Add range-based set()/reset() to BitVector. These allow fast setting/resetting of ranges of bits, particularly useful when dealing with very large BitVector's.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165984 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 30 insertions, 0 deletions

diff --git a/include/llvm/ADT/SmallBitVector.h b/include/llvm/ADT/SmallBitVector.h
index 7a645e0c72..fba1d12542 100644
--- a/include/llvm/ADT/SmallBitVector.h
+++ b/include/llvm/ADT/SmallBitVector.h
@@ -300,6 +300,21 @@ public:
     return *this;
   }
 
+  /// set - Efficiently set a range of bits in [I, E)
+  SmallBitVector &set(unsigned I, unsigned E) {
+    assert(I <= E && "Attempted to set backwards range!");
+    assert(E <= size() && "Attempted to set out-of-bounds range!");
+    if (I == E) return *this;
+    if (isSmall()) {
+      uintptr_t EMask = 1 << E;
+      uintptr_t IMask = 1 << I;
+      uintptr_t Mask = EMask - IMask;
+      setSmallBits(getSmallBits() | Mask);
+    } else
+      getPointer()->set(I, E);
+    return *this;
+  }
+
   SmallBitVector &reset() {
     if (isSmall())
       setSmallBits(0);
@@ -316,6 +331,21 @@ public:
     return *this;
   }
 
+  /// reset - Efficiently reset a range of bits in [I, E)
+  SmallBitVector &reset(unsigned I, unsigned E) {
+    assert(I <= E && "Attempted to reset backwards range!");
+    assert(E <= size() && "Attempted to reset out-of-bounds range!");
+    if (I == E) return *this;
+    if (isSmall()) {
+      uintptr_t EMask = 1 << E;
+      uintptr_t IMask = 1 << I;
+      uintptr_t Mask = EMask - IMask;
+      setSmallBits(getSmallBits() & ~Mask);
+    } else
+      getPointer()->reset(I, E);
+    return *this;
+  }
+
   SmallBitVector &flip() {
     if (isSmall())
       setSmallBits(~getSmallBits());