[mesa.git] / src / gallium / drivers / radeonsi / gfx10_shader_ngg.c

/*
 * Copyright 2017 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include "si_pipe.h"
#include "si_shader_internal.h"

#include "sid.h"

#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)
{
        return si_unpack_param(ctx, ctx->merged_wave_info, 24, 4);
}

static LLVMValueRef get_tgsize(struct si_shader_context *ctx)
{
        return si_unpack_param(ctx, ctx->merged_wave_info, 28, 4);
}

static LLVMValueRef get_thread_id_in_tg(struct si_shader_context *ctx)
{
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef tmp;
        tmp = LLVMBuildMul(builder, get_wave_id_in_tg(ctx),
                           LLVMConstInt(ctx->ac.i32, ctx->ac.wave_size, false), "");
        return LLVMBuildAdd(builder, tmp, ac_get_thread_id(&ctx->ac), "");
}

static LLVMValueRef ngg_get_vtx_cnt(struct si_shader_context *ctx)
{
        return si_unpack_param(ctx, ctx->gs_tg_info, 12, 9);
}

static LLVMValueRef ngg_get_prim_cnt(struct si_shader_context *ctx)
{
        return si_unpack_param(ctx, ctx->gs_tg_info, 22, 9);
}

static LLVMValueRef ngg_get_ordered_id(struct si_shader_context *ctx)
{
        return si_unpack_param(ctx, ctx->gs_tg_info, 0, 12);
}

static LLVMValueRef ngg_get_query_buf(struct si_shader_context *ctx)
{
        LLVMValueRef buf_ptr = ac_get_arg(&ctx->ac, ctx->rw_buffers);

        return ac_build_load_to_sgpr(&ctx->ac, buf_ptr,
                                     LLVMConstInt(ctx->i32, GFX10_GS_QUERY_BUF, false));
}

static LLVMValueRef ngg_get_initial_edgeflag(struct si_shader_context *ctx, unsigned index)
{
        if (ctx->type == PIPE_SHADER_VERTEX) {
                LLVMValueRef tmp;
                tmp = LLVMBuildLShr(ctx->ac.builder,
                                    ac_get_arg(&ctx->ac, ctx->args.gs_invocation_id),
                                    LLVMConstInt(ctx->ac.i32, 8 + index, false), "");
                return LLVMBuildTrunc(ctx->ac.builder, tmp, ctx->ac.i1, "");
        }
        return ctx->i1false;
}

/**
 * Return the number of vertices as a constant in \p num_vertices,
 * and return a more precise value as LLVMValueRef from the function.
 */
static LLVMValueRef ngg_get_vertices_per_prim(struct si_shader_context *ctx,
                                              unsigned *num_vertices)
{
        const struct si_shader_info *info = &ctx->shader->selector->info;

        if (ctx->type == PIPE_SHADER_VERTEX) {
                if (info->properties[TGSI_PROPERTY_VS_BLIT_SGPRS_AMD]) {
                        /* Blits always use axis-aligned rectangles with 3 vertices. */
                        *num_vertices = 3;
                        return LLVMConstInt(ctx->i32, 3, 0);
                } else {
                        /* We always build up all three indices for the prim export
                         * independent of the primitive type. The additional garbage
                         * data shouldn't hurt. This number doesn't matter with
                         * NGG passthrough.
                         */
                        *num_vertices = 3;

                        /* Extract OUTPRIM field. */
                        LLVMValueRef num = si_unpack_param(ctx, ctx->vs_state_bits, 2, 2);
                        return LLVMBuildAdd(ctx->ac.builder, num, ctx->i32_1, "");
                }
        } else {
                assert(ctx->type == PIPE_SHADER_TESS_EVAL);

                if (info->properties[TGSI_PROPERTY_TES_POINT_MODE])
                        *num_vertices = 1;
                else if (info->properties[TGSI_PROPERTY_TES_PRIM_MODE] == PIPE_PRIM_LINES)
                        *num_vertices = 2;
                else
                        *num_vertices = 3;

                return LLVMConstInt(ctx->i32, *num_vertices, false);
        }
}

bool gfx10_ngg_export_prim_early(struct si_shader *shader)
{
        struct si_shader_selector *sel = shader->selector;

        assert(shader->key.as_ngg && !shader->key.as_es);

        return sel->type != PIPE_SHADER_GEOMETRY &&
               !sel->info.writes_edgeflag;
}

void gfx10_ngg_build_sendmsg_gs_alloc_req(struct si_shader_context *ctx)
{
        ac_build_sendmsg_gs_alloc_req(&ctx->ac, get_wave_id_in_tg(ctx),
                                      ngg_get_vtx_cnt(ctx),
                                      ngg_get_prim_cnt(ctx));
}

void gfx10_ngg_build_export_prim(struct si_shader_context *ctx,
                                 LLVMValueRef user_edgeflags[3],
                                 LLVMValueRef prim_passthrough)
{
        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 = {};

                        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);
                return;
        }

        ac_build_ifcc(&ctx->ac, si_is_gs_thread(ctx), 6001);
        {
                struct ac_ngg_prim prim = {};

                ngg_get_vertices_per_prim(ctx, &prim.num_vertices);

                prim.isnull = ctx->ac.i1false;
                prim.index[0] = si_unpack_param(ctx, ctx->gs_vtx01_offset, 0, 16);
                prim.index[1] = si_unpack_param(ctx, ctx->gs_vtx01_offset, 16, 16);
                prim.index[2] = si_unpack_param(ctx, ctx->gs_vtx23_offset, 0, 16);

                for (unsigned i = 0; i < prim.num_vertices; ++i) {
                        prim.edgeflag[i] = ngg_get_initial_edgeflag(ctx, i);

                        if (ctx->shader->selector->info.writes_edgeflag) {
                                LLVMValueRef edge;

                                edge = LLVMBuildLoad(ctx->ac.builder, user_edgeflags[i], "");
                                edge = LLVMBuildAnd(ctx->ac.builder, prim.edgeflag[i], edge, "");
                                prim.edgeflag[i] = edge;
                        }
                }

                ac_build_export_prim(&ctx->ac, &prim);
        }
        ac_build_endif(&ctx->ac, 6001);
}

static void build_streamout_vertex(struct si_shader_context *ctx,
                                   LLVMValueRef *so_buffer, LLVMValueRef *wg_offset_dw,
                                   unsigned stream, LLVMValueRef offset_vtx,
                                   LLVMValueRef vertexptr)
{
        struct si_shader_info *info = &ctx->shader->selector->info;
        struct pipe_stream_output_info *so = &ctx->shader->selector->so;
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef offset[4] = {};
        LLVMValueRef tmp;

        for (unsigned buffer = 0; buffer < 4; ++buffer) {
                if (!wg_offset_dw[buffer])
                        continue;

                tmp = LLVMBuildMul(builder, offset_vtx,
                                   LLVMConstInt(ctx->i32, so->stride[buffer], false), "");
                tmp = LLVMBuildAdd(builder, wg_offset_dw[buffer], tmp, "");
                offset[buffer] = LLVMBuildShl(builder, tmp, LLVMConstInt(ctx->i32, 2, false), "");
        }

        for (unsigned i = 0; i < so->num_outputs; ++i) {
                if (so->output[i].stream != stream)
                        continue;

                unsigned reg = so->output[i].register_index;
                struct si_shader_output_values out;
                out.semantic_name = info->output_semantic_name[reg];
                out.semantic_index = info->output_semantic_index[reg];

                for (unsigned comp = 0; comp < 4; comp++) {
                        tmp = ac_build_gep0(&ctx->ac, vertexptr,
                                            LLVMConstInt(ctx->i32, 4 * reg + comp, false));
                        out.values[comp] = LLVMBuildLoad(builder, tmp, "");
                        out.vertex_stream[comp] =
                                (info->output_streams[reg] >> (2 * comp)) & 3;
                }

                si_emit_streamout_output(ctx, so_buffer, offset, &so->output[i], &out);
        }
}

struct ngg_streamout {
        LLVMValueRef num_vertices;

        /* per-thread data */
        LLVMValueRef prim_enable[4]; /* i1 per stream */
        LLVMValueRef vertices[3]; /* [N x i32] addrspace(LDS)* */

        /* Output */
        LLVMValueRef emit[4]; /* per-stream emitted primitives (only valid for used streams) */
};

/**
 * Build streamout logic.
 *
 * Implies a barrier.
 *
 * Writes number of emitted primitives to gs_ngg_scratch[4:8].
 *
 * Clobbers gs_ngg_scratch[8:].
 */
static void build_streamout(struct si_shader_context *ctx,
                            struct ngg_streamout *nggso)
{
        struct si_shader_info *info = &ctx->shader->selector->info;
        struct pipe_stream_output_info *so = &ctx->shader->selector->so;
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef buf_ptr = ac_get_arg(&ctx->ac, ctx->rw_buffers);
        LLVMValueRef tid = get_thread_id_in_tg(ctx);
        LLVMValueRef tmp, tmp2;
        LLVMValueRef i32_2 = LLVMConstInt(ctx->i32, 2, false);
        LLVMValueRef i32_4 = LLVMConstInt(ctx->i32, 4, false);
        LLVMValueRef i32_8 = LLVMConstInt(ctx->i32, 8, false);
        LLVMValueRef so_buffer[4] = {};
        unsigned max_num_vertices = 1 + (nggso->vertices[1] ? 1 : 0) +
                                        (nggso->vertices[2] ? 1 : 0);
        LLVMValueRef prim_stride_dw[4] = {};
        LLVMValueRef prim_stride_dw_vgpr = LLVMGetUndef(ctx->i32);
        int stream_for_buffer[4] = { -1, -1, -1, -1 };
        unsigned bufmask_for_stream[4] = {};
        bool isgs = ctx->type == PIPE_SHADER_GEOMETRY;
        unsigned scratch_emit_base = isgs ? 4 : 0;
        LLVMValueRef scratch_emit_basev = isgs ? i32_4 : ctx->i32_0;
        unsigned scratch_offset_base = isgs ? 8 : 4;
        LLVMValueRef scratch_offset_basev = isgs ? i32_8 : i32_4;

        ac_llvm_add_target_dep_function_attr(ctx->main_fn, "amdgpu-gds-size", 256);

        /* Determine the mapping of streamout buffers to vertex streams. */
        for (unsigned i = 0; i < so->num_outputs; ++i) {
                unsigned buf = so->output[i].output_buffer;
                unsigned stream = so->output[i].stream;
                assert(stream_for_buffer[buf] < 0 || stream_for_buffer[buf] == stream);
                stream_for_buffer[buf] = stream;
                bufmask_for_stream[stream] |= 1 << buf;
        }

        for (unsigned buffer = 0; buffer < 4; ++buffer) {
                if (stream_for_buffer[buffer] == -1)
                        continue;

                assert(so->stride[buffer]);

                tmp = LLVMConstInt(ctx->i32, so->stride[buffer], false);
                prim_stride_dw[buffer] = LLVMBuildMul(builder, tmp, nggso->num_vertices, "");
                prim_stride_dw_vgpr = ac_build_writelane(
                        &ctx->ac, prim_stride_dw_vgpr, prim_stride_dw[buffer],
                        LLVMConstInt(ctx->i32, buffer, false));

                so_buffer[buffer] = ac_build_load_to_sgpr(
                        &ctx->ac, buf_ptr,
                        LLVMConstInt(ctx->i32, SI_VS_STREAMOUT_BUF0 + buffer, false));
        }

        tmp = LLVMBuildICmp(builder, LLVMIntEQ, get_wave_id_in_tg(ctx), ctx->i32_0, "");
        ac_build_ifcc(&ctx->ac, tmp, 5200);
        {
                LLVMTypeRef gdsptr = LLVMPointerType(ctx->i32, AC_ADDR_SPACE_GDS);
                LLVMValueRef gdsbase = LLVMBuildIntToPtr(builder, ctx->i32_0, gdsptr, "");

                /* Advance the streamout offsets in GDS. */
                LLVMValueRef offsets_vgpr = ac_build_alloca_undef(&ctx->ac, ctx->i32, "");
                LLVMValueRef generated_by_stream_vgpr = ac_build_alloca_undef(&ctx->ac, ctx->i32, "");

                tmp = LLVMBuildICmp(builder, LLVMIntULT, ac_get_thread_id(&ctx->ac), i32_4, "");
                ac_build_ifcc(&ctx->ac, tmp, 5210);
                {
                        if (isgs) {
                                tmp = ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, tid);
                                tmp = LLVMBuildLoad(builder, tmp, "");
                        } else {
                                tmp = ac_build_writelane(&ctx->ac, ctx->i32_0,
                                                ngg_get_prim_cnt(ctx), ctx->i32_0);
                        }
                        LLVMBuildStore(builder, tmp, generated_by_stream_vgpr);

                        unsigned swizzle[4];
                        int unused_stream = -1;
                        for (unsigned stream = 0; stream < 4; ++stream) {
                                if (!info->num_stream_output_components[stream]) {
                                        unused_stream = stream;
                                        break;
                                }
                        }
                        for (unsigned buffer = 0; buffer < 4; ++buffer) {
                                if (stream_for_buffer[buffer] >= 0) {
                                        swizzle[buffer] = stream_for_buffer[buffer];
                                } else {
                                        assert(unused_stream >= 0);
                                        swizzle[buffer] = unused_stream;
                                }
                        }

                        tmp = ac_build_quad_swizzle(&ctx->ac, tmp,
                                swizzle[0], swizzle[1], swizzle[2], swizzle[3]);
                        tmp = LLVMBuildMul(builder, tmp, prim_stride_dw_vgpr, "");

                        LLVMValueRef args[] = {
                                LLVMBuildIntToPtr(builder, ngg_get_ordered_id(ctx), gdsptr, ""),
                                tmp,
                                ctx->i32_0, // ordering
                                ctx->i32_0, // scope
                                ctx->ac.i1false, // isVolatile
                                LLVMConstInt(ctx->i32, 4 << 24, false), // OA index
                                ctx->ac.i1true, // wave release
                                ctx->ac.i1true, // wave done
                        };
                        tmp = ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.ds.ordered.add",
                                                 ctx->i32, args, ARRAY_SIZE(args), 0);

                        /* Keep offsets in a VGPR for quick retrieval via readlane by
                         * the first wave for bounds checking, and also store in LDS
                         * for retrieval by all waves later. */
                        LLVMBuildStore(builder, tmp, offsets_vgpr);

                        tmp2 = LLVMBuildAdd(builder, ac_get_thread_id(&ctx->ac),
                                            scratch_offset_basev, "");
                        tmp2 = ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, tmp2);
                        LLVMBuildStore(builder, tmp, tmp2);
                }
                ac_build_endif(&ctx->ac, 5210);

                /* Determine the max emit per buffer. This is done via the SALU, in part
                 * because LLVM can't generate divide-by-multiply if we try to do this
                 * via VALU with one lane per buffer.
                 */
                LLVMValueRef max_emit[4] = {};
                for (unsigned buffer = 0; buffer < 4; ++buffer) {
                        if (stream_for_buffer[buffer] == -1)
                                continue;

                        LLVMValueRef bufsize_dw =
                                LLVMBuildLShr(builder,
                                        LLVMBuildExtractElement(builder, so_buffer[buffer], i32_2, ""),
                                        i32_2, "");

                        tmp = LLVMBuildLoad(builder, offsets_vgpr, "");
                        LLVMValueRef offset_dw =
                                ac_build_readlane(&ctx->ac, tmp,
                                                LLVMConstInt(ctx->i32, buffer, false));

                        tmp = LLVMBuildSub(builder, bufsize_dw, offset_dw, "");
                        tmp = LLVMBuildUDiv(builder, tmp, prim_stride_dw[buffer], "");

                        tmp2 = LLVMBuildICmp(builder, LLVMIntULT, bufsize_dw, offset_dw, "");
                        max_emit[buffer] = LLVMBuildSelect(builder, tmp2, ctx->i32_0, tmp, "");
                }

                /* Determine the number of emitted primitives per stream and fixup the
                 * GDS counter if necessary.
                 *
                 * This is complicated by the fact that a single stream can emit to
                 * multiple buffers (but luckily not vice versa).
                 */
                LLVMValueRef emit_vgpr = ctx->i32_0;

                for (unsigned stream = 0; stream < 4; ++stream) {
                        if (!info->num_stream_output_components[stream])
                                continue;

                        tmp = LLVMBuildLoad(builder, generated_by_stream_vgpr, "");
                        LLVMValueRef generated =
                                ac_build_readlane(&ctx->ac, tmp,
                                                  LLVMConstInt(ctx->i32, stream, false));

                        LLVMValueRef emit = generated;
                        for (unsigned buffer = 0; buffer < 4; ++buffer) {
                                if (stream_for_buffer[buffer] == stream)
                                        emit = ac_build_umin(&ctx->ac, emit, max_emit[buffer]);
                        }

                        emit_vgpr = ac_build_writelane(&ctx->ac, emit_vgpr, emit,
                                                       LLVMConstInt(ctx->i32, stream, false));

                        /* Fixup the offset using a plain GDS atomic if we overflowed. */
                        tmp = LLVMBuildICmp(builder, LLVMIntULT, emit, generated, "");
                        ac_build_ifcc(&ctx->ac, tmp, 5221); /* scalar branch */
                        tmp = LLVMBuildLShr(builder,
                                            LLVMConstInt(ctx->i32, bufmask_for_stream[stream], false),
                                            ac_get_thread_id(&ctx->ac), "");
                        tmp = LLVMBuildTrunc(builder, tmp, ctx->i1, "");
                        ac_build_ifcc(&ctx->ac, tmp, 5222);
                        {
                                tmp = LLVMBuildSub(builder, generated, emit, "");
                                tmp = LLVMBuildMul(builder, tmp, prim_stride_dw_vgpr, "");
                                tmp2 = LLVMBuildGEP(builder, gdsbase, &tid, 1, "");
                                LLVMBuildAtomicRMW(builder, LLVMAtomicRMWBinOpSub, tmp2, tmp,
                                                   LLVMAtomicOrderingMonotonic, false);
                        }
                        ac_build_endif(&ctx->ac, 5222);
                        ac_build_endif(&ctx->ac, 5221);
                }

                tmp = LLVMBuildICmp(builder, LLVMIntULT, ac_get_thread_id(&ctx->ac), i32_4, "");
                ac_build_ifcc(&ctx->ac, tmp, 5225);
                {
                        tmp = LLVMBuildAdd(builder, ac_get_thread_id(&ctx->ac),
                                           scratch_emit_basev, "");
                        tmp = ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, tmp);
                        LLVMBuildStore(builder, emit_vgpr, tmp);
                }
                ac_build_endif(&ctx->ac, 5225);
        }
        ac_build_endif(&ctx->ac, 5200);

        /* Determine the workgroup-relative per-thread / primitive offset into
         * the streamout buffers */
        struct ac_wg_scan primemit_scan[4] = {};

        if (isgs) {
                for (unsigned stream = 0; stream < 4; ++stream) {
                        if (!info->num_stream_output_components[stream])
                                continue;

                        primemit_scan[stream].enable_exclusive = true;
                        primemit_scan[stream].op = nir_op_iadd;
                        primemit_scan[stream].src = nggso->prim_enable[stream];
                        primemit_scan[stream].scratch =
                                ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch,
                                        LLVMConstInt(ctx->i32, 12 + 8 * stream, false));
                        primemit_scan[stream].waveidx = get_wave_id_in_tg(ctx);
                        primemit_scan[stream].numwaves = get_tgsize(ctx);
                        primemit_scan[stream].maxwaves = 8;
                        ac_build_wg_scan_top(&ctx->ac, &primemit_scan[stream]);
                }
        }

        ac_build_s_barrier(&ctx->ac);

        /* Fetch the per-buffer offsets and per-stream emit counts in all waves. */
        LLVMValueRef wgoffset_dw[4] = {};

        {
                LLVMValueRef scratch_vgpr;

                tmp = ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, ac_get_thread_id(&ctx->ac));
                scratch_vgpr = LLVMBuildLoad(builder, tmp, "");

                for (unsigned buffer = 0; buffer < 4; ++buffer) {
                        if (stream_for_buffer[buffer] >= 0) {
                                wgoffset_dw[buffer] = ac_build_readlane(
                                        &ctx->ac, scratch_vgpr,
                                        LLVMConstInt(ctx->i32, scratch_offset_base + buffer, false));
                        }
                }

                for (unsigned stream = 0; stream < 4; ++stream) {
                        if (info->num_stream_output_components[stream]) {
                                nggso->emit[stream] = ac_build_readlane(
                                        &ctx->ac, scratch_vgpr,
                                        LLVMConstInt(ctx->i32, scratch_emit_base + stream, false));
                        }
                }
        }

        /* Write out primitive data */
        for (unsigned stream = 0; stream < 4; ++stream) {
                if (!info->num_stream_output_components[stream])
                        continue;

                if (isgs) {
                        ac_build_wg_scan_bottom(&ctx->ac, &primemit_scan[stream]);
                } else {
                        primemit_scan[stream].result_exclusive = tid;
                }

                tmp = LLVMBuildICmp(builder, LLVMIntULT,
                                    primemit_scan[stream].result_exclusive,
                                    nggso->emit[stream], "");
                tmp = LLVMBuildAnd(builder, tmp, nggso->prim_enable[stream], "");
                ac_build_ifcc(&ctx->ac, tmp, 5240);
                {
                        LLVMValueRef offset_vtx =
                                LLVMBuildMul(builder, primemit_scan[stream].result_exclusive,
                                             nggso->num_vertices, "");

                        for (unsigned i = 0; i < max_num_vertices; ++i) {
                                tmp = LLVMBuildICmp(builder, LLVMIntULT,
                                                    LLVMConstInt(ctx->i32, i, false),
                                                    nggso->num_vertices, "");
                                ac_build_ifcc(&ctx->ac, tmp, 5241);
                                build_streamout_vertex(ctx, so_buffer, wgoffset_dw,
                                                       stream, offset_vtx, nggso->vertices[i]);
                                ac_build_endif(&ctx->ac, 5241);
                                offset_vtx = LLVMBuildAdd(builder, offset_vtx, ctx->i32_1, "");
                        }
                }
                ac_build_endif(&ctx->ac, 5240);
        }
}

/* 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;

        /* The edgeflag is always stored in the last element that's also
         * used for padding to reduce LDS bank conflicts. */
        if (shader->selector->so.num_outputs)
                lds_vertex_size = 4 * shader->selector->info.num_outputs + 1;
        if (shader->selector->info.writes_edgeflag)
                lds_vertex_size = MAX2(lds_vertex_size, 1);

        /* LDS size for passing data from GS to ES.
         * GS stores Primitive IDs into LDS at the address corresponding
         * to the ES thread of the provoking vertex. All ES threads
         * load and export PrimitiveID for their thread.
         */
        if (shader->selector->type == PIPE_SHADER_VERTEX &&
            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;
}

/**
 * Returns an `[N x i32] addrspace(LDS)*` pointing at contiguous LDS storage
 * for the vertex outputs.
 */
static LLVMValueRef ngg_nogs_vertex_ptr(struct si_shader_context *ctx,
                                        LLVMValueRef vtxid)
{
        /* The extra dword is used to avoid LDS bank conflicts. */
        unsigned vertex_size = ngg_nogs_vertex_size(ctx->shader);
        LLVMTypeRef ai32 = LLVMArrayType(ctx->i32, vertex_size);
        LLVMTypeRef pai32 = LLVMPointerType(ai32, AC_ADDR_SPACE_LDS);
        LLVMValueRef tmp = LLVMBuildBitCast(ctx->ac.builder, ctx->esgs_ring, pai32, "");
        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.
 */
void gfx10_emit_ngg_epilogue(struct ac_shader_abi *abi,
                             unsigned max_outputs,
                             LLVMValueRef *addrs)
{
        struct si_shader_context *ctx = si_shader_context_from_abi(abi);
        struct si_shader_selector *sel = ctx->shader->selector;
        struct si_shader_info *info = &sel->info;
        struct si_shader_output_values outputs[PIPE_MAX_SHADER_OUTPUTS];
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef tmp, tmp2;

        assert(!ctx->shader->is_gs_copy_shader);
        assert(info->num_outputs <= max_outputs);

        LLVMValueRef vertex_ptr = NULL;

        if (sel->so.num_outputs || sel->info.writes_edgeflag)
                vertex_ptr = ngg_nogs_vertex_ptr(ctx, get_thread_id_in_tg(ctx));

        for (unsigned i = 0; i < info->num_outputs; i++) {
                outputs[i].semantic_name = info->output_semantic_name[i];
                outputs[i].semantic_index = info->output_semantic_index[i];

                for (unsigned j = 0; j < 4; j++) {
                        outputs[i].vertex_stream[j] =
                                (info->output_streams[i] >> (2 * j)) & 3;

                        /* TODO: we may store more outputs than streamout needs,
                         * but streamout performance isn't that important.
                         */
                        if (sel->so.num_outputs) {
                                tmp = ac_build_gep0(&ctx->ac, vertex_ptr,
                                        LLVMConstInt(ctx->i32, 4 * i + j, false));
                                tmp2 = LLVMBuildLoad(builder, addrs[4 * i + j], "");
                                tmp2 = ac_to_integer(&ctx->ac, tmp2);
                                LLVMBuildStore(builder, tmp2, tmp);
                        }
                }

                /* Store the edgeflag at the end (if streamout is enabled) */
                if (info->output_semantic_name[i] == TGSI_SEMANTIC_EDGEFLAG &&
                    sel->info.writes_edgeflag) {
                        LLVMValueRef edgeflag = LLVMBuildLoad(builder, addrs[4 * i], "");
                        /* The output is a float, but the hw expects a 1-bit integer. */
                        edgeflag = LLVMBuildFPToUI(ctx->ac.builder, edgeflag, ctx->i32, "");
                        edgeflag = ac_build_umin(&ctx->ac, edgeflag, ctx->i32_1);

                        tmp = LLVMConstInt(ctx->i32, ngg_nogs_vertex_size(ctx->shader) - 1, 0);
                        tmp = ac_build_gep0(&ctx->ac, vertex_ptr, tmp);
                        LLVMBuildStore(builder, edgeflag, tmp);
                }
        }

        bool unterminated_es_if_block =
                !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);

        if (!unterminated_es_if_block)
                ac_build_endif(&ctx->ac, ctx->merged_wrap_if_label);

        LLVMValueRef is_gs_thread = si_is_gs_thread(ctx);
        LLVMValueRef is_es_thread = si_is_es_thread(ctx);
        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;
        LLVMValueRef num_vertices_val = ngg_get_vertices_per_prim(ctx, &num_vertices);

        /* Streamout */
        LLVMValueRef emitted_prims = NULL;

        if (sel->so.num_outputs) {
                assert(!unterminated_es_if_block);

                struct ngg_streamout nggso = {};
                nggso.num_vertices = num_vertices_val;
                nggso.prim_enable[0] = is_gs_thread;

                for (unsigned i = 0; i < num_vertices; ++i)
                        nggso.vertices[i] = ngg_nogs_vertex_ptr(ctx, vtxindex[i]);

                build_streamout(ctx, &nggso);
                emitted_prims = nggso.emit[0];
        }

        LLVMValueRef user_edgeflags[3] = {};

        if (sel->info.writes_edgeflag) {
                assert(!unterminated_es_if_block);

                /* Streamout already inserted the barrier, so don't insert it again. */
                if (!sel->so.num_outputs)
                        ac_build_s_barrier(&ctx->ac);

                ac_build_ifcc(&ctx->ac, is_gs_thread, 5400);
                /* Load edge flags from ES threads and store them into VGPRs in GS threads. */
                for (unsigned i = 0; i < num_vertices; i++) {
                        tmp = ngg_nogs_vertex_ptr(ctx, vtxindex[i]);
                        tmp2 = LLVMConstInt(ctx->i32, ngg_nogs_vertex_size(ctx->shader) - 1, 0);
                        tmp = ac_build_gep0(&ctx->ac, tmp, tmp2);
                        tmp = LLVMBuildLoad(builder, tmp, "");
                        tmp = LLVMBuildTrunc(builder, tmp, ctx->i1, "");

                        user_edgeflags[i] = ac_build_alloca_undef(&ctx->ac, ctx->i1, "");
                        LLVMBuildStore(builder, tmp, user_edgeflags[i]);
                }
                ac_build_endif(&ctx->ac, 5400);
        }

        /* Copy Primitive IDs from GS threads to the LDS address corresponding
         * to the ES thread of the provoking vertex.
         */
        if (ctx->type == PIPE_SHADER_VERTEX &&
            ctx->shader->key.mono.u.vs_export_prim_id) {
                assert(!unterminated_es_if_block);

                /* Streamout and edge flags use LDS. Make it idle, so that we can reuse it. */
                if (sel->so.num_outputs || sel->info.writes_edgeflag)
                        ac_build_s_barrier(&ctx->ac);

                ac_build_ifcc(&ctx->ac, is_gs_thread, 5400);
                /* Extract the PROVOKING_VTX_INDEX field. */
                LLVMValueRef provoking_vtx_in_prim =
                        si_unpack_param(ctx, ctx->vs_state_bits, 4, 2);

                /* provoking_vtx_index = vtxindex[provoking_vtx_in_prim]; */
                LLVMValueRef indices = ac_build_gather_values(&ctx->ac, vtxindex, 3);
                LLVMValueRef provoking_vtx_index =
                        LLVMBuildExtractElement(builder, indices, provoking_vtx_in_prim, "");
                LLVMValueRef vertex_ptr = ngg_nogs_vertex_ptr(ctx, provoking_vtx_index);

                LLVMBuildStore(builder, ac_get_arg(&ctx->ac, ctx->args.gs_prim_id),
                               ac_build_gep0(&ctx->ac, vertex_ptr, ctx->i32_0));
                ac_build_endif(&ctx->ac, 5400);
        }

        /* Update query buffer */
        if (ctx->screen->use_ngg_streamout &&
            !info->properties[TGSI_PROPERTY_VS_BLIT_SGPRS_AMD]) {
                assert(!unterminated_es_if_block);

                tmp = si_unpack_param(ctx, ctx->vs_state_bits, 6, 1);
                tmp = LLVMBuildTrunc(builder, tmp, ctx->i1, "");
                ac_build_ifcc(&ctx->ac, tmp, 5029); /* if (STREAMOUT_QUERY_ENABLED) */
                tmp = LLVMBuildICmp(builder, LLVMIntEQ, get_wave_id_in_tg(ctx), ctx->ac.i32_0, "");
                ac_build_ifcc(&ctx->ac, tmp, 5030);
                tmp = LLVMBuildICmp(builder, LLVMIntULE, ac_get_thread_id(&ctx->ac),
                                    sel->so.num_outputs ? ctx->ac.i32_1 : ctx->ac.i32_0, "");
                ac_build_ifcc(&ctx->ac, tmp, 5031);
                {
                        LLVMValueRef args[] = {
                                ngg_get_prim_cnt(ctx),
                                ngg_get_query_buf(ctx),
                                LLVMConstInt(ctx->i32, 16, false), /* offset of stream[0].generated_primitives */
                                ctx->i32_0, /* soffset */
                                ctx->i32_0, /* cachepolicy */
                        };

                        if (sel->so.num_outputs) {
                                args[0] = ac_build_writelane(&ctx->ac, args[0], emitted_prims, ctx->i32_1);
                                args[2] = ac_build_writelane(&ctx->ac, args[2],
                                                LLVMConstInt(ctx->i32, 24, false), ctx->i32_1);
                        }

                        /* TODO: should this be 64-bit atomics? */
                        ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.raw.buffer.atomic.add.i32",
                                           ctx->i32, args, 5, 0);
                }
                ac_build_endif(&ctx->ac, 5031);
                ac_build_endif(&ctx->ac, 5030);
                ac_build_endif(&ctx->ac, 5029);
        }

        /* 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, NULL);
        }

        /* Export per-vertex data (positions and parameters). */
        if (!unterminated_es_if_block)
                ac_build_ifcc(&ctx->ac, is_es_thread, 6002);
        {
                unsigned i;

                /* Unconditionally (re-)load the values for proper SSA form. */
                for (i = 0; i < info->num_outputs; i++) {
                        /* 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], "");
                                }
                        }
                }

                if (ctx->shader->key.mono.u.vs_export_prim_id) {
                        outputs[i].semantic_name = TGSI_SEMANTIC_PRIMID;
                        outputs[i].semantic_index = 0;

                        if (ctx->type == PIPE_SHADER_VERTEX) {
                                /* Wait for GS stores to finish. */
                                ac_build_s_barrier(&ctx->ac);

                                tmp = ngg_nogs_vertex_ptr(ctx, get_thread_id_in_tg(ctx));
                                tmp = ac_build_gep0(&ctx->ac, tmp, ctx->i32_0);
                                outputs[i].values[0] = LLVMBuildLoad(builder, tmp, "");
                        } else {
                                assert(ctx->type == PIPE_SHADER_TESS_EVAL);
                                outputs[i].values[0] = si_get_primitive_id(ctx, 0);
                        }

                        outputs[i].values[0] = ac_to_float(&ctx->ac, outputs[i].values[0]);
                        for (unsigned j = 1; j < 4; j++)
                                outputs[i].values[j] = LLVMGetUndef(ctx->f32);

                        memset(outputs[i].vertex_stream, 0,
                               sizeof(outputs[i].vertex_stream));
                        i++;
                }

                si_llvm_export_vs(ctx, outputs, i);
        }
        ac_build_endif(&ctx->ac, 6002);
}

static LLVMValueRef
ngg_gs_get_vertex_storage(struct si_shader_context *ctx)
{
        const struct si_shader_selector *sel = ctx->shader->selector;
        const struct si_shader_info *info = &sel->info;

        LLVMTypeRef elements[2] = {
                LLVMArrayType(ctx->ac.i32, 4 * info->num_outputs),
                LLVMArrayType(ctx->ac.i8, 4),
        };
        LLVMTypeRef type = LLVMStructTypeInContext(ctx->ac.context, elements, 2, false);
        type = LLVMPointerType(LLVMArrayType(type, 0), AC_ADDR_SPACE_LDS);
        return LLVMBuildBitCast(ctx->ac.builder, ctx->gs_ngg_emit, type, "");
}

/**
 * Return a pointer to the LDS storage reserved for the N'th vertex, where N
 * is in emit order; that is:
 * - during the epilogue, N is the threadidx (relative to the entire threadgroup)
 * - during vertex emit, i.e. while the API GS shader invocation is running,
 *   N = threadidx * gs_max_out_vertices + emitidx
 *
 * Goals of the LDS memory layout:
 * 1. Eliminate bank conflicts on write for geometry shaders that have all emits
 *    in uniform control flow
 * 2. Eliminate bank conflicts on read for export if, additionally, there is no
 *    culling
 * 3. Agnostic to the number of waves (since we don't know it before compiling)
 * 4. Allow coalescing of LDS instructions (ds_write_b128 etc.)
 * 5. Avoid wasting memory.
 *
 * We use an AoS layout due to point 4 (this also helps point 3). In an AoS
 * layout, elimination of bank conflicts requires that each vertex occupy an
 * odd number of dwords. We use the additional dword to store the output stream
 * index as well as a flag to indicate whether this vertex ends a primitive
 * for rasterization.
 *
 * Swizzling is required to satisfy points 1 and 2 simultaneously.
 *
 * Vertices are stored in export order (gsthread * gs_max_out_vertices + emitidx).
 * Indices are swizzled in groups of 32, which ensures point 1 without
 * disturbing point 2.
 *
 * \return an LDS pointer to type {[N x i32], [4 x i8]}
 */
static LLVMValueRef
ngg_gs_vertex_ptr(struct si_shader_context *ctx, LLVMValueRef vertexidx)
{
        struct si_shader_selector *sel = ctx->shader->selector;
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef storage = ngg_gs_get_vertex_storage(ctx);

        /* gs_max_out_vertices = 2^(write_stride_2exp) * some odd number */
        unsigned write_stride_2exp = ffs(sel->gs_max_out_vertices) - 1;
        if (write_stride_2exp) {
                LLVMValueRef row =
                        LLVMBuildLShr(builder, vertexidx,
                                      LLVMConstInt(ctx->ac.i32, 5, false), "");
                LLVMValueRef swizzle =
                        LLVMBuildAnd(builder, row,
                                     LLVMConstInt(ctx->ac.i32, (1u << write_stride_2exp) - 1,
                                                  false), "");
                vertexidx = LLVMBuildXor(builder, vertexidx, swizzle, "");
        }

        return ac_build_gep0(&ctx->ac, storage, vertexidx);
}

static LLVMValueRef
ngg_gs_emit_vertex_ptr(struct si_shader_context *ctx, LLVMValueRef gsthread,
                       LLVMValueRef emitidx)
{
        struct si_shader_selector *sel = ctx->shader->selector;
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef tmp;

        tmp = LLVMConstInt(ctx->ac.i32, sel->gs_max_out_vertices, false);
        tmp = LLVMBuildMul(builder, tmp, gsthread, "");
        const LLVMValueRef vertexidx = LLVMBuildAdd(builder, tmp, emitidx, "");
        return ngg_gs_vertex_ptr(ctx, vertexidx);
}

static LLVMValueRef
ngg_gs_get_emit_output_ptr(struct si_shader_context *ctx, LLVMValueRef vertexptr,
                           unsigned out_idx)
{
        LLVMValueRef gep_idx[3] = {
                ctx->ac.i32_0, /* implied C-style array */
                ctx->ac.i32_0, /* first struct entry */
                LLVMConstInt(ctx->ac.i32, out_idx, false),
        };
        return LLVMBuildGEP(ctx->ac.builder, vertexptr, gep_idx, 3, "");
}

static LLVMValueRef
ngg_gs_get_emit_primflag_ptr(struct si_shader_context *ctx, LLVMValueRef vertexptr,
                             unsigned stream)
{
        LLVMValueRef gep_idx[3] = {
                ctx->ac.i32_0, /* implied C-style array */
                ctx->ac.i32_1, /* second struct entry */
                LLVMConstInt(ctx->ac.i32, stream, false),
        };
        return LLVMBuildGEP(ctx->ac.builder, vertexptr, gep_idx, 3, "");
}

void gfx10_ngg_gs_emit_vertex(struct si_shader_context *ctx,
                              unsigned stream,
                              LLVMValueRef *addrs)
{
        const struct si_shader_selector *sel = ctx->shader->selector;
        const struct si_shader_info *info = &sel->info;
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef tmp;
        const LLVMValueRef vertexidx =
                LLVMBuildLoad(builder, ctx->gs_next_vertex[stream], "");

        /* If this thread has already emitted the declared maximum number of
         * vertices, skip the write: excessive vertex emissions are not
         * supposed to have any effect.
         */
        const LLVMValueRef can_emit =
                LLVMBuildICmp(builder, LLVMIntULT, vertexidx,
                              LLVMConstInt(ctx->i32, sel->gs_max_out_vertices, false), "");

        tmp = LLVMBuildAdd(builder, vertexidx, ctx->ac.i32_1, "");
        tmp = LLVMBuildSelect(builder, can_emit, tmp, vertexidx, "");
        LLVMBuildStore(builder, tmp, ctx->gs_next_vertex[stream]);

        ac_build_ifcc(&ctx->ac, can_emit, 9001);

        const LLVMValueRef vertexptr =
                ngg_gs_emit_vertex_ptr(ctx, get_thread_id_in_tg(ctx), vertexidx);
        unsigned out_idx = 0;
        for (unsigned i = 0; i < info->num_outputs; i++) {
                for (unsigned chan = 0; chan < 4; chan++, out_idx++) {
                        if (!(info->output_usagemask[i] & (1 << chan)) ||
                            ((info->output_streams[i] >> (2 * chan)) & 3) != stream)
                                continue;

                        LLVMValueRef out_val = LLVMBuildLoad(builder, addrs[4 * i + chan], "");
                        out_val = ac_to_integer(&ctx->ac, out_val);
                        LLVMBuildStore(builder, out_val,
                                       ngg_gs_get_emit_output_ptr(ctx, vertexptr, out_idx));
                }
        }
        assert(out_idx * 4 == sel->gsvs_vertex_size);

        /* Determine and store whether this vertex completed a primitive. */
        const LLVMValueRef curverts = LLVMBuildLoad(builder, ctx->gs_curprim_verts[stream], "");

        tmp = LLVMConstInt(ctx->ac.i32, u_vertices_per_prim(sel->gs_output_prim) - 1, false);
        const LLVMValueRef iscompleteprim =
                LLVMBuildICmp(builder, LLVMIntUGE, curverts, tmp, "");

        /* Since the geometry shader emits triangle strips, we need to
         * track which primitive is odd and swap vertex indices to get
         * the correct vertex order.
         */
        LLVMValueRef is_odd = ctx->i1false;
        if (stream == 0 && u_vertices_per_prim(sel->gs_output_prim) == 3) {
                tmp = LLVMBuildAnd(builder, curverts, ctx->i32_1, "");
                is_odd = LLVMBuildICmp(builder, LLVMIntEQ, tmp, ctx->i32_1, "");
        }

        tmp = LLVMBuildAdd(builder, curverts, ctx->ac.i32_1, "");
        LLVMBuildStore(builder, tmp, ctx->gs_curprim_verts[stream]);

        /* The per-vertex primitive flag encoding:
         *   bit 0: whether this vertex finishes a primitive
         *   bit 1: whether the primitive is odd (if we are emitting triangle strips)
         */
        tmp = LLVMBuildZExt(builder, iscompleteprim, ctx->ac.i8, "");
        tmp = LLVMBuildOr(builder, tmp,
                          LLVMBuildShl(builder,
                                       LLVMBuildZExt(builder, is_odd, ctx->ac.i8, ""),
                                       ctx->ac.i8_1, ""), "");
        LLVMBuildStore(builder, tmp, ngg_gs_get_emit_primflag_ptr(ctx, vertexptr, stream));

        tmp = LLVMBuildLoad(builder, ctx->gs_generated_prims[stream], "");
        tmp = LLVMBuildAdd(builder, tmp, LLVMBuildZExt(builder, iscompleteprim, ctx->ac.i32, ""), "");
        LLVMBuildStore(builder, tmp, ctx->gs_generated_prims[stream]);

        ac_build_endif(&ctx->ac, 9001);
}

void gfx10_ngg_gs_emit_prologue(struct si_shader_context *ctx)
{
        /* Zero out the part of LDS scratch that is used to accumulate the
         * per-stream generated primitive count.
         */
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef scratchptr = ctx->gs_ngg_scratch;
        LLVMValueRef tid = get_thread_id_in_tg(ctx);
        LLVMValueRef tmp;

        tmp = LLVMBuildICmp(builder, LLVMIntULT, tid, LLVMConstInt(ctx->i32, 4, false), "");
        ac_build_ifcc(&ctx->ac, tmp, 5090);
        {
                LLVMValueRef ptr = ac_build_gep0(&ctx->ac, scratchptr, tid);
                LLVMBuildStore(builder, ctx->i32_0, ptr);
        }
        ac_build_endif(&ctx->ac, 5090);

        ac_build_s_barrier(&ctx->ac);
}

void gfx10_ngg_gs_emit_epilogue(struct si_shader_context *ctx)
{
        const struct si_shader_selector *sel = ctx->shader->selector;
        const struct si_shader_info *info = &sel->info;
        const unsigned verts_per_prim = u_vertices_per_prim(sel->gs_output_prim);
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef i8_0 = LLVMConstInt(ctx->ac.i8, 0, false);
        LLVMValueRef tmp, tmp2;

        /* Zero out remaining (non-emitted) primitive flags.
         *
         * Note: Alternatively, we could pass the relevant gs_next_vertex to
         *       the emit threads via LDS. This is likely worse in the expected
         *       typical case where each GS thread emits the full set of
         *       vertices.
         */
        for (unsigned stream = 0; stream < 4; ++stream) {
                if (!info->num_stream_output_components[stream])
                        continue;

                const LLVMValueRef gsthread = get_thread_id_in_tg(ctx);

                ac_build_bgnloop(&ctx->ac, 5100);

                const LLVMValueRef vertexidx =
                        LLVMBuildLoad(builder, ctx->gs_next_vertex[stream], "");
                tmp = LLVMBuildICmp(builder, LLVMIntUGE, vertexidx,
                        LLVMConstInt(ctx->ac.i32, sel->gs_max_out_vertices, false), "");
                ac_build_ifcc(&ctx->ac, tmp, 5101);
                ac_build_break(&ctx->ac);
                ac_build_endif(&ctx->ac, 5101);

                tmp = LLVMBuildAdd(builder, vertexidx, ctx->ac.i32_1, "");
                LLVMBuildStore(builder, tmp, ctx->gs_next_vertex[stream]);

                tmp = ngg_gs_emit_vertex_ptr(ctx, gsthread, vertexidx);
                LLVMBuildStore(builder, i8_0, ngg_gs_get_emit_primflag_ptr(ctx, tmp, stream));

                ac_build_endloop(&ctx->ac, 5100);
        }

        /* Accumulate generated primitives counts across the entire threadgroup. */
        for (unsigned stream = 0; stream < 4; ++stream) {
                if (!info->num_stream_output_components[stream])
                        continue;

                LLVMValueRef numprims =
                        LLVMBuildLoad(builder, ctx->gs_generated_prims[stream], "");
                numprims = ac_build_reduce(&ctx->ac, numprims, nir_op_iadd, ctx->ac.wave_size);

                tmp = LLVMBuildICmp(builder, LLVMIntEQ, ac_get_thread_id(&ctx->ac), ctx->i32_0, "");
                ac_build_ifcc(&ctx->ac, tmp, 5105);
                {
                        LLVMBuildAtomicRMW(builder, LLVMAtomicRMWBinOpAdd,
                                           ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch,
                                                         LLVMConstInt(ctx->i32, stream, false)),
                                           numprims, LLVMAtomicOrderingMonotonic, false);
                }
                ac_build_endif(&ctx->ac, 5105);
        }

        ac_build_endif(&ctx->ac, ctx->merged_wrap_if_label);

        ac_build_s_barrier(&ctx->ac);

        const LLVMValueRef tid = get_thread_id_in_tg(ctx);
        LLVMValueRef num_emit_threads = ngg_get_prim_cnt(ctx);

        /* Streamout */
        if (sel->so.num_outputs) {
                struct ngg_streamout nggso = {};

                nggso.num_vertices = LLVMConstInt(ctx->i32, verts_per_prim, false);

                LLVMValueRef vertexptr = ngg_gs_vertex_ptr(ctx, tid);
                for (unsigned stream = 0; stream < 4; ++stream) {
                        if (!info->num_stream_output_components[stream])
                                continue;

                        tmp = LLVMBuildLoad(builder, ngg_gs_get_emit_primflag_ptr(ctx, vertexptr, stream), "");
                        tmp = LLVMBuildTrunc(builder, tmp, ctx->i1, "");
                        tmp2 = LLVMBuildICmp(builder, LLVMIntULT, tid, num_emit_threads, "");
                        nggso.prim_enable[stream] = LLVMBuildAnd(builder, tmp, tmp2, "");
                }

                for (unsigned i = 0; i < verts_per_prim; ++i) {
                        tmp = LLVMBuildSub(builder, tid,
                                           LLVMConstInt(ctx->i32, verts_per_prim - i - 1, false), "");
                        tmp = ngg_gs_vertex_ptr(ctx, tmp);
                        nggso.vertices[i] = ac_build_gep0(&ctx->ac, tmp, ctx->i32_0);
                }

                build_streamout(ctx, &nggso);
        }

        /* Write shader query data. */
        if (ctx->screen->use_ngg_streamout) {
                tmp = si_unpack_param(ctx, ctx->vs_state_bits, 6, 1);
                tmp = LLVMBuildTrunc(builder, tmp, ctx->i1, "");
                ac_build_ifcc(&ctx->ac, tmp, 5109); /* if (STREAMOUT_QUERY_ENABLED) */
                unsigned num_query_comps = sel->so.num_outputs ? 8 : 4;
                tmp = LLVMBuildICmp(builder, LLVMIntULT, tid,
                                    LLVMConstInt(ctx->i32, num_query_comps, false), "");
                ac_build_ifcc(&ctx->ac, tmp, 5110);
                {
                        LLVMValueRef offset;
                        tmp = tid;
                        if (sel->so.num_outputs)
                                tmp = LLVMBuildAnd(builder, tmp, LLVMConstInt(ctx->i32, 3, false), "");
                        offset = LLVMBuildNUWMul(builder, tmp, LLVMConstInt(ctx->i32, 32, false), "");
                        if (sel->so.num_outputs) {
                                tmp = LLVMBuildLShr(builder, tid, LLVMConstInt(ctx->i32, 2, false), "");
                                tmp = LLVMBuildNUWMul(builder, tmp, LLVMConstInt(ctx->i32, 8, false), "");
                                offset = LLVMBuildAdd(builder, offset, tmp, "");
                        }

                        tmp = LLVMBuildLoad(builder, ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, tid), "");
                        LLVMValueRef args[] = {
                                tmp,
                                ngg_get_query_buf(ctx),
                                offset,
                                LLVMConstInt(ctx->i32, 16, false), /* soffset */
                                ctx->i32_0, /* cachepolicy */
                        };
                        ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.raw.buffer.atomic.add.i32",
                                           ctx->i32, args, 5, 0);
                }
                ac_build_endif(&ctx->ac, 5110);
                ac_build_endif(&ctx->ac, 5109);
        }

        /* Determine vertex liveness. */
        LLVMValueRef vertliveptr = ac_build_alloca(&ctx->ac, ctx->ac.i1, "vertexlive");

        tmp = LLVMBuildICmp(builder, LLVMIntULT, tid, num_emit_threads, "");
        ac_build_ifcc(&ctx->ac, tmp, 5120);
        {
                for (unsigned i = 0; i < verts_per_prim; ++i) {
                        const LLVMValueRef primidx =
                                LLVMBuildAdd(builder, tid,
                                             LLVMConstInt(ctx->ac.i32, i, false), "");

                        if (i > 0) {
                                tmp = LLVMBuildICmp(builder, LLVMIntULT, primidx, num_emit_threads, "");
                                ac_build_ifcc(&ctx->ac, tmp, 5121 + i);
                        }

                        /* Load primitive liveness */
                        tmp = ngg_gs_vertex_ptr(ctx, primidx);
                        tmp = LLVMBuildLoad(builder, ngg_gs_get_emit_primflag_ptr(ctx, tmp, 0), "");
                        const LLVMValueRef primlive =
                                LLVMBuildTrunc(builder, tmp, ctx->ac.i1, "");

                        tmp = LLVMBuildLoad(builder, vertliveptr, "");
                        tmp = LLVMBuildOr(builder, tmp, primlive, ""),
                        LLVMBuildStore(builder, tmp, vertliveptr);

                        if (i > 0)
                                ac_build_endif(&ctx->ac, 5121 + i);
                }
        }
        ac_build_endif(&ctx->ac, 5120);

        /* Inclusive scan addition across the current wave. */
        LLVMValueRef vertlive = LLVMBuildLoad(builder, vertliveptr, "");
        struct ac_wg_scan vertlive_scan = {};
        vertlive_scan.op = nir_op_iadd;
        vertlive_scan.enable_reduce = true;
        vertlive_scan.enable_exclusive = true;
        vertlive_scan.src = vertlive;
        vertlive_scan.scratch = ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, ctx->i32_0);
        vertlive_scan.waveidx = get_wave_id_in_tg(ctx);
        vertlive_scan.numwaves = get_tgsize(ctx);
        vertlive_scan.maxwaves = 8;

        ac_build_wg_scan(&ctx->ac, &vertlive_scan);

        /* Skip all exports (including index exports) when possible. At least on
         * early gfx10 revisions this is also to avoid hangs.
         */
        LLVMValueRef have_exports =
                LLVMBuildICmp(builder, LLVMIntNE, vertlive_scan.result_reduce, ctx->ac.i32_0, "");
        num_emit_threads =
                LLVMBuildSelect(builder, have_exports, num_emit_threads, ctx->ac.i32_0, "");

        /* Allocate export space. Send this message as early as possible, to
         * hide the latency of the SQ <-> SPI roundtrip.
         *
         * Note: We could consider compacting primitives for export as well.
         *       PA processes 1 non-null prim / clock, but it fetches 4 DW of
         *       prim data per clock and skips null primitives at no additional
         *       cost. So compacting primitives can only be beneficial when
         *       there are 4 or more contiguous null primitives in the export
         *       (in the common case of single-dword prim exports).
         */
        ac_build_sendmsg_gs_alloc_req(&ctx->ac, get_wave_id_in_tg(ctx),
                                      vertlive_scan.result_reduce, num_emit_threads);

        /* Setup the reverse vertex compaction permutation. We re-use stream 1
         * of the primitive liveness flags, relying on the fact that each
         * threadgroup can have at most 256 threads. */
        ac_build_ifcc(&ctx->ac, vertlive, 5130);
        {
                tmp = ngg_gs_vertex_ptr(ctx, vertlive_scan.result_exclusive);
                tmp2 = LLVMBuildTrunc(builder, tid, ctx->ac.i8, "");
                LLVMBuildStore(builder, tmp2, ngg_gs_get_emit_primflag_ptr(ctx, tmp, 1));
        }
        ac_build_endif(&ctx->ac, 5130);

        ac_build_s_barrier(&ctx->ac);

        /* Export primitive data */
        tmp = LLVMBuildICmp(builder, LLVMIntULT, tid, num_emit_threads, "");
        ac_build_ifcc(&ctx->ac, tmp, 5140);
        {
                LLVMValueRef flags;
                struct ac_ngg_prim prim = {};
                prim.num_vertices = verts_per_prim;

                tmp = ngg_gs_vertex_ptr(ctx, tid);
                flags = LLVMBuildLoad(builder, ngg_gs_get_emit_primflag_ptr(ctx, tmp, 0), "");
                prim.isnull = LLVMBuildNot(builder, LLVMBuildTrunc(builder, flags, ctx->i1, ""), "");

                for (unsigned i = 0; i < verts_per_prim; ++i) {
                        prim.index[i] = LLVMBuildSub(builder, vertlive_scan.result_exclusive,
                                LLVMConstInt(ctx->ac.i32, verts_per_prim - i - 1, false), "");
                        prim.edgeflag[i] = ctx->ac.i1false;
                }

                /* Geometry shaders output triangle strips, but NGG expects triangles. */
                if (verts_per_prim == 3) {
                        LLVMValueRef is_odd = LLVMBuildLShr(builder, flags, ctx->ac.i8_1, "");
                        is_odd = LLVMBuildTrunc(builder, is_odd, ctx->i1, "");
                        LLVMValueRef flatshade_first =
                                LLVMBuildICmp(builder, LLVMIntEQ,
                                              si_unpack_param(ctx, ctx->vs_state_bits, 4, 2),
                                              ctx->i32_0, "");

                        ac_build_triangle_strip_indices_to_triangle(&ctx->ac, is_odd,
                                                                    flatshade_first,
                                                                    prim.index);
                }

                ac_build_export_prim(&ctx->ac, &prim);
        }
        ac_build_endif(&ctx->ac, 5140);

        /* Export position and parameter data */
        tmp = LLVMBuildICmp(builder, LLVMIntULT, tid, vertlive_scan.result_reduce, "");
        ac_build_ifcc(&ctx->ac, tmp, 5145);
        {
                struct si_shader_output_values outputs[PIPE_MAX_SHADER_OUTPUTS];

                tmp = ngg_gs_vertex_ptr(ctx, tid);
                tmp = LLVMBuildLoad(builder, ngg_gs_get_emit_primflag_ptr(ctx, tmp, 1), "");
                tmp = LLVMBuildZExt(builder, tmp, ctx->ac.i32, "");
                const LLVMValueRef vertexptr = ngg_gs_vertex_ptr(ctx, tmp);

                unsigned out_idx = 0;
                for (unsigned i = 0; i < info->num_outputs; i++) {
                        outputs[i].semantic_name = info->output_semantic_name[i];
                        outputs[i].semantic_index = info->output_semantic_index[i];

                        for (unsigned j = 0; j < 4; j++, out_idx++) {
                                tmp = ngg_gs_get_emit_output_ptr(ctx, vertexptr, out_idx);
                                tmp = LLVMBuildLoad(builder, tmp, "");
                                outputs[i].values[j] = ac_to_float(&ctx->ac, tmp);
                                outputs[i].vertex_stream[j] =
                                        (info->output_streams[i] >> (2 * j)) & 3;
                        }
                }

                si_llvm_export_vs(ctx, outputs, info->num_outputs);
        }
        ac_build_endif(&ctx->ac, 5145);
}

static void clamp_gsprims_to_esverts(unsigned *max_gsprims, unsigned max_esverts,
                                     unsigned min_verts_per_prim, bool use_adjacency)
{
        unsigned max_reuse = max_esverts - min_verts_per_prim;
        if (use_adjacency)
                max_reuse /= 2;
        *max_gsprims = MIN2(*max_gsprims, 1 + max_reuse);
}

/**
 * Determine subgroup information like maximum number of vertices and prims.
 *
 * This happens before the shader is uploaded, since LDS relocations during
 * upload depend on the subgroup size.
 */
void gfx10_ngg_calculate_subgroup_info(struct si_shader *shader)
{
        const struct si_shader_selector *gs_sel = shader->selector;
        const struct si_shader_selector *es_sel =
                shader->previous_stage_sel ? shader->previous_stage_sel : gs_sel;
        const enum pipe_shader_type gs_type = gs_sel->type;
        const unsigned gs_num_invocations = MAX2(gs_sel->gs_num_invocations, 1);
        const unsigned input_prim = si_get_input_prim(gs_sel);
        const bool use_adjacency = input_prim >= PIPE_PRIM_LINES_ADJACENCY &&
                                   input_prim <= PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY;
        const unsigned max_verts_per_prim = u_vertices_per_prim(input_prim);
        const unsigned min_verts_per_prim =
                gs_type == PIPE_SHADER_GEOMETRY ? max_verts_per_prim : 1;

        /* All these are in dwords: */
        /* We can't allow using the whole LDS, because GS waves compete with
         * other shader stages for LDS space.
         *
         * TODO: We should really take the shader's internal LDS use into
         *       account. The linker will fail if the size is greater than
         *       8K dwords.
         */
        const unsigned max_lds_size = 8 * 1024 - 768;
        const unsigned target_lds_size = max_lds_size;
        unsigned esvert_lds_size = 0;
        unsigned gsprim_lds_size = 0;

        /* All these are per subgroup: */
        bool max_vert_out_per_gs_instance = false;
        unsigned max_esverts_base = 128;
        unsigned max_gsprims_base = 128; /* default prim group size clamp */

        /* Hardware has the following non-natural restrictions on the value
         * of GE_CNTL.VERT_GRP_SIZE based on based on the primitive type of
         * the draw:
         *  - at most 252 for any line input primitive type
         *  - at most 251 for any quad input primitive type
         *  - at most 251 for triangle strips with adjacency (this happens to
         *    be the natural limit for triangle *lists* with adjacency)
         */
        max_esverts_base = MIN2(max_esverts_base, 251 + max_verts_per_prim - 1);

        if (gs_type == PIPE_SHADER_GEOMETRY) {
                unsigned max_out_verts_per_gsprim =
                        gs_sel->gs_max_out_vertices * gs_num_invocations;

                if (max_out_verts_per_gsprim <= 256) {
                        if (max_out_verts_per_gsprim) {
                                max_gsprims_base = MIN2(max_gsprims_base,
                                                        256 / max_out_verts_per_gsprim);
                        }
                } else {
                        /* Use special multi-cycling mode in which each GS
                         * instance gets its own subgroup. Does not work with
                         * tessellation. */
                        max_vert_out_per_gs_instance = true;
                        max_gsprims_base = 1;
                        max_out_verts_per_gsprim = gs_sel->gs_max_out_vertices;
                }

                esvert_lds_size = es_sel->esgs_itemsize / 4;
                gsprim_lds_size = (gs_sel->gsvs_vertex_size / 4 + 1) * max_out_verts_per_gsprim;
        } else {
                /* VS and TES. */
                /* LDS size for passing data from ES to GS. */
                esvert_lds_size = ngg_nogs_vertex_size(shader);
        }

        unsigned max_gsprims = max_gsprims_base;
        unsigned max_esverts = max_esverts_base;

        if (esvert_lds_size)
                max_esverts = MIN2(max_esverts, target_lds_size / esvert_lds_size);
        if (gsprim_lds_size)
                max_gsprims = MIN2(max_gsprims, target_lds_size / gsprim_lds_size);

        max_esverts = MIN2(max_esverts, max_gsprims * max_verts_per_prim);
        clamp_gsprims_to_esverts(&max_gsprims, max_esverts, min_verts_per_prim, use_adjacency);
        assert(max_esverts >= max_verts_per_prim && max_gsprims >= 1);

        if (esvert_lds_size || gsprim_lds_size) {
                /* Now that we have a rough proportionality between esverts
                 * and gsprims based on the primitive type, scale both of them
                 * down simultaneously based on required LDS space.
                 *
                 * We could be smarter about this if we knew how much vertex
                 * reuse to expect.
                 */
                unsigned lds_total = max_esverts * esvert_lds_size +
                                     max_gsprims * gsprim_lds_size;
                if (lds_total > target_lds_size) {
                        max_esverts = max_esverts * target_lds_size / lds_total;
                        max_gsprims = max_gsprims * target_lds_size / lds_total;

                        max_esverts = MIN2(max_esverts, max_gsprims * max_verts_per_prim);
                        clamp_gsprims_to_esverts(&max_gsprims, max_esverts,
                                                 min_verts_per_prim, use_adjacency);
                        assert(max_esverts >= max_verts_per_prim && max_gsprims >= 1);
                }
        }

        /* Round up towards full wave sizes for better ALU utilization. */
        if (!max_vert_out_per_gs_instance) {
                const unsigned wavesize = gs_sel->screen->ge_wave_size;
                unsigned orig_max_esverts;
                unsigned orig_max_gsprims;
                do {
                        orig_max_esverts = max_esverts;
                        orig_max_gsprims = max_gsprims;

                        max_esverts = align(max_esverts, wavesize);
                        max_esverts = MIN2(max_esverts, max_esverts_base);
                        if (esvert_lds_size)
                                max_esverts = MIN2(max_esverts,
                                                   (max_lds_size - max_gsprims * gsprim_lds_size) /
                                                   esvert_lds_size);
                        max_esverts = MIN2(max_esverts, max_gsprims * max_verts_per_prim);

                        max_gsprims = align(max_gsprims, wavesize);
                        max_gsprims = MIN2(max_gsprims, max_gsprims_base);
                        if (gsprim_lds_size)
                                max_gsprims = MIN2(max_gsprims,
                                                   (max_lds_size - max_esverts * esvert_lds_size) /
                                                   gsprim_lds_size);
                        clamp_gsprims_to_esverts(&max_gsprims, max_esverts,
                                                 min_verts_per_prim, use_adjacency);
                        assert(max_esverts >= max_verts_per_prim && max_gsprims >= 1);
                } while (orig_max_esverts != max_esverts || orig_max_gsprims != max_gsprims);
        }

        /* Hardware restriction: minimum value of max_esverts */
        max_esverts = MAX2(max_esverts, 23 + max_verts_per_prim);

        unsigned max_out_vertices =
                max_vert_out_per_gs_instance ? gs_sel->gs_max_out_vertices :
                gs_type == PIPE_SHADER_GEOMETRY ?
                max_gsprims * gs_num_invocations * gs_sel->gs_max_out_vertices :
                max_esverts;
        assert(max_out_vertices <= 256);

        unsigned prim_amp_factor = 1;
        if (gs_type == PIPE_SHADER_GEOMETRY) {
                /* Number of output primitives per GS input primitive after
                 * GS instancing. */
                prim_amp_factor = gs_sel->gs_max_out_vertices;
        }

        /* The GE only checks against the maximum number of ES verts after
         * allocating a full GS primitive. So we need to ensure that whenever
         * this check passes, there is enough space for a full primitive without
         * vertex reuse.
         */
        shader->ngg.hw_max_esverts = max_esverts - max_verts_per_prim + 1;
        shader->ngg.max_gsprims = max_gsprims;
        shader->ngg.max_out_verts = max_out_vertices;
        shader->ngg.prim_amp_factor = prim_amp_factor;
        shader->ngg.max_vert_out_per_gs_instance = max_vert_out_per_gs_instance;

        shader->gs_info.esgs_ring_size = 4 * max_esverts * esvert_lds_size;
        shader->ngg.ngg_emit_size = max_gsprims * gsprim_lds_size;

        assert(shader->ngg.hw_max_esverts >= 24); /* HW limitation */
}