[gcc r17-4787] libstdc++: Fix failing performance test

[Jonathan Wakely]

https://gcc.gnu.org/g:4e596c9800ec9441409275f79326805a4fde8358

commit r17-4787-g4e596c9800ec9441409275f79326805a4fde8358
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Sep 29 15:17:25 2026 +0100

    libstdc++: Fix failing performance test
    
    This test no longer builds because (file >> line) is ill-formed in
    C++20, since r11-2581-g17abcc77341584 which implemented LWG 2499.
    
    There's no reason to use a dynamically-allocated array when the length
    is a small constant. We can just use an array on the stack.
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/performance/27_io/ifstream_extract_chars.cc: Use
            stack array instead of dynamic allocation.
    
    Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>

Diff:
---
 libstdc++-v3/testsuite/performance/27_io/ifstream_extract_chars.cc | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libstdc++-v3/testsuite/performance/27_io/ifstream_extract_chars.cc b/libstdc++-v3/testsuite/performance/27_io/ifstream_extract_chars.cc
index e3c754063279..89c84215108e 100644
--- a/libstdc++-v3/testsuite/performance/27_io/ifstream_extract_chars.cc
+++ b/libstdc++-v3/testsuite/performance/27_io/ifstream_extract_chars.cc
@@ -34,7 +34,7 @@ int main()
   const unsigned lines = 200000;
   const unsigned line_length = 200;
 
-  char* line = new char[line_length + 2];
+  char line[line_length + 2];
 
   // Construct data.
   {
@@ -76,7 +76,6 @@ int main()
     clear_counters(time, resource);
   }
 
-  delete[] line;
   unlink(filename);
   return 0;
 }