nir,nak: Add a nir_texop_sample_pos_nv and plumb it through

Reviewed-by: Mary Guillemard <mary.guillemard@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36207>

src/compiler/nir/nir.c

@@ -3237,6 +3237,7 @@ nir_tex_instr_result_size(const nir_tex_instr *instr)
 
    case nir_texop_hdr_dim_nv:
    case nir_texop_tex_type_nv:
+   case nir_texop_sample_pos_nv:
       return 4;
 
    case nir_texop_custom_border_color_agx:
@@ -3266,6 +3267,7 @@ nir_tex_instr_is_query(const nir_tex_instr *instr)
    case nir_texop_has_custom_border_color_agx:
    case nir_texop_hdr_dim_nv:
    case nir_texop_tex_type_nv:
+   case nir_texop_sample_pos_nv:
       return true;
    case nir_texop_tex:
    case nir_texop_txb:

src/compiler/nir/nir.h

@@ -2356,6 +2356,8 @@ typedef enum nir_texop {
    nir_texop_hdr_dim_nv,
    /** Maps to TXQ.TEXTURE_TYPE */
    nir_texop_tex_type_nv,
+   /** Maps to TXQ.SAMPLER_POS */
+   nir_texop_sample_pos_nv,
 } nir_texop;
 
 /** Represents a texture instruction */

src/compiler/nir/nir_print.c

@@ -1865,6 +1865,9 @@ print_tex_instr(nir_tex_instr *instr, print_state *state)
    case nir_texop_tex_type_nv:
       fprintf(fp, "tex_type_nv ");
       break;
+   case nir_texop_sample_pos_nv:
+      fprintf(fp, "sample_pos_nv ");
+      break;
    default:
       unreachable("Invalid texture operation");
       break;

src/compiler/spirv/spirv_to_nir.c

@@ -3508,6 +3508,7 @@ vtn_handle_texture(struct vtn_builder *b, SpvOp opcode,
       break;
    case nir_texop_hdr_dim_nv:
    case nir_texop_tex_type_nv:
+   case nir_texop_sample_pos_nv:
       vtn_fail("unexpected nir_texop_*_nv");
       break;
    }

src/nouveau/compiler/nak/from_nir.rs

@@ -1866,6 +1866,17 @@ impl<'a> ShaderFromNir<'a> {
                 nodep: flags.nodep(),
                 channel_mask,
             });
+        } else if tex.op == nir_texop_sample_pos_nv {
+            let src = self.get_src(&srcs[0].src);
+            assert!(fault.is_none());
+            b.push_op(OpTxq {
+                dsts: dsts,
+                tex: tex_ref,
+                src: src,
+                query: TexQuery::SamplerPos,
+                nodep: flags.nodep(),
+                channel_mask,
+            });
         } else {
             let lod_mode = match flags.lod_mode() {
                 NAK_NIR_LOD_MODE_AUTO => TexLodMode::Auto,