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Fix deep shift pattern performance (#6379) (#6420)

This commit is contained in:
Geza Lore 2025-09-11 16:10:14 +01:00 committed by GitHub
parent 56927fb955
commit 4866cfa09f
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GPG Key ID: B5690EEEBB952194
3 changed files with 214 additions and 2 deletions
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18
src/V3Const.cpp
View File

@ -1290,7 +1290,20 @@ class ConstVisitor final : public VNVisitor {
if (nodep->width() != lhsp->width()) return false;
if (nodep->width() != lhsp->lhsp()->width()) return false;
if (nodep->width() != lhsp->rhsp()->width()) return false;
return true;
// Only do it if we can fruther reduce one of the sides if pulling the shift through:
// - Either operands are constants
if (VN_IS(lhsp->lhsp(), Const)) return true;
if (VN_IS(lhsp->rhsp(), Const)) return true;
// - Const shift on either side
if (AstNodeBiop* const llp = VN_CAST(lhsp->lhsp(), NodeBiop)) {
return (VN_IS(llp, ShiftL) || VN_IS(llp, ShiftR)) && VN_IS(llp->rhsp(), Const);
}
if (AstNodeBiop* const lrp = VN_CAST(lhsp->rhsp(), NodeBiop)) {
return (VN_IS(lrp, ShiftL) || VN_IS(lrp, ShiftR)) && VN_IS(lrp->rhsp(), Const);
}
// Otherwise we would increase logic size
return false;
}
bool operandShiftShift(const AstNodeBiop* nodep) {
// We could add a AND though.
@ -1917,7 +1930,8 @@ class ConstVisitor final : public VNVisitor {
VL_DO_DANGLING(pushDeletep(nodep), nodep);
}
void replaceShiftOp(AstNodeBiop* nodep) {
UINFO(5, "SHIFT(AND(a,b),CONST)->AND(SHIFT(a,CONST),SHIFT(b,CONST)) " << nodep);
UINFO(5, "SHIFT(AND(a,b),CONST) with a/b special ->AND(SHIFT(a,CONST),SHIFT(b,CONST)) "
<< nodep);
const int width = nodep->width();
const int widthMin = nodep->widthMin();
VNRelinker handle;

18
test_regress/t/t_opt_const_big_or_tree.py Executable file
View File

@ -0,0 +1,18 @@
#!/usr/bin/env python3
# DESCRIPTION: Verilator: Verilog Test driver/expect definition
#
# Copyright 2025 by Wilson Snyder. This program is free software; you
# can redistribute it and/or modify it under the terms of either the GNU
# Lesser General Public License Version 3 or the Perl Artistic License
# Version 2.0.
# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
import vltest_bootstrap
test.scenarios('vlt_all')
test.timeout(10)
test.compile(verilator_make_gmake=False)
test.passes()

180
test_regress/t/t_opt_const_big_or_tree.v Normal file
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@ -0,0 +1,180 @@
// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2025 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0
module t (input x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13,
x14, x15, x16, x17, x18, x19, x20, x21, x22, x23, x24, x25, x26, x27, x28,
x29, x30, x31, x32, x33, x34, x35, x36, x37, x38, x39, x40, x41, x42, x43,
x44, x45, x46, x47, x48, x49, x50, x51, x52, x53, x54, x55, x56, x57, x58,
x59, x60, x61, x62, x63, x64, x65, x66, x67, x68, x69, x70, x71, x72, x73,
x74, x75, x76, x77, x78, x79, x80, x81, x82, x83, x84, x85, x86, x87, x88,
x89, x90, x91, x92, x93, x94, x95, x96, x97, x98, x99, x100, x101, x102,
x103, x104, x105, x106, x107, x108, x109, x110, x111, x112, x113, x114, x115,
x116, x117, x118, x119, x120, x121, x122, x123, x124, x125, x126, x127, x128,
x129, x130, x131, x132, x133, x134, x135, x136, x137, x138, x139, x140, x141,
x142, x143, x144, x145, x146, x147, x148, x149, x150, x151, x152, x153, x154,
x155, x156, x157, x158, x159, x160, x161, x162, x163, x164, x165, x166, x167,
x168, x169, x170, x171, x172, x173, x174, x175, x176, x177, x178, x179, x180,
x181, x182, x183, x184, x185, x186, x187, x188, x189, x190, x191, x192, x193,
x194, x195, x196, x197, x198, x199, x200, x201, x202, x203, x204, x205, x206,
x207, x208, x209, x210, x211, x212, x213, x214, x215, x216, x217, x218, x219,
x220, x221, x222, x223, x224, x225, x226, x227, x228, x229, x230, x231, x232,
x233, x234, x235, x236, x237, x238, x239, x240, x241, x242, x243, x244, x245,
x246, x247, x248, x249, x250, x251, x252, x253, x254, x255, x256, x257, x258,
x259, x260, x261, x262, x263, x264, x265, x266, x267, x268, x269, x270, x271,
x272, x273, x274, x275, x276, x277, x278, x279, x280, x281, x282, x283, x284,
x285, x286, x287, x288, x289, x290, x291, x292, x293, x294, x295, x296, x297,
x298, x299, x300, x301, x302, x303, x304, x305, x306, x307, x308, x309, x310,
x311, x312, x313, x314, x315, x316, x317, x318, x319, x320, x321, x322, x323,
x324, x325, x326, x327, x328, x329, x330, x331, x332, x333, x334, x335, x336,
x337, x338, x339, x340, x341, x342, x343, x344, x345, x346, x347, x348, x349,
x350, x351, x352, x353, x354, x355, x356, x357, x358, x359, x360, x361, x362,
x363, x364, x365, x366, x367, x368, x369, x370, x371, x372, x373, x374, x375,
x376, x377, x378, x379, x380, x381, x382, x383, x384, x385, x386, x387, x388,
x389, x390, x391, x392, x393, x394, x395, x396, x397, x398, x399, x400, x401,
x402, x403, x404, x405, x406, x407, x408, x409, x410, x411, x412, x413, x414,
x415, x416, x417, x418, x419, x420, x421, x422, x423, x424, x425, x426, x427,
x428, x429, x430, x431, x432, x433, x434, x435, x436, x437, x438, x439, x440,
x441, x442, x443, x444, x445, x446, x447, x448, x449, x450, x451, x452, x453,
x454, x455, x456, x457, x458, x459, x460, x461, x462, x463, x464, x465, x466,
x467, x468, x469, x470, x471, x472, x473, x474, x475, x476, x477, x478, x479,
x480, x481, x482, x483, x484, x485, x486, x487, x488, x489, x490, x491, x492,
x493, x494, x495, x496, x497, x498, x499, x500, x501, x502, x503, x504, x505,
x506, x507, x508, x509, x510, x511, x512, x513, x514, x515, x516, x517, x518,
x519, x520, x521, x522, x523, x524, x525, x526, x527, x528, x529, x530, x531,
x532, x533, x534, x535, x536, x537, x538, x539, x540, x541, x542, x543, x544,
x545, x546, x547, x548, x549, x550, x551, x552, x553, x554, x555, x556, x557,
x558, x559, x560, x561, x562, x563, x564, x565, x566, x567, x568, x569, x570,
x571, x572, x573, x574, x575, x576, x577, x578, x579, x580, x581, x582, x583,
x584, x585, x586, x587, x588, x589, x590, x591, x592, x593, x594, x595, x596,
x597, x598, x599, x600, x601, x602, x603, x604, x605, x606, x607, x608, x609,
x610, x611, x612, x613, x614, x615, x616, x617, x618, x619, x620, x621, x622,
x623, x624, x625, x626, x627, x628, x629, x630, x631, x632, x633, x634, x635,
x636, x637, x638, x639, x640, x641, x642, x643, x644, x645, x646, x647, x648,
x649, x650, x651, x652, x653, x654, x655, x656, x657, x658, x659, x660, x661,
x662, x663, x664, x665, x666, x667, x668, x669, x670, x671, x672, x673, x674,
x675, x676, x677, x678, x679, x680, x681, x682, x683, x684, x685, x686, x687,
x688, x689, x690, x691, x692, x693, x694, x695, x696, x697, x698, x699, x700,
x701, x702, x703, x704, x705, x706, x707, x708, x709, x710, x711, x712, x713,
x714, x715, x716, x717, x718, x719, x720, x721, x722, x723, x724, x725, x726,
x727, x728, x729, x730, x731, x732, x733, x734, x735, x736, x737, x738, x739,
x740, x741, x742, x743, x744, x745, x746, x747, x748, x749, x750, x751, x752,
x753, x754, x755, x756, x757, x758, x759, x760, x761, x762, x763, x764, x765,
x766, x767, x768, x769, x770, x771, x772, x773, x774, x775, x776, x777, x778,
x779, x780, x781, x782, x783, x784, x785, x786, x787, x788, x789, x790, x791,
x792, x793, x794, x795, x796, x797, x798, x799, x800, x801, x802, x803, x804,
x805, x806, x807, x808, x809, x810, x811, x812, x813, x814, x815, x816, x817,
x818, x819, x820, x821, x822, x823, x824, x825, x826, x827, x828, x829, x830,
x831, x832, x833, x834, x835, x836, x837, x838, x839, x840, x841, x842, x843,
x844, x845, x846, x847, x848, x849, x850, x851, x852, x853, x854, x855, x856,
x857, x858, x859, x860, x861, x862, x863, x864, x865, x866, x867, x868, x869,
x870, x871, x872, x873, x874, x875, x876, x877, x878, x879, x880, x881, x882,
x883, x884, x885, x886, x887, x888, x889, x890, x891, x892, x893, x894, x895,
x896, x897, x898, x899, x900, x901, x902, x903, x904, x905, x906, x907, x908,
x909, x910, x911, x912, x913, x914, x915, x916, x917, x918, x919, x920, x921,
x922, x923, x924, x925, x926, x927, x928, x929, x930, x931, x932, x933, x934,
x935, x936, x937, x938, x939, x940, x941, x942, x943, x944, x945, x946, x947,
x948, x949, x950, x951, x952, x953, x954, x955, x956, x957, x958, x959, x960,
x961, x962, x963, x964, x965, x966, x967, x968, x969, x970, x971, x972, x973,
x974, x975, x976, x977, x978, x979, x980, x981, x982, x983, x984, x985, x986,
x987, x988, x989, x990, x991, x992, x993, x994, x995, x996, x997, x998, x999,
output [1:0] out
);
assign out = {(x0 | x1 | x2 | x3 | x4 | x5 | x6 | x7 | x8 | x9 | x10 | x11
| x12 | x13 | x14 | x15 | x16 | x17 | x18 | x19 | x20 | x21 | x22 | x23
| x24 | x25 | x26 | x27 | x28 | x29 | x30 | x31 | x32 | x33 | x34 | x35
| x36 | x37 | x38 | x39 | x40 | x41 | x42 | x43 | x44 | x45 | x46 | x47
| x48 | x49 | x50 | x51 | x52 | x53 | x54 | x55 | x56 | x57 | x58 | x59
| x60 | x61 | x62 | x63 | x64 | x65 | x66 | x67 | x68 | x69 | x70 | x71
| x72 | x73 | x74 | x75 | x76 | x77 | x78 | x79 | x80 | x81 | x82 | x83
| x84 | x85 | x86 | x87 | x88 | x89 | x90 | x91 | x92 | x93 | x94 | x95
| x96 | x97 | x98 | x99 | x100 | x101 | x102 | x103 | x104 | x105 | x106
| x107 | x108 | x109 | x110 | x111 | x112 | x113 | x114 | x115 | x116 | x117
| x118 | x119 | x120 | x121 | x122 | x123 | x124 | x125 | x126 | x127 | x128
| x129 | x130 | x131 | x132 | x133 | x134 | x135 | x136 | x137 | x138 | x139
| x140 | x141 | x142 | x143 | x144 | x145 | x146 | x147 | x148 | x149 | x150
| x151 | x152 | x153 | x154 | x155 | x156 | x157 | x158 | x159 | x160 | x161
| x162 | x163 | x164 | x165 | x166 | x167 | x168 | x169 | x170 | x171 | x172
| x173 | x174 | x175 | x176 | x177 | x178 | x179 | x180 | x181 | x182 | x183
| x184 | x185 | x186 | x187 | x188 | x189 | x190 | x191 | x192 | x193 | x194
| x195 | x196 | x197 | x198 | x199 | x200 | x201 | x202 | x203 | x204 | x205
| x206 | x207 | x208 | x209 | x210 | x211 | x212 | x213 | x214 | x215 | x216
| x217 | x218 | x219 | x220 | x221 | x222 | x223 | x224 | x225 | x226 | x227
| x228 | x229 | x230 | x231 | x232 | x233 | x234 | x235 | x236 | x237 | x238
| x239 | x240 | x241 | x242 | x243 | x244 | x245 | x246 | x247 | x248 | x249
| x250 | x251 | x252 | x253 | x254 | x255 | x256 | x257 | x258 | x259 | x260
| x261 | x262 | x263 | x264 | x265 | x266 | x267 | x268 | x269 | x270 | x271
| x272 | x273 | x274 | x275 | x276 | x277 | x278 | x279 | x280 | x281 | x282
| x283 | x284 | x285 | x286 | x287 | x288 | x289 | x290 | x291 | x292 | x293
| x294 | x295 | x296 | x297 | x298 | x299 | x300 | x301 | x302 | x303 | x304
| x305 | x306 | x307 | x308 | x309 | x310 | x311 | x312 | x313 | x314 | x315
| x316 | x317 | x318 | x319 | x320 | x321 | x322 | x323 | x324 | x325 | x326
| x327 | x328 | x329 | x330 | x331 | x332 | x333 | x334 | x335 | x336 | x337
| x338 | x339 | x340 | x341 | x342 | x343 | x344 | x345 | x346 | x347 | x348
| x349 | x350 | x351 | x352 | x353 | x354 | x355 | x356 | x357 | x358 | x359
| x360 | x361 | x362 | x363 | x364 | x365 | x366 | x367 | x368 | x369 | x370
| x371 | x372 | x373 | x374 | x375 | x376 | x377 | x378 | x379 | x380 | x381
| x382 | x383 | x384 | x385 | x386 | x387 | x388 | x389 | x390 | x391 | x392
| x393 | x394 | x395 | x396 | x397 | x398 | x399 | x400 | x401 | x402 | x403
| x404 | x405 | x406 | x407 | x408 | x409 | x410 | x411 | x412 | x413 | x414
| x415 | x416 | x417 | x418 | x419 | x420 | x421 | x422 | x423 | x424 | x425
| x426 | x427 | x428 | x429 | x430 | x431 | x432 | x433 | x434 | x435 | x436
| x437 | x438 | x439 | x440 | x441 | x442 | x443 | x444 | x445 | x446 | x447
| x448 | x449 | x450 | x451 | x452 | x453 | x454 | x455 | x456 | x457 | x458
| x459 | x460 | x461 | x462 | x463 | x464 | x465 | x466 | x467 | x468 | x469
| x470 | x471 | x472 | x473 | x474 | x475 | x476 | x477 | x478 | x479 | x480
| x481 | x482 | x483 | x484 | x485 | x486 | x487 | x488 | x489 | x490 | x491
| x492 | x493 | x494 | x495 | x496 | x497 | x498 | x499 | x500 | x501 | x502
| x503 | x504 | x505 | x506 | x507 | x508 | x509 | x510 | x511 | x512 | x513
| x514 | x515 | x516 | x517 | x518 | x519 | x520 | x521 | x522 | x523 | x524
| x525 | x526 | x527 | x528 | x529 | x530 | x531 | x532 | x533 | x534 | x535
| x536 | x537 | x538 | x539 | x540 | x541 | x542 | x543 | x544 | x545 | x546
| x547 | x548 | x549 | x550 | x551 | x552 | x553 | x554 | x555 | x556 | x557
| x558 | x559 | x560 | x561 | x562 | x563 | x564 | x565 | x566 | x567 | x568
| x569 | x570 | x571 | x572 | x573 | x574 | x575 | x576 | x577 | x578 | x579
| x580 | x581 | x582 | x583 | x584 | x585 | x586 | x587 | x588 | x589 | x590
| x591 | x592 | x593 | x594 | x595 | x596 | x597 | x598 | x599 | x600 | x601
| x602 | x603 | x604 | x605 | x606 | x607 | x608 | x609 | x610 | x611 | x612
| x613 | x614 | x615 | x616 | x617 | x618 | x619 | x620 | x621 | x622 | x623
| x624 | x625 | x626 | x627 | x628 | x629 | x630 | x631 | x632 | x633 | x634
| x635 | x636 | x637 | x638 | x639 | x640 | x641 | x642 | x643 | x644 | x645
| x646 | x647 | x648 | x649 | x650 | x651 | x652 | x653 | x654 | x655 | x656
| x657 | x658 | x659 | x660 | x661 | x662 | x663 | x664 | x665 | x666 | x667
| x668 | x669 | x670 | x671 | x672 | x673 | x674 | x675 | x676 | x677 | x678
| x679 | x680 | x681 | x682 | x683 | x684 | x685 | x686 | x687 | x688 | x689
| x690 | x691 | x692 | x693 | x694 | x695 | x696 | x697 | x698 | x699 | x700
| x701 | x702 | x703 | x704 | x705 | x706 | x707 | x708 | x709 | x710 | x711
| x712 | x713 | x714 | x715 | x716 | x717 | x718 | x719 | x720 | x721 | x722
| x723 | x724 | x725 | x726 | x727 | x728 | x729 | x730 | x731 | x732 | x733
| x734 | x735 | x736 | x737 | x738 | x739 | x740 | x741 | x742 | x743 | x744
| x745 | x746 | x747 | x748 | x749 | x750 | x751 | x752 | x753 | x754 | x755
| x756 | x757 | x758 | x759 | x760 | x761 | x762 | x763 | x764 | x765 | x766
| x767 | x768 | x769 | x770 | x771 | x772 | x773 | x774 | x775 | x776 | x777
| x778 | x779 | x780 | x781 | x782 | x783 | x784 | x785 | x786 | x787 | x788
| x789 | x790 | x791 | x792 | x793 | x794 | x795 | x796 | x797 | x798 | x799
| x800 | x801 | x802 | x803 | x804 | x805 | x806 | x807 | x808 | x809 | x810
| x811 | x812 | x813 | x814 | x815 | x816 | x817 | x818 | x819 | x820 | x821
| x822 | x823 | x824 | x825 | x826 | x827 | x828 | x829 | x830 | x831 | x832
| x833 | x834 | x835 | x836 | x837 | x838 | x839 | x840 | x841 | x842 | x843
| x844 | x845 | x846 | x847 | x848 | x849 | x850 | x851 | x852 | x853 | x854
| x855 | x856 | x857 | x858 | x859 | x860 | x861 | x862 | x863 | x864 | x865
| x866 | x867 | x868 | x869 | x870 | x871 | x872 | x873 | x874 | x875 | x876
| x877 | x878 | x879 | x880 | x881 | x882 | x883 | x884 | x885 | x886 | x887
| x888 | x889 | x890 | x891 | x892 | x893 | x894 | x895 | x896 | x897 | x898
| x899 | x900 | x901 | x902 | x903 | x904 | x905 | x906 | x907 | x908 | x909
| x910 | x911 | x912 | x913 | x914 | x915 | x916 | x917 | x918 | x919 | x920
| x921 | x922 | x923 | x924 | x925 | x926 | x927 | x928 | x929 | x930 | x931
| x932 | x933 | x934 | x935 | x936 | x937 | x938 | x939 | x940 | x941 | x942
| x943 | x944 | x945 | x946 | x947 | x948 | x949 | x950 | x951 | x952 | x953
| x954 | x955 | x956 | x957 | x958 | x959 | x960 | x961 | x962 | x963 | x964
| x965 | x966 | x967 | x968 | x969 | x970 | x971 | x972 | x973 | x974 | x975
| x976 | x977 | x978 | x979 | x980 | x981 | x982 | x983 | x984 | x985 | x986
| x987 | x988 | x989 | x990 | x991 | x992 | x993 | x994 | x995 | x996 | x997
| x998 | x999), 1'b0};
endmodule