From: Jason Ekstrand <jason.ekstrand@intel.com>
Date: Thu, 6 Dec 2018 19:02:01 +0000 (-0600)
Subject: nir/algebraic: Optimize x2b(xneg(a)) -> a
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4bb1a34727f52ecd4a8f00725d740ae2047cb1dc;p=mesa.git

nir/algebraic: Optimize x2b(xneg(a)) -> a

Shader-db results on Kaby Lake:

    total instructions in shared programs: 15072525 -> 15072525 (0.00%)
    instructions in affected programs: 0 -> 0
    helped: 0
    HURT: 0

This helps prevent regressions in later commits.

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Tested-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
---

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 28e8a96d4d5..ea24094a927 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -85,6 +85,8 @@ optimizations = [
    (('fabs', ('u2f', a)), ('u2f', a)),
    (('iabs', ('iabs', a)), ('iabs', a)),
    (('iabs', ('ineg', a)), ('iabs', a)),
+   (('f2b', ('fneg', a)), ('f2b', a)),
+   (('i2b', ('ineg', a)), ('i2b', a)),
    (('~fadd', a, 0.0), a),
    (('iadd', a, 0), a),
    (('usadd_4x8', a, 0), a),