do not let the table fill up with tombstones.

llvm-svn: 33973

2 files changed, 7 insertions, 1 deletions

diff --git a/llvm/include/llvm/ADT/SmallPtrSet.h b/llvm/include/llvm/ADT/SmallPtrSet.h
index ed7f4da4e1a..1db2945877a 100644
--- a/llvm/include/llvm/ADT/SmallPtrSet.h
+++ b/llvm/include/llvm/ADT/SmallPtrSet.h
@@ -51,6 +51,7 @@ protected:
   
   // If small, this is # elts allocated consequtively
   unsigned NumElements;
+  unsigned NumTombstones;
   void *SmallArray[1];  // Must be last ivar.
 public:
   SmallPtrSetImpl(unsigned SmallSize) {
@@ -82,6 +83,7 @@ public:
     // Fill the array with empty markers.
     memset(CurArray, -1, CurArraySize*sizeof(void*));
     NumElements = 0;
+    NumTombstones = 0;
   }
   
   /// insert - This returns true if the pointer was new to the set, false if it
diff --git a/llvm/lib/Support/SmallPtrSet.cpp b/llvm/lib/Support/SmallPtrSet.cpp
index 758a952ae42..98d5bc99adc 100644
--- a/llvm/lib/Support/SmallPtrSet.cpp
+++ b/llvm/lib/Support/SmallPtrSet.cpp
@@ -32,7 +32,8 @@ bool SmallPtrSetImpl::insert(void *Ptr) {
   }
   
   // If more than 3/4 of the array is full, grow.
-  if (NumElements*4 >= CurArraySize*3)
+  if (NumElements*4 >= CurArraySize*3 ||
+      CurArraySize-(NumElements+NumTombstones) < CurArraySize/8)
     Grow();
   
   // Okay, we know we have space.  Find a hash bucket.
@@ -40,6 +41,8 @@ bool SmallPtrSetImpl::insert(void *Ptr) {
   if (*Bucket == Ptr) return false; // Already inserted, good.
   
   // Otherwise, insert it!
+  if (*Bucket == getTombstoneMarker())
+    --NumTombstones;
   *Bucket = Ptr;
   ++NumElements;  // Track density.
   return true;
@@ -69,6 +72,7 @@ bool SmallPtrSetImpl::erase(void *Ptr) {
   // Set this as a tombstone.
   *Bucket = getTombstoneMarker();
   --NumElements;
+  ++NumTombstones;
   return true;
 }