[gcc r13-4304] libstdc++: Add always_inline to trivial iterator operations

[Jonathan Wakely]

https://gcc.gnu.org/g:6bd8d119227ff9a4740739e91898258bcd854b9b

commit r13-4304-g6bd8d119227ff9a4740739e91898258bcd854b9b
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Nov 24 21:13:36 2022 +0000

    libstdc++: Add always_inline to trivial iterator operations
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/stl_iterator_base_funcs.h (__distance):
            Add always_inline attribute to overload for random
            access iterators.
            (advance, distance, next, prev): Add always_inline attribute to
            inline functions that just forward to another function.

Diff:
---
 libstdc++-v3/include/bits/stl_iterator_base_funcs.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/include/bits/stl_iterator_base_funcs.h b/libstdc++-v3/include/bits/stl_iterator_base_funcs.h
index 1551b226ff4..25dddb3e7e8 100644
--- a/libstdc++-v3/include/bits/stl_iterator_base_funcs.h
+++ b/libstdc++-v3/include/bits/stl_iterator_base_funcs.h
@@ -94,6 +94,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
     }
 
   template<typename _RandomAccessIterator>
+    __attribute__((__always_inline__))
     inline _GLIBCXX14_CONSTEXPR
     typename iterator_traits<_RandomAccessIterator>::difference_type
     __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
@@ -141,7 +142,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
    *  and are constant time.  For other %iterator classes they are linear time.
   */
   template<typename _InputIterator>
-    _GLIBCXX_NODISCARD
+    _GLIBCXX_NODISCARD __attribute__((__always_inline__))
     inline _GLIBCXX17_CONSTEXPR
     typename iterator_traits<_InputIterator>::difference_type
     distance(_InputIterator __first, _InputIterator __last)
@@ -214,6 +215,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
    *  and are constant time.  For other %iterator classes they are linear time.
   */
   template<typename _InputIterator, typename _Distance>
+    __attribute__((__always_inline__))
     inline _GLIBCXX17_CONSTEXPR void
     advance(_InputIterator& __i, _Distance __n)
     {
@@ -225,7 +227,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
 #if __cplusplus >= 201103L
 
   template<typename _InputIterator>
-    _GLIBCXX_NODISCARD
+    _GLIBCXX_NODISCARD [[__gnu__::__always_inline__]]
     inline _GLIBCXX17_CONSTEXPR _InputIterator
     next(_InputIterator __x, typename
 	 iterator_traits<_InputIterator>::difference_type __n = 1)
@@ -237,7 +239,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
     }
 
   template<typename _BidirectionalIterator>
-    _GLIBCXX_NODISCARD
+    _GLIBCXX_NODISCARD [[__gnu__::__always_inline__]]
     inline _GLIBCXX17_CONSTEXPR _BidirectionalIterator
     prev(_BidirectionalIterator __x, typename
 	 iterator_traits<_BidirectionalIterator>::difference_type __n = 1)