intel/compiler: Use compare rematerialization pass

Almost all of the spill / fill benefit is in Deus Ex.

Haswell and all Gen8+ platforms had similar results. (Ice Lake shown)
total instructions in shared programs: 17224438 -> 17196395 (-0.16%)
instructions in affected programs: 1518658 -> 1490615 (-1.85%)
helped: 1550
HURT: 3
helped stats (abs) min: 1 max: 170 x̄: 18.11 x̃: 2
helped stats (rel) min: 0.04% max: 8.35% x̄: 1.12% x̃: 0.45%
HURT stats (abs)   min: 5 max: 10 x̄: 6.67 x̃: 5
HURT stats (rel)   min: 0.32% max: 0.41% x̄: 0.35% x̃: 0.32%
95% mean confidence interval for instructions value: -19.86 -16.26
95% mean confidence interval for instructions %-change: -1.19% -1.04%
Instructions are helped.

total cycles in shared programs: 361468455 -> 361288721 (-0.05%)
cycles in affected programs: 197367688 -> 197187954 (-0.09%)
helped: 990
HURT: 683
helped stats (abs) min: 1 max: 119045 x̄: 806.00 x̃: 16
helped stats (rel) min: <.01% max: 38.56% x̄: 1.06% x̃: 0.26%
HURT stats (abs)   min: 1 max: 12190 x̄: 905.14 x̃: 22
HURT stats (rel)   min: <.01% max: 25.18% x̄: 1.16% x̃: 0.47%
95% mean confidence interval for cycles value: -315.45 100.58
95% mean confidence interval for cycles %-change: -0.31% <.01%
Inconclusive result (value mean confidence interval includes 0).

total spills in shared programs: 12147 -> 8948 (-26.34%)
spills in affected programs: 5433 -> 2234 (-58.88%)
helped: 343
HURT: 0

total fills in shared programs: 25262 -> 21814 (-13.65%)
fills in affected programs: 7771 -> 4323 (-44.37%)
helped: 343
HURT: 3

LOST:   0
GAINED: 17

Ivy Bridge
total instructions in shared programs: 12083517 -> 12081427 (-0.02%)
instructions in affected programs: 540744 -> 538654 (-0.39%)
helped: 786
HURT: 29
helped stats (abs) min: 1 max: 42 x̄: 2.70 x̃: 2
helped stats (rel) min: 0.06% max: 5.44% x̄: 0.55% x̃: 0.36%
HURT stats (abs)   min: 1 max: 1 x̄: 1.00 x̃: 1
HURT stats (rel)   min: 0.16% max: 0.95% x̄: 0.38% x̃: 0.31%
95% mean confidence interval for instructions value: -2.83 -2.30
95% mean confidence interval for instructions %-change: -0.57% -0.47%
Instructions are helped.

total cycles in shared programs: 180153463 -> 180124798 (-0.02%)
cycles in affected programs: 72597920 -> 72569255 (-0.04%)
helped: 572
HURT: 249
helped stats (abs) min: 1 max: 14830 x̄: 109.48 x̃: 13
helped stats (rel) min: <.01% max: 8.92% x̄: 0.71% x̃: 0.26%
HURT stats (abs)   min: 1 max: 11060 x̄: 136.37 x̃: 10
HURT stats (rel)   min: <.01% max: 10.85% x̄: 0.54% x̃: 0.32%
95% mean confidence interval for cycles value: -96.22 26.39
95% mean confidence interval for cycles %-change: -0.43% -0.23%
Inconclusive result (value mean confidence interval includes 0).

total spills in shared programs: 3625 -> 3623 (-0.06%)
spills in affected programs: 46 -> 44 (-4.35%)
helped: 1
HURT: 0

total fills in shared programs: 4065 -> 4061 (-0.10%)
fills in affected programs: 104 -> 100 (-3.85%)
helped: 1
HURT: 0

LOST:   0
GAINED: 8

Sandy Bridge
total instructions in shared programs: 10879656 -> 10878699 (<.01%)
instructions in affected programs: 275167 -> 274210 (-0.35%)
helped: 544
HURT: 0
helped stats (abs) min: 1 max: 20 x̄: 1.76 x̃: 1
helped stats (rel) min: 0.06% max: 3.11% x̄: 0.39% x̃: 0.25%
95% mean confidence interval for instructions value: -1.97 -1.55
95% mean confidence interval for instructions %-change: -0.43% -0.36%
Instructions are helped.

total cycles in shared programs: 154089096 -> 154081132 (<.01%)
cycles in affected programs: 4422722 -> 4414758 (-0.18%)
helped: 459
HURT: 214
helped stats (abs) min: 1 max: 258 x̄: 26.67 x̃: 8
helped stats (rel) min: <.01% max: 5.45% x̄: 0.51% x̃: 0.14%
HURT stats (abs)   min: 1 max: 226 x̄: 19.99 x̃: 4
HURT stats (rel)   min: <.01% max: 3.15% x̄: 0.34% x̃: 0.09%
95% mean confidence interval for cycles value: -15.51 -8.15
95% mean confidence interval for cycles %-change: -0.31% -0.17%
Cycles are helped.

total spills in shared programs: 2880 -> 2876 (-0.14%)
spills in affected programs: 636 -> 632 (-0.63%)
helped: 2
HURT: 0

total fills in shared programs: 3161 -> 3157 (-0.13%)
fills in affected programs: 1519 -> 1515 (-0.26%)
helped: 2
HURT: 0

LOST:   0
GAINED: 2

Iron Lake and GM45 had similar results. (Iron Lake shown)
total instructions in shared programs: 8157361 -> 8155067 (-0.03%)
instructions in affected programs: 382491 -> 380197 (-0.60%)
helped: 677
HURT: 0
helped stats (abs) min: 1 max: 43 x̄: 3.39 x̃: 2
helped stats (rel) min: 0.09% max: 5.19% x̄: 0.66% x̃: 0.42%
95% mean confidence interval for instructions value: -3.76 -3.01
95% mean confidence interval for instructions %-change: -0.72% -0.59%
Instructions are helped.

total cycles in shared programs: 188588292 -> 188583040 (<.01%)
cycles in affected programs: 3155064 -> 3149812 (-0.17%)
helped: 377
HURT: 13
helped stats (abs) min: 2 max: 180 x̄: 14.13 x̃: 6
helped stats (rel) min: <.01% max: 3.96% x̄: 0.39% x̃: 0.12%
HURT stats (abs)   min: 2 max: 8 x̄: 5.85 x̃: 6
HURT stats (rel)   min: <.01% max: 0.22% x̄: 0.06% x̃: 0.04%
95% mean confidence interval for cycles value: -15.67 -11.27
95% mean confidence interval for cycles %-change: -0.45% -0.30%
Cycles are helped.

Reviewed-by: Matt Turner <mattst88@gmail.com>

diff --git a/src/intel/compiler/brw_nir.c b/src/intel/compiler/brw_nir.c
index 50d6e48f50d5abe94abcadfdd5cf38be3adb075d..b9642bbb4174981dc23117c5668b02326c120535 100644 (file)
--- a/src/intel/compiler/brw_nir.c
+++ b/src/intel/compiler/brw_nir.c
@@ -963,6 +963,9 @@ brw_postprocess_nir(nir_shader *nir, const struct brw_compiler *compiler,
 
    OPT(nir_opt_dce);
 
+   if (OPT(nir_opt_rematerialize_compares))
+      OPT(nir_opt_dce);
+
    /* This is the last pass we run before we start emitting stuff.  It
     * determines when we need to insert boolean resolves on Gen <= 5.  We
     * run it last because it stashes data in instr->pass_flags and we don't