[gcc r16-9842] fortran: Fix invalid read with 'use, only:' [PR128067]

[Harald Anlauf via Gcc-cvs]

https://gcc.gnu.org/g:a79e6dce98dd9550636f3034af2a55cd5cad0e15

commit r16-9842-ga79e6dce98dd9550636f3034af2a55cd5cad0e15
Author: Harald Anlauf <anl...@gmx.de>
Date:   Fri Oct 23 21:27:01 2026 +0200

    fortran: Fix invalid read with 'use, only:' [PR128067]
    
            PR fortran/128067
    
    gcc/fortran/ChangeLog:
    
            * module.cc (load_needed): Prevent scanning of empty name for
            prefix "__".
    
    (cherry picked from commit 488509e6d4b243e5bda750b2d4b2fd8a80a1572f)

Diff:
---
 gcc/fortran/module.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gcc/fortran/module.cc b/gcc/fortran/module.cc
index ef8b13291d2d..649928f20a50 100644
--- a/gcc/fortran/module.cc
+++ b/gcc/fortran/module.cc
@@ -5556,7 +5556,9 @@ load_needed (pointer_info *p)
      but not used warnings; don't mark internal symbols such as __vtab,
      __def_init etc. Only mark them if they have been explicitly loaded.  */
 
-  if (only_flag && sym->name[0] != '_' && sym->name[1] != '_')
+  if (only_flag
+      && sym->name[0] != '\0'
+      && !(sym->name[0] == '_' && sym->name[1] == '_'))
     {
       gfc_use_rename *u;