From 6d52e6fd2c53355ee67d4da7518b2c59d90598eb Mon Sep 17 00:00:00 2001
From: Emma Anholt <emma@anholt.net>
Date: Wed, 22 Feb 2023 12:59:16 -0800
Subject: [PATCH] nir: Port a floor->truncate algebraic opt pattern from GLSL.
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

Prevents regression when dropping code from the GLSL optimizer.

Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21475>
---
 src/compiler/nir/nir_opt_algebraic.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 072b992..9d2fbb5 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -129,6 +129,8 @@ optimizations = [
     '!options->lower_bitops'),
    (('irem', a, '#b(is_neg_power_of_two)'), ('irem', a, ('iabs', b)), '!options->lower_bitops'),
 
+   (('~fmul', ('fsign', a), ('ffloor', ('fadd', ('fabs', a), 0.5))), ('ftrunc', ('fadd', a, ('fmul', ('fsign', a), 0.5))), '!options->lower_ftrunc || options->lower_ffloor'),
+
    (('~fneg', ('fneg', a)), a),
    (('ineg', ('ineg', a)), a),
    (('fabs', ('fneg', a)), ('fabs', a)),
-- 
2.7.4