From 294e3ec1ba1c1ebd486998c9a2f191bf5f1eab82 Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Fri, 17 Jul 2020 10:42:23 -0700
Subject: [PATCH] [llvm] Add contains(KeyType) -> bool methods to SmallSet

Matches C++20 API addition.

Differential Revision: https://reviews.llvm.org/D83449
---
 include/llvm/ADT/SmallSet.h    |  7 +++++++
 unittests/ADT/SmallSetTest.cpp | 25 +++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/llvm/ADT/SmallSet.h b/include/llvm/ADT/SmallSet.h
index a03fa7dd842..0600e528ee6 100644
--- a/include/llvm/ADT/SmallSet.h
+++ b/include/llvm/ADT/SmallSet.h
@@ -232,6 +232,13 @@ public:
     return {Set.end()};
   }
 
+  /// Check if the SmallSet contains the given element.
+  bool contains(const T &V) const {
+    if (isSmall())
+      return vfind(V) != Vector.end();
+    return Set.find(V) != Set.end();
+  }
+
 private:
   bool isSmall() const { return Set.empty(); }
 
diff --git a/unittests/ADT/SmallSetTest.cpp b/unittests/ADT/SmallSetTest.cpp
index 06682ce823d..26cab828c78 100644
--- a/unittests/ADT/SmallSetTest.cpp
+++ b/unittests/ADT/SmallSetTest.cpp
@@ -167,3 +167,28 @@ TEST(SmallSetTest, EqualityComparisonTest) {
   EXPECT_NE(s1small, s4large);
   EXPECT_NE(s4large, s3large);
 }
+
+TEST(SmallSetTest, Contains) {
+  SmallSet<int, 2> Set;
+  EXPECT_FALSE(Set.contains(0));
+  EXPECT_FALSE(Set.contains(1));
+
+  Set.insert(0);
+  Set.insert(1);
+  EXPECT_TRUE(Set.contains(0));
+  EXPECT_TRUE(Set.contains(1));
+
+  Set.insert(1);
+  EXPECT_TRUE(Set.contains(0));
+  EXPECT_TRUE(Set.contains(1));
+
+  Set.erase(1);
+  EXPECT_TRUE(Set.contains(0));
+  EXPECT_FALSE(Set.contains(1));
+
+  Set.insert(1);
+  Set.insert(2);
+  EXPECT_TRUE(Set.contains(0));
+  EXPECT_TRUE(Set.contains(1));
+  EXPECT_TRUE(Set.contains(2));
+}