[ADT] Use `adl_begin`/`end` in `replace`. (#130523)

This is to make sure that ADT helpers consistently use argument
dependent lookup when dealing with input ranges.

This was a part of #87936 but reverted due to buildbot failures.

Also clean up the implementation to adhere to the llvm coding standards.

2 files changed, 20 insertions, 7 deletions

diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index 885b5b037f42..18e73b4a138d 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -2124,7 +2124,7 @@ void append_values(Container &C, Args &&...Values) {
 
 /// Given a sequence container Cont, replace the range [ContIt, ContEnd) with
 /// the range [ValIt, ValEnd) (which is not from the same container).
-template<typename Container, typename RandomAccessIterator>
+template <typename Container, typename RandomAccessIterator>
 void replace(Container &Cont, typename Container::iterator ContIt,
              typename Container::iterator ContEnd, RandomAccessIterator ValIt,
              RandomAccessIterator ValEnd) {
@@ -2132,21 +2132,24 @@ void replace(Container &Cont, typename Container::iterator ContIt,
     if (ValIt == ValEnd) {
       Cont.erase(ContIt, ContEnd);
       return;
-    } else if (ContIt == ContEnd) {
+    }
+    if (ContIt == ContEnd) {
       Cont.insert(ContIt, ValIt, ValEnd);
       return;
     }
-    *ContIt++ = *ValIt++;
+    *ContIt = *ValIt;
+    ++ContIt;
+    ++ValIt;
   }
 }
 
 /// Given a sequence container Cont, replace the range [ContIt, ContEnd) with
 /// the range R.
-template<typename Container, typename Range = std::initializer_list<
-                                 typename Container::value_type>>
+template <typename Container, typename Range = std::initializer_list<
+                                  typename Container::value_type>>
 void replace(Container &Cont, typename Container::iterator ContIt,
-             typename Container::iterator ContEnd, Range R) {
-  replace(Cont, ContIt, ContEnd, R.begin(), R.end());
+             typename Container::iterator ContEnd, Range &&R) {
+  replace(Cont, ContIt, ContEnd, adl_begin(R), adl_end(R));
 }
 
 /// An STL-style algorithm similar to std::for_each that applies a second
diff --git a/llvm/unittests/ADT/STLExtrasTest.cpp b/llvm/unittests/ADT/STLExtrasTest.cpp
index 2b2b4ae9b9e9..ad0149bf99ea 100644
--- a/llvm/unittests/ADT/STLExtrasTest.cpp
+++ b/llvm/unittests/ADT/STLExtrasTest.cpp
@@ -864,6 +864,16 @@ TEST(STLExtrasTest, EarlyIncrementTestCustomPointerIterator) {
   EXPECT_EQ(EIR.end(), I);
 }
 
+TEST(STLExtrasTest, ReplaceADL) {
+  // Make sure that we use the `begin`/`end` functions from `some_namespace`,
+  // using ADL.
+  std::vector<int> Cont = {0, 1, 2, 3, 4, 5};
+  some_namespace::some_struct S;
+  S.data = {42, 43, 44};
+  replace(Cont, Cont.begin() + 2, Cont.begin() + 5, S);
+  EXPECT_THAT(Cont, ElementsAre(0, 1, 42, 43, 44, 5));
+}
+
 TEST(STLExtrasTest, AllEqual) {
   std::vector<int> V;
   EXPECT_TRUE(all_equal(V));