntries();
+          --NumEntries;
         }
         P->getFirst() = EmptyKey;
       }
     }
-    assert(getNumEntries() == 0 && "Node count imbalance!");
+    assert(NumEntries == 0 && "Node count imbalance!");
+    setNumEntries(0);
     setNumTombstones(0);
   }
 
@@ -257,7 +259,7 @@ public:
   const void *getPointerIntoBucketsArray() const { return getBuckets(); }
 
 protected:
-  DenseMapBase() {}
+  DenseMapBase() = default;
 
   void destroyAll() {
     if (getNumBuckets() == 0) // Nothing to do.