[clang] [llvm] [Clang] Add __builtin_assume_dereferenceable to encode deref assumption. (PR #121789)

[Erich Keane via llvm-commits]

================
@@ -2761,6 +2761,41 @@ etc.).
 
 Query for this feature with ``__has_builtin(__builtin_assume_separate_storage)``.
 
+``__builtin_assume_dereferenceable``
+-------------------------------------
+
+``__builtin_assume_derefernceable`` is used to provide the optimizer with the
+knowledge that the pointer argument P is dereferenceable up to the specified
+number of bytes.
+
+**Syntax**:
+
+.. code-block:: c++
+
+    __builtin_assume_dereferenceable(const void *, size_t)
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erichkeane wrote:

Is it just Github?  There is a lot of weirdly italic stuff in this section of the patch.

https://github.com/llvm/llvm-project/pull/121789