nir/algebraic: Optimize 64bit pack/unpack
[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', a, ('fneg', a)), ('fneg', ('fabs', a))),
175 (('imin', a, ('ineg', a)), ('ineg', ('iabs', a))),
176 (('fmin', a, ('fneg', ('fabs', a))), ('fneg', ('fabs', a))),
177 (('imin', a, ('ineg', ('iabs', a))), ('ineg', ('iabs', a))),
178 (('fmin', a, ('fabs', a)), a),
179 (('imin', a, ('iabs', a)), a),
180 (('fmax', a, ('fneg', ('fabs', a))), a),
181 (('imax', a, ('ineg', ('iabs', a))), a),
182 (('fmax', a, ('fabs', a)), ('fabs', a)),
183 (('imax', a, ('iabs', a)), ('iabs', a)),
184 (('fmax', a, ('fneg', a)), ('fabs', a)),
185 (('imax', a, ('ineg', a)), ('iabs', a)),
186 (('~fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
187 (('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
188 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
189 (('fsat', ('fsat', a)), ('fsat', a)),
190 (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
191 (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
192 (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
193 (('fmax', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmax', a, b))),
194 (('fmin', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmin', a, b))),
195 (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
196 (('~ior', ('flt', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
197 (('~ior', ('flt', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
198 (('~ior', ('fge', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
199 (('~ior', ('fge', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
200 (('fabs', ('slt', a, b)), ('slt', a, b)),
201 (('fabs', ('sge', a, b)), ('sge', a, b)),
202 (('fabs', ('seq', a, b)), ('seq', a, b)),
203 (('fabs', ('sne', a, b)), ('sne', a, b)),
204 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
205 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
206 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
207 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
208 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
209 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
210 # Emulating booleans
211 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
212 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
213 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
214 (('iand', 'a@bool', 1.0), ('b2f', a)),
215 # True/False are ~0 and 0 in NIR. b2i of True is 1, and -1 is ~0 (True).
216 (('ineg', ('b2i', a)), a),
217 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
218 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
219 # Comparison with the same args. Note that these are not done for
220 # the float versions because NaN always returns false on float
221 # inequalities.
222 (('ilt', a, a), False),
223 (('ige', a, a), True),
224 (('ieq', a, a), True),
225 (('ine', a, a), False),
226 (('ult', a, a), False),
227 (('uge', a, a), True),
228 # Logical and bit operations
229 (('fand', a, 0.0), 0.0),
230 (('iand', a, a), a),
231 (('iand', a, ~0), a),
232 (('iand', a, 0), 0),
233 (('ior', a, a), a),
234 (('ior', a, 0), a),
235 (('ior', a, True), True),
236 (('fxor', a, a), 0.0),
237 (('ixor', a, a), 0),
238 (('ixor', a, 0), a),
239 (('inot', ('inot', a)), a),
240 # DeMorgan's Laws
241 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
242 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
243 # Shift optimizations
244 (('ishl', 0, a), 0),
245 (('ishl', a, 0), a),
246 (('ishr', 0, a), 0),
247 (('ishr', a, 0), a),
248 (('ushr', 0, a), 0),
249 (('ushr', a, 0), a),
250 (('iand', 0xff, ('ushr', a, 24)), ('ushr', a, 24)),
251 (('iand', 0xffff, ('ushr', a, 16)), ('ushr', a, 16)),
252 # Exponential/logarithmic identities
253 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
254 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
255 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
256 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
257 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
258 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
259 (('~fpow', a, 1.0), a),
260 (('~fpow', a, 2.0), ('fmul', a, a)),
261 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
262 (('~fpow', 2.0, a), ('fexp2', a)),
263 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
264 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
265 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
266 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
267 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
268 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
269 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
270 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
271 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
272 (('~fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
273 # Division and reciprocal
274 (('~fdiv', 1.0, a), ('frcp', a)),
275 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
276 (('~frcp', ('frcp', a)), a),
277 (('~frcp', ('fsqrt', a)), ('frsq', a)),
278 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
279 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
280 # Boolean simplifications
281 (('ieq', 'a@bool', True), a),
282 (('ine(is_not_used_by_if)', 'a@bool', True), ('inot', a)),
283 (('ine', 'a@bool', False), a),
284 (('ieq(is_not_used_by_if)', 'a@bool', False), ('inot', 'a')),
285 (('bcsel', a, True, False), a),
286 (('bcsel', a, False, True), ('inot', a)),
287 (('bcsel@32', a, 1.0, 0.0), ('b2f', a)),
288 (('bcsel@32', a, 0.0, 1.0), ('b2f', ('inot', a))),
289 (('bcsel@32', a, -1.0, -0.0), ('fneg', ('b2f', a))),
290 (('bcsel@32', a, -0.0, -1.0), ('fneg', ('b2f', ('inot', a)))),
291 (('bcsel', True, b, c), b),
292 (('bcsel', False, b, c), c),
293 # The result of this should be hit by constant propagation and, in the
294 # next round of opt_algebraic, get picked up by one of the above two.
295 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
296
297 (('bcsel', a, b, b), b),
298 (('fcsel', a, b, b), b),
299
300 # Conversions
301 (('i2b', ('b2i', a)), a),
302 (('f2i', ('ftrunc', a)), ('f2i', a)),
303 (('f2u', ('ftrunc', a)), ('f2u', a)),
304 (('i2b', ('ineg', a)), ('i2b', a)),
305 (('i2b', ('iabs', a)), ('i2b', a)),
306 (('fabs', ('b2f', a)), ('b2f', a)),
307 (('iabs', ('b2i', a)), ('b2i', a)),
308
309 # Packing and then unpacking does nothing
310 (('unpack_64_2x32_split_x', ('pack_64_2x32_split', a, b)), a),
311 (('unpack_64_2x32_split_y', ('pack_64_2x32_split', a, b)), b),
312 (('pack_64_2x32_split', ('unpack_64_2x32_split_x', a),
313 ('unpack_64_2x32_split_y', a)), a),
314
315 # Byte extraction
316 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
317 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
318 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
319 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
320
321 # Word extraction
322 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
323 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
324
325 # Subtracts
326 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
327 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
328 (('ussub_4x8', a, 0), a),
329 (('ussub_4x8', a, ~0), 0),
330 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
331 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
332 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
333 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
334 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
335 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
336 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
337 (('iabs', ('isub', 0, a)), ('iabs', a)),
338
339 # Propagate negation up multiplication chains
340 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
341 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
342
343 # Reassociate constants in add/mul chains so they can be folded together.
344 # For now, we only handle cases where the constants are separated by
345 # a single non-constant. We could do better eventually.
346 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
347 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
348 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
349 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
350
351 # Misc. lowering
352 (('fmod@32', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod32'),
353 (('fmod@64', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod64'),
354 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod32'),
355 (('uadd_carry@32', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
356 (('usub_borrow@32', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
357
358 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
359 ('bcsel', ('ilt', 31, 'bits'), 'insert',
360 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
361 'options->lower_bitfield_insert'),
362
363 (('ibitfield_extract', 'value', 'offset', 'bits'),
364 ('bcsel', ('ilt', 31, 'bits'), 'value',
365 ('ibfe', 'value', 'offset', 'bits')),
366 'options->lower_bitfield_extract'),
367
368 (('ubitfield_extract', 'value', 'offset', 'bits'),
369 ('bcsel', ('ult', 31, 'bits'), 'value',
370 ('ubfe', 'value', 'offset', 'bits')),
371 'options->lower_bitfield_extract'),
372
373 (('extract_i8', a, 'b@32'),
374 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
375 'options->lower_extract_byte'),
376
377 (('extract_u8', a, 'b@32'),
378 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
379 'options->lower_extract_byte'),
380
381 (('extract_i16', a, 'b@32'),
382 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
383 'options->lower_extract_word'),
384
385 (('extract_u16', a, 'b@32'),
386 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
387 'options->lower_extract_word'),
388
389 (('pack_unorm_2x16', 'v'),
390 ('pack_uvec2_to_uint',
391 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
392 'options->lower_pack_unorm_2x16'),
393
394 (('pack_unorm_4x8', 'v'),
395 ('pack_uvec4_to_uint',
396 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
397 'options->lower_pack_unorm_4x8'),
398
399 (('pack_snorm_2x16', 'v'),
400 ('pack_uvec2_to_uint',
401 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
402 'options->lower_pack_snorm_2x16'),
403
404 (('pack_snorm_4x8', 'v'),
405 ('pack_uvec4_to_uint',
406 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
407 'options->lower_pack_snorm_4x8'),
408
409 (('unpack_unorm_2x16', 'v'),
410 ('fdiv', ('u2f', ('vec2', ('extract_u16', 'v', 0),
411 ('extract_u16', 'v', 1))),
412 65535.0),
413 'options->lower_unpack_unorm_2x16'),
414
415 (('unpack_unorm_4x8', 'v'),
416 ('fdiv', ('u2f', ('vec4', ('extract_u8', 'v', 0),
417 ('extract_u8', 'v', 1),
418 ('extract_u8', 'v', 2),
419 ('extract_u8', 'v', 3))),
420 255.0),
421 'options->lower_unpack_unorm_4x8'),
422
423 (('unpack_snorm_2x16', 'v'),
424 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec2', ('extract_i16', 'v', 0),
425 ('extract_i16', 'v', 1))),
426 32767.0))),
427 'options->lower_unpack_snorm_2x16'),
428
429 (('unpack_snorm_4x8', 'v'),
430 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec4', ('extract_i8', 'v', 0),
431 ('extract_i8', 'v', 1),
432 ('extract_i8', 'v', 2),
433 ('extract_i8', 'v', 3))),
434 127.0))),
435 'options->lower_unpack_snorm_4x8'),
436 ]
437
438 def fexp2i(exp, bits):
439 # We assume that exp is already in the right range.
440 if bits == 32:
441 return ('ishl', ('iadd', exp, 127), 23)
442 elif bits == 64:
443 return ('pack_64_2x32_split', 0, ('ishl', ('iadd', exp, 1023), 20))
444 else:
445 assert False
446
447 def ldexp(f, exp, bits):
448 # First, we clamp exp to a reasonable range. The maximum possible range
449 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
450 # a maximum range of [-149, 127]. This means that we can potentially have
451 # a swing of +-276. If you start with FLT_MAX, you actually have to do
452 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
453 # spec, on the other hand, only requires that we handle an exponent value
454 # in the range [-126, 128]. This implementation is *mostly* correct; it
455 # handles a range on exp of [-252, 254] which allows you to create any
456 # value (including denorms if the hardware supports it) and to adjust the
457 # exponent of any normal value to anything you want.
458 if bits == 32:
459 exp = ('imin', ('imax', exp, -252), 254)
460 elif bits == 64:
461 exp = ('imin', ('imax', exp, -2044), 2046)
462 else:
463 assert False
464
465 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
466 # (We use ishr which isn't the same for -1, but the -1 case still works
467 # since we use exp-exp/2 as the second exponent.) While the spec
468 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
469 # work with denormals and doesn't allow for the full swing in exponents
470 # that you can get with normalized values. Instead, we create two powers
471 # of two and multiply by them each in turn. That way the effective range
472 # of our exponent is doubled.
473 pow2_1 = fexp2i(('ishr', exp, 1), bits)
474 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)), bits)
475 return ('fmul', ('fmul', f, pow2_1), pow2_2)
476
477 optimizations += [
478 (('ldexp@32', 'x', 'exp'), ldexp('x', 'exp', 32)),
479 (('ldexp@64', 'x', 'exp'), ldexp('x', 'exp', 64)),
480 ]
481
482 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
483 def bitfield_reverse(u):
484 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
485 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
486 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
487 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
488 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
489
490 return step5
491
492 optimizations += [(bitfield_reverse('x@32'), ('bitfield_reverse', 'x'))]
493
494 # For any float comparison operation, "cmp", if you have "a == a && a cmp b"
495 # then the "a == a" is redundant because it's equivalent to "a is not NaN"
496 # and, if a is a NaN then the second comparison will fail anyway.
497 for op in ['flt', 'fge', 'feq']:
498 optimizations += [
499 (('iand', ('feq', a, a), (op, a, b)), (op, a, b)),
500 (('iand', ('feq', a, a), (op, b, a)), (op, b, a)),
501 ]
502
503 # Add optimizations to handle the case where the result of a ternary is
504 # compared to a constant. This way we can take things like
505 #
506 # (a ? 0 : 1) > 0
507 #
508 # and turn it into
509 #
510 # a ? (0 > 0) : (1 > 0)
511 #
512 # which constant folding will eat for lunch. The resulting ternary will
513 # further get cleaned up by the boolean reductions above and we will be
514 # left with just the original variable "a".
515 for op in ['flt', 'fge', 'feq', 'fne',
516 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
517 optimizations += [
518 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
519 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
520 ((op, '#d', ('bcsel', a, '#b', '#c')),
521 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
522 ]
523
524 # This section contains "late" optimizations that should be run after the
525 # regular optimizations have finished. Optimizations should go here if
526 # they help code generation but do not necessarily produce code that is
527 # more easily optimizable.
528 late_optimizations = [
529 # Most of these optimizations aren't quite safe when you get infinity or
530 # Nan involved but the first one should be fine.
531 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
532 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
533 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
534 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
535
536 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
537 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
538 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
539 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
540
541 (('b2f(is_used_more_than_once)', ('inot', a)), ('bcsel', a, 0.0, 1.0)),
542 (('fneg(is_used_more_than_once)', ('b2f', ('inot', a))), ('bcsel', a, -0.0, -1.0)),
543
544 # we do these late so that we don't get in the way of creating ffmas
545 (('fmin', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmin', a, b))),
546 (('fmax', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmax', a, b))),
547 ]
548
549 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
550 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
551 late_optimizations).render()