Merge remote-tracking branch 'public/master' into vulkan

[mesa.git] / src / gallium / drivers / freedreno / ir3 / ir3_compiler_nir.c

/* -*- mode: C; c-file-style: "k&r"; tab-width 4; indent-tabs-mode: t; -*- */

/*
 * Copyright (C) 2015 Rob Clark <robclark@freedesktop.org>
 *
 * 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
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS 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.
 *
 * Authors:
 *    Rob Clark <robclark@freedesktop.org>
 */

#include <stdarg.h>

#include "pipe/p_state.h"
#include "util/u_string.h"
#include "util/u_memory.h"
#include "util/u_inlines.h"

#include "freedreno_util.h"

#include "ir3_compiler.h"
#include "ir3_shader.h"
#include "ir3_nir.h"

#include "instr-a3xx.h"
#include "ir3.h"


struct ir3_compile {
        struct ir3_compiler *compiler;

        struct nir_shader *s;

        struct ir3 *ir;
        struct ir3_shader_variant *so;

        struct ir3_block *block;      /* the current block */
        struct ir3_block *in_block;   /* block created for shader inputs */

        nir_function_impl *impl;

        /* For fragment shaders, from the hw perspective the only
         * actual input is r0.xy position register passed to bary.f.
         * But TGSI doesn't know that, it still declares things as
         * IN[] registers.  So we do all the input tracking normally
         * and fix things up after compile_instructions()
         *
         * NOTE that frag_pos is the hardware position (possibly it
         * is actually an index or tag or some such.. it is *not*
         * values that can be directly used for gl_FragCoord..)
         */
        struct ir3_instruction *frag_pos, *frag_face, *frag_coord[4];

        /* For vertex shaders, keep track of the system values sources */
        struct ir3_instruction *vertex_id, *basevertex, *instance_id;

        /* mapping from nir_register to defining instruction: */
        struct hash_table *def_ht;

        unsigned num_arrays;

        /* a common pattern for indirect addressing is to request the
         * same address register multiple times.  To avoid generating
         * duplicate instruction sequences (which our backend does not
         * try to clean up, since that should be done as the NIR stage)
         * we cache the address value generated for a given src value:
         */
        struct hash_table *addr_ht;

        /* maps nir_block to ir3_block, mostly for the purposes of
         * figuring out the blocks successors
         */
        struct hash_table *block_ht;

        /* a4xx (at least patchlevel 0) cannot seem to flat-interpolate
         * so we need to use ldlv.u32 to load the varying directly:
         */
        bool flat_bypass;

        /* on a3xx, we need to add one to # of array levels:
         */
        bool levels_add_one;

        /* on a3xx, we need to scale up integer coords for isaml based
         * on LoD:
         */
        bool unminify_coords;

        /* on a4xx, for array textures we need to add 0.5 to the array
         * index coordinate:
         */
        bool array_index_add_half;

        /* for looking up which system value is which */
        unsigned sysval_semantics[8];

        /* set if we encounter something we can't handle yet, so we
         * can bail cleanly and fallback to TGSI compiler f/e
         */
        bool error;
};


static struct ir3_instruction * create_immed(struct ir3_block *block, uint32_t val);
static struct ir3_block * get_block(struct ir3_compile *ctx, nir_block *nblock);


static struct ir3_compile *
compile_init(struct ir3_compiler *compiler,
                struct ir3_shader_variant *so)
{
        struct ir3_compile *ctx = rzalloc(NULL, struct ir3_compile);

        if (compiler->gpu_id >= 400) {
                /* need special handling for "flat" */
                ctx->flat_bypass = true;
                ctx->levels_add_one = false;
                ctx->unminify_coords = false;
                ctx->array_index_add_half = true;
        } else {
                /* no special handling for "flat" */
                ctx->flat_bypass = false;
                ctx->levels_add_one = true;
                ctx->unminify_coords = true;
                ctx->array_index_add_half = false;
        }

        ctx->compiler = compiler;
        ctx->ir = so->ir;
        ctx->so = so;
        ctx->def_ht = _mesa_hash_table_create(ctx,
                        _mesa_hash_pointer, _mesa_key_pointer_equal);
        ctx->block_ht = _mesa_hash_table_create(ctx,
                        _mesa_hash_pointer, _mesa_key_pointer_equal);

        /* TODO: maybe generate some sort of bitmask of what key
         * lowers vs what shader has (ie. no need to lower
         * texture clamp lowering if no texture sample instrs)..
         * although should be done further up the stack to avoid
         * creating duplicate variants..
         */

        if (ir3_key_lowers_nir(&so->key)) {
                nir_shader *s = nir_shader_clone(ctx, so->shader->nir);
                ctx->s = ir3_optimize_nir(so->shader, s, &so->key);
        } else {
                /* fast-path for shader key that lowers nothing in NIR: */
                ctx->s = so->shader->nir;
        }

        if (fd_mesa_debug & FD_DBG_DISASM) {
                DBG("dump nir%dv%d: type=%d, k={bp=%u,cts=%u,hp=%u}",
                        so->shader->id, so->id, so->type,
                        so->key.binning_pass, so->key.color_two_side,
                        so->key.half_precision);
                nir_print_shader(ctx->s, stdout);
        }

        so->first_driver_param = so->first_immediate = ctx->s->num_uniforms;

        /* Layout of constant registers:
         *
         *    num_uniform * vec4  -  user consts
         *    4 * vec4            -  UBO addresses
         *    if (vertex shader) {
         *        N * vec4        -  driver params (IR3_DP_*)
         *        1 * vec4        -  stream-out addresses
         *    }
         *
         * TODO this could be made more dynamic, to at least skip sections
         * that we don't need..
         */

        /* reserve 4 (vec4) slots for ubo base addresses: */
        so->first_immediate += 4;

        if (so->type == SHADER_VERTEX) {
                /* driver params (see ir3_driver_param): */
                so->first_immediate += IR3_DP_COUNT/4;  /* convert to vec4 */
                /* one (vec4) slot for stream-output base addresses: */
                so->first_immediate++;
        }

        return ctx;
}

static void
compile_error(struct ir3_compile *ctx, const char *format, ...)
{
        va_list ap;
        va_start(ap, format);
        _debug_vprintf(format, ap);
        va_end(ap);
        nir_print_shader(ctx->s, stdout);
        ctx->error = true;
        debug_assert(0);
}

#define compile_assert(ctx, cond) do { \
                if (!(cond)) compile_error((ctx), "failed assert: "#cond"\n"); \
        } while (0)

static void
compile_free(struct ir3_compile *ctx)
{
        ralloc_free(ctx);
}

static void
declare_var(struct ir3_compile *ctx, nir_variable *var)
{
        unsigned length = glsl_get_length(var->type) * 4;  /* always vec4, at least with ttn */
        struct ir3_array *arr = ralloc(ctx, struct ir3_array);
        arr->id = ++ctx->num_arrays;
        arr->length = length;
        arr->var = var;
        list_addtail(&arr->node, &ctx->ir->array_list);
}

static struct ir3_array *
get_var(struct ir3_compile *ctx, nir_variable *var)
{
        list_for_each_entry (struct ir3_array, arr, &ctx->ir->array_list, node) {
                if (arr->var == var)
                        return arr;
        }
        compile_error(ctx, "bogus var: %s\n", var->name);
        return NULL;
}

/* allocate a n element value array (to be populated by caller) and
 * insert in def_ht
 */
static struct ir3_instruction **
__get_dst(struct ir3_compile *ctx, void *key, unsigned n)
{
        struct ir3_instruction **value =
                ralloc_array(ctx->def_ht, struct ir3_instruction *, n);
        _mesa_hash_table_insert(ctx->def_ht, key, value);
        return value;
}

static struct ir3_instruction **
get_dst(struct ir3_compile *ctx, nir_dest *dst, unsigned n)
{
        compile_assert(ctx, dst->is_ssa);
        if (dst->is_ssa) {
                return __get_dst(ctx, &dst->ssa, n);
        } else {
                return __get_dst(ctx, dst->reg.reg, n);
        }
}

static struct ir3_instruction **
get_dst_ssa(struct ir3_compile *ctx, nir_ssa_def *dst, unsigned n)
{
        return __get_dst(ctx, dst, n);
}

static struct ir3_instruction **
get_src(struct ir3_compile *ctx, nir_src *src)
{
        struct hash_entry *entry;
        compile_assert(ctx, src->is_ssa);
        if (src->is_ssa) {
                entry = _mesa_hash_table_search(ctx->def_ht, src->ssa);
        } else {
                entry = _mesa_hash_table_search(ctx->def_ht, src->reg.reg);
        }
        compile_assert(ctx, entry);
        return entry->data;
}

static struct ir3_instruction *
create_immed(struct ir3_block *block, uint32_t val)
{
        struct ir3_instruction *mov;

        mov = ir3_instr_create(block, OPC_MOV);
        mov->cat1.src_type = TYPE_U32;
        mov->cat1.dst_type = TYPE_U32;
        ir3_reg_create(mov, 0, 0);
        ir3_reg_create(mov, 0, IR3_REG_IMMED)->uim_val = val;

        return mov;
}

static struct ir3_instruction *
create_addr(struct ir3_block *block, struct ir3_instruction *src)
{
        struct ir3_instruction *instr, *immed;

        /* TODO in at least some cases, the backend could probably be
         * made clever enough to propagate IR3_REG_HALF..
         */
        instr = ir3_COV(block, src, TYPE_U32, TYPE_S16);
        instr->regs[0]->flags |= IR3_REG_HALF;

        immed = create_immed(block, 2);
        immed->regs[0]->flags |= IR3_REG_HALF;

        instr = ir3_SHL_B(block, instr, 0, immed, 0);
        instr->regs[0]->flags |= IR3_REG_HALF;
        instr->regs[1]->flags |= IR3_REG_HALF;

        instr = ir3_MOV(block, instr, TYPE_S16);
        instr->regs[0]->num = regid(REG_A0, 0);
        instr->regs[0]->flags |= IR3_REG_HALF;
        instr->regs[1]->flags |= IR3_REG_HALF;

        return instr;
}

/* caches addr values to avoid generating multiple cov/shl/mova
 * sequences for each use of a given NIR level src as address
 */
static struct ir3_instruction *
get_addr(struct ir3_compile *ctx, struct ir3_instruction *src)
{
        struct ir3_instruction *addr;

        if (!ctx->addr_ht) {
                ctx->addr_ht = _mesa_hash_table_create(ctx,
                                _mesa_hash_pointer, _mesa_key_pointer_equal);
        } else {
                struct hash_entry *entry;
                entry = _mesa_hash_table_search(ctx->addr_ht, src);
                if (entry)
                        return entry->data;
        }

        addr = create_addr(ctx->block, src);
        _mesa_hash_table_insert(ctx->addr_ht, src, addr);

        return addr;
}

static struct ir3_instruction *
get_predicate(struct ir3_compile *ctx, struct ir3_instruction *src)
{
        struct ir3_block *b = ctx->block;
        struct ir3_instruction *cond;

        /* NOTE: only cmps.*.* can write p0.x: */
        cond = ir3_CMPS_S(b, src, 0, create_immed(b, 0), 0);
        cond->cat2.condition = IR3_COND_NE;

        /* condition always goes in predicate register: */
        cond->regs[0]->num = regid(REG_P0, 0);

        return cond;
}

static struct ir3_instruction *
create_uniform(struct ir3_compile *ctx, unsigned n)
{
        struct ir3_instruction *mov;

        mov = ir3_instr_create(ctx->block, OPC_MOV);
        /* TODO get types right? */
        mov->cat1.src_type = TYPE_F32;
        mov->cat1.dst_type = TYPE_F32;
        ir3_reg_create(mov, 0, 0);
        ir3_reg_create(mov, n, IR3_REG_CONST);

        return mov;
}

static struct ir3_instruction *
create_uniform_indirect(struct ir3_compile *ctx, int n,
                struct ir3_instruction *address)
{
        struct ir3_instruction *mov;

        mov = ir3_instr_create(ctx->block, OPC_MOV);
        mov->cat1.src_type = TYPE_U32;
        mov->cat1.dst_type = TYPE_U32;
        ir3_reg_create(mov, 0, 0);
        ir3_reg_create(mov, 0, IR3_REG_CONST | IR3_REG_RELATIV)->array.offset = n;

        ir3_instr_set_address(mov, address);

        return mov;
}

static struct ir3_instruction *
create_collect(struct ir3_block *block, struct ir3_instruction **arr,
                unsigned arrsz)
{
        struct ir3_instruction *collect;

        if (arrsz == 0)
                return NULL;

        collect = ir3_instr_create2(block, OPC_META_FI, 1 + arrsz);
        ir3_reg_create(collect, 0, 0);     /* dst */
        for (unsigned i = 0; i < arrsz; i++)
                ir3_reg_create(collect, 0, IR3_REG_SSA)->instr = arr[i];

        return collect;
}

static struct ir3_instruction *
create_indirect_load(struct ir3_compile *ctx, unsigned arrsz, int n,
                struct ir3_instruction *address, struct ir3_instruction *collect)
{
        struct ir3_block *block = ctx->block;
        struct ir3_instruction *mov;
        struct ir3_register *src;

        mov = ir3_instr_create(block, OPC_MOV);
        mov->cat1.src_type = TYPE_U32;
        mov->cat1.dst_type = TYPE_U32;
        ir3_reg_create(mov, 0, 0);
        src = ir3_reg_create(mov, 0, IR3_REG_SSA | IR3_REG_RELATIV);
        src->instr = collect;
        src->size  = arrsz;
        src->array.offset = n;

        ir3_instr_set_address(mov, address);

        return mov;
}

/* relative (indirect) if address!=NULL */
static struct ir3_instruction *
create_var_load(struct ir3_compile *ctx, struct ir3_array *arr, int n,
                struct ir3_instruction *address)
{
        struct ir3_block *block = ctx->block;
        struct ir3_instruction *mov;
        struct ir3_register *src;

        mov = ir3_instr_create(block, OPC_MOV);
        mov->cat1.src_type = TYPE_U32;
        mov->cat1.dst_type = TYPE_U32;
        ir3_reg_create(mov, 0, 0);
        src = ir3_reg_create(mov, 0, IR3_REG_ARRAY |
                        COND(address, IR3_REG_RELATIV));
        src->instr = arr->last_write;
        src->size  = arr->length;
        src->array.id = arr->id;
        src->array.offset = n;

        if (address)
                ir3_instr_set_address(mov, address);

        arr->last_access = mov;

        return mov;
}

/* relative (indirect) if address!=NULL */
static struct ir3_instruction *
create_var_store(struct ir3_compile *ctx, struct ir3_array *arr, int n,
                struct ir3_instruction *src, struct ir3_instruction *address)
{
        struct ir3_block *block = ctx->block;
        struct ir3_instruction *mov;
        struct ir3_register *dst;

        mov = ir3_instr_create(block, OPC_MOV);
        mov->cat1.src_type = TYPE_U32;
        mov->cat1.dst_type = TYPE_U32;
        dst = ir3_reg_create(mov, 0, IR3_REG_ARRAY |
                        COND(address, IR3_REG_RELATIV));
        dst->instr = arr->last_access;
        dst->size  = arr->length;
        dst->array.id = arr->id;
        dst->array.offset = n;
        ir3_reg_create(mov, 0, IR3_REG_SSA)->instr = src;

        ir3_instr_set_address(mov, address);

        arr->last_write = arr->last_access = mov;

        return mov;
}

static struct ir3_instruction *
create_input(struct ir3_block *block, unsigned n)
{
        struct ir3_instruction *in;

        in = ir3_instr_create(block, OPC_META_INPUT);
        in->inout.block = block;
        ir3_reg_create(in, n, 0);

        return in;
}

static struct ir3_instruction *
create_frag_input(struct ir3_compile *ctx, bool use_ldlv)
{
        struct ir3_block *block = ctx->block;
        struct ir3_instruction *instr;
        /* actual inloc is assigned and fixed up later: */
        struct ir3_instruction *inloc = create_immed(block, 0);

        if (use_ldlv) {
                instr = ir3_LDLV(block, inloc, 0, create_immed(block, 1), 0);
                instr->cat6.type = TYPE_U32;
                instr->cat6.iim_val = 1;
        } else {
                instr = ir3_BARY_F(block, inloc, 0, ctx->frag_pos, 0);
                instr->regs[2]->wrmask = 0x3;
        }

        return instr;
}

static struct ir3_instruction *
create_frag_coord(struct ir3_compile *ctx, unsigned comp)
{
        struct ir3_block *block = ctx->block;
        struct ir3_instruction *instr;

        compile_assert(ctx, !ctx->frag_coord[comp]);

        ctx->frag_coord[comp] = create_input(ctx->block, 0);

        switch (comp) {
        case 0: /* .x */
        case 1: /* .y */
                /* for frag_coord, we get unsigned values.. we need
                 * to subtract (integer) 8 and divide by 16 (right-
                 * shift by 4) then convert to float:
                 *
                 *    sub.s tmp, src, 8
                 *    shr.b tmp, tmp, 4
                 *    mov.u32f32 dst, tmp
                 *
                 */
                instr = ir3_SUB_S(block, ctx->frag_coord[comp], 0,
                                create_immed(block, 8), 0);
                instr = ir3_SHR_B(block, instr, 0,
                                create_immed(block, 4), 0);
                instr = ir3_COV(block, instr, TYPE_U32, TYPE_F32);

                return instr;
        case 2: /* .z */
        case 3: /* .w */
        default:
                /* seems that we can use these as-is: */
                return ctx->frag_coord[comp];
        }
}

/* NOTE: this creates the "TGSI" style fragface (ie. input slot
 * VARYING_SLOT_FACE).  For NIR style nir_intrinsic_load_front_face
 * we can just use the value from hw directly (since it is boolean)
 */
static struct ir3_instruction *
create_frag_face(struct ir3_compile *ctx, unsigned comp)
{
        struct ir3_block *block = ctx->block;
        struct ir3_instruction *instr;

        switch (comp) {
        case 0: /* .x */
                compile_assert(ctx, !ctx->frag_face);

                ctx->frag_face = create_input(block, 0);
                ctx->frag_face->regs[0]->flags |= IR3_REG_HALF;

                /* for faceness, we always get -1 or 0 (int).. but TGSI expects
                 * positive vs negative float.. and piglit further seems to
                 * expect -1.0 or 1.0:
                 *
                 *    mul.s tmp, hr0.x, 2
                 *    add.s tmp, tmp, 1
                 *    mov.s32f32, dst, tmp
                 *
                 */
                instr = ir3_MUL_S(block, ctx->frag_face, 0,
                                create_immed(block, 2), 0);
                instr = ir3_ADD_S(block, instr, 0,
                                create_immed(block, 1), 0);
                instr = ir3_COV(block, instr, TYPE_S32, TYPE_F32);

                return instr;
        case 1: /* .y */
        case 2: /* .z */
                return create_immed(block, fui(0.0));
        default:
        case 3: /* .w */
                return create_immed(block, fui(1.0));
        }
}

static struct ir3_instruction *
create_driver_param(struct ir3_compile *ctx, enum ir3_driver_param dp)
{
        /* first four vec4 sysval's reserved for UBOs: */
        /* NOTE: dp is in scalar, but there can be >4 dp components: */
        unsigned n = ctx->so->first_driver_param + IR3_DRIVER_PARAM_OFF;
        unsigned r = regid(n + dp / 4, dp % 4);
        return create_uniform(ctx, r);
}

/* helper for instructions that produce multiple consecutive scalar
 * outputs which need to have a split/fanout meta instruction inserted
 */
static void
split_dest(struct ir3_block *block, struct ir3_instruction **dst,
                struct ir3_instruction *src, unsigned n)
{
        struct ir3_instruction *prev = NULL;
        for (int i = 0, j = 0; i < n; i++) {
                struct ir3_instruction *split = ir3_instr_create(block, OPC_META_FO);
                ir3_reg_create(split, 0, IR3_REG_SSA);
                ir3_reg_create(split, 0, IR3_REG_SSA)->instr = src;
                split->fo.off = i;

                if (prev) {
                        split->cp.left = prev;
                        split->cp.left_cnt++;
                        prev->cp.right = split;
                        prev->cp.right_cnt++;
                }
                prev = split;

                if (src->regs[0]->wrmask & (1 << i))
                        dst[j++] = split;
        }
}

/*
 * Adreno uses uint rather than having dedicated bool type,
 * which (potentially) requires some conversion, in particular
 * when using output of an bool instr to int input, or visa
 * versa.
 *
 *         | Adreno  |  NIR  |
 *  -------+---------+-------+-
 *   true  |    1    |  ~0   |
 *   false |    0    |   0   |
 *
 * To convert from an adreno bool (uint) to nir, use:
 *
 *    absneg.s dst, (neg)src
 *
 * To convert back in the other direction:
 *
 *    absneg.s dst, (abs)arc
 *
 * The CP step can clean up the absneg.s that cancel each other
 * out, and with a slight bit of extra cleverness (to recognize
 * the instructions which produce either a 0 or 1) can eliminate
 * the absneg.s's completely when an instruction that wants
 * 0/1 consumes the result.  For example, when a nir 'bcsel'
 * consumes the result of 'feq'.  So we should be able to get by
 * without a boolean resolve step, and without incuring any
 * extra penalty in instruction count.
 */

/* NIR bool -> native (adreno): */
static struct ir3_instruction *
ir3_b2n(struct ir3_block *block, struct ir3_instruction *instr)
{
        return ir3_ABSNEG_S(block, instr, IR3_REG_SABS);
}

/* native (adreno) -> NIR bool: */
static struct ir3_instruction *
ir3_n2b(struct ir3_block *block, struct ir3_instruction *instr)
{
        return ir3_ABSNEG_S(block, instr, IR3_REG_SNEG);
}

/*
 * alu/sfu instructions:
 */

static void
emit_alu(struct ir3_compile *ctx, nir_alu_instr *alu)
{
        const nir_op_info *info = &nir_op_infos[alu->op];
        struct ir3_instruction **dst, *src[info->num_inputs];
        struct ir3_block *b = ctx->block;

        dst = get_dst(ctx, &alu->dest.dest, MAX2(info->output_size, 1));

        /* Vectors are special in that they have non-scalarized writemasks,
         * and just take the first swizzle channel for each argument in
         * order into each writemask channel.
         */
        if ((alu->op == nir_op_vec2) ||
                        (alu->op == nir_op_vec3) ||
                        (alu->op == nir_op_vec4)) {

                for (int i = 0; i < info->num_inputs; i++) {
                        nir_alu_src *asrc = &alu->src[i];

                        compile_assert(ctx, !asrc->abs);
                        compile_assert(ctx, !asrc->negate);

                        src[i] = get_src(ctx, &asrc->src)[asrc->swizzle[0]];
                        if (!src[i])
                                src[i] = create_immed(ctx->block, 0);
                        dst[i] = ir3_MOV(b, src[i], TYPE_U32);
                }

                return;
        }

        /* General case: We can just grab the one used channel per src. */
        for (int i = 0; i < info->num_inputs; i++) {
                unsigned chan = ffs(alu->dest.write_mask) - 1;
                nir_alu_src *asrc = &alu->src[i];

                compile_assert(ctx, !asrc->abs);
                compile_assert(ctx, !asrc->negate);

                src[i] = get_src(ctx, &asrc->src)[asrc->swizzle[chan]];

                compile_assert(ctx, src[i]);
        }

        switch (alu->op) {
        case nir_op_f2i:
                dst[0] = ir3_COV(b, src[0], TYPE_F32, TYPE_S32);
                break;
        case nir_op_f2u:
                dst[0] = ir3_COV(b, src[0], TYPE_F32, TYPE_U32);
                break;
        case nir_op_i2f:
                dst[0] = ir3_COV(b, src[0], TYPE_S32, TYPE_F32);
                break;
        case nir_op_u2f:
                dst[0] = ir3_COV(b, src[0], TYPE_U32, TYPE_F32);
                break;
        case nir_op_imov:
                dst[0] = ir3_MOV(b, src[0], TYPE_S32);
                break;
        case nir_op_fmov:
                dst[0] = ir3_MOV(b, src[0], TYPE_F32);
                break;
        case nir_op_f2b:
                dst[0] = ir3_CMPS_F(b, src[0], 0, create_immed(b, fui(0.0)), 0);
                dst[0]->cat2.condition = IR3_COND_NE;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_b2f:
                dst[0] = ir3_COV(b, ir3_b2n(b, src[0]), TYPE_U32, TYPE_F32);
                break;
        case nir_op_b2i:
                dst[0] = ir3_b2n(b, src[0]);
                break;
        case nir_op_i2b:
                dst[0] = ir3_CMPS_S(b, src[0], 0, create_immed(b, 0), 0);
                dst[0]->cat2.condition = IR3_COND_NE;
                dst[0] = ir3_n2b(b, dst[0]);
                break;

        case nir_op_fneg:
                dst[0] = ir3_ABSNEG_F(b, src[0], IR3_REG_FNEG);
                break;
        case nir_op_fabs:
                dst[0] = ir3_ABSNEG_F(b, src[0], IR3_REG_FABS);
                break;
        case nir_op_fmax:
                dst[0] = ir3_MAX_F(b, src[0], 0, src[1], 0);
                break;
        case nir_op_fmin:
                dst[0] = ir3_MIN_F(b, src[0], 0, src[1], 0);
                break;
        case nir_op_fmul:
                dst[0] = ir3_MUL_F(b, src[0], 0, src[1], 0);
                break;
        case nir_op_fadd:
                dst[0] = ir3_ADD_F(b, src[0], 0, src[1], 0);
                break;
        case nir_op_fsub:
                dst[0] = ir3_ADD_F(b, src[0], 0, src[1], IR3_REG_FNEG);
                break;
        case nir_op_ffma:
                dst[0] = ir3_MAD_F32(b, src[0], 0, src[1], 0, src[2], 0);
                break;
        case nir_op_fddx:
                dst[0] = ir3_DSX(b, src[0], 0);
                dst[0]->cat5.type = TYPE_F32;
                break;
        case nir_op_fddy:
                dst[0] = ir3_DSY(b, src[0], 0);
                dst[0]->cat5.type = TYPE_F32;
                break;
                break;
        case nir_op_flt:
                dst[0] = ir3_CMPS_F(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_LT;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_fge:
                dst[0] = ir3_CMPS_F(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_GE;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_feq:
                dst[0] = ir3_CMPS_F(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_EQ;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_fne:
                dst[0] = ir3_CMPS_F(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_NE;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_fceil:
                dst[0] = ir3_CEIL_F(b, src[0], 0);
                break;
        case nir_op_ffloor:
                dst[0] = ir3_FLOOR_F(b, src[0], 0);
                break;
        case nir_op_ftrunc:
                dst[0] = ir3_TRUNC_F(b, src[0], 0);
                break;
        case nir_op_fround_even:
                dst[0] = ir3_RNDNE_F(b, src[0], 0);
                break;
        case nir_op_fsign:
                dst[0] = ir3_SIGN_F(b, src[0], 0);
                break;

        case nir_op_fsin:
                dst[0] = ir3_SIN(b, src[0], 0);
                break;
        case nir_op_fcos:
                dst[0] = ir3_COS(b, src[0], 0);
                break;
        case nir_op_frsq:
                dst[0] = ir3_RSQ(b, src[0], 0);
                break;
        case nir_op_frcp:
                dst[0] = ir3_RCP(b, src[0], 0);
                break;
        case nir_op_flog2:
                dst[0] = ir3_LOG2(b, src[0], 0);
                break;
        case nir_op_fexp2:
                dst[0] = ir3_EXP2(b, src[0], 0);
                break;
        case nir_op_fsqrt:
                dst[0] = ir3_SQRT(b, src[0], 0);
                break;

        case nir_op_iabs:
                dst[0] = ir3_ABSNEG_S(b, src[0], IR3_REG_SABS);
                break;
        case nir_op_iadd:
                dst[0] = ir3_ADD_U(b, src[0], 0, src[1], 0);
                break;
        case nir_op_iand:
                dst[0] = ir3_AND_B(b, src[0], 0, src[1], 0);
                break;
        case nir_op_imax:
                dst[0] = ir3_MAX_S(b, src[0], 0, src[1], 0);
                break;
        case nir_op_umax:
                dst[0] = ir3_MAX_U(b, src[0], 0, src[1], 0);
                break;
        case nir_op_imin:
                dst[0] = ir3_MIN_S(b, src[0], 0, src[1], 0);
                break;
        case nir_op_umin:
                dst[0] = ir3_MIN_U(b, src[0], 0, src[1], 0);
                break;
        case nir_op_imul:
                /*
                 * dst = (al * bl) + (ah * bl << 16) + (al * bh << 16)
                 *   mull.u tmp0, a, b           ; mul low, i.e. al * bl
                 *   madsh.m16 tmp1, a, b, tmp0  ; mul-add shift high mix, i.e. ah * bl << 16
                 *   madsh.m16 dst, b, a, tmp1   ; i.e. al * bh << 16
                 */
                dst[0] = ir3_MADSH_M16(b, src[1], 0, src[0], 0,
                                        ir3_MADSH_M16(b, src[0], 0, src[1], 0,
                                                ir3_MULL_U(b, src[0], 0, src[1], 0), 0), 0);
                break;
        case nir_op_ineg:
                dst[0] = ir3_ABSNEG_S(b, src[0], IR3_REG_SNEG);
                break;
        case nir_op_inot:
                dst[0] = ir3_NOT_B(b, src[0], 0);
                break;
        case nir_op_ior:
                dst[0] = ir3_OR_B(b, src[0], 0, src[1], 0);
                break;
        case nir_op_ishl:
                dst[0] = ir3_SHL_B(b, src[0], 0, src[1], 0);
                break;
        case nir_op_ishr:
                dst[0] = ir3_ASHR_B(b, src[0], 0, src[1], 0);
                break;
        case nir_op_isign: {
                /* maybe this would be sane to lower in nir.. */
                struct ir3_instruction *neg, *pos;

                neg = ir3_CMPS_S(b, src[0], 0, create_immed(b, 0), 0);
                neg->cat2.condition = IR3_COND_LT;

                pos = ir3_CMPS_S(b, src[0], 0, create_immed(b, 0), 0);
                pos->cat2.condition = IR3_COND_GT;

                dst[0] = ir3_SUB_U(b, pos, 0, neg, 0);

                break;
        }
        case nir_op_isub:
                dst[0] = ir3_SUB_U(b, src[0], 0, src[1], 0);
                break;
        case nir_op_ixor:
                dst[0] = ir3_XOR_B(b, src[0], 0, src[1], 0);
                break;
        case nir_op_ushr:
                dst[0] = ir3_SHR_B(b, src[0], 0, src[1], 0);
                break;
        case nir_op_ilt:
                dst[0] = ir3_CMPS_S(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_LT;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_ige:
                dst[0] = ir3_CMPS_S(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_GE;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_ieq:
                dst[0] = ir3_CMPS_S(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_EQ;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_ine:
                dst[0] = ir3_CMPS_S(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_NE;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_ult:
                dst[0] = ir3_CMPS_U(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_LT;
                dst[0] = ir3_n2b(b, dst[0]);
                break;
        case nir_op_uge:
                dst[0] = ir3_CMPS_U(b, src[0], 0, src[1], 0);
                dst[0]->cat2.condition = IR3_COND_GE;
                dst[0] = ir3_n2b(b, dst[0]);
                break;

        case nir_op_bcsel:
                dst[0] = ir3_SEL_B32(b, src[1], 0, ir3_b2n(b, src[0]), 0, src[2], 0);
                break;

        case nir_op_bit_count:
                dst[0] = ir3_CBITS_B(b, src[0], 0);
                break;
        case nir_op_ifind_msb: {
                struct ir3_instruction *cmp;
                dst[0] = ir3_CLZ_S(b, src[0], 0);
                cmp = ir3_CMPS_S(b, dst[0], 0, create_immed(b, 0), 0);
                cmp->cat2.condition = IR3_COND_GE;
                dst[0] = ir3_SEL_B32(b,
                                ir3_SUB_U(b, create_immed(b, 31), 0, dst[0], 0), 0,
                                cmp, 0, dst[0], 0);
                break;
        }
        case nir_op_ufind_msb:
                dst[0] = ir3_CLZ_B(b, src[0], 0);
                dst[0] = ir3_SEL_B32(b,
                                ir3_SUB_U(b, create_immed(b, 31), 0, dst[0], 0), 0,
                                src[0], 0, dst[0], 0);
                break;
        case nir_op_find_lsb:
                dst[0] = ir3_BFREV_B(b, src[0], 0);
                dst[0] = ir3_CLZ_B(b, dst[0], 0);
                break;
        case nir_op_bitfield_reverse:
                dst[0] = ir3_BFREV_B(b, src[0], 0);
                break;

        default:
                compile_error(ctx, "Unhandled ALU op: %s\n",
                                nir_op_infos[alu->op].name);
                break;
        }
}

/* handles direct/indirect UBO reads: */
static void
emit_intrinsic_load_ubo(struct ir3_compile *ctx, nir_intrinsic_instr *intr,
                struct ir3_instruction **dst)
{
        struct ir3_block *b = ctx->block;
        struct ir3_instruction *addr, *src0, *src1;
        nir_const_value *const_offset;
        /* UBO addresses are the first driver params: */
        unsigned ubo = regid(ctx->so->first_driver_param + IR3_UBOS_OFF, 0);
        int off = 0;

        /* First src is ubo index, which could either be an immed or not: */
        src0 = get_src(ctx, &intr->src[0])[0];
        if (is_same_type_mov(src0) &&
                        (src0->regs[1]->flags & IR3_REG_IMMED)) {
                addr = create_uniform(ctx, ubo + src0->regs[1]->iim_val);
        } else {
                addr = create_uniform_indirect(ctx, ubo, get_addr(ctx, src0));
        }

        const_offset = nir_src_as_const_value(intr->src[1]);
        if (const_offset) {
                off += const_offset->u32[0];
        } else {
                /* For load_ubo_indirect, second src is indirect offset: */
                src1 = get_src(ctx, &intr->src[1])[0];

                /* and add offset to addr: */
                addr = ir3_ADD_S(b, addr, 0, src1, 0);
        }

        /* if offset is to large to encode in the ldg, split it out: */
        if ((off + (intr->num_components * 4)) > 1024) {
                /* split out the minimal amount to improve the odds that
                 * cp can fit the immediate in the add.s instruction:
                 */
                unsigned off2 = off + (intr->num_components * 4) - 1024;
                addr = ir3_ADD_S(b, addr, 0, create_immed(b, off2), 0);
                off -= off2;
        }

        for (int i = 0; i < intr->num_components; i++) {
                struct ir3_instruction *load =
                                ir3_LDG(b, addr, 0, create_immed(b, 1), 0);
                load->cat6.type = TYPE_U32;
                load->cat6.src_offset = off + i * 4;     /* byte offset */
                dst[i] = load;
        }
}

/* handles array reads: */
static void
emit_intrinsic_load_var(struct ir3_compile *ctx, nir_intrinsic_instr *intr,
                struct ir3_instruction **dst)
{
        nir_deref_var *dvar = intr->variables[0];
        nir_deref_array *darr = nir_deref_as_array(dvar->deref.child);
        struct ir3_array *arr = get_var(ctx, dvar->var);

        compile_assert(ctx, dvar->deref.child &&
                (dvar->deref.child->deref_type == nir_deref_type_array));

        switch (darr->deref_array_type) {
        case nir_deref_array_type_direct:
                /* direct access does not require anything special: */
                for (int i = 0; i < intr->num_components; i++) {
                        unsigned n = darr->base_offset * 4 + i;
                        compile_assert(ctx, n < arr->length);
                        dst[i] = create_var_load(ctx, arr, n, NULL);
                }
                break;
        case nir_deref_array_type_indirect: {
                /* for indirect, we need to collect all the array elements: */
                struct ir3_instruction *addr =
                                get_addr(ctx, get_src(ctx, &darr->indirect)[0]);
                for (int i = 0; i < intr->num_components; i++) {
                        unsigned n = darr->base_offset * 4 + i;
                        compile_assert(ctx, n < arr->length);
                        dst[i] = create_var_load(ctx, arr, n, addr);
                }
                break;
        }
        default:
                compile_error(ctx, "Unhandled load deref type: %u\n",
                                darr->deref_array_type);
                break;
        }
}

/* handles array writes: */
static void
emit_intrinsic_store_var(struct ir3_compile *ctx, nir_intrinsic_instr *intr)
{
        nir_deref_var *dvar = intr->variables[0];
        nir_deref_array *darr = nir_deref_as_array(dvar->deref.child);
        struct ir3_array *arr = get_var(ctx, dvar->var);
        struct ir3_instruction *addr, **src;
        unsigned wrmask = nir_intrinsic_write_mask(intr);

        compile_assert(ctx, dvar->deref.child &&
                (dvar->deref.child->deref_type == nir_deref_type_array));

        src = get_src(ctx, &intr->src[0]);

        switch (darr->deref_array_type) {
        case nir_deref_array_type_direct:
                addr = NULL;
                break;
        case nir_deref_array_type_indirect:
                addr = get_addr(ctx, get_src(ctx, &darr->indirect)[0]);
                break;
        default:
                compile_error(ctx, "Unhandled store deref type: %u\n",
                                darr->deref_array_type);
                return;
        }

        for (int i = 0; i < intr->num_components; i++) {
                if (!(wrmask & (1 << i)))
                        continue;
                unsigned n = darr->base_offset * 4 + i;
                compile_assert(ctx, n < arr->length);
                create_var_store(ctx, arr, n, src[i], addr);
        }
}

static void add_sysval_input(struct ir3_compile *ctx, gl_system_value slot,
                struct ir3_instruction *instr)
{
        struct ir3_shader_variant *so = ctx->so;
        unsigned r = regid(so->inputs_count, 0);
        unsigned n = so->inputs_count++;

        so->inputs[n].sysval = true;
        so->inputs[n].slot = slot;
        so->inputs[n].compmask = 1;
        so->inputs[n].regid = r;
        so->inputs[n].interpolate = INTERP_QUALIFIER_FLAT;
        so->total_in++;

        ctx->ir->ninputs = MAX2(ctx->ir->ninputs, r + 1);
        ctx->ir->inputs[r] = instr;
}

static void
emit_intrinsic(struct ir3_compile *ctx, nir_intrinsic_instr *intr)
{
        const nir_intrinsic_info *info = &nir_intrinsic_infos[intr->intrinsic];
        struct ir3_instruction **dst, **src;
        struct ir3_block *b = ctx->block;
        nir_const_value *const_offset;
        int idx;

        if (info->has_dest) {
                dst = get_dst(ctx, &intr->dest, intr->num_components);
        } else {
                dst = NULL;
        }

        switch (intr->intrinsic) {
        case nir_intrinsic_load_uniform:
                idx = nir_intrinsic_base(intr);
                const_offset = nir_src_as_const_value(intr->src[0]);
                if (const_offset) {
                        idx += const_offset->u32[0];
                        for (int i = 0; i < intr->num_components; i++) {
                                unsigned n = idx * 4 + i;
                                dst[i] = create_uniform(ctx, n);
                        }
                } else {
                        src = get_src(ctx, &intr->src[0]);
                        for (int i = 0; i < intr->num_components; i++) {
                                int n = idx * 4 + i;
                                dst[i] = create_uniform_indirect(ctx, n,
                                                get_addr(ctx, src[0]));
                        }
                        /* NOTE: if relative addressing is used, we set
                         * constlen in the compiler (to worst-case value)
                         * since we don't know in the assembler what the max
                         * addr reg value can be:
                         */
                        ctx->so->constlen = ctx->s->num_uniforms;
                }
                break;
        case nir_intrinsic_load_ubo:
                emit_intrinsic_load_ubo(ctx, intr, dst);
                break;
        case nir_intrinsic_load_input:
                idx = nir_intrinsic_base(intr);
                const_offset = nir_src_as_const_value(intr->src[0]);
                if (const_offset) {
                        idx += const_offset->u32[0];
                        for (int i = 0; i < intr->num_components; i++) {
                                unsigned n = idx * 4 + i;
                                dst[i] = ctx->ir->inputs[n];
                        }
                } else {
                        src = get_src(ctx, &intr->src[0]);
                        struct ir3_instruction *collect =
                                        create_collect(b, ctx->ir->inputs, ctx->ir->ninputs);
                        struct ir3_instruction *addr = get_addr(ctx, src[0]);
                        for (int i = 0; i < intr->num_components; i++) {
                                unsigned n = idx * 4 + i;
                                dst[i] = create_indirect_load(ctx, ctx->ir->ninputs,
                                                n, addr, collect);
                        }
                }
                break;
        case nir_intrinsic_load_var:
                emit_intrinsic_load_var(ctx, intr, dst);
                break;
        case nir_intrinsic_store_var:
                emit_intrinsic_store_var(ctx, intr);
                break;
        case nir_intrinsic_store_output:
                idx = nir_intrinsic_base(intr);
                const_offset = nir_src_as_const_value(intr->src[1]);
                compile_assert(ctx, const_offset != NULL);
                idx += const_offset->u32[0];

                src = get_src(ctx, &intr->src[0]);
                for (int i = 0; i < intr->num_components; i++) {
                        unsigned n = idx * 4 + i;
                        ctx->ir->outputs[n] = src[i];
                }
                break;
        case nir_intrinsic_load_base_vertex:
                if (!ctx->basevertex) {
                        ctx->basevertex = create_driver_param(ctx, IR3_DP_VTXID_BASE);
                        add_sysval_input(ctx, SYSTEM_VALUE_BASE_VERTEX,
                                        ctx->basevertex);
                }
                dst[0] = ctx->basevertex;
                break;
        case nir_intrinsic_load_vertex_id_zero_base:
                if (!ctx->vertex_id) {
                        ctx->vertex_id = create_input(b, 0);
                        add_sysval_input(ctx, SYSTEM_VALUE_VERTEX_ID_ZERO_BASE,
                                        ctx->vertex_id);
                }
                dst[0] = ctx->vertex_id;
                break;
        case nir_intrinsic_load_instance_id:
                if (!ctx->instance_id) {
                        ctx->instance_id = create_input(b, 0);
                        add_sysval_input(ctx, SYSTEM_VALUE_INSTANCE_ID,
                                        ctx->instance_id);
                }
                dst[0] = ctx->instance_id;
                break;
        case nir_intrinsic_load_user_clip_plane:
                idx = nir_intrinsic_ucp_id(intr);
                for (int i = 0; i < intr->num_components; i++) {
                        unsigned n = idx * 4 + i;
                        dst[i] = create_driver_param(ctx, IR3_DP_UCP0_X + n);
                }
                break;
        case nir_intrinsic_load_front_face:
                if (!ctx->frag_face) {
                        ctx->so->frag_face = true;
                        ctx->frag_face = create_input(b, 0);
                        ctx->frag_face->regs[0]->flags |= IR3_REG_HALF;
                }
                /* for fragface, we always get -1 or 0, but that is inverse
                 * of what nir expects (where ~0 is true).  Unfortunately
                 * trying to widen from half to full in add.s seems to do a
                 * non-sign-extending widen (resulting in something that
                 * gets interpreted as float Inf??)
                 */
                dst[0] = ir3_COV(b, ctx->frag_face, TYPE_S16, TYPE_S32);
                dst[0] = ir3_ADD_S(b, dst[0], 0, create_immed(b, 1), 0);
                break;
        case nir_intrinsic_discard_if:
        case nir_intrinsic_discard: {
                struct ir3_instruction *cond, *kill;

                if (intr->intrinsic == nir_intrinsic_discard_if) {
                        /* conditional discard: */
                        src = get_src(ctx, &intr->src[0]);
                        cond = ir3_b2n(b, src[0]);
                } else {
                        /* unconditional discard: */
                        cond = create_immed(b, 1);
                }

                /* NOTE: only cmps.*.* can write p0.x: */
                cond = ir3_CMPS_S(b, cond, 0, create_immed(b, 0), 0);
                cond->cat2.condition = IR3_COND_NE;

                /* condition always goes in predicate register: */
                cond->regs[0]->num = regid(REG_P0, 0);

                kill = ir3_KILL(b, cond, 0);
                array_insert(ctx->ir->predicates, kill);

                array_insert(ctx->ir->keeps, kill);
                ctx->so->has_kill = true;

                break;
        }
        default:
                compile_error(ctx, "Unhandled intrinsic type: %s\n",
                                nir_intrinsic_infos[intr->intrinsic].name);
                break;
        }
}

static void
emit_load_const(struct ir3_compile *ctx, nir_load_const_instr *instr)
{
        struct ir3_instruction **dst = get_dst_ssa(ctx, &instr->def,
                        instr->def.num_components);
        for (int i = 0; i < instr->def.num_components; i++)
                dst[i] = create_immed(ctx->block, instr->value.u32[i]);
}

static void
emit_undef(struct ir3_compile *ctx, nir_ssa_undef_instr *undef)
{
        struct ir3_instruction **dst = get_dst_ssa(ctx, &undef->def,
                        undef->def.num_components);
        /* backend doesn't want undefined instructions, so just plug
         * in 0.0..
         */
        for (int i = 0; i < undef->def.num_components; i++)
                dst[i] = create_immed(ctx->block, fui(0.0));
}

/*
 * texture fetch/sample instructions:
 */

static void
tex_info(nir_tex_instr *tex, unsigned *flagsp, unsigned *coordsp)
{
        unsigned coords, flags = 0;

        /* note: would use tex->coord_components.. except txs.. also,
         * since array index goes after shadow ref, we don't want to
         * count it:
         */
        switch (tex->sampler_dim) {
        case GLSL_SAMPLER_DIM_1D:
        case GLSL_SAMPLER_DIM_BUF:
                coords = 1;
                break;
        case GLSL_SAMPLER_DIM_2D:
        case GLSL_SAMPLER_DIM_RECT:
        case GLSL_SAMPLER_DIM_EXTERNAL:
        case GLSL_SAMPLER_DIM_MS:
                coords = 2;
                break;
        case GLSL_SAMPLER_DIM_3D:
        case GLSL_SAMPLER_DIM_CUBE:
                coords = 3;
                flags |= IR3_INSTR_3D;
                break;
        default:
                unreachable("bad sampler_dim");
        }

        if (tex->is_shadow && tex->op != nir_texop_lod)
                flags |= IR3_INSTR_S;

        if (tex->is_array && tex->op != nir_texop_lod)
                flags |= IR3_INSTR_A;

        *flagsp = flags;
        *coordsp = coords;
}

static void
emit_tex(struct ir3_compile *ctx, nir_tex_instr *tex)
{
        struct ir3_block *b = ctx->block;
        struct ir3_instruction **dst, *sam, *src0[12], *src1[4];
        struct ir3_instruction **coord, *lod, *compare, *proj, **off, **ddx, **ddy;
        bool has_bias = false, has_lod = false, has_proj = false, has_off = false;
        unsigned i, coords, flags;
        unsigned nsrc0 = 0, nsrc1 = 0;
        type_t type;
        opc_t opc = 0;

        coord = off = ddx = ddy = NULL;
        lod = proj = compare = NULL;

        /* TODO: might just be one component for gathers? */
        dst = get_dst(ctx, &tex->dest, 4);

        for (unsigned i = 0; i < tex->num_srcs; i++) {
                switch (tex->src[i].src_type) {
                case nir_tex_src_coord:
                        coord = get_src(ctx, &tex->src[i].src);
                        break;
                case nir_tex_src_bias:
                        lod = get_src(ctx, &tex->src[i].src)[0];
                        has_bias = true;
                        break;
                case nir_tex_src_lod:
                        lod = get_src(ctx, &tex->src[i].src)[0];
                        has_lod = true;
                        break;
                case nir_tex_src_comparitor: /* shadow comparator */
                        compare = get_src(ctx, &tex->src[i].src)[0];
                        break;
                case nir_tex_src_projector:
                        proj = get_src(ctx, &tex->src[i].src)[0];
                        has_proj = true;
                        break;
                case nir_tex_src_offset:
                        off = get_src(ctx, &tex->src[i].src);
                        has_off = true;
                        break;
                case nir_tex_src_ddx:
                        ddx = get_src(ctx, &tex->src[i].src);
                        break;
                case nir_tex_src_ddy:
                        ddy = get_src(ctx, &tex->src[i].src);
                        break;
                default:
                        compile_error(ctx, "Unhandled NIR tex src type: %d\n",
                                        tex->src[i].src_type);
                        return;
                }
        }

        switch (tex->op) {
        case nir_texop_tex:      opc = OPC_SAM;      break;
        case nir_texop_txb:      opc = OPC_SAMB;     break;
        case nir_texop_txl:      opc = OPC_SAML;     break;
        case nir_texop_txd:      opc = OPC_SAMGQ;    break;
        case nir_texop_txf:      opc = OPC_ISAML;    break;
        case nir_texop_lod:      opc = OPC_GETLOD;   break;
        case nir_texop_txf_ms:
        case nir_texop_txs:
        case nir_texop_tg4:
        case nir_texop_query_levels:
        case nir_texop_texture_samples:
        case nir_texop_samples_identical:
                compile_error(ctx, "Unhandled NIR tex type: %d\n", tex->op);
                return;
        }

        tex_info(tex, &flags, &coords);

        /* scale up integer coords for TXF based on the LOD */
        if (ctx->unminify_coords && (opc == OPC_ISAML)) {
                assert(has_lod);
                for (i = 0; i < coords; i++)
                        coord[i] = ir3_SHL_B(b, coord[i], 0, lod, 0);
        }

        /* the array coord for cube arrays needs 0.5 added to it */
        if (ctx->array_index_add_half && tex->is_array && (opc != OPC_ISAML))
                coord[coords] = ir3_ADD_F(b, coord[coords], 0, create_immed(b, fui(0.5)), 0);

        /*
         * lay out the first argument in the proper order:
         *  - actual coordinates first
         *  - shadow reference
         *  - array index
         *  - projection w
         *  - starting at offset 4, dpdx.xy, dpdy.xy
         *
         * bias/lod go into the second arg
         */

        /* insert tex coords: */
        for (i = 0; i < coords; i++)
                src0[nsrc0++] = coord[i];

        if (coords == 1) {
                /* hw doesn't do 1d, so we treat it as 2d with
                 * height of 1, and patch up the y coord.
                 * TODO: y coord should be (int)0 in some cases..
                 */
                src0[nsrc0++] = create_immed(b, fui(0.5));
        }

        if (tex->is_shadow && tex->op != nir_texop_lod)
                src0[nsrc0++] = compare;

        if (tex->is_array && tex->op != nir_texop_lod)
                src0[nsrc0++] = coord[coords];

        if (has_proj) {
                src0[nsrc0++] = proj;
                flags |= IR3_INSTR_P;
        }

        /* pad to 4, then ddx/ddy: */
        if (tex->op == nir_texop_txd) {
                while (nsrc0 < 4)
                        src0[nsrc0++] = create_immed(b, fui(0.0));
                for (i = 0; i < coords; i++)
                        src0[nsrc0++] = ddx[i];
                if (coords < 2)
                        src0[nsrc0++] = create_immed(b, fui(0.0));
                for (i = 0; i < coords; i++)
                        src0[nsrc0++] = ddy[i];
                if (coords < 2)
                        src0[nsrc0++] = create_immed(b, fui(0.0));
        }

        /*
         * second argument (if applicable):
         *  - offsets
         *  - lod
         *  - bias
         */
        if (has_off | has_lod | has_bias) {
                if (has_off) {
                        for (i = 0; i < coords; i++)
                                src1[nsrc1++] = off[i];
                        if (coords < 2)
                                src1[nsrc1++] = create_immed(b, fui(0.0));
                        flags |= IR3_INSTR_O;
                }

                if (has_lod | has_bias)
                        src1[nsrc1++] = lod;
        }

        switch (tex->dest_type) {
        case nir_type_invalid:
        case nir_type_float:
                type = TYPE_F32;
                break;
        case nir_type_int:
                type = TYPE_S32;
                break;
        case nir_type_uint:
        case nir_type_bool:
                type = TYPE_U32;
                break;
        default:
                unreachable("bad dest_type");
        }

        if (opc == OPC_GETLOD)
                type = TYPE_U32;

        sam = ir3_SAM(b, opc, type, TGSI_WRITEMASK_XYZW,
                        flags, tex->texture_index, tex->texture_index,
                        create_collect(b, src0, nsrc0),
                        create_collect(b, src1, nsrc1));

        split_dest(b, dst, sam, 4);

        /* GETLOD returns results in 4.8 fixed point */
        if (opc == OPC_GETLOD) {
                struct ir3_instruction *factor = create_immed(b, fui(1.0 / 256));

                compile_assert(ctx, tex->dest_type == nir_type_float);
                for (i = 0; i < 2; i++) {
                        dst[i] = ir3_MUL_F(b, ir3_COV(b, dst[i], TYPE_U32, TYPE_F32), 0,
                                                           factor, 0);
                }
        }
}

static void
emit_tex_query_levels(struct ir3_compile *ctx, nir_tex_instr *tex)
{
        struct ir3_block *b = ctx->block;
        struct ir3_instruction **dst, *sam;

        dst = get_dst(ctx, &tex->dest, 1);

        sam = ir3_SAM(b, OPC_GETINFO, TYPE_U32, TGSI_WRITEMASK_Z, 0,
                        tex->texture_index, tex->texture_index, NULL, NULL);

        /* even though there is only one component, since it ends
         * up in .z rather than .x, we need a split_dest()
         */
        split_dest(b, dst, sam, 3);

        /* The # of levels comes from getinfo.z. We need to add 1 to it, since
         * the value in TEX_CONST_0 is zero-based.
         */
        if (ctx->levels_add_one)
                dst[0] = ir3_ADD_U(b, dst[0], 0, create_immed(b, 1), 0);
}

static void
emit_tex_txs(struct ir3_compile *ctx, nir_tex_instr *tex)
{
        struct ir3_block *b = ctx->block;
        struct ir3_instruction **dst, *sam, *lod;
        unsigned flags, coords;

        tex_info(tex, &flags, &coords);

        /* Actually we want the number of dimensions, not coordinates. This
         * distinction only matters for cubes.
         */
        if (tex->sampler_dim == GLSL_SAMPLER_DIM_CUBE)
                coords = 2;

        dst = get_dst(ctx, &tex->dest, 4);

        compile_assert(ctx, tex->num_srcs == 1);
        compile_assert(ctx, tex->src[0].src_type == nir_tex_src_lod);

        lod = get_src(ctx, &tex->src[0].src)[0];

        sam = ir3_SAM(b, OPC_GETSIZE, TYPE_U32, TGSI_WRITEMASK_XYZW, flags,
                        tex->texture_index, tex->texture_index, lod, NULL);

        split_dest(b, dst, sam, 4);

        /* Array size actually ends up in .w rather than .z. This doesn't
         * matter for miplevel 0, but for higher mips the value in z is
         * minified whereas w stays. Also, the value in TEX_CONST_3_DEPTH is
         * returned, which means that we have to add 1 to it for arrays.
         */
        if (tex->is_array) {
                if (ctx->levels_add_one) {
                        dst[coords] = ir3_ADD_U(b, dst[3], 0, create_immed(b, 1), 0);
                } else {
                        dst[coords] = ir3_MOV(b, dst[3], TYPE_U32);
                }
        }
}

static void
emit_phi(struct ir3_compile *ctx, nir_phi_instr *nphi)
{
        struct ir3_instruction *phi, **dst;

        /* NOTE: phi's should be lowered to scalar at this point */
        compile_assert(ctx, nphi->dest.ssa.num_components == 1);

        dst = get_dst(ctx, &nphi->dest, 1);

        phi = ir3_instr_create2(ctx->block, OPC_META_PHI,
                        1 + exec_list_length(&nphi->srcs));
        ir3_reg_create(phi, 0, 0);         /* dst */
        phi->phi.nphi = nphi;

        dst[0] = phi;
}

/* phi instructions are left partially constructed.  We don't resolve
 * their srcs until the end of the block, since (eg. loops) one of
 * the phi's srcs might be defined after the phi due to back edges in
 * the CFG.
 */
static void
resolve_phis(struct ir3_compile *ctx, struct ir3_block *block)
{
        list_for_each_entry (struct ir3_instruction, instr, &block->instr_list, node) {
                nir_phi_instr *nphi;

                /* phi's only come at start of block: */
                if (instr->opc != OPC_META_PHI)
                        break;

                if (!instr->phi.nphi)
                        break;

                nphi = instr->phi.nphi;
                instr->phi.nphi = NULL;

                foreach_list_typed(nir_phi_src, nsrc, node, &nphi->srcs) {
                        struct ir3_instruction *src = get_src(ctx, &nsrc->src)[0];

                        /* NOTE: src might not be in the same block as it comes from
                         * according to the phi.. but in the end the backend assumes
                         * it will be able to assign the same register to each (which
                         * only works if it is assigned in the src block), so insert
                         * an extra mov to make sure the phi src is assigned in the
                         * block it comes from:
                         */
                        src = ir3_MOV(get_block(ctx, nsrc->pred), src, TYPE_U32);

                        ir3_reg_create(instr, 0, IR3_REG_SSA)->instr = src;
                }
        }
}

static void
emit_jump(struct ir3_compile *ctx, nir_jump_instr *jump)
{
        switch (jump->type) {
        case nir_jump_break:
        case nir_jump_continue:
                /* I *think* we can simply just ignore this, and use the
                 * successor block link to figure out where we need to
                 * jump to for break/continue
                 */
                break;
        default:
                compile_error(ctx, "Unhandled NIR jump type: %d\n", jump->type);
                break;
        }
}

static void
emit_instr(struct ir3_compile *ctx, nir_instr *instr)
{
        switch (instr->type) {
        case nir_instr_type_alu:
                emit_alu(ctx, nir_instr_as_alu(instr));
                break;
        case nir_instr_type_intrinsic:
                emit_intrinsic(ctx, nir_instr_as_intrinsic(instr));
                break;
        case nir_instr_type_load_const:
                emit_load_const(ctx, nir_instr_as_load_const(instr));
                break;
        case nir_instr_type_ssa_undef:
                emit_undef(ctx, nir_instr_as_ssa_undef(instr));
                break;
        case nir_instr_type_tex: {
                nir_tex_instr *tex = nir_instr_as_tex(instr);
                /* couple tex instructions get special-cased:
                 */
                switch (tex->op) {
                case nir_texop_txs:
                        emit_tex_txs(ctx, tex);
                        break;
                case nir_texop_query_levels:
                        emit_tex_query_levels(ctx, tex);
                        break;
                default:
                        emit_tex(ctx, tex);
                        break;
                }
                break;
        }
        case nir_instr_type_phi:
                emit_phi(ctx, nir_instr_as_phi(instr));
                break;
        case nir_instr_type_jump:
                emit_jump(ctx, nir_instr_as_jump(instr));
                break;
        case nir_instr_type_call:
        case nir_instr_type_parallel_copy:
                compile_error(ctx, "Unhandled NIR instruction type: %d\n", instr->type);
                break;
        }
}

static struct ir3_block *
get_block(struct ir3_compile *ctx, nir_block *nblock)
{
        struct ir3_block *block;
        struct hash_entry *entry;
        entry = _mesa_hash_table_search(ctx->block_ht, nblock);
        if (entry)
                return entry->data;

        block = ir3_block_create(ctx->ir);
        block->nblock = nblock;
        _mesa_hash_table_insert(ctx->block_ht, nblock, block);

        return block;
}

static void
emit_block(struct ir3_compile *ctx, nir_block *nblock)
{
        struct ir3_block *block = get_block(ctx, nblock);

        for (int i = 0; i < ARRAY_SIZE(block->successors); i++) {
                if (nblock->successors[i]) {
                        block->successors[i] =
                                get_block(ctx, nblock->successors[i]);
                }
        }

        ctx->block = block;
        list_addtail(&block->node, &ctx->ir->block_list);

        /* re-emit addr register in each block if needed: */
        _mesa_hash_table_destroy(ctx->addr_ht, NULL);
        ctx->addr_ht = NULL;

        nir_foreach_instr(nblock, instr) {
                emit_instr(ctx, instr);
                if (ctx->error)
                        return;
        }
}

static void emit_cf_list(struct ir3_compile *ctx, struct exec_list *list);

static void
emit_if(struct ir3_compile *ctx, nir_if *nif)
{
        struct ir3_instruction *condition = get_src(ctx, &nif->condition)[0];

        ctx->block->condition =
                get_predicate(ctx, ir3_b2n(condition->block, condition));

        emit_cf_list(ctx, &nif->then_list);
        emit_cf_list(ctx, &nif->else_list);
}

static void
emit_loop(struct ir3_compile *ctx, nir_loop *nloop)
{
        emit_cf_list(ctx, &nloop->body);
}

static void
emit_cf_list(struct ir3_compile *ctx, struct exec_list *list)
{
        foreach_list_typed(nir_cf_node, node, node, list) {
                switch (node->type) {
                case nir_cf_node_block:
                        emit_block(ctx, nir_cf_node_as_block(node));
                        break;
                case nir_cf_node_if:
                        emit_if(ctx, nir_cf_node_as_if(node));
                        break;
                case nir_cf_node_loop:
                        emit_loop(ctx, nir_cf_node_as_loop(node));
                        break;
                case nir_cf_node_function:
                        compile_error(ctx, "TODO\n");
                        break;
                }
        }
}

/* emit stream-out code.  At this point, the current block is the original
 * (nir) end block, and nir ensures that all flow control paths terminate
 * into the end block.  We re-purpose the original end block to generate
 * the 'if (vtxcnt < maxvtxcnt)' condition, then append the conditional
 * block holding stream-out write instructions, followed by the new end
 * block:
 *
 *   blockOrigEnd {
 *      p0.x = (vtxcnt < maxvtxcnt)
 *      // succs: blockStreamOut, blockNewEnd
 *   }
 *   blockStreamOut {
 *      ... stream-out instructions ...
 *      // succs: blockNewEnd
 *   }
 *   blockNewEnd {
 *   }
 */
static void
emit_stream_out(struct ir3_compile *ctx)
{
        struct ir3_shader_variant *v = ctx->so;
        struct ir3 *ir = ctx->ir;
        struct pipe_stream_output_info *strmout =
                        &ctx->so->shader->stream_output;
        struct ir3_block *orig_end_block, *stream_out_block, *new_end_block;
        struct ir3_instruction *vtxcnt, *maxvtxcnt, *cond;
        struct ir3_instruction *bases[PIPE_MAX_SO_BUFFERS];

        /* create vtxcnt input in input block at top of shader,
         * so that it is seen as live over the entire duration
         * of the shader:
         */
        vtxcnt = create_input(ctx->in_block, 0);
        add_sysval_input(ctx, SYSTEM_VALUE_VERTEX_CNT, vtxcnt);

        maxvtxcnt = create_driver_param(ctx, IR3_DP_VTXCNT_MAX);

        /* at this point, we are at the original 'end' block,
         * re-purpose this block to stream-out condition, then
         * append stream-out block and new-end block
         */
        orig_end_block = ctx->block;

        stream_out_block = ir3_block_create(ir);
        list_addtail(&stream_out_block->node, &ir->block_list);

        new_end_block = ir3_block_create(ir);
        list_addtail(&new_end_block->node, &ir->block_list);

        orig_end_block->successors[0] = stream_out_block;
        orig_end_block->successors[1] = new_end_block;
        stream_out_block->successors[0] = new_end_block;

        /* setup 'if (vtxcnt < maxvtxcnt)' condition: */
        cond = ir3_CMPS_S(ctx->block, vtxcnt, 0, maxvtxcnt, 0);
        cond->regs[0]->num = regid(REG_P0, 0);
        cond->cat2.condition = IR3_COND_LT;

        /* condition goes on previous block to the conditional,
         * since it is used to pick which of the two successor
         * paths to take:
         */
        orig_end_block->condition = cond;

        /* switch to stream_out_block to generate the stream-out
         * instructions:
         */
        ctx->block = stream_out_block;

        /* Calculate base addresses based on vtxcnt.  Instructions
         * generated for bases not used in following loop will be
         * stripped out in the backend.
         */
        for (unsigned i = 0; i < PIPE_MAX_SO_BUFFERS; i++) {
                unsigned stride = strmout->stride[i];
                struct ir3_instruction *base, *off;

                base = create_uniform(ctx, regid(v->first_driver_param + IR3_TFBOS_OFF, i));

                /* 24-bit should be enough: */
                off = ir3_MUL_U(ctx->block, vtxcnt, 0,
                                create_immed(ctx->block, stride * 4), 0);

                bases[i] = ir3_ADD_S(ctx->block, off, 0, base, 0);
        }

        /* Generate the per-output store instructions: */
        for (unsigned i = 0; i < strmout->num_outputs; i++) {
                for (unsigned j = 0; j < strmout->output[i].num_components; j++) {
                        unsigned c = j + strmout->output[i].start_component;
                        struct ir3_instruction *base, *out, *stg;

                        base = bases[strmout->output[i].output_buffer];
                        out = ctx->ir->outputs[regid(strmout->output[i].register_index, c)];

                        stg = ir3_STG(ctx->block, base, 0, out, 0,
                                        create_immed(ctx->block, 1), 0);
                        stg->cat6.type = TYPE_U32;
                        stg->cat6.dst_offset = (strmout->output[i].dst_offset + j) * 4;

                        array_insert(ctx->ir->keeps, stg);
                }
        }

        /* and finally switch to the new_end_block: */
        ctx->block = new_end_block;
}

static void
emit_function(struct ir3_compile *ctx, nir_function_impl *impl)
{
        nir_metadata_require(impl, nir_metadata_block_index);

        emit_cf_list(ctx, &impl->body);
        emit_block(ctx, impl->end_block);

        /* at this point, we should have a single empty block,
         * into which we emit the 'end' instruction.
         */
        compile_assert(ctx, list_empty(&ctx->block->instr_list));

        /* If stream-out (aka transform-feedback) enabled, emit the
         * stream-out instructions, followed by a new empty block (into
         * which the 'end' instruction lands).
         *
         * NOTE: it is done in this order, rather than inserting before
         * we emit end_block, because NIR guarantees that all blocks
         * flow into end_block, and that end_block has no successors.
         * So by re-purposing end_block as the first block of stream-
         * out, we guarantee that all exit paths flow into the stream-
         * out instructions.
         */
        if ((ctx->so->shader->stream_output.num_outputs > 0) &&
                        !ctx->so->key.binning_pass) {
                debug_assert(ctx->so->type == SHADER_VERTEX);
                emit_stream_out(ctx);
        }

        ir3_END(ctx->block);
}

static void
setup_input(struct ir3_compile *ctx, nir_variable *in)
{
        struct ir3_shader_variant *so = ctx->so;
        unsigned array_len = MAX2(glsl_get_length(in->type), 1);
        unsigned ncomp = glsl_get_components(in->type);
        unsigned n = in->data.driver_location;
        unsigned slot = in->data.location;

        DBG("; in: slot=%u, len=%ux%u, drvloc=%u",
                        slot, array_len, ncomp, n);

        so->inputs[n].slot = slot;
        so->inputs[n].compmask = (1 << ncomp) - 1;
        so->inputs_count = MAX2(so->inputs_count, n + 1);
        so->inputs[n].interpolate = in->data.interpolation;

        if (ctx->so->type == SHADER_FRAGMENT) {
                for (int i = 0; i < ncomp; i++) {
                        struct ir3_instruction *instr = NULL;
                        unsigned idx = (n * 4) + i;

                        if (slot == VARYING_SLOT_POS) {
                                so->inputs[n].bary = false;
                                so->frag_coord = true;
                                instr = create_frag_coord(ctx, i);
                        } else if (slot == VARYING_SLOT_FACE) {
                                so->inputs[n].bary = false;
                                so->frag_face = true;
                                instr = create_frag_face(ctx, i);
                        } else {
                                bool use_ldlv = false;

                                /* detect the special case for front/back colors where
                                 * we need to do flat vs smooth shading depending on
                                 * rast state:
                                 */
                                if (in->data.interpolation == INTERP_QUALIFIER_NONE) {
                                        switch (slot) {
                                        case VARYING_SLOT_COL0:
                                        case VARYING_SLOT_COL1:
                                        case VARYING_SLOT_BFC0:
                                        case VARYING_SLOT_BFC1:
                                                so->inputs[n].rasterflat = true;
                                                break;
                                        default:
                                                break;
                                        }
                                }

                                if (ctx->flat_bypass) {
                                        if ((so->inputs[n].interpolate == INTERP_QUALIFIER_FLAT) ||
                                                        (so->inputs[n].rasterflat && ctx->so->key.rasterflat))
                                                use_ldlv = true;
                                }

                                so->inputs[n].bary = true;

                                instr = create_frag_input(ctx, use_ldlv);
                        }

                        ctx->ir->inputs[idx] = instr;
                }
        } else if (ctx->so->type == SHADER_VERTEX) {
                for (int i = 0; i < ncomp; i++) {
                        unsigned idx = (n * 4) + i;
                        ctx->ir->inputs[idx] = create_input(ctx->block, idx);
                }
        } else {
                compile_error(ctx, "unknown shader type: %d\n", ctx->so->type);
        }

        if (so->inputs[n].bary || (ctx->so->type == SHADER_VERTEX)) {
                so->total_in += ncomp;
        }
}

static void
setup_output(struct ir3_compile *ctx, nir_variable *out)
{
        struct ir3_shader_variant *so = ctx->so;
        unsigned array_len = MAX2(glsl_get_length(out->type), 1);
        unsigned ncomp = glsl_get_components(out->type);
        unsigned n = out->data.driver_location;
        unsigned slot = out->data.location;
        unsigned comp = 0;

        DBG("; out: slot=%u, len=%ux%u, drvloc=%u",
                        slot, array_len, ncomp, n);

        if (ctx->so->type == SHADER_FRAGMENT) {
                switch (slot) {
                case FRAG_RESULT_DEPTH:
                        comp = 2;  /* tgsi will write to .z component */
                        so->writes_pos = true;
                        break;
                case FRAG_RESULT_COLOR:
                        so->color0_mrt = 1;
                        break;
                default:
                        if (slot >= FRAG_RESULT_DATA0)
                                break;
                        compile_error(ctx, "unknown FS output name: %s\n",
                                        gl_frag_result_name(slot));
                }
        } else if (ctx->so->type == SHADER_VERTEX) {
                switch (slot) {
                case VARYING_SLOT_POS:
                        so->writes_pos = true;
                        break;
                case VARYING_SLOT_PSIZ:
                        so->writes_psize = true;
                        break;
                case VARYING_SLOT_COL0:
                case VARYING_SLOT_COL1:
                case VARYING_SLOT_BFC0:
                case VARYING_SLOT_BFC1:
                case VARYING_SLOT_FOGC:
                case VARYING_SLOT_CLIP_DIST0:
                case VARYING_SLOT_CLIP_DIST1:
                        break;
                case VARYING_SLOT_CLIP_VERTEX:
                        /* handled entirely in nir_lower_clip: */
                        return;
                default:
                        if (slot >= VARYING_SLOT_VAR0)
                                break;
                        if ((VARYING_SLOT_TEX0 <= slot) && (slot <= VARYING_SLOT_TEX7))
                                break;
                        compile_error(ctx, "unknown VS output name: %s\n",
                                        gl_varying_slot_name(slot));
                }
        } else {
                compile_error(ctx, "unknown shader type: %d\n", ctx->so->type);
        }

        compile_assert(ctx, n < ARRAY_SIZE(so->outputs));

        so->outputs[n].slot = slot;
        so->outputs[n].regid = regid(n, comp);
        so->outputs_count = MAX2(so->outputs_count, n + 1);

        for (int i = 0; i < ncomp; i++) {
                unsigned idx = (n * 4) + i;

                ctx->ir->outputs[idx] = create_immed(ctx->block, fui(0.0));
        }
}

static void
emit_instructions(struct ir3_compile *ctx)
{
        unsigned ninputs, noutputs;
        nir_function_impl *fxn = NULL;

        /* Find the main function: */
        nir_foreach_function(ctx->s, function) {
                compile_assert(ctx, strcmp(function->name, "main") == 0);
                compile_assert(ctx, function->impl);
                fxn = function->impl;
                break;
        }

        ninputs  = exec_list_length(&ctx->s->inputs) * 4;
        noutputs = exec_list_length(&ctx->s->outputs) * 4;

        /* or vtx shaders, we need to leave room for sysvals:
         */
        if (ctx->so->type == SHADER_VERTEX) {
                ninputs += 8;
        }

        ctx->ir = ir3_create(ctx->compiler, ninputs, noutputs);

        /* Create inputs in first block: */
        ctx->block = get_block(ctx, nir_start_block(fxn));
        ctx->in_block = ctx->block;
        list_addtail(&ctx->block->node, &ctx->ir->block_list);

        if (ctx->so->type == SHADER_VERTEX) {
                ctx->ir->ninputs -= 8;
        }

        /* for fragment shader, we have a single input register (usually
         * r0.xy) which is used as the base for bary.f varying fetch instrs:
         */
        if (ctx->so->type == SHADER_FRAGMENT) {
                // TODO maybe a helper for fi since we need it a few places..
                struct ir3_instruction *instr;
                instr = ir3_instr_create(ctx->block, OPC_META_FI);
                ir3_reg_create(instr, 0, 0);
                ir3_reg_create(instr, 0, IR3_REG_SSA);    /* r0.x */
                ir3_reg_create(instr, 0, IR3_REG_SSA);    /* r0.y */
                ctx->frag_pos = instr;
        }

        /* Setup inputs: */
        nir_foreach_variable(var, &ctx->s->inputs) {
                setup_input(ctx, var);
        }

        /* Setup outputs: */
        nir_foreach_variable(var, &ctx->s->outputs) {
                setup_output(ctx, var);
        }

        /* Setup global variables (which should only be arrays): */
        nir_foreach_variable(var, &ctx->s->globals) {
                declare_var(ctx, var);
        }

        /* Setup local variables (which should only be arrays): */
        /* NOTE: need to do something more clever when we support >1 fxn */
        nir_foreach_variable(var, &fxn->locals) {
                declare_var(ctx, var);
        }

        /* And emit the body: */
        ctx->impl = fxn;
        emit_function(ctx, fxn);

        list_for_each_entry (struct ir3_block, block, &ctx->ir->block_list, node) {
                resolve_phis(ctx, block);
        }
}

/* from NIR perspective, we actually have inputs.  But most of the "inputs"
 * for a fragment shader are just bary.f instructions.  The *actual* inputs
 * from the hw perspective are the frag_pos and optionally frag_coord and
 * frag_face.
 */
static void
fixup_frag_inputs(struct ir3_compile *ctx)
{
        struct ir3_shader_variant *so = ctx->so;
        struct ir3 *ir = ctx->ir;
        struct ir3_instruction **inputs;
        struct ir3_instruction *instr;
        int n, regid = 0;

        ir->ninputs = 0;

        n  = 4;  /* always have frag_pos */
        n += COND(so->frag_face, 4);
        n += COND(so->frag_coord, 4);

        inputs = ir3_alloc(ctx->ir, n * (sizeof(struct ir3_instruction *)));

        if (so->frag_face) {
                /* this ultimately gets assigned to hr0.x so doesn't conflict
                 * with frag_coord/frag_pos..
                 */
                inputs[ir->ninputs++] = ctx->frag_face;
                ctx->frag_face->regs[0]->num = 0;

                /* remaining channels not used, but let's avoid confusing
                 * other parts that expect inputs to come in groups of vec4
                 */
                inputs[ir->ninputs++] = NULL;
                inputs[ir->ninputs++] = NULL;
                inputs[ir->ninputs++] = NULL;
        }

        /* since we don't know where to set the regid for frag_coord,
         * we have to use r0.x for it.  But we don't want to *always*
         * use r1.x for frag_pos as that could increase the register
         * footprint on simple shaders:
         */
        if (so->frag_coord) {
                ctx->frag_coord[0]->regs[0]->num = regid++;
                ctx->frag_coord[1]->regs[0]->num = regid++;
                ctx->frag_coord[2]->regs[0]->num = regid++;
                ctx->frag_coord[3]->regs[0]->num = regid++;

                inputs[ir->ninputs++] = ctx->frag_coord[0];
                inputs[ir->ninputs++] = ctx->frag_coord[1];
                inputs[ir->ninputs++] = ctx->frag_coord[2];
                inputs[ir->ninputs++] = ctx->frag_coord[3];
        }

        /* we always have frag_pos: */
        so->pos_regid = regid;

        /* r0.x */
        instr = create_input(ctx->in_block, ir->ninputs);
        instr->regs[0]->num = regid++;
        inputs[ir->ninputs++] = instr;
        ctx->frag_pos->regs[1]->instr = instr;

        /* r0.y */
        instr = create_input(ctx->in_block, ir->ninputs);
        instr->regs[0]->num = regid++;
        inputs[ir->ninputs++] = instr;
        ctx->frag_pos->regs[2]->instr = instr;

        ir->inputs = inputs;
}

int
ir3_compile_shader_nir(struct ir3_compiler *compiler,
                struct ir3_shader_variant *so)
{
        struct ir3_compile *ctx;
        struct ir3 *ir;
        struct ir3_instruction **inputs;
        unsigned i, j, actual_in, inloc;
        int ret = 0, max_bary;

        assert(!so->ir);

        ctx = compile_init(compiler, so);
        if (!ctx) {
                DBG("INIT failed!");
                ret = -1;
                goto out;
        }

        emit_instructions(ctx);

        if (ctx->error) {
                DBG("EMIT failed!");
                ret = -1;
                goto out;
        }

        ir = so->ir = ctx->ir;

        /* keep track of the inputs from TGSI perspective.. */
        inputs = ir->inputs;

        /* but fixup actual inputs for frag shader: */
        if (so->type == SHADER_FRAGMENT)
                fixup_frag_inputs(ctx);

        /* at this point, for binning pass, throw away unneeded outputs: */
        if (so->key.binning_pass) {
                for (i = 0, j = 0; i < so->outputs_count; i++) {
                        unsigned slot = so->outputs[i].slot;

                        /* throw away everything but first position/psize */
                        if ((slot == VARYING_SLOT_POS) || (slot == VARYING_SLOT_PSIZ)) {
                                if (i != j) {
                                        so->outputs[j] = so->outputs[i];
                                        ir->outputs[(j*4)+0] = ir->outputs[(i*4)+0];
                                        ir->outputs[(j*4)+1] = ir->outputs[(i*4)+1];
                                        ir->outputs[(j*4)+2] = ir->outputs[(i*4)+2];
                                        ir->outputs[(j*4)+3] = ir->outputs[(i*4)+3];
                                }
                                j++;
                        }
                }
                so->outputs_count = j;
                ir->noutputs = j * 4;
        }

        /* if we want half-precision outputs, mark the output registers
         * as half:
         */
        if (so->key.half_precision) {
                for (i = 0; i < ir->noutputs; i++) {
                        struct ir3_instruction *out = ir->outputs[i];
                        if (!out)
                                continue;
                        out->regs[0]->flags |= IR3_REG_HALF;
                        /* output could be a fanout (ie. texture fetch output)
                         * in which case we need to propagate the half-reg flag
                         * up to the definer so that RA sees it:
                         */
                        if (out->opc == OPC_META_FO) {
                                out = out->regs[1]->instr;
                                out->regs[0]->flags |= IR3_REG_HALF;
                        }

                        if (out->opc == OPC_MOV) {
                                out->cat1.dst_type = half_type(out->cat1.dst_type);
                        }
                }
        }

        if (fd_mesa_debug & FD_DBG_OPTMSGS) {
                printf("BEFORE CP:\n");
                ir3_print(ir);
        }

        ir3_cp(ir);

        if (fd_mesa_debug & FD_DBG_OPTMSGS) {
                printf("BEFORE GROUPING:\n");
                ir3_print(ir);
        }

        /* Group left/right neighbors, inserting mov's where needed to
         * solve conflicts:
         */
        ir3_group(ir);

        ir3_depth(ir);

        if (fd_mesa_debug & FD_DBG_OPTMSGS) {
                printf("AFTER DEPTH:\n");
                ir3_print(ir);
        }

        ret = ir3_sched(ir);
        if (ret) {
                DBG("SCHED failed!");
                goto out;
        }

        if (fd_mesa_debug & FD_DBG_OPTMSGS) {
                printf("AFTER SCHED:\n");
                ir3_print(ir);
        }

        ret = ir3_ra(ir, so->type, so->frag_coord, so->frag_face);
        if (ret) {
                DBG("RA failed!");
                goto out;
        }

        if (fd_mesa_debug & FD_DBG_OPTMSGS) {
                printf("AFTER RA:\n");
                ir3_print(ir);
        }

        /* fixup input/outputs: */
        for (i = 0; i < so->outputs_count; i++) {
                so->outputs[i].regid = ir->outputs[i*4]->regs[0]->num;
                /* preserve hack for depth output.. tgsi writes depth to .z,
                 * but what we give the hw is the scalar register:
                 */
                if ((so->type == SHADER_FRAGMENT) &&
                        (so->outputs[i].slot == FRAG_RESULT_DEPTH))
                        so->outputs[i].regid += 2;
        }

        /* Note that some or all channels of an input may be unused: */
        actual_in = 0;
        inloc = 0;
        for (i = 0; i < so->inputs_count; i++) {
                unsigned j, regid = ~0, compmask = 0;
                so->inputs[i].ncomp = 0;
                so->inputs[i].inloc = inloc + 8;
                for (j = 0; j < 4; j++) {
                        struct ir3_instruction *in = inputs[(i*4) + j];
                        if (in && !(in->flags & IR3_INSTR_UNUSED)) {
                                compmask |= (1 << j);
                                regid = in->regs[0]->num - j;
                                actual_in++;
                                so->inputs[i].ncomp++;
                                if ((so->type == SHADER_FRAGMENT) && so->inputs[i].bary) {
                                        /* assign inloc: */
                                        assert(in->regs[1]->flags & IR3_REG_IMMED);
                                        in->regs[1]->iim_val = inloc++;
                                }
                        }
                }
                if ((so->type == SHADER_FRAGMENT) && compmask && so->inputs[i].bary)
                        so->varying_in++;
                so->inputs[i].regid = regid;
                so->inputs[i].compmask = compmask;
        }

        /* We need to do legalize after (for frag shader's) the "bary.f"
         * offsets (inloc) have been assigned.
         */
        ir3_legalize(ir, &so->has_samp, &max_bary);

        if (fd_mesa_debug & FD_DBG_OPTMSGS) {
                printf("AFTER LEGALIZE:\n");
                ir3_print(ir);
        }

        /* Note that actual_in counts inputs that are not bary.f'd for FS: */
        if (so->type == SHADER_VERTEX)
                so->total_in = actual_in;
        else
                so->total_in = max_bary + 1;

out:
        if (ret) {
                if (so->ir)
                        ir3_destroy(so->ir);
                so->ir = NULL;
        }
        compile_free(ctx);

        return ret;
}