[Mesa-dev] [PATCH 1/2] nir: optimize min(min(a, b), c) to min3(a, b, c) under an option

[Samuel Pitoiset]

Similar for max().

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/compiler/nir/nir.h                | 3 +++
 src/compiler/nir/nir_opt_algebraic.py | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index f6086bd6c0..04991b7d04 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -1897,6 +1897,9 @@ typedef struct nir_shader_compiler_options {
    /* lower b2f to iand */
    bool lower_b2f;
 
+   /* lower min(min(a, b), c) to min3(a, b, c) (same for max()). */
+   bool lower_minmax3;
+
    /* Does the native fdot instruction replicate its result for four
     * components?  If so, then opt_algebraic_late will turn all fdotN
     * instructions into fdot_replicatedN instructions.
diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 909ea3daf4..1d67e2d88c 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -224,6 +224,14 @@ optimizations = [
    (('imax', a, a), a),
    (('umin', a, a), a),
    (('umax', a, a), a),
+
+   (('fmin', ('fmin', a, b), c), ('fmin3', a, b, c), 'options->lower_minmax3'),
+   (('imin', ('imin', a, b), c), ('imin3', a, b, c), 'options->lower_minmax3'),
+   (('umin', ('umin', a, b), c), ('umin3', a, b, c), 'options->lower_minmax3'),
+   (('fmax', ('fmax', a, b), c), ('fmax3', a, b, c), 'options->lower_minmax3'),
+   (('imax', ('imax', a, b), c), ('imax3', a, b, c), 'options->lower_minmax3'),
+   (('umax', ('umax', a, b), c), ('umax3', a, b, c), 'options->lower_minmax3'),
+
    (('fmin', a, ('fneg', a)), ('fneg', ('fabs', a))),
    (('imin', a, ('ineg', a)), ('ineg', ('iabs', a))),
    (('fmin', a, ('fneg', ('fabs', a))), ('fneg', ('fabs', a))),
-- 
2.17.0