[Clang] Overflow Pattern Exclusion - rename some patterns, enhance docs (#105709)

From @vitalybuka's review on
https://github.com/llvm/llvm-project/pull/104889:
- [x] remove unused variable in tests
- [x] rename `post-decr-while` --> `unsigned-post-decr-while`
- [x] split `add-overflow-test` into `add-unsigned-overflow-test` and
`add-signed-overflow-test`
- [x] be more clear about defaults within docs
- [x] add table to docs

Here's a screenshot of the rendered table so you don't have to build the
html docs yourself to inspect the layout:

![image](https://github.com/user-attachments/assets/5d3497c4-5f5a-4579-b29b-96a0fd192faa)


CCs: @vitalybuka

---------

Signed-off-by: Justin Stitt <justinstitt@google.com>
Co-authored-by: Vitaly Buka <vitalybuka@google.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 2a726bba2dd3..af11bc20a3b6 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -2785,7 +2785,7 @@ static bool matchesPostDecrInWhile(const UnaryOperator *UO, bool isInc,
   if (isInc || isPre)
     return false;
 
-  // -fsanitize-undefined-ignore-overflow-pattern=post-decr-while
+  // -fsanitize-undefined-ignore-overflow-pattern=unsigned-post-decr-while
   if (!Ctx.getLangOpts().isOverflowPatternExcluded(
           LangOptions::OverflowPatternExclusionKind::PostDecrInWhile))
     return false;