[clang] [Clang] Re-land Overflow Pattern Exclusions (PR #104889)

[Justin Stitt via cfe-commits]

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@@ -438,6 +438,36 @@ Moved checkers
 Sanitizers
 ----------
 
+- Added the ``-fsanitize-undefined-ignore-overflow-pattern`` flag which can be
+  used to disable specific overflow-dependent code patterns. The supported
+  patterns are: ``add-overflow-test``, ``negated-unsigned-const``, and
+  ``post-decr-while``. The sanitizer instrumentation can be toggled off for all
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JustinStitt wrote:

It is not explicitly stated but no patterns are excluded by default. This is somewhat evident by "... _can be_ used to disable" and "sanitizer instrumentation _can be_ toggled off".



https://github.com/llvm/llvm-project/pull/104889