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

diff --git a/include/llvm/ADT/DenseMap.h b/include/llvm/ADT/DenseMap.h
index 7bfa8b22f7a3a40dde86d50ae15276e14e4faa3d..9c2365af6eb81109d8ce5cfccc8cbd3e7fdb6d18 100644 (file)
--- 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.