From 74f956c416d5b0b37b4c2d6b957167bb203502c3 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Thu, 21 Jan 2016 16:37:20 -0800 Subject: [PATCH] i965: Use nir_lower_load_const_to_scalar(). I don't know why, but we never hooked up this pass Eric wrote. Otherwise, you can end up with stupid scalarized code such as: vec4 ssa_7 = load_const (0.0, 0.0, 0.0, 0.0) vec4 ssa_8 = ... vec1 ssa_9 = feq ssa_8, ssa_7 vec1 ssa_10 = feq ssa_8.y, ssa_7.y vec1 ssa_11 = feq ssa_8, ssa_7.z vec1 ssa_12 = feq ssa_8.y, ssa_7.w ssa_8.xyxy == <0, 0, 0, 0> should only take two feq instructions. shader-db on Skylake: total instructions in shared programs: 9121153 -> 9120749 (-0.00%) instructions in affected programs: 32421 -> 32017 (-1.25%) helped: 277 HURT: 69 total cycles in shared programs: 69003364 -> 69000912 (-0.00%) cycles in affected programs: 899186 -> 896734 (-0.27%) helped: 313 HURT: 403 This also prevents regressions when disabling channel expressions. v2: Don't call opt_cse afterwards (requested by Matt). It should happen in the optimization loop below anyway. Signed-off-by: Kenneth Graunke Reviewed-by: Eduardo Lima Mitev Reviewed-by: Matt Turner --- src/mesa/drivers/dri/i965/brw_nir.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c index 287f935..46b5116 100644 --- a/src/mesa/drivers/dri/i965/brw_nir.c +++ b/src/mesa/drivers/dri/i965/brw_nir.c @@ -482,6 +482,10 @@ brw_preprocess_nir(nir_shader *nir, bool is_scalar) nir = nir_optimize(nir, is_scalar); + if (is_scalar) { + OPT_V(nir_lower_load_const_to_scalar); + } + /* Lower a bunch of stuff */ OPT_V(nir_lower_var_copies); -- 2.7.4