From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Sun, 29 Jan 2012 01:29:22 +0000 (+0000)
Subject: Add a BitVector::reset(BitVector&) method.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=19de016955f744cf2466fadcd28e9bf8847dd260;p=oota-llvm.git

Add a BitVector::reset(BitVector&) method.

The alternative LHS &= ~RHS is way too slow because it creates a
temporary that calls malloc/free.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149187 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/ADT/BitVector.h b/include/llvm/ADT/BitVector.h
index 7d7afc347eb..d5f247bb22c 100644
--- a/include/llvm/ADT/BitVector.h
+++ b/include/llvm/ADT/BitVector.h
@@ -318,6 +318,16 @@ public:
     return *this;
   }
 
+  // reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
+  BitVector &reset(const BitVector &RHS) {
+    unsigned ThisWords = NumBitWords(size());
+    unsigned RHSWords  = NumBitWords(RHS.size());
+    unsigned i;
+    for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
+      Bits[i] &= ~RHS.Bits[i];
+    return *this;
+  }
+
   BitVector &operator|=(const BitVector &RHS) {
     if (size() < RHS.size())
       resize(RHS.size());