agx: Add simple image fencing pass

Minimum needed to pass CTS.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24258>

src/asahi/compiler/agx_nir.h

@@ -12,5 +12,6 @@ struct nir_shader;
 bool agx_nir_opt_ixor_bcsel(struct nir_shader *shader);
 bool agx_nir_lower_algebraic_late(struct nir_shader *shader);
 bool agx_nir_fuse_algebraic_late(struct nir_shader *shader);
+bool agx_nir_fence_images(struct nir_shader *shader);
 
 #endif

src/asahi/compiler/agx_nir_fence_images.c

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2023 Valve Corporation
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "compiler/nir/nir_builder.h"
+#include "agx_nir.h"
+#include "nir.h"
+#include "nir_builder_opcodes.h"
+#include "nir_intrinsics.h"
+
+static bool
+pass(struct nir_builder *b, nir_instr *instr, void *data)
+{
+   if (instr->type != nir_instr_type_intrinsic)
+      return false;
+
+   b->cursor = nir_after_instr(instr);
+
+   nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
+   switch (intr->intrinsic) {
+   case nir_intrinsic_image_store:
+   case nir_intrinsic_bindless_image_store:
+      nir_fence_pbe_to_tex_agx(b);
+      return true;
+
+   case nir_intrinsic_image_atomic:
+   case nir_intrinsic_bindless_image_atomic:
+   case nir_intrinsic_image_atomic_swap:
+   case nir_intrinsic_bindless_image_atomic_swap:
+      nir_fence_mem_to_tex_agx(b);
+      return true;
+
+   default:
+      return false;
+   }
+}
+
+bool
+agx_nir_fence_images(nir_shader *s)
+{
+   return nir_shader_instructions_pass(
+      s, pass, nir_metadata_block_index | nir_metadata_dominance, NULL);
+}

src/asahi/compiler/agx_nir_lower_texture.c

@@ -10,6 +10,7 @@
 #include "compiler/nir/nir_builtin_builder.h"
 #include "agx_compiler.h"
 #include "agx_internal_formats.h"
+#include "agx_nir.h"
 #include "nir_builder_opcodes.h"
 #include "nir_intrinsics.h"
 #include "nir_intrinsics_indices.h"
@@ -772,6 +773,12 @@ agx_nir_lower_texture(nir_shader *s, bool support_lod_bias)
    };
 
    NIR_PASS(progress, s, nir_lower_tex, &lower_tex_options);
+
+   /* Insert fences before lowering image atomics, since image atomics need
+    * different fencing than other image operations.
+    */
+   NIR_PASS(progress, s, agx_nir_fence_images);
+
    NIR_PASS(progress, s, nir_lower_image_atomics_to_global);
 
    /* Lower bias after nir_lower_tex (to get rid of txd) but before

src/asahi/compiler/meson.build

@@ -7,6 +7,7 @@ libasahi_agx_files = files(
   'agx_dce.c',
   'agx_liveness.c',
   'agx_insert_waits.c',
+  'agx_nir_fence_images.c',
   'agx_nir_lower_address.c',
   'agx_nir_lower_frag_sidefx.c',
   'agx_nir_lower_sample_mask.c',