whitequark
9e9846a6ea
opt_expr: refactor simplification of signed X>=0 and X<0. NFCI.
2019-01-02 03:01:25 +00:00
whitequark
8e53d2e0bf
opt_expr: simplify any unsigned comparisons with all-0 and all-1.
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Before this commit, only unsigned comparisons with all-0 would be
simplified. This commit also makes the code handling such comparisons
to be more rigorous and not abort on unexpected input.
2019-01-02 02:45:49 +00:00
Clifford Wolf
643f858acf
Bugfix in opt_expr handling of a<0 and a>=0
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Signed-off-by: Clifford Wolf <clifford@clifford.at>
2018-12-06 07:29:21 +01:00
Henner Zeller
3aa4484a3c
Consistent use of 'override' for virtual methods in derived classes.
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o Not all derived methods were marked 'override', but it is a great
feature of C++11 that we should make use of.
o While at it: touched header files got a -*- c++ -*- for emacs to
provide support for that language.
o use YS_OVERRIDE for all override keywords (though we should probably
use the plain keyword going forward now that C++11 is established)
2018-07-20 23:51:06 -07:00
Clifford Wolf
587056447e
Add optimization of tristate buffer with constant control input
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Signed-off-by: Clifford Wolf <clifford@clifford.at>
2018-05-12 15:18:27 +02:00
Clifford Wolf
68c42f3a19
Don't track , ... contradictions through x/z-bits
2017-08-25 16:18:17 +02:00
Clifford Wolf
db6d78a186
Add removing of redundant pairs of bits in ==, ===, !=, and !== to opt_expr
2017-08-25 16:02:15 +02:00
Clifford Wolf
649bb9374f
Add "opt_expr -fine" feature to remove neutral bits from reduce and logic operators
2017-07-26 18:28:55 +02:00
Clifford Wolf
0a02cdb93b
Fix and_or_buffer optimization in opt_expr for signed operators
2017-07-01 16:05:26 +02:00
Larry Doolittle
2021ddecb3
Squelch trailing whitespace
2017-04-12 15:11:09 +02:00
Clifford Wolf
95dae6d416
Fixed some "used uninitialized" warnings in opt_expr
2017-02-11 10:50:48 +01:00
Clifford Wolf
a5bfeb9e07
Add optimization of (a && 1'b1) and (a || 1'b0)
2017-02-11 10:05:00 +01:00
C-Elegans
94b272077d
Fix issue #306 , "Bug in opt -full"
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Add check for whether the high bit in the constant expression is greater
than the width of the variable, and optimizes that to a constant 1 or
0
2017-02-10 10:38:02 -05:00
Clifford Wolf
ffbe8d41f3
Fix indenting and log messages in code merged from opt_compare_pr
2017-01-31 16:20:56 +01:00
C-Elegans
a94c3694d7
Refactor and generalize the comparision optimization
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Generalizes the optimization to:
a < C,
a >= C,
C > a,
C <= a
2017-01-30 17:52:16 -05:00
C-Elegans
2fa0fd4a37
Do not use b.as_int() in calculation of bit set
2017-01-21 12:58:26 -05:00
C-Elegans
84f9cd0025
Optimize compares to powers of 2
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Remove opt_compare and put comparison pass in opt_expr
assuming a [7:0] is unsigned
a >= (1<<x) becomes |a[7:x]
a < (1<<x) becomes !a[7:x]
Additionally:
a >= 0 becomes constant true,
a < 0 becomes constant false
delete opt_compare.cc
revert opt.cc to commit b7cfb7dbd
2017-01-16 13:45:50 -05:00
Clifford Wolf
11f7b8a2a1
Added opt_expr support for div/mod by power-of-two
2016-05-29 12:17:36 +02:00
Clifford Wolf
0bc95f1e04
Added "yosys -D" feature
2016-04-21 23:28:37 +02:00
Clifford Wolf
f38ca3e18f
Improvements in opt_expr
2016-04-21 14:23:04 +02:00
Clifford Wolf
e2f6d61c00
Typo fixes in opt_expr and opt_merge
2016-03-31 09:56:56 +02:00
Clifford Wolf
1d0f0d668a
Renamed opt_const to opt_expr
2016-03-31 08:46:56 +02:00
