diff options
| author | Ian Romanick <[email protected]> | 2018-07-26 18:26:18 -0700 |
|---|---|---|
| committer | Ian Romanick <[email protected]> | 2018-08-04 01:12:03 -0700 |
| commit | be7d3ba34ab837488f5333edfd06dc08c8b37d3e (patch) | |
| tree | 76e3e86aa91a4f3c6f18fc9846eb89a9c307c033 /src/compiler/nir | |
| parent | d49eab27573024699dd288f194a3ced4be16671a (diff) | |
nir: Transform -fabs(a) < 0 to a != 0
Unlike the much older -abs(a) >= 0.0 transformation, this is not
precise. The behavior changes if a is NaN.
All Gen platforms had pretty similar results. (Skylake shown)
total instructions in shared programs: 14277216 -> 14277184 (<.01%)
instructions in affected programs: 2300 -> 2268 (-1.39%)
helped: 8
HURT: 0
helped stats (abs) min: 1 max: 8 x̄: 4.00 x̃: 3
helped stats (rel) min: 0.48% max: 15.15% x̄: 4.41% x̃: 1.01%
95% mean confidence interval for instructions value: -6.45 -1.55
95% mean confidence interval for instructions %-change: -9.96% 1.13%
Inconclusive result (%-change mean confidence interval includes 0).
total cycles in shared programs: 532577848 -> 532577990 (<.01%)
cycles in affected programs: 17486 -> 17628 (0.81%)
helped: 2
HURT: 5
helped stats (abs) min: 2 max: 6 x̄: 4.00 x̃: 4
helped stats (rel) min: 0.06% max: 1.81% x̄: 0.93% x̃: 0.93%
HURT stats (abs) min: 6 max: 50 x̄: 30.00 x̃: 26
HURT stats (rel) min: 0.55% max: 2.17% x̄: 1.19% x̃: 1.02%
95% mean confidence interval for cycles value: -1.06 41.63
95% mean confidence interval for cycles %-change: -0.58% 1.74%
Inconclusive result (value mean confidence interval includes 0).
Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Thomas Helland <[email protected]>
Diffstat (limited to 'src/compiler/nir')
| -rw-r--r-- | src/compiler/nir/nir_opt_algebraic.py | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index b96a7f93c08..8300d6d01f5 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -212,6 +212,10 @@ optimizations = [ # a != 0.0 (('~flt', 0.0, ('fabs', a)), ('fne', a, 0.0)), + # -fabs(a) < 0.0 + # fabs(a) > 0.0 + (('~flt', ('fneg', ('fabs', a)), 0.0), ('fne', a, 0.0)), + (('fmax', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('ior', a, b))), (('fmax', ('fneg(is_used_once)', ('b2f(is_used_once)', a)), ('fneg', ('b2f', b))), ('fneg', ('b2f', ('ior', a, b)))), (('fmin', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('iand', a, b))), |