Revert "Add llvm::enumerate() to STLExtras."

This reverts commit r282804 as it seems to use some C++ features
that not all compilers support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282809 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Zachary Turner

include/llvm/ADT/STLExtras.h

@@ -626,73 +626,6 @@ template <typename T> struct deref {
   }
 };
 
-namespace detail {
-template <typename I, typename V> class enumerator_impl {
-public:
-  template <typename V> struct result_pair {
-    result_pair(std::size_t Index, V Value) : Index(Index), Value(Value) {}
-
-    const std::size_t Index;
-    V Value;
-  };
-
-  template <typename I, typename V> struct iterator {
-    iterator(I Iter, std::size_t Index) : Iter(Iter), Index(Index) {}
-
-    result_pair<const V> operator*() const {
-      return result_pair<const V>(Index, *Iter);
-    }
-    result_pair<V> operator*() { return result_pair<V>(Index, *Iter); }
-
-    iterator &operator++() {
-      ++Iter;
-      ++Index;
-      return *this;
-    }
-
-    bool operator!=(const iterator &RHS) const { return Iter != RHS.Iter; }
-
-  private:
-    I Iter;
-    std::size_t Index;
-  };
-
-  enumerator_impl(I Begin, I End)
-      : Begin(std::move(Begin)), End(std::move(End)) {}
-
-  iterator<I, V> begin() { return iterator<I, V>(Begin, 0); }
-  iterator<I, V> end() { return iterator<I, V>(End, std::size_t(-1)); }
-
-  iterator<I, V> begin() const { return iterator<I, V>(Begin, 0); }
-  iterator<I, V> end() const { return iterator<I, V>(End, std::size_t(-1)); }
-
-private:
-  I Begin;
-  I End;
-};
-}
-
-/// Given an input range, returns a new range whose values are are pair (A,B)
-/// such that A is the 0-based index of the item in the sequence, and B is
-/// the value from the original sequence.  Example:
-///
-/// std::vector<char> Items = {'A', 'B', 'C', 'D'};
-/// for (auto X : enumerate(Items)) {
-///   printf("Item %d - %c\n", X.Item, X.Value);
-/// }
-///
-/// Output:
-///   Item 0 - A
-///   Item 1 - B
-///   Item 2 - C
-///   Item 3 - D
-///
-template <typename R> auto enumerate(R &&Range) {
-  typedef decltype(std::begin(Range)) I;
-  typedef decltype(*std::begin(Range)) V;
-  return detail::enumerator_impl<I, V>(std::begin(Range), std::end(Range));
-}
-
 } // End llvm namespace
 
 #endif

unittests/ADT/STLExtrasTest.cpp

@@ -10,8 +10,6 @@
 #include "llvm/ADT/STLExtras.h"
 #include "gtest/gtest.h"
 
-#include <vector>
-
 using namespace llvm;
 
 namespace {
@@ -39,51 +37,4 @@ TEST(STLExtrasTest, Rank) {
   EXPECT_EQ(4, f(rank<6>()));
 }
 
-TEST(STLExtrasTest, Enumerate) {
-  std::vector<char> foo = {'a', 'b', 'c'};
-
-  std::vector<std::pair<std::size_t, char>> results;
-
-  for (auto X : llvm::enumerate(foo)) {
-    results.push_back(std::make_pair(X.Index, X.Value));
-  }
-  ASSERT_EQ(3, results.size());
-  EXPECT_EQ(0, results[0].first);
-  EXPECT_EQ('a', results[0].second);
-  EXPECT_EQ(1, results[1].first);
-  EXPECT_EQ('b', results[1].second);
-  EXPECT_EQ(2, results[2].first);
-  EXPECT_EQ('c', results[2].second);
-
-  results.clear();
-  const std::vector<int> bar = {'1', '2', '3'};
-  for (auto X : llvm::enumerate(bar)) {
-    results.push_back(std::make_pair(X.Index, X.Value));
-  }
-  EXPECT_EQ(0, results[0].first);
-  EXPECT_EQ('1', results[0].second);
-  EXPECT_EQ(1, results[1].first);
-  EXPECT_EQ('2', results[1].second);
-  EXPECT_EQ(2, results[2].first);
-  EXPECT_EQ('3', results[2].second);
-
-  results.clear();
-  const std::vector<int> baz;
-  for (auto X : llvm::enumerate(baz)) {
-    results.push_back(std::make_pair(X.Index, X.Value));
-  }
-  EXPECT_TRUE(baz.empty());
-}
-
-TEST(STLExtrasTest, EnumerateModify) {
-  std::vector<char> foo = {'a', 'b', 'c'};
-
-  for (auto X : llvm::enumerate(foo)) {
-    ++X.Value;
-  }
-
-  EXPECT_EQ('b', foo[0]);
-  EXPECT_EQ('c', foo[1]);
-  EXPECT_EQ('d', foo[2]);
-}
 }