nir/algebraic: Simplify logic to detect sign of an integer

This occurs in a handful of places in the soft-fp64 code, and that is
the primary reason for the change.

v2: Fix a typo in a comment.  Noticed by Matt.  Copy the correct fp64
shader-db results to the commit message.  I realized that I used
accidentally used the results from the next commit.

Results on the 308 shaders extracted from the fp64 portion of the OpenGL
CTS:

Tiger Lake and Ice Lake had similar results. (Tiger Lake shown)
total instructions in shared programs: 906235 -> 906149 (<.01%)
instructions in affected programs: 353966 -> 353880 (-0.02%)
helped: 31
HURT: 2
helped stats (abs) min: 1 max: 8 x̄: 3.03 x̃: 3
helped stats (rel) min: 0.01% max: 1.59% x̄: 0.10% x̃: 0.04%
HURT stats (abs)   min: 3 max: 5 x̄: 4.00 x̃: 4
HURT stats (rel)   min: 0.02% max: 0.02% x̄: 0.02% x̃: 0.02%
95% mean confidence interval for instructions value: -3.51 -1.70
95% mean confidence interval for instructions %-change: -0.19% <.01%
Inconclusive result (%-change mean confidence interval includes 0).

total cycles in shared programs: 7076552 -> 7076173 (<.01%)
cycles in affected programs: 2878361 -> 2877982 (-0.01%)
helped: 37
HURT: 2
helped stats (abs) min: 2 max: 48 x̄: 10.81 x̃: 6
helped stats (rel) min: <.01% max: 2.17% x̄: 0.47% x̃: 0.01%
HURT stats (abs)   min: 1 max: 20 x̄: 10.50 x̃: 10
HURT stats (rel)   min: <.01% max: 0.01% x̄: <.01% x̃: <.01%
95% mean confidence interval for cycles value: -13.96 -5.48
95% mean confidence interval for cycles %-change: -0.72% -0.16%
Cycles are helped.

total fills in shared programs: 2064 -> 2065 (0.05%)
fills in affected programs: 45 -> 46 (2.22%)
helped: 0
HURT: 1

Regular shader-db results:

All Gen7+ platforms had similar results. (Tiger Lake shown)
total instructions in shared programs: 17611530 -> 17611506 (<.01%)
instructions in affected programs: 5934 -> 5910 (-0.40%)
helped: 10
HURT: 0
helped stats (abs) min: 1 max: 5 x̄: 2.40 x̃: 2
helped stats (rel) min: 0.14% max: 1.24% x̄: 0.47% x̃: 0.34%
95% mean confidence interval for instructions value: -3.53 -1.27
95% mean confidence interval for instructions %-change: -0.78% -0.17%
Instructions are helped.

total cycles in shared programs: 338419178 -> 338419218 (<.01%)
cycles in affected programs: 19244 -> 19284 (0.21%)
helped: 4
HURT: 2
helped stats (abs) min: 2 max: 4 x̄: 3.00 x̃: 3
helped stats (rel) min: 0.05% max: 0.11% x̄: 0.08% x̃: 0.08%
HURT stats (abs)   min: 26 max: 26 x̄: 26.00 x̃: 26
HURT stats (rel)   min: 1.20% max: 1.20% x̄: 1.20% x̃: 1.20%
95% mean confidence interval for cycles value: -9.08 22.41
95% mean confidence interval for cycles %-change: -0.35% 1.04%
Inconclusive result (value mean confidence interval includes 0).

No changes on any earlier Intel platform.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4142>
This commit is contained in:
Ian Romanick 2020-03-03 10:51:59 -08:00 committed by Marge Bot
parent e7f3a8d695
commit 88eb8f190b

View file

@ -497,6 +497,21 @@ optimizations.extend([
(('umin', ('umin', a, b), b), ('umin', a, b)), (('umin', ('umin', a, b), b), ('umin', a, b)),
(('imin', ('imin', a, b), b), ('imin', a, b)), (('imin', ('imin', a, b), b), ('imin', a, b)),
(('iand@32', a, ('inot', ('ishr', a, 31))), ('imax', a, 0)), (('iand@32', a, ('inot', ('ishr', a, 31))), ('imax', a, 0)),
# Simplify logic to detect sign of an integer.
(('ieq', ('iand', a, 0x80000000), 0x00000000), ('ige', a, 0)),
(('ine', ('iand', a, 0x80000000), 0x80000000), ('ige', a, 0)),
(('ine', ('iand', a, 0x80000000), 0x00000000), ('ilt', a, 0)),
(('ieq', ('iand', a, 0x80000000), 0x80000000), ('ilt', a, 0)),
(('ine', ('ushr', 'a@32', 31), 0), ('ilt', a, 0)),
(('ieq', ('ushr', 'a@32', 31), 0), ('ige', a, 0)),
(('ieq', ('ushr', 'a@32', 31), 1), ('ilt', a, 0)),
(('ine', ('ushr', 'a@32', 31), 1), ('ige', a, 0)),
(('ine', ('ishr', 'a@32', 31), 0), ('ilt', a, 0)),
(('ieq', ('ishr', 'a@32', 31), 0), ('ige', a, 0)),
(('ieq', ('ishr', 'a@32', 31), -1), ('ilt', a, 0)),
(('ine', ('ishr', 'a@32', 31), -1), ('ige', a, 0)),
(('fmin', a, ('fneg', a)), ('fneg', ('fabs', a))), (('fmin', a, ('fneg', a)), ('fneg', ('fabs', a))),
(('imin', a, ('ineg', a)), ('ineg', ('iabs', a))), (('imin', a, ('ineg', a)), ('ineg', ('iabs', a))),
(('fmin', a, ('fneg', ('fabs', a))), ('fneg', ('fabs', a))), (('fmin', a, ('fneg', ('fabs', a))), ('fneg', ('fabs', a))),