With the following test :
dEQP-VK.spirv_assembly.instruction.terminate_invocation.terminate.no_out_of_bounds_load
There is a :
shader_start:
... <- no control flow
g0 = some_alu
g1 = fbl
g2 = broadcast g3, g1
g4 = get_buffer_size g2
... <- no control flow
halt <- on some lanes
g5 = send <surface>, g4
eliminate_find_live_channel will remove the fbl/broadcast because it
assumes lane0 is active at get_buffer_size :
shader_start:
... <- no control flow
g0 = some_alu
g4 = get_buffer_size g0
... <- no control flow
halt <- on some lanes
g5 = send <surface>, g4
But then the instruction scheduler will move the get_buffer_size after
the halt :
shader_start:
... <- no control flow
halt <- on some lanes
g0 = some_alu
g4 = get_buffer_size g0
g5 = send <surface>, g4
get_buffer_size pulls the surface index from lane0 in g0 which could
have been turned off by the halt and we end up accessing an invalid
surface handle.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: mesa-stable
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20765>
Lionel Landwerlin
9471ffa70a