etnaviv: nir: add etna_nir_lower_to_source_mods(..)

This is more or less a copy of nir_lower_to_source_mods(..) with
the following differences:

 - we store the source mods in pass_flags
 - we do not try to saturate the destination

Signed-off-by: Christian Gmeiner <cgmeiner@igalia.com>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24216>

src/gallium/drivers/etnaviv/etnaviv_nir.h

@@ -37,6 +37,9 @@ etna_lower_alu(nir_shader *shader, bool has_new_transcendentals);
 bool
 etna_nir_lower_texture(nir_shader *s, struct etna_shader_key *key);
 
+bool
+etna_nir_lower_to_source_mods(nir_shader *shader);
+
 bool
 etna_nir_lower_ubo_to_uniform(nir_shader *shader);
 

src/gallium/drivers/etnaviv/etnaviv_nir_lower_source_mods.c

@@ -0,0 +1,124 @@
+/*
+ * Copyright © 2014 Intel Corporation
+ * Copyright © 2023 Igalia S.L.
+ *
+ * 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.
+ */
+
+#include "etnaviv_nir.h"
+#include "etnaviv_compiler_nir.h"
+
+/*
+ * This pass lowers the neg and abs operations to pass_flags on
+ * ALU operations.
+ */
+
+static void
+alu_src_consume_abs(nir_instr *instr, unsigned idx)
+{
+   set_src_mod_abs(instr, idx);
+}
+
+static void
+alu_src_consume_negate(nir_instr *instr, unsigned idx)
+{
+   /* If abs is set on the source, the negate goes away */
+   if (!is_src_mod_abs(instr, idx))
+      toggle_src_mod_neg(instr, idx);
+}
+
+static bool
+nir_lower_to_source_mods_instr(nir_builder *b, nir_instr *instr,
+                               void *data)
+{
+   bool progress = false;
+
+   if (instr->type != nir_instr_type_alu)
+      return false;
+
+   nir_alu_instr *alu = nir_instr_as_alu(instr);
+
+   for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; i++) {
+      if (!alu->src[i].src.is_ssa)
+         continue;
+
+      if (alu->src[i].src.ssa->parent_instr->type != nir_instr_type_alu)
+         continue;
+
+      nir_alu_instr *parent = nir_instr_as_alu(alu->src[i].src.ssa->parent_instr);
+
+      if (parent->dest.saturate)
+         continue;
+
+      if (nir_alu_type_get_base_type(nir_op_infos[alu->op].input_types[i]) != nir_type_float)
+         continue;
+
+      if (!(parent->op == nir_op_fabs) &&
+          !(parent->op == nir_op_fneg)) {
+         continue;
+      }
+
+      if (nir_src_bit_size(alu->src[i].src) == 64)
+         continue;
+
+      /* We can only store up to 3 source modifiers. */
+      if (i >= 3)
+         continue;
+
+      nir_instr_rewrite_src(instr, &alu->src[i].src, parent->src[0].src);
+
+      /* Apply any modifiers that come from the parent opcode */
+      if (parent->op == nir_op_fneg)
+         alu_src_consume_negate(instr, i);
+      if (parent->op == nir_op_fabs)
+         alu_src_consume_abs(instr, i);
+
+      /* Apply modifiers from the parent source */
+      if (parent->src[0].negate || is_src_mod_neg(&parent->instr, 0))
+         alu_src_consume_negate(instr, i);
+      if (parent->src[0].abs || is_src_mod_abs(&parent->instr, 0))
+         alu_src_consume_abs(instr, i);
+
+      for (int j = 0; j < 4; ++j) {
+         if (!nir_alu_instr_channel_used(alu, i, j))
+            continue;
+         alu->src[i].swizzle[j] = parent->src[0].swizzle[alu->src[i].swizzle[j]];
+      }
+
+      if (nir_ssa_def_is_unused(&parent->dest.dest.ssa))
+         nir_instr_remove(&parent->instr);
+
+      progress = true;
+   }
+
+   return progress;
+}
+
+bool
+etna_nir_lower_to_source_mods(nir_shader *shader)
+{
+   nir_shader_clear_pass_flags(shader);
+
+   return nir_shader_instructions_pass(shader,
+                                       nir_lower_to_source_mods_instr,
+                                       nir_metadata_block_index |
+                                       nir_metadata_dominance,
+                                       NULL);
+}

src/gallium/drivers/etnaviv/meson.build

@@ -57,6 +57,7 @@ files_etnaviv = files(
   'etnaviv_format.c',
   'etnaviv_format.h',
   'etnaviv_internal.h',
+  'etnaviv_nir_lower_source_mods.c',
   'etnaviv_nir_lower_texture.c',
   'etnaviv_nir_lower_ubo_to_uniform.c',
   'etnaviv_nir.c',