[llvm] 2be3fca - [STLExtras] Remove incorrect hack to make indexed_accessor_range operator== compatible with C++20 (#72220)

[via llvm-commits]

Author: Utkarsh Saxena
Date: 2023-11-14T14:37:51+01:00
New Revision: 2be3fcab0e792d934698d5f6af7b7e17d8848ca4

URL: https://github.com/llvm/llvm-project/commit/2be3fcab0e792d934698d5f6af7b7e17d8848ca4
DIFF: https://github.com/llvm/llvm-project/commit/2be3fcab0e792d934698d5f6af7b7e17d8848ca4.diff

LOG: [STLExtras] Remove incorrect hack to make indexed_accessor_range operator== compatible with C++20 (#72220)

This partially reverts c312f025940d79b858166b80c50526558864d54e

The motivation behind this is unclear and the change predates the clang
[implementation](https://github.com/llvm/llvm-project/commit/38b9d313e6945804fffc654f849cfa05ba2c713d)
of
[p2468r2](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p2468r2.html)
so I am not sure if it was ever intended to work. Rewritten template
operators were broken since the beginning.

Moreover, moving away from `friend` would be beneficial as these would
only accepted once clang revises its implementation for fixing
https://github.com/llvm/llvm-project/issues/70210. It also helps in
making sure that older compilers still compile LLVM (in C++20).

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index 18bc4d108b156bf..e42b0e8d1b27b71 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -1291,15 +1291,11 @@ class indexed_accessor_range_base {
   }
 
   /// Compare this range with another.
-  template <typename OtherT>
-  friend bool operator==(const indexed_accessor_range_base &lhs,
-                         const OtherT &rhs) {
-    return std::equal(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
-  }
-  template <typename OtherT>
-  friend bool operator!=(const indexed_accessor_range_base &lhs,
-                         const OtherT &rhs) {
-    return !(lhs == rhs);
+  template <typename OtherT> bool operator==(const OtherT &rhs) const {
+    return std::equal(begin(), end(), rhs.begin(), rhs.end());
+  }
+  template <typename OtherT> bool operator!=(const OtherT &rhs) const {
+    return !(*this == rhs);
   }
 
   /// Return the size of this range.