From: Ian Romanick <ian.d.roman...@intel.com>
shader-db results:
All Gen7+ platforms had similar results. (Skylake shown)
total instructions in shared programs: 15106023 -> 15105981 (<.01%)
instructions in affected programs: 300 -> 258 (-14.00%)
helped: 6
HURT: 0
helped stats (abs) min: 7 max: 7 x̄: 7.00 x̃: 7
helped stats (rel) min: 14.00% max: 14.00% x̄: 14.00% x̃: 14.00%
95% mean confidence interval for instructions value: -7.00 -7.00
95% mean confidence interval for instructions %-change: -14.00% -14.00%
Instructions are helped.
total cycles in shared programs: 566050327 -> 566050075 (<.01%)
cycles in affected programs: 2826 -> 2574 (-8.92%)
helped: 6
HURT: 0
helped stats (abs) min: 40 max: 44 x̄: 42.00 x̃: 42
helped stats (rel) min: 8.89% max: 8.94% x̄: 8.92% x̃: 8.92%
95% mean confidence interval for cycles value: -44.30 -39.70
95% mean confidence interval for cycles %-change: -8.95% -8.88%
Cycles are helped.
No changes on Gen6 or earlier.
Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
---
src/compiler/nir/nir_opt_algebraic.py | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/src/compiler/nir/nir_opt_algebraic.py
b/src/compiler/nir/nir_opt_algebraic.py
index ae1261f8744..3267e93a583 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -105,6 +105,11 @@ optimizations = [
(('imul', a, 1), a),
(('fmul', a, -1.0), ('fneg', a)),
(('imul', a, -1), ('ineg', a)),
+ # If a < 0: fsign(a)*a*a => -1*a*a => -a*a => abs(a)*a
+ # If a > 0: fsign(a)*a*a => 1*a*a => a*a => abs(a)*a
+ # If a == 0: fsign(a)*a*a => 0*0*0 => abs(0)*0
+ (('fmul', ('fsign', a), ('fmul', a, a)), ('fmul', ('fabs', a), a)),
+ (('fmul', ('fmul', ('fsign', a), a), a), ('fmul', ('fabs', a), a)),
(('~ffma', 0.0, a, b), b),
(('~ffma', a, 0.0, b), b),
(('~ffma', a, b, 0.0), ('fmul', a, b)),
--
2.14.4
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