[llvm] 0986433 - Revert "Fix iterator_adaptor_base/enumerator_iter to allow composition of llvm::enumerate with llvm::make_filter_range"

[Mehdi Amini via llvm-commits]

Author: Mehdi Amini
Date: 2021-11-04T00:14:12Z
New Revision: 0986433401067c72816450e64d73a79f16cc3c5e

URL: https://github.com/llvm/llvm-project/commit/0986433401067c72816450e64d73a79f16cc3c5e
DIFF: https://github.com/llvm/llvm-project/commit/0986433401067c72816450e64d73a79f16cc3c5e.diff

LOG: Revert "Fix iterator_adaptor_base/enumerator_iter to allow composition of llvm::enumerate with llvm::make_filter_range"

This reverts commit ba7a6b314fd14bb2c9ff5d3f4fe2b6525514cada.

Post-commit review showed that the fix implemented wasn't correct, and a
more principled fix is possible.

Added: 
    

Modified: 
    llvm/include/llvm/ADT/STLExtras.h
    llvm/include/llvm/ADT/iterator.h
    llvm/unittests/ADT/IteratorTest.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index a00561760bc0a..68bc656042073 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -1907,7 +1907,8 @@ class enumerator_iter
     : public iterator_facade_base<
           enumerator_iter<R>, std::forward_iterator_tag, result_pair<R>,
           typename std::iterator_traits<IterOfRange<R>>::
diff erence_type,
-          typename std::iterator_traits<IterOfRange<R>>::pointer> {
+          typename std::iterator_traits<IterOfRange<R>>::pointer,
+          typename std::iterator_traits<IterOfRange<R>>::reference> {
   using result_type = result_pair<R>;
 
 public:

diff  --git a/llvm/include/llvm/ADT/iterator.h b/llvm/include/llvm/ADT/iterator.h
index b93aaf39c171b..b9bac9d385c0b 100644
--- a/llvm/include/llvm/ADT/iterator.h
+++ b/llvm/include/llvm/ADT/iterator.h
@@ -296,8 +296,7 @@ class iterator_adaptor_base
     return LHS.I < RHS.I;
   }
 
-  const ReferenceT operator*() const { return *I; }
-  ReferenceT operator*() { return *I; }
+  ReferenceT operator*() const { return *I; }
 };
 
 /// An iterator type that allows iterating over the pointees via some

diff  --git a/llvm/unittests/ADT/IteratorTest.cpp b/llvm/unittests/ADT/IteratorTest.cpp
index f5fa88e7493f8..de74811321a9a 100644
--- a/llvm/unittests/ADT/IteratorTest.cpp
+++ b/llvm/unittests/ADT/IteratorTest.cpp
@@ -178,16 +178,6 @@ TEST(FilterIteratorTest, Lambda) {
   EXPECT_EQ((SmallVector<int, 3>{1, 3, 5}), Actual);
 }
 
-TEST(FilterIteratorTest, Enumerate) {
-  auto IsOdd = [](auto N) { return N.value() % 2 == 1; };
-  int A[] = {0, 1, 2, 3, 4, 5, 6};
-  auto Enumerate = llvm::enumerate(A);
-  SmallVector<int> Actual;
-  for (auto IndexedValue : make_filter_range(Enumerate, IsOdd))
-    Actual.push_back(IndexedValue.value());
-  EXPECT_EQ((SmallVector<int, 3>{1, 3, 5}), Actual);
-}
-
 TEST(FilterIteratorTest, CallableObject) {
   int Counter = 0;
   struct Callable {