1/*
2 * Copyright (C) 2020 Collabora, Ltd.
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 * Authors (Collabora):
24 *      Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
25 */
26
27/**
28 * Implements framebuffer format conversions in software for Midgard/Bifrost
29 * blend shaders. This pass is designed for a single render target; Midgard
30 * duplicates blend shaders for MRT to simplify everything. A particular
31 * framebuffer format may be categorized as 1) typed load available, 2) typed
32 * unpack available, or 3) software unpack only, and likewise for stores. The
33 * first two types are handled in the compiler backend directly, so this module
34 * is responsible for identifying type 3 formats (hardware dependent) and
35 * inserting appropriate ALU code to perform the conversion from the packed
36 * type to a designated unpacked type, and vice versa.
37 *
38 * The unpacked type depends on the format:
39 *
40 *      - For 32-bit float formats or >8-bit UNORM, 32-bit floats.
41 *      - For other floats, 16-bit floats.
42 *      - For 32-bit ints, 32-bit ints.
43 *      - For 8-bit ints, 8-bit ints.
44 *      - For other ints, 16-bit ints.
45 *
46 * The rationale is to optimize blending and logic op instructions by using the
47 * smallest precision necessary to store the pixel losslessly.
48 */
49
50#include "compiler/nir/nir.h"
51#include "compiler/nir/nir_builder.h"
52#include "compiler/nir/nir_format_convert.h"
53#include "util/format/u_format.h"
54#include "pan_lower_framebuffer.h"
55
56/* Determines the unpacked type best suiting a given format, so the rest of the
57 * pipeline may be adjusted accordingly */
58
59nir_alu_type
60pan_unpacked_type_for_format(const struct util_format_description *desc)
61{
62        int c = util_format_get_first_non_void_channel(desc->format);
63
64        if (c == -1)
65                unreachable("Void format not renderable");
66
67        bool large = (desc->channel[c].size > 16);
68        bool large_norm = (desc->channel[c].size > 8);
69        bool bit8 = (desc->channel[c].size == 8);
70        assert(desc->channel[c].size <= 32);
71
72        if (desc->channel[c].normalized)
73                return large_norm ? nir_type_float32 : nir_type_float16;
74
75        switch (desc->channel[c].type) {
76        case UTIL_FORMAT_TYPE_UNSIGNED:
77                return bit8 ? nir_type_uint8 :
78                        large ? nir_type_uint32 : nir_type_uint16;
79        case UTIL_FORMAT_TYPE_SIGNED:
80                return bit8 ? nir_type_int8 :
81                        large ? nir_type_int32 : nir_type_int16;
82        case UTIL_FORMAT_TYPE_FLOAT:
83                return large ? nir_type_float32 : nir_type_float16;
84        default:
85                unreachable("Format not renderable");
86        }
87}
88
89static bool
90pan_is_format_native(const struct util_format_description *desc, bool broken_ld_special, bool is_store)
91{
92        if (is_store || broken_ld_special)
93                return false;
94
95        if (util_format_is_pure_integer(desc->format) || util_format_is_float(desc->format))
96                return false;
97
98        /* Some formats are missing as typed but have unpacks */
99        if (desc->format == PIPE_FORMAT_R11G11B10_FLOAT)
100                return false;
101
102        return true;
103}
104
105/* Software packs/unpacks, by format class. Packs take in the pixel value typed
106 * as `pan_unpacked_type_for_format` of the format and return an i32vec4
107 * suitable for storing (with components replicated to fill). Unpacks do the
108 * reverse but cannot rely on replication. */
109
110static nir_ssa_def *
111pan_replicate(nir_builder *b, nir_ssa_def *v, unsigned num_components)
112{
113        nir_ssa_def *replicated[4];
114
115        for (unsigned i = 0; i < 4; ++i)
116                replicated[i] = nir_channel(b, v, i % num_components);
117
118        return nir_vec(b, replicated, 4);
119}
120
121static nir_ssa_def *
122pan_unpack_pure_32(nir_builder *b, nir_ssa_def *pack, unsigned num_components)
123{
124        return nir_channels(b, pack, (1 << num_components) - 1);
125}
126
127/* Pure x16 formats are x16 unpacked, so it's similar, but we need to pack
128 * upper/lower halves of course */
129
130static nir_ssa_def *
131pan_pack_pure_16(nir_builder *b, nir_ssa_def *v, unsigned num_components)
132{
133        nir_ssa_def *v4 = pan_replicate(b, v, num_components);
134
135        nir_ssa_def *lo = nir_pack_32_2x16(b, nir_channels(b, v4, 0x3 << 0));
136        nir_ssa_def *hi = nir_pack_32_2x16(b, nir_channels(b, v4, 0x3 << 2));
137
138        return nir_vec4(b, lo, hi, lo, hi);
139}
140
141static nir_ssa_def *
142pan_unpack_pure_16(nir_builder *b, nir_ssa_def *pack, unsigned num_components)
143{
144        nir_ssa_def *unpacked[4];
145
146        assert(num_components <= 4);
147
148        for (unsigned i = 0; i < num_components; i += 2) {
149                nir_ssa_def *halves =
150                        nir_unpack_32_2x16(b, nir_channel(b, pack, i >> 1));
151
152                unpacked[i + 0] = nir_channel(b, halves, 0);
153                unpacked[i + 1] = nir_channel(b, halves, 1);
154        }
155
156        return nir_pad_vec4(b, nir_vec(b, unpacked, num_components));
157}
158
159static nir_ssa_def *
160pan_pack_reorder(nir_builder *b,
161                 const struct util_format_description *desc,
162                 nir_ssa_def *v)
163{
164        unsigned swizzle[4] = { 0, 1, 2, 3 };
165
166        for (unsigned i = 0; i < v->num_components; i++) {
167                if (desc->swizzle[i] <= PIPE_SWIZZLE_W)
168                        swizzle[i] = desc->swizzle[i];
169        }
170
171        return nir_swizzle(b, v, swizzle, v->num_components);
172}
173
174static nir_ssa_def *
175pan_unpack_reorder(nir_builder *b,
176                   const struct util_format_description *desc,
177                   nir_ssa_def *v)
178{
179        unsigned swizzle[4] = { 0, 1, 2, 3 };
180
181        for (unsigned i = 0; i < v->num_components; i++) {
182                if (desc->swizzle[i] <= PIPE_SWIZZLE_W)
183                        swizzle[desc->swizzle[i]] = i;
184        }
185
186        return nir_swizzle(b, v, swizzle, v->num_components);
187}
188
189static nir_ssa_def *
190pan_replicate_4(nir_builder *b, nir_ssa_def *v)
191{
192        return nir_vec4(b, v, v, v, v);
193}
194
195static nir_ssa_def *
196pan_pack_pure_8(nir_builder *b, nir_ssa_def *v, unsigned num_components)
197{
198        return pan_replicate_4(b, nir_pack_32_4x8(b, pan_replicate(b, v, num_components)));
199}
200
201static nir_ssa_def *
202pan_unpack_pure_8(nir_builder *b, nir_ssa_def *pack, unsigned num_components)
203{
204        nir_ssa_def *unpacked = nir_unpack_32_4x8(b, nir_channel(b, pack, 0));
205        return nir_channels(b, unpacked, (1 << num_components) - 1);
206}
207
208/* For <= 8-bits per channel, [U,S]NORM formats are packed like [U,S]NORM 8,
209 * with zeroes spacing out each component as needed */
210
211static nir_ssa_def *
212pan_pack_norm(nir_builder *b, nir_ssa_def *v,
213              unsigned x, unsigned y, unsigned z, unsigned w,
214              bool is_signed)
215{
216        /* If a channel has N bits, 1.0 is encoded as 2^N - 1 for UNORMs and
217         * 2^(N-1) - 1 for SNORMs */
218        nir_ssa_def *scales =
219                is_signed ?
220                nir_imm_vec4_16(b,
221                                (1 << (x - 1)) - 1, (1 << (y - 1)) - 1,
222                                (1 << (z - 1)) - 1, (1 << (w - 1)) - 1) :
223                nir_imm_vec4_16(b,
224                                (1 << x) - 1, (1 << y) - 1,
225                                (1 << z) - 1, (1 << w) - 1);
226
227        /* If a channel has N bits, we pad out to the byte by (8 - N) bits */
228        nir_ssa_def *shifts = nir_imm_ivec4(b, 8 - x, 8 - y, 8 - z, 8 - w);
229
230        nir_ssa_def *clamped =
231                is_signed ?
232                nir_fsat_signed_mali(b, nir_pad_vec4(b, v)) :
233                nir_fsat(b, nir_pad_vec4(b, v));
234
235        nir_ssa_def *f = nir_fmul(b, clamped, scales);
236        nir_ssa_def *u8 = nir_f2u8(b, nir_fround_even(b, f));
237        nir_ssa_def *s = nir_ishl(b, u8, shifts);
238        nir_ssa_def *repl = nir_pack_32_4x8(b, s);
239
240        return pan_replicate_4(b, repl);
241}
242
243static nir_ssa_def *
244pan_pack_unorm(nir_builder *b, nir_ssa_def *v,
245               unsigned x, unsigned y, unsigned z, unsigned w)
246{
247        return pan_pack_norm(b, v, x, y, z, w, false);
248}
249
250static nir_ssa_def *
251pan_pack_snorm(nir_builder *b, nir_ssa_def *v,
252               unsigned x, unsigned y, unsigned z, unsigned w)
253{
254        return pan_pack_norm(b, v, x, y, z, w, true);
255}
256
257/* RGB10_A2 is packed in the tilebuffer as the bottom 3 bytes being the top
258 * 8-bits of RGB and the top byte being RGBA as 2-bits packed. As imirkin
259 * pointed out, this means free conversion to RGBX8 */
260
261static nir_ssa_def *
262pan_pack_unorm_1010102(nir_builder *b, nir_ssa_def *v)
263{
264        nir_ssa_def *scale = nir_imm_vec4(b, 1023.0, 1023.0, 1023.0, 3.0);
265        nir_ssa_def *s = nir_f2u32(b, nir_fround_even(b, nir_fmul(b, nir_fsat(b, v), scale)));
266
267        nir_ssa_def *top8 = nir_ushr(b, s, nir_imm_ivec4(b, 0x2, 0x2, 0x2, 0x2));
268        nir_ssa_def *top8_rgb = nir_pack_32_4x8(b, nir_u2u8(b, top8));
269
270        nir_ssa_def *bottom2 = nir_iand(b, s, nir_imm_ivec4(b, 0x3, 0x3, 0x3, 0x3));
271
272        nir_ssa_def *top =
273                 nir_ior(b,
274                        nir_ior(b,
275                                nir_ishl(b, nir_channel(b, bottom2, 0), nir_imm_int(b, 24 + 0)),
276                                nir_ishl(b, nir_channel(b, bottom2, 1), nir_imm_int(b, 24 + 2))),
277                        nir_ior(b,
278                                nir_ishl(b, nir_channel(b, bottom2, 2), nir_imm_int(b, 24 + 4)),
279                                nir_ishl(b, nir_channel(b, bottom2, 3), nir_imm_int(b, 24 + 6))));
280
281        nir_ssa_def *p = nir_ior(b, top, top8_rgb);
282        return pan_replicate_4(b, p);
283}
284
285/* On the other hand, the pure int RGB10_A2 is identical to the spec */
286
287static nir_ssa_def *
288pan_pack_int_1010102(nir_builder *b, nir_ssa_def *v, bool is_signed)
289{
290        v = nir_u2u32(b, v);
291
292        /* Clamp the values */
293        if (is_signed) {
294                v = nir_imin(b, v, nir_imm_ivec4(b, 511, 511, 511, 1));
295                v = nir_imax(b, v, nir_imm_ivec4(b, -512, -512, -512, -2));
296        } else {
297                v = nir_umin(b, v, nir_imm_ivec4(b, 1023, 1023, 1023, 3));
298        }
299
300        v = nir_ishl(b, v, nir_imm_ivec4(b, 0, 10, 20, 30));
301        v = nir_ior(b,
302                    nir_ior(b, nir_channel(b, v, 0), nir_channel(b, v, 1)),
303                    nir_ior(b, nir_channel(b, v, 2), nir_channel(b, v, 3)));
304
305        return pan_replicate_4(b, v);
306}
307
308static nir_ssa_def *
309pan_unpack_int_1010102(nir_builder *b, nir_ssa_def *packed, bool is_signed)
310{
311        nir_ssa_def *v = pan_replicate_4(b, nir_channel(b, packed, 0));
312
313        /* Left shift all components so the sign bit is on the MSB, and
314         * can be extended by ishr(). The ishl()+[u,i]shr() combination
315         * sets all unused bits to 0 without requiring a mask.
316         */
317        v = nir_ishl(b, v, nir_imm_ivec4(b, 22, 12, 2, 0));
318
319        if (is_signed)
320                v = nir_ishr(b, v, nir_imm_ivec4(b, 22, 22, 22, 30));
321        else
322                v = nir_ushr(b, v, nir_imm_ivec4(b, 22, 22, 22, 30));
323
324        return nir_i2i16(b, v);
325}
326
327/* NIR means we can *finally* catch a break */
328
329static nir_ssa_def *
330pan_pack_r11g11b10(nir_builder *b, nir_ssa_def *v)
331{
332        return pan_replicate_4(b, nir_format_pack_11f11f10f(b,
333                                nir_f2f32(b, v)));
334}
335
336static nir_ssa_def *
337pan_unpack_r11g11b10(nir_builder *b, nir_ssa_def *v)
338{
339        nir_ssa_def *f32 = nir_format_unpack_11f11f10f(b, nir_channel(b, v, 0));
340        nir_ssa_def *f16 = nir_f2fmp(b, f32);
341
342        /* Extend to vec4 with alpha */
343        nir_ssa_def *components[4] = {
344                nir_channel(b, f16, 0),
345                nir_channel(b, f16, 1),
346                nir_channel(b, f16, 2),
347                nir_imm_float16(b, 1.0)
348        };
349
350        return nir_vec(b, components, 4);
351}
352
353/* Wrapper around sRGB conversion */
354
355static nir_ssa_def *
356pan_linear_to_srgb(nir_builder *b, nir_ssa_def *linear)
357{
358        nir_ssa_def *rgb = nir_channels(b, linear, 0x7);
359
360        /* TODO: fp16 native conversion */
361        nir_ssa_def *srgb = nir_f2fmp(b,
362                        nir_format_linear_to_srgb(b, nir_f2f32(b, rgb)));
363
364        nir_ssa_def *comp[4] = {
365                nir_channel(b, srgb, 0),
366                nir_channel(b, srgb, 1),
367                nir_channel(b, srgb, 2),
368                nir_channel(b, linear, 3),
369        };
370
371        return nir_vec(b, comp, 4);
372}
373
374/* Generic dispatches for un/pack regardless of format */
375
376static nir_ssa_def *
377pan_unpack(nir_builder *b,
378                const struct util_format_description *desc,
379                nir_ssa_def *packed)
380{
381        if (desc->is_array) {
382                int c = util_format_get_first_non_void_channel(desc->format);
383                assert(c >= 0);
384                struct util_format_channel_description d = desc->channel[c];
385
386                if (d.size == 32 || d.size == 16) {
387                        assert(!d.normalized);
388                        assert(d.type == UTIL_FORMAT_TYPE_FLOAT || d.pure_integer);
389
390                        return d.size == 32 ? pan_unpack_pure_32(b, packed, desc->nr_channels) :
391                                pan_unpack_pure_16(b, packed, desc->nr_channels);
392                } else if (d.size == 8) {
393                        assert(d.pure_integer);
394                        return pan_unpack_pure_8(b, packed, desc->nr_channels);
395                } else {
396                        unreachable("Unrenderable size");
397                }
398        }
399
400        switch (desc->format) {
401        case PIPE_FORMAT_R10G10B10A2_UINT:
402        case PIPE_FORMAT_B10G10R10A2_UINT:
403                return pan_unpack_int_1010102(b, packed, false);
404        case PIPE_FORMAT_R10G10B10A2_SINT:
405        case PIPE_FORMAT_B10G10R10A2_SINT:
406                return pan_unpack_int_1010102(b, packed, true);
407        case PIPE_FORMAT_R11G11B10_FLOAT:
408                return pan_unpack_r11g11b10(b, packed);
409        default:
410                break;
411        }
412
413        fprintf(stderr, "%s\n", desc->name);
414        unreachable("Unknown format");
415}
416
417static nir_ssa_def *
418pan_pack(nir_builder *b,
419                const struct util_format_description *desc,
420                nir_ssa_def *unpacked)
421{
422        if (desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB)
423                unpacked = pan_linear_to_srgb(b, unpacked);
424
425        if (util_format_is_unorm8(desc))
426                return pan_pack_unorm(b, unpacked, 8, 8, 8, 8);
427
428        if (util_format_is_snorm8(desc->format))
429                return pan_pack_snorm(b, unpacked, 8, 8, 8, 8);
430
431        if (desc->is_array) {
432                int c = util_format_get_first_non_void_channel(desc->format);
433                assert(c >= 0);
434                struct util_format_channel_description d = desc->channel[c];
435
436                if (d.size == 32 || d.size == 16) {
437                        assert(!d.normalized);
438                        assert(d.type == UTIL_FORMAT_TYPE_FLOAT || d.pure_integer);
439
440                        return d.size == 32 ?
441                                pan_replicate(b, unpacked, desc->nr_channels) :
442                                pan_pack_pure_16(b, unpacked, desc->nr_channels);
443                } else if (d.size == 8) {
444                        assert(d.pure_integer);
445                        return pan_pack_pure_8(b, unpacked, desc->nr_channels);
446                } else {
447                        unreachable("Unrenderable size");
448                }
449        }
450
451        switch (desc->format) {
452        case PIPE_FORMAT_B4G4R4A4_UNORM:
453        case PIPE_FORMAT_B4G4R4X4_UNORM:
454        case PIPE_FORMAT_A4R4_UNORM:
455        case PIPE_FORMAT_R4A4_UNORM:
456        case PIPE_FORMAT_A4B4G4R4_UNORM:
457        case PIPE_FORMAT_R4G4B4A4_UNORM:
458                return pan_pack_unorm(b, unpacked, 4, 4, 4, 4);
459        case PIPE_FORMAT_B5G5R5A1_UNORM:
460        case PIPE_FORMAT_R5G5B5A1_UNORM:
461                return pan_pack_unorm(b, unpacked, 5, 6, 5, 1);
462        case PIPE_FORMAT_R5G6B5_UNORM:
463        case PIPE_FORMAT_B5G6R5_UNORM:
464                return pan_pack_unorm(b, unpacked, 5, 6, 5, 0);
465        case PIPE_FORMAT_R10G10B10A2_UNORM:
466        case PIPE_FORMAT_B10G10R10A2_UNORM:
467                return pan_pack_unorm_1010102(b, unpacked);
468        case PIPE_FORMAT_R10G10B10A2_UINT:
469        case PIPE_FORMAT_B10G10R10A2_UINT:
470                return pan_pack_int_1010102(b, unpacked, false);
471        case PIPE_FORMAT_R10G10B10A2_SINT:
472        case PIPE_FORMAT_B10G10R10A2_SINT:
473                return pan_pack_int_1010102(b, unpacked, true);
474        case PIPE_FORMAT_R11G11B10_FLOAT:
475                return pan_pack_r11g11b10(b, unpacked);
476        default:
477                break;
478        }
479
480        fprintf(stderr, "%s\n", desc->name);
481        unreachable("Unknown format");
482}
483
484static void
485pan_lower_fb_store(nir_shader *shader,
486                nir_builder *b,
487                nir_intrinsic_instr *intr,
488                const struct util_format_description *desc,
489                bool reorder_comps)
490{
491        /* For stores, add conversion before */
492        nir_ssa_def *unpacked =
493                nir_ssa_for_src(b, intr->src[1], intr->num_components);
494        unpacked = nir_pad_vec4(b, unpacked);
495
496        /* Re-order the components */
497        if (reorder_comps)
498                unpacked = pan_pack_reorder(b, desc, unpacked);
499
500        nir_ssa_def *packed = pan_pack(b, desc, unpacked);
501
502        nir_store_raw_output_pan(b, packed);
503}
504
505static nir_ssa_def *
506pan_sample_id(nir_builder *b, int sample)
507{
508        return (sample >= 0) ? nir_imm_int(b, sample) : nir_load_sample_id(b);
509}
510
511static void
512pan_lower_fb_load(nir_shader *shader,
513                nir_builder *b,
514                nir_intrinsic_instr *intr,
515                const struct util_format_description *desc,
516                bool reorder_comps,
517                unsigned base, int sample)
518{
519        nir_ssa_def *packed =
520                nir_load_raw_output_pan(b, 4, 32, pan_sample_id(b, sample),
521                                        .base = base);
522
523        /* Convert the raw value */
524        nir_ssa_def *unpacked = pan_unpack(b, desc, packed);
525
526        /* Convert to the size of the load intrinsic.
527         *
528         * We can assume that the type will match with the framebuffer format:
529         *
530         * Page 170 of the PDF of the OpenGL ES 3.0.6 spec says:
531         *
532         * If [UNORM or SNORM, convert to fixed-point]; otherwise no type
533         * conversion is applied. If the values written by the fragment shader
534         * do not match the format(s) of the corresponding color buffer(s),
535         * the result is undefined.
536         */
537
538        unsigned bits = nir_dest_bit_size(intr->dest);
539
540        nir_alu_type src_type = nir_alu_type_get_base_type(
541                        pan_unpacked_type_for_format(desc));
542
543        unpacked = nir_convert_to_bit_size(b, unpacked, src_type, bits);
544        unpacked = nir_resize_vector(b, unpacked, intr->dest.ssa.num_components);
545
546        /* Reorder the components */
547        if (reorder_comps)
548                unpacked = pan_unpack_reorder(b, desc, unpacked);
549
550        nir_ssa_def_rewrite_uses_after(&intr->dest.ssa, unpacked, &intr->instr);
551}
552
553bool
554pan_lower_framebuffer(nir_shader *shader, const enum pipe_format *rt_fmts,
555                      uint8_t raw_fmt_mask, bool is_blend, bool broken_ld_special)
556{
557        if (shader->info.stage != MESA_SHADER_FRAGMENT)
558               return false;
559
560        bool progress = false;
561
562        nir_foreach_function(func, shader) {
563                nir_foreach_block(block, func->impl) {
564                        nir_foreach_instr_safe(instr, block) {
565                                if (instr->type != nir_instr_type_intrinsic)
566                                        continue;
567
568                                nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
569
570                                bool is_load = intr->intrinsic == nir_intrinsic_load_deref;
571                                bool is_store = intr->intrinsic == nir_intrinsic_store_deref;
572
573                                if (!(is_load || (is_store && is_blend)))
574                                        continue;
575
576                                nir_variable *var = nir_intrinsic_get_var(intr, 0);
577
578                                if (var->data.mode != nir_var_shader_out)
579                                        continue;
580
581                                if (var->data.location < FRAG_RESULT_DATA0)
582                                        continue;
583
584                                unsigned base = var->data.driver_location;
585                                unsigned rt = var->data.location - FRAG_RESULT_DATA0;
586
587                                if (rt_fmts[rt] == PIPE_FORMAT_NONE)
588                                        continue;
589
590                                const struct util_format_description *desc =
591                                   util_format_description(rt_fmts[rt]);
592
593                                /* Don't lower */
594                                if (pan_is_format_native(desc, broken_ld_special, is_store))
595                                        continue;
596
597                                /* EXT_shader_framebuffer_fetch requires
598                                 * per-sample loads.
599                                 * MSAA blend shaders are not yet handled, so
600                                 * for now always load sample 0. */
601                                int sample = is_blend ? 0 : -1;
602                                bool reorder_comps = raw_fmt_mask & BITFIELD_BIT(rt);
603
604                                nir_builder b;
605                                nir_builder_init(&b, func->impl);
606
607                                if (is_store) {
608                                        b.cursor = nir_before_instr(instr);
609                                        pan_lower_fb_store(shader, &b, intr, desc, reorder_comps);
610                                } else {
611                                        b.cursor = nir_after_instr(instr);
612                                        pan_lower_fb_load(shader, &b, intr, desc, reorder_comps, base, sample);
613                                }
614
615                                nir_instr_remove(instr);
616
617                                progress = true;
618                        }
619                }
620
621                nir_metadata_preserve(func->impl, nir_metadata_block_index |
622                                nir_metadata_dominance);
623        }
624
625        return progress;
626}
627