[gcc r13-4744] contrib: make warnings unique in filter-clang-warnings.py

[Martin Liska <marxin@gcc.gnu.org>]

https://gcc.gnu.org/g:d386d399205e68e02b357dfcd96b9a4b91e4f295

commit r13-4744-gd386d399205e68e02b357dfcd96b9a4b91e4f295
Author: Martin Liska <mliska@suse.cz>
Date:   Fri Dec 16 13:07:27 2022 +0100

    contrib: make warnings unique in filter-clang-warnings.py
    
    contrib/ChangeLog:
    
            * filter-clang-warnings.py: Print each warning only one time.

Diff:
---
 contrib/filter-clang-warnings.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/contrib/filter-clang-warnings.py b/contrib/filter-clang-warnings.py
index c426bce5eb5..0973d74d8d9 100755
--- a/contrib/filter-clang-warnings.py
+++ b/contrib/filter-clang-warnings.py
@@ -72,7 +72,7 @@ args = parser.parse_args()
 
 lines = [line.strip() for line in open(args.log)]
 total = 0
-messages = []
+messages = set()
 for line in lines:
     token = ': warning: '
     i = line.find(token)
@@ -81,7 +81,7 @@ for line in lines:
         message = line[i + len(token):]
         if not skip_warning(location, message):
             total += 1
-            messages.append(line)
+            messages.add(line)
 
 for line in sorted(messages):
     print(line)