[llvm] [ADT] Add DenseSet::insert_range (PR #131567)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/131567

This pach adds DenseSet::insert_range, named after
std::map::insert_range from C++23.  The intent is to allow a heavy
operation as the argument like:

  Set.insert_range(Map[Key]);

Without insert_range, we would have to do:

  Set.insert(Map[Key].begin(), Map[Key].end());

or:

  auto &M = Map[Key];
  Set.insert(M.begin(), M.end());

Neither is elegant.


>From 88a4372816dd332b04eecd56b26f00c1a34e8d5a Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 16 Mar 2025 22:25:54 -0700
Subject: [PATCH] [ADT] Add DenseSet::insert_range

This pach adds DenseSet::insert_range, named after
std::map::insert_range from C++23.  The intent is to allow a heavy
operation as the argument like:

  Set.insert_range(Map[Key]);

Without insert_range, we would have to do:

  Set.insert(Map[Key].begin(), Map[Key].end());

or:

  auto &M = Map[Key];
  Set.insert(M.begin(), M.end());

Neither is elegant.
---
 llvm/include/llvm/ADT/DenseSet.h    |  5 +++++
 llvm/unittests/ADT/DenseSetTest.cpp | 11 +++++++++++
 2 files changed, 16 insertions(+)

diff --git a/llvm/include/llvm/ADT/DenseSet.h b/llvm/include/llvm/ADT/DenseSet.h
index a307bd8c9198b..ac766e778df0d 100644
--- a/llvm/include/llvm/ADT/DenseSet.h
+++ b/llvm/include/llvm/ADT/DenseSet.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_ADT_DENSESET_H
 #define LLVM_ADT_DENSESET_H
 
+#include "llvm/ADT/ADL.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/Support/MathExtras.h"
@@ -237,6 +238,10 @@ class DenseSetImpl {
     for (; I != E; ++I)
       insert(*I);
   }
+
+  template <typename Range> void insert_range(Range &&R) {
+    insert(adl_begin(R), adl_end(R));
+  }
 };
 
 /// Equality comparison for DenseSet.
diff --git a/llvm/unittests/ADT/DenseSetTest.cpp b/llvm/unittests/ADT/DenseSetTest.cpp
index f14542eafc251..14cef2ab678f9 100644
--- a/llvm/unittests/ADT/DenseSetTest.cpp
+++ b/llvm/unittests/ADT/DenseSetTest.cpp
@@ -32,6 +32,17 @@ TEST(DenseSetTest, DoubleEntrySetTest) {
   EXPECT_EQ(0u, set.count(2));
 }
 
+TEST(DenseSetTest, InsertRange) {
+  llvm::DenseSet<unsigned> set1;
+  llvm::DenseSet<unsigned> set2;
+  set1.insert(1);
+  set1.insert(2);
+  set1.insert(3);
+  constexpr unsigned Args[] = {3, 1, 2};
+  set2.insert_range(Args);
+  EXPECT_EQ(set1, set2);
+}
+
 struct TestDenseSetInfo {
   static inline unsigned getEmptyKey() { return ~0; }
   static inline unsigned getTombstoneKey() { return ~0U - 1; }