pan/bi: Add support for load_vertex_id

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <mesa/mesa!7472>

src/panfrost/bifrost/bifrost_compile.c

@@ -741,6 +741,20 @@ bi_emit_point_coord(bi_context *ctx, nir_intrinsic_instr *instr)
         bi_emit(ctx, ins);
 }
 
+static void
+bi_emit_vertex_id(bi_context *ctx, nir_intrinsic_instr *instr)
+{
+        bi_instruction mov = {
+                .type = BI_MOV,
+                .dest = pan_dest_index(&instr->dest),
+                .dest_type = nir_type_int32,
+                .src = { BIR_INDEX_REGISTER | 61 },
+                .src_types = { nir_type_int32 },
+        };
+
+        bi_emit(ctx, mov);
+}
+
 static void
 emit_intrinsic(bi_context *ctx, nir_intrinsic_instr *instr)
 {
@@ -832,6 +846,10 @@ emit_intrinsic(bi_context *ctx, nir_intrinsic_instr *instr)
                 bi_emit_point_coord(ctx, instr);
                 break;
 
+        case nir_intrinsic_load_vertex_id:
+                bi_emit_vertex_id(ctx, instr);
+                break;
+
         default:
                 unreachable("Unknown intrinsic");
                 break;