aboutsummaryrefslogtreecommitdiffstats
path: root/src/gallium/drivers/llvmpipe/lp_bld_depth.c
blob: b25e041375070a4bdc2209b2c2a722a723775bb1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
/**************************************************************************
 *
 * Copyright 2009-2010 VMware, Inc.
 * All Rights Reserved.
 *
 * 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, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/

/**
 * @file
 * Depth/stencil testing to LLVM IR translation.
 *
 * To be done accurately/efficiently the depth/stencil test must be done with
 * the same type/format of the depth/stencil buffer, which implies massaging
 * the incoming depths to fit into place. Using a more straightforward
 * type/format for depth/stencil values internally and only convert when
 * flushing would avoid this, but it would most likely result in depth fighting
 * artifacts.
 *
 * Since we're using linear layout for everything, but we need to deal with
 * 2x2 quads, we need to load/store multiple values and swizzle them into
 * place (we could avoid this by doing depth/stencil testing in linear format,
 * which would be easy for late depth/stencil test as we could do that after
 * the fragment shader loop just as we do for color buffers, but more tricky
 * for early depth test as we'd need both masks and interpolated depth in
 * linear format).
 *
 *
 * @author Jose Fonseca <jfonseca@vmware.com>
 * @author Brian Paul <jfonseca@vmware.com>
 */

#include "pipe/p_state.h"
#include "util/u_format.h"
#include "util/u_cpu_detect.h"

#include "gallivm/lp_bld_type.h"
#include "gallivm/lp_bld_arit.h"
#include "gallivm/lp_bld_bitarit.h"
#include "gallivm/lp_bld_const.h"
#include "gallivm/lp_bld_conv.h"
#include "gallivm/lp_bld_logic.h"
#include "gallivm/lp_bld_flow.h"
#include "gallivm/lp_bld_intr.h"
#include "gallivm/lp_bld_debug.h"
#include "gallivm/lp_bld_swizzle.h"
#include "gallivm/lp_bld_pack.h"

#include "lp_bld_depth.h"


/** Used to select fields from pipe_stencil_state */
enum stencil_op {
   S_FAIL_OP,
   Z_FAIL_OP,
   Z_PASS_OP
};



/**
 * Do the stencil test comparison (compare FB stencil values against ref value).
 * This will be used twice when generating two-sided stencil code.
 * \param stencil  the front/back stencil state
 * \param stencilRef  the stencil reference value, replicated as a vector
 * \param stencilVals  vector of stencil values from framebuffer
 * \return vector mask of pass/fail values (~0 or 0)
 */
static LLVMValueRef
lp_build_stencil_test_single(struct lp_build_context *bld,
                             const struct pipe_stencil_state *stencil,
                             LLVMValueRef stencilRef,
                             LLVMValueRef stencilVals)
{
   LLVMBuilderRef builder = bld->gallivm->builder;
   const unsigned stencilMax = 255; /* XXX fix */
   struct lp_type type = bld->type;
   LLVMValueRef res;

   /*
    * SSE2 has intrinsics for signed comparisons, but not unsigned ones. Values
    * are between 0..255 so ensure we generate the fastest comparisons for
    * wider elements.
    */
   if (type.width <= 8) {
      assert(!type.sign);
   } else {
      assert(type.sign);
   }

   assert(stencil->enabled);

   if (stencil->valuemask != stencilMax) {
      /* compute stencilRef = stencilRef & valuemask */
      LLVMValueRef valuemask = lp_build_const_int_vec(bld->gallivm, type, stencil->valuemask);
      stencilRef = LLVMBuildAnd(builder, stencilRef, valuemask, "");
      /* compute stencilVals = stencilVals & valuemask */
      stencilVals = LLVMBuildAnd(builder, stencilVals, valuemask, "");
   }

   res = lp_build_cmp(bld, stencil->func, stencilRef, stencilVals);

   return res;
}


/**
 * Do the one or two-sided stencil test comparison.
 * \sa lp_build_stencil_test_single
 * \param front_facing  an integer vector mask, indicating front (~0) or back
 *                      (0) facing polygon. If NULL, assume front-facing.
 */
static LLVMValueRef
lp_build_stencil_test(struct lp_build_context *bld,
                      const struct pipe_stencil_state stencil[2],
                      LLVMValueRef stencilRefs[2],
                      LLVMValueRef stencilVals,
                      LLVMValueRef front_facing)
{
   LLVMValueRef res;

   assert(stencil[0].enabled);

   /* do front face test */
   res = lp_build_stencil_test_single(bld, &stencil[0],
                                      stencilRefs[0], stencilVals);

   if (stencil[1].enabled && front_facing != NULL) {
      /* do back face test */
      LLVMValueRef back_res;

      back_res = lp_build_stencil_test_single(bld, &stencil[1],
                                              stencilRefs[1], stencilVals);

      res = lp_build_select(bld, front_facing, res, back_res);
   }

   return res;
}


/**
 * Apply the stencil operator (add/sub/keep/etc) to the given vector
 * of stencil values.
 * \return  new stencil values vector
 */
static LLVMValueRef
lp_build_stencil_op_single(struct lp_build_context *bld,
                           const struct pipe_stencil_state *stencil,
                           enum stencil_op op,
                           LLVMValueRef stencilRef,
                           LLVMValueRef stencilVals)

{
   LLVMBuilderRef builder = bld->gallivm->builder;
   struct lp_type type = bld->type;
   LLVMValueRef res;
   LLVMValueRef max = lp_build_const_int_vec(bld->gallivm, type, 0xff);
   unsigned stencil_op;

   assert(type.sign);

   switch (op) {
   case S_FAIL_OP:
      stencil_op = stencil->fail_op;
      break;
   case Z_FAIL_OP:
      stencil_op = stencil->zfail_op;
      break;
   case Z_PASS_OP:
      stencil_op = stencil->zpass_op;
      break;
   default:
      assert(0 && "Invalid stencil_op mode");
      stencil_op = PIPE_STENCIL_OP_KEEP;
   }

   switch (stencil_op) {
   case PIPE_STENCIL_OP_KEEP:
      res = stencilVals;
      /* we can return early for this case */
      return res;
   case PIPE_STENCIL_OP_ZERO:
      res = bld->zero;
      break;
   case PIPE_STENCIL_OP_REPLACE:
      res = stencilRef;
      break;
   case PIPE_STENCIL_OP_INCR:
      res = lp_build_add(bld, stencilVals, bld->one);
      res = lp_build_min(bld, res, max);
      break;
   case PIPE_STENCIL_OP_DECR:
      res = lp_build_sub(bld, stencilVals, bld->one);
      res = lp_build_max(bld, res, bld->zero);
      break;
   case PIPE_STENCIL_OP_INCR_WRAP:
      res = lp_build_add(bld, stencilVals, bld->one);
      res = LLVMBuildAnd(builder, res, max, "");
      break;
   case PIPE_STENCIL_OP_DECR_WRAP:
      res = lp_build_sub(bld, stencilVals, bld->one);
      res = LLVMBuildAnd(builder, res, max, "");
      break;
   case PIPE_STENCIL_OP_INVERT:
      res = LLVMBuildNot(builder, stencilVals, "");
      res = LLVMBuildAnd(builder, res, max, "");
      break;
   default:
      assert(0 && "bad stencil op mode");
      res = bld->undef;
   }

   return res;
}


/**
 * Do the one or two-sided stencil test op/update.
 */
static LLVMValueRef
lp_build_stencil_op(struct lp_build_context *bld,
                    const struct pipe_stencil_state stencil[2],
                    enum stencil_op op,
                    LLVMValueRef stencilRefs[2],
                    LLVMValueRef stencilVals,
                    LLVMValueRef mask,
                    LLVMValueRef front_facing)

{
   LLVMBuilderRef builder = bld->gallivm->builder;
   LLVMValueRef res;

   assert(stencil[0].enabled);

   /* do front face op */
   res = lp_build_stencil_op_single(bld, &stencil[0], op,
                                     stencilRefs[0], stencilVals);

   if (stencil[1].enabled && front_facing != NULL) {
      /* do back face op */
      LLVMValueRef back_res;

      back_res = lp_build_stencil_op_single(bld, &stencil[1], op,
                                            stencilRefs[1], stencilVals);

      res = lp_build_select(bld, front_facing, res, back_res);
   }

   if (stencil[0].writemask != 0xff ||
       (stencil[1].enabled && front_facing != NULL && stencil[1].writemask != 0xff)) {
      /* mask &= stencil[0].writemask */
      LLVMValueRef writemask = lp_build_const_int_vec(bld->gallivm, bld->type,
                                                      stencil[0].writemask);
      if (stencil[1].enabled && stencil[1].writemask != stencil[0].writemask && front_facing != NULL) {
         LLVMValueRef back_writemask = lp_build_const_int_vec(bld->gallivm, bld->type,
                                                         stencil[1].writemask);
         writemask = lp_build_select(bld, front_facing, writemask, back_writemask);
      }

      mask = LLVMBuildAnd(builder, mask, writemask, "");
      /* res = (res & mask) | (stencilVals & ~mask) */
      res = lp_build_select_bitwise(bld, mask, res, stencilVals);
   }
   else {
      /* res = mask ? res : stencilVals */
      res = lp_build_select(bld, mask, res, stencilVals);
   }

   return res;
}



/**
 * Return a type that matches the depth/stencil format.
 */
struct lp_type
lp_depth_type(const struct util_format_description *format_desc,
              unsigned length)
{
   struct lp_type type;
   unsigned z_swizzle;

   assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
   assert(format_desc->block.width == 1);
   assert(format_desc->block.height == 1);

   memset(&type, 0, sizeof type);
   type.width = format_desc->block.bits;

   z_swizzle = format_desc->swizzle[0];
   if (z_swizzle < 4) {
      if (format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_FLOAT) {
         type.floating = TRUE;
         assert(z_swizzle == 0);
         assert(format_desc->channel[z_swizzle].size == 32);
      }
      else if(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED) {
         assert(format_desc->block.bits <= 32);
         assert(format_desc->channel[z_swizzle].normalized);
         if (format_desc->channel[z_swizzle].size < format_desc->block.bits) {
            /* Prefer signed integers when possible, as SSE has less support
             * for unsigned comparison;
             */
            type.sign = TRUE;
         }
      }
      else
         assert(0);
   }

   type.length = length;

   return type;
}


/**
 * Compute bitmask and bit shift to apply to the incoming fragment Z values
 * and the Z buffer values needed before doing the Z comparison.
 *
 * Note that we leave the Z bits in the position that we find them
 * in the Z buffer (typically 0xffffff00 or 0x00ffffff).  That lets us
 * get by with fewer bit twiddling steps.
 */
static boolean
get_z_shift_and_mask(const struct util_format_description *format_desc,
                     unsigned *shift, unsigned *width, unsigned *mask)
{
   unsigned total_bits;
   unsigned z_swizzle;

   assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
   assert(format_desc->block.width == 1);
   assert(format_desc->block.height == 1);

   /* 64bit d/s format is special already extracted 32 bits */
   total_bits = format_desc->block.bits > 32 ? 32 : format_desc->block.bits;

   z_swizzle = format_desc->swizzle[0];

   if (z_swizzle == UTIL_FORMAT_SWIZZLE_NONE)
      return FALSE;

   *width = format_desc->channel[z_swizzle].size;
   /* & 31 is for the same reason as the 32-bit limit above */
   *shift = format_desc->channel[z_swizzle].shift & 31;

   if (*width == total_bits) {
      *mask = 0xffffffff;
   } else {
      *mask = ((1 << *width) - 1) << *shift;
   }

   return TRUE;
}


/**
 * Compute bitmask and bit shift to apply to the framebuffer pixel values
 * to put the stencil bits in the least significant position.
 * (i.e. 0x000000ff)
 */
static boolean
get_s_shift_and_mask(const struct util_format_description *format_desc,
                     unsigned *shift, unsigned *mask)
{
   unsigned s_swizzle;
   unsigned sz;

   s_swizzle = format_desc->swizzle[1];

   if (s_swizzle == UTIL_FORMAT_SWIZZLE_NONE)
      return FALSE;

   /* just special case 64bit d/s format */
   if (format_desc->block.bits > 32) {
      /* XXX big-endian? */
      assert(format_desc->format == PIPE_FORMAT_Z32_FLOAT_S8X24_UINT);
      *shift = 0;
      *mask = 0xff;
      return TRUE;
   }

   *shift = format_desc->channel[s_swizzle].shift;
   sz = format_desc->channel[s_swizzle].size;
   *mask = (1U << sz) - 1U;

   return TRUE;
}


/**
 * Perform the occlusion test and increase the counter.
 * Test the depth mask. Add the number of channel which has none zero mask
 * into the occlusion counter. e.g. maskvalue is {-1, -1, -1, -1}.
 * The counter will add 4.
 * TODO: could get that out of the fs loop.
 *
 * \param type holds element type of the mask vector.
 * \param maskvalue is the depth test mask.
 * \param counter is a pointer of the uint32 counter.
 */
void
lp_build_occlusion_count(struct gallivm_state *gallivm,
                         struct lp_type type,
                         LLVMValueRef maskvalue,
                         LLVMValueRef counter)
{
   LLVMBuilderRef builder = gallivm->builder;
   LLVMContextRef context = gallivm->context;
   LLVMValueRef countmask = lp_build_const_int_vec(gallivm, type, 1);
   LLVMValueRef count, newcount;

   assert(type.length <= 16);
   assert(type.floating);

   if(util_cpu_caps.has_sse && type.length == 4) {
      const char *movmskintr = "llvm.x86.sse.movmsk.ps";
      const char *popcntintr = "llvm.ctpop.i32";
      LLVMValueRef bits = LLVMBuildBitCast(builder, maskvalue,
                                           lp_build_vec_type(gallivm, type), "");
      bits = lp_build_intrinsic_unary(builder, movmskintr,
                                      LLVMInt32TypeInContext(context), bits);
      count = lp_build_intrinsic_unary(builder, popcntintr,
                                       LLVMInt32TypeInContext(context), bits);
      count = LLVMBuildZExt(builder, count, LLVMIntTypeInContext(context, 64), "");
   }
   else if(util_cpu_caps.has_avx && type.length == 8) {
      const char *movmskintr = "llvm.x86.avx.movmsk.ps.256";
      const char *popcntintr = "llvm.ctpop.i32";
      LLVMValueRef bits = LLVMBuildBitCast(builder, maskvalue,
                                           lp_build_vec_type(gallivm, type), "");
      bits = lp_build_intrinsic_unary(builder, movmskintr,
                                      LLVMInt32TypeInContext(context), bits);
      count = lp_build_intrinsic_unary(builder, popcntintr,
                                       LLVMInt32TypeInContext(context), bits);
      count = LLVMBuildZExt(builder, count, LLVMIntTypeInContext(context, 64), "");
   }
   else {
      unsigned i;
      LLVMValueRef countv = LLVMBuildAnd(builder, maskvalue, countmask, "countv");
      LLVMTypeRef counttype = LLVMIntTypeInContext(context, type.length * 8);
      LLVMTypeRef i8vntype = LLVMVectorType(LLVMInt8TypeInContext(context), type.length * 4);
      LLVMValueRef shufflev, countd;
      LLVMValueRef shuffles[16];
      const char *popcntintr = NULL;

      countv = LLVMBuildBitCast(builder, countv, i8vntype, "");

       for (i = 0; i < type.length; i++) {
          shuffles[i] = lp_build_const_int32(gallivm, 4*i);
       }

       shufflev = LLVMConstVector(shuffles, type.length);
       countd = LLVMBuildShuffleVector(builder, countv, LLVMGetUndef(i8vntype), shufflev, "");
       countd = LLVMBuildBitCast(builder, countd, counttype, "countd");

       /*
        * XXX FIXME
        * this is bad on cpus without popcount (on x86 supported by intel
        * nehalem, amd barcelona, and up - not tied to sse42).
        * Would be much faster to just sum the 4 elements of the vector with
        * some horizontal add (shuffle/add/shuffle/add after the initial and).
        */
       switch (type.length) {
       case 4:
          popcntintr = "llvm.ctpop.i32";
          break;
       case 8:
          popcntintr = "llvm.ctpop.i64";
          break;
       case 16:
          popcntintr = "llvm.ctpop.i128";
          break;
       default:
          assert(0);
       }
       count = lp_build_intrinsic_unary(builder, popcntintr, counttype, countd);

       if (type.length > 8) {
          count = LLVMBuildTrunc(builder, count, LLVMIntTypeInContext(context, 64), "");
       }
       else if (type.length < 8) {
          count = LLVMBuildZExt(builder, count, LLVMIntTypeInContext(context, 64), "");
       }
   }
   newcount = LLVMBuildLoad(builder, counter, "origcount");
   newcount = LLVMBuildAdd(builder, newcount, count, "newcount");
   LLVMBuildStore(builder, newcount, counter);
}


/**
 * Load depth/stencil values.
 * The stored values are linear, swizzle them.
 *
 * \param type  the data type of the fragment depth/stencil values
 * \param format_desc  description of the depth/stencil surface
 * \param is_1d  whether this resource has only one dimension
 * \param loop_counter  the current loop iteration
 * \param depth_ptr  pointer to the depth/stencil values of this 4x4 block
 * \param depth_stride  stride of the depth/stencil buffer
 * \param z_fb  contains z values loaded from fb (may include padding)
 * \param s_fb  contains s values loaded from fb (may include padding)
 */
void
lp_build_depth_stencil_load_swizzled(struct gallivm_state *gallivm,
                                     struct lp_type z_src_type,
                                     const struct util_format_description *format_desc,
                                     boolean is_1d,
                                     LLVMValueRef depth_ptr,
                                     LLVMValueRef depth_stride,
                                     LLVMValueRef *z_fb,
                                     LLVMValueRef *s_fb,
                                     LLVMValueRef loop_counter)
{
   LLVMBuilderRef builder = gallivm->builder;
   LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH / 4];
   LLVMValueRef zs_dst1, zs_dst2;
   LLVMValueRef zs_dst_ptr;
   LLVMValueRef depth_offset1, depth_offset2;
   LLVMTypeRef load_ptr_type;
   unsigned depth_bytes = format_desc->block.bits / 8;
   struct lp_type zs_type = lp_depth_type(format_desc, z_src_type.length);
   struct lp_type zs_load_type = zs_type;

   zs_load_type.length = zs_load_type.length / 2;
   load_ptr_type = LLVMPointerType(lp_build_vec_type(gallivm, zs_load_type), 0);

   if (z_src_type.length == 4) {
      unsigned i;
      LLVMValueRef looplsb = LLVMBuildAnd(builder, loop_counter,
                                          lp_build_const_int32(gallivm, 1), "");
      LLVMValueRef loopmsb = LLVMBuildAnd(builder, loop_counter,
                                          lp_build_const_int32(gallivm, 2), "");
      LLVMValueRef offset2 = LLVMBuildMul(builder, loopmsb,
                                          depth_stride, "");
      depth_offset1 = LLVMBuildMul(builder, looplsb,
                                   lp_build_const_int32(gallivm, depth_bytes * 2), "");
      depth_offset1 = LLVMBuildAdd(builder, depth_offset1, offset2, "");

      /* just concatenate the loaded 2x2 values into 4-wide vector */
      for (i = 0; i < 4; i++) {
         shuffles[i] = lp_build_const_int32(gallivm, i);
      }
   }
   else {
      unsigned i;
      LLVMValueRef loopx2 = LLVMBuildShl(builder, loop_counter,
                                         lp_build_const_int32(gallivm, 1), "");
      assert(z_src_type.length == 8);
      depth_offset1 = LLVMBuildMul(builder, loopx2, depth_stride, "");
      /*
       * We load 2x4 values, and need to swizzle them (order
       * 0,1,4,5,2,3,6,7) - not so hot with avx unfortunately.
       */
      for (i = 0; i < 8; i++) {
         shuffles[i] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2);
      }
   }

   depth_offset2 = LLVMBuildAdd(builder, depth_offset1, depth_stride, "");

   /* Load current z/stencil values from z/stencil buffer */
   zs_dst_ptr = LLVMBuildGEP(builder, depth_ptr, &depth_offset1, 1, "");
   zs_dst_ptr = LLVMBuildBitCast(builder, zs_dst_ptr, load_ptr_type, "");
   zs_dst1 = LLVMBuildLoad(builder, zs_dst_ptr, "");
   if (is_1d) {
      zs_dst2 = lp_build_undef(gallivm, zs_load_type);
   }
   else {
      zs_dst_ptr = LLVMBuildGEP(builder, depth_ptr, &depth_offset2, 1, "");
      zs_dst_ptr = LLVMBuildBitCast(builder, zs_dst_ptr, load_ptr_type, "");
      zs_dst2 = LLVMBuildLoad(builder, zs_dst_ptr, "");
   }

   *z_fb = LLVMBuildShuffleVector(builder, zs_dst1, zs_dst2,
                                  LLVMConstVector(shuffles, zs_type.length), "");
   *s_fb = *z_fb;

   if (format_desc->block.bits < z_src_type.width) {
      /* Extend destination ZS values (e.g., when reading from Z16_UNORM) */
      *z_fb = LLVMBuildZExt(builder, *z_fb,
                            lp_build_int_vec_type(gallivm, z_src_type), "");
   }

   else if (format_desc->block.bits > 32) {
      /* rely on llvm to handle too wide vector we have here nicely */
      unsigned i;
      struct lp_type typex2 = zs_type;
      struct lp_type s_type = zs_type;
      LLVMValueRef shuffles1[LP_MAX_VECTOR_LENGTH / 4];
      LLVMValueRef shuffles2[LP_MAX_VECTOR_LENGTH / 4];
      LLVMValueRef tmp;

      typex2.width = typex2.width / 2;
      typex2.length = typex2.length * 2;
      s_type.width = s_type.width / 2;
      s_type.floating = 0;

      tmp = LLVMBuildBitCast(builder, *z_fb,
                             lp_build_vec_type(gallivm, typex2), "");

      for (i = 0; i < zs_type.length; i++) {
         shuffles1[i] = lp_build_const_int32(gallivm, i * 2);
         shuffles2[i] = lp_build_const_int32(gallivm, i * 2 + 1);
      }
      *z_fb = LLVMBuildShuffleVector(builder, tmp, tmp,
                                     LLVMConstVector(shuffles1, zs_type.length), "");
      *s_fb = LLVMBuildShuffleVector(builder, tmp, tmp,
                                     LLVMConstVector(shuffles2, zs_type.length), "");
      *s_fb = LLVMBuildBitCast(builder, *s_fb,
                               lp_build_vec_type(gallivm, s_type), "");
      lp_build_name(*s_fb, "s_dst");
   }

   lp_build_name(*z_fb, "z_dst");
   lp_build_name(*s_fb, "s_dst");
   lp_build_name(*z_fb, "z_dst");
}

/**
 * Store depth/stencil values.
 * Incoming values are swizzled (typically n 2x2 quads), stored linear.
 * If there's a mask it will do select/store otherwise just store.
 *
 * \param type  the data type of the fragment depth/stencil values
 * \param format_desc  description of the depth/stencil surface
 * \param is_1d  whether this resource has only one dimension
 * \param mask  the alive/dead pixel mask for the quad (vector)
 * \param z_fb  z values read from fb (with padding)
 * \param s_fb  s values read from fb (with padding)
 * \param loop_counter  the current loop iteration
 * \param depth_ptr  pointer to the depth/stencil values of this 4x4 block
 * \param depth_stride  stride of the depth/stencil buffer
 * \param z_value the depth values to store (with padding)
 * \param s_value the stencil values to store (with padding)
 */
void
lp_build_depth_stencil_write_swizzled(struct gallivm_state *gallivm,
                                      struct lp_type z_src_type,
                                      const struct util_format_description *format_desc,
                                      boolean is_1d,
                                      struct lp_build_mask_context *mask,
                                      LLVMValueRef z_fb,
                                      LLVMValueRef s_fb,
                                      LLVMValueRef loop_counter,
                                      LLVMValueRef depth_ptr,
                                      LLVMValueRef depth_stride,
                                      LLVMValueRef z_value,
                                      LLVMValueRef s_value)
{
   struct lp_build_context z_bld;
   LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH / 4];
   LLVMBuilderRef builder = gallivm->builder;
   LLVMValueRef mask_value = NULL;
   LLVMValueRef zs_dst1, zs_dst2;
   LLVMValueRef zs_dst_ptr1, zs_dst_ptr2;
   LLVMValueRef depth_offset1, depth_offset2;
   LLVMTypeRef load_ptr_type;
   unsigned depth_bytes = format_desc->block.bits / 8;
   struct lp_type zs_type = lp_depth_type(format_desc, z_src_type.length);
   struct lp_type z_type = zs_type;
   struct lp_type zs_load_type = zs_type;

   zs_load_type.length = zs_load_type.length / 2;
   load_ptr_type = LLVMPointerType(lp_build_vec_type(gallivm, zs_load_type), 0);

   z_type.width = z_src_type.width;

   lp_build_context_init(&z_bld, gallivm, z_type);

   /*
    * This is far from ideal, at least for late depth write we should do this
    * outside the fs loop to avoid all the swizzle stuff.
    */
   if (z_src_type.length == 4) {
      LLVMValueRef looplsb = LLVMBuildAnd(builder, loop_counter,
                                          lp_build_const_int32(gallivm, 1), "");
      LLVMValueRef loopmsb = LLVMBuildAnd(builder, loop_counter,
                                          lp_build_const_int32(gallivm, 2), "");
      LLVMValueRef offset2 = LLVMBuildMul(builder, loopmsb,
                                          depth_stride, "");
      depth_offset1 = LLVMBuildMul(builder, looplsb,
                                   lp_build_const_int32(gallivm, depth_bytes * 2), "");
      depth_offset1 = LLVMBuildAdd(builder, depth_offset1, offset2, "");
   }
   else {
      unsigned i;
      LLVMValueRef loopx2 = LLVMBuildShl(builder, loop_counter,
                                         lp_build_const_int32(gallivm, 1), "");
      assert(z_src_type.length == 8);
      depth_offset1 = LLVMBuildMul(builder, loopx2, depth_stride, "");
      /*
       * We load 2x4 values, and need to swizzle them (order
       * 0,1,4,5,2,3,6,7) - not so hot with avx unfortunately.
       */
      for (i = 0; i < 8; i++) {
         shuffles[i] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2);
      }
   }

   depth_offset2 = LLVMBuildAdd(builder, depth_offset1, depth_stride, "");

   zs_dst_ptr1 = LLVMBuildGEP(builder, depth_ptr, &depth_offset1, 1, "");
   zs_dst_ptr1 = LLVMBuildBitCast(builder, zs_dst_ptr1, load_ptr_type, "");
   zs_dst_ptr2 = LLVMBuildGEP(builder, depth_ptr, &depth_offset2, 1, "");
   zs_dst_ptr2 = LLVMBuildBitCast(builder, zs_dst_ptr2, load_ptr_type, "");

   if (format_desc->block.bits > 32) {
      s_value = LLVMBuildBitCast(builder, s_value, z_bld.vec_type, "");
   }

   if (mask) {
      mask_value = lp_build_mask_value(mask);
      z_value = lp_build_select(&z_bld, mask_value, z_value, z_fb);
      if (format_desc->block.bits > 32) {
         s_fb = LLVMBuildBitCast(builder, s_fb, z_bld.vec_type, "");
         s_value = lp_build_select(&z_bld, mask_value, s_value, s_fb);
      }
   }

   if (zs_type.width < z_src_type.width) {
      /* Truncate ZS values (e.g., when writing to Z16_UNORM) */
      z_value = LLVMBuildTrunc(builder, z_value,
                               lp_build_int_vec_type(gallivm, zs_type), "");
   }

   if (format_desc->block.bits <= 32) {
      if (z_src_type.length == 4) {
         zs_dst1 = lp_build_extract_range(gallivm, z_value, 0, 2);
         zs_dst2 = lp_build_extract_range(gallivm, z_value, 2, 2);
      }
      else {
         assert(z_src_type.length == 8);
         zs_dst1 = LLVMBuildShuffleVector(builder, z_value, z_value,
                                          LLVMConstVector(&shuffles[0],
                                                          zs_load_type.length), "");
         zs_dst2 = LLVMBuildShuffleVector(builder, z_value, z_value,
                                          LLVMConstVector(&shuffles[4],
                                                          zs_load_type.length), "");
      }
   }
   else {
      if (z_src_type.length == 4) {
         zs_dst1 = lp_build_interleave2(gallivm, z_type,
                                        z_value, s_value, 0);
         zs_dst2 = lp_build_interleave2(gallivm, z_type,
                                        z_value, s_value, 1);
      }
      else {
         unsigned i;
         LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH / 2];
         assert(z_src_type.length == 8);
         for (i = 0; i < 8; i++) {
            shuffles[i*2] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2);
            shuffles[i*2+1] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2 +
                                                   z_src_type.length);
         }
         zs_dst1 = LLVMBuildShuffleVector(builder, z_value, s_value,
                                          LLVMConstVector(&shuffles[0],
                                                          z_src_type.length), "");
         zs_dst2 = LLVMBuildShuffleVector(builder, z_value, s_value,
                                          LLVMConstVector(&shuffles[8],
                                                          z_src_type.length), "");
      }
      zs_dst1 = LLVMBuildBitCast(builder, zs_dst1,
                                 lp_build_vec_type(gallivm, zs_load_type), "");
      zs_dst2 = LLVMBuildBitCast(builder, zs_dst2,
                                 lp_build_vec_type(gallivm, zs_load_type), "");
   }

   LLVMBuildStore(builder, zs_dst1, zs_dst_ptr1);
   if (!is_1d) {
      LLVMBuildStore(builder, zs_dst2, zs_dst_ptr2);
   }
}

/**
 * Generate code for performing depth and/or stencil tests.
 * We operate on a vector of values (typically n 2x2 quads).
 *
 * \param depth  the depth test state
 * \param stencil  the front/back stencil state
 * \param type  the data type of the fragment depth/stencil values
 * \param format_desc  description of the depth/stencil surface
 * \param mask  the alive/dead pixel mask for the quad (vector)
 * \param stencil_refs  the front/back stencil ref values (scalar)
 * \param z_src  the incoming depth/stencil values (n 2x2 quad values, float32)
 * \param zs_dst  the depth/stencil values in framebuffer
 * \param face  contains boolean value indicating front/back facing polygon
 */
void
lp_build_depth_stencil_test(struct gallivm_state *gallivm,
                            const struct pipe_depth_state *depth,
                            const struct pipe_stencil_state stencil[2],
                            struct lp_type z_src_type,
                            const struct util_format_description *format_desc,
                            struct lp_build_mask_context *mask,
                            LLVMValueRef stencil_refs[2],
                            LLVMValueRef z_src,
                            LLVMValueRef z_fb,
                            LLVMValueRef s_fb,
                            LLVMValueRef face,
                            LLVMValueRef *z_value,
                            LLVMValueRef *s_value,
                            boolean do_branch)
{
   LLVMBuilderRef builder = gallivm->builder;
   struct lp_type z_type;
   struct lp_build_context z_bld;
   struct lp_build_context s_bld;
   struct lp_type s_type;
   unsigned z_shift = 0, z_width = 0, z_mask = 0;
   LLVMValueRef z_dst = NULL;
   LLVMValueRef stencil_vals = NULL;
   LLVMValueRef z_bitmask = NULL, stencil_shift = NULL;
   LLVMValueRef z_pass = NULL, s_pass_mask = NULL;
   LLVMValueRef current_mask = lp_build_mask_value(mask);
   LLVMValueRef front_facing = NULL;
   boolean have_z, have_s;

   /*
    * Depths are expected to be between 0 and 1, even if they are stored in
    * floats. Setting these bits here will ensure that the lp_build_conv() call
    * below won't try to unnecessarily clamp the incoming values.
    */
   if(z_src_type.floating) {
      z_src_type.sign = FALSE;
      z_src_type.norm = TRUE;
   }
   else {
      assert(!z_src_type.sign);
      assert(z_src_type.norm);
   }

   /* Pick the type matching the depth-stencil format. */
   z_type = lp_depth_type(format_desc, z_src_type.length);

   /* Pick the intermediate type for depth operations. */
   z_type.width = z_src_type.width;
   assert(z_type.length == z_src_type.length);

   /* FIXME: for non-float depth/stencil might generate better code
    * if we'd always split it up to use 128bit operations.
    * For stencil we'd almost certainly want to pack to 8xi16 values,
    * for z just run twice.
    */

   /* Sanity checking */
   {
      const unsigned z_swizzle = format_desc->swizzle[0];
      const unsigned s_swizzle = format_desc->swizzle[1];

      assert(z_swizzle != UTIL_FORMAT_SWIZZLE_NONE ||
             s_swizzle != UTIL_FORMAT_SWIZZLE_NONE);

      assert(depth->enabled || stencil[0].enabled);

      assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
      assert(format_desc->block.width == 1);
      assert(format_desc->block.height == 1);

      if (stencil[0].enabled) {
         assert(s_swizzle < 4);
         assert(format_desc->channel[s_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED);
         assert(format_desc->channel[s_swizzle].pure_integer);
         assert(!format_desc->channel[s_swizzle].normalized);
         assert(format_desc->channel[s_swizzle].size == 8);
      }

      if (depth->enabled) {
         assert(z_swizzle < 4);
         if (z_type.floating) {
            assert(z_swizzle == 0);
            assert(format_desc->channel[z_swizzle].type ==
                   UTIL_FORMAT_TYPE_FLOAT);
            assert(format_desc->channel[z_swizzle].size == 32);
         }
         else {
            assert(format_desc->channel[z_swizzle].type ==
                   UTIL_FORMAT_TYPE_UNSIGNED);
            assert(format_desc->channel[z_swizzle].normalized);
            assert(!z_type.fixed);
         }
      }
   }


   /* Setup build context for Z vals */
   lp_build_context_init(&z_bld, gallivm, z_type);

   /* Setup build context for stencil vals */
   s_type = lp_int_type(z_type);
   lp_build_context_init(&s_bld, gallivm, s_type);

   /* Compute and apply the Z/stencil bitmasks and shifts.
    */
   {
      unsigned s_shift, s_mask;

      z_dst = z_fb;
      stencil_vals = s_fb;

      have_z = get_z_shift_and_mask(format_desc, &z_shift, &z_width, &z_mask);
      have_s = get_s_shift_and_mask(format_desc, &s_shift, &s_mask);

      if (have_z) {
         if (z_mask != 0xffffffff) {
            z_bitmask = lp_build_const_int_vec(gallivm, z_type, z_mask);
         }

         /*
          * Align the framebuffer Z 's LSB to the right.
          */
         if (z_shift) {
            LLVMValueRef shift = lp_build_const_int_vec(gallivm, z_type, z_shift);
            z_dst = LLVMBuildLShr(builder, z_dst, shift, "z_dst");
         } else if (z_bitmask) {
            z_dst = LLVMBuildAnd(builder, z_dst, z_bitmask, "z_dst");
         } else {
            lp_build_name(z_dst, "z_dst");
         }
      }

      if (have_s) {
         if (s_shift) {
            LLVMValueRef shift = lp_build_const_int_vec(gallivm, s_type, s_shift);
            stencil_vals = LLVMBuildLShr(builder, stencil_vals, shift, "");
            stencil_shift = shift;  /* used below */
         }

         if (s_mask != 0xffffffff) {
            LLVMValueRef mask = lp_build_const_int_vec(gallivm, s_type, s_mask);
            stencil_vals = LLVMBuildAnd(builder, stencil_vals, mask, "");
         }

         lp_build_name(stencil_vals, "s_dst");
      }
   }

   if (stencil[0].enabled) {

      if (face) {
         LLVMValueRef zero = lp_build_const_int32(gallivm, 0);

         /* front_facing = face != 0 ? ~0 : 0 */
         front_facing = LLVMBuildICmp(builder, LLVMIntNE, face, zero, "");
         front_facing = LLVMBuildSExt(builder, front_facing,
                                      LLVMIntTypeInContext(gallivm->context,
                                             s_bld.type.length*s_bld.type.width),
                                      "");
         front_facing = LLVMBuildBitCast(builder, front_facing,
                                         s_bld.int_vec_type, "");
      }

      s_pass_mask = lp_build_stencil_test(&s_bld, stencil,
                                          stencil_refs, stencil_vals,
                                          front_facing);

      /* apply stencil-fail operator */
      {
         LLVMValueRef s_fail_mask = lp_build_andnot(&s_bld, current_mask, s_pass_mask);
         stencil_vals = lp_build_stencil_op(&s_bld, stencil, S_FAIL_OP,
                                            stencil_refs, stencil_vals,
                                            s_fail_mask, front_facing);
      }
   }

   if (depth->enabled) {
      /*
       * Convert fragment Z to the desired type, aligning the LSB to the right.
       */

      assert(z_type.width == z_src_type.width);
      assert(z_type.length == z_src_type.length);
      assert(lp_check_value(z_src_type, z_src));
      if (z_src_type.floating) {
         /*
          * Convert from floating point values
          */

         if (!z_type.floating) {
            z_src = lp_build_clamped_float_to_unsigned_norm(gallivm,
                                                            z_src_type,
                                                            z_width,
                                                            z_src);
         }
      } else {
         /*
          * Convert from unsigned normalized values.
          */

         assert(!z_src_type.sign);
         assert(!z_src_type.fixed);
         assert(z_src_type.norm);
         assert(!z_type.floating);
         if (z_src_type.width > z_width) {
            LLVMValueRef shift = lp_build_const_int_vec(gallivm, z_src_type,
                                                        z_src_type.width - z_width);
            z_src = LLVMBuildLShr(builder, z_src, shift, "");
         }
      }
      assert(lp_check_value(z_type, z_src));

      lp_build_name(z_src, "z_src");

      /* compare src Z to dst Z, returning 'pass' mask */
      z_pass = lp_build_cmp(&z_bld, depth->func, z_src, z_dst);

      /* mask off bits that failed stencil test */
      if (s_pass_mask) {
         current_mask = LLVMBuildAnd(builder, current_mask, s_pass_mask, "");
      }

      if (!stencil[0].enabled) {
         /* We can potentially skip all remaining operations here, but only
          * if stencil is disabled because we still need to update the stencil
          * buffer values.  Don't need to update Z buffer values.
          */
         lp_build_mask_update(mask, z_pass);

         if (do_branch) {
            lp_build_mask_check(mask);
         }
      }

      if (depth->writemask) {
         LLVMValueRef z_pass_mask;

         /* mask off bits that failed Z test */
         z_pass_mask = LLVMBuildAnd(builder, current_mask, z_pass, "");

         /* Mix the old and new Z buffer values.
          * z_dst[i] = zselectmask[i] ? z_src[i] : z_dst[i]
          */
         z_dst = lp_build_select(&z_bld, z_pass_mask, z_src, z_dst);
      }

      if (stencil[0].enabled) {
         /* update stencil buffer values according to z pass/fail result */
         LLVMValueRef z_fail_mask, z_pass_mask;

         /* apply Z-fail operator */
         z_fail_mask = lp_build_andnot(&s_bld, current_mask, z_pass);
         stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_FAIL_OP,
                                            stencil_refs, stencil_vals,
                                            z_fail_mask, front_facing);

         /* apply Z-pass operator */
         z_pass_mask = LLVMBuildAnd(builder, current_mask, z_pass, "");
         stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_PASS_OP,
                                            stencil_refs, stencil_vals,
                                            z_pass_mask, front_facing);
      }
   }
   else {
      /* No depth test: apply Z-pass operator to stencil buffer values which
       * passed the stencil test.
       */
      s_pass_mask = LLVMBuildAnd(builder, current_mask, s_pass_mask, "");
      stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_PASS_OP,
                                         stencil_refs, stencil_vals,
                                         s_pass_mask, front_facing);
   }

   /* Put Z and stencil bits in the right place */
   if (have_z && z_shift) {
      LLVMValueRef shift = lp_build_const_int_vec(gallivm, z_type, z_shift);
      z_dst = LLVMBuildShl(builder, z_dst, shift, "");
   }
   if (stencil_vals && stencil_shift)
      stencil_vals = LLVMBuildShl(builder, stencil_vals,
                                  stencil_shift, "");

   /* Finally, merge the z/stencil values */
   if (format_desc->block.bits <= 32) {
      if (have_z && have_s)
         *z_value = LLVMBuildOr(builder, z_dst, stencil_vals, "");
      else if (have_z)
         *z_value = z_dst;
      else
         *z_value = stencil_vals;
      *s_value = *z_value;
   }
   else {
      *z_value = z_dst;
      *s_value = stencil_vals;
   }

   if (s_pass_mask)
      lp_build_mask_update(mask, s_pass_mask);

   if (depth->enabled && stencil[0].enabled)
      lp_build_mask_update(mask, z_pass);
}