[gcc r16-5470] ada: Improve Append performance for Ada.Containers.Bounded_Vectors

[Marc Poulhies]

https://gcc.gnu.org/g:f4312f92c0b723c607419844818b075b8c020b9c

commit r16-5470-gf4312f92c0b723c607419844818b075b8c020b9c
Author: Steve Baird <baird@adacore.com>
Date:   Mon Nov 10 14:36:33 2025 -0800

    ada: Improve Append performance for Ada.Containers.Bounded_Vectors
    
    In (any instance of) Ada.Containers.Bounded_Vectors, for the procedure
    overload of Append that takes parameters of types Vector and Element_Type,
    improve performance in the case where either of the GNAT-defined checks
    Container_Checks or Tampering_Check are suppressed.
    
    gcc/ada/ChangeLog:
    
            * libgnat/a-cobove.adb
            (Append): Add an equivalent fast path for the case where tampering
            checks are suppressed.

Diff:
---
 gcc/ada/libgnat/a-cobove.adb | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/libgnat/a-cobove.adb b/gcc/ada/libgnat/a-cobove.adb
index 3b5b4a61bf5b..6371fb57d28a 100644
--- a/gcc/ada/libgnat/a-cobove.adb
+++ b/gcc/ada/libgnat/a-cobove.adb
@@ -363,7 +363,15 @@ package body Ada.Containers.Bounded_Vectors is
                      New_Item  :        Element_Type)
    is
    begin
-      Insert (Container, Last_Index (Container) + 1, New_Item, 1);
+      if T_Check then
+         --  handle the general case
+         Insert (Container, Last_Index (Container) + 1, New_Item, 1);
+      else
+         --  The fast path.
+         --  The first (but not the second) statement may fail a check.
+         Container.Elements (To_Array_Index (Container.Last) + 1) := New_Item;
+         Container.Last := Container.Last + 1;
+      end if;
    end Append;
 
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