nir/lower_input_attachments: Refactor to use an options struct

While we're at it, fold the details of how to load the fragcoord into
load_fragcoord().

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5719>

src/amd/vulkan/radv_shader.c

@@ -505,7 +505,10 @@ radv_shader_compile_to_nir(struct radv_device *device,
 		    !radv_use_llvm_for_stage(device, nir->info.stage))
                         NIR_PASS_V(nir, nir_lower_io_to_vector, nir_var_shader_out);
 		if (nir->info.stage == MESA_SHADER_FRAGMENT)
-			NIR_PASS_V(nir, nir_lower_input_attachments, true);
+			NIR_PASS_V(nir, nir_lower_input_attachments,
+				   &(nir_input_attachment_options) {
+					.use_fragcoord_sysval = true,
+				   });
 
 		NIR_PASS_V(nir, nir_remove_dead_variables,
 		           nir_var_shader_in | nir_var_shader_out | nir_var_system_value | nir_var_mem_shared,

src/compiler/nir/nir.h

@@ -4458,7 +4458,12 @@ enum nir_lower_idiv_path {
 
 bool nir_lower_idiv(nir_shader *shader, enum nir_lower_idiv_path path);
 
-bool nir_lower_input_attachments(nir_shader *shader, bool use_fragcoord_sysval);
+typedef struct nir_input_attachment_options {
+   bool use_fragcoord_sysval;
+} nir_input_attachment_options;
+
+bool nir_lower_input_attachments(nir_shader *shader,
+                                 const nir_input_attachment_options *options);
 
 bool nir_lower_clip_vs(nir_shader *shader, unsigned ucp_enables,
                        bool use_vars,

src/compiler/nir/nir_lower_input_attachments.c

@@ -25,8 +25,11 @@
 #include "nir_builder.h"
 
 static nir_ssa_def *
-load_frag_coord(nir_builder *b)
+load_frag_coord(const nir_input_attachment_options *options, nir_builder *b)
 {
+   if (options->use_fragcoord_sysval)
+      return nir_load_frag_coord(b);
+
    nir_variable *pos =
       nir_find_variable_with_location(b->shader, nir_var_shader_in,
                                       VARYING_SLOT_POS);
@@ -49,7 +52,7 @@ load_frag_coord(nir_builder *b)
 
 static bool
 try_lower_input_load(nir_function_impl *impl, nir_intrinsic_instr *load,
-                     bool use_fragcoord_sysval)
+                     const nir_input_attachment_options *options)
 {
    nir_deref_instr *deref = nir_src_as_deref(load->src[0]);
    assert(glsl_type_is_image(deref->type));
@@ -65,8 +68,7 @@ try_lower_input_load(nir_function_impl *impl, nir_intrinsic_instr *load,
    nir_builder_init(&b, impl);
    b.cursor = nir_instr_remove(&load->instr);
 
-   nir_ssa_def *frag_coord = use_fragcoord_sysval ? nir_load_frag_coord(&b)
+   nir_ssa_def *frag_coord = load_frag_coord(options, &b);
-                                                  : load_frag_coord(&b);
    frag_coord = nir_f2i32(&b, frag_coord);
    nir_ssa_def *offset = nir_ssa_for_src(&b, load->src[1], 2);
    nir_ssa_def *pos = nir_iadd(&b, frag_coord, offset);
@@ -128,7 +130,7 @@ try_lower_input_load(nir_function_impl *impl, nir_intrinsic_instr *load,
 
 static bool
 try_lower_input_texop(nir_function_impl *impl, nir_tex_instr *tex,
-							 bool use_fragcoord_sysval)
+                      const nir_input_attachment_options *options)
 {
    nir_deref_instr *deref = nir_src_as_deref(tex->src[0].src);
 
@@ -139,8 +141,7 @@ try_lower_input_texop(nir_function_impl *impl, nir_tex_instr *tex,
    nir_builder_init(&b, impl);
    b.cursor = nir_before_instr(&tex->instr);
 
-   nir_ssa_def *frag_coord = use_fragcoord_sysval ? nir_load_frag_coord(&b)
+   nir_ssa_def *frag_coord = load_frag_coord(options, &b);
-                                                  : load_frag_coord(&b);
    frag_coord = nir_f2i32(&b, frag_coord);
 
    nir_ssa_def *layer = nir_load_layer_id(&b);
@@ -155,7 +156,8 @@ try_lower_input_texop(nir_function_impl *impl, nir_tex_instr *tex,
 }
 
 bool
-nir_lower_input_attachments(nir_shader *shader, bool use_fragcoord_sysval)
+nir_lower_input_attachments(nir_shader *shader,
+                            const nir_input_attachment_options *options)
 {
    assert(shader->info.stage == MESA_SHADER_FRAGMENT);
    bool progress = false;
@@ -173,7 +175,7 @@ nir_lower_input_attachments(nir_shader *shader, bool use_fragcoord_sysval)
                if (tex->op == nir_texop_fragment_mask_fetch ||
                    tex->op == nir_texop_fragment_fetch) {
                   progress |= try_lower_input_texop(function->impl, tex,
-                                                    use_fragcoord_sysval);
+                                                    options);
                }
                break;
             }
@@ -182,7 +184,7 @@ nir_lower_input_attachments(nir_shader *shader, bool use_fragcoord_sysval)
 
                if (load->intrinsic == nir_intrinsic_image_deref_load) {
                   progress |= try_lower_input_load(function->impl, load,
-                                                   use_fragcoord_sysval);
+                                                   options);
                }
                break;
             }

src/freedreno/vulkan/tu_shader.c

@@ -770,8 +770,12 @@ tu_shader_create(struct tu_device *dev,
    NIR_PASS_V(nir, nir_lower_system_values);
    NIR_PASS_V(nir, nir_lower_frexp);
 
-   if (stage == MESA_SHADER_FRAGMENT)
+   if (stage == MESA_SHADER_FRAGMENT) {
-      NIR_PASS_V(nir, nir_lower_input_attachments, true);
+      NIR_PASS_V(nir, nir_lower_input_attachments,
+                 &(nir_input_attachment_options) {
+                     .use_fragcoord_sysval = true,
+                 });
+   }
 
    NIR_PASS_V(nir, nir_lower_explicit_io,
               nir_var_mem_ubo | nir_var_mem_ssbo,

src/intel/vulkan/anv_pipeline.c

@@ -744,7 +744,10 @@ anv_pipeline_lower_nir(struct anv_pipeline *pipeline,
    if (nir->info.stage == MESA_SHADER_FRAGMENT) {
       NIR_PASS_V(nir, nir_lower_wpos_center,
                  anv_pipeline_to_graphics(pipeline)->sample_shading_enable);
-      NIR_PASS_V(nir, nir_lower_input_attachments, true);
+      NIR_PASS_V(nir, nir_lower_input_attachments,
+                 &(nir_input_attachment_options) {
+                     .use_fragcoord_sysval = true,
+                 });
    }
 
    NIR_PASS_V(nir, anv_nir_lower_ycbcr_textures, layout);