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1 /**************************************************************************
2  *
3  * Copyright 2009-2010 VMware, Inc.
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25  *
26  **************************************************************************/
27 
28 /**
29  * @file
30  * Depth/stencil testing to LLVM IR translation.
31  *
32  * To be done accurately/efficiently the depth/stencil test must be done with
33  * the same type/format of the depth/stencil buffer, which implies massaging
34  * the incoming depths to fit into place. Using a more straightforward
35  * type/format for depth/stencil values internally and only convert when
36  * flushing would avoid this, but it would most likely result in depth fighting
37  * artifacts.
38  *
39  * Since we're using linear layout for everything, but we need to deal with
40  * 2x2 quads, we need to load/store multiple values and swizzle them into
41  * place (we could avoid this by doing depth/stencil testing in linear format,
42  * which would be easy for late depth/stencil test as we could do that after
43  * the fragment shader loop just as we do for color buffers, but more tricky
44  * for early depth test as we'd need both masks and interpolated depth in
45  * linear format).
46  *
47  *
48  * @author Jose Fonseca <jfonseca@vmware.com>
49  * @author Brian Paul <jfonseca@vmware.com>
50  */
51 
52 #include "pipe/p_state.h"
53 #include "util/u_format.h"
54 #include "util/u_cpu_detect.h"
55 
56 #include "gallivm/lp_bld_type.h"
57 #include "gallivm/lp_bld_arit.h"
58 #include "gallivm/lp_bld_bitarit.h"
59 #include "gallivm/lp_bld_const.h"
60 #include "gallivm/lp_bld_conv.h"
61 #include "gallivm/lp_bld_logic.h"
62 #include "gallivm/lp_bld_flow.h"
63 #include "gallivm/lp_bld_intr.h"
64 #include "gallivm/lp_bld_debug.h"
65 #include "gallivm/lp_bld_swizzle.h"
66 #include "gallivm/lp_bld_pack.h"
67 
68 #include "lp_bld_depth.h"
69 
70 
71 /** Used to select fields from pipe_stencil_state */
72 enum stencil_op {
73    S_FAIL_OP,
74    Z_FAIL_OP,
75    Z_PASS_OP
76 };
77 
78 
79 
80 /**
81  * Do the stencil test comparison (compare FB stencil values against ref value).
82  * This will be used twice when generating two-sided stencil code.
83  * \param stencil  the front/back stencil state
84  * \param stencilRef  the stencil reference value, replicated as a vector
85  * \param stencilVals  vector of stencil values from framebuffer
86  * \return vector mask of pass/fail values (~0 or 0)
87  */
88 static LLVMValueRef
lp_build_stencil_test_single(struct lp_build_context * bld,const struct pipe_stencil_state * stencil,LLVMValueRef stencilRef,LLVMValueRef stencilVals)89 lp_build_stencil_test_single(struct lp_build_context *bld,
90                              const struct pipe_stencil_state *stencil,
91                              LLVMValueRef stencilRef,
92                              LLVMValueRef stencilVals)
93 {
94    LLVMBuilderRef builder = bld->gallivm->builder;
95    const unsigned stencilMax = 255; /* XXX fix */
96    struct lp_type type = bld->type;
97    LLVMValueRef res;
98 
99    /*
100     * SSE2 has intrinsics for signed comparisons, but not unsigned ones. Values
101     * are between 0..255 so ensure we generate the fastest comparisons for
102     * wider elements.
103     */
104    if (type.width <= 8) {
105       assert(!type.sign);
106    } else {
107       assert(type.sign);
108    }
109 
110    assert(stencil->enabled);
111 
112    if (stencil->valuemask != stencilMax) {
113       /* compute stencilRef = stencilRef & valuemask */
114       LLVMValueRef valuemask = lp_build_const_int_vec(bld->gallivm, type, stencil->valuemask);
115       stencilRef = LLVMBuildAnd(builder, stencilRef, valuemask, "");
116       /* compute stencilVals = stencilVals & valuemask */
117       stencilVals = LLVMBuildAnd(builder, stencilVals, valuemask, "");
118    }
119 
120    res = lp_build_cmp(bld, stencil->func, stencilRef, stencilVals);
121 
122    return res;
123 }
124 
125 
126 /**
127  * Do the one or two-sided stencil test comparison.
128  * \sa lp_build_stencil_test_single
129  * \param front_facing  an integer vector mask, indicating front (~0) or back
130  *                      (0) facing polygon. If NULL, assume front-facing.
131  */
132 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)133 lp_build_stencil_test(struct lp_build_context *bld,
134                       const struct pipe_stencil_state stencil[2],
135                       LLVMValueRef stencilRefs[2],
136                       LLVMValueRef stencilVals,
137                       LLVMValueRef front_facing)
138 {
139    LLVMValueRef res;
140 
141    assert(stencil[0].enabled);
142 
143    /* do front face test */
144    res = lp_build_stencil_test_single(bld, &stencil[0],
145                                       stencilRefs[0], stencilVals);
146 
147    if (stencil[1].enabled && front_facing != NULL) {
148       /* do back face test */
149       LLVMValueRef back_res;
150 
151       back_res = lp_build_stencil_test_single(bld, &stencil[1],
152                                               stencilRefs[1], stencilVals);
153 
154       res = lp_build_select(bld, front_facing, res, back_res);
155    }
156 
157    return res;
158 }
159 
160 
161 /**
162  * Apply the stencil operator (add/sub/keep/etc) to the given vector
163  * of stencil values.
164  * \return  new stencil values vector
165  */
166 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)167 lp_build_stencil_op_single(struct lp_build_context *bld,
168                            const struct pipe_stencil_state *stencil,
169                            enum stencil_op op,
170                            LLVMValueRef stencilRef,
171                            LLVMValueRef stencilVals)
172 
173 {
174    LLVMBuilderRef builder = bld->gallivm->builder;
175    struct lp_type type = bld->type;
176    LLVMValueRef res;
177    LLVMValueRef max = lp_build_const_int_vec(bld->gallivm, type, 0xff);
178    unsigned stencil_op;
179 
180    assert(type.sign);
181 
182    switch (op) {
183    case S_FAIL_OP:
184       stencil_op = stencil->fail_op;
185       break;
186    case Z_FAIL_OP:
187       stencil_op = stencil->zfail_op;
188       break;
189    case Z_PASS_OP:
190       stencil_op = stencil->zpass_op;
191       break;
192    default:
193       assert(0 && "Invalid stencil_op mode");
194       stencil_op = PIPE_STENCIL_OP_KEEP;
195    }
196 
197    switch (stencil_op) {
198    case PIPE_STENCIL_OP_KEEP:
199       res = stencilVals;
200       /* we can return early for this case */
201       return res;
202    case PIPE_STENCIL_OP_ZERO:
203       res = bld->zero;
204       break;
205    case PIPE_STENCIL_OP_REPLACE:
206       res = stencilRef;
207       break;
208    case PIPE_STENCIL_OP_INCR:
209       res = lp_build_add(bld, stencilVals, bld->one);
210       res = lp_build_min(bld, res, max);
211       break;
212    case PIPE_STENCIL_OP_DECR:
213       res = lp_build_sub(bld, stencilVals, bld->one);
214       res = lp_build_max(bld, res, bld->zero);
215       break;
216    case PIPE_STENCIL_OP_INCR_WRAP:
217       res = lp_build_add(bld, stencilVals, bld->one);
218       res = LLVMBuildAnd(builder, res, max, "");
219       break;
220    case PIPE_STENCIL_OP_DECR_WRAP:
221       res = lp_build_sub(bld, stencilVals, bld->one);
222       res = LLVMBuildAnd(builder, res, max, "");
223       break;
224    case PIPE_STENCIL_OP_INVERT:
225       res = LLVMBuildNot(builder, stencilVals, "");
226       res = LLVMBuildAnd(builder, res, max, "");
227       break;
228    default:
229       assert(0 && "bad stencil op mode");
230       res = bld->undef;
231    }
232 
233    return res;
234 }
235 
236 
237 /**
238  * Do the one or two-sided stencil test op/update.
239  */
240 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)241 lp_build_stencil_op(struct lp_build_context *bld,
242                     const struct pipe_stencil_state stencil[2],
243                     enum stencil_op op,
244                     LLVMValueRef stencilRefs[2],
245                     LLVMValueRef stencilVals,
246                     LLVMValueRef mask,
247                     LLVMValueRef front_facing)
248 
249 {
250    LLVMBuilderRef builder = bld->gallivm->builder;
251    LLVMValueRef res;
252 
253    assert(stencil[0].enabled);
254 
255    /* do front face op */
256    res = lp_build_stencil_op_single(bld, &stencil[0], op,
257                                      stencilRefs[0], stencilVals);
258 
259    if (stencil[1].enabled && front_facing != NULL) {
260       /* do back face op */
261       LLVMValueRef back_res;
262 
263       back_res = lp_build_stencil_op_single(bld, &stencil[1], op,
264                                             stencilRefs[1], stencilVals);
265 
266       res = lp_build_select(bld, front_facing, res, back_res);
267    }
268 
269    if (stencil[0].writemask != 0xff ||
270        (stencil[1].enabled && front_facing != NULL && stencil[1].writemask != 0xff)) {
271       /* mask &= stencil[0].writemask */
272       LLVMValueRef writemask = lp_build_const_int_vec(bld->gallivm, bld->type,
273                                                       stencil[0].writemask);
274       if (stencil[1].enabled && stencil[1].writemask != stencil[0].writemask && front_facing != NULL) {
275          LLVMValueRef back_writemask = lp_build_const_int_vec(bld->gallivm, bld->type,
276                                                          stencil[1].writemask);
277          writemask = lp_build_select(bld, front_facing, writemask, back_writemask);
278       }
279 
280       mask = LLVMBuildAnd(builder, mask, writemask, "");
281       /* res = (res & mask) | (stencilVals & ~mask) */
282       res = lp_build_select_bitwise(bld, mask, res, stencilVals);
283    }
284    else {
285       /* res = mask ? res : stencilVals */
286       res = lp_build_select(bld, mask, res, stencilVals);
287    }
288 
289    return res;
290 }
291 
292 
293 
294 /**
295  * Return a type that matches the depth/stencil format.
296  */
297 struct lp_type
lp_depth_type(const struct util_format_description * format_desc,unsigned length)298 lp_depth_type(const struct util_format_description *format_desc,
299               unsigned length)
300 {
301    struct lp_type type;
302    unsigned z_swizzle;
303 
304    assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
305    assert(format_desc->block.width == 1);
306    assert(format_desc->block.height == 1);
307 
308    memset(&type, 0, sizeof type);
309    type.width = format_desc->block.bits;
310 
311    z_swizzle = format_desc->swizzle[0];
312    if (z_swizzle < 4) {
313       if (format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_FLOAT) {
314          type.floating = TRUE;
315          assert(z_swizzle == 0);
316          assert(format_desc->channel[z_swizzle].size == 32);
317       }
318       else if(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED) {
319          assert(format_desc->block.bits <= 32);
320          assert(format_desc->channel[z_swizzle].normalized);
321          if (format_desc->channel[z_swizzle].size < format_desc->block.bits) {
322             /* Prefer signed integers when possible, as SSE has less support
323              * for unsigned comparison;
324              */
325             type.sign = TRUE;
326          }
327       }
328       else
329          assert(0);
330    }
331 
332    type.length = length;
333 
334    return type;
335 }
336 
337 
338 /**
339  * Compute bitmask and bit shift to apply to the incoming fragment Z values
340  * and the Z buffer values needed before doing the Z comparison.
341  *
342  * Note that we leave the Z bits in the position that we find them
343  * in the Z buffer (typically 0xffffff00 or 0x00ffffff).  That lets us
344  * get by with fewer bit twiddling steps.
345  */
346 static boolean
get_z_shift_and_mask(const struct util_format_description * format_desc,unsigned * shift,unsigned * width,unsigned * mask)347 get_z_shift_and_mask(const struct util_format_description *format_desc,
348                      unsigned *shift, unsigned *width, unsigned *mask)
349 {
350    unsigned total_bits;
351    unsigned z_swizzle;
352 
353    assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
354    assert(format_desc->block.width == 1);
355    assert(format_desc->block.height == 1);
356 
357    /* 64bit d/s format is special already extracted 32 bits */
358    total_bits = format_desc->block.bits > 32 ? 32 : format_desc->block.bits;
359 
360    z_swizzle = format_desc->swizzle[0];
361 
362    if (z_swizzle == PIPE_SWIZZLE_NONE)
363       return FALSE;
364 
365    *width = format_desc->channel[z_swizzle].size;
366    /* & 31 is for the same reason as the 32-bit limit above */
367    *shift = format_desc->channel[z_swizzle].shift & 31;
368 
369    if (*width == total_bits) {
370       *mask = 0xffffffff;
371    } else {
372       *mask = ((1 << *width) - 1) << *shift;
373    }
374 
375    return TRUE;
376 }
377 
378 
379 /**
380  * Compute bitmask and bit shift to apply to the framebuffer pixel values
381  * to put the stencil bits in the least significant position.
382  * (i.e. 0x000000ff)
383  */
384 static boolean
get_s_shift_and_mask(const struct util_format_description * format_desc,unsigned * shift,unsigned * mask)385 get_s_shift_and_mask(const struct util_format_description *format_desc,
386                      unsigned *shift, unsigned *mask)
387 {
388    unsigned s_swizzle;
389    unsigned sz;
390 
391    s_swizzle = format_desc->swizzle[1];
392 
393    if (s_swizzle == PIPE_SWIZZLE_NONE)
394       return FALSE;
395 
396    /* just special case 64bit d/s format */
397    if (format_desc->block.bits > 32) {
398       /* XXX big-endian? */
399       assert(format_desc->format == PIPE_FORMAT_Z32_FLOAT_S8X24_UINT);
400       *shift = 0;
401       *mask = 0xff;
402       return TRUE;
403    }
404 
405    *shift = format_desc->channel[s_swizzle].shift;
406    sz = format_desc->channel[s_swizzle].size;
407    *mask = (1U << sz) - 1U;
408 
409    return TRUE;
410 }
411 
412 
413 /**
414  * Perform the occlusion test and increase the counter.
415  * Test the depth mask. Add the number of channel which has none zero mask
416  * into the occlusion counter. e.g. maskvalue is {-1, -1, -1, -1}.
417  * The counter will add 4.
418  * TODO: could get that out of the fs loop.
419  *
420  * \param type holds element type of the mask vector.
421  * \param maskvalue is the depth test mask.
422  * \param counter is a pointer of the uint32 counter.
423  */
424 void
lp_build_occlusion_count(struct gallivm_state * gallivm,struct lp_type type,LLVMValueRef maskvalue,LLVMValueRef counter)425 lp_build_occlusion_count(struct gallivm_state *gallivm,
426                          struct lp_type type,
427                          LLVMValueRef maskvalue,
428                          LLVMValueRef counter)
429 {
430    LLVMBuilderRef builder = gallivm->builder;
431    LLVMContextRef context = gallivm->context;
432    LLVMValueRef countmask = lp_build_const_int_vec(gallivm, type, 1);
433    LLVMValueRef count, newcount;
434 
435    assert(type.length <= 16);
436    assert(type.floating);
437 
438    if(util_cpu_caps.has_sse && type.length == 4) {
439       const char *movmskintr = "llvm.x86.sse.movmsk.ps";
440       const char *popcntintr = "llvm.ctpop.i32";
441       LLVMValueRef bits = LLVMBuildBitCast(builder, maskvalue,
442                                            lp_build_vec_type(gallivm, type), "");
443       bits = lp_build_intrinsic_unary(builder, movmskintr,
444                                       LLVMInt32TypeInContext(context), bits);
445       count = lp_build_intrinsic_unary(builder, popcntintr,
446                                        LLVMInt32TypeInContext(context), bits);
447       count = LLVMBuildZExt(builder, count, LLVMIntTypeInContext(context, 64), "");
448    }
449    else if(util_cpu_caps.has_avx && type.length == 8) {
450       const char *movmskintr = "llvm.x86.avx.movmsk.ps.256";
451       const char *popcntintr = "llvm.ctpop.i32";
452       LLVMValueRef bits = LLVMBuildBitCast(builder, maskvalue,
453                                            lp_build_vec_type(gallivm, type), "");
454       bits = lp_build_intrinsic_unary(builder, movmskintr,
455                                       LLVMInt32TypeInContext(context), bits);
456       count = lp_build_intrinsic_unary(builder, popcntintr,
457                                        LLVMInt32TypeInContext(context), bits);
458       count = LLVMBuildZExt(builder, count, LLVMIntTypeInContext(context, 64), "");
459    }
460    else {
461       unsigned i;
462       LLVMValueRef countv = LLVMBuildAnd(builder, maskvalue, countmask, "countv");
463       LLVMTypeRef counttype = LLVMIntTypeInContext(context, type.length * 8);
464       LLVMTypeRef i8vntype = LLVMVectorType(LLVMInt8TypeInContext(context), type.length * 4);
465       LLVMValueRef shufflev, countd;
466       LLVMValueRef shuffles[16];
467       const char *popcntintr = NULL;
468 
469       countv = LLVMBuildBitCast(builder, countv, i8vntype, "");
470 
471        for (i = 0; i < type.length; i++) {
472           shuffles[i] = lp_build_const_int32(gallivm, 4*i);
473        }
474 
475        shufflev = LLVMConstVector(shuffles, type.length);
476        countd = LLVMBuildShuffleVector(builder, countv, LLVMGetUndef(i8vntype), shufflev, "");
477        countd = LLVMBuildBitCast(builder, countd, counttype, "countd");
478 
479        /*
480         * XXX FIXME
481         * this is bad on cpus without popcount (on x86 supported by intel
482         * nehalem, amd barcelona, and up - not tied to sse42).
483         * Would be much faster to just sum the 4 elements of the vector with
484         * some horizontal add (shuffle/add/shuffle/add after the initial and).
485         */
486        switch (type.length) {
487        case 4:
488           popcntintr = "llvm.ctpop.i32";
489           break;
490        case 8:
491           popcntintr = "llvm.ctpop.i64";
492           break;
493        case 16:
494           popcntintr = "llvm.ctpop.i128";
495           break;
496        default:
497           assert(0);
498        }
499        count = lp_build_intrinsic_unary(builder, popcntintr, counttype, countd);
500 
501        if (type.length > 8) {
502           count = LLVMBuildTrunc(builder, count, LLVMIntTypeInContext(context, 64), "");
503        }
504        else if (type.length < 8) {
505           count = LLVMBuildZExt(builder, count, LLVMIntTypeInContext(context, 64), "");
506        }
507    }
508    newcount = LLVMBuildLoad(builder, counter, "origcount");
509    newcount = LLVMBuildAdd(builder, newcount, count, "newcount");
510    LLVMBuildStore(builder, newcount, counter);
511 }
512 
513 
514 /**
515  * Load depth/stencil values.
516  * The stored values are linear, swizzle them.
517  *
518  * \param type  the data type of the fragment depth/stencil values
519  * \param format_desc  description of the depth/stencil surface
520  * \param is_1d  whether this resource has only one dimension
521  * \param loop_counter  the current loop iteration
522  * \param depth_ptr  pointer to the depth/stencil values of this 4x4 block
523  * \param depth_stride  stride of the depth/stencil buffer
524  * \param z_fb  contains z values loaded from fb (may include padding)
525  * \param s_fb  contains s values loaded from fb (may include padding)
526  */
527 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)528 lp_build_depth_stencil_load_swizzled(struct gallivm_state *gallivm,
529                                      struct lp_type z_src_type,
530                                      const struct util_format_description *format_desc,
531                                      boolean is_1d,
532                                      LLVMValueRef depth_ptr,
533                                      LLVMValueRef depth_stride,
534                                      LLVMValueRef *z_fb,
535                                      LLVMValueRef *s_fb,
536                                      LLVMValueRef loop_counter)
537 {
538    LLVMBuilderRef builder = gallivm->builder;
539    LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH / 4];
540    LLVMValueRef zs_dst1, zs_dst2;
541    LLVMValueRef zs_dst_ptr;
542    LLVMValueRef depth_offset1, depth_offset2;
543    LLVMTypeRef load_ptr_type;
544    unsigned depth_bytes = format_desc->block.bits / 8;
545    struct lp_type zs_type = lp_depth_type(format_desc, z_src_type.length);
546    struct lp_type zs_load_type = zs_type;
547 
548    zs_load_type.length = zs_load_type.length / 2;
549    load_ptr_type = LLVMPointerType(lp_build_vec_type(gallivm, zs_load_type), 0);
550 
551    if (z_src_type.length == 4) {
552       unsigned i;
553       LLVMValueRef looplsb = LLVMBuildAnd(builder, loop_counter,
554                                           lp_build_const_int32(gallivm, 1), "");
555       LLVMValueRef loopmsb = LLVMBuildAnd(builder, loop_counter,
556                                           lp_build_const_int32(gallivm, 2), "");
557       LLVMValueRef offset2 = LLVMBuildMul(builder, loopmsb,
558                                           depth_stride, "");
559       depth_offset1 = LLVMBuildMul(builder, looplsb,
560                                    lp_build_const_int32(gallivm, depth_bytes * 2), "");
561       depth_offset1 = LLVMBuildAdd(builder, depth_offset1, offset2, "");
562 
563       /* just concatenate the loaded 2x2 values into 4-wide vector */
564       for (i = 0; i < 4; i++) {
565          shuffles[i] = lp_build_const_int32(gallivm, i);
566       }
567    }
568    else {
569       unsigned i;
570       LLVMValueRef loopx2 = LLVMBuildShl(builder, loop_counter,
571                                          lp_build_const_int32(gallivm, 1), "");
572       assert(z_src_type.length == 8);
573       depth_offset1 = LLVMBuildMul(builder, loopx2, depth_stride, "");
574       /*
575        * We load 2x4 values, and need to swizzle them (order
576        * 0,1,4,5,2,3,6,7) - not so hot with avx unfortunately.
577        */
578       for (i = 0; i < 8; i++) {
579          shuffles[i] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2);
580       }
581    }
582 
583    depth_offset2 = LLVMBuildAdd(builder, depth_offset1, depth_stride, "");
584 
585    /* Load current z/stencil values from z/stencil buffer */
586    zs_dst_ptr = LLVMBuildGEP(builder, depth_ptr, &depth_offset1, 1, "");
587    zs_dst_ptr = LLVMBuildBitCast(builder, zs_dst_ptr, load_ptr_type, "");
588    zs_dst1 = LLVMBuildLoad(builder, zs_dst_ptr, "");
589    if (is_1d) {
590       zs_dst2 = lp_build_undef(gallivm, zs_load_type);
591    }
592    else {
593       zs_dst_ptr = LLVMBuildGEP(builder, depth_ptr, &depth_offset2, 1, "");
594       zs_dst_ptr = LLVMBuildBitCast(builder, zs_dst_ptr, load_ptr_type, "");
595       zs_dst2 = LLVMBuildLoad(builder, zs_dst_ptr, "");
596    }
597 
598    *z_fb = LLVMBuildShuffleVector(builder, zs_dst1, zs_dst2,
599                                   LLVMConstVector(shuffles, zs_type.length), "");
600    *s_fb = *z_fb;
601 
602    if (format_desc->block.bits < z_src_type.width) {
603       /* Extend destination ZS values (e.g., when reading from Z16_UNORM) */
604       *z_fb = LLVMBuildZExt(builder, *z_fb,
605                             lp_build_int_vec_type(gallivm, z_src_type), "");
606    }
607 
608    else if (format_desc->block.bits > 32) {
609       /* rely on llvm to handle too wide vector we have here nicely */
610       unsigned i;
611       struct lp_type typex2 = zs_type;
612       struct lp_type s_type = zs_type;
613       LLVMValueRef shuffles1[LP_MAX_VECTOR_LENGTH / 4];
614       LLVMValueRef shuffles2[LP_MAX_VECTOR_LENGTH / 4];
615       LLVMValueRef tmp;
616 
617       typex2.width = typex2.width / 2;
618       typex2.length = typex2.length * 2;
619       s_type.width = s_type.width / 2;
620       s_type.floating = 0;
621 
622       tmp = LLVMBuildBitCast(builder, *z_fb,
623                              lp_build_vec_type(gallivm, typex2), "");
624 
625       for (i = 0; i < zs_type.length; i++) {
626          shuffles1[i] = lp_build_const_int32(gallivm, i * 2);
627          shuffles2[i] = lp_build_const_int32(gallivm, i * 2 + 1);
628       }
629       *z_fb = LLVMBuildShuffleVector(builder, tmp, tmp,
630                                      LLVMConstVector(shuffles1, zs_type.length), "");
631       *s_fb = LLVMBuildShuffleVector(builder, tmp, tmp,
632                                      LLVMConstVector(shuffles2, zs_type.length), "");
633       *s_fb = LLVMBuildBitCast(builder, *s_fb,
634                                lp_build_vec_type(gallivm, s_type), "");
635       lp_build_name(*s_fb, "s_dst");
636    }
637 
638    lp_build_name(*z_fb, "z_dst");
639    lp_build_name(*s_fb, "s_dst");
640    lp_build_name(*z_fb, "z_dst");
641 }
642 
643 /**
644  * Store depth/stencil values.
645  * Incoming values are swizzled (typically n 2x2 quads), stored linear.
646  * If there's a mask it will do select/store otherwise just store.
647  *
648  * \param type  the data type of the fragment depth/stencil values
649  * \param format_desc  description of the depth/stencil surface
650  * \param is_1d  whether this resource has only one dimension
651  * \param mask  the alive/dead pixel mask for the quad (vector)
652  * \param z_fb  z values read from fb (with padding)
653  * \param s_fb  s values read from fb (with padding)
654  * \param loop_counter  the current loop iteration
655  * \param depth_ptr  pointer to the depth/stencil values of this 4x4 block
656  * \param depth_stride  stride of the depth/stencil buffer
657  * \param z_value the depth values to store (with padding)
658  * \param s_value the stencil values to store (with padding)
659  */
660 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)661 lp_build_depth_stencil_write_swizzled(struct gallivm_state *gallivm,
662                                       struct lp_type z_src_type,
663                                       const struct util_format_description *format_desc,
664                                       boolean is_1d,
665                                       struct lp_build_mask_context *mask,
666                                       LLVMValueRef z_fb,
667                                       LLVMValueRef s_fb,
668                                       LLVMValueRef loop_counter,
669                                       LLVMValueRef depth_ptr,
670                                       LLVMValueRef depth_stride,
671                                       LLVMValueRef z_value,
672                                       LLVMValueRef s_value)
673 {
674    struct lp_build_context z_bld;
675    LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH / 4];
676    LLVMBuilderRef builder = gallivm->builder;
677    LLVMValueRef mask_value = NULL;
678    LLVMValueRef zs_dst1, zs_dst2;
679    LLVMValueRef zs_dst_ptr1, zs_dst_ptr2;
680    LLVMValueRef depth_offset1, depth_offset2;
681    LLVMTypeRef load_ptr_type;
682    unsigned depth_bytes = format_desc->block.bits / 8;
683    struct lp_type zs_type = lp_depth_type(format_desc, z_src_type.length);
684    struct lp_type z_type = zs_type;
685    struct lp_type zs_load_type = zs_type;
686 
687    zs_load_type.length = zs_load_type.length / 2;
688    load_ptr_type = LLVMPointerType(lp_build_vec_type(gallivm, zs_load_type), 0);
689 
690    z_type.width = z_src_type.width;
691 
692    lp_build_context_init(&z_bld, gallivm, z_type);
693 
694    /*
695     * This is far from ideal, at least for late depth write we should do this
696     * outside the fs loop to avoid all the swizzle stuff.
697     */
698    if (z_src_type.length == 4) {
699       LLVMValueRef looplsb = LLVMBuildAnd(builder, loop_counter,
700                                           lp_build_const_int32(gallivm, 1), "");
701       LLVMValueRef loopmsb = LLVMBuildAnd(builder, loop_counter,
702                                           lp_build_const_int32(gallivm, 2), "");
703       LLVMValueRef offset2 = LLVMBuildMul(builder, loopmsb,
704                                           depth_stride, "");
705       depth_offset1 = LLVMBuildMul(builder, looplsb,
706                                    lp_build_const_int32(gallivm, depth_bytes * 2), "");
707       depth_offset1 = LLVMBuildAdd(builder, depth_offset1, offset2, "");
708    }
709    else {
710       unsigned i;
711       LLVMValueRef loopx2 = LLVMBuildShl(builder, loop_counter,
712                                          lp_build_const_int32(gallivm, 1), "");
713       assert(z_src_type.length == 8);
714       depth_offset1 = LLVMBuildMul(builder, loopx2, depth_stride, "");
715       /*
716        * We load 2x4 values, and need to swizzle them (order
717        * 0,1,4,5,2,3,6,7) - not so hot with avx unfortunately.
718        */
719       for (i = 0; i < 8; i++) {
720          shuffles[i] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2);
721       }
722    }
723 
724    depth_offset2 = LLVMBuildAdd(builder, depth_offset1, depth_stride, "");
725 
726    zs_dst_ptr1 = LLVMBuildGEP(builder, depth_ptr, &depth_offset1, 1, "");
727    zs_dst_ptr1 = LLVMBuildBitCast(builder, zs_dst_ptr1, load_ptr_type, "");
728    zs_dst_ptr2 = LLVMBuildGEP(builder, depth_ptr, &depth_offset2, 1, "");
729    zs_dst_ptr2 = LLVMBuildBitCast(builder, zs_dst_ptr2, load_ptr_type, "");
730 
731    if (format_desc->block.bits > 32) {
732       s_value = LLVMBuildBitCast(builder, s_value, z_bld.vec_type, "");
733    }
734 
735    if (mask) {
736       mask_value = lp_build_mask_value(mask);
737       z_value = lp_build_select(&z_bld, mask_value, z_value, z_fb);
738       if (format_desc->block.bits > 32) {
739          s_fb = LLVMBuildBitCast(builder, s_fb, z_bld.vec_type, "");
740          s_value = lp_build_select(&z_bld, mask_value, s_value, s_fb);
741       }
742    }
743 
744    if (zs_type.width < z_src_type.width) {
745       /* Truncate ZS values (e.g., when writing to Z16_UNORM) */
746       z_value = LLVMBuildTrunc(builder, z_value,
747                                lp_build_int_vec_type(gallivm, zs_type), "");
748    }
749 
750    if (format_desc->block.bits <= 32) {
751       if (z_src_type.length == 4) {
752          zs_dst1 = lp_build_extract_range(gallivm, z_value, 0, 2);
753          zs_dst2 = lp_build_extract_range(gallivm, z_value, 2, 2);
754       }
755       else {
756          assert(z_src_type.length == 8);
757          zs_dst1 = LLVMBuildShuffleVector(builder, z_value, z_value,
758                                           LLVMConstVector(&shuffles[0],
759                                                           zs_load_type.length), "");
760          zs_dst2 = LLVMBuildShuffleVector(builder, z_value, z_value,
761                                           LLVMConstVector(&shuffles[4],
762                                                           zs_load_type.length), "");
763       }
764    }
765    else {
766       if (z_src_type.length == 4) {
767          zs_dst1 = lp_build_interleave2(gallivm, z_type,
768                                         z_value, s_value, 0);
769          zs_dst2 = lp_build_interleave2(gallivm, z_type,
770                                         z_value, s_value, 1);
771       }
772       else {
773          unsigned i;
774          LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH / 2];
775          assert(z_src_type.length == 8);
776          for (i = 0; i < 8; i++) {
777             shuffles[i*2] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2);
778             shuffles[i*2+1] = lp_build_const_int32(gallivm, (i&1) + (i&2) * 2 + (i&4) / 2 +
779                                                    z_src_type.length);
780          }
781          zs_dst1 = LLVMBuildShuffleVector(builder, z_value, s_value,
782                                           LLVMConstVector(&shuffles[0],
783                                                           z_src_type.length), "");
784          zs_dst2 = LLVMBuildShuffleVector(builder, z_value, s_value,
785                                           LLVMConstVector(&shuffles[8],
786                                                           z_src_type.length), "");
787       }
788       zs_dst1 = LLVMBuildBitCast(builder, zs_dst1,
789                                  lp_build_vec_type(gallivm, zs_load_type), "");
790       zs_dst2 = LLVMBuildBitCast(builder, zs_dst2,
791                                  lp_build_vec_type(gallivm, zs_load_type), "");
792    }
793 
794    LLVMBuildStore(builder, zs_dst1, zs_dst_ptr1);
795    if (!is_1d) {
796       LLVMBuildStore(builder, zs_dst2, zs_dst_ptr2);
797    }
798 }
799 
800 /**
801  * Generate code for performing depth and/or stencil tests.
802  * We operate on a vector of values (typically n 2x2 quads).
803  *
804  * \param depth  the depth test state
805  * \param stencil  the front/back stencil state
806  * \param type  the data type of the fragment depth/stencil values
807  * \param format_desc  description of the depth/stencil surface
808  * \param mask  the alive/dead pixel mask for the quad (vector)
809  * \param stencil_refs  the front/back stencil ref values (scalar)
810  * \param z_src  the incoming depth/stencil values (n 2x2 quad values, float32)
811  * \param zs_dst  the depth/stencil values in framebuffer
812  * \param face  contains boolean value indicating front/back facing polygon
813  */
814 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)815 lp_build_depth_stencil_test(struct gallivm_state *gallivm,
816                             const struct pipe_depth_state *depth,
817                             const struct pipe_stencil_state stencil[2],
818                             struct lp_type z_src_type,
819                             const struct util_format_description *format_desc,
820                             struct lp_build_mask_context *mask,
821                             LLVMValueRef stencil_refs[2],
822                             LLVMValueRef z_src,
823                             LLVMValueRef z_fb,
824                             LLVMValueRef s_fb,
825                             LLVMValueRef face,
826                             LLVMValueRef *z_value,
827                             LLVMValueRef *s_value,
828                             boolean do_branch)
829 {
830    LLVMBuilderRef builder = gallivm->builder;
831    struct lp_type z_type;
832    struct lp_build_context z_bld;
833    struct lp_build_context s_bld;
834    struct lp_type s_type;
835    unsigned z_shift = 0, z_width = 0, z_mask = 0;
836    LLVMValueRef z_dst = NULL;
837    LLVMValueRef stencil_vals = NULL;
838    LLVMValueRef z_bitmask = NULL, stencil_shift = NULL;
839    LLVMValueRef z_pass = NULL, s_pass_mask = NULL;
840    LLVMValueRef current_mask = lp_build_mask_value(mask);
841    LLVMValueRef front_facing = NULL;
842    boolean have_z, have_s;
843 
844    /*
845     * Depths are expected to be between 0 and 1, even if they are stored in
846     * floats. Setting these bits here will ensure that the lp_build_conv() call
847     * below won't try to unnecessarily clamp the incoming values.
848     */
849    if(z_src_type.floating) {
850       z_src_type.sign = FALSE;
851       z_src_type.norm = TRUE;
852    }
853    else {
854       assert(!z_src_type.sign);
855       assert(z_src_type.norm);
856    }
857 
858    /* Pick the type matching the depth-stencil format. */
859    z_type = lp_depth_type(format_desc, z_src_type.length);
860 
861    /* Pick the intermediate type for depth operations. */
862    z_type.width = z_src_type.width;
863    assert(z_type.length == z_src_type.length);
864 
865    /* FIXME: for non-float depth/stencil might generate better code
866     * if we'd always split it up to use 128bit operations.
867     * For stencil we'd almost certainly want to pack to 8xi16 values,
868     * for z just run twice.
869     */
870 
871    /* Sanity checking */
872    {
873       const unsigned z_swizzle = format_desc->swizzle[0];
874       const unsigned s_swizzle = format_desc->swizzle[1];
875 
876       assert(z_swizzle != PIPE_SWIZZLE_NONE ||
877              s_swizzle != PIPE_SWIZZLE_NONE);
878 
879       assert(depth->enabled || stencil[0].enabled);
880 
881       assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
882       assert(format_desc->block.width == 1);
883       assert(format_desc->block.height == 1);
884 
885       if (stencil[0].enabled) {
886          assert(s_swizzle < 4);
887          assert(format_desc->channel[s_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED);
888          assert(format_desc->channel[s_swizzle].pure_integer);
889          assert(!format_desc->channel[s_swizzle].normalized);
890          assert(format_desc->channel[s_swizzle].size == 8);
891       }
892 
893       if (depth->enabled) {
894          assert(z_swizzle < 4);
895          if (z_type.floating) {
896             assert(z_swizzle == 0);
897             assert(format_desc->channel[z_swizzle].type ==
898                    UTIL_FORMAT_TYPE_FLOAT);
899             assert(format_desc->channel[z_swizzle].size == 32);
900          }
901          else {
902             assert(format_desc->channel[z_swizzle].type ==
903                    UTIL_FORMAT_TYPE_UNSIGNED);
904             assert(format_desc->channel[z_swizzle].normalized);
905             assert(!z_type.fixed);
906          }
907       }
908    }
909 
910 
911    /* Setup build context for Z vals */
912    lp_build_context_init(&z_bld, gallivm, z_type);
913 
914    /* Setup build context for stencil vals */
915    s_type = lp_int_type(z_type);
916    lp_build_context_init(&s_bld, gallivm, s_type);
917 
918    /* Compute and apply the Z/stencil bitmasks and shifts.
919     */
920    {
921       unsigned s_shift, s_mask;
922 
923       z_dst = z_fb;
924       stencil_vals = s_fb;
925 
926       have_z = get_z_shift_and_mask(format_desc, &z_shift, &z_width, &z_mask);
927       have_s = get_s_shift_and_mask(format_desc, &s_shift, &s_mask);
928 
929       if (have_z) {
930          if (z_mask != 0xffffffff) {
931             z_bitmask = lp_build_const_int_vec(gallivm, z_type, z_mask);
932          }
933 
934          /*
935           * Align the framebuffer Z 's LSB to the right.
936           */
937          if (z_shift) {
938             LLVMValueRef shift = lp_build_const_int_vec(gallivm, z_type, z_shift);
939             z_dst = LLVMBuildLShr(builder, z_dst, shift, "z_dst");
940          } else if (z_bitmask) {
941             z_dst = LLVMBuildAnd(builder, z_dst, z_bitmask, "z_dst");
942          } else {
943             lp_build_name(z_dst, "z_dst");
944          }
945       }
946 
947       if (have_s) {
948          if (s_shift) {
949             LLVMValueRef shift = lp_build_const_int_vec(gallivm, s_type, s_shift);
950             stencil_vals = LLVMBuildLShr(builder, stencil_vals, shift, "");
951             stencil_shift = shift;  /* used below */
952          }
953 
954          if (s_mask != 0xffffffff) {
955             LLVMValueRef mask = lp_build_const_int_vec(gallivm, s_type, s_mask);
956             stencil_vals = LLVMBuildAnd(builder, stencil_vals, mask, "");
957          }
958 
959          lp_build_name(stencil_vals, "s_dst");
960       }
961    }
962 
963    if (stencil[0].enabled) {
964 
965       if (face) {
966          if (0) {
967             /*
968              * XXX: the scalar expansion below produces atrocious code
969              * (basically producing a 64bit scalar value, then moving the 2
970              * 32bit pieces separately to simd, plus 4 shuffles, which is
971              * seriously lame). But the scalar-simd transitions are always
972              * tricky, so no big surprise there.
973              * This here would be way better, however llvm has some serious
974              * trouble later using it in the select, probably because it will
975              * recognize the expression as constant and move the simd value
976              * away (out of the loop) - and then it will suddenly try
977              * constructing i1 high-bit masks out of it later...
978              * (Try piglit stencil-twoside.)
979              * Note this is NOT due to using SExt/Trunc, it fails exactly the
980              * same even when using native compare/select.
981              * I cannot reproduce this problem when using stand-alone compiler
982              * though, suggesting some problem with optimization passes...
983              * (With stand-alone compilation, the construction of this mask
984              * value, no matter if the easy 3 instruction here or the complex
985              * 16+ one below, never gets separated from where it's used.)
986              * The scalar code still has the same problem, but the generated
987              * code looks a bit better at least for some reason, even if
988              * mostly by luck (the fundamental issue clearly is the same).
989              */
990             front_facing = lp_build_broadcast(gallivm, s_bld.vec_type, face);
991             /* front_facing = face != 0 ? ~0 : 0 */
992             front_facing = lp_build_compare(gallivm, s_bld.type,
993                                             PIPE_FUNC_NOTEQUAL,
994                                             front_facing, s_bld.zero);
995          } else {
996             LLVMValueRef zero = lp_build_const_int32(gallivm, 0);
997 
998             /* front_facing = face != 0 ? ~0 : 0 */
999             front_facing = LLVMBuildICmp(builder, LLVMIntNE, face, zero, "");
1000             front_facing = LLVMBuildSExt(builder, front_facing,
1001                                          LLVMIntTypeInContext(gallivm->context,
1002                                                 s_bld.type.length*s_bld.type.width),
1003                                          "");
1004             front_facing = LLVMBuildBitCast(builder, front_facing,
1005                                             s_bld.int_vec_type, "");
1006 
1007          }
1008       }
1009 
1010       s_pass_mask = lp_build_stencil_test(&s_bld, stencil,
1011                                           stencil_refs, stencil_vals,
1012                                           front_facing);
1013 
1014       /* apply stencil-fail operator */
1015       {
1016          LLVMValueRef s_fail_mask = lp_build_andnot(&s_bld, current_mask, s_pass_mask);
1017          stencil_vals = lp_build_stencil_op(&s_bld, stencil, S_FAIL_OP,
1018                                             stencil_refs, stencil_vals,
1019                                             s_fail_mask, front_facing);
1020       }
1021    }
1022 
1023    if (depth->enabled) {
1024       /*
1025        * Convert fragment Z to the desired type, aligning the LSB to the right.
1026        */
1027 
1028       assert(z_type.width == z_src_type.width);
1029       assert(z_type.length == z_src_type.length);
1030       assert(lp_check_value(z_src_type, z_src));
1031       if (z_src_type.floating) {
1032          /*
1033           * Convert from floating point values
1034           */
1035 
1036          if (!z_type.floating) {
1037             z_src = lp_build_clamped_float_to_unsigned_norm(gallivm,
1038                                                             z_src_type,
1039                                                             z_width,
1040                                                             z_src);
1041          }
1042       } else {
1043          /*
1044           * Convert from unsigned normalized values.
1045           */
1046 
1047          assert(!z_src_type.sign);
1048          assert(!z_src_type.fixed);
1049          assert(z_src_type.norm);
1050          assert(!z_type.floating);
1051          if (z_src_type.width > z_width) {
1052             LLVMValueRef shift = lp_build_const_int_vec(gallivm, z_src_type,
1053                                                         z_src_type.width - z_width);
1054             z_src = LLVMBuildLShr(builder, z_src, shift, "");
1055          }
1056       }
1057       assert(lp_check_value(z_type, z_src));
1058 
1059       lp_build_name(z_src, "z_src");
1060 
1061       /* compare src Z to dst Z, returning 'pass' mask */
1062       z_pass = lp_build_cmp(&z_bld, depth->func, z_src, z_dst);
1063 
1064       /* mask off bits that failed stencil test */
1065       if (s_pass_mask) {
1066          current_mask = LLVMBuildAnd(builder, current_mask, s_pass_mask, "");
1067       }
1068 
1069       if (!stencil[0].enabled) {
1070          /* We can potentially skip all remaining operations here, but only
1071           * if stencil is disabled because we still need to update the stencil
1072           * buffer values.  Don't need to update Z buffer values.
1073           */
1074          lp_build_mask_update(mask, z_pass);
1075 
1076          if (do_branch) {
1077             lp_build_mask_check(mask);
1078          }
1079       }
1080 
1081       if (depth->writemask) {
1082          LLVMValueRef z_pass_mask;
1083 
1084          /* mask off bits that failed Z test */
1085          z_pass_mask = LLVMBuildAnd(builder, current_mask, z_pass, "");
1086 
1087          /* Mix the old and new Z buffer values.
1088           * z_dst[i] = zselectmask[i] ? z_src[i] : z_dst[i]
1089           */
1090          z_dst = lp_build_select(&z_bld, z_pass_mask, z_src, z_dst);
1091       }
1092 
1093       if (stencil[0].enabled) {
1094          /* update stencil buffer values according to z pass/fail result */
1095          LLVMValueRef z_fail_mask, z_pass_mask;
1096 
1097          /* apply Z-fail operator */
1098          z_fail_mask = lp_build_andnot(&s_bld, current_mask, z_pass);
1099          stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_FAIL_OP,
1100                                             stencil_refs, stencil_vals,
1101                                             z_fail_mask, front_facing);
1102 
1103          /* apply Z-pass operator */
1104          z_pass_mask = LLVMBuildAnd(builder, current_mask, z_pass, "");
1105          stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_PASS_OP,
1106                                             stencil_refs, stencil_vals,
1107                                             z_pass_mask, front_facing);
1108       }
1109    }
1110    else {
1111       /* No depth test: apply Z-pass operator to stencil buffer values which
1112        * passed the stencil test.
1113        */
1114       s_pass_mask = LLVMBuildAnd(builder, current_mask, s_pass_mask, "");
1115       stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_PASS_OP,
1116                                          stencil_refs, stencil_vals,
1117                                          s_pass_mask, front_facing);
1118    }
1119 
1120    /* Put Z and stencil bits in the right place */
1121    if (have_z && z_shift) {
1122       LLVMValueRef shift = lp_build_const_int_vec(gallivm, z_type, z_shift);
1123       z_dst = LLVMBuildShl(builder, z_dst, shift, "");
1124    }
1125    if (stencil_vals && stencil_shift)
1126       stencil_vals = LLVMBuildShl(builder, stencil_vals,
1127                                   stencil_shift, "");
1128 
1129    /* Finally, merge the z/stencil values */
1130    if (format_desc->block.bits <= 32) {
1131       if (have_z && have_s)
1132          *z_value = LLVMBuildOr(builder, z_dst, stencil_vals, "");
1133       else if (have_z)
1134          *z_value = z_dst;
1135       else
1136          *z_value = stencil_vals;
1137       *s_value = *z_value;
1138    }
1139    else {
1140       *z_value = z_dst;
1141       *s_value = stencil_vals;
1142    }
1143 
1144    if (s_pass_mask)
1145       lp_build_mask_update(mask, s_pass_mask);
1146 
1147    if (depth->enabled && stencil[0].enabled)
1148       lp_build_mask_update(mask, z_pass);
1149 }
1150 
1151