The IO scalarization pass that we run to help with linking end up
turning some shader I/O such as that for tessellation and geometry
shaders into many scalar URB operations rather than one vector one. To
alleviate this, we now vectorize the I/O once again. This fixes a 10%
performance regression in the GfxBench tessellation test that was caused
by scalarizing.
Shader-db results on Kaby Lake:
total instructions in shared programs: 15224023 -> 15220871 (-0.02%)
instructions in affected programs: 342009 -> 338857 (-0.92%)
helped: 1236
HURT: 443
total spills in shared programs: 23471 -> 23465 (-0.03%)
spills in affected programs: 6 -> 0
helped: 1
HURT: 0
total fills in shared programs: 31770 -> 31766 (-0.01%)
fills in affected programs: 4 -> 0
helped: 1
HURT: 0
Cycles was just a lot of churn do to moves being different places. Most
of the pure churn in instructions was +/- one or two instructions in
fragment shaders.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107510
Fixes: 4434591bf5 "intel/nir: Call nir_lower_io_to_scalar_early"
Fixes: 8d8222461f "intel/nir: Enable nir_opt_find_array_copies"
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Jason Ekstrand
6d5d89d25a