[llvm] r373039 - Revert r373034

[Nicholas Allegra via llvm-commits]

Author: comex
Date: Thu Sep 26 18:58:31 2019
New Revision: 373039

URL: http://llvm.org/viewvc/llvm-project?rev=373039&view=rev
Log:
Revert r373034

It breaks the build on MSVC.


Modified:
    llvm/trunk/include/llvm/ADT/STLExtras.h
    llvm/trunk/include/llvm/ADT/iterator_range.h

Modified: llvm/trunk/include/llvm/ADT/STLExtras.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/STLExtras.h?rev=373039&r1=373038&r2=373039&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/STLExtras.h (original)
+++ llvm/trunk/include/llvm/ADT/STLExtras.h Thu Sep 26 18:58:31 2019
@@ -1573,14 +1573,6 @@ template <class Ptr> auto to_address(con
 }
 template <class T> constexpr T *to_address(T *P) { return P; }
 
-template <typename R>
-auto index(R &&TheRange,
-  typename std::iterator_traits<detail::IterOfRange<R>>::difference_type N)
-  -> decltype(TheRange.begin()[N]) {
-  assert(N < TheRange.end() - TheRange.begin() && "Index out of range!");
-  return TheRange.begin()[N];
-}
-
 } // end namespace llvm
 
 #endif // LLVM_ADT_STLEXTRAS_H

Modified: llvm/trunk/include/llvm/ADT/iterator_range.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/iterator_range.h?rev=373039&r1=373038&r2=373039&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/iterator_range.h (original)
+++ llvm/trunk/include/llvm/ADT/iterator_range.h Thu Sep 26 18:58:31 2019
@@ -20,17 +20,9 @@
 
 #include <iterator>
 #include <utility>
-#include <cassert>
 
 namespace llvm {
 
-template <typename T>
-constexpr bool is_random_iterator() {
-  return std::is_same<
-    typename std::iterator_traits<T>::iterator_category,
-    std::random_access_iterator_tag>::value;
-}
-
 /// A range adaptor for a pair of iterators.
 ///
 /// This just wraps two iterators into a range-compatible interface. Nothing
@@ -66,31 +58,11 @@ template <typename T> iterator_range<T>
   return iterator_range<T>(std::move(p.first), std::move(p.second));
 }
 
-/// Non-random-iterator version
 template <typename T>
-auto drop_begin(T &&t, int n) ->
-  typename std::enable_if<!is_random_iterator<decltype(adl_begin(t))>(),
-  iterator_range<decltype(adl_begin(t))>>::type {
-  auto begin = adl_begin(t);
-  auto end = adl_end(t);
-  for (int i = 0; i < n; i++) {
-    assert(begin != end);
-    ++begin;
-  }
-  return make_range(begin, end);
+iterator_range<decltype(adl_begin(std::declval<T>()))> drop_begin(T &&t,
+                                                                  int n) {
+  return make_range(std::next(adl_begin(t), n), adl_end(t));
 }
-
-/// Optimized version for random iterators
-template <typename T>
-auto drop_begin(T &&t, int n) ->
-  typename std::enable_if<is_random_iterator<decltype(adl_begin(t))>(),
-  iterator_range<decltype(adl_begin(t))>>::type {
-  auto begin = adl_begin(t);
-  auto end = adl_end(t);
-  assert(end - begin >= n && "Dropping more elements than exist!");
-  return make_range(std::next(begin, n), end);
-}
-
 }
 
 #endif