Mark invariant.group as experimental

[davide]

docs/LangRef.rst

12618

s/it's/its/

include/llvm/IR/Intrinsics.td

640

Can you use "its semantics" everywhere

[Prazek]

• fixes

[davide]

LGTM (assuming you grepped and replaced all the uses in the documentation).

[Prazek]

Thanks Davide!

[davide]

Was this ever committed?

docs/LangRef.rst

.. code-block:: llvm
    ...
    !0 = !{!1, !2} ; a list of loop identifiers
    !1 = !{!1} ; an identifier for the inner loop
    !2 = !{!2} ; an identifier for the outer loop
 
 '``invariant.group``' Metadata
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-The ``invariant.group`` metadata may be attached to ``load``/``store`` instructions.
+The experimental ``invariant.group`` metadata may be attached to
+``load``/``store`` instructions.
 The existence of the ``invariant.group`` metadata on the instruction tells 
 the optimizer that every ``load`` and ``store`` to the same pointer operand 
 within the same invariant group can be assumed to load or store the same  
 value (but see the ``llvm.invariant.group.barrier`` intrinsic which affects 
 when two pointers are considered the same). Pointers returned by bitcast or
 getelementptr with only zero indices are considered the same.
 
 Examples:

 to the SSA value of the pointer operand.
 
 .. code-block:: llvm
   
   %v = load i8, i8* %x, !invariant.group !0
   ; if %x mustalias %y then we can replace the above instruction with
   %v = load i8, i8* %y
 
+Note that this is an experimental feature, which means that semantics might
+change in the future.
 
 '``type``' Metadata
 ^^^^^^^^^^^^^^^^^^^
 
 See :doc:`TypeMetadata`.
 
 '``associated``' Metadata
 ^^^^^^^^^^^^^^^^^^^^^^^^^
::
 
       declare i8* @llvm.invariant.group.barrier(i8* <ptr>)
 
 Overview:
 """""""""
 
 The '``llvm.invariant.group.barrier``' intrinsic can be used when an invariant 
 established by invariant.group metadata no longer holds, to obtain a new pointer
-value that does not carry the invariant information.
+value that does not carry the invariant information. It is an experimental
+intrinsic, which means that it's semantics might change in the future.
 
 
 Arguments:
 """"""""""
 
 The ``llvm.invariant.group.barrier`` takes only one argument, which is
 the pointer to the memory for which the ``invariant.group`` no longer holds.
 

include/llvm/IR/Intrinsics.td

 
 // invariant.group.barrier can't be marked with 'readnone' (IntrNoMem),
 // because it would cause CSE of two barriers with the same argument.
 // Readonly and argmemonly says that barrier only reads its argument and
 // it can be CSE only if memory didn't change between 2 barriers call,
 // which is valid.
 // The argument also can't be marked with 'returned' attribute, because
 // it would remove barrier.
+// Note that it is still experimental, which means that semantics of it
+// might change in the future.
 def int_invariant_group_barrier : Intrinsic<[llvm_ptr_ty],
                                             [llvm_ptr_ty],
                                             [IntrInaccessibleMemOnly]>;
 
 //===------------------------ Stackmap Intrinsics -------------------------===//
 //
 def int_experimental_stackmap : Intrinsic<[],
                                   [llvm_i64_ty, llvm_i32_ty, llvm_vararg_ty],