It turns out the original condition for detecting sysval semantics was wrong (in a way that it would allow more rather than deny what it shouldn't, but still).
I made a local test which tests all possible SV_ semantic names on top of the updated MR (attached). I also extended VS test in the MR a bit.
[0001-d3d11-tests-Add-more-tests-for-CreateInputLayout.patch](/uploads/f4cd48f56cc900279f052550810d6545/0001-d3d11-tests-Add-more-tests-for-CreateInputLayout.patch)
v2: - change is_mandatory_shader_input -> is_vs_sysval_semantic, changed the condition inside it as well; - add find_input_element() helper; - typo in check_layout_element_exclusion(); - check for sysval semantics in check_layout_element_exclusion() explicitly; there is still a special case for compute shader/ - layout_desc->Format -> layout_desc[0].Format.