radeonsi/gfx10: implement NGG culling for 4x wave32 subgroups

Acked-by: Pierre-Eric Pelloux-Prayer <[email protected]>

1 files changed, 666 insertions, 15 deletions

diff --git a/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c b/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c
index a25c89bac56..8092b796b5d 100644
--- a/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c
+++ b/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c
@@ -28,6 +28,7 @@
 
 #include "util/u_memory.h"
 #include "util/u_prim.h"
+#include "ac_llvm_cull.h"
 
 static LLVMValueRef get_wave_id_in_tg(struct si_shader_context *ctx)
 {
@@ -141,14 +142,44 @@ void gfx10_ngg_build_sendmsg_gs_alloc_req(struct si_shader_context *ctx)
 }
 
 void gfx10_ngg_build_export_prim(struct si_shader_context *ctx,
-				 LLVMValueRef user_edgeflags[3])
+				 LLVMValueRef user_edgeflags[3],
+				 LLVMValueRef prim_passthrough)
 {
-	if (gfx10_is_ngg_passthrough(ctx->shader)) {
+	LLVMBuilderRef builder = ctx->ac.builder;
+
+	if (gfx10_is_ngg_passthrough(ctx->shader) ||
+	    ctx->shader->key.opt.ngg_culling) {
 		ac_build_ifcc(&ctx->ac, si_is_gs_thread(ctx), 6001);
 		{
 			struct ac_ngg_prim prim = {};
 
-			prim.passthrough = ac_get_arg(&ctx->ac, ctx->gs_vtx01_offset);
+			if (prim_passthrough)
+				prim.passthrough = prim_passthrough;
+			else
+				prim.passthrough = ac_get_arg(&ctx->ac, ctx->gs_vtx01_offset);
+
+			/* This is only used with NGG culling, which returns the NGG
+			 * passthrough prim export encoding.
+			 */
+			if (ctx->shader->selector->info.writes_edgeflag) {
+				unsigned all_bits_no_edgeflags = ~SI_NGG_PRIM_EDGE_FLAG_BITS;
+				LLVMValueRef edgeflags = LLVMConstInt(ctx->i32, all_bits_no_edgeflags, 0);
+
+				unsigned num_vertices;
+				ngg_get_vertices_per_prim(ctx, &num_vertices);
+
+				for (unsigned i = 0; i < num_vertices; i++) {
+					unsigned shift = 9 + i*10;
+					LLVMValueRef edge;
+
+					edge = LLVMBuildLoad(builder, user_edgeflags[i], "");
+					edge = LLVMBuildZExt(builder, edge, ctx->i32, "");
+					edge = LLVMBuildShl(builder, edge, LLVMConstInt(ctx->i32, shift, 0), "");
+					edgeflags = LLVMBuildOr(builder, edgeflags, edge, "");
+				}
+				prim.passthrough = LLVMBuildAnd(builder, prim.passthrough, edgeflags, "");
+			}
+
 			ac_build_export_prim(&ctx->ac, &prim);
 		}
 		ac_build_endif(&ctx->ac, 6001);
@@ -535,6 +566,51 @@ static void build_streamout(struct si_shader_context *ctx,
 	}
 }
 
+/* LDS layout of ES vertex data for NGG culling. */
+enum {
+	/* Byte 0: Boolean ES thread accepted (unculled) flag, and later the old
+	 *         ES thread ID. After vertex compaction, compacted ES threads
+	 *         store the old thread ID here to copy input VGPRs from uncompacted
+	 *         ES threads.
+	 * Byte 1: New ES thread ID, loaded by GS to prepare the prim export value.
+	 * Byte 2: TES rel patch ID
+	 * Byte 3: Unused
+	 */
+	lds_byte0_accept_flag = 0,
+	lds_byte0_old_thread_id = 0,
+	lds_byte1_new_thread_id,
+	lds_byte2_tes_rel_patch_id,
+	lds_byte3_unused,
+
+	lds_packed_data = 0, /* lds_byteN_... */
+
+	lds_pos_x,
+	lds_pos_y,
+	lds_pos_z,
+	lds_pos_w,
+	lds_pos_x_div_w,
+	lds_pos_y_div_w,
+	/* If VS: */
+	lds_vertex_id,
+	lds_instance_id, /* optional */
+	/* If TES: */
+	lds_tes_u = lds_vertex_id,
+	lds_tes_v = lds_instance_id,
+	lds_tes_patch_id, /* optional */
+};
+
+static LLVMValueRef si_build_gep_i8(struct si_shader_context *ctx,
+				    LLVMValueRef ptr, unsigned byte_index)
+{
+	assert(byte_index < 4);
+	LLVMTypeRef pi8 = LLVMPointerType(ctx->i8, AC_ADDR_SPACE_LDS);
+	LLVMValueRef index = LLVMConstInt(ctx->i32, byte_index, 0);
+
+	return LLVMBuildGEP(ctx->ac.builder,
+			    LLVMBuildPointerCast(ctx->ac.builder, ptr, pi8, ""),
+			    &index, 1, "");
+}
+
 static unsigned ngg_nogs_vertex_size(struct si_shader *shader)
 {
 	unsigned lds_vertex_size = 0;
@@ -555,6 +631,24 @@ static unsigned ngg_nogs_vertex_size(struct si_shader *shader)
 	    shader->key.mono.u.vs_export_prim_id)
 		lds_vertex_size = MAX2(lds_vertex_size, 1);
 
+	if (shader->key.opt.ngg_culling) {
+		if (shader->selector->type == PIPE_SHADER_VERTEX) {
+			STATIC_ASSERT(lds_instance_id + 1 == 9);
+			lds_vertex_size = MAX2(lds_vertex_size, 9);
+		} else {
+			assert(shader->selector->type == PIPE_SHADER_TESS_EVAL);
+
+			if (shader->selector->info.uses_primid ||
+			    shader->key.mono.u.vs_export_prim_id) {
+				STATIC_ASSERT(lds_tes_patch_id + 2 == 11);
+				lds_vertex_size = MAX2(lds_vertex_size, 11);
+			} else {
+				STATIC_ASSERT(lds_tes_v + 1 == 9);
+				lds_vertex_size = MAX2(lds_vertex_size, 9);
+			}
+		}
+	}
+
 	return lds_vertex_size;
 }
 
@@ -573,6 +667,540 @@ static LLVMValueRef ngg_nogs_vertex_ptr(struct si_shader_context *ctx,
 	return LLVMBuildGEP(ctx->ac.builder, tmp, &vtxid, 1, "");
 }
 
+static void load_bitmasks_2x64(struct si_shader_context *ctx,
+			       LLVMValueRef lds_ptr, unsigned dw_offset,
+			       LLVMValueRef mask[2], LLVMValueRef *total_bitcount)
+{
+	LLVMBuilderRef builder = ctx->ac.builder;
+	LLVMValueRef ptr64 = LLVMBuildPointerCast(builder, lds_ptr,
+						  LLVMPointerType(LLVMArrayType(ctx->i64, 2),
+								  AC_ADDR_SPACE_LDS), "");
+	for (unsigned i = 0; i < 2; i++) {
+		LLVMValueRef index = LLVMConstInt(ctx->i32, dw_offset / 2 + i, 0);
+		mask[i] = LLVMBuildLoad(builder, ac_build_gep0(&ctx->ac, ptr64, index), "");
+	}
+
+	/* We get better code if we don't use the 128-bit bitcount. */
+	*total_bitcount = LLVMBuildAdd(builder, ac_build_bit_count(&ctx->ac, mask[0]),
+				       ac_build_bit_count(&ctx->ac, mask[1]), "");
+}
+
+/**
+ * Given a total thread count, update total and per-wave thread counts in input SGPRs
+ * and return the per-wave thread count.
+ *
+ * \param new_num_threads    Total thread count on the input, per-wave thread count on the output.
+ * \param tg_info	     tg_info SGPR value
+ * \param tg_info_num_bits   the bit size of thread count field in tg_info
+ * \param tg_info_shift      the bit offset of the thread count field in tg_info
+ * \param wave_info          merged_wave_info SGPR value
+ * \param wave_info_num_bits the bit size of thread count field in merged_wave_info
+ * \param wave_info_shift    the bit offset of the thread count field in merged_wave_info
+ */
+static void update_thread_counts(struct si_shader_context *ctx,
+				 LLVMValueRef *new_num_threads,
+				 LLVMValueRef *tg_info,
+				 unsigned tg_info_num_bits,
+				 unsigned tg_info_shift,
+				 LLVMValueRef *wave_info,
+				 unsigned wave_info_num_bits,
+				 unsigned wave_info_shift)
+{
+	LLVMBuilderRef builder = ctx->ac.builder;
+
+	/* Update the total thread count. */
+	unsigned tg_info_mask = ~(u_bit_consecutive(0, tg_info_num_bits) << tg_info_shift);
+	*tg_info = LLVMBuildAnd(builder, *tg_info,
+				LLVMConstInt(ctx->i32, tg_info_mask, 0), "");
+	*tg_info = LLVMBuildOr(builder, *tg_info,
+			       LLVMBuildShl(builder, *new_num_threads,
+					    LLVMConstInt(ctx->i32, tg_info_shift, 0), ""), "");
+
+	/* Update the per-wave thread count. */
+	LLVMValueRef prev_threads = LLVMBuildMul(builder, get_wave_id_in_tg(ctx),
+						 LLVMConstInt(ctx->i32, ctx->ac.wave_size, 0), "");
+	*new_num_threads = LLVMBuildSub(builder, *new_num_threads, prev_threads, "");
+	*new_num_threads = ac_build_imax(&ctx->ac, *new_num_threads, ctx->i32_0);
+	*new_num_threads = ac_build_imin(&ctx->ac, *new_num_threads,
+					LLVMConstInt(ctx->i32, ctx->ac.wave_size, 0));
+	unsigned wave_info_mask = ~(u_bit_consecutive(0, wave_info_num_bits) << wave_info_shift);
+	*wave_info = LLVMBuildAnd(builder, *wave_info,
+				  LLVMConstInt(ctx->i32, wave_info_mask, 0), "");
+	*wave_info = LLVMBuildOr(builder, *wave_info,
+				 LLVMBuildShl(builder, *new_num_threads,
+					      LLVMConstInt(ctx->i32, wave_info_shift, 0), ""), "");
+}
+
+/**
+ * Cull primitives for NGG VS or TES, then compact vertices, which happens
+ * before the VS or TES main function. Return values for the main function.
+ * Also return the position, which is passed to the shader as an input,
+ * so that we don't compute it twice.
+ */
+void gfx10_emit_ngg_culling_epilogue_4x_wave32(struct ac_shader_abi *abi,
+					       unsigned max_outputs,
+					       LLVMValueRef *addrs)
+{
+	struct si_shader_context *ctx = si_shader_context_from_abi(abi);
+	struct si_shader *shader = ctx->shader;
+	struct si_shader_selector *sel = shader->selector;
+	struct si_shader_info *info = &sel->info;
+	LLVMBuilderRef builder = ctx->ac.builder;
+
+	assert(shader->key.opt.ngg_culling);
+	assert(shader->key.as_ngg);
+	assert(sel->type == PIPE_SHADER_VERTEX ||
+	       (sel->type == PIPE_SHADER_TESS_EVAL && !shader->key.as_es));
+
+	LLVMValueRef position[4] = {};
+	for (unsigned i = 0; i < info->num_outputs; i++) {
+		switch (info->output_semantic_name[i]) {
+		case TGSI_SEMANTIC_POSITION:
+			for (unsigned j = 0; j < 4; j++) {
+				position[j] = LLVMBuildLoad(ctx->ac.builder,
+							    addrs[4 * i + j], "");
+			}
+			break;
+		}
+	}
+	assert(position[0]);
+
+	/* Store Position.XYZW into LDS. */
+	LLVMValueRef es_vtxptr = ngg_nogs_vertex_ptr(ctx, get_thread_id_in_tg(ctx));
+	for (unsigned chan = 0; chan < 4; chan++) {
+		LLVMBuildStore(builder, ac_to_integer(&ctx->ac, position[chan]),
+				ac_build_gep0(&ctx->ac, es_vtxptr,
+					      LLVMConstInt(ctx->i32, lds_pos_x + chan, 0)));
+	}
+	/* Store Position.XY / W into LDS. */
+	for (unsigned chan = 0; chan < 2; chan++) {
+		LLVMValueRef val = ac_build_fdiv(&ctx->ac, position[chan], position[3]);
+		LLVMBuildStore(builder, ac_to_integer(&ctx->ac, val),
+				ac_build_gep0(&ctx->ac, es_vtxptr,
+					      LLVMConstInt(ctx->i32, lds_pos_x_div_w + chan, 0)));
+	}
+
+	/* Store VertexID and InstanceID. ES threads will have to load them
+	 * from LDS after vertex compaction and use them instead of their own
+	 * system values.
+	 */
+	bool uses_instance_id = false;
+	bool uses_tes_prim_id = false;
+	LLVMValueRef packed_data = ctx->i32_0;
+
+	if (ctx->type == PIPE_SHADER_VERTEX) {
+		uses_instance_id = sel->info.uses_instanceid ||
+				   shader->key.part.vs.prolog.instance_divisor_is_one ||
+				   shader->key.part.vs.prolog.instance_divisor_is_fetched;
+
+		LLVMBuildStore(builder, ctx->abi.vertex_id,
+			       ac_build_gep0(&ctx->ac, es_vtxptr,
+					     LLVMConstInt(ctx->i32, lds_vertex_id, 0)));
+		if (uses_instance_id) {
+			LLVMBuildStore(builder, ctx->abi.instance_id,
+				       ac_build_gep0(&ctx->ac, es_vtxptr,
+						     LLVMConstInt(ctx->i32, lds_instance_id, 0)));
+		}
+	} else {
+		uses_tes_prim_id = sel->info.uses_primid ||
+				   shader->key.mono.u.vs_export_prim_id;
+
+		assert(ctx->type == PIPE_SHADER_TESS_EVAL);
+		LLVMBuildStore(builder, ac_to_integer(&ctx->ac, ac_get_arg(&ctx->ac, ctx->tes_u)),
+			       ac_build_gep0(&ctx->ac, es_vtxptr,
+					     LLVMConstInt(ctx->i32, lds_tes_u, 0)));
+		LLVMBuildStore(builder, ac_to_integer(&ctx->ac, ac_get_arg(&ctx->ac, ctx->tes_v)),
+			       ac_build_gep0(&ctx->ac, es_vtxptr,
+					     LLVMConstInt(ctx->i32, lds_tes_v, 0)));
+		packed_data = LLVMBuildShl(builder, ac_get_arg(&ctx->ac, ctx->tes_rel_patch_id),
+					   LLVMConstInt(ctx->i32, lds_byte2_tes_rel_patch_id * 8, 0), "");
+		if (uses_tes_prim_id) {
+			LLVMBuildStore(builder, ac_get_arg(&ctx->ac, ctx->args.tes_patch_id),
+				       ac_build_gep0(&ctx->ac, es_vtxptr,
+						     LLVMConstInt(ctx->i32, lds_tes_patch_id, 0)));
+		}
+	}
+	/* Initialize the packed data. */
+	LLVMBuildStore(builder, packed_data,
+		       ac_build_gep0(&ctx->ac, es_vtxptr,
+				     LLVMConstInt(ctx->i32, lds_packed_data, 0)));
+	ac_build_endif(&ctx->ac, ctx->merged_wrap_if_label);
+
+	LLVMValueRef tid = ac_get_thread_id(&ctx->ac);
+
+	/* Initialize the last 3 gs_ngg_scratch dwords to 0, because we may have less
+	 * than 4 waves, but we always read all 4 values. This is where the thread
+	 * bitmasks of unculled threads will be stored.
+	 *
+	 * gs_ngg_scratch layout: esmask[0..3]
+	 */
+	ac_build_ifcc(&ctx->ac,
+		      LLVMBuildICmp(builder, LLVMIntULT, get_thread_id_in_tg(ctx),
+				    LLVMConstInt(ctx->i32, 3, 0), ""), 16101);
+	{
+		LLVMValueRef index = LLVMBuildAdd(builder, tid, ctx->i32_1, "");
+		LLVMBuildStore(builder, ctx->i32_0,
+			       ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, index));
+	}
+	ac_build_endif(&ctx->ac, 16101);
+	ac_build_s_barrier(&ctx->ac);
+
+	/* The hardware requires that there are no holes between unculled vertices,
+	 * which means we have to pack ES threads, i.e. reduce the ES thread count
+	 * and move ES input VGPRs to lower threads. The upside is that varyings
+	 * are only fetched and computed for unculled vertices.
+	 *
+	 * Vertex compaction in GS threads:
+	 *
+	 * Part 1: Compute the surviving vertex mask in GS threads:
+	 * - Compute 4 32-bit surviving vertex masks in LDS. (max 4 waves)
+	 *   - In GS, notify ES threads whether the vertex survived.
+	 *   - Barrier
+	 *   - ES threads will create the mask and store it in LDS.
+	 * - Barrier
+	 * - Each GS thread loads the vertex masks from LDS.
+	 *
+	 * Part 2: Compact ES threads in GS threads:
+	 * - Compute the prefix sum for all 3 vertices from the masks. These are the new
+	 *   thread IDs for each vertex within the primitive.
+	 * - Write the value of the old thread ID into the LDS address of the new thread ID.
+	 *   The ES thread will load the old thread ID and use it to load the position, VertexID,
+	 *   and InstanceID.
+	 * - Update vertex indices and null flag in the GS input VGPRs.
+	 * - Barrier
+	 *
+	 * Part 3: Update inputs GPRs
+	 * - For all waves, update per-wave thread counts in input SGPRs.
+	 * - In ES threads, update the ES input VGPRs (VertexID, InstanceID, TES inputs).
+	 */
+
+	LLVMValueRef vtxindex[] = {
+		si_unpack_param(ctx, ctx->gs_vtx01_offset, 0, 16),
+		si_unpack_param(ctx, ctx->gs_vtx01_offset, 16, 16),
+		si_unpack_param(ctx, ctx->gs_vtx23_offset, 0, 16),
+	};
+	LLVMValueRef gs_vtxptr[] = {
+		ngg_nogs_vertex_ptr(ctx, vtxindex[0]),
+		ngg_nogs_vertex_ptr(ctx, vtxindex[1]),
+		ngg_nogs_vertex_ptr(ctx, vtxindex[2]),
+	};
+	es_vtxptr = ngg_nogs_vertex_ptr(ctx, get_thread_id_in_tg(ctx));
+
+	LLVMValueRef gs_accepted = ac_build_alloca(&ctx->ac, ctx->i32, "");
+
+	/* Do culling in GS threads. */
+	ac_build_ifcc(&ctx->ac, si_is_gs_thread(ctx), 16002);
+	{
+		/* Load positions. */
+		LLVMValueRef pos[3][4] = {};
+		for (unsigned vtx = 0; vtx < 3; vtx++) {
+			for (unsigned chan = 0; chan < 4; chan++) {
+				unsigned index;
+				if (chan == 0 || chan == 1)
+					index = lds_pos_x_div_w + chan;
+				else if (chan == 3)
+					index = lds_pos_w;
+				else
+					continue;
+
+				LLVMValueRef addr = ac_build_gep0(&ctx->ac, gs_vtxptr[vtx],
+								  LLVMConstInt(ctx->i32, index, 0));
+				pos[vtx][chan] = LLVMBuildLoad(builder, addr, "");
+				pos[vtx][chan] = ac_to_float(&ctx->ac, pos[vtx][chan]);
+			}
+		}
+
+		/* Load the viewport state for small prim culling. */
+		LLVMValueRef vp = ac_build_load_invariant(&ctx->ac,
+							  ac_get_arg(&ctx->ac, ctx->small_prim_cull_info),
+							  ctx->i32_0);
+		vp = LLVMBuildBitCast(builder, vp, ctx->v4f32, "");
+		LLVMValueRef vp_scale[2], vp_translate[2];
+		vp_scale[0] = ac_llvm_extract_elem(&ctx->ac, vp, 0);
+		vp_scale[1] = ac_llvm_extract_elem(&ctx->ac, vp, 1);
+		vp_translate[0] = ac_llvm_extract_elem(&ctx->ac, vp, 2);
+		vp_translate[1] = ac_llvm_extract_elem(&ctx->ac, vp, 3);
+
+		/* Get the small prim filter precision. */
+		LLVMValueRef small_prim_precision = si_unpack_param(ctx, ctx->vs_state_bits, 7, 4);
+		small_prim_precision = LLVMBuildOr(builder, small_prim_precision,
+						   LLVMConstInt(ctx->i32, 0x70, 0), "");
+		small_prim_precision = LLVMBuildShl(builder, small_prim_precision,
+						    LLVMConstInt(ctx->i32, 23, 0), "");
+		small_prim_precision = LLVMBuildBitCast(builder, small_prim_precision, ctx->f32, "");
+
+		/* Execute culling code. */
+		struct ac_cull_options options = {};
+		options.cull_front = shader->key.opt.ngg_culling & SI_NGG_CULL_FRONT_FACE;
+		options.cull_back = shader->key.opt.ngg_culling & SI_NGG_CULL_BACK_FACE;
+		options.cull_view_xy = shader->key.opt.ngg_culling & SI_NGG_CULL_VIEW_SMALLPRIMS;
+		options.cull_small_prims = options.cull_view_xy;
+		options.cull_zero_area = options.cull_front || options.cull_back;
+		options.cull_w = true;
+
+		/* Tell ES threads whether their vertex survived. */
+		ac_build_ifcc(&ctx->ac, ac_cull_triangle(&ctx->ac, pos, ctx->i1true,
+							 vp_scale, vp_translate,
+							 small_prim_precision, &options), 16003);
+		{
+			LLVMBuildStore(builder, ctx->ac.i32_1, gs_accepted);
+			for (unsigned vtx = 0; vtx < 3; vtx++) {
+				LLVMBuildStore(builder, ctx->ac.i8_1,
+					       si_build_gep_i8(ctx, gs_vtxptr[vtx], lds_byte0_accept_flag));
+			}
+		}
+		ac_build_endif(&ctx->ac, 16003);
+	}
+	ac_build_endif(&ctx->ac, 16002);
+	ac_build_s_barrier(&ctx->ac);
+
+	gs_accepted = LLVMBuildLoad(builder, gs_accepted, "");
+
+	LLVMValueRef es_accepted = ac_build_alloca(&ctx->ac, ctx->i1, "");
+
+	/* Convert the per-vertex flag to a thread bitmask in ES threads and store it in LDS. */
+	ac_build_ifcc(&ctx->ac, si_is_es_thread(ctx), 16007);
+	{
+		LLVMValueRef es_accepted_flag =
+			LLVMBuildLoad(builder,
+				      si_build_gep_i8(ctx, es_vtxptr, lds_byte0_accept_flag), "");
+
+		LLVMValueRef es_accepted_bool = LLVMBuildICmp(builder, LLVMIntNE,
+							      es_accepted_flag, ctx->ac.i8_0, "");
+		LLVMValueRef es_mask = ac_get_i1_sgpr_mask(&ctx->ac, es_accepted_bool);
+
+		LLVMBuildStore(builder, es_accepted_bool, es_accepted);
+
+		ac_build_ifcc(&ctx->ac, LLVMBuildICmp(builder, LLVMIntEQ,
+						      tid, ctx->i32_0, ""), 16008);
+		{
+			LLVMBuildStore(builder, es_mask,
+				       ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch,
+						     get_wave_id_in_tg(ctx)));
+		}
+		ac_build_endif(&ctx->ac, 16008);
+	}
+	ac_build_endif(&ctx->ac, 16007);
+	ac_build_s_barrier(&ctx->ac);
+
+	/* Load the vertex masks and compute the new ES thread count. */
+	LLVMValueRef es_mask[2], new_num_es_threads, kill_wave;
+	load_bitmasks_2x64(ctx, ctx->gs_ngg_scratch, 0, es_mask, &new_num_es_threads);
+	new_num_es_threads = ac_build_readlane_no_opt_barrier(&ctx->ac, new_num_es_threads, NULL);
+
+	/* ES threads compute their prefix sum, which is the new ES thread ID.
+	 * Then they write the value of the old thread ID into the LDS address
+	 * of the new thread ID. It will be used it to load input VGPRs from
+	 * the old thread's LDS location.
+	 */
+	ac_build_ifcc(&ctx->ac, LLVMBuildLoad(builder, es_accepted, ""), 16009);
+	{
+		LLVMValueRef old_id = get_thread_id_in_tg(ctx);
+		LLVMValueRef new_id = ac_prefix_bitcount_2x64(&ctx->ac, es_mask, old_id);
+
+		LLVMBuildStore(builder, LLVMBuildTrunc(builder, old_id, ctx->i8, ""),
+			       si_build_gep_i8(ctx, ngg_nogs_vertex_ptr(ctx, new_id),
+					       lds_byte0_old_thread_id));
+		LLVMBuildStore(builder, LLVMBuildTrunc(builder, new_id, ctx->i8, ""),
+			       si_build_gep_i8(ctx, es_vtxptr, lds_byte1_new_thread_id));
+	}
+	ac_build_endif(&ctx->ac, 16009);
+
+	/* Kill waves that have inactive threads. */
+	kill_wave = LLVMBuildICmp(builder, LLVMIntULE,
+				  ac_build_imax(&ctx->ac, new_num_es_threads, ngg_get_prim_cnt(ctx)),
+				  LLVMBuildMul(builder, get_wave_id_in_tg(ctx),
+					       LLVMConstInt(ctx->i32, ctx->ac.wave_size, 0), ""), "");
+	ac_build_ifcc(&ctx->ac, kill_wave, 19202);
+	{
+		/* If we are killing wave 0, send that there are no primitives
+		 * in this threadgroup.
+		 */
+		ac_build_sendmsg_gs_alloc_req(&ctx->ac, get_wave_id_in_tg(ctx),
+					      ctx->i32_0, ctx->i32_0);
+		ac_build_s_endpgm(&ctx->ac);
+	}
+	ac_build_endif(&ctx->ac, 19202);
+	ac_build_s_barrier(&ctx->ac);
+
+	/* Send the final vertex and primitive counts. */
+	ac_build_sendmsg_gs_alloc_req(&ctx->ac, get_wave_id_in_tg(ctx),
+				      new_num_es_threads, ngg_get_prim_cnt(ctx));
+
+	/* Update thread counts in SGPRs. */
+	LLVMValueRef new_gs_tg_info = ac_get_arg(&ctx->ac, ctx->gs_tg_info);
+	LLVMValueRef new_merged_wave_info = ac_get_arg(&ctx->ac, ctx->merged_wave_info);
+
+	/* This also converts the thread count from the total count to the per-wave count. */
+	update_thread_counts(ctx, &new_num_es_threads, &new_gs_tg_info, 9, 12,
+			     &new_merged_wave_info, 8, 0);
+
+	/* Update vertex indices in VGPR0 (same format as NGG passthrough). */
+	LLVMValueRef new_vgpr0 = ac_build_alloca_undef(&ctx->ac, ctx->i32, "");
+
+	/* Set the null flag at the beginning (culled), and then
+	 * overwrite it for accepted primitives.
+	 */
+	LLVMBuildStore(builder, LLVMConstInt(ctx->i32, 1u << 31, 0), new_vgpr0);
+
+	/* Get vertex indices after vertex compaction. */
+	ac_build_ifcc(&ctx->ac, LLVMBuildTrunc(builder, gs_accepted, ctx->i1, ""), 16011);
+	{
+		struct ac_ngg_prim prim = {};
+		prim.num_vertices = 3;
+		prim.isnull = ctx->i1false;
+
+		for (unsigned vtx = 0; vtx < 3; vtx++) {
+			prim.index[vtx] =
+				LLVMBuildLoad(builder,
+					      si_build_gep_i8(ctx, gs_vtxptr[vtx],
+							      lds_byte1_new_thread_id), "");
+			prim.index[vtx] = LLVMBuildZExt(builder, prim.index[vtx], ctx->i32, "");
+			prim.edgeflag[vtx] = ngg_get_initial_edgeflag(ctx, vtx);
+		}
+
+		/* Set the new GS input VGPR. */
+		LLVMBuildStore(builder, ac_pack_prim_export(&ctx->ac, &prim), new_vgpr0);
+	}
+	ac_build_endif(&ctx->ac, 16011);
+
+	if (gfx10_ngg_export_prim_early(shader))
+		gfx10_ngg_build_export_prim(ctx, NULL, LLVMBuildLoad(builder, new_vgpr0, ""));
+
+	/* Set the new ES input VGPRs. */
+	LLVMValueRef es_data[4];
+	LLVMValueRef old_thread_id = ac_build_alloca_undef(&ctx->ac, ctx->i32, "");
+
+	for (unsigned i = 0; i < 4; i++)
+		es_data[i] = ac_build_alloca_undef(&ctx->ac, ctx->i32, "");
+
+	ac_build_ifcc(&ctx->ac, LLVMBuildICmp(ctx->ac.builder, LLVMIntULT, tid,
+					      new_num_es_threads, ""), 16012);
+	{
+		LLVMValueRef old_id, old_es_vtxptr, tmp;
+
+		/* Load ES input VGPRs from the ES thread before compaction. */
+		old_id = LLVMBuildLoad(builder,
+				       si_build_gep_i8(ctx, es_vtxptr, lds_byte0_old_thread_id), "");
+		old_id = LLVMBuildZExt(builder, old_id, ctx->i32, "");
+
+		LLVMBuildStore(builder, old_id, old_thread_id);
+		old_es_vtxptr = ngg_nogs_vertex_ptr(ctx, old_id);
+
+		for (unsigned i = 0; i < 2; i++) {
+			tmp = LLVMBuildLoad(builder,
+					    ac_build_gep0(&ctx->ac, old_es_vtxptr,
+							  LLVMConstInt(ctx->i32, lds_vertex_id + i, 0)), "");
+			LLVMBuildStore(builder, tmp, es_data[i]);
+		}
+
+		if (ctx->type == PIPE_SHADER_TESS_EVAL) {
+			tmp = LLVMBuildLoad(builder,
+					    si_build_gep_i8(ctx, old_es_vtxptr,
+							    lds_byte2_tes_rel_patch_id), "");
+			tmp = LLVMBuildZExt(builder, tmp, ctx->i32, "");
+			LLVMBuildStore(builder, tmp, es_data[2]);
+
+			if (uses_tes_prim_id) {
+				tmp = LLVMBuildLoad(builder,
+						    ac_build_gep0(&ctx->ac, old_es_vtxptr,
+								  LLVMConstInt(ctx->i32, lds_tes_patch_id, 0)), "");
+				LLVMBuildStore(builder, tmp, es_data[3]);
+			}
+		}
+	}
+	ac_build_endif(&ctx->ac, 16012);
+
+	/* Return values for the main function. */
+	LLVMValueRef ret = ctx->return_value;
+	LLVMValueRef val;
+
+	ret = LLVMBuildInsertValue(ctx->ac.builder, ret, new_gs_tg_info, 2, "");
+	ret = LLVMBuildInsertValue(ctx->ac.builder, ret, new_merged_wave_info, 3, "");
+	if (ctx->type == PIPE_SHADER_TESS_EVAL)
+		ret = si_insert_input_ret(ctx, ret, ctx->tcs_offchip_offset, 4);
+
+	ret = si_insert_input_ptr(ctx, ret, ctx->rw_buffers,
+				  8 + SI_SGPR_RW_BUFFERS);
+	ret = si_insert_input_ptr(ctx, ret,
+				  ctx->bindless_samplers_and_images,
+				  8 + SI_SGPR_BINDLESS_SAMPLERS_AND_IMAGES);
+	ret = si_insert_input_ptr(ctx, ret,
+				  ctx->const_and_shader_buffers,
+				  8 + SI_SGPR_CONST_AND_SHADER_BUFFERS);
+	ret = si_insert_input_ptr(ctx, ret,
+				  ctx->samplers_and_images,
+				  8 + SI_SGPR_SAMPLERS_AND_IMAGES);
+	ret = si_insert_input_ptr(ctx, ret, ctx->vs_state_bits,
+				  8 + SI_SGPR_VS_STATE_BITS);
+
+	if (ctx->type == PIPE_SHADER_VERTEX) {
+		ret = si_insert_input_ptr(ctx, ret, ctx->args.base_vertex,
+					  8 + SI_SGPR_BASE_VERTEX);
+		ret = si_insert_input_ptr(ctx, ret, ctx->args.start_instance,
+					  8 + SI_SGPR_START_INSTANCE);
+		ret = si_insert_input_ptr(ctx, ret, ctx->args.draw_id,
+					  8 + SI_SGPR_DRAWID);
+		ret = si_insert_input_ptr(ctx, ret, ctx->vertex_buffers,
+					  8 + SI_VS_NUM_USER_SGPR);
+	} else {
+		assert(ctx->type == PIPE_SHADER_TESS_EVAL);
+		ret = si_insert_input_ptr(ctx, ret, ctx->tcs_offchip_layout,
+					  8 + SI_SGPR_TES_OFFCHIP_LAYOUT);
+		ret = si_insert_input_ptr(ctx, ret, ctx->tes_offchip_addr,
+					  8 + SI_SGPR_TES_OFFCHIP_ADDR);
+	}
+
+	unsigned vgpr;
+	if (ctx->type == PIPE_SHADER_VERTEX)
+		vgpr = 8 + GFX9_VSGS_NUM_USER_SGPR + 1;
+	else
+		vgpr = 8 + GFX9_TESGS_NUM_USER_SGPR;
+
+	val = LLVMBuildLoad(builder, new_vgpr0, "");
+	ret = LLVMBuildInsertValue(builder, ret, ac_to_float(&ctx->ac, val),
+				   vgpr++, "");
+	vgpr++; /* gs_vtx23_offset */
+
+	ret = si_insert_input_ret_float(ctx, ret, ctx->args.gs_prim_id, vgpr++);
+	ret = si_insert_input_ret_float(ctx, ret, ctx->args.gs_invocation_id, vgpr++);
+	vgpr++; /* gs_vtx45_offset */
+
+	if (ctx->type == PIPE_SHADER_VERTEX) {
+		val = LLVMBuildLoad(builder, es_data[0], "");
+		ret = LLVMBuildInsertValue(builder, ret, ac_to_float(&ctx->ac, val),
+					   vgpr++, ""); /* VGPR5 - VertexID */
+		vgpr += 2;
+		if (uses_instance_id) {
+			val = LLVMBuildLoad(builder, es_data[1], "");
+			ret = LLVMBuildInsertValue(builder, ret, ac_to_float(&ctx->ac, val),
+						   vgpr++, ""); /* VGPR8 - InstanceID */
+		} else {
+			vgpr++;
+		}
+	} else {
+		assert(ctx->type == PIPE_SHADER_TESS_EVAL);
+		unsigned num_vgprs = uses_tes_prim_id ? 4 : 3;
+		for (unsigned i = 0; i < num_vgprs; i++) {
+			val = LLVMBuildLoad(builder, es_data[i], "");
+			ret = LLVMBuildInsertValue(builder, ret, ac_to_float(&ctx->ac, val),
+						   vgpr++, "");
+		}
+		if (num_vgprs == 3)
+			vgpr++;
+	}
+	/* Return the old thread ID. */
+	val = LLVMBuildLoad(builder, old_thread_id, "");
+	ret = LLVMBuildInsertValue(builder, ret, ac_to_float(&ctx->ac, val), vgpr++, "");
+
+	/* These two also use LDS. */
+	if (sel->info.writes_edgeflag ||
+	    (ctx->type == PIPE_SHADER_VERTEX && shader->key.mono.u.vs_export_prim_id))
+		ac_build_s_barrier(&ctx->ac);
+
+	ctx->return_value = ret;
+}
+
 /**
  * Emit the epilogue of an API VS or TES shader compiled as ESGS shader.
  */
@@ -630,7 +1258,8 @@ void gfx10_emit_ngg_epilogue(struct ac_shader_abi *abi,
 	}
 
 	bool unterminated_es_if_block =
-		gfx10_is_ngg_passthrough(ctx->shader) &&
+		!sel->so.num_outputs &&
+		!sel->info.writes_edgeflag &&
 		!ctx->screen->use_ngg_streamout && /* no query buffer */
 		(ctx->type != PIPE_SHADER_VERTEX ||
 		 !ctx->shader->key.mono.u.vs_export_prim_id);
@@ -640,11 +1269,17 @@ void gfx10_emit_ngg_epilogue(struct ac_shader_abi *abi,
 
 	LLVMValueRef is_gs_thread = si_is_gs_thread(ctx);
 	LLVMValueRef is_es_thread = si_is_es_thread(ctx);
-	LLVMValueRef vtxindex[] = {
-		si_unpack_param(ctx, ctx->gs_vtx01_offset, 0, 16),
-		si_unpack_param(ctx, ctx->gs_vtx01_offset, 16, 16),
-		si_unpack_param(ctx, ctx->gs_vtx23_offset, 0, 16),
-	};
+	LLVMValueRef vtxindex[3];
+
+	if (ctx->shader->key.opt.ngg_culling) {
+		vtxindex[0] = si_unpack_param(ctx, ctx->gs_vtx01_offset, 0, 9);
+		vtxindex[1] = si_unpack_param(ctx, ctx->gs_vtx01_offset, 10, 9);
+		vtxindex[2] = si_unpack_param(ctx, ctx->gs_vtx01_offset, 20, 9);
+	} else {
+		vtxindex[0] = si_unpack_param(ctx, ctx->gs_vtx01_offset, 0, 16);
+		vtxindex[1] = si_unpack_param(ctx, ctx->gs_vtx01_offset, 16, 16);
+		vtxindex[2] = si_unpack_param(ctx, ctx->gs_vtx23_offset, 0, 16);
+	}
 
 	/* Determine the number of vertices per primitive. */
 	unsigned num_vertices;
@@ -758,7 +1393,7 @@ void gfx10_emit_ngg_epilogue(struct ac_shader_abi *abi,
 	/* Build the primitive export. */
 	if (!gfx10_ngg_export_prim_early(ctx->shader)) {
 		assert(!unterminated_es_if_block);
-		gfx10_ngg_build_export_prim(ctx, user_edgeflags);
+		gfx10_ngg_build_export_prim(ctx, user_edgeflags, NULL);
 	}
 
 	/* Export per-vertex data (positions and parameters). */
@@ -769,11 +1404,27 @@ void gfx10_emit_ngg_epilogue(struct ac_shader_abi *abi,
 
 		/* Unconditionally (re-)load the values for proper SSA form. */
 		for (i = 0; i < info->num_outputs; i++) {
-			for (unsigned j = 0; j < 4; j++) {
-				outputs[i].values[j] =
-					LLVMBuildLoad(builder,
-						addrs[4 * i + j],
-						"");
+			/* If the NGG cull shader part computed the position, don't
+			 * use the position from the current shader part. Instead,
+			 * load it from LDS.
+			 */
+			if (info->output_semantic_name[i] == TGSI_SEMANTIC_POSITION &&
+			    ctx->shader->key.opt.ngg_culling) {
+				vertex_ptr = ngg_nogs_vertex_ptr(ctx,
+						ac_get_arg(&ctx->ac, ctx->ngg_old_thread_id));
+
+				for (unsigned j = 0; j < 4; j++) {
+					tmp = LLVMConstInt(ctx->i32, lds_pos_x + j, 0);
+					tmp = ac_build_gep0(&ctx->ac, vertex_ptr, tmp);
+					tmp = LLVMBuildLoad(builder, tmp, "");
+					outputs[i].values[j] = ac_to_float(&ctx->ac, tmp);
+				}
+			} else {
+				for (unsigned j = 0; j < 4; j++) {
+					outputs[i].values[j] =
+						LLVMBuildLoad(builder,
+							      addrs[4 * i + j], "");
+				}
 			}
 		}