pan/bi: Import algebraic pass from midgard

We'll need some of these at least.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4139>

src/panfrost/bifrost/bifrost_compile.c

@@ -32,6 +32,7 @@
 
 #include "disassemble.h"
 #include "bifrost_compile.h"
+#include "bifrost_nir.h"
 #include "compiler.h"
 #include "bi_quirks.h"
 #include "bi_print.h"
@@ -708,6 +709,7 @@ bi_optimize_nir(nir_shader *nir)
         } while (progress);
 
         NIR_PASS(progress, nir, nir_opt_algebraic_late);
+        NIR_PASS(progress, nir, bifrost_nir_lower_algebraic_late);
         NIR_PASS(progress, nir, nir_lower_alu_to_scalar, NULL, NULL);
         NIR_PASS(progress, nir, nir_lower_load_const_to_scalar);
 

src/panfrost/bifrost/bifrost_nir.h

@@ -0,0 +1,4 @@
+#include <stdbool.h>
+#include "nir.h"
+
+bool bifrost_nir_lower_algebraic_late(nir_shader *shader);

src/panfrost/bifrost/bifrost_nir_algebraic.py

@@ -0,0 +1,97 @@
+#
+# Copyright (C) 2020 Collabora, Ltd.
+# Copyright (C) 2018 Alyssa Rosenzweig
+# Copyright (C) 2016 Intel Corporation
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice (including the next
+# paragraph) shall be included in all copies or substantial portions of the
+# Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+
+import argparse
+import sys
+import math
+
+a = 'a'
+b = 'b'
+c = 'c'
+
+algebraic_late = [
+    # ineg must be lowered late, but only for integers; floats will try to
+    # have modifiers attached... hence why this has to be here rather than
+    # a more standard lower_negate approach
+
+    (('ineg', a), ('isub', 0, a)),
+]
+
+
+# Midgard is able to type convert down by only one "step" per instruction; if
+# NIR wants more than one step, we need to break up into multiple instructions
+
+converts = []
+
+for op in ('u2u', 'i2i', 'f2f', 'i2f', 'u2f', 'f2i', 'f2u'):
+    srcsz_max = 64
+    dstsz_max = 64
+    # 8 bit float doesn't exist
+    srcsz_min = 8 if op[0] != 'f' else 16
+    dstsz_min = 8 if op[2] != 'f' else 16
+    dstsz = dstsz_min
+    # Iterate over all possible destination and source sizes
+    while dstsz <= dstsz_max:
+        srcsz = srcsz_min
+        while srcsz <= srcsz_max:
+            # Size converter lowering is only needed if src and dst sizes are
+            # spaced by a factor > 2.
+            # Type converter lowering is needed as soon as src_size != dst_size
+            if srcsz != dstsz and ((srcsz * 2 != dstsz and srcsz != dstsz * 2) or op[0] != op[2]):
+                cursz = srcsz
+                rule = a
+                # When converting down we first do the type conversion followed
+                # by one or more size conversions. When converting up, we do
+                # the type conversion at the end. This way we don't have to
+                # deal with the fact that f2f8 doesn't exists.
+                sizeconvop = op[0] + '2' + op[0] if srcsz < dstsz else op[2] + '2' + op[2]
+                if srcsz > dstsz and op[0] != op[2]:
+                    rule = (op + str(int(cursz)), rule)
+                while cursz != dstsz:
+                    cursz = cursz / 2 if dstsz < srcsz else cursz * 2
+                    rule = (sizeconvop + str(int(cursz)), rule)
+                if srcsz < dstsz and op[0] != op[2]:
+                    rule = (op + str(int(cursz)), rule)
+                converts += [((op + str(int(dstsz)), 'a@' + str(int(srcsz))), rule)]
+            srcsz *= 2
+        dstsz *= 2
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-p', '--import-path', required=True)
+    args = parser.parse_args()
+    sys.path.insert(0, args.import_path)
+    run()
+
+
+def run():
+    import nir_algebraic  # pylint: disable=import-error
+
+    print('#include "bifrost_nir.h"')
+
+    print(nir_algebraic.AlgebraicPass("bifrost_nir_lower_algebraic_late",
+                                      algebraic_late + converts).render())
+
+if __name__ == '__main__':
+    main()

src/panfrost/bifrost/meson.build

@@ -28,9 +28,21 @@ libpanfrost_bifrost_files = files(
   'bifrost_compile.c',
 )
 
+bifrost_nir_algebraic_c = custom_target(
+  'bifrost_nir_algebraic.c',
+  input : 'bifrost_nir_algebraic.py',
+  output : 'bifrost_nir_algebraic.c',
+  command : [
+    prog_python, '@INPUT@',
+    '-p', join_paths(meson.source_root(), 'src/compiler/nir/'),
+  ],
+  capture : true,
+  depend_files : nir_algebraic_py,
+)
+
 libpanfrost_bifrost = static_library(
   'panfrost_bifrost',
-  [libpanfrost_bifrost_files],
+  [libpanfrost_bifrost_files, bifrost_nir_algebraic_c],
   include_directories : [inc_common, inc_include, inc_src],
   dependencies: [idep_nir],
   link_with: [libpanfrost_util],