nir: Separate a weird compare with zero to two compares with zero
[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
213 # These patterns can result when (a < b || a < c) => (a < min(b, c))
214 # transformations occur before constant propagation and loop-unrolling.
215 (('~flt', a, ('fmax', b, a)), ('flt', a, b)),
216 (('~flt', ('fmin', a, b), a), ('flt', b, a)),
217 (('~fge', a, ('fmin', b, a)), True),
218 (('~fge', ('fmax', a, b), a), True),
219 (('~flt', a, ('fmin', b, a)), False),
220 (('~flt', ('fmax', a, b), a), False),
221
222 (('fabs', ('slt', a, b)), ('slt', a, b)),
223 (('fabs', ('sge', a, b)), ('sge', a, b)),
224 (('fabs', ('seq', a, b)), ('seq', a, b)),
225 (('fabs', ('sne', a, b)), ('sne', a, b)),
226 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
227 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
228 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
229 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
230 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
231 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
232 # Emulating booleans
233 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
234 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
235 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
236 (('iand', 'a@bool', 1.0), ('b2f', a)),
237 # True/False are ~0 and 0 in NIR. b2i of True is 1, and -1 is ~0 (True).
238 (('ineg', ('b2i@32', a)), a),
239 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
240 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
241 # Comparison with the same args. Note that these are not done for
242 # the float versions because NaN always returns false on float
243 # inequalities.
244 (('ilt', a, a), False),
245 (('ige', a, a), True),
246 (('ieq', a, a), True),
247 (('ine', a, a), False),
248 (('ult', a, a), False),
249 (('uge', a, a), True),
250 # Logical and bit operations
251 (('fand', a, 0.0), 0.0),
252 (('iand', a, a), a),
253 (('iand', a, ~0), a),
254 (('iand', a, 0), 0),
255 (('ior', a, a), a),
256 (('ior', a, 0), a),
257 (('ior', a, True), True),
258 (('fxor', a, a), 0.0),
259 (('ixor', a, a), 0),
260 (('ixor', a, 0), a),
261 (('inot', ('inot', a)), a),
262 # DeMorgan's Laws
263 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
264 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
265 # Shift optimizations
266 (('ishl', 0, a), 0),
267 (('ishl', a, 0), a),
268 (('ishr', 0, a), 0),
269 (('ishr', a, 0), a),
270 (('ushr', 0, a), 0),
271 (('ushr', a, 0), a),
272 (('iand', 0xff, ('ushr@32', a, 24)), ('ushr', a, 24)),
273 (('iand', 0xffff, ('ushr@32', a, 16)), ('ushr', a, 16)),
274 # Exponential/logarithmic identities
275 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
276 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
277 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
278 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
279 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
280 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
281 (('~fpow', a, 1.0), a),
282 (('~fpow', a, 2.0), ('fmul', a, a)),
283 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
284 (('~fpow', 2.0, a), ('fexp2', a)),
285 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
286 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
287 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
288 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
289 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
290 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
291 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
292 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
293 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
294 (('~fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
295 # Division and reciprocal
296 (('~fdiv', 1.0, a), ('frcp', a)),
297 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
298 (('~frcp', ('frcp', a)), a),
299 (('~frcp', ('fsqrt', a)), ('frsq', a)),
300 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
301 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
302 # Boolean simplifications
303 (('ieq', 'a@bool', True), a),
304 (('ine(is_not_used_by_if)', 'a@bool', True), ('inot', a)),
305 (('ine', 'a@bool', False), a),
306 (('ieq(is_not_used_by_if)', 'a@bool', False), ('inot', 'a')),
307 (('bcsel', a, True, False), a),
308 (('bcsel', a, False, True), ('inot', a)),
309 (('bcsel@32', a, 1.0, 0.0), ('b2f', a)),
310 (('bcsel@32', a, 0.0, 1.0), ('b2f', ('inot', a))),
311 (('bcsel@32', a, -1.0, -0.0), ('fneg', ('b2f', a))),
312 (('bcsel@32', a, -0.0, -1.0), ('fneg', ('b2f', ('inot', a)))),
313 (('bcsel', True, b, c), b),
314 (('bcsel', False, b, c), c),
315 # The result of this should be hit by constant propagation and, in the
316 # next round of opt_algebraic, get picked up by one of the above two.
317 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
318
319 (('bcsel', a, b, b), b),
320 (('fcsel', a, b, b), b),
321
322 # Conversions
323 (('i2b', ('b2i', a)), a),
324 (('f2i32', ('ftrunc', a)), ('f2i32', a)),
325 (('f2u32', ('ftrunc', a)), ('f2u32', a)),
326 (('i2b', ('ineg', a)), ('i2b', a)),
327 (('i2b', ('iabs', a)), ('i2b', a)),
328 (('fabs', ('b2f', a)), ('b2f', a)),
329 (('iabs', ('b2i', a)), ('b2i', a)),
330
331 # Packing and then unpacking does nothing
332 (('unpack_64_2x32_split_x', ('pack_64_2x32_split', a, b)), a),
333 (('unpack_64_2x32_split_y', ('pack_64_2x32_split', a, b)), b),
334 (('pack_64_2x32_split', ('unpack_64_2x32_split_x', a),
335 ('unpack_64_2x32_split_y', a)), a),
336
337 # Byte extraction
338 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
339 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
340 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
341 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
342
343 # Word extraction
344 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
345 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
346
347 # Subtracts
348 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
349 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
350 (('ussub_4x8', a, 0), a),
351 (('ussub_4x8', a, ~0), 0),
352 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
353 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
354 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
355 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
356 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
357 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
358 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
359 (('iabs', ('isub', 0, a)), ('iabs', a)),
360
361 # Propagate negation up multiplication chains
362 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
363 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
364
365 # Propagate constants up multiplication chains
366 (('~fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fmul', ('fmul', a, c), b)),
367 (('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('imul', ('imul', a, c), b)),
368 (('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fadd', ('fadd', a, c), b)),
369 (('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('iadd', ('iadd', a, c), b)),
370
371 # Reassociate constants in add/mul chains so they can be folded together.
372 # For now, we mostly only handle cases where the constants are separated by
373 # a single non-constant. We could do better eventually.
374 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
375 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
376 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
377 (('~fadd', '#a', ('fneg', ('fadd', b, '#c'))), ('fadd', ('fadd', a, ('fneg', c)), ('fneg', b))),
378 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
379
380 # By definition...
381 (('bcsel', ('ige', ('find_lsb', a), 0), ('find_lsb', a), -1), ('find_lsb', a)),
382 (('bcsel', ('ige', ('ifind_msb', a), 0), ('ifind_msb', a), -1), ('ifind_msb', a)),
383 (('bcsel', ('ige', ('ufind_msb', a), 0), ('ufind_msb', a), -1), ('ufind_msb', a)),
384
385 (('bcsel', ('ine', a, 0), ('find_lsb', a), -1), ('find_lsb', a)),
386 (('bcsel', ('ine', a, 0), ('ifind_msb', a), -1), ('ifind_msb', a)),
387 (('bcsel', ('ine', a, 0), ('ufind_msb', a), -1), ('ufind_msb', a)),
388
389 (('bcsel', ('ine', a, -1), ('ifind_msb', a), -1), ('ifind_msb', a)),
390
391 # Misc. lowering
392 (('fmod@32', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod32'),
393 (('fmod@64', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod64'),
394 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod32'),
395 (('uadd_carry@32', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
396 (('usub_borrow@32', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
397
398 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
399 ('bcsel', ('ilt', 31, 'bits'), 'insert',
400 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
401 'options->lower_bitfield_insert'),
402
403 (('ibitfield_extract', 'value', 'offset', 'bits'),
404 ('bcsel', ('ilt', 31, 'bits'), 'value',
405 ('ibfe', 'value', 'offset', 'bits')),
406 'options->lower_bitfield_extract'),
407
408 (('ubitfield_extract', 'value', 'offset', 'bits'),
409 ('bcsel', ('ult', 31, 'bits'), 'value',
410 ('ubfe', 'value', 'offset', 'bits')),
411 'options->lower_bitfield_extract'),
412
413 (('extract_i8', a, 'b@32'),
414 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
415 'options->lower_extract_byte'),
416
417 (('extract_u8', a, 'b@32'),
418 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
419 'options->lower_extract_byte'),
420
421 (('extract_i16', a, 'b@32'),
422 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
423 'options->lower_extract_word'),
424
425 (('extract_u16', a, 'b@32'),
426 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
427 'options->lower_extract_word'),
428
429 (('pack_unorm_2x16', 'v'),
430 ('pack_uvec2_to_uint',
431 ('f2u32', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
432 'options->lower_pack_unorm_2x16'),
433
434 (('pack_unorm_4x8', 'v'),
435 ('pack_uvec4_to_uint',
436 ('f2u32', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
437 'options->lower_pack_unorm_4x8'),
438
439 (('pack_snorm_2x16', 'v'),
440 ('pack_uvec2_to_uint',
441 ('f2i32', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
442 'options->lower_pack_snorm_2x16'),
443
444 (('pack_snorm_4x8', 'v'),
445 ('pack_uvec4_to_uint',
446 ('f2i32', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
447 'options->lower_pack_snorm_4x8'),
448
449 (('unpack_unorm_2x16', 'v'),
450 ('fdiv', ('u2f32', ('vec2', ('extract_u16', 'v', 0),
451 ('extract_u16', 'v', 1))),
452 65535.0),
453 'options->lower_unpack_unorm_2x16'),
454
455 (('unpack_unorm_4x8', 'v'),
456 ('fdiv', ('u2f32', ('vec4', ('extract_u8', 'v', 0),
457 ('extract_u8', 'v', 1),
458 ('extract_u8', 'v', 2),
459 ('extract_u8', 'v', 3))),
460 255.0),
461 'options->lower_unpack_unorm_4x8'),
462
463 (('unpack_snorm_2x16', 'v'),
464 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f32', ('vec2', ('extract_i16', 'v', 0),
465 ('extract_i16', 'v', 1))),
466 32767.0))),
467 'options->lower_unpack_snorm_2x16'),
468
469 (('unpack_snorm_4x8', 'v'),
470 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f32', ('vec4', ('extract_i8', 'v', 0),
471 ('extract_i8', 'v', 1),
472 ('extract_i8', 'v', 2),
473 ('extract_i8', 'v', 3))),
474 127.0))),
475 'options->lower_unpack_snorm_4x8'),
476 ]
477
478 def fexp2i(exp, bits):
479 # We assume that exp is already in the right range.
480 if bits == 32:
481 return ('ishl', ('iadd', exp, 127), 23)
482 elif bits == 64:
483 return ('pack_64_2x32_split', 0, ('ishl', ('iadd', exp, 1023), 20))
484 else:
485 assert False
486
487 def ldexp(f, exp, bits):
488 # First, we clamp exp to a reasonable range. The maximum possible range
489 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
490 # a maximum range of [-149, 127]. This means that we can potentially have
491 # a swing of +-276. If you start with FLT_MAX, you actually have to do
492 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
493 # spec, on the other hand, only requires that we handle an exponent value
494 # in the range [-126, 128]. This implementation is *mostly* correct; it
495 # handles a range on exp of [-252, 254] which allows you to create any
496 # value (including denorms if the hardware supports it) and to adjust the
497 # exponent of any normal value to anything you want.
498 if bits == 32:
499 exp = ('imin', ('imax', exp, -252), 254)
500 elif bits == 64:
501 exp = ('imin', ('imax', exp, -2044), 2046)
502 else:
503 assert False
504
505 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
506 # (We use ishr which isn't the same for -1, but the -1 case still works
507 # since we use exp-exp/2 as the second exponent.) While the spec
508 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
509 # work with denormals and doesn't allow for the full swing in exponents
510 # that you can get with normalized values. Instead, we create two powers
511 # of two and multiply by them each in turn. That way the effective range
512 # of our exponent is doubled.
513 pow2_1 = fexp2i(('ishr', exp, 1), bits)
514 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)), bits)
515 return ('fmul', ('fmul', f, pow2_1), pow2_2)
516
517 optimizations += [
518 (('ldexp@32', 'x', 'exp'), ldexp('x', 'exp', 32)),
519 (('ldexp@64', 'x', 'exp'), ldexp('x', 'exp', 64)),
520 ]
521
522 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
523 def bitfield_reverse(u):
524 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
525 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
526 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
527 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
528 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
529
530 return step5
531
532 optimizations += [(bitfield_reverse('x@32'), ('bitfield_reverse', 'x'))]
533
534 # For any float comparison operation, "cmp", if you have "a == a && a cmp b"
535 # then the "a == a" is redundant because it's equivalent to "a is not NaN"
536 # and, if a is a NaN then the second comparison will fail anyway.
537 for op in ['flt', 'fge', 'feq']:
538 optimizations += [
539 (('iand', ('feq', a, a), (op, a, b)), (op, a, b)),
540 (('iand', ('feq', a, a), (op, b, a)), (op, b, a)),
541 ]
542
543 # Add optimizations to handle the case where the result of a ternary is
544 # compared to a constant. This way we can take things like
545 #
546 # (a ? 0 : 1) > 0
547 #
548 # and turn it into
549 #
550 # a ? (0 > 0) : (1 > 0)
551 #
552 # which constant folding will eat for lunch. The resulting ternary will
553 # further get cleaned up by the boolean reductions above and we will be
554 # left with just the original variable "a".
555 for op in ['flt', 'fge', 'feq', 'fne',
556 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
557 optimizations += [
558 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
559 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
560 ((op, '#d', ('bcsel', a, '#b', '#c')),
561 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
562 ]
563
564 # This section contains "late" optimizations that should be run before
565 # creating ffmas and calling regular optimizations for the final time.
566 # Optimizations should go here if they help code generation and conflict
567 # with the regular optimizations.
568 before_ffma_optimizations = [
569 # Propagate constants down multiplication chains
570 (('~fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fmul', ('fmul', a, c), b)),
571 (('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('imul', ('imul', a, c), b)),
572 (('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fadd', ('fadd', a, c), b)),
573 (('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('iadd', ('iadd', a, c), b)),
574
575 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
576 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
577 (('~fadd', ('fneg', a), a), 0.0),
578 (('iadd', ('ineg', a), a), 0),
579 (('iadd', ('ineg', a), ('iadd', a, b)), b),
580 (('iadd', a, ('iadd', ('ineg', a), b)), b),
581 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
582 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
583 ]
584
585 # This section contains "late" optimizations that should be run after the
586 # regular optimizations have finished. Optimizations should go here if
587 # they help code generation but do not necessarily produce code that is
588 # more easily optimizable.
589 late_optimizations = [
590 # Most of these optimizations aren't quite safe when you get infinity or
591 # Nan involved but the first one should be fine.
592 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
593 (('flt', ('fneg', ('fadd', a, b)), 0.0), ('flt', ('fneg', a), b)),
594 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
595 (('~fge', ('fneg', ('fadd', a, b)), 0.0), ('fge', ('fneg', a), b)),
596 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
597 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
598
599 (('~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)))),
600
601 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
602 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
603 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
604 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
605
606 (('b2f(is_used_more_than_once)', ('inot', a)), ('bcsel', a, 0.0, 1.0)),
607 (('fneg(is_used_more_than_once)', ('b2f', ('inot', a))), ('bcsel', a, -0.0, -1.0)),
608
609 # we do these late so that we don't get in the way of creating ffmas
610 (('fmin', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmin', a, b))),
611 (('fmax', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmax', a, b))),
612 ]
613
614 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
615 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_before_ffma",
616 before_ffma_optimizations).render()
617 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
618 late_optimizations).render()