brw: replace lower_fs_msaa with nir_inline_sysval

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Marek Olšák <maraeo@gmail.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36516>

src/intel/compiler/brw_compile_fs.cpp

@@ -1528,7 +1528,27 @@ brw_compile_fs(const struct brw_compiler *compiler,
    }
 
    NIR_PASS(_, nir, brw_nir_move_interpolation_to_top);
-   NIR_PASS(_, nir, brw_nir_lower_fs_msaa, key);
+
+   if (!brw_wm_prog_key_is_dynamic(key)) {
+      uint32_t f = 0;
+
+      if (key->multisample_fbo == INTEL_ALWAYS)
+         f |= INTEL_MSAA_FLAG_MULTISAMPLE_FBO;
+
+      if (key->alpha_to_coverage == INTEL_ALWAYS)
+         f |= INTEL_MSAA_FLAG_ALPHA_TO_COVERAGE;
+
+      if (key->provoking_vertex_last == INTEL_ALWAYS)
+         f |= INTEL_MSAA_FLAG_PROVOKING_VERTEX_LAST;
+
+      if (key->persample_interp == INTEL_ALWAYS) {
+         f |= INTEL_MSAA_FLAG_PERSAMPLE_DISPATCH |
+              INTEL_MSAA_FLAG_PERSAMPLE_INTERP;
+      }
+
+      NIR_PASS(_, nir, nir_inline_sysval, nir_intrinsic_load_fs_msaa_intel, f);
+   }
+
    brw_postprocess_nir(nir, compiler, debug_enabled,
                        key->base.robust_flags);
 

src/intel/compiler/brw_nir.h

@@ -178,8 +178,6 @@ bool brw_nir_lower_cs_intrinsics(nir_shader *nir,
 bool brw_nir_lower_alpha_to_coverage(nir_shader *shader);
 bool brw_needs_vertex_attributes_bypass(const nir_shader *shader);
 void brw_nir_lower_fs_barycentrics(nir_shader *shader);
-bool brw_nir_lower_fs_msaa(nir_shader *shader,
-                           const struct brw_wm_prog_key *key);
 
 void brw_nir_lower_vs_inputs(nir_shader *nir);
 void brw_nir_lower_vue_inputs(nir_shader *nir,

src/intel/compiler/brw_nir_lower_fs_msaa.c

@@ -1,50 +0,0 @@
-/*
- * Copyright (c) 2025 Intel Corporation
- * SPDX-License-Identifier: MIT
- */
-
-#include "compiler/nir/nir_builder.h"
-#include "brw_nir.h"
-
-static bool
-brw_nir_lower_fs_msaa_intel_instr(nir_builder *b,
-                                  nir_intrinsic_instr *intrin,
-                                  void *data)
-{
-   if (intrin->intrinsic != nir_intrinsic_load_fs_msaa_intel)
-      return false;
-
-   b->cursor = nir_before_instr(&intrin->instr);
-
-   const struct brw_wm_prog_key *key = data;
-
-   uint32_t fs_msaa_flags =
-      (key->multisample_fbo == INTEL_ALWAYS ?
-       INTEL_MSAA_FLAG_MULTISAMPLE_FBO : 0) |
-      (key->persample_interp == INTEL_ALWAYS ?
-       (INTEL_MSAA_FLAG_PERSAMPLE_DISPATCH |
-        INTEL_MSAA_FLAG_PERSAMPLE_INTERP) : 0) |
-      (key->alpha_to_coverage == INTEL_ALWAYS ?
-       INTEL_MSAA_FLAG_ALPHA_TO_COVERAGE : 0) |
-      (key->provoking_vertex_last == INTEL_ALWAYS ?
-       INTEL_MSAA_FLAG_PROVOKING_VERTEX_LAST : 0);
-
-   nir_def_replace(&intrin->def, nir_imm_int(b, fs_msaa_flags));
-
-   return true;
-}
-
-bool
-brw_nir_lower_fs_msaa(nir_shader *shader,
-                      const struct brw_wm_prog_key *key)
-{
-   if (brw_wm_prog_key_is_dynamic(key))
-      return false;
-
-   return nir_shader_intrinsics_pass(shader,
-                                     brw_nir_lower_fs_msaa_intel_instr,
-                                     nir_metadata_control_flow |
-                                     nir_metadata_live_defs |
-                                     nir_metadata_divergence,
-                                     (void *)key);
-}

src/intel/compiler/meson.build

@@ -73,7 +73,6 @@ libintel_compiler_brw_files = files(
   'brw_nir_lower_cs_intrinsics.c',
   'brw_nir_lower_alpha_to_coverage.c',
   'brw_nir_lower_fs_barycentrics.c',
-  'brw_nir_lower_fs_msaa.c',
   'brw_nir_lower_immediate_offsets.c',
   'brw_nir_lower_intersection_shader.c',
   'brw_nir_lower_ray_queries.c',