[clang] [Clang] Add -fwrapv-pointer flag (PR #122486)

[Aaron Ballman via cfe-commits]

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@@ -79,7 +79,15 @@ code bases.
   Undefined behavior due to pointer addition overflow can be reliably detected
   using ``-fsanitize=pointer-overflow``. It is also possible to use
   ``-fno-strict-overflow`` to opt-in to a language dialect where signed integer
-  and pointer overflow are well-defined.
+  and pointer overflow are well-defined. Since Clang 20, it is also possible
+  to use ``-fwrapv-pointer`` to only make pointer overflow well-defined, while
+  not affecting the behavior of signed integer overflow.
+
+- The ``-fwrapv`` flag now only makes signed integer overflow well-defined,
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AaronBallman wrote:

Curiously enough, we only ever documented the signed integer overflow behavior, not the pointer overflow: https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-fwrapv

https://github.com/llvm/llvm-project/pull/122486