Commit Graph

112 Commits

Author SHA1 Message Date
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"
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
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
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 (remove opt_compare step)
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