Optimize BitVector::all().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183521 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/ADT/BitVector.h b/include/llvm/ADT/BitVector.h
index 3789db4..8f512f5 100644
--- a/include/llvm/ADT/BitVector.h
+++ b/include/llvm/ADT/BitVector.h
@@ -138,8 +138,16 @@
/// 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.
diff --git a/unittests/ADT/BitVectorTest.cpp b/unittests/ADT/BitVectorTest.cpp
index dc298a8..f97be22 100644
--- a/unittests/ADT/BitVectorTest.cpp
+++ b/unittests/ADT/BitVectorTest.cpp
@@ -141,6 +141,14 @@
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());