pan/bi: Add support for load_sample_id

Sample ID is preloaded in r61.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7206>
diff --git a/src/panfrost/bifrost/bifrost_compile.c b/src/panfrost/bifrost/bifrost_compile.c
index c8f9762..8ccbe0a 100644
--- a/src/panfrost/bifrost/bifrost_compile.c
+++ b/src/panfrost/bifrost/bifrost_compile.c
@@ -535,6 +535,34 @@
 }
 
 static void
+bi_emit_sample_id(bi_context *ctx, nir_intrinsic_instr *instr)
+{
+        bi_instruction ins = {
+                .type = BI_BITWISE,
+                .op.bitwise = BI_BITWISE_AND,
+                .bitwise.rshift = true,
+                .dest = pan_dest_index(&instr->dest),
+                .dest_type = nir_type_uint32,
+                .src = {
+                        /* r61[16:23] contains the sampleID */
+                        BIR_INDEX_REGISTER | 61,
+                        /* mask */
+                        BIR_INDEX_CONSTANT | 0,
+                        /* shift */
+                        BIR_INDEX_CONSTANT | 32,
+                },
+                .src_types = {
+                        nir_type_uint32,
+                        nir_type_uint32,
+                        nir_type_uint8,
+                },
+                .constant.u64 = 0xffull | (0x10ull << 32ull)
+        };
+
+        bi_emit(ctx, ins);
+}
+
+static void
 emit_intrinsic(bi_context *ctx, nir_intrinsic_instr *instr)
 {
 
@@ -606,6 +634,10 @@
                 bi_emit_blend_const(ctx, instr);
                 break;
 
+	case nir_intrinsic_load_sample_id:
+                bi_emit_sample_id(ctx, instr);
+                break;
+
         default:
                 unreachable("Unknown intrinsic");
                 break;