[llvm] [ubsan] Add [undefined] section to ignorelist (PR #202380)

[Vitaly Buka via llvm-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/202380

`-fsanitize-blacklist` this files passed as which apply to any sanitizers.
So if Ubsan is combined with Asan, as-is these suppressions apply to Asan
which is clearly was not the intention.


>From c8619440e507652d5912ba641ea6e4ce614e222e Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Mon, 8 Jun 2026 09:09:50 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.7
---
 llvm/utils/sanitizers/ubsan_ignorelist.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/llvm/utils/sanitizers/ubsan_ignorelist.txt b/llvm/utils/sanitizers/ubsan_ignorelist.txt
index 144ab1f4685d1..e4bfa62f64c77 100644
--- a/llvm/utils/sanitizers/ubsan_ignorelist.txt
+++ b/llvm/utils/sanitizers/ubsan_ignorelist.txt
@@ -3,6 +3,8 @@
 # because libstdc++ has some undefined behavior issues
 # in some of the headers, in particular, stl_tree.h.
 
+[undefined]
+
 # upcast of address with insufficient space for an object of type std::_Rb_tree_node<...>
 src:*bits/stl_tree.h