pan/bi: Emit discard (not if)

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4883>
diff --git a/src/panfrost/bifrost/bifrost_compile.c b/src/panfrost/bifrost/bifrost_compile.c
index 2b5b507..b5027e1 100644
--- a/src/panfrost/bifrost/bifrost_compile.c
+++ b/src/panfrost/bifrost/bifrost_compile.c
@@ -352,6 +352,20 @@
 }
 
 static void
+bi_emit_discard(bi_context *ctx, nir_intrinsic_instr *instr)
+{
+        /* Goofy lowering */
+        bi_instruction discard = {
+                .type = BI_DISCARD,
+                .cond = BI_COND_EQ,
+                .src_types = { nir_type_uint32, nir_type_uint32 },
+                .src = { BIR_INDEX_ZERO, BIR_INDEX_ZERO },
+        };
+
+        bi_emit(ctx, discard);
+}
+
+static void
 bi_emit_discard_if(bi_context *ctx, nir_intrinsic_instr *instr)
 {
         nir_src cond = instr->src[0];
@@ -406,6 +420,10 @@
                 bi_emit_ld_frag_coord(ctx, instr);
                 break;
 
+        case nir_intrinsic_discard:
+                bi_emit_discard(ctx, instr);
+                break;
+
         case nir_intrinsic_discard_if:
                 bi_emit_discard_if(ctx, instr);
                 break;