[gcc r16-1700] fortran: Avoid freeing uninitialized value

[Martin Jambor]

https://gcc.gnu.org/g:bf6078d2aaee8b240b7425b9788d8038cd45c8f3

commit r16-1700-gbf6078d2aaee8b240b7425b9788d8038cd45c8f3
Author: Martin Jambor <mjambor@suse.cz>
Date:   Thu Jun 26 11:25:20 2025 +0200

    fortran: Avoid freeing uninitialized value
    
    When compiling fortran/match.cc, clang emits a warning
    
      fortran/match.cc:5301:7: warning: variable 'p' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
    
    which looks accurate, so this patch adds an initialization of p to
    avoid the use.
    
    gcc/fortran/ChangeLog:
    
    2025-06-23  Martin Jambor  <mjambor@suse.cz>
    
            * match.cc (gfc_match_nullify): Initialize p to NULL;

Diff:
---
 gcc/fortran/match.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/fortran/match.cc b/gcc/fortran/match.cc
index aa0b04afd563..8355a390ee08 100644
--- a/gcc/fortran/match.cc
+++ b/gcc/fortran/match.cc
@@ -5293,7 +5293,7 @@ match
 gfc_match_nullify (void)
 {
   gfc_code *tail;
-  gfc_expr *e, *p;
+  gfc_expr *e, *p = NULL;
   match m;
 
   tail = NULL;