[libcxx-commits] [libcxx] 8dfca82 - [libc++][NFC] Don't use std::distance in std::equal (#177113)

[via libcxx-commits]

Author: Nikolas Klauser
Date: 2026-01-27T10:29:12+01:00
New Revision: 8dfca82a7cb3ee4d9f768a6c3a61236ffb329a22

URL: https://github.com/llvm/llvm-project/commit/8dfca82a7cb3ee4d9f768a6c3a61236ffb329a22
DIFF: https://github.com/llvm/llvm-project/commit/8dfca82a7cb3ee4d9f768a6c3a61236ffb329a22.diff

LOG: [libc++][NFC] Don't use std::distance in std::equal (#177113)

We don't need to use `std::distance`, since we know for a fact that we
have random access iterators in that place. Instead, we can just
subtract the iterators, avoiding a bunch of template machinery and
imrpoving compile times a bit.

Added: 
    

Modified: 
    libcxx/include/__algorithm/equal.h

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__algorithm/equal.h b/libcxx/include/__algorithm/equal.h
index 753cac5a469e4..ca536dc61e235 100644
--- a/libcxx/include/__algorithm/equal.h
+++ b/libcxx/include/__algorithm/equal.h
@@ -16,15 +16,12 @@
 #include <__config>
 #include <__functional/identity.h>
 #include <__fwd/bit_reference.h>
-#include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
-#include <__memory/pointer_traits.h>
 #include <__string/constexpr_c_functions.h>
 #include <__type_traits/desugars_to.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/invoke.h>
 #include <__type_traits/is_equality_comparable.h>
-#include <__type_traits/is_same.h>
 #include <__type_traits/is_volatile.h>
 #include <__utility/move.h>
 
@@ -251,7 +248,7 @@ equal(_InputIterator1 __first1,
       __has_random_access_iterator_category<_InputIterator1>::value &&
       __has_random_access_iterator_category<_InputIterator2>::value;
   if constexpr (__both_random_access) {
-    if (std::distance(__first1, __last1) != std::distance(__first2, __last2))
+    if (__last1 - __first1 != __last2 - __first2)
       return false;
   }
   __identity __proj;