1/*
2 * Copyright © 2015 Broadcom
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24/**
25 * Implements most of the fixed function fragment pipeline in shader code.
26 *
27 * VC4 doesn't have any hardware support for blending, alpha test, logic ops,
28 * or color mask.  Instead, you read the current contents of the destination
29 * from the tile buffer after having waited for the scoreboard (which is
30 * handled by vc4_qpu_emit.c), then do math using your output color and that
31 * destination value, and update the output color appropriately.
32 *
33 * Once this pass is done, the color write will either have one component (for
34 * single sample) with packed argb8888, or 4 components with the per-sample
35 * argb8888 result.
36 */
37
38/**
39 * Lowers fixed-function blending to a load of the destination color and a
40 * series of ALU operations before the store of the output.
41 */
42#include "util/format/u_format.h"
43#include "vc4_qir.h"
44#include "compiler/nir/nir_builder.h"
45#include "compiler/nir/nir_format_convert.h"
46#include "vc4_context.h"
47
48static bool
49blend_depends_on_dst_color(struct vc4_compile *c)
50{
51        return (c->fs_key->blend.blend_enable ||
52                c->fs_key->blend.colormask != 0xf ||
53                c->fs_key->logicop_func != PIPE_LOGICOP_COPY);
54}
55
56/** Emits a load of the previous fragment color from the tile buffer. */
57static nir_ssa_def *
58vc4_nir_get_dst_color(nir_builder *b, int sample)
59{
60        return nir_load_input(b, 1, 32, nir_imm_int(b, 0),
61                              .base = VC4_NIR_TLB_COLOR_READ_INPUT + sample);
62}
63
64static nir_ssa_def *
65vc4_blend_channel_f(nir_builder *b,
66                    nir_ssa_def **src,
67                    nir_ssa_def **dst,
68                    unsigned factor,
69                    int channel)
70{
71        switch(factor) {
72        case PIPE_BLENDFACTOR_ONE:
73                return nir_imm_float(b, 1.0);
74        case PIPE_BLENDFACTOR_SRC_COLOR:
75                return src[channel];
76        case PIPE_BLENDFACTOR_SRC_ALPHA:
77                return src[3];
78        case PIPE_BLENDFACTOR_DST_ALPHA:
79                return dst[3];
80        case PIPE_BLENDFACTOR_DST_COLOR:
81                return dst[channel];
82        case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
83                if (channel != 3) {
84                        return nir_fmin(b,
85                                        src[3],
86                                        nir_fsub(b,
87                                                 nir_imm_float(b, 1.0),
88                                                 dst[3]));
89                } else {
90                        return nir_imm_float(b, 1.0);
91                }
92        case PIPE_BLENDFACTOR_CONST_COLOR:
93                return nir_load_system_value(b,
94                                             nir_intrinsic_load_blend_const_color_r_float +
95                                             channel,
96                                             0, 1, 32);
97        case PIPE_BLENDFACTOR_CONST_ALPHA:
98                return nir_load_blend_const_color_a_float(b);
99        case PIPE_BLENDFACTOR_ZERO:
100                return nir_imm_float(b, 0.0);
101        case PIPE_BLENDFACTOR_INV_SRC_COLOR:
102                return nir_fsub(b, nir_imm_float(b, 1.0), src[channel]);
103        case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
104                return nir_fsub(b, nir_imm_float(b, 1.0), src[3]);
105        case PIPE_BLENDFACTOR_INV_DST_ALPHA:
106                return nir_fsub(b, nir_imm_float(b, 1.0), dst[3]);
107        case PIPE_BLENDFACTOR_INV_DST_COLOR:
108                return nir_fsub(b, nir_imm_float(b, 1.0), dst[channel]);
109        case PIPE_BLENDFACTOR_INV_CONST_COLOR:
110                return nir_fsub(b, nir_imm_float(b, 1.0),
111                                nir_load_system_value(b,
112                                                      nir_intrinsic_load_blend_const_color_r_float +
113                                                      channel,
114                                                      0, 1, 32));
115        case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
116                return nir_fsub(b, nir_imm_float(b, 1.0),
117                                nir_load_blend_const_color_a_float(b));
118
119        default:
120        case PIPE_BLENDFACTOR_SRC1_COLOR:
121        case PIPE_BLENDFACTOR_SRC1_ALPHA:
122        case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
123        case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
124                /* Unsupported. */
125                fprintf(stderr, "Unknown blend factor %d\n", factor);
126                return nir_imm_float(b, 1.0);
127        }
128}
129
130static nir_ssa_def *
131vc4_nir_set_packed_chan(nir_builder *b, nir_ssa_def *src0, nir_ssa_def *src1,
132                        int chan)
133{
134        unsigned chan_mask = 0xff << (chan * 8);
135        return nir_ior(b,
136                       nir_iand(b, src0, nir_imm_int(b, ~chan_mask)),
137                       nir_iand(b, src1, nir_imm_int(b, chan_mask)));
138}
139
140static nir_ssa_def *
141vc4_blend_channel_i(nir_builder *b,
142                    nir_ssa_def *src,
143                    nir_ssa_def *dst,
144                    nir_ssa_def *src_a,
145                    nir_ssa_def *dst_a,
146                    unsigned factor,
147                    int a_chan)
148{
149        switch (factor) {
150        case PIPE_BLENDFACTOR_ONE:
151                return nir_imm_int(b, ~0);
152        case PIPE_BLENDFACTOR_SRC_COLOR:
153                return src;
154        case PIPE_BLENDFACTOR_SRC_ALPHA:
155                return src_a;
156        case PIPE_BLENDFACTOR_DST_ALPHA:
157                return dst_a;
158        case PIPE_BLENDFACTOR_DST_COLOR:
159                return dst;
160        case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
161                return vc4_nir_set_packed_chan(b,
162                                               nir_umin_4x8_vc4(b,
163                                                            src_a,
164                                                            nir_inot(b, dst_a)),
165                                               nir_imm_int(b, ~0),
166                                               a_chan);
167        case PIPE_BLENDFACTOR_CONST_COLOR:
168                return nir_load_blend_const_color_rgba8888_unorm(b);
169        case PIPE_BLENDFACTOR_CONST_ALPHA:
170                return nir_load_blend_const_color_aaaa8888_unorm(b);
171        case PIPE_BLENDFACTOR_ZERO:
172                return nir_imm_int(b, 0);
173        case PIPE_BLENDFACTOR_INV_SRC_COLOR:
174                return nir_inot(b, src);
175        case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
176                return nir_inot(b, src_a);
177        case PIPE_BLENDFACTOR_INV_DST_ALPHA:
178                return nir_inot(b, dst_a);
179        case PIPE_BLENDFACTOR_INV_DST_COLOR:
180                return nir_inot(b, dst);
181        case PIPE_BLENDFACTOR_INV_CONST_COLOR:
182                return nir_inot(b,
183                                nir_load_blend_const_color_rgba8888_unorm(b));
184        case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
185                return nir_inot(b,
186                                nir_load_blend_const_color_aaaa8888_unorm(b));
187
188        default:
189        case PIPE_BLENDFACTOR_SRC1_COLOR:
190        case PIPE_BLENDFACTOR_SRC1_ALPHA:
191        case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
192        case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
193                /* Unsupported. */
194                fprintf(stderr, "Unknown blend factor %d\n", factor);
195                return nir_imm_int(b, ~0);
196        }
197}
198
199static nir_ssa_def *
200vc4_blend_func_f(nir_builder *b, nir_ssa_def *src, nir_ssa_def *dst,
201                 unsigned func)
202{
203        switch (func) {
204        case PIPE_BLEND_ADD:
205                return nir_fadd(b, src, dst);
206        case PIPE_BLEND_SUBTRACT:
207                return nir_fsub(b, src, dst);
208        case PIPE_BLEND_REVERSE_SUBTRACT:
209                return nir_fsub(b, dst, src);
210        case PIPE_BLEND_MIN:
211                return nir_fmin(b, src, dst);
212        case PIPE_BLEND_MAX:
213                return nir_fmax(b, src, dst);
214
215        default:
216                /* Unsupported. */
217                fprintf(stderr, "Unknown blend func %d\n", func);
218                return src;
219
220        }
221}
222
223static nir_ssa_def *
224vc4_blend_func_i(nir_builder *b, nir_ssa_def *src, nir_ssa_def *dst,
225                 unsigned func)
226{
227        switch (func) {
228        case PIPE_BLEND_ADD:
229                return nir_usadd_4x8_vc4(b, src, dst);
230        case PIPE_BLEND_SUBTRACT:
231                return nir_ussub_4x8_vc4(b, src, dst);
232        case PIPE_BLEND_REVERSE_SUBTRACT:
233                return nir_ussub_4x8_vc4(b, dst, src);
234        case PIPE_BLEND_MIN:
235                return nir_umin_4x8_vc4(b, src, dst);
236        case PIPE_BLEND_MAX:
237                return nir_umax_4x8_vc4(b, src, dst);
238
239        default:
240                /* Unsupported. */
241                fprintf(stderr, "Unknown blend func %d\n", func);
242                return src;
243
244        }
245}
246
247static void
248vc4_do_blending_f(struct vc4_compile *c, nir_builder *b, nir_ssa_def **result,
249                  nir_ssa_def **src_color, nir_ssa_def **dst_color)
250{
251        struct pipe_rt_blend_state *blend = &c->fs_key->blend;
252
253        if (!blend->blend_enable) {
254                for (int i = 0; i < 4; i++)
255                        result[i] = src_color[i];
256                return;
257        }
258
259        /* Clamp the src color to [0, 1].  Dest is already clamped. */
260        for (int i = 0; i < 4; i++)
261                src_color[i] = nir_fsat(b, src_color[i]);
262
263        nir_ssa_def *src_blend[4], *dst_blend[4];
264        for (int i = 0; i < 4; i++) {
265                int src_factor = ((i != 3) ? blend->rgb_src_factor :
266                                  blend->alpha_src_factor);
267                int dst_factor = ((i != 3) ? blend->rgb_dst_factor :
268                                  blend->alpha_dst_factor);
269                src_blend[i] = nir_fmul(b, src_color[i],
270                                        vc4_blend_channel_f(b,
271                                                            src_color, dst_color,
272                                                            src_factor, i));
273                dst_blend[i] = nir_fmul(b, dst_color[i],
274                                        vc4_blend_channel_f(b,
275                                                            src_color, dst_color,
276                                                            dst_factor, i));
277        }
278
279        for (int i = 0; i < 4; i++) {
280                result[i] = vc4_blend_func_f(b, src_blend[i], dst_blend[i],
281                                             ((i != 3) ? blend->rgb_func :
282                                              blend->alpha_func));
283        }
284}
285
286static nir_ssa_def *
287vc4_nir_splat(nir_builder *b, nir_ssa_def *src)
288{
289        nir_ssa_def *or1 = nir_ior(b, src, nir_ishl(b, src, nir_imm_int(b, 8)));
290        return nir_ior(b, or1, nir_ishl(b, or1, nir_imm_int(b, 16)));
291}
292
293static nir_ssa_def *
294vc4_do_blending_i(struct vc4_compile *c, nir_builder *b,
295                  nir_ssa_def *src_color, nir_ssa_def *dst_color,
296                  nir_ssa_def *src_float_a)
297{
298        struct pipe_rt_blend_state *blend = &c->fs_key->blend;
299
300        if (!blend->blend_enable)
301                return src_color;
302
303        enum pipe_format color_format = c->fs_key->color_format;
304        const uint8_t *format_swiz = vc4_get_format_swizzle(color_format);
305        nir_ssa_def *imm_0xff = nir_imm_int(b, 0xff);
306        nir_ssa_def *src_a = nir_pack_unorm_4x8(b, src_float_a);
307        nir_ssa_def *dst_a;
308        int alpha_chan;
309        for (alpha_chan = 0; alpha_chan < 4; alpha_chan++) {
310                if (format_swiz[alpha_chan] == 3)
311                        break;
312        }
313        if (alpha_chan != 4) {
314                nir_ssa_def *shift = nir_imm_int(b, alpha_chan * 8);
315                dst_a = vc4_nir_splat(b, nir_iand(b, nir_ushr(b, dst_color,
316                                                              shift), imm_0xff));
317        } else {
318                dst_a = nir_imm_int(b, ~0);
319        }
320
321        nir_ssa_def *src_factor = vc4_blend_channel_i(b,
322                                                      src_color, dst_color,
323                                                      src_a, dst_a,
324                                                      blend->rgb_src_factor,
325                                                      alpha_chan);
326        nir_ssa_def *dst_factor = vc4_blend_channel_i(b,
327                                                      src_color, dst_color,
328                                                      src_a, dst_a,
329                                                      blend->rgb_dst_factor,
330                                                      alpha_chan);
331
332        if (alpha_chan != 4 &&
333            blend->alpha_src_factor != blend->rgb_src_factor) {
334                nir_ssa_def *src_alpha_factor =
335                        vc4_blend_channel_i(b,
336                                            src_color, dst_color,
337                                            src_a, dst_a,
338                                            blend->alpha_src_factor,
339                                            alpha_chan);
340                src_factor = vc4_nir_set_packed_chan(b, src_factor,
341                                                     src_alpha_factor,
342                                                     alpha_chan);
343        }
344        if (alpha_chan != 4 &&
345            blend->alpha_dst_factor != blend->rgb_dst_factor) {
346                nir_ssa_def *dst_alpha_factor =
347                        vc4_blend_channel_i(b,
348                                            src_color, dst_color,
349                                            src_a, dst_a,
350                                            blend->alpha_dst_factor,
351                                            alpha_chan);
352                dst_factor = vc4_nir_set_packed_chan(b, dst_factor,
353                                                     dst_alpha_factor,
354                                                     alpha_chan);
355        }
356        nir_ssa_def *src_blend = nir_umul_unorm_4x8_vc4(b, src_color, src_factor);
357        nir_ssa_def *dst_blend = nir_umul_unorm_4x8_vc4(b, dst_color, dst_factor);
358
359        nir_ssa_def *result =
360                vc4_blend_func_i(b, src_blend, dst_blend, blend->rgb_func);
361        if (alpha_chan != 4 && blend->alpha_func != blend->rgb_func) {
362                nir_ssa_def *result_a = vc4_blend_func_i(b,
363                                                         src_blend,
364                                                         dst_blend,
365                                                         blend->alpha_func);
366                result = vc4_nir_set_packed_chan(b, result, result_a,
367                                                 alpha_chan);
368        }
369        return result;
370}
371
372static nir_ssa_def *
373vc4_logicop(nir_builder *b, int logicop_func,
374            nir_ssa_def *src, nir_ssa_def *dst)
375{
376        switch (logicop_func) {
377        case PIPE_LOGICOP_CLEAR:
378                return nir_imm_int(b, 0);
379        case PIPE_LOGICOP_NOR:
380                return nir_inot(b, nir_ior(b, src, dst));
381        case PIPE_LOGICOP_AND_INVERTED:
382                return nir_iand(b, nir_inot(b, src), dst);
383        case PIPE_LOGICOP_COPY_INVERTED:
384                return nir_inot(b, src);
385        case PIPE_LOGICOP_AND_REVERSE:
386                return nir_iand(b, src, nir_inot(b, dst));
387        case PIPE_LOGICOP_INVERT:
388                return nir_inot(b, dst);
389        case PIPE_LOGICOP_XOR:
390                return nir_ixor(b, src, dst);
391        case PIPE_LOGICOP_NAND:
392                return nir_inot(b, nir_iand(b, src, dst));
393        case PIPE_LOGICOP_AND:
394                return nir_iand(b, src, dst);
395        case PIPE_LOGICOP_EQUIV:
396                return nir_inot(b, nir_ixor(b, src, dst));
397        case PIPE_LOGICOP_NOOP:
398                return dst;
399        case PIPE_LOGICOP_OR_INVERTED:
400                return nir_ior(b, nir_inot(b, src), dst);
401        case PIPE_LOGICOP_OR_REVERSE:
402                return nir_ior(b, src, nir_inot(b, dst));
403        case PIPE_LOGICOP_OR:
404                return nir_ior(b, src, dst);
405        case PIPE_LOGICOP_SET:
406                return nir_imm_int(b, ~0);
407        default:
408                fprintf(stderr, "Unknown logic op %d\n", logicop_func);
409                FALLTHROUGH;
410        case PIPE_LOGICOP_COPY:
411                return src;
412        }
413}
414
415static nir_ssa_def *
416vc4_nir_swizzle_and_pack(struct vc4_compile *c, nir_builder *b,
417                         nir_ssa_def **colors)
418{
419        enum pipe_format color_format = c->fs_key->color_format;
420        const uint8_t *format_swiz = vc4_get_format_swizzle(color_format);
421
422        nir_ssa_def *swizzled[4];
423        for (int i = 0; i < 4; i++) {
424                swizzled[i] = vc4_nir_get_swizzled_channel(b, colors,
425                                                           format_swiz[i]);
426        }
427
428        return nir_pack_unorm_4x8(b,
429                                  nir_vec4(b,
430                                           swizzled[0], swizzled[1],
431                                           swizzled[2], swizzled[3]));
432
433}
434
435static nir_ssa_def *
436vc4_nir_blend_pipeline(struct vc4_compile *c, nir_builder *b, nir_ssa_def *src,
437                       int sample)
438{
439        enum pipe_format color_format = c->fs_key->color_format;
440        const uint8_t *format_swiz = vc4_get_format_swizzle(color_format);
441        bool srgb = util_format_is_srgb(color_format);
442
443        /* Pull out the float src/dst color components. */
444        nir_ssa_def *packed_dst_color = vc4_nir_get_dst_color(b, sample);
445        nir_ssa_def *dst_vec4 = nir_unpack_unorm_4x8(b, packed_dst_color);
446        nir_ssa_def *src_color[4], *unpacked_dst_color[4];
447        for (unsigned i = 0; i < 4; i++) {
448                src_color[i] = nir_channel(b, src, i);
449                unpacked_dst_color[i] = nir_channel(b, dst_vec4, i);
450        }
451
452        if (c->fs_key->sample_alpha_to_one && c->fs_key->msaa)
453                src_color[3] = nir_imm_float(b, 1.0);
454
455        nir_ssa_def *packed_color;
456        if (srgb) {
457                /* Unswizzle the destination color. */
458                nir_ssa_def *dst_color[4];
459                for (unsigned i = 0; i < 4; i++) {
460                        dst_color[i] = vc4_nir_get_swizzled_channel(b,
461                                                                    unpacked_dst_color,
462                                                                    format_swiz[i]);
463                }
464
465                /* Turn dst color to linear. */
466                for (int i = 0; i < 3; i++)
467                        dst_color[i] = nir_format_srgb_to_linear(b, dst_color[i]);
468
469                nir_ssa_def *blend_color[4];
470                vc4_do_blending_f(c, b, blend_color, src_color, dst_color);
471
472                /* sRGB encode the output color */
473                for (int i = 0; i < 3; i++)
474                        blend_color[i] = nir_format_linear_to_srgb(b, blend_color[i]);
475
476                packed_color = vc4_nir_swizzle_and_pack(c, b, blend_color);
477        } else {
478                nir_ssa_def *packed_src_color =
479                        vc4_nir_swizzle_and_pack(c, b, src_color);
480
481                packed_color =
482                        vc4_do_blending_i(c, b,
483                                          packed_src_color, packed_dst_color,
484                                          src_color[3]);
485        }
486
487        packed_color = vc4_logicop(b, c->fs_key->logicop_func,
488                                   packed_color, packed_dst_color);
489
490        /* If the bit isn't set in the color mask, then just return the
491         * original dst color, instead.
492         */
493        uint32_t colormask = 0xffffffff;
494        for (int i = 0; i < 4; i++) {
495                if (format_swiz[i] < 4 &&
496                    !(c->fs_key->blend.colormask & (1 << format_swiz[i]))) {
497                        colormask &= ~(0xff << (i * 8));
498                }
499        }
500
501        return nir_ior(b,
502                       nir_iand(b, packed_color,
503                                nir_imm_int(b, colormask)),
504                       nir_iand(b, packed_dst_color,
505                                nir_imm_int(b, ~colormask)));
506}
507
508static void
509vc4_nir_store_sample_mask(struct vc4_compile *c, nir_builder *b,
510                          nir_ssa_def *val)
511{
512        nir_variable *sample_mask = nir_variable_create(c->s, nir_var_shader_out,
513                                                        glsl_uint_type(),
514                                                        "sample_mask");
515        sample_mask->data.driver_location = c->s->num_outputs++;
516        sample_mask->data.location = FRAG_RESULT_SAMPLE_MASK;
517
518        nir_store_output(b, val, nir_imm_int(b, 0),
519                         .base = sample_mask->data.driver_location);
520}
521
522static void
523vc4_nir_lower_blend_instr(struct vc4_compile *c, nir_builder *b,
524                          nir_intrinsic_instr *intr)
525{
526        nir_ssa_def *frag_color = intr->src[0].ssa;
527
528        if (c->fs_key->sample_alpha_to_coverage) {
529                nir_ssa_def *a = nir_channel(b, frag_color, 3);
530
531                /* XXX: We should do a nice dither based on the fragment
532                 * coordinate, instead.
533                 */
534                nir_ssa_def *num_samples = nir_imm_float(b, VC4_MAX_SAMPLES);
535                nir_ssa_def *num_bits = nir_f2i32(b, nir_fmul(b, a, num_samples));
536                nir_ssa_def *bitmask = nir_isub(b,
537                                                nir_ishl(b,
538                                                         nir_imm_int(b, 1),
539                                                         num_bits),
540                                                nir_imm_int(b, 1));
541                vc4_nir_store_sample_mask(c, b, bitmask);
542        }
543
544        /* The TLB color read returns each sample in turn, so if our blending
545         * depends on the destination color, we're going to have to run the
546         * blending function separately for each destination sample value, and
547         * then output the per-sample color using TLB_COLOR_MS.
548         */
549        nir_ssa_def *blend_output;
550        if (c->fs_key->msaa && blend_depends_on_dst_color(c)) {
551                c->msaa_per_sample_output = true;
552
553                nir_ssa_def *samples[4];
554                for (int i = 0; i < VC4_MAX_SAMPLES; i++)
555                        samples[i] = vc4_nir_blend_pipeline(c, b, frag_color, i);
556                blend_output = nir_vec4(b,
557                                        samples[0], samples[1],
558                                        samples[2], samples[3]);
559        } else {
560                blend_output = vc4_nir_blend_pipeline(c, b, frag_color, 0);
561        }
562
563        nir_instr_rewrite_src(&intr->instr, &intr->src[0],
564                              nir_src_for_ssa(blend_output));
565        intr->num_components = blend_output->num_components;
566}
567
568static bool
569vc4_nir_lower_blend_block(nir_block *block, struct vc4_compile *c)
570{
571        nir_foreach_instr_safe(instr, block) {
572                if (instr->type != nir_instr_type_intrinsic)
573                        continue;
574                nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
575                if (intr->intrinsic != nir_intrinsic_store_output)
576                        continue;
577
578                nir_variable *output_var = NULL;
579                nir_foreach_shader_out_variable(var, c->s) {
580                        if (var->data.driver_location ==
581                            nir_intrinsic_base(intr)) {
582                                output_var = var;
583                                break;
584                        }
585                }
586                assert(output_var);
587
588                if (output_var->data.location != FRAG_RESULT_COLOR &&
589                    output_var->data.location != FRAG_RESULT_DATA0) {
590                        continue;
591                }
592
593                nir_function_impl *impl =
594                        nir_cf_node_get_function(&block->cf_node);
595                nir_builder b;
596                nir_builder_init(&b, impl);
597                b.cursor = nir_before_instr(&intr->instr);
598                vc4_nir_lower_blend_instr(c, &b, intr);
599        }
600        return true;
601}
602
603void
604vc4_nir_lower_blend(nir_shader *s, struct vc4_compile *c)
605{
606        nir_foreach_function(function, s) {
607                if (function->impl) {
608                        nir_foreach_block(block, function->impl) {
609                                vc4_nir_lower_blend_block(block, c);
610                        }
611
612                        nir_metadata_preserve(function->impl,
613                                              nir_metadata_block_index |
614                                              nir_metadata_dominance);
615                }
616        }
617
618        /* If we didn't do alpha-to-coverage on the output color, we still
619         * need to pass glSampleMask() through.
620         */
621        if (c->fs_key->sample_coverage && !c->fs_key->sample_alpha_to_coverage) {
622                nir_function_impl *impl = nir_shader_get_entrypoint(s);
623                nir_builder b;
624                nir_builder_init(&b, impl);
625                b.cursor = nir_after_block(nir_impl_last_block(impl));
626
627                vc4_nir_store_sample_mask(c, &b, nir_load_sample_mask_in(&b));
628        }
629}
630