Remove the expensive BitVector::operator~().

Returning a temporary BitVector is very expensive. If you must, create
the temporary explicitly: Use BitVector(A).flip() instead of ~A.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156768 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/ADT/BitVectorTest.cpp b/unittests/ADT/BitVectorTest.cpp
index 24ce3dd..62aadf6 100644
--- a/unittests/ADT/BitVectorTest.cpp
+++ b/unittests/ADT/BitVectorTest.cpp
@@ -42,7 +42,8 @@
   EXPECT_FALSE(Vec.none());
   EXPECT_FALSE(Vec.empty());
 
-  BitVector Inv = ~Vec;
+  BitVector Inv = Vec;
+  Inv.flip();
   EXPECT_EQ(6U, Inv.count());
   EXPECT_EQ(11U, Inv.size());
   EXPECT_TRUE(Inv.any());
@@ -52,7 +53,7 @@
 
   EXPECT_FALSE(Inv == Vec);
   EXPECT_TRUE(Inv != Vec);
-  Vec = ~Vec;
+  Vec.flip();
   EXPECT_TRUE(Inv == Vec);
   EXPECT_FALSE(Inv != Vec);
 
@@ -131,7 +132,7 @@
   EXPECT_TRUE(Vec.none());
   EXPECT_FALSE(Vec.empty());
 
-  Inv = ~BitVector();
+  Inv = BitVector().flip();
   EXPECT_EQ(0U, Inv.count());
   EXPECT_EQ(0U, Inv.size());
   EXPECT_FALSE(Inv.any());