3cc910a8a606c97f044d5cf80ea0d7b79a68ab10
[mesa.git] / src / compiler / nir / nir_opt_algebraic.py
1 #
2 # Copyright (C) 2014 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 # Authors:
24 # Jason Ekstrand (jason@jlekstrand.net)
25
26 import nir_algebraic
27
28 # Convenience variables
29 a = 'a'
30 b = 'b'
31 c = 'c'
32 d = 'd'
33
34 # Written in the form (<search>, <replace>) where <search> is an expression
35 # and <replace> is either an expression or a value. An expression is
36 # defined as a tuple of the form ([~]<op>, <src0>, <src1>, <src2>, <src3>)
37 # where each source is either an expression or a value. A value can be
38 # either a numeric constant or a string representing a variable name.
39 #
40 # If the opcode in a search expression is prefixed by a '~' character, this
41 # indicates that the operation is inexact. Such operations will only get
42 # applied to SSA values that do not have the exact bit set. This should be
43 # used by by any optimizations that are not bit-for-bit exact. It should not,
44 # however, be used for backend-requested lowering operations as those need to
45 # happen regardless of precision.
46 #
47 # Variable names are specified as "[#]name[@type][(cond)]" where "#" inicates
48 # that the given variable will only match constants and the type indicates that
49 # the given variable will only match values from ALU instructions with the
50 # given output type, and (cond) specifies an additional condition function
51 # (see nir_search_helpers.h).
52 #
53 # For constants, you have to be careful to make sure that it is the right
54 # type because python is unaware of the source and destination types of the
55 # opcodes.
56 #
57 # All expression types can have a bit-size specified. For opcodes, this
58 # looks like "op@32", for variables it is "a@32" or "a@uint32" to specify a
59 # type and size, and for literals, you can write "2.0@32". In the search half
60 # of the expression this indicates that it should only match that particular
61 # bit-size. In the replace half of the expression this indicates that the
62 # constructed value should have that bit-size.
63
64 optimizations = [
65
66 (('imul', a, '#b@32(is_pos_power_of_two)'), ('ishl', a, ('find_lsb', b))),
67 (('imul', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('ishl', a, ('find_lsb', ('iabs', b))))),
68 (('udiv', a, 1), a),
69 (('idiv', a, 1), a),
70 (('umod', a, 1), 0),
71 (('imod', a, 1), 0),
72 (('udiv', a, '#b@32(is_pos_power_of_two)'), ('ushr', a, ('find_lsb', b))),
73 (('idiv', a, '#b@32(is_pos_power_of_two)'), ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', b))), 'options->lower_idiv'),
74 (('idiv', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', ('iabs', b))))), 'options->lower_idiv'),
75 (('umod', a, '#b(is_pos_power_of_two)'), ('iand', a, ('isub', b, 1))),
76
77 (('fneg', ('fneg', a)), a),
78 (('ineg', ('ineg', a)), a),
79 (('fabs', ('fabs', a)), ('fabs', a)),
80 (('fabs', ('fneg', a)), ('fabs', a)),
81 (('fabs', ('u2f32', a)), ('u2f32', a)),
82 (('iabs', ('iabs', a)), ('iabs', a)),
83 (('iabs', ('ineg', a)), ('iabs', a)),
84 (('~fadd', a, 0.0), a),
85 (('iadd', a, 0), a),
86 (('usadd_4x8', a, 0), a),
87 (('usadd_4x8', a, ~0), ~0),
88 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
89 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
90 (('~fadd', ('fneg', a), a), 0.0),
91 (('iadd', ('ineg', a), a), 0),
92 (('iadd', ('ineg', a), ('iadd', a, b)), b),
93 (('iadd', a, ('iadd', ('ineg', a), b)), b),
94 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
95 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
96 (('~fmul', a, 0.0), 0.0),
97 (('imul', a, 0), 0),
98 (('umul_unorm_4x8', a, 0), 0),
99 (('umul_unorm_4x8', a, ~0), a),
100 (('fmul', a, 1.0), a),
101 (('imul', a, 1), a),
102 (('fmul', a, -1.0), ('fneg', a)),
103 (('imul', a, -1), ('ineg', a)),
104 (('~ffma', 0.0, a, b), b),
105 (('~ffma', a, 0.0, b), b),
106 (('~ffma', a, b, 0.0), ('fmul', a, b)),
107 (('ffma', a, 1.0, b), ('fadd', a, b)),
108 (('ffma', 1.0, a, b), ('fadd', a, b)),
109 (('~flrp', a, b, 0.0), a),
110 (('~flrp', a, b, 1.0), b),
111 (('~flrp', a, a, b), a),
112 (('~flrp', 0.0, a, b), ('fmul', a, b)),
113 (('~flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp32'),
114 (('~flrp', a, 0.0, c), ('fadd', ('fmul', ('fneg', a), c), a)),
115 (('flrp@32', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp32'),
116 (('flrp@64', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp64'),
117 (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'),
118 (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp32'),
119 (('~fadd@32', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp32'),
120 (('~fadd@64', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp64'),
121 (('~fadd', a, ('fmul', ('b2f', c), ('fadd', b, ('fneg', a)))), ('bcsel', c, b, a), 'options->lower_flrp32'),
122 (('~fadd@32', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp32'),
123 (('~fadd@64', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp64'),
124 (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'),
125 (('~fadd', ('fmul', a, b), c), ('ffma', a, b, c), 'options->fuse_ffma'),
126
127 # (a * #b + #c) << #d
128 # ((a * #b) << #d) + (#c << #d)
129 # (a * (#b << #d)) + (#c << #d)
130 (('ishl', ('iadd', ('imul', a, '#b'), '#c'), '#d'),
131 ('iadd', ('imul', a, ('ishl', b, d)), ('ishl', c, d))),
132
133 # (a * #b) << #c
134 # a * (#b << #c)
135 (('ishl', ('imul', a, '#b'), '#c'), ('imul', a, ('ishl', b, c))),
136
137 # Comparison simplifications
138 (('~inot', ('flt', a, b)), ('fge', a, b)),
139 (('~inot', ('fge', a, b)), ('flt', a, b)),
140 (('~inot', ('feq', a, b)), ('fne', a, b)),
141 (('~inot', ('fne', a, b)), ('feq', a, b)),
142 (('inot', ('ilt', a, b)), ('ige', a, b)),
143 (('inot', ('ige', a, b)), ('ilt', a, b)),
144 (('inot', ('ieq', a, b)), ('ine', a, b)),
145 (('inot', ('ine', a, b)), ('ieq', a, b)),
146
147 # 0.0 >= b2f(a)
148 # b2f(a) <= 0.0
149 # b2f(a) == 0.0 because b2f(a) can only be 0 or 1
150 # inot(a)
151 (('fge', 0.0, ('b2f', a)), ('inot', a)),
152
153 (('fge', ('fneg', ('b2f', a)), 0.0), ('inot', a)),
154
155 # 0.0 < fabs(a)
156 # fabs(a) > 0.0
157 # fabs(a) != 0.0 because fabs(a) must be >= 0
158 # a != 0.0
159 (('flt', 0.0, ('fabs', a)), ('fne', a, 0.0)),
160
161 (('fmax', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('ior', a, b))),
162 (('fmax', ('fneg(is_used_once)', ('b2f(is_used_once)', a)), ('fneg', ('b2f', b))), ('fneg', ('b2f', ('ior', a, b)))),
163 (('fmin', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('iand', a, b))),
164 (('fmin', ('fneg(is_used_once)', ('b2f(is_used_once)', a)), ('fneg', ('b2f', b))), ('fneg', ('b2f', ('iand', a, b)))),
165
166 # ignore this opt when the result is used by a bcsel or if so we can make
167 # use of conditional modifiers on supported hardware.
168 (('flt(is_not_used_by_conditional)', ('fadd(is_used_once)', a, ('fneg', b)), 0.0), ('flt', a, b)),
169
170 (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
171 (('bcsel', ('flt', b, a), b, a), ('fmin', a, b)),
172 (('bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
173 (('bcsel', ('inot', a), b, c), ('bcsel', a, c, b)),
174 (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
175 (('bcsel', a, True, 'b@bool'), ('ior', a, b)),
176 (('fmin', a, a), a),
177 (('fmax', a, a), a),
178 (('imin', a, a), a),
179 (('imax', a, a), a),
180 (('umin', a, a), a),
181 (('umax', a, a), a),
182 (('fmin', a, ('fneg', a)), ('fneg', ('fabs', a))),
183 (('imin', a, ('ineg', a)), ('ineg', ('iabs', a))),
184 (('fmin', a, ('fneg', ('fabs', a))), ('fneg', ('fabs', a))),
185 (('imin', a, ('ineg', ('iabs', a))), ('ineg', ('iabs', a))),
186 (('fmin', a, ('fabs', a)), a),
187 (('imin', a, ('iabs', a)), a),
188 (('fmax', a, ('fneg', ('fabs', a))), a),
189 (('imax', a, ('ineg', ('iabs', a))), a),
190 (('fmax', a, ('fabs', a)), ('fabs', a)),
191 (('imax', a, ('iabs', a)), ('iabs', a)),
192 (('fmax', a, ('fneg', a)), ('fabs', a)),
193 (('imax', a, ('ineg', a)), ('iabs', a)),
194 (('~fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
195 (('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
196 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
197 (('fsat', ('fsat', a)), ('fsat', a)),
198 (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
199 (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
200 (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
201 (('fmax', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmax', a, b))),
202 (('fmin', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmin', a, b))),
203 (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
204 (('~ior', ('flt(is_used_once)', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
205 (('~ior', ('flt(is_used_once)', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
206 (('~ior', ('fge(is_used_once)', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
207 (('~ior', ('fge(is_used_once)', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
208 (('~ior', ('flt', a, '#b'), ('flt', a, '#c')), ('flt', a, ('fmax', b, c))),
209 (('~ior', ('flt', '#a', c), ('flt', '#b', c)), ('flt', ('fmin', a, b), c)),
210 (('~ior', ('fge', a, '#b'), ('fge', a, '#c')), ('fge', a, ('fmin', b, c))),
211 (('~ior', ('fge', '#a', c), ('fge', '#b', c)), ('fge', ('fmax', a, b), c)),
212 (('~iand', ('flt(is_used_once)', a, b), ('flt', a, c)), ('flt', a, ('fmin', b, c))),
213 (('~iand', ('flt(is_used_once)', a, c), ('flt', b, c)), ('flt', ('fmax', a, b), c)),
214 (('~iand', ('fge(is_used_once)', a, b), ('fge', a, c)), ('fge', a, ('fmax', b, c))),
215 (('~iand', ('fge(is_used_once)', a, c), ('fge', b, c)), ('fge', ('fmin', a, b), c)),
216 (('~iand', ('flt', a, '#b'), ('flt', a, '#c')), ('flt', a, ('fmin', b, c))),
217 (('~iand', ('flt', '#a', c), ('flt', '#b', c)), ('flt', ('fmax', a, b), c)),
218 (('~iand', ('fge', a, '#b'), ('fge', a, '#c')), ('fge', a, ('fmax', b, c))),
219 (('~iand', ('fge', '#a', c), ('fge', '#b', c)), ('fge', ('fmin', a, b), c)),
220
221 (('ior', ('ilt(is_used_once)', a, b), ('ilt', a, c)), ('ilt', a, ('imax', b, c))),
222 (('ior', ('ilt(is_used_once)', a, c), ('ilt', b, c)), ('ilt', ('imin', a, b), c)),
223 (('ior', ('ige(is_used_once)', a, b), ('ige', a, c)), ('ige', a, ('imin', b, c))),
224 (('ior', ('ige(is_used_once)', a, c), ('ige', b, c)), ('ige', ('imax', a, b), c)),
225 (('ior', ('ult(is_used_once)', a, b), ('ult', a, c)), ('ult', a, ('umax', b, c))),
226 (('ior', ('ult(is_used_once)', a, c), ('ult', b, c)), ('ult', ('umin', a, b), c)),
227 (('ior', ('uge(is_used_once)', a, b), ('uge', a, c)), ('uge', a, ('umin', b, c))),
228 (('ior', ('uge(is_used_once)', a, c), ('uge', b, c)), ('uge', ('umax', a, b), c)),
229 (('iand', ('ilt(is_used_once)', a, b), ('ilt', a, c)), ('ilt', a, ('imin', b, c))),
230 (('iand', ('ilt(is_used_once)', a, c), ('ilt', b, c)), ('ilt', ('imax', a, b), c)),
231 (('iand', ('ige(is_used_once)', a, b), ('ige', a, c)), ('ige', a, ('imax', b, c))),
232 (('iand', ('ige(is_used_once)', a, c), ('ige', b, c)), ('ige', ('imin', a, b), c)),
233 (('iand', ('ult(is_used_once)', a, b), ('ult', a, c)), ('ult', a, ('umin', b, c))),
234 (('iand', ('ult(is_used_once)', a, c), ('ult', b, c)), ('ult', ('umax', a, b), c)),
235 (('iand', ('uge(is_used_once)', a, b), ('uge', a, c)), ('uge', a, ('umax', b, c))),
236 (('iand', ('uge(is_used_once)', a, c), ('uge', b, c)), ('uge', ('umin', a, b), c)),
237
238 # These patterns can result when (a < b || a < c) => (a < min(b, c))
239 # transformations occur before constant propagation and loop-unrolling.
240 (('~flt', a, ('fmax', b, a)), ('flt', a, b)),
241 (('~flt', ('fmin', a, b), a), ('flt', b, a)),
242 (('~fge', a, ('fmin', b, a)), True),
243 (('~fge', ('fmax', a, b), a), True),
244 (('~flt', a, ('fmin', b, a)), False),
245 (('~flt', ('fmax', a, b), a), False),
246
247 (('ilt', a, ('imax', b, a)), ('ilt', a, b)),
248 (('ilt', ('imin', a, b), a), ('ilt', b, a)),
249 (('ige', a, ('imin', b, a)), True),
250 (('ige', ('imax', a, b), a), True),
251 (('ult', a, ('umax', b, a)), ('ult', a, b)),
252 (('ult', ('umin', a, b), a), ('ult', b, a)),
253 (('uge', a, ('umin', b, a)), True),
254 (('uge', ('umax', a, b), a), True),
255
256 (('ilt', '#a', ('imin', '#b', c)), ('iand', ('ilt', a, b), ('ilt', a, c))),
257 (('ilt', ('imax', '#a', b), '#c'), ('iand', ('ilt', a, c), ('ilt', b, c))),
258 (('ige', '#a', ('imax', '#b', c)), ('iand', ('ige', a, b), ('ige', a, c))),
259 (('ige', ('imin', '#a', b), '#c'), ('iand', ('ige', a, c), ('ige', b, c))),
260 (('ult', '#a', ('umin', '#b', c)), ('iand', ('ult', a, b), ('ult', a, c))),
261 (('ult', ('umax', '#a', b), '#c'), ('iand', ('ult', a, c), ('ult', b, c))),
262 (('uge', '#a', ('umax', '#b', c)), ('iand', ('uge', a, b), ('uge', a, c))),
263 (('uge', ('umin', '#a', b), '#c'), ('iand', ('uge', a, c), ('uge', b, c))),
264
265 (('fabs', ('slt', a, b)), ('slt', a, b)),
266 (('fabs', ('sge', a, b)), ('sge', a, b)),
267 (('fabs', ('seq', a, b)), ('seq', a, b)),
268 (('fabs', ('sne', a, b)), ('sne', a, b)),
269 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
270 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
271 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
272 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
273 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
274 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
275 # Emulating booleans
276 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
277 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
278 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
279 (('iand', 'a@bool', 1.0), ('b2f', a)),
280 # True/False are ~0 and 0 in NIR. b2i of True is 1, and -1 is ~0 (True).
281 (('ineg', ('b2i@32', a)), a),
282 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
283 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
284 # Comparison with the same args. Note that these are not done for
285 # the float versions because NaN always returns false on float
286 # inequalities.
287 (('ilt', a, a), False),
288 (('ige', a, a), True),
289 (('ieq', a, a), True),
290 (('ine', a, a), False),
291 (('ult', a, a), False),
292 (('uge', a, a), True),
293 # Logical and bit operations
294 (('fand', a, 0.0), 0.0),
295 (('iand', a, a), a),
296 (('iand', a, ~0), a),
297 (('iand', a, 0), 0),
298 (('ior', a, a), a),
299 (('ior', a, 0), a),
300 (('ior', a, True), True),
301 (('fxor', a, a), 0.0),
302 (('ixor', a, a), 0),
303 (('ixor', a, 0), a),
304 (('inot', ('inot', a)), a),
305 # DeMorgan's Laws
306 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
307 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
308 # Shift optimizations
309 (('ishl', 0, a), 0),
310 (('ishl', a, 0), a),
311 (('ishr', 0, a), 0),
312 (('ishr', a, 0), a),
313 (('ushr', 0, a), 0),
314 (('ushr', a, 0), a),
315 (('iand', 0xff, ('ushr@32', a, 24)), ('ushr', a, 24)),
316 (('iand', 0xffff, ('ushr@32', a, 16)), ('ushr', a, 16)),
317 # Exponential/logarithmic identities
318 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
319 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
320 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
321 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
322 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
323 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
324 (('~fpow', a, 1.0), a),
325 (('~fpow', a, 2.0), ('fmul', a, a)),
326 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
327 (('~fpow', 2.0, a), ('fexp2', a)),
328 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
329 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
330 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
331 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
332 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
333 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
334 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
335 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
336 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
337 (('~fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
338 # Division and reciprocal
339 (('~fdiv', 1.0, a), ('frcp', a)),
340 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
341 (('~frcp', ('frcp', a)), a),
342 (('~frcp', ('fsqrt', a)), ('frsq', a)),
343 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
344 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
345 # Boolean simplifications
346 (('ieq', 'a@bool', True), a),
347 (('ine(is_not_used_by_if)', 'a@bool', True), ('inot', a)),
348 (('ine', 'a@bool', False), a),
349 (('ieq(is_not_used_by_if)', 'a@bool', False), ('inot', 'a')),
350 (('bcsel', a, True, False), a),
351 (('bcsel', a, False, True), ('inot', a)),
352 (('bcsel@32', a, 1.0, 0.0), ('b2f', a)),
353 (('bcsel@32', a, 0.0, 1.0), ('b2f', ('inot', a))),
354 (('bcsel@32', a, -1.0, -0.0), ('fneg', ('b2f', a))),
355 (('bcsel@32', a, -0.0, -1.0), ('fneg', ('b2f', ('inot', a)))),
356 (('bcsel', True, b, c), b),
357 (('bcsel', False, b, c), c),
358 # The result of this should be hit by constant propagation and, in the
359 # next round of opt_algebraic, get picked up by one of the above two.
360 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
361
362 (('bcsel', a, b, b), b),
363 (('fcsel', a, b, b), b),
364
365 # Conversions
366 (('i2b', ('b2i', a)), a),
367 (('f2i32', ('ftrunc', a)), ('f2i32', a)),
368 (('f2u32', ('ftrunc', a)), ('f2u32', a)),
369 (('i2b', ('ineg', a)), ('i2b', a)),
370 (('i2b', ('iabs', a)), ('i2b', a)),
371 (('fabs', ('b2f', a)), ('b2f', a)),
372 (('iabs', ('b2i', a)), ('b2i', a)),
373
374 # Packing and then unpacking does nothing
375 (('unpack_64_2x32_split_x', ('pack_64_2x32_split', a, b)), a),
376 (('unpack_64_2x32_split_y', ('pack_64_2x32_split', a, b)), b),
377 (('pack_64_2x32_split', ('unpack_64_2x32_split_x', a),
378 ('unpack_64_2x32_split_y', a)), a),
379
380 # Byte extraction
381 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
382 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
383 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
384 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
385
386 # Word extraction
387 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
388 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
389
390 # Subtracts
391 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
392 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
393 (('ussub_4x8', a, 0), a),
394 (('ussub_4x8', a, ~0), 0),
395 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
396 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
397 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
398 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
399 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
400 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
401 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
402 (('iabs', ('isub', 0, a)), ('iabs', a)),
403
404 # Propagate negation up multiplication chains
405 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
406 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
407
408 # Propagate constants up multiplication chains
409 (('~fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fmul', ('fmul', a, c), b)),
410 (('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('imul', ('imul', a, c), b)),
411 (('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fadd', ('fadd', a, c), b)),
412 (('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('iadd', ('iadd', a, c), b)),
413
414 # Reassociate constants in add/mul chains so they can be folded together.
415 # For now, we mostly only handle cases where the constants are separated by
416 # a single non-constant. We could do better eventually.
417 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
418 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
419 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
420 (('~fadd', '#a', ('fneg', ('fadd', b, '#c'))), ('fadd', ('fadd', a, ('fneg', c)), ('fneg', b))),
421 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
422
423 # By definition...
424 (('bcsel', ('ige', ('find_lsb', a), 0), ('find_lsb', a), -1), ('find_lsb', a)),
425 (('bcsel', ('ige', ('ifind_msb', a), 0), ('ifind_msb', a), -1), ('ifind_msb', a)),
426 (('bcsel', ('ige', ('ufind_msb', a), 0), ('ufind_msb', a), -1), ('ufind_msb', a)),
427
428 (('bcsel', ('ine', a, 0), ('find_lsb', a), -1), ('find_lsb', a)),
429 (('bcsel', ('ine', a, 0), ('ifind_msb', a), -1), ('ifind_msb', a)),
430 (('bcsel', ('ine', a, 0), ('ufind_msb', a), -1), ('ufind_msb', a)),
431
432 (('bcsel', ('ine', a, -1), ('ifind_msb', a), -1), ('ifind_msb', a)),
433
434 # Misc. lowering
435 (('fmod@32', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod32'),
436 (('fmod@64', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod64'),
437 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod32'),
438 (('uadd_carry@32', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
439 (('usub_borrow@32', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
440
441 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
442 ('bcsel', ('ilt', 31, 'bits'), 'insert',
443 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
444 'options->lower_bitfield_insert'),
445
446 (('ibitfield_extract', 'value', 'offset', 'bits'),
447 ('bcsel', ('ilt', 31, 'bits'), 'value',
448 ('ibfe', 'value', 'offset', 'bits')),
449 'options->lower_bitfield_extract'),
450
451 (('ubitfield_extract', 'value', 'offset', 'bits'),
452 ('bcsel', ('ult', 31, 'bits'), 'value',
453 ('ubfe', 'value', 'offset', 'bits')),
454 'options->lower_bitfield_extract'),
455
456 (('extract_i8', a, 'b@32'),
457 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
458 'options->lower_extract_byte'),
459
460 (('extract_u8', a, 'b@32'),
461 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
462 'options->lower_extract_byte'),
463
464 (('extract_i16', a, 'b@32'),
465 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
466 'options->lower_extract_word'),
467
468 (('extract_u16', a, 'b@32'),
469 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
470 'options->lower_extract_word'),
471
472 (('pack_unorm_2x16', 'v'),
473 ('pack_uvec2_to_uint',
474 ('f2u32', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
475 'options->lower_pack_unorm_2x16'),
476
477 (('pack_unorm_4x8', 'v'),
478 ('pack_uvec4_to_uint',
479 ('f2u32', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
480 'options->lower_pack_unorm_4x8'),
481
482 (('pack_snorm_2x16', 'v'),
483 ('pack_uvec2_to_uint',
484 ('f2i32', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
485 'options->lower_pack_snorm_2x16'),
486
487 (('pack_snorm_4x8', 'v'),
488 ('pack_uvec4_to_uint',
489 ('f2i32', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
490 'options->lower_pack_snorm_4x8'),
491
492 (('unpack_unorm_2x16', 'v'),
493 ('fdiv', ('u2f32', ('vec2', ('extract_u16', 'v', 0),
494 ('extract_u16', 'v', 1))),
495 65535.0),
496 'options->lower_unpack_unorm_2x16'),
497
498 (('unpack_unorm_4x8', 'v'),
499 ('fdiv', ('u2f32', ('vec4', ('extract_u8', 'v', 0),
500 ('extract_u8', 'v', 1),
501 ('extract_u8', 'v', 2),
502 ('extract_u8', 'v', 3))),
503 255.0),
504 'options->lower_unpack_unorm_4x8'),
505
506 (('unpack_snorm_2x16', 'v'),
507 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f32', ('vec2', ('extract_i16', 'v', 0),
508 ('extract_i16', 'v', 1))),
509 32767.0))),
510 'options->lower_unpack_snorm_2x16'),
511
512 (('unpack_snorm_4x8', 'v'),
513 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f32', ('vec4', ('extract_i8', 'v', 0),
514 ('extract_i8', 'v', 1),
515 ('extract_i8', 'v', 2),
516 ('extract_i8', 'v', 3))),
517 127.0))),
518 'options->lower_unpack_snorm_4x8'),
519 ]
520
521 def fexp2i(exp, bits):
522 # We assume that exp is already in the right range.
523 if bits == 32:
524 return ('ishl', ('iadd', exp, 127), 23)
525 elif bits == 64:
526 return ('pack_64_2x32_split', 0, ('ishl', ('iadd', exp, 1023), 20))
527 else:
528 assert False
529
530 def ldexp(f, exp, bits):
531 # First, we clamp exp to a reasonable range. The maximum possible range
532 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
533 # a maximum range of [-149, 127]. This means that we can potentially have
534 # a swing of +-276. If you start with FLT_MAX, you actually have to do
535 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
536 # spec, on the other hand, only requires that we handle an exponent value
537 # in the range [-126, 128]. This implementation is *mostly* correct; it
538 # handles a range on exp of [-252, 254] which allows you to create any
539 # value (including denorms if the hardware supports it) and to adjust the
540 # exponent of any normal value to anything you want.
541 if bits == 32:
542 exp = ('imin', ('imax', exp, -252), 254)
543 elif bits == 64:
544 exp = ('imin', ('imax', exp, -2044), 2046)
545 else:
546 assert False
547
548 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
549 # (We use ishr which isn't the same for -1, but the -1 case still works
550 # since we use exp-exp/2 as the second exponent.) While the spec
551 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
552 # work with denormals and doesn't allow for the full swing in exponents
553 # that you can get with normalized values. Instead, we create two powers
554 # of two and multiply by them each in turn. That way the effective range
555 # of our exponent is doubled.
556 pow2_1 = fexp2i(('ishr', exp, 1), bits)
557 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)), bits)
558 return ('fmul', ('fmul', f, pow2_1), pow2_2)
559
560 optimizations += [
561 (('ldexp@32', 'x', 'exp'), ldexp('x', 'exp', 32)),
562 (('ldexp@64', 'x', 'exp'), ldexp('x', 'exp', 64)),
563 ]
564
565 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
566 def bitfield_reverse(u):
567 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
568 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
569 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
570 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
571 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
572
573 return step5
574
575 optimizations += [(bitfield_reverse('x@32'), ('bitfield_reverse', 'x'))]
576
577 # For any float comparison operation, "cmp", if you have "a == a && a cmp b"
578 # then the "a == a" is redundant because it's equivalent to "a is not NaN"
579 # and, if a is a NaN then the second comparison will fail anyway.
580 for op in ['flt', 'fge', 'feq']:
581 optimizations += [
582 (('iand', ('feq', a, a), (op, a, b)), (op, a, b)),
583 (('iand', ('feq', a, a), (op, b, a)), (op, b, a)),
584 ]
585
586 # Add optimizations to handle the case where the result of a ternary is
587 # compared to a constant. This way we can take things like
588 #
589 # (a ? 0 : 1) > 0
590 #
591 # and turn it into
592 #
593 # a ? (0 > 0) : (1 > 0)
594 #
595 # which constant folding will eat for lunch. The resulting ternary will
596 # further get cleaned up by the boolean reductions above and we will be
597 # left with just the original variable "a".
598 for op in ['flt', 'fge', 'feq', 'fne',
599 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
600 optimizations += [
601 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
602 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
603 ((op, '#d', ('bcsel', a, '#b', '#c')),
604 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
605 ]
606
607 # This section contains "late" optimizations that should be run before
608 # creating ffmas and calling regular optimizations for the final time.
609 # Optimizations should go here if they help code generation and conflict
610 # with the regular optimizations.
611 before_ffma_optimizations = [
612 # Propagate constants down multiplication chains
613 (('~fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fmul', ('fmul', a, c), b)),
614 (('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('imul', ('imul', a, c), b)),
615 (('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fadd', ('fadd', a, c), b)),
616 (('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('iadd', ('iadd', a, c), b)),
617
618 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
619 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
620 (('~fadd', ('fneg', a), a), 0.0),
621 (('iadd', ('ineg', a), a), 0),
622 (('iadd', ('ineg', a), ('iadd', a, b)), b),
623 (('iadd', a, ('iadd', ('ineg', a), b)), b),
624 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
625 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
626 ]
627
628 # This section contains "late" optimizations that should be run after the
629 # regular optimizations have finished. Optimizations should go here if
630 # they help code generation but do not necessarily produce code that is
631 # more easily optimizable.
632 late_optimizations = [
633 # Most of these optimizations aren't quite safe when you get infinity or
634 # Nan involved but the first one should be fine.
635 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
636 (('flt', ('fneg', ('fadd', a, b)), 0.0), ('flt', ('fneg', a), b)),
637 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
638 (('~fge', ('fneg', ('fadd', a, b)), 0.0), ('fge', ('fneg', a), b)),
639 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
640 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
641
642 (('~fge', ('fmin(is_used_once)', ('fadd(is_used_once)', a, b), ('fadd', c, d)), 0.0), ('iand', ('fge', a, ('fneg', b)), ('fge', c, ('fneg', d)))),
643
644 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
645 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
646 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
647 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
648
649 (('b2f(is_used_more_than_once)', ('inot', a)), ('bcsel', a, 0.0, 1.0)),
650 (('fneg(is_used_more_than_once)', ('b2f', ('inot', a))), ('bcsel', a, -0.0, -1.0)),
651
652 # we do these late so that we don't get in the way of creating ffmas
653 (('fmin', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmin', a, b))),
654 (('fmax', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmax', a, b))),
655 ]
656
657 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
658 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_before_ffma",
659 before_ffma_optimizations).render()
660 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
661 late_optimizations).render()