diff options
Diffstat (limited to 'llvm/docs/LangRef.rst')
| -rw-r--r-- | llvm/docs/LangRef.rst | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst index 22295287c35..f20f4385c2f 100644 --- a/llvm/docs/LangRef.rst +++ b/llvm/docs/LangRef.rst @@ -7450,9 +7450,9 @@ Syntax: :: - <result> = getelementptr <ty>, <ty>* <ptrval>{, <ty> <idx>}* - <result> = getelementptr inbounds <ty>, <ty>* <ptrval>{, <ty> <idx>}* - <result> = getelementptr <ty>, <ptr vector> <ptrval>, <vector index type> <idx> + <result> = getelementptr <ty>, <ty>* <ptrval>{, [inrange] <ty> <idx>}* + <result> = getelementptr inbounds <ty>, <ty>* <ptrval>{, [inrange] <ty> <idx>}* + <result> = getelementptr <ty>, <ptr vector> <ptrval>, [inrange] <vector index type> <idx> Overview: """"""""" @@ -7569,6 +7569,18 @@ though, even if it happens to point into allocated storage. See the :ref:`Pointer Aliasing Rules <pointeraliasing>` section for more information. +If the ``inrange`` keyword is present before any index, loading from or +storing to any pointer derived from the ``getelementptr`` has undefined +behavior if the load or store would access memory outside of the bounds of +the element selected by the index marked as ``inrange``. The result of a +pointer comparison or ``ptrtoint`` (including ``ptrtoint``-like operations +involving memory) involving a pointer derived from a ``getelementptr`` with +the ``inrange`` keyword is undefined, with the exception of comparisons +in the case where both operands are in the range of the element selected +by the ``inrange`` keyword, inclusive of the address one past the end of +that element. Note that the ``inrange`` keyword is currently only allowed +in constant ``getelementptr`` expressions. + The getelementptr instruction is often confusing. For some more insight into how it works, see :doc:`the getelementptr FAQ <GetElementPtr>`. |
