[gcc r13-5285] tree-optimization/108449 - keep maybe_special_function_p behavior

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:106f99406312d7ed47434de53c180718225ffa5e

commit r13-5285-g106f99406312d7ed47434de53c180718225ffa5e
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Jan 19 08:44:25 2023 +0100

    tree-optimization/108449 - keep maybe_special_function_p behavior
    
    When we have a static declaration without definition we diagnose
    that and turn it into an extern declaration.  That can alter
    the outcome of maybe_special_function_p here and there's really
    no point in doing that, so don't.
    
            PR tree-optimization/108449
            * cgraphunit.cc (check_global_declaration): Do not turn
            undefined statics into externs.
    
            * gcc.dg/pr108449.c: New testcase.

Diff:
---
 gcc/cgraphunit.cc               | 2 --
 gcc/testsuite/gcc.dg/pr108449.c | 5 +++++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/gcc/cgraphunit.cc b/gcc/cgraphunit.cc
index 59ce2708b7b..832818d651f 100644
--- a/gcc/cgraphunit.cc
+++ b/gcc/cgraphunit.cc
@@ -1087,8 +1087,6 @@ check_global_declaration (symtab_node *snode)
       else
 	warning (OPT_Wunused_function, "%q+F declared %<static%> but never "
 				       "defined", decl);
-      /* This symbol is effectively an "extern" declaration now.  */
-      TREE_PUBLIC (decl) = 1;
     }
 
   /* Warn about static fns or vars defined but not used.  */
diff --git a/gcc/testsuite/gcc.dg/pr108449.c b/gcc/testsuite/gcc.dg/pr108449.c
new file mode 100644
index 00000000000..4a3ae5b3ed4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr108449.c
@@ -0,0 +1,5 @@
+/* { dg-do compile } */
+/* { dg-options "-O" } */
+
+static int vfork(); /* { dg-warning "used but never defined" } */
+void f() { vfork(); }