From 1a81a5ba5e044965db2000d2b2316daccf96b935 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.

llvm-svn: 234589
---
 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.