Revert "add forward iterator"

This reverts commit a5ebf57f198cd79be132854b036f904c3983341d.

Author: jameshu15869

libc/benchmarks/gpu/LibcGpuBenchmark.cpp

@@ -13,8 +13,8 @@ void Benchmark::add_benchmark(Benchmark *benchmark) {
 }
 
 void Benchmark::run_benchmarks() {
-  for (Benchmark *benchmark : benchmarks)
-    benchmark->run();
+  for (auto it = benchmarks.rbegin(), e = benchmarks.rend(); it != e; ++it)
+    (*it)->run();
 }
 
 BenchmarkResult benchmark(const BenchmarkOptions &options,

libc/src/__support/CPP/array.h

@@ -22,12 +22,10 @@ template <class T, size_t N> struct array {
 
   T Data[N];
   using value_type = T;
-  using pointer_type = T *;
-  using iterator = cpp::iterator<pointer_type>;
-  using const_pointer_type = const T *;
-  using const_iterator = cpp::iterator<const_pointer_type>;
-  using reverse_iterator = cpp::reverse_iterator<pointer_type>;
-  using const_reverse_iterator = cpp::reverse_iterator<const_pointer_type>;
+  using iterator = T *;
+  using const_iterator = const T *;
+  using reverse_iterator = cpp::reverse_iterator<iterator>;
+  using const_reverse_iterator = cpp::reverse_iterator<const_iterator>;
 
   LIBC_INLINE constexpr T *data() { return Data; }
   LIBC_INLINE constexpr const T *data() const { return Data; }
@@ -48,16 +46,12 @@ template <class T, size_t N> struct array {
 
   LIBC_INLINE constexpr bool empty() const { return N == 0; }
 
-  LIBC_INLINE constexpr iterator begin() { return iterator{Data}; }
-  LIBC_INLINE constexpr const_iterator begin() const {
-    return const_iterator{Data};
-  }
+  LIBC_INLINE constexpr iterator begin() { return Data; }
+  LIBC_INLINE constexpr const_iterator begin() const { return Data; }
   LIBC_INLINE constexpr const_iterator cbegin() const { return begin(); }
 
-  LIBC_INLINE constexpr iterator end() { return iterator{Data + N}; }
-  LIBC_INLINE constexpr const_iterator end() const {
-    return const_iterator{Data + N};
-  }
+  LIBC_INLINE constexpr iterator end() { return Data + N; }
+  LIBC_INLINE constexpr const_iterator end() const { return Data + N; }
   LIBC_INLINE constexpr const_iterator cend() const { return end(); }
 
   LIBC_INLINE constexpr reverse_iterator rbegin() {
@@ -71,10 +65,10 @@ template <class T, size_t N> struct array {
   }
 
   LIBC_INLINE constexpr reverse_iterator rend() {
-    return reverse_iterator{Data};
+    return reverse_iterator{begin()};
   }
   LIBC_INLINE constexpr const_reverse_iterator rend() const {
-    return const_reverse_iterator{Data};
+    return const_reverse_iterator{begin()};
   }
   LIBC_INLINE constexpr const_reverse_iterator crend() const { return rend(); }
 };

libc/src/__support/CPP/iterator.h

@@ -92,74 +92,6 @@ template <typename Iter> class reverse_iterator {
   }
 };
 
-template <typename Iter> class iterator {
-  Iter current;
-
-public:
-  using reference = typename iterator_traits<Iter>::reference;
-  using value_type = typename iterator_traits<Iter>::value_type;
-  using iterator_type = Iter;
-
-  LIBC_INLINE iterator() : current() {}
-  LIBC_INLINE constexpr explicit iterator(Iter it) : current(it) {}
-
-  template <typename Other,
-            cpp::enable_if_t<!cpp::is_same_v<Iter, Other> &&
-                                 cpp::is_convertible_v<const Other &, Iter>,
-                             int> = 0>
-  LIBC_INLINE constexpr explicit iterator(const Other &it) : current(it) {}
-
-  LIBC_INLINE friend constexpr bool operator==(const iterator &lhs,
-                                               const iterator &rhs) {
-    return lhs.base() == rhs.base();
-  }
-
-  LIBC_INLINE friend constexpr bool operator!=(const iterator &lhs,
-                                               const iterator &rhs) {
-    return lhs.base() != rhs.base();
-  }
-
-  LIBC_INLINE friend constexpr bool operator<(const iterator &lhs,
-                                              const iterator &rhs) {
-    return lhs.base() < rhs.base();
-  }
-
-  LIBC_INLINE friend constexpr bool operator<=(const iterator &lhs,
-                                               const iterator &rhs) {
-    return lhs.base() <= rhs.base();
-  }
-
-  LIBC_INLINE friend constexpr bool operator>(const iterator &lhs,
-                                              const iterator &rhs) {
-    return lhs.base() > rhs.base();
-  }
-
-  LIBC_INLINE friend constexpr bool operator>=(const iterator &lhs,
-                                               const iterator &rhs) {
-    return lhs.base() >= rhs.base();
-  }
-
-  LIBC_INLINE constexpr iterator_type base() const { return current; }
-
-  LIBC_INLINE constexpr reference operator*() const {
-    Iter tmp = current;
-    return *tmp;
-  }
-  LIBC_INLINE constexpr iterator operator--() {
-    --current;
-    return *this;
-  }
-  LIBC_INLINE constexpr iterator &operator++() {
-    ++current;
-    return *this;
-  }
-  LIBC_INLINE constexpr iterator operator++(int) {
-    iterator tmp(*this);
-    ++current;
-    return tmp;
-  }
-};
-
 } // namespace cpp
 } // namespace LIBC_NAMESPACE
 

libc/src/__support/fixedvector.h

@@ -58,10 +58,6 @@ template <typename T, size_t CAPACITY> class FixedVector {
   // can easily swap one data structure for the other.
   static void destroy(FixedVector<T, CAPACITY> *store) { store->reset(); }
 
-  using iterator = typename cpp::array<T, CAPACITY>::iterator;
-  LIBC_INLINE constexpr iterator begin() { return iterator{&store[0]}; }
-  LIBC_INLINE constexpr iterator end() { return iterator{&store[item_count]}; }
-
   using reverse_iterator = typename cpp::array<T, CAPACITY>::reverse_iterator;
   LIBC_INLINE constexpr reverse_iterator rbegin() {
     return reverse_iterator{&store[item_count]};