From 37a9577a729f85647991d0eae1fbed3b854b61ed Mon Sep 17 00:00:00 2001
From: Kostya Serebryany <kcc@google.com>
Date: Thu, 13 Feb 2014 15:45:20 +0000
Subject: [sanitizer] optimize TwoLevelBitVector::intersectsWith, extend tests,
 fix a check

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@201338 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/sanitizer_common/sanitizer_bitvector.h | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

(limited to 'lib/sanitizer_common/sanitizer_bitvector.h')

diff --git a/lib/sanitizer_common/sanitizer_bitvector.h b/lib/sanitizer_common/sanitizer_bitvector.h
index cf7b8ccba..93b99a4ce 100644
--- a/lib/sanitizer_common/sanitizer_bitvector.h
+++ b/lib/sanitizer_common/sanitizer_bitvector.h
@@ -61,6 +61,13 @@ class BasicBitVector {
     return bits_ != old;
   }
 
+  // Do "this &= v" and return whether any bits have been removed.
+  bool setIntersection(const BasicBitVector &v) {
+    basic_int_t old = bits_;
+    bits_ &= v.bits_;
+    return bits_ != old;
+  }
+
   void copyFrom(const BasicBitVector &v) { bits_ = v.bits_; }
 
   // Returns true if 'this' intersects with 'v'.
@@ -180,6 +187,26 @@ class TwoLevelBitVector {
     return res;
   }
 
+  // Do "this &= v" and return whether any bits have been removed.
+  bool setIntersection(const TwoLevelBitVector &v) {
+    bool res = false;
+    for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
+      if (l1_[i0].setIntersection(v.l1_[i0]))
+        res = true;
+      if (!l1_[i0].empty()) {
+        BV t = l1_[i0];
+        while (!t.empty()) {
+          uptr i1 = t.getAndClearFirstOne();
+          if (l2_[i0][i1].setIntersection(v.l2_[i0][i1]))
+            res = true;
+          if (l2_[i0][i1].empty())
+            l1_[i0].clearBit(i1);
+        }
+      }
+    }
+    return res;
+  }
+
   void copyFrom(const TwoLevelBitVector &v) {
     clear();
     setUnion(v);
@@ -189,7 +216,7 @@ class TwoLevelBitVector {
   bool intersectsWith(const TwoLevelBitVector &v) const {
     for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
       BV t = l1_[i0];
-      // FIXME: optimization: t &= v.l1_[i0]
+      t.setIntersection(v.l1_[i0]);
       while (!t.empty()) {
         uptr i1 = t.getAndClearFirstOne();
         if (!v.l1_[i0].getBit(i1)) continue;
-- 
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