Mesa (master): nir: add strength reduction pattern for imod/irem with pow2 divisor.

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Module: Mesa
Branch: master
Commit: 0ef5f3552f68076747211ec81f687b37a5540d8e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=0ef5f3552f68076747211ec81f687b37a5540d8e

Author: Daniel Schürmann <daniel.schuermann at campus.tu-berlin.de>
Date:   Wed Jan 30 11:04:55 2019 +0100

nir: add strength reduction pattern for imod/irem with pow2 divisor.

Affected games are Detroit : Become Human and Doom : Eternal.

Totals from 6262 (4.54% of 138013) affected shaders (RAVEN):
SGPRs: 678472 -> 678640 (+0.02%)
VGPRs: 498288 -> 498360 (+0.01%)
CodeSize: 67064196 -> 65926000 (-1.70%)
MaxWaves: 19390 -> 19382 (-0.04%)
Instrs: 13175372 -> 12932517 (-1.84%)
Cycles: 1444043256 -> 1443022576 (-0.07%); split: -0.08%, +0.01%
VMEM: 929560 -> 908726 (-2.24%); split: +0.39%, -2.63%
SMEM: 406207 -> 400062 (-1.51%); split: +0.46%, -1.97%
VClause: 215168 -> 215031 (-0.06%)
SClause: 443312 -> 442324 (-0.22%); split: -0.25%, +0.03%
Copies: 1350793 -> 1344326 (-0.48%); split: -0.52%, +0.04%
Branches: 506432 -> 506370 (-0.01%); split: -0.02%, +0.01%
PreSGPRs: 619652 -> 619619 (-0.01%)
PreVGPRs: 473212 -> 473168 (-0.01%)

Reviewed-by: Rhys Perry <pendingchaos02 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/175>

---

 src/compiler/nir/nir_opt_algebraic.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index cd52925972a..f70d29101b4 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -102,10 +102,17 @@ optimizations = [
    (('idiv', a, 1), a),
    (('umod', a, 1), 0),
    (('imod', a, 1), 0),
+   (('imod', a, -1), 0),
+   (('irem', a, 1), 0),
+   (('irem', a, -1), 0),
    (('udiv', a, '#b(is_pos_power_of_two)'), ('ushr', a, ('find_lsb', b)), '!options->lower_bitops'),
    (('idiv', a, '#b(is_pos_power_of_two)'), ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', b))), '!options->lower_bitops'),
    (('idiv', a, '#b(is_neg_power_of_two)'), ('ineg', ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', ('iabs', b))))), '!options->lower_bitops'),
    (('umod', a, '#b(is_pos_power_of_two)'),    ('iand', a, ('isub', b, 1))),
+   (('imod', a, '#b(is_pos_power_of_two)'),    ('iand', a, ('isub', b, 1))),
+   (('imod', a, '#b(is_neg_power_of_two)'),    ('ior', a, b)),
+   (('irem', a, '#b(is_pos_power_of_two)'),    ('bcsel', ('ige', a, 0), ('iand', a, ('isub', b, 1)), ('ior', a, ('ineg', b)))),
+   (('irem', a, '#b(is_neg_power_of_two)'),    ('bcsel', ('ige', a, 0), ('iand', a, ('inot', b)), ('ior', a, b))),
 
    (('~fneg', ('fneg', a)), a),
    (('ineg', ('ineg', a)), a),