Add TinyPtrVector support for general pointer-like things.

In particular, make TinyPtrVector<PtrIntPair<T *, 1>> work. Remove all
unnecessary assumptions that the element type has a formal "null"
representation. The important property to maintain is that
default-constructed element type has the same internal representation
as the default-constructed PointerUnion (all zero bits).

Remove the incorrect recursive behavior from
PointerUnion::isNull. This was never generally correct because it only
recursed over the first type parameter. With variadic templates it's
completely unnecessary.

llvm-svn: 369473
diff --git a/llvm/unittests/ADT/PointerUnionTest.cpp b/llvm/unittests/ADT/PointerUnionTest.cpp
index cd6e980..0a88114 100644
--- a/llvm/unittests/ADT/PointerUnionTest.cpp
+++ b/llvm/unittests/ADT/PointerUnionTest.cpp
@@ -13,14 +13,25 @@
 namespace {
 
 typedef PointerUnion<int *, float *> PU;
+typedef PointerUnion3<int *, float *, long long *> PU3;
+typedef PointerUnion4<int *, float *, long long *, double *> PU4;
 
 struct PointerUnionTest : public testing::Test {
   float f;
   int i;
+  double d;
+  long long l;
 
   PU a, b, c, n;
+  PU3 i3, f3, l3;
+  PU4 i4, f4, l4, d4;
+  PU4 i4null, f4null, l4null, d4null;
 
-  PointerUnionTest() : f(3.14f), i(42), a(&f), b(&i), c(&i), n() {}
+  PointerUnionTest()
+      : f(3.14f), i(42), d(3.14), l(42), a(&f), b(&i), c(&i), n(), i3(&i),
+        f3(&f), l3(&l), i4(&i), f4(&f), l4(&l), d4(&d), i4null((int *)nullptr),
+        f4null((float *)nullptr), l4null((long long *)nullptr),
+        d4null((double *)nullptr) {}
 };
 
 TEST_F(PointerUnionTest, Comparison) {
@@ -32,6 +43,19 @@
   EXPECT_FALSE(b != c);
   EXPECT_TRUE(b != n);
   EXPECT_FALSE(b == n);
+  EXPECT_TRUE(i3 == i3);
+  EXPECT_FALSE(i3 != i3);
+  EXPECT_TRUE(i3 != f3);
+  EXPECT_TRUE(f3 != l3);
+  EXPECT_TRUE(i4 == i4);
+  EXPECT_FALSE(i4 != i4);
+  EXPECT_TRUE(i4 != f4);
+  EXPECT_TRUE(i4 != l4);
+  EXPECT_TRUE(f4 != l4);
+  EXPECT_TRUE(l4 != d4);
+  EXPECT_TRUE(i4null != f4null);
+  EXPECT_TRUE(i4null != l4null);
+  EXPECT_TRUE(i4null != d4null);
 }
 
 TEST_F(PointerUnionTest, Null) {
@@ -51,6 +75,17 @@
   b = nullptr;
   EXPECT_EQ(n, b);
   EXPECT_NE(b, c);
+  EXPECT_FALSE(i3.isNull());
+  EXPECT_FALSE(f3.isNull());
+  EXPECT_FALSE(l3.isNull());
+  EXPECT_FALSE(i4.isNull());
+  EXPECT_FALSE(f4.isNull());
+  EXPECT_FALSE(l4.isNull());
+  EXPECT_FALSE(d4.isNull());
+  EXPECT_TRUE(i4null.isNull());
+  EXPECT_TRUE(f4null.isNull());
+  EXPECT_TRUE(l4null.isNull());
+  EXPECT_TRUE(d4null.isNull());
 }
 
 TEST_F(PointerUnionTest, Is) {
@@ -60,6 +95,17 @@
   EXPECT_FALSE(b.is<float *>());
   EXPECT_TRUE(n.is<int *>());
   EXPECT_FALSE(n.is<float *>());
+  EXPECT_TRUE(i3.is<int *>());
+  EXPECT_TRUE(f3.is<float *>());
+  EXPECT_TRUE(l3.is<long long *>());
+  EXPECT_TRUE(i4.is<int *>());
+  EXPECT_TRUE(f4.is<float *>());
+  EXPECT_TRUE(l4.is<long long *>());
+  EXPECT_TRUE(d4.is<double *>());
+  EXPECT_TRUE(i4null.is<int *>());
+  EXPECT_TRUE(f4null.is<float *>());
+  EXPECT_TRUE(l4null.is<long long *>());
+  EXPECT_TRUE(d4null.is<double *>());
 }
 
 TEST_F(PointerUnionTest, Get) {
@@ -105,4 +151,9 @@
   EXPECT_TRUE(a != PU8(&a0));
 }
 
+TEST_F(PointerUnionTest, GetAddrOfPtr1) {
+  EXPECT_TRUE((void *)b.getAddrOfPtr1() == (void *)&b);
+  EXPECT_TRUE((void *)n.getAddrOfPtr1() == (void *)&n);
+}
+
 } // end anonymous namespace