[llvm] r183521 - Optimize BitVector::all().

[Benjamin Kramer]

Author: d0k
Date: Fri Jun  7 09:14:38 2013
New Revision: 183521

URL: http://llvm.org/viewvc/llvm-project?rev=183521&view=rev
Log:
Optimize BitVector::all().

Modified:
    llvm/trunk/include/llvm/ADT/BitVector.h
    llvm/trunk/unittests/ADT/BitVectorTest.cpp

Modified: llvm/trunk/include/llvm/ADT/BitVector.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/BitVector.h?rev=183521&r1=183520&r2=183521&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/BitVector.h (original)
+++ llvm/trunk/include/llvm/ADT/BitVector.h Fri Jun  7 09:14:38 2013
@@ -138,8 +138,16 @@ public:
 
   /// all - Returns true if all bits are set.
   bool all() const {
-    // TODO: Optimize this.
-    return count() == size();
+    if (empty())
+      return true;
+
+    for (unsigned i = 0; i < NumBitWords(size()) - 1; ++i)
+      if (Bits[i] != ~0UL)
+        return false;
+
+    // For the last word check that the lower bits are ones. The unused bits are
+    // always zero.
+    return Bits[NumBitWords(size()) - 1] == ~(~0UL << (Size % BITWORD_SIZE));
   }
 
   /// none - Returns true if none of the bits are set.

Modified: llvm/trunk/unittests/ADT/BitVectorTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/BitVectorTest.cpp?rev=183521&r1=183520&r2=183521&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/BitVectorTest.cpp (original)
+++ llvm/trunk/unittests/ADT/BitVectorTest.cpp Fri Jun  7 09:14:38 2013
@@ -141,6 +141,14 @@ TYPED_TEST(BitVectorTest, TrivialOperati
   EXPECT_TRUE(Vec.none());
   EXPECT_FALSE(Vec.empty());
 
+  Vec.flip();
+  EXPECT_EQ(130U, Vec.count());
+  EXPECT_EQ(130U, Vec.size());
+  EXPECT_TRUE(Vec.any());
+  EXPECT_TRUE(Vec.all());
+  EXPECT_FALSE(Vec.none());
+  EXPECT_FALSE(Vec.empty());
+
   Inv = TypeParam().flip();
   EXPECT_EQ(0U, Inv.count());
   EXPECT_EQ(0U, Inv.size());