nir: don't turn ieq/ine into inot if used by an if
[mesa.git] / src / compiler / nir / nir_opt_algebraic.py
1 #! /usr/bin/env python
2 #
3 # Copyright (C) 2014 Intel Corporation
4 #
5 # Permission is hereby granted, free of charge, to any person obtaining a
6 # copy of this software and associated documentation files (the "Software"),
7 # to deal in the Software without restriction, including without limitation
8 # the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 # and/or sell copies of the Software, and to permit persons to whom the
10 # Software is furnished to do so, subject to the following conditions:
11 #
12 # The above copyright notice and this permission notice (including the next
13 # paragraph) shall be included in all copies or substantial portions of the
14 # Software.
15 #
16 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 # IN THE SOFTWARE.
23 #
24 # Authors:
25 # Jason Ekstrand (jason@jlekstrand.net)
26
27 import nir_algebraic
28
29 # Convenience variables
30 a = 'a'
31 b = 'b'
32 c = 'c'
33 d = 'd'
34
35 # Written in the form (<search>, <replace>) where <search> is an expression
36 # and <replace> is either an expression or a value. An expression is
37 # defined as a tuple of the form ([~]<op>, <src0>, <src1>, <src2>, <src3>)
38 # where each source is either an expression or a value. A value can be
39 # either a numeric constant or a string representing a variable name.
40 #
41 # If the opcode in a search expression is prefixed by a '~' character, this
42 # indicates that the operation is inexact. Such operations will only get
43 # applied to SSA values that do not have the exact bit set. This should be
44 # used by by any optimizations that are not bit-for-bit exact. It should not,
45 # however, be used for backend-requested lowering operations as those need to
46 # happen regardless of precision.
47 #
48 # Variable names are specified as "[#]name[@type][(cond)]" where "#" inicates
49 # that the given variable will only match constants and the type indicates that
50 # the given variable will only match values from ALU instructions with the
51 # given output type, and (cond) specifies an additional condition function
52 # (see nir_search_helpers.h).
53 #
54 # For constants, you have to be careful to make sure that it is the right
55 # type because python is unaware of the source and destination types of the
56 # opcodes.
57 #
58 # All expression types can have a bit-size specified. For opcodes, this
59 # looks like "op@32", for variables it is "a@32" or "a@uint32" to specify a
60 # type and size, and for literals, you can write "2.0@32". In the search half
61 # of the expression this indicates that it should only match that particular
62 # bit-size. In the replace half of the expression this indicates that the
63 # constructed value should have that bit-size.
64
65 optimizations = [
66
67 (('imul', a, '#b@32(is_pos_power_of_two)'), ('ishl', a, ('find_lsb', b))),
68 (('imul', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('ishl', a, ('find_lsb', ('iabs', b))))),
69 (('udiv', a, 1), a),
70 (('idiv', a, 1), a),
71 (('umod', a, 1), 0),
72 (('imod', a, 1), 0),
73 (('udiv', a, '#b@32(is_pos_power_of_two)'), ('ushr', a, ('find_lsb', b))),
74 (('idiv', a, '#b@32(is_pos_power_of_two)'), ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', b))), 'options->lower_idiv'),
75 (('idiv', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', ('iabs', b))))), 'options->lower_idiv'),
76 (('umod', a, '#b(is_pos_power_of_two)'), ('iand', a, ('isub', b, 1))),
77
78 (('fneg', ('fneg', a)), a),
79 (('ineg', ('ineg', a)), a),
80 (('fabs', ('fabs', a)), ('fabs', a)),
81 (('fabs', ('fneg', a)), ('fabs', a)),
82 (('fabs', ('u2f', a)), ('u2f', a)),
83 (('iabs', ('iabs', a)), ('iabs', a)),
84 (('iabs', ('ineg', a)), ('iabs', a)),
85 (('~fadd', a, 0.0), a),
86 (('iadd', a, 0), a),
87 (('usadd_4x8', a, 0), a),
88 (('usadd_4x8', a, ~0), ~0),
89 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
90 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
91 (('~fadd', ('fneg', a), a), 0.0),
92 (('iadd', ('ineg', a), a), 0),
93 (('iadd', ('ineg', a), ('iadd', a, b)), b),
94 (('iadd', a, ('iadd', ('ineg', a), b)), b),
95 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
96 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
97 (('~fmul', a, 0.0), 0.0),
98 (('imul', a, 0), 0),
99 (('umul_unorm_4x8', a, 0), 0),
100 (('umul_unorm_4x8', a, ~0), a),
101 (('fmul', a, 1.0), a),
102 (('imul', a, 1), a),
103 (('fmul', a, -1.0), ('fneg', a)),
104 (('imul', a, -1), ('ineg', a)),
105 (('~ffma', 0.0, a, b), b),
106 (('~ffma', a, 0.0, b), b),
107 (('~ffma', a, b, 0.0), ('fmul', a, b)),
108 (('ffma', a, 1.0, b), ('fadd', a, b)),
109 (('ffma', 1.0, a, b), ('fadd', a, b)),
110 (('~flrp', a, b, 0.0), a),
111 (('~flrp', a, b, 1.0), b),
112 (('~flrp', a, a, b), a),
113 (('~flrp', 0.0, a, b), ('fmul', a, b)),
114 (('~flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp32'),
115 (('~flrp', a, 0.0, c), ('fadd', ('fmul', ('fneg', a), c), a)),
116 (('flrp@32', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp32'),
117 (('flrp@64', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp64'),
118 (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'),
119 (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp32'),
120 (('~fadd@32', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp32'),
121 (('~fadd@64', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp64'),
122 (('~fadd', a, ('fmul', ('b2f', c), ('fadd', b, ('fneg', a)))), ('bcsel', c, b, a), 'options->lower_flrp32'),
123 (('~fadd@32', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp32'),
124 (('~fadd@64', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp64'),
125 (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'),
126 (('~fadd', ('fmul', a, b), c), ('ffma', a, b, c), 'options->fuse_ffma'),
127
128 # (a * #b + #c) << #d
129 # ((a * #b) << #d) + (#c << #d)
130 # (a * (#b << #d)) + (#c << #d)
131 (('ishl', ('iadd', ('imul', a, '#b'), '#c'), '#d'),
132 ('iadd', ('imul', a, ('ishl', b, d)), ('ishl', c, d))),
133
134 # (a * #b) << #c
135 # a * (#b << #c)
136 (('ishl', ('imul', a, '#b'), '#c'), ('imul', a, ('ishl', b, c))),
137
138 # Comparison simplifications
139 (('~inot', ('flt', a, b)), ('fge', a, b)),
140 (('~inot', ('fge', a, b)), ('flt', a, b)),
141 (('~inot', ('feq', a, b)), ('fne', a, b)),
142 (('~inot', ('fne', a, b)), ('feq', a, b)),
143 (('inot', ('ilt', a, b)), ('ige', a, b)),
144 (('inot', ('ige', a, b)), ('ilt', a, b)),
145 (('inot', ('ieq', a, b)), ('ine', a, b)),
146 (('inot', ('ine', a, b)), ('ieq', a, b)),
147
148 # 0.0 >= b2f(a)
149 # b2f(a) <= 0.0
150 # b2f(a) == 0.0 because b2f(a) can only be 0 or 1
151 # inot(a)
152 (('fge', 0.0, ('b2f', a)), ('inot', a)),
153
154 (('fge', ('fneg', ('b2f', a)), 0.0), ('inot', a)),
155
156 # 0.0 < fabs(a)
157 # fabs(a) > 0.0
158 # fabs(a) != 0.0 because fabs(a) must be >= 0
159 # a != 0.0
160 (('flt', 0.0, ('fabs', a)), ('fne', a, 0.0)),
161
162 (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
163 (('bcsel', ('flt', b, a), b, a), ('fmin', a, b)),
164 (('bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
165 (('bcsel', ('inot', a), b, c), ('bcsel', a, c, b)),
166 (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
167 (('bcsel', a, True, 'b@bool'), ('ior', a, b)),
168 (('fmin', a, a), a),
169 (('fmax', a, a), a),
170 (('imin', a, a), a),
171 (('imax', a, a), a),
172 (('umin', a, a), a),
173 (('umax', a, a), a),
174 (('~fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
175 (('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
176 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
177 (('fsat', ('fsat', a)), ('fsat', a)),
178 (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
179 (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
180 (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
181 (('fmax', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmax', a, b))),
182 (('fmin', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmin', a, b))),
183 (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
184 (('~ior', ('flt', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
185 (('~ior', ('flt', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
186 (('~ior', ('fge', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
187 (('~ior', ('fge', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
188 (('fabs', ('slt', a, b)), ('slt', a, b)),
189 (('fabs', ('sge', a, b)), ('sge', a, b)),
190 (('fabs', ('seq', a, b)), ('seq', a, b)),
191 (('fabs', ('sne', a, b)), ('sne', a, b)),
192 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
193 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
194 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
195 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
196 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
197 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
198 # Emulating booleans
199 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
200 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
201 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
202 (('iand', 'a@bool', 1.0), ('b2f', a)),
203 # True/False are ~0 and 0 in NIR. b2i of True is 1, and -1 is ~0 (True).
204 (('ineg', ('b2i', a)), a),
205 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
206 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
207 # Comparison with the same args. Note that these are not done for
208 # the float versions because NaN always returns false on float
209 # inequalities.
210 (('ilt', a, a), False),
211 (('ige', a, a), True),
212 (('ieq', a, a), True),
213 (('ine', a, a), False),
214 (('ult', a, a), False),
215 (('uge', a, a), True),
216 # Logical and bit operations
217 (('fand', a, 0.0), 0.0),
218 (('iand', a, a), a),
219 (('iand', a, ~0), a),
220 (('iand', a, 0), 0),
221 (('ior', a, a), a),
222 (('ior', a, 0), a),
223 (('ior', a, True), True),
224 (('fxor', a, a), 0.0),
225 (('ixor', a, a), 0),
226 (('ixor', a, 0), a),
227 (('inot', ('inot', a)), a),
228 # DeMorgan's Laws
229 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
230 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
231 # Shift optimizations
232 (('ishl', 0, a), 0),
233 (('ishl', a, 0), a),
234 (('ishr', 0, a), 0),
235 (('ishr', a, 0), a),
236 (('ushr', 0, a), 0),
237 (('ushr', a, 0), a),
238 (('iand', 0xff, ('ushr', a, 24)), ('ushr', a, 24)),
239 (('iand', 0xffff, ('ushr', a, 16)), ('ushr', a, 16)),
240 # Exponential/logarithmic identities
241 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
242 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
243 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
244 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
245 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
246 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
247 (('~fpow', a, 1.0), a),
248 (('~fpow', a, 2.0), ('fmul', a, a)),
249 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
250 (('~fpow', 2.0, a), ('fexp2', a)),
251 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
252 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
253 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
254 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
255 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
256 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
257 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
258 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
259 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
260 (('~fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
261 # Division and reciprocal
262 (('~fdiv', 1.0, a), ('frcp', a)),
263 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
264 (('~frcp', ('frcp', a)), a),
265 (('~frcp', ('fsqrt', a)), ('frsq', a)),
266 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
267 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
268 # Boolean simplifications
269 (('ieq', 'a@bool', True), a),
270 (('ine(is_not_used_by_if)', 'a@bool', True), ('inot', a)),
271 (('ine', 'a@bool', False), a),
272 (('ieq(is_not_used_by_if)', 'a@bool', False), ('inot', 'a')),
273 (('bcsel', a, True, False), a),
274 (('bcsel', a, False, True), ('inot', a)),
275 (('bcsel@32', a, 1.0, 0.0), ('b2f', a)),
276 (('bcsel@32', a, 0.0, 1.0), ('b2f', ('inot', a))),
277 (('bcsel@32', a, -1.0, -0.0), ('fneg', ('b2f', a))),
278 (('bcsel@32', a, -0.0, -1.0), ('fneg', ('b2f', ('inot', a)))),
279 (('bcsel', True, b, c), b),
280 (('bcsel', False, b, c), c),
281 # The result of this should be hit by constant propagation and, in the
282 # next round of opt_algebraic, get picked up by one of the above two.
283 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
284
285 (('bcsel', a, b, b), b),
286 (('fcsel', a, b, b), b),
287
288 # Conversions
289 (('i2b', ('b2i', a)), a),
290 (('f2i', ('ftrunc', a)), ('f2i', a)),
291 (('f2u', ('ftrunc', a)), ('f2u', a)),
292 (('i2b', ('ineg', a)), ('i2b', a)),
293 (('i2b', ('iabs', a)), ('i2b', a)),
294 (('fabs', ('b2f', a)), ('b2f', a)),
295 (('iabs', ('b2i', a)), ('b2i', a)),
296
297 # Byte extraction
298 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
299 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
300 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
301 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
302
303 # Word extraction
304 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
305 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
306
307 # Subtracts
308 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
309 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
310 (('ussub_4x8', a, 0), a),
311 (('ussub_4x8', a, ~0), 0),
312 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
313 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
314 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
315 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
316 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
317 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
318 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
319 (('iabs', ('isub', 0, a)), ('iabs', a)),
320
321 # Propagate negation up multiplication chains
322 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
323 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
324
325 # Reassociate constants in add/mul chains so they can be folded together.
326 # For now, we only handle cases where the constants are separated by
327 # a single non-constant. We could do better eventually.
328 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
329 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
330 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
331 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
332
333 # Misc. lowering
334 (('fmod@32', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod32'),
335 (('fmod@64', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod64'),
336 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod32'),
337 (('uadd_carry@32', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
338 (('usub_borrow@32', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
339
340 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
341 ('bcsel', ('ilt', 31, 'bits'), 'insert',
342 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
343 'options->lower_bitfield_insert'),
344
345 (('ibitfield_extract', 'value', 'offset', 'bits'),
346 ('bcsel', ('ilt', 31, 'bits'), 'value',
347 ('ibfe', 'value', 'offset', 'bits')),
348 'options->lower_bitfield_extract'),
349
350 (('ubitfield_extract', 'value', 'offset', 'bits'),
351 ('bcsel', ('ult', 31, 'bits'), 'value',
352 ('ubfe', 'value', 'offset', 'bits')),
353 'options->lower_bitfield_extract'),
354
355 (('extract_i8', a, b),
356 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
357 'options->lower_extract_byte'),
358
359 (('extract_u8', a, b),
360 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
361 'options->lower_extract_byte'),
362
363 (('extract_i16', a, b),
364 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
365 'options->lower_extract_word'),
366
367 (('extract_u16', a, b),
368 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
369 'options->lower_extract_word'),
370
371 (('pack_unorm_2x16', 'v'),
372 ('pack_uvec2_to_uint',
373 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
374 'options->lower_pack_unorm_2x16'),
375
376 (('pack_unorm_4x8', 'v'),
377 ('pack_uvec4_to_uint',
378 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
379 'options->lower_pack_unorm_4x8'),
380
381 (('pack_snorm_2x16', 'v'),
382 ('pack_uvec2_to_uint',
383 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
384 'options->lower_pack_snorm_2x16'),
385
386 (('pack_snorm_4x8', 'v'),
387 ('pack_uvec4_to_uint',
388 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
389 'options->lower_pack_snorm_4x8'),
390
391 (('unpack_unorm_2x16', 'v'),
392 ('fdiv', ('u2f', ('vec2', ('extract_u16', 'v', 0),
393 ('extract_u16', 'v', 1))),
394 65535.0),
395 'options->lower_unpack_unorm_2x16'),
396
397 (('unpack_unorm_4x8', 'v'),
398 ('fdiv', ('u2f', ('vec4', ('extract_u8', 'v', 0),
399 ('extract_u8', 'v', 1),
400 ('extract_u8', 'v', 2),
401 ('extract_u8', 'v', 3))),
402 255.0),
403 'options->lower_unpack_unorm_4x8'),
404
405 (('unpack_snorm_2x16', 'v'),
406 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec2', ('extract_i16', 'v', 0),
407 ('extract_i16', 'v', 1))),
408 32767.0))),
409 'options->lower_unpack_snorm_2x16'),
410
411 (('unpack_snorm_4x8', 'v'),
412 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec4', ('extract_i8', 'v', 0),
413 ('extract_i8', 'v', 1),
414 ('extract_i8', 'v', 2),
415 ('extract_i8', 'v', 3))),
416 127.0))),
417 'options->lower_unpack_snorm_4x8'),
418 ]
419
420 def fexp2i(exp, bits):
421 # We assume that exp is already in the right range.
422 if bits == 32:
423 return ('ishl', ('iadd', exp, 127), 23)
424 elif bits == 64:
425 return ('pack_double_2x32_split', 0, ('ishl', ('iadd', exp, 1023), 20))
426 else:
427 assert False
428
429 def ldexp(f, exp, bits):
430 # First, we clamp exp to a reasonable range. The maximum possible range
431 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
432 # a maximum range of [-149, 127]. This means that we can potentially have
433 # a swing of +-276. If you start with FLT_MAX, you actually have to do
434 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
435 # spec, on the other hand, only requires that we handle an exponent value
436 # in the range [-126, 128]. This implementation is *mostly* correct; it
437 # handles a range on exp of [-252, 254] which allows you to create any
438 # value (including denorms if the hardware supports it) and to adjust the
439 # exponent of any normal value to anything you want.
440 if bits == 32:
441 exp = ('imin', ('imax', exp, -252), 254)
442 elif bits == 64:
443 exp = ('imin', ('imax', exp, -2044), 2046)
444 else:
445 assert False
446
447 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
448 # (We use ishr which isn't the same for -1, but the -1 case still works
449 # since we use exp-exp/2 as the second exponent.) While the spec
450 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
451 # work with denormals and doesn't allow for the full swing in exponents
452 # that you can get with normalized values. Instead, we create two powers
453 # of two and multiply by them each in turn. That way the effective range
454 # of our exponent is doubled.
455 pow2_1 = fexp2i(('ishr', exp, 1), bits)
456 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)), bits)
457 return ('fmul', ('fmul', f, pow2_1), pow2_2)
458
459 optimizations += [
460 (('ldexp@32', 'x', 'exp'), ldexp('x', 'exp', 32)),
461 (('ldexp@64', 'x', 'exp'), ldexp('x', 'exp', 64)),
462 ]
463
464 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
465 def bitfield_reverse(u):
466 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
467 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
468 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
469 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
470 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
471
472 return step5
473
474 optimizations += [(bitfield_reverse('x@32'), ('bitfield_reverse', 'x'))]
475
476 # For any float comparison operation, "cmp", if you have "a == a && a cmp b"
477 # then the "a == a" is redundant because it's equivalent to "a is not NaN"
478 # and, if a is a NaN then the second comparison will fail anyway.
479 for op in ['flt', 'fge', 'feq']:
480 optimizations += [
481 (('iand', ('feq', a, a), (op, a, b)), (op, a, b)),
482 (('iand', ('feq', a, a), (op, b, a)), (op, b, a)),
483 ]
484
485 # Add optimizations to handle the case where the result of a ternary is
486 # compared to a constant. This way we can take things like
487 #
488 # (a ? 0 : 1) > 0
489 #
490 # and turn it into
491 #
492 # a ? (0 > 0) : (1 > 0)
493 #
494 # which constant folding will eat for lunch. The resulting ternary will
495 # further get cleaned up by the boolean reductions above and we will be
496 # left with just the original variable "a".
497 for op in ['flt', 'fge', 'feq', 'fne',
498 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
499 optimizations += [
500 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
501 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
502 ((op, '#d', ('bcsel', a, '#b', '#c')),
503 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
504 ]
505
506 # This section contains "late" optimizations that should be run after the
507 # regular optimizations have finished. Optimizations should go here if
508 # they help code generation but do not necessarily produce code that is
509 # more easily optimizable.
510 late_optimizations = [
511 # Most of these optimizations aren't quite safe when you get infinity or
512 # Nan involved but the first one should be fine.
513 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
514 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
515 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
516 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
517
518 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
519 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
520 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
521 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
522
523 (('b2f(is_used_more_than_once)', ('inot', a)), ('bcsel', a, 0.0, 1.0)),
524 (('fneg(is_used_more_than_once)', ('b2f', ('inot', a))), ('bcsel', a, -0.0, -1.0)),
525 ]
526
527 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
528 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
529 late_optimizations).render()