This patch fixes T60171 by adding a dummy read from the `dummy` vertex attribute to `hair_get_pos_tan_binor_time` in `common_hair_lib.glsl`. Confirmed to work on my machine (macOS 10.14.4 Beta, Radeon R9 M295X). According to my experiments regarding this issue, the problem is triggered when all of the following conditions are met: (a) the shader has no vertex reads; (b) the index buffer is ≥ 256KiB. I can't really give an explanation of this misbehavior because of the video driver's closed-source nature. Reviewers: fclem Reviewed By: fclem Subscribers: zeddb Maniphest Tasks: T60171 Differential Revision: https://developer.blender.org/D4490