nir_range_analysis.c revision 7ec681f3
1/*
2 * Copyright © 2018 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23#include <math.h>
24#include <float.h>
25#include "nir.h"
26#include "nir_range_analysis.h"
27#include "util/hash_table.h"
28
29/**
30 * Analyzes a sequence of operations to determine some aspects of the range of
31 * the result.
32 */
33
34static bool
35is_not_negative(enum ssa_ranges r)
36{
37   return r == gt_zero || r == ge_zero || r == eq_zero;
38}
39
40static bool
41is_not_zero(enum ssa_ranges r)
42{
43   return r == gt_zero || r == lt_zero || r == ne_zero;
44}
45
46static void *
47pack_data(const struct ssa_result_range r)
48{
49   return (void *)(uintptr_t)(r.range | r.is_integral << 8 | r.is_finite << 9 |
50                              r.is_a_number << 10);
51}
52
53static struct ssa_result_range
54unpack_data(const void *p)
55{
56   const uintptr_t v = (uintptr_t) p;
57
58   return (struct ssa_result_range){
59      .range       = v & 0xff,
60      .is_integral = (v & 0x00100) != 0,
61      .is_finite   = (v & 0x00200) != 0,
62      .is_a_number = (v & 0x00400) != 0
63   };
64}
65
66static void *
67pack_key(const struct nir_alu_instr *instr, nir_alu_type type)
68{
69   uintptr_t type_encoding;
70   uintptr_t ptr = (uintptr_t) instr;
71
72   /* The low 2 bits have to be zero or this whole scheme falls apart. */
73   assert((ptr & 0x3) == 0);
74
75   /* NIR is typeless in the sense that sequences of bits have whatever
76    * meaning is attached to them by the instruction that consumes them.
77    * However, the number of bits must match between producer and consumer.
78    * As a result, the number of bits does not need to be encoded here.
79    */
80   switch (nir_alu_type_get_base_type(type)) {
81   case nir_type_int:   type_encoding = 0; break;
82   case nir_type_uint:  type_encoding = 1; break;
83   case nir_type_bool:  type_encoding = 2; break;
84   case nir_type_float: type_encoding = 3; break;
85   default: unreachable("Invalid base type.");
86   }
87
88   return (void *)(ptr | type_encoding);
89}
90
91static nir_alu_type
92nir_alu_src_type(const nir_alu_instr *instr, unsigned src)
93{
94   return nir_alu_type_get_base_type(nir_op_infos[instr->op].input_types[src]) |
95          nir_src_bit_size(instr->src[src].src);
96}
97
98static struct ssa_result_range
99analyze_constant(const struct nir_alu_instr *instr, unsigned src,
100                 nir_alu_type use_type)
101{
102   uint8_t swizzle[NIR_MAX_VEC_COMPONENTS] = { 0, 1, 2, 3,
103                                               4, 5, 6, 7,
104                                               8, 9, 10, 11,
105                                               12, 13, 14, 15 };
106
107   /* If the source is an explicitly sized source, then we need to reset
108    * both the number of components and the swizzle.
109    */
110   const unsigned num_components = nir_ssa_alu_instr_src_components(instr, src);
111
112   for (unsigned i = 0; i < num_components; ++i)
113      swizzle[i] = instr->src[src].swizzle[i];
114
115   const nir_load_const_instr *const load =
116      nir_instr_as_load_const(instr->src[src].src.ssa->parent_instr);
117
118   struct ssa_result_range r = { unknown, false, false, false };
119
120   switch (nir_alu_type_get_base_type(use_type)) {
121   case nir_type_float: {
122      double min_value = DBL_MAX;
123      double max_value = -DBL_MAX;
124      bool any_zero = false;
125      bool all_zero = true;
126
127      r.is_integral = true;
128      r.is_a_number = true;
129      r.is_finite = true;
130
131      for (unsigned i = 0; i < num_components; ++i) {
132         const double v = nir_const_value_as_float(load->value[swizzle[i]],
133                                                   load->def.bit_size);
134
135         if (floor(v) != v)
136            r.is_integral = false;
137
138         if (isnan(v))
139            r.is_a_number = false;
140
141         if (!isfinite(v))
142            r.is_finite = false;
143
144         any_zero = any_zero || (v == 0.0);
145         all_zero = all_zero && (v == 0.0);
146         min_value = MIN2(min_value, v);
147         max_value = MAX2(max_value, v);
148      }
149
150      assert(any_zero >= all_zero);
151      assert(isnan(max_value) || max_value >= min_value);
152
153      if (all_zero)
154         r.range = eq_zero;
155      else if (min_value > 0.0)
156         r.range = gt_zero;
157      else if (min_value == 0.0)
158         r.range = ge_zero;
159      else if (max_value < 0.0)
160         r.range = lt_zero;
161      else if (max_value == 0.0)
162         r.range = le_zero;
163      else if (!any_zero)
164         r.range = ne_zero;
165      else
166         r.range = unknown;
167
168      return r;
169   }
170
171   case nir_type_int:
172   case nir_type_bool: {
173      int64_t min_value = INT_MAX;
174      int64_t max_value = INT_MIN;
175      bool any_zero = false;
176      bool all_zero = true;
177
178      for (unsigned i = 0; i < num_components; ++i) {
179         const int64_t v = nir_const_value_as_int(load->value[swizzle[i]],
180                                                  load->def.bit_size);
181
182         any_zero = any_zero || (v == 0);
183         all_zero = all_zero && (v == 0);
184         min_value = MIN2(min_value, v);
185         max_value = MAX2(max_value, v);
186      }
187
188      assert(any_zero >= all_zero);
189      assert(max_value >= min_value);
190
191      if (all_zero)
192         r.range = eq_zero;
193      else if (min_value > 0)
194         r.range = gt_zero;
195      else if (min_value == 0)
196         r.range = ge_zero;
197      else if (max_value < 0)
198         r.range = lt_zero;
199      else if (max_value == 0)
200         r.range = le_zero;
201      else if (!any_zero)
202         r.range = ne_zero;
203      else
204         r.range = unknown;
205
206      return r;
207   }
208
209   case nir_type_uint: {
210      bool any_zero = false;
211      bool all_zero = true;
212
213      for (unsigned i = 0; i < num_components; ++i) {
214         const uint64_t v = nir_const_value_as_uint(load->value[swizzle[i]],
215                                                    load->def.bit_size);
216
217         any_zero = any_zero || (v == 0);
218         all_zero = all_zero && (v == 0);
219      }
220
221      assert(any_zero >= all_zero);
222
223      if (all_zero)
224         r.range = eq_zero;
225      else if (any_zero)
226         r.range = ge_zero;
227      else
228         r.range = gt_zero;
229
230      return r;
231   }
232
233   default:
234      unreachable("Invalid alu source type");
235   }
236}
237
238/**
239 * Short-hand name for use in the tables in analyze_expression.  If this name
240 * becomes a problem on some compiler, we can change it to _.
241 */
242#define _______ unknown
243
244
245#if defined(__clang__)
246   /* clang wants _Pragma("unroll X") */
247   #define pragma_unroll_5 _Pragma("unroll 5")
248   #define pragma_unroll_7 _Pragma("unroll 7")
249/* gcc wants _Pragma("GCC unroll X") */
250#elif defined(__GNUC__)
251   #if __GNUC__ >= 8
252      #define pragma_unroll_5 _Pragma("GCC unroll 5")
253      #define pragma_unroll_7 _Pragma("GCC unroll 7")
254   #else
255      #pragma GCC optimize ("unroll-loops")
256      #define pragma_unroll_5
257      #define pragma_unroll_7
258   #endif
259#else
260   /* MSVC doesn't have C99's _Pragma() */
261   #define pragma_unroll_5
262   #define pragma_unroll_7
263#endif
264
265
266#ifndef NDEBUG
267#define ASSERT_TABLE_IS_COMMUTATIVE(t)                        \
268   do {                                                       \
269      static bool first = true;                               \
270      if (first) {                                            \
271         first = false;                                       \
272         pragma_unroll_7                                      \
273         for (unsigned r = 0; r < ARRAY_SIZE(t); r++) {       \
274            pragma_unroll_7                                   \
275            for (unsigned c = 0; c < ARRAY_SIZE(t[0]); c++)   \
276               assert(t[r][c] == t[c][r]);                    \
277         }                                                    \
278      }                                                       \
279   } while (false)
280
281#define ASSERT_TABLE_IS_DIAGONAL(t)                           \
282   do {                                                       \
283      static bool first = true;                               \
284      if (first) {                                            \
285         first = false;                                       \
286         pragma_unroll_7                                      \
287         for (unsigned r = 0; r < ARRAY_SIZE(t); r++)         \
288            assert(t[r][r] == r);                             \
289      }                                                       \
290   } while (false)
291
292#else
293#define ASSERT_TABLE_IS_COMMUTATIVE(t)
294#define ASSERT_TABLE_IS_DIAGONAL(t)
295#endif /* !defined(NDEBUG) */
296
297static enum ssa_ranges
298union_ranges(enum ssa_ranges a, enum ssa_ranges b)
299{
300   static const enum ssa_ranges union_table[last_range + 1][last_range + 1] = {
301      /* left\right   unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
302      /* unknown */ { _______, _______, _______, _______, _______, _______, _______ },
303      /* lt_zero */ { _______, lt_zero, le_zero, ne_zero, _______, ne_zero, le_zero },
304      /* le_zero */ { _______, le_zero, le_zero, _______, _______, _______, le_zero },
305      /* gt_zero */ { _______, ne_zero, _______, gt_zero, ge_zero, ne_zero, ge_zero },
306      /* ge_zero */ { _______, _______, _______, ge_zero, ge_zero, _______, ge_zero },
307      /* ne_zero */ { _______, ne_zero, _______, ne_zero, _______, ne_zero, _______ },
308      /* eq_zero */ { _______, le_zero, le_zero, ge_zero, ge_zero, _______, eq_zero },
309   };
310
311   ASSERT_TABLE_IS_COMMUTATIVE(union_table);
312   ASSERT_TABLE_IS_DIAGONAL(union_table);
313
314   return union_table[a][b];
315}
316
317#ifndef NDEBUG
318/* Verify that the 'unknown' entry in each row (or column) of the table is the
319 * union of all the other values in the row (or column).
320 */
321#define ASSERT_UNION_OF_OTHERS_MATCHES_UNKNOWN_2_SOURCE(t)              \
322   do {                                                                 \
323      static bool first = true;                                         \
324      if (first) {                                                      \
325         first = false;                                                 \
326         pragma_unroll_7                                                \
327         for (unsigned i = 0; i < last_range; i++) {                    \
328            enum ssa_ranges col_range = t[i][unknown + 1];              \
329            enum ssa_ranges row_range = t[unknown + 1][i];              \
330                                                                        \
331            pragma_unroll_5                                             \
332            for (unsigned j = unknown + 2; j < last_range; j++) {       \
333               col_range = union_ranges(col_range, t[i][j]);            \
334               row_range = union_ranges(row_range, t[j][i]);            \
335            }                                                           \
336                                                                        \
337            assert(col_range == t[i][unknown]);                         \
338            assert(row_range == t[unknown][i]);                         \
339         }                                                              \
340      }                                                                 \
341   } while (false)
342
343/* For most operations, the union of ranges for a strict inequality and
344 * equality should be the range of the non-strict inequality (e.g.,
345 * union_ranges(range(op(lt_zero), range(op(eq_zero))) == range(op(le_zero)).
346 *
347 * Does not apply to selection-like opcodes (bcsel, fmin, fmax, etc.).
348 */
349#define ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_1_SOURCE(t) \
350   do {                                                                 \
351      assert(union_ranges(t[lt_zero], t[eq_zero]) == t[le_zero]);       \
352      assert(union_ranges(t[gt_zero], t[eq_zero]) == t[ge_zero]);       \
353   } while (false)
354
355#define ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_2_SOURCE(t) \
356   do {                                                                 \
357      static bool first = true;                                         \
358      if (first) {                                                      \
359         first = false;                                                 \
360         pragma_unroll_7                                                \
361         for (unsigned i = 0; i < last_range; i++) {                    \
362            assert(union_ranges(t[i][lt_zero], t[i][eq_zero]) == t[i][le_zero]); \
363            assert(union_ranges(t[i][gt_zero], t[i][eq_zero]) == t[i][ge_zero]); \
364            assert(union_ranges(t[lt_zero][i], t[eq_zero][i]) == t[le_zero][i]); \
365            assert(union_ranges(t[gt_zero][i], t[eq_zero][i]) == t[ge_zero][i]); \
366         }                                                              \
367      }                                                                 \
368   } while (false)
369
370/* Several other unordered tuples span the range of "everything."  Each should
371 * have the same value as unknown: (lt_zero, ge_zero), (le_zero, gt_zero), and
372 * (eq_zero, ne_zero).  union_ranges is already commutative, so only one
373 * ordering needs to be checked.
374 *
375 * Does not apply to selection-like opcodes (bcsel, fmin, fmax, etc.).
376 *
377 * In cases where this can be used, it is unnecessary to also use
378 * ASSERT_UNION_OF_OTHERS_MATCHES_UNKNOWN_*_SOURCE.  For any range X,
379 * union_ranges(X, X) == X.  The disjoint ranges cover all of the non-unknown
380 * possibilities, so the union of all the unions of disjoint ranges is
381 * equivalent to the union of "others."
382 */
383#define ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_1_SOURCE(t)            \
384   do {                                                                 \
385      assert(union_ranges(t[lt_zero], t[ge_zero]) == t[unknown]);       \
386      assert(union_ranges(t[le_zero], t[gt_zero]) == t[unknown]);       \
387      assert(union_ranges(t[eq_zero], t[ne_zero]) == t[unknown]);       \
388   } while (false)
389
390#define ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_2_SOURCE(t)            \
391   do {                                                                 \
392      static bool first = true;                                         \
393      if (first) {                                                      \
394         first = false;                                                 \
395         pragma_unroll_7                                                \
396         for (unsigned i = 0; i < last_range; i++) {                    \
397            assert(union_ranges(t[i][lt_zero], t[i][ge_zero]) ==        \
398                   t[i][unknown]);                                      \
399            assert(union_ranges(t[i][le_zero], t[i][gt_zero]) ==        \
400                   t[i][unknown]);                                      \
401            assert(union_ranges(t[i][eq_zero], t[i][ne_zero]) ==        \
402                   t[i][unknown]);                                      \
403                                                                        \
404            assert(union_ranges(t[lt_zero][i], t[ge_zero][i]) ==        \
405                   t[unknown][i]);                                      \
406            assert(union_ranges(t[le_zero][i], t[gt_zero][i]) ==        \
407                   t[unknown][i]);                                      \
408            assert(union_ranges(t[eq_zero][i], t[ne_zero][i]) ==        \
409                   t[unknown][i]);                                      \
410         }                                                              \
411      }                                                                 \
412   } while (false)
413
414#else
415#define ASSERT_UNION_OF_OTHERS_MATCHES_UNKNOWN_2_SOURCE(t)
416#define ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_1_SOURCE(t)
417#define ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_2_SOURCE(t)
418#define ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_1_SOURCE(t)
419#define ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_2_SOURCE(t)
420#endif /* !defined(NDEBUG) */
421
422/**
423 * Analyze an expression to determine the range of its result
424 *
425 * The end result of this analysis is a token that communicates something
426 * about the range of values.  There's an implicit grammar that produces
427 * tokens from sequences of literal values, other tokens, and operations.
428 * This function implements this grammar as a recursive-descent parser.  Some
429 * (but not all) of the grammar is listed in-line in the function.
430 */
431static struct ssa_result_range
432analyze_expression(const nir_alu_instr *instr, unsigned src,
433                   struct hash_table *ht, nir_alu_type use_type)
434{
435   /* Ensure that the _Pragma("GCC unroll 7") above are correct. */
436   STATIC_ASSERT(last_range + 1 == 7);
437
438   if (!instr->src[src].src.is_ssa)
439      return (struct ssa_result_range){unknown, false, false, false};
440
441   if (nir_src_is_const(instr->src[src].src))
442      return analyze_constant(instr, src, use_type);
443
444   if (instr->src[src].src.ssa->parent_instr->type != nir_instr_type_alu)
445      return (struct ssa_result_range){unknown, false, false, false};
446
447   const struct nir_alu_instr *const alu =
448       nir_instr_as_alu(instr->src[src].src.ssa->parent_instr);
449
450   /* Bail if the type of the instruction generating the value does not match
451    * the type the value will be interpreted as.  int/uint/bool can be
452    * reinterpreted trivially.  The most important cases are between float and
453    * non-float.
454    */
455   if (alu->op != nir_op_mov && alu->op != nir_op_bcsel) {
456      const nir_alu_type use_base_type =
457         nir_alu_type_get_base_type(use_type);
458      const nir_alu_type src_base_type =
459         nir_alu_type_get_base_type(nir_op_infos[alu->op].output_type);
460
461      if (use_base_type != src_base_type &&
462          (use_base_type == nir_type_float ||
463           src_base_type == nir_type_float)) {
464         return (struct ssa_result_range){unknown, false, false, false};
465      }
466   }
467
468   struct hash_entry *he = _mesa_hash_table_search(ht, pack_key(alu, use_type));
469   if (he != NULL)
470      return unpack_data(he->data);
471
472   struct ssa_result_range r = {unknown, false, false, false};
473
474   /* ge_zero: ge_zero + ge_zero
475    *
476    * gt_zero: gt_zero + eq_zero
477    *        | gt_zero + ge_zero
478    *        | eq_zero + gt_zero   # Addition is commutative
479    *        | ge_zero + gt_zero   # Addition is commutative
480    *        | gt_zero + gt_zero
481    *        ;
482    *
483    * le_zero: le_zero + le_zero
484    *
485    * lt_zero: lt_zero + eq_zero
486    *        | lt_zero + le_zero
487    *        | eq_zero + lt_zero   # Addition is commutative
488    *        | le_zero + lt_zero   # Addition is commutative
489    *        | lt_zero + lt_zero
490    *        ;
491    *
492    * ne_zero: eq_zero + ne_zero
493    *        | ne_zero + eq_zero   # Addition is commutative
494    *        ;
495    *
496    * eq_zero: eq_zero + eq_zero
497    *        ;
498    *
499    * All other cases are 'unknown'.  The seeming odd entry is (ne_zero,
500    * ne_zero), but that could be (-5, +5) which is not ne_zero.
501    */
502   static const enum ssa_ranges fadd_table[last_range + 1][last_range + 1] = {
503      /* left\right   unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
504      /* unknown */ { _______, _______, _______, _______, _______, _______, _______ },
505      /* lt_zero */ { _______, lt_zero, lt_zero, _______, _______, _______, lt_zero },
506      /* le_zero */ { _______, lt_zero, le_zero, _______, _______, _______, le_zero },
507      /* gt_zero */ { _______, _______, _______, gt_zero, gt_zero, _______, gt_zero },
508      /* ge_zero */ { _______, _______, _______, gt_zero, ge_zero, _______, ge_zero },
509      /* ne_zero */ { _______, _______, _______, _______, _______, _______, ne_zero },
510      /* eq_zero */ { _______, lt_zero, le_zero, gt_zero, ge_zero, ne_zero, eq_zero },
511   };
512
513   ASSERT_TABLE_IS_COMMUTATIVE(fadd_table);
514   ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_2_SOURCE(fadd_table);
515   ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_2_SOURCE(fadd_table);
516
517   /* Due to flush-to-zero semanatics of floating-point numbers with very
518    * small mangnitudes, we can never really be sure a result will be
519    * non-zero.
520    *
521    * ge_zero: ge_zero * ge_zero
522    *        | ge_zero * gt_zero
523    *        | ge_zero * eq_zero
524    *        | le_zero * lt_zero
525    *        | lt_zero * le_zero  # Multiplication is commutative
526    *        | le_zero * le_zero
527    *        | gt_zero * ge_zero  # Multiplication is commutative
528    *        | eq_zero * ge_zero  # Multiplication is commutative
529    *        | a * a              # Left source == right source
530    *        | gt_zero * gt_zero
531    *        | lt_zero * lt_zero
532    *        ;
533    *
534    * le_zero: ge_zero * le_zero
535    *        | ge_zero * lt_zero
536    *        | lt_zero * ge_zero  # Multiplication is commutative
537    *        | le_zero * ge_zero  # Multiplication is commutative
538    *        | le_zero * gt_zero
539    *        | lt_zero * gt_zero
540    *        | gt_zero * lt_zero  # Multiplication is commutative
541    *        ;
542    *
543    * eq_zero: eq_zero * <any>
544    *          <any> * eq_zero    # Multiplication is commutative
545    *
546    * All other cases are 'unknown'.
547    */
548   static const enum ssa_ranges fmul_table[last_range + 1][last_range + 1] = {
549      /* left\right   unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
550      /* unknown */ { _______, _______, _______, _______, _______, _______, eq_zero },
551      /* lt_zero */ { _______, ge_zero, ge_zero, le_zero, le_zero, _______, eq_zero },
552      /* le_zero */ { _______, ge_zero, ge_zero, le_zero, le_zero, _______, eq_zero },
553      /* gt_zero */ { _______, le_zero, le_zero, ge_zero, ge_zero, _______, eq_zero },
554      /* ge_zero */ { _______, le_zero, le_zero, ge_zero, ge_zero, _______, eq_zero },
555      /* ne_zero */ { _______, _______, _______, _______, _______, _______, eq_zero },
556      /* eq_zero */ { eq_zero, eq_zero, eq_zero, eq_zero, eq_zero, eq_zero, eq_zero }
557   };
558
559   ASSERT_TABLE_IS_COMMUTATIVE(fmul_table);
560   ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_2_SOURCE(fmul_table);
561   ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_2_SOURCE(fmul_table);
562
563   static const enum ssa_ranges fneg_table[last_range + 1] = {
564   /* unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
565      _______, gt_zero, ge_zero, lt_zero, le_zero, ne_zero, eq_zero
566   };
567
568   ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_1_SOURCE(fneg_table);
569   ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_1_SOURCE(fneg_table);
570
571
572   switch (alu->op) {
573   case nir_op_b2f32:
574   case nir_op_b2i32:
575      /* b2f32 will generate either 0.0 or 1.0.  This case is trivial.
576       *
577       * b2i32 will generate either 0x00000000 or 0x00000001.  When those bit
578       * patterns are interpreted as floating point, they are 0.0 and
579       * 1.401298464324817e-45.  The latter is subnormal, but it is finite and
580       * a number.
581       */
582      r = (struct ssa_result_range){ge_zero, alu->op == nir_op_b2f32, true, true};
583      break;
584
585   case nir_op_bcsel: {
586      const struct ssa_result_range left =
587         analyze_expression(alu, 1, ht, use_type);
588      const struct ssa_result_range right =
589         analyze_expression(alu, 2, ht, use_type);
590
591      r.is_integral = left.is_integral && right.is_integral;
592
593      /* This could be better, but it would require a lot of work.  For
594       * example, the result of the following is a number:
595       *
596       *    bcsel(a > 0.0, a, 38.6)
597       *
598       * If the result of 'a > 0.0' is true, then the use of 'a' in the true
599       * part of the bcsel must be a number.
600       *
601       * Other cases are even more challenging.
602       *
603       *    bcsel(a > 0.5, a - 0.5, 0.0)
604       */
605      r.is_a_number = left.is_a_number && right.is_a_number;
606      r.is_finite = left.is_finite && right.is_finite;
607
608      r.range = union_ranges(left.range, right.range);
609      break;
610   }
611
612   case nir_op_i2f32:
613   case nir_op_u2f32:
614      r = analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
615
616      r.is_integral = true;
617      r.is_a_number = true;
618      r.is_finite = true;
619
620      if (r.range == unknown && alu->op == nir_op_u2f32)
621         r.range = ge_zero;
622
623      break;
624
625   case nir_op_fabs:
626      r = analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
627
628      switch (r.range) {
629      case unknown:
630      case le_zero:
631      case ge_zero:
632         r.range = ge_zero;
633         break;
634
635      case lt_zero:
636      case gt_zero:
637      case ne_zero:
638         r.range = gt_zero;
639         break;
640
641      case eq_zero:
642         break;
643      }
644
645      break;
646
647   case nir_op_fadd: {
648      const struct ssa_result_range left =
649         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
650      const struct ssa_result_range right =
651         analyze_expression(alu, 1, ht, nir_alu_src_type(alu, 1));
652
653      r.is_integral = left.is_integral && right.is_integral;
654      r.range = fadd_table[left.range][right.range];
655
656      /* X + Y is NaN if either operand is NaN or if one operand is +Inf and
657       * the other is -Inf.  If neither operand is NaN and at least one of the
658       * operands is finite, then the result cannot be NaN.
659       */
660      r.is_a_number = left.is_a_number && right.is_a_number &&
661         (left.is_finite || right.is_finite);
662      break;
663   }
664
665   case nir_op_fexp2: {
666      /* If the parameter might be less than zero, the mathematically result
667       * will be on (0, 1).  For sufficiently large magnitude negative
668       * parameters, the result will flush to zero.
669       */
670      static const enum ssa_ranges table[last_range + 1] = {
671      /* unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
672         ge_zero, ge_zero, ge_zero, gt_zero, gt_zero, ge_zero, gt_zero
673      };
674
675      r = analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
676
677      ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_1_SOURCE(table);
678      ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_1_SOURCE(table);
679
680      r.is_integral = r.is_integral && is_not_negative(r.range);
681      r.range = table[r.range];
682
683      /* Various cases can result in NaN, so assume the worst. */
684      r.is_finite = false;
685      r.is_a_number = false;
686      break;
687   }
688
689   case nir_op_fmax: {
690      const struct ssa_result_range left =
691         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
692      const struct ssa_result_range right =
693         analyze_expression(alu, 1, ht, nir_alu_src_type(alu, 1));
694
695      r.is_integral = left.is_integral && right.is_integral;
696
697      /* This is conservative.  It may be possible to determine that the
698       * result must be finite in more cases, but it would take some effort to
699       * work out all the corners.  For example, fmax({lt_zero, finite},
700       * {lt_zero}) should result in {lt_zero, finite}.
701       */
702      r.is_finite = left.is_finite && right.is_finite;
703
704      /* If one source is NaN, fmax always picks the other source. */
705      r.is_a_number = left.is_a_number || right.is_a_number;
706
707      /* gt_zero: fmax(gt_zero, *)
708       *        | fmax(*, gt_zero)        # Treat fmax as commutative
709       *        ;
710       *
711       * ge_zero: fmax(ge_zero, ne_zero)
712       *        | fmax(ge_zero, lt_zero)
713       *        | fmax(ge_zero, le_zero)
714       *        | fmax(ge_zero, eq_zero)
715       *        | fmax(ne_zero, ge_zero)  # Treat fmax as commutative
716       *        | fmax(lt_zero, ge_zero)  # Treat fmax as commutative
717       *        | fmax(le_zero, ge_zero)  # Treat fmax as commutative
718       *        | fmax(eq_zero, ge_zero)  # Treat fmax as commutative
719       *        | fmax(ge_zero, ge_zero)
720       *        ;
721       *
722       * le_zero: fmax(le_zero, lt_zero)
723       *        | fmax(lt_zero, le_zero)  # Treat fmax as commutative
724       *        | fmax(le_zero, le_zero)
725       *        ;
726       *
727       * lt_zero: fmax(lt_zero, lt_zero)
728       *        ;
729       *
730       * ne_zero: fmax(ne_zero, lt_zero)
731       *        | fmax(lt_zero, ne_zero)  # Treat fmax as commutative
732       *        | fmax(ne_zero, ne_zero)
733       *        ;
734       *
735       * eq_zero: fmax(eq_zero, le_zero)
736       *        | fmax(eq_zero, lt_zero)
737       *        | fmax(le_zero, eq_zero)  # Treat fmax as commutative
738       *        | fmax(lt_zero, eq_zero)  # Treat fmax as commutative
739       *        | fmax(eq_zero, eq_zero)
740       *        ;
741       *
742       * All other cases are 'unknown'.
743       */
744      static const enum ssa_ranges table[last_range + 1][last_range + 1] = {
745         /* left\right   unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
746         /* unknown */ { _______, _______, _______, gt_zero, ge_zero, _______, _______ },
747         /* lt_zero */ { _______, lt_zero, le_zero, gt_zero, ge_zero, ne_zero, eq_zero },
748         /* le_zero */ { _______, le_zero, le_zero, gt_zero, ge_zero, _______, eq_zero },
749         /* gt_zero */ { gt_zero, gt_zero, gt_zero, gt_zero, gt_zero, gt_zero, gt_zero },
750         /* ge_zero */ { ge_zero, ge_zero, ge_zero, gt_zero, ge_zero, ge_zero, ge_zero },
751         /* ne_zero */ { _______, ne_zero, _______, gt_zero, ge_zero, ne_zero, _______ },
752         /* eq_zero */ { _______, eq_zero, eq_zero, gt_zero, ge_zero, _______, eq_zero }
753      };
754
755      /* Treat fmax as commutative. */
756      ASSERT_TABLE_IS_COMMUTATIVE(table);
757      ASSERT_TABLE_IS_DIAGONAL(table);
758      ASSERT_UNION_OF_OTHERS_MATCHES_UNKNOWN_2_SOURCE(table);
759
760      r.range = table[left.range][right.range];
761
762      /* Recall that when either value is NaN, fmax will pick the other value.
763       * This means the result range of the fmax will either be the "ideal"
764       * result range (calculated above) or the range of the non-NaN value.
765       */
766      if (!left.is_a_number)
767         r.range = union_ranges(r.range, right.range);
768
769      if (!right.is_a_number)
770         r.range = union_ranges(r.range, left.range);
771
772      break;
773   }
774
775   case nir_op_fmin: {
776      const struct ssa_result_range left =
777         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
778      const struct ssa_result_range right =
779         analyze_expression(alu, 1, ht, nir_alu_src_type(alu, 1));
780
781      r.is_integral = left.is_integral && right.is_integral;
782
783      /* This is conservative.  It may be possible to determine that the
784       * result must be finite in more cases, but it would take some effort to
785       * work out all the corners.  For example, fmin({gt_zero, finite},
786       * {gt_zero}) should result in {gt_zero, finite}.
787       */
788      r.is_finite = left.is_finite && right.is_finite;
789
790      /* If one source is NaN, fmin always picks the other source. */
791      r.is_a_number = left.is_a_number || right.is_a_number;
792
793      /* lt_zero: fmin(lt_zero, *)
794       *        | fmin(*, lt_zero)        # Treat fmin as commutative
795       *        ;
796       *
797       * le_zero: fmin(le_zero, ne_zero)
798       *        | fmin(le_zero, gt_zero)
799       *        | fmin(le_zero, ge_zero)
800       *        | fmin(le_zero, eq_zero)
801       *        | fmin(ne_zero, le_zero)  # Treat fmin as commutative
802       *        | fmin(gt_zero, le_zero)  # Treat fmin as commutative
803       *        | fmin(ge_zero, le_zero)  # Treat fmin as commutative
804       *        | fmin(eq_zero, le_zero)  # Treat fmin as commutative
805       *        | fmin(le_zero, le_zero)
806       *        ;
807       *
808       * ge_zero: fmin(ge_zero, gt_zero)
809       *        | fmin(gt_zero, ge_zero)  # Treat fmin as commutative
810       *        | fmin(ge_zero, ge_zero)
811       *        ;
812       *
813       * gt_zero: fmin(gt_zero, gt_zero)
814       *        ;
815       *
816       * ne_zero: fmin(ne_zero, gt_zero)
817       *        | fmin(gt_zero, ne_zero)  # Treat fmin as commutative
818       *        | fmin(ne_zero, ne_zero)
819       *        ;
820       *
821       * eq_zero: fmin(eq_zero, ge_zero)
822       *        | fmin(eq_zero, gt_zero)
823       *        | fmin(ge_zero, eq_zero)  # Treat fmin as commutative
824       *        | fmin(gt_zero, eq_zero)  # Treat fmin as commutative
825       *        | fmin(eq_zero, eq_zero)
826       *        ;
827       *
828       * All other cases are 'unknown'.
829       */
830      static const enum ssa_ranges table[last_range + 1][last_range + 1] = {
831         /* left\right   unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
832         /* unknown */ { _______, lt_zero, le_zero, _______, _______, _______, _______ },
833         /* lt_zero */ { lt_zero, lt_zero, lt_zero, lt_zero, lt_zero, lt_zero, lt_zero },
834         /* le_zero */ { le_zero, lt_zero, le_zero, le_zero, le_zero, le_zero, le_zero },
835         /* gt_zero */ { _______, lt_zero, le_zero, gt_zero, ge_zero, ne_zero, eq_zero },
836         /* ge_zero */ { _______, lt_zero, le_zero, ge_zero, ge_zero, _______, eq_zero },
837         /* ne_zero */ { _______, lt_zero, le_zero, ne_zero, _______, ne_zero, _______ },
838         /* eq_zero */ { _______, lt_zero, le_zero, eq_zero, eq_zero, _______, eq_zero }
839      };
840
841      /* Treat fmin as commutative. */
842      ASSERT_TABLE_IS_COMMUTATIVE(table);
843      ASSERT_TABLE_IS_DIAGONAL(table);
844      ASSERT_UNION_OF_OTHERS_MATCHES_UNKNOWN_2_SOURCE(table);
845
846      r.range = table[left.range][right.range];
847
848      /* Recall that when either value is NaN, fmin will pick the other value.
849       * This means the result range of the fmin will either be the "ideal"
850       * result range (calculated above) or the range of the non-NaN value.
851       */
852      if (!left.is_a_number)
853         r.range = union_ranges(r.range, right.range);
854
855      if (!right.is_a_number)
856         r.range = union_ranges(r.range, left.range);
857
858      break;
859   }
860
861   case nir_op_fmul: {
862      const struct ssa_result_range left =
863         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
864      const struct ssa_result_range right =
865         analyze_expression(alu, 1, ht, nir_alu_src_type(alu, 1));
866
867      r.is_integral = left.is_integral && right.is_integral;
868
869      /* x * x => ge_zero */
870      if (left.range != eq_zero && nir_alu_srcs_equal(alu, alu, 0, 1)) {
871         /* Even if x > 0, the result of x*x can be zero when x is, for
872          * example, a subnormal number.
873          */
874         r.range = ge_zero;
875      } else if (left.range != eq_zero && nir_alu_srcs_negative_equal(alu, alu, 0, 1)) {
876         /* -x * x => le_zero. */
877         r.range = le_zero;
878      } else
879         r.range = fmul_table[left.range][right.range];
880
881      /* Mulitpliation produces NaN for X * NaN and for 0 * ±Inf.  If both
882       * operands are numbers and either both are finite or one is finite and
883       * the other cannot be zero, then the result must be a number.
884       */
885      r.is_a_number = (left.is_a_number && right.is_a_number) &&
886         ((left.is_finite && right.is_finite) ||
887          (!is_not_zero(left.range) && right.is_finite) ||
888          (left.is_finite && !is_not_zero(right.range)));
889
890      break;
891   }
892
893   case nir_op_frcp:
894      r = (struct ssa_result_range){
895         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0)).range,
896         false,
897         false, /* Various cases can result in NaN, so assume the worst. */
898         false  /*    "      "    "     "    "  "    "    "    "    "    */
899      };
900      break;
901
902   case nir_op_mov:
903      r = analyze_expression(alu, 0, ht, use_type);
904      break;
905
906   case nir_op_fneg:
907      r = analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
908
909      r.range = fneg_table[r.range];
910      break;
911
912   case nir_op_fsat: {
913      const struct ssa_result_range left =
914         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
915
916      /* fsat(NaN) = 0. */
917      r.is_a_number = true;
918      r.is_finite = true;
919
920      switch (left.range) {
921      case le_zero:
922      case lt_zero:
923      case eq_zero:
924         r.range = eq_zero;
925         r.is_integral = true;
926         break;
927
928      case gt_zero:
929         /* fsat is equivalent to fmin(fmax(X, 0.0), 1.0), so if X is not a
930          * number, the result will be 0.
931          */
932         r.range = left.is_a_number ? gt_zero : ge_zero;
933         r.is_integral = left.is_integral;
934         break;
935
936      case ge_zero:
937      case ne_zero:
938      case unknown:
939         /* Since the result must be in [0, 1], the value must be >= 0. */
940         r.range = ge_zero;
941         r.is_integral = left.is_integral;
942         break;
943      }
944      break;
945   }
946
947   case nir_op_fsign:
948      r = (struct ssa_result_range){
949         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0)).range,
950         true,
951         true, /* fsign is -1, 0, or 1, even for NaN, so it must be a number. */
952         true  /* fsign is -1, 0, or 1, even for NaN, so it must be finite. */
953      };
954      break;
955
956   case nir_op_fsqrt:
957   case nir_op_frsq:
958      r = (struct ssa_result_range){ge_zero, false, false, false};
959      break;
960
961   case nir_op_ffloor: {
962      const struct ssa_result_range left =
963         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
964
965      r.is_integral = true;
966
967      /* In IEEE 754, floor(NaN) is NaN, and floor(±Inf) is ±Inf. See
968       * https://pubs.opengroup.org/onlinepubs/9699919799.2016edition/functions/floor.html
969       */
970      r.is_a_number = left.is_a_number;
971      r.is_finite = left.is_finite;
972
973      if (left.is_integral || left.range == le_zero || left.range == lt_zero)
974         r.range = left.range;
975      else if (left.range == ge_zero || left.range == gt_zero)
976         r.range = ge_zero;
977      else if (left.range == ne_zero)
978         r.range = unknown;
979
980      break;
981   }
982
983   case nir_op_fceil: {
984      const struct ssa_result_range left =
985         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
986
987      r.is_integral = true;
988
989      /* In IEEE 754, ceil(NaN) is NaN, and ceil(±Inf) is ±Inf. See
990       * https://pubs.opengroup.org/onlinepubs/9699919799.2016edition/functions/ceil.html
991       */
992      r.is_a_number = left.is_a_number;
993      r.is_finite = left.is_finite;
994
995      if (left.is_integral || left.range == ge_zero || left.range == gt_zero)
996         r.range = left.range;
997      else if (left.range == le_zero || left.range == lt_zero)
998         r.range = le_zero;
999      else if (left.range == ne_zero)
1000         r.range = unknown;
1001
1002      break;
1003   }
1004
1005   case nir_op_ftrunc: {
1006      const struct ssa_result_range left =
1007         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
1008
1009      r.is_integral = true;
1010
1011      /* In IEEE 754, trunc(NaN) is NaN, and trunc(±Inf) is ±Inf.  See
1012       * https://pubs.opengroup.org/onlinepubs/9699919799.2016edition/functions/trunc.html
1013       */
1014      r.is_a_number = left.is_a_number;
1015      r.is_finite = left.is_finite;
1016
1017      if (left.is_integral)
1018         r.range = left.range;
1019      else if (left.range == ge_zero || left.range == gt_zero)
1020         r.range = ge_zero;
1021      else if (left.range == le_zero || left.range == lt_zero)
1022         r.range = le_zero;
1023      else if (left.range == ne_zero)
1024         r.range = unknown;
1025
1026      break;
1027   }
1028
1029   case nir_op_flt:
1030   case nir_op_fge:
1031   case nir_op_feq:
1032   case nir_op_fneu:
1033   case nir_op_ilt:
1034   case nir_op_ige:
1035   case nir_op_ieq:
1036   case nir_op_ine:
1037   case nir_op_ult:
1038   case nir_op_uge:
1039      /* Boolean results are 0 or -1. */
1040      r = (struct ssa_result_range){le_zero, false, true, false};
1041      break;
1042
1043   case nir_op_fpow: {
1044      /* Due to flush-to-zero semanatics of floating-point numbers with very
1045       * small mangnitudes, we can never really be sure a result will be
1046       * non-zero.
1047       *
1048       * NIR uses pow() and powf() to constant evaluate nir_op_fpow.  The man
1049       * page for that function says:
1050       *
1051       *    If y is 0, the result is 1.0 (even if x is a NaN).
1052       *
1053       * gt_zero: pow(*, eq_zero)
1054       *        | pow(eq_zero, lt_zero)   # 0^-y = +inf
1055       *        | pow(eq_zero, le_zero)   # 0^-y = +inf or 0^0 = 1.0
1056       *        ;
1057       *
1058       * eq_zero: pow(eq_zero, gt_zero)
1059       *        ;
1060       *
1061       * ge_zero: pow(gt_zero, gt_zero)
1062       *        | pow(gt_zero, ge_zero)
1063       *        | pow(gt_zero, lt_zero)
1064       *        | pow(gt_zero, le_zero)
1065       *        | pow(gt_zero, ne_zero)
1066       *        | pow(gt_zero, unknown)
1067       *        | pow(ge_zero, gt_zero)
1068       *        | pow(ge_zero, ge_zero)
1069       *        | pow(ge_zero, lt_zero)
1070       *        | pow(ge_zero, le_zero)
1071       *        | pow(ge_zero, ne_zero)
1072       *        | pow(ge_zero, unknown)
1073       *        | pow(eq_zero, ge_zero)  # 0^0 = 1.0 or 0^+y = 0.0
1074       *        | pow(eq_zero, ne_zero)  # 0^-y = +inf or 0^+y = 0.0
1075       *        | pow(eq_zero, unknown)  # union of all other y cases
1076       *        ;
1077       *
1078       * All other cases are unknown.
1079       *
1080       * We could do better if the right operand is a constant, integral
1081       * value.
1082       */
1083      static const enum ssa_ranges table[last_range + 1][last_range + 1] = {
1084         /* left\right   unknown  lt_zero  le_zero  gt_zero  ge_zero  ne_zero  eq_zero */
1085         /* unknown */ { _______, _______, _______, _______, _______, _______, gt_zero },
1086         /* lt_zero */ { _______, _______, _______, _______, _______, _______, gt_zero },
1087         /* le_zero */ { _______, _______, _______, _______, _______, _______, gt_zero },
1088         /* gt_zero */ { ge_zero, ge_zero, ge_zero, ge_zero, ge_zero, ge_zero, gt_zero },
1089         /* ge_zero */ { ge_zero, ge_zero, ge_zero, ge_zero, ge_zero, ge_zero, gt_zero },
1090         /* ne_zero */ { _______, _______, _______, _______, _______, _______, gt_zero },
1091         /* eq_zero */ { ge_zero, gt_zero, gt_zero, eq_zero, ge_zero, ge_zero, gt_zero },
1092      };
1093
1094      const struct ssa_result_range left =
1095         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
1096      const struct ssa_result_range right =
1097         analyze_expression(alu, 1, ht, nir_alu_src_type(alu, 1));
1098
1099      ASSERT_UNION_OF_DISJOINT_MATCHES_UNKNOWN_2_SOURCE(table);
1100      ASSERT_UNION_OF_EQ_AND_STRICT_INEQ_MATCHES_NONSTRICT_2_SOURCE(table);
1101
1102      r.is_integral = left.is_integral && right.is_integral &&
1103                      is_not_negative(right.range);
1104      r.range = table[left.range][right.range];
1105
1106      /* Various cases can result in NaN, so assume the worst. */
1107      r.is_a_number = false;
1108
1109      break;
1110   }
1111
1112   case nir_op_ffma: {
1113      const struct ssa_result_range first =
1114         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
1115      const struct ssa_result_range second =
1116         analyze_expression(alu, 1, ht, nir_alu_src_type(alu, 1));
1117      const struct ssa_result_range third =
1118         analyze_expression(alu, 2, ht, nir_alu_src_type(alu, 2));
1119
1120      r.is_integral = first.is_integral && second.is_integral &&
1121                      third.is_integral;
1122
1123      /* Various cases can result in NaN, so assume the worst. */
1124      r.is_a_number = false;
1125
1126      enum ssa_ranges fmul_range;
1127
1128      if (first.range != eq_zero && nir_alu_srcs_equal(alu, alu, 0, 1)) {
1129         /* See handling of nir_op_fmul for explanation of why ge_zero is the
1130          * range.
1131          */
1132         fmul_range = ge_zero;
1133      } else if (first.range != eq_zero && nir_alu_srcs_negative_equal(alu, alu, 0, 1)) {
1134         /* -x * x => le_zero */
1135         fmul_range = le_zero;
1136      } else
1137         fmul_range = fmul_table[first.range][second.range];
1138
1139      r.range = fadd_table[fmul_range][third.range];
1140      break;
1141   }
1142
1143   case nir_op_flrp: {
1144      const struct ssa_result_range first =
1145         analyze_expression(alu, 0, ht, nir_alu_src_type(alu, 0));
1146      const struct ssa_result_range second =
1147         analyze_expression(alu, 1, ht, nir_alu_src_type(alu, 1));
1148      const struct ssa_result_range third =
1149         analyze_expression(alu, 2, ht, nir_alu_src_type(alu, 2));
1150
1151      r.is_integral = first.is_integral && second.is_integral &&
1152                      third.is_integral;
1153
1154      /* Various cases can result in NaN, so assume the worst. */
1155      r.is_a_number = false;
1156
1157      /* Decompose the flrp to first + third * (second + -first) */
1158      const enum ssa_ranges inner_fadd_range =
1159         fadd_table[second.range][fneg_table[first.range]];
1160
1161      const enum ssa_ranges fmul_range =
1162         fmul_table[third.range][inner_fadd_range];
1163
1164      r.range = fadd_table[first.range][fmul_range];
1165      break;
1166   }
1167
1168   default:
1169      r = (struct ssa_result_range){unknown, false, false, false};
1170      break;
1171   }
1172
1173   if (r.range == eq_zero)
1174      r.is_integral = true;
1175
1176   /* Just like isfinite(), the is_finite flag implies the value is a number. */
1177   assert((int) r.is_finite <= (int) r.is_a_number);
1178
1179   _mesa_hash_table_insert(ht, pack_key(alu, use_type), pack_data(r));
1180   return r;
1181}
1182
1183#undef _______
1184
1185struct ssa_result_range
1186nir_analyze_range(struct hash_table *range_ht,
1187                  const nir_alu_instr *instr, unsigned src)
1188{
1189   return analyze_expression(instr, src, range_ht,
1190                             nir_alu_src_type(instr, src));
1191}
1192
1193static uint32_t bitmask(uint32_t size) {
1194   return size >= 32 ? 0xffffffffu : ((uint32_t)1 << size) - 1u;
1195}
1196
1197static uint64_t mul_clamp(uint32_t a, uint32_t b)
1198{
1199   if (a != 0 && (a * b) / a != b)
1200      return (uint64_t)UINT32_MAX + 1;
1201   else
1202      return a * b;
1203}
1204
1205/* recursively gather at most "buf_size" phi/bcsel sources */
1206static unsigned
1207search_phi_bcsel(nir_ssa_scalar scalar, nir_ssa_scalar *buf, unsigned buf_size, struct set *visited)
1208{
1209   if (_mesa_set_search(visited, scalar.def))
1210      return 0;
1211   _mesa_set_add(visited, scalar.def);
1212
1213   if (scalar.def->parent_instr->type == nir_instr_type_phi) {
1214      nir_phi_instr *phi = nir_instr_as_phi(scalar.def->parent_instr);
1215      unsigned num_sources_left = exec_list_length(&phi->srcs);
1216      if (buf_size >= num_sources_left) {
1217         unsigned total_added = 0;
1218         nir_foreach_phi_src(src, phi) {
1219            num_sources_left--;
1220            unsigned added = search_phi_bcsel(
1221               (nir_ssa_scalar){src->src.ssa, 0}, buf + total_added, buf_size - num_sources_left, visited);
1222            assert(added <= buf_size);
1223            buf_size -= added;
1224            total_added += added;
1225         }
1226         return total_added;
1227      }
1228   }
1229
1230   if (nir_ssa_scalar_is_alu(scalar)) {
1231      nir_op op = nir_ssa_scalar_alu_op(scalar);
1232
1233      if ((op == nir_op_bcsel || op == nir_op_b32csel) && buf_size >= 2) {
1234         nir_ssa_scalar src0 = nir_ssa_scalar_chase_alu_src(scalar, 0);
1235         nir_ssa_scalar src1 = nir_ssa_scalar_chase_alu_src(scalar, 1);
1236
1237         unsigned added = search_phi_bcsel(src0, buf, buf_size - 1, visited);
1238         buf_size -= added;
1239         added += search_phi_bcsel(src1, buf + added, buf_size, visited);
1240         return added;
1241      }
1242   }
1243
1244   buf[0] = scalar;
1245   return 1;
1246}
1247
1248static nir_variable *
1249lookup_input(nir_shader *shader, unsigned driver_location)
1250{
1251   return nir_find_variable_with_driver_location(shader, nir_var_shader_in,
1252                                                 driver_location);
1253}
1254
1255/* The config here should be generic enough to be correct on any HW. */
1256static const nir_unsigned_upper_bound_config default_ub_config = {
1257   .min_subgroup_size = 1u,
1258   .max_subgroup_size = UINT16_MAX,
1259   .max_workgroup_invocations = UINT16_MAX,
1260   .max_workgroup_count = {UINT16_MAX, UINT16_MAX, UINT16_MAX},
1261   .max_workgroup_size = {UINT16_MAX, UINT16_MAX, UINT16_MAX},
1262   .vertex_attrib_max = {
1263      UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX,
1264      UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX,
1265      UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX,
1266      UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX,
1267   },
1268};
1269
1270uint32_t
1271nir_unsigned_upper_bound(nir_shader *shader, struct hash_table *range_ht,
1272                         nir_ssa_scalar scalar,
1273                         const nir_unsigned_upper_bound_config *config)
1274{
1275   assert(scalar.def->bit_size <= 32);
1276
1277   if (!config)
1278      config = &default_ub_config;
1279   if (nir_ssa_scalar_is_const(scalar))
1280      return nir_ssa_scalar_as_uint(scalar);
1281
1282   /* keys can't be 0, so we have to add 1 to the index */
1283   void *key = (void*)(((uintptr_t)(scalar.def->index + 1) << 4) | scalar.comp);
1284   struct hash_entry *he = _mesa_hash_table_search(range_ht, key);
1285   if (he != NULL)
1286      return (uintptr_t)he->data;
1287
1288   uint32_t max = bitmask(scalar.def->bit_size);
1289
1290   if (scalar.def->parent_instr->type == nir_instr_type_intrinsic) {
1291      uint32_t res = max;
1292      nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(scalar.def->parent_instr);
1293      switch (intrin->intrinsic) {
1294      case nir_intrinsic_load_local_invocation_index:
1295         /* The local invocation index is used under the hood by RADV for
1296          * some non-compute-like shaders (eg. LS and NGG). These technically
1297          * run in workgroups on the HW, even though this fact is not exposed
1298          * by the API.
1299          * They can safely use the same code path here as variable sized
1300          * compute-like shader stages.
1301          */
1302         if (!gl_shader_stage_uses_workgroup(shader->info.stage) ||
1303             shader->info.workgroup_size_variable) {
1304            res = config->max_workgroup_invocations - 1;
1305         } else {
1306            res = (shader->info.workgroup_size[0] *
1307                   shader->info.workgroup_size[1] *
1308                   shader->info.workgroup_size[2]) - 1u;
1309         }
1310         break;
1311      case nir_intrinsic_load_local_invocation_id:
1312         if (shader->info.workgroup_size_variable)
1313            res = config->max_workgroup_size[scalar.comp] - 1u;
1314         else
1315            res = shader->info.workgroup_size[scalar.comp] - 1u;
1316         break;
1317      case nir_intrinsic_load_workgroup_id:
1318         res = config->max_workgroup_count[scalar.comp] - 1u;
1319         break;
1320      case nir_intrinsic_load_num_workgroups:
1321         res = config->max_workgroup_count[scalar.comp];
1322         break;
1323      case nir_intrinsic_load_global_invocation_id:
1324         if (shader->info.workgroup_size_variable) {
1325            res = mul_clamp(config->max_workgroup_size[scalar.comp],
1326                            config->max_workgroup_count[scalar.comp]) - 1u;
1327         } else {
1328            res = (shader->info.workgroup_size[scalar.comp] *
1329                   config->max_workgroup_count[scalar.comp]) - 1u;
1330         }
1331         break;
1332      case nir_intrinsic_load_invocation_id:
1333         if (shader->info.stage == MESA_SHADER_TESS_CTRL)
1334            res = shader->info.tess.tcs_vertices_out
1335                  ? (shader->info.tess.tcs_vertices_out - 1)
1336                  : 511; /* Generous maximum output patch size of 512 */
1337         break;
1338      case nir_intrinsic_load_subgroup_invocation:
1339      case nir_intrinsic_first_invocation:
1340         res = config->max_subgroup_size - 1;
1341         break;
1342      case nir_intrinsic_mbcnt_amd: {
1343         uint32_t src0 = config->max_subgroup_size - 1;
1344         uint32_t src1 = nir_unsigned_upper_bound(shader, range_ht, (nir_ssa_scalar){intrin->src[1].ssa, 0}, config);
1345
1346         if (src0 + src1 < src0)
1347            res = max; /* overflow */
1348         else
1349            res = src0 + src1;
1350         break;
1351      }
1352      case nir_intrinsic_load_subgroup_size:
1353         res = config->max_subgroup_size;
1354         break;
1355      case nir_intrinsic_load_subgroup_id:
1356      case nir_intrinsic_load_num_subgroups: {
1357         uint32_t workgroup_size = config->max_workgroup_invocations;
1358         if (gl_shader_stage_uses_workgroup(shader->info.stage) &&
1359             !shader->info.workgroup_size_variable) {
1360            workgroup_size = shader->info.workgroup_size[0] *
1361                             shader->info.workgroup_size[1] *
1362                             shader->info.workgroup_size[2];
1363         }
1364         res = DIV_ROUND_UP(workgroup_size, config->min_subgroup_size);
1365         if (intrin->intrinsic == nir_intrinsic_load_subgroup_id)
1366            res--;
1367         break;
1368      }
1369      case nir_intrinsic_load_input: {
1370         if (shader->info.stage == MESA_SHADER_VERTEX && nir_src_is_const(intrin->src[0])) {
1371            nir_variable *var = lookup_input(shader, nir_intrinsic_base(intrin));
1372            if (var) {
1373               int loc = var->data.location - VERT_ATTRIB_GENERIC0;
1374               if (loc >= 0)
1375                  res = config->vertex_attrib_max[loc];
1376            }
1377         }
1378         break;
1379      }
1380      case nir_intrinsic_reduce:
1381      case nir_intrinsic_inclusive_scan:
1382      case nir_intrinsic_exclusive_scan: {
1383         nir_op op = nir_intrinsic_reduction_op(intrin);
1384         if (op == nir_op_umin || op == nir_op_umax || op == nir_op_imin || op == nir_op_imax)
1385            res = nir_unsigned_upper_bound(shader, range_ht, (nir_ssa_scalar){intrin->src[0].ssa, 0}, config);
1386         break;
1387      }
1388      case nir_intrinsic_read_first_invocation:
1389      case nir_intrinsic_read_invocation:
1390      case nir_intrinsic_shuffle:
1391      case nir_intrinsic_shuffle_xor:
1392      case nir_intrinsic_shuffle_up:
1393      case nir_intrinsic_shuffle_down:
1394      case nir_intrinsic_quad_broadcast:
1395      case nir_intrinsic_quad_swap_horizontal:
1396      case nir_intrinsic_quad_swap_vertical:
1397      case nir_intrinsic_quad_swap_diagonal:
1398      case nir_intrinsic_quad_swizzle_amd:
1399      case nir_intrinsic_masked_swizzle_amd:
1400         res = nir_unsigned_upper_bound(shader, range_ht, (nir_ssa_scalar){intrin->src[0].ssa, 0}, config);
1401         break;
1402      case nir_intrinsic_write_invocation_amd: {
1403         uint32_t src0 = nir_unsigned_upper_bound(shader, range_ht, (nir_ssa_scalar){intrin->src[0].ssa, 0}, config);
1404         uint32_t src1 = nir_unsigned_upper_bound(shader, range_ht, (nir_ssa_scalar){intrin->src[1].ssa, 0}, config);
1405         res = MAX2(src0, src1);
1406         break;
1407      }
1408      case nir_intrinsic_load_tess_rel_patch_id_amd:
1409      case nir_intrinsic_load_tcs_num_patches_amd:
1410         /* Very generous maximum: TCS/TES executed by largest possible workgroup */
1411         res = config->max_workgroup_invocations / MAX2(shader->info.tess.tcs_vertices_out, 1u);
1412         break;
1413      default:
1414         break;
1415      }
1416      if (res != max)
1417         _mesa_hash_table_insert(range_ht, key, (void*)(uintptr_t)res);
1418      return res;
1419   }
1420
1421   if (scalar.def->parent_instr->type == nir_instr_type_phi) {
1422      nir_cf_node *prev = nir_cf_node_prev(&scalar.def->parent_instr->block->cf_node);
1423
1424      uint32_t res = 0;
1425      if (!prev || prev->type == nir_cf_node_block) {
1426         _mesa_hash_table_insert(range_ht, key, (void*)(uintptr_t)max);
1427
1428         struct set *visited = _mesa_pointer_set_create(NULL);
1429         nir_ssa_scalar defs[64];
1430         unsigned def_count = search_phi_bcsel(scalar, defs, 64, visited);
1431         _mesa_set_destroy(visited, NULL);
1432
1433         for (unsigned i = 0; i < def_count; i++)
1434            res = MAX2(res, nir_unsigned_upper_bound(shader, range_ht, defs[i], config));
1435      } else {
1436         nir_foreach_phi_src(src, nir_instr_as_phi(scalar.def->parent_instr)) {
1437            res = MAX2(res, nir_unsigned_upper_bound(
1438               shader, range_ht, (nir_ssa_scalar){src->src.ssa, 0}, config));
1439         }
1440      }
1441
1442      _mesa_hash_table_insert(range_ht, key, (void*)(uintptr_t)res);
1443      return res;
1444   }
1445
1446   if (nir_ssa_scalar_is_alu(scalar)) {
1447      nir_op op = nir_ssa_scalar_alu_op(scalar);
1448
1449      switch (op) {
1450      case nir_op_umin:
1451      case nir_op_imin:
1452      case nir_op_imax:
1453      case nir_op_umax:
1454      case nir_op_iand:
1455      case nir_op_ior:
1456      case nir_op_ixor:
1457      case nir_op_ishl:
1458      case nir_op_imul:
1459      case nir_op_ushr:
1460      case nir_op_ishr:
1461      case nir_op_iadd:
1462      case nir_op_umod:
1463      case nir_op_udiv:
1464      case nir_op_bcsel:
1465      case nir_op_b32csel:
1466      case nir_op_ubfe:
1467      case nir_op_bfm:
1468      case nir_op_fmul:
1469      case nir_op_extract_u8:
1470      case nir_op_extract_i8:
1471      case nir_op_extract_u16:
1472      case nir_op_extract_i16:
1473         break;
1474      case nir_op_u2u1:
1475      case nir_op_u2u8:
1476      case nir_op_u2u16:
1477      case nir_op_u2u32:
1478      case nir_op_f2u32:
1479         if (nir_ssa_scalar_chase_alu_src(scalar, 0).def->bit_size > 32) {
1480            /* If src is >32 bits, return max */
1481            return max;
1482         }
1483         break;
1484      default:
1485         return max;
1486      }
1487
1488      uint32_t src0 = nir_unsigned_upper_bound(shader, range_ht, nir_ssa_scalar_chase_alu_src(scalar, 0), config);
1489      uint32_t src1 = max, src2 = max;
1490      if (nir_op_infos[op].num_inputs > 1)
1491         src1 = nir_unsigned_upper_bound(shader, range_ht, nir_ssa_scalar_chase_alu_src(scalar, 1), config);
1492      if (nir_op_infos[op].num_inputs > 2)
1493         src2 = nir_unsigned_upper_bound(shader, range_ht, nir_ssa_scalar_chase_alu_src(scalar, 2), config);
1494
1495      uint32_t res = max;
1496      switch (op) {
1497      case nir_op_umin:
1498         res = src0 < src1 ? src0 : src1;
1499         break;
1500      case nir_op_imin:
1501      case nir_op_imax:
1502      case nir_op_umax:
1503         res = src0 > src1 ? src0 : src1;
1504         break;
1505      case nir_op_iand:
1506         res = bitmask(util_last_bit64(src0)) & bitmask(util_last_bit64(src1));
1507         break;
1508      case nir_op_ior:
1509      case nir_op_ixor:
1510         res = bitmask(util_last_bit64(src0)) | bitmask(util_last_bit64(src1));
1511         break;
1512      case nir_op_ishl:
1513         if (util_last_bit64(src0) + src1 > scalar.def->bit_size)
1514            res = max; /* overflow */
1515         else
1516            res = src0 << MIN2(src1, scalar.def->bit_size - 1u);
1517         break;
1518      case nir_op_imul:
1519         if (src0 != 0 && (src0 * src1) / src0 != src1)
1520            res = max;
1521         else
1522            res = src0 * src1;
1523         break;
1524      case nir_op_ushr: {
1525         nir_ssa_scalar src1_scalar = nir_ssa_scalar_chase_alu_src(scalar, 1);
1526         if (nir_ssa_scalar_is_const(src1_scalar))
1527            res = src0 >> nir_ssa_scalar_as_uint(src1_scalar);
1528         else
1529            res = src0;
1530         break;
1531      }
1532      case nir_op_ishr: {
1533         nir_ssa_scalar src1_scalar = nir_ssa_scalar_chase_alu_src(scalar, 1);
1534         if (src0 <= 2147483647 && nir_ssa_scalar_is_const(src1_scalar))
1535            res = src0 >> nir_ssa_scalar_as_uint(src1_scalar);
1536         else
1537            res = src0;
1538         break;
1539      }
1540      case nir_op_iadd:
1541         if (src0 + src1 < src0)
1542            res = max; /* overflow */
1543         else
1544            res = src0 + src1;
1545         break;
1546      case nir_op_umod:
1547         res = src1 ? src1 - 1 : 0;
1548         break;
1549      case nir_op_udiv: {
1550         nir_ssa_scalar src1_scalar = nir_ssa_scalar_chase_alu_src(scalar, 1);
1551         if (nir_ssa_scalar_is_const(src1_scalar))
1552            res = nir_ssa_scalar_as_uint(src1_scalar) ? src0 / nir_ssa_scalar_as_uint(src1_scalar) : 0;
1553         else
1554            res = src0;
1555         break;
1556      }
1557      case nir_op_bcsel:
1558      case nir_op_b32csel:
1559         res = src1 > src2 ? src1 : src2;
1560         break;
1561      case nir_op_ubfe:
1562         res = bitmask(MIN2(src2, scalar.def->bit_size));
1563         break;
1564      case nir_op_bfm: {
1565         nir_ssa_scalar src1_scalar = nir_ssa_scalar_chase_alu_src(scalar, 1);
1566         if (nir_ssa_scalar_is_const(src1_scalar)) {
1567            src0 = MIN2(src0, 31);
1568            src1 = nir_ssa_scalar_as_uint(src1_scalar) & 0x1fu;
1569            res = bitmask(src0) << src1;
1570         } else {
1571            src0 = MIN2(src0, 31);
1572            src1 = MIN2(src1, 31);
1573            res = bitmask(MIN2(src0 + src1, 32));
1574         }
1575         break;
1576      }
1577      /* limited floating-point support for f2u32(fmul(load_input(), <constant>)) */
1578      case nir_op_f2u32:
1579         /* infinity/NaN starts at 0x7f800000u, negative numbers at 0x80000000 */
1580         if (src0 < 0x7f800000u) {
1581            float val;
1582            memcpy(&val, &src0, 4);
1583            res = (uint32_t)val;
1584         }
1585         break;
1586      case nir_op_fmul:
1587         /* infinity/NaN starts at 0x7f800000u, negative numbers at 0x80000000 */
1588         if (src0 < 0x7f800000u && src1 < 0x7f800000u) {
1589            float src0_f, src1_f;
1590            memcpy(&src0_f, &src0, 4);
1591            memcpy(&src1_f, &src1, 4);
1592            /* not a proper rounding-up multiplication, but should be good enough */
1593            float max_f = ceilf(src0_f) * ceilf(src1_f);
1594            memcpy(&res, &max_f, 4);
1595         }
1596         break;
1597      case nir_op_u2u1:
1598      case nir_op_u2u8:
1599      case nir_op_u2u16:
1600      case nir_op_u2u32:
1601         res = MIN2(src0, max);
1602         break;
1603      case nir_op_sad_u8x4:
1604         res = src2 + 4 * 255;
1605         break;
1606      case nir_op_extract_u8:
1607         res = MIN2(src0, UINT8_MAX);
1608         break;
1609      case nir_op_extract_i8:
1610         res = (src0 >= 0x80) ? max : MIN2(src0, INT8_MAX);
1611         break;
1612      case nir_op_extract_u16:
1613         res = MIN2(src0, UINT16_MAX);
1614         break;
1615      case nir_op_extract_i16:
1616         res = (src0 >= 0x8000) ? max : MIN2(src0, INT16_MAX);
1617         break;
1618      default:
1619         res = max;
1620         break;
1621      }
1622      _mesa_hash_table_insert(range_ht, key, (void*)(uintptr_t)res);
1623      return res;
1624   }
1625
1626   return max;
1627}
1628
1629bool
1630nir_addition_might_overflow(nir_shader *shader, struct hash_table *range_ht,
1631                            nir_ssa_scalar ssa, unsigned const_val,
1632                            const nir_unsigned_upper_bound_config *config)
1633{
1634   if (nir_ssa_scalar_is_alu(ssa)) {
1635      nir_op alu_op = nir_ssa_scalar_alu_op(ssa);
1636
1637      /* iadd(imul(a, #b), #c) */
1638      if (alu_op == nir_op_imul || alu_op == nir_op_ishl) {
1639         nir_ssa_scalar mul_src0 = nir_ssa_scalar_chase_alu_src(ssa, 0);
1640         nir_ssa_scalar mul_src1 = nir_ssa_scalar_chase_alu_src(ssa, 1);
1641         uint32_t stride = 1;
1642         if (nir_ssa_scalar_is_const(mul_src0))
1643            stride = nir_ssa_scalar_as_uint(mul_src0);
1644         else if (nir_ssa_scalar_is_const(mul_src1))
1645            stride = nir_ssa_scalar_as_uint(mul_src1);
1646
1647         if (alu_op == nir_op_ishl)
1648            stride = 1u << (stride % 32u);
1649
1650         if (!stride || const_val <= UINT32_MAX - (UINT32_MAX / stride * stride))
1651            return false;
1652      }
1653
1654      /* iadd(iand(a, #b), #c) */
1655      if (alu_op == nir_op_iand) {
1656         nir_ssa_scalar and_src0 = nir_ssa_scalar_chase_alu_src(ssa, 0);
1657         nir_ssa_scalar and_src1 = nir_ssa_scalar_chase_alu_src(ssa, 1);
1658         uint32_t mask = 0xffffffff;
1659         if (nir_ssa_scalar_is_const(and_src0))
1660            mask = nir_ssa_scalar_as_uint(and_src0);
1661         else if (nir_ssa_scalar_is_const(and_src1))
1662            mask = nir_ssa_scalar_as_uint(and_src1);
1663         if (mask == 0 || const_val < (1u << (ffs(mask) - 1)))
1664            return false;
1665      }
1666   }
1667
1668   uint32_t ub = nir_unsigned_upper_bound(shader, range_ht, ssa, config);
1669   return const_val + ub < const_val;
1670}
1671
1672static uint64_t
1673ssa_def_bits_used(nir_ssa_def *def, int recur)
1674{
1675   uint64_t bits_used = 0;
1676   uint64_t all_bits = BITFIELD64_MASK(def->bit_size);
1677
1678   /* Querying the bits used from a vector is too hard of a question to
1679    * answer.  Return the conservative answer that all bits are used.  To
1680    * handle this, the function would need to be extended to be a query of a
1681    * single component of the vector.  That would also necessary to fully
1682    * handle the 'num_components > 1' inside the loop below.
1683    *
1684    * FINISHME: This restriction will eventually need to be restricted to be
1685    * useful for hardware that uses u16vec2 as the native 16-bit integer type.
1686    */
1687   if (def->num_components > 1)
1688      return all_bits;
1689
1690   /* Limit recursion */
1691   if (recur-- <= 0)
1692      return all_bits;
1693
1694   nir_foreach_use(src, def) {
1695      switch (src->parent_instr->type) {
1696      case nir_instr_type_alu: {
1697         nir_alu_instr *use_alu = nir_instr_as_alu(src->parent_instr);
1698         unsigned src_idx = container_of(src, nir_alu_src, src) - use_alu->src;
1699
1700         /* If a user of the value produces a vector result, return the
1701          * conservative answer that all bits are used.  It is possible to
1702          * answer this query by looping over the components used.  For example,
1703          *
1704          * vec4 32 ssa_5 = load_const(0x0000f000, 0x00000f00, 0x000000f0, 0x0000000f)
1705          * ...
1706          * vec4 32 ssa_8 = iand ssa_7.xxxx, ssa_5
1707          *
1708          * could conceivably return 0x0000ffff when queyring the bits used of
1709          * ssa_7.  This is unlikely to be worth the effort because the
1710          * question can eventually answered after the shader has been
1711          * scalarized.
1712          */
1713         if (use_alu->dest.dest.ssa.num_components > 1)
1714            return all_bits;
1715
1716         switch (use_alu->op) {
1717         case nir_op_u2u8:
1718         case nir_op_i2i8:
1719            bits_used |= 0xff;
1720            break;
1721
1722         case nir_op_u2u16:
1723         case nir_op_i2i16:
1724            bits_used |= all_bits & 0xffff;
1725            break;
1726
1727         case nir_op_u2u32:
1728         case nir_op_i2i32:
1729            bits_used |= all_bits & 0xffffffff;
1730            break;
1731
1732         case nir_op_extract_u8:
1733         case nir_op_extract_i8:
1734            if (src_idx == 0 && nir_src_is_const(use_alu->src[1].src)) {
1735               unsigned chunk = nir_src_comp_as_uint(use_alu->src[1].src,
1736                                                     use_alu->src[1].swizzle[0]);
1737               bits_used |= 0xffull << (chunk * 8);
1738               break;
1739            } else {
1740               return all_bits;
1741            }
1742
1743         case nir_op_extract_u16:
1744         case nir_op_extract_i16:
1745            if (src_idx == 0 && nir_src_is_const(use_alu->src[1].src)) {
1746               unsigned chunk = nir_src_comp_as_uint(use_alu->src[1].src,
1747                                                     use_alu->src[1].swizzle[0]);
1748               bits_used |= 0xffffull << (chunk * 16);
1749               break;
1750            } else {
1751               return all_bits;
1752            }
1753
1754         case nir_op_ishl:
1755         case nir_op_ishr:
1756         case nir_op_ushr:
1757            if (src_idx == 1) {
1758               bits_used |= (nir_src_bit_size(use_alu->src[0].src) - 1);
1759               break;
1760            } else {
1761               return all_bits;
1762            }
1763
1764         case nir_op_iand:
1765            assert(src_idx < 2);
1766            if (nir_src_is_const(use_alu->src[1 - src_idx].src)) {
1767               uint64_t u64 = nir_src_comp_as_uint(use_alu->src[1 - src_idx].src,
1768                                                   use_alu->src[1 - src_idx].swizzle[0]);
1769               bits_used |= u64;
1770               break;
1771            } else {
1772               return all_bits;
1773            }
1774
1775         case nir_op_ior:
1776            assert(src_idx < 2);
1777            if (nir_src_is_const(use_alu->src[1 - src_idx].src)) {
1778               uint64_t u64 = nir_src_comp_as_uint(use_alu->src[1 - src_idx].src,
1779                                                   use_alu->src[1 - src_idx].swizzle[0]);
1780               bits_used |= all_bits & ~u64;
1781               break;
1782            } else {
1783               return all_bits;
1784            }
1785
1786         default:
1787            /* We don't know what this op does */
1788            return all_bits;
1789         }
1790         break;
1791      }
1792
1793      case nir_instr_type_intrinsic: {
1794         nir_intrinsic_instr *use_intrin =
1795            nir_instr_as_intrinsic(src->parent_instr);
1796         unsigned src_idx = src - use_intrin->src;
1797
1798         switch (use_intrin->intrinsic) {
1799         case nir_intrinsic_read_invocation:
1800         case nir_intrinsic_shuffle:
1801         case nir_intrinsic_shuffle_up:
1802         case nir_intrinsic_shuffle_down:
1803         case nir_intrinsic_shuffle_xor:
1804         case nir_intrinsic_quad_broadcast:
1805         case nir_intrinsic_quad_swap_horizontal:
1806         case nir_intrinsic_quad_swap_vertical:
1807         case nir_intrinsic_quad_swap_diagonal:
1808            if (src_idx == 0) {
1809               assert(use_intrin->dest.is_ssa);
1810               bits_used |= ssa_def_bits_used(&use_intrin->dest.ssa, recur);
1811            } else {
1812               if (use_intrin->intrinsic == nir_intrinsic_quad_broadcast) {
1813                  bits_used |= 3;
1814               } else {
1815                  /* Subgroups larger than 128 are not a thing */
1816                  bits_used |= 127;
1817               }
1818            }
1819            break;
1820
1821         case nir_intrinsic_reduce:
1822         case nir_intrinsic_inclusive_scan:
1823         case nir_intrinsic_exclusive_scan:
1824            assert(src_idx == 0);
1825            switch (nir_intrinsic_reduction_op(use_intrin)) {
1826            case nir_op_iadd:
1827            case nir_op_imul:
1828            case nir_op_ior:
1829            case nir_op_iand:
1830            case nir_op_ixor:
1831               bits_used |= ssa_def_bits_used(&use_intrin->dest.ssa, recur);
1832               break;
1833
1834            default:
1835               return all_bits;
1836            }
1837            break;
1838
1839         default:
1840            /* We don't know what this op does */
1841            return all_bits;
1842         }
1843         break;
1844      }
1845
1846      case nir_instr_type_phi: {
1847         nir_phi_instr *use_phi = nir_instr_as_phi(src->parent_instr);
1848         bits_used |= ssa_def_bits_used(&use_phi->dest.ssa, recur);
1849         break;
1850      }
1851
1852      default:
1853         return all_bits;
1854      }
1855
1856      /* If we've somehow shown that all our bits are used, we're done */
1857      assert((bits_used & ~all_bits) == 0);
1858      if (bits_used == all_bits)
1859         return all_bits;
1860   }
1861
1862   return bits_used;
1863}
1864
1865uint64_t
1866nir_ssa_def_bits_used(nir_ssa_def *def)
1867{
1868   return ssa_def_bits_used(def, 2);
1869}
1870