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| 1 | #!/usr/bin/perl |
| 2 | # |
| 3 | # genredmap.pl - Redundacy detector map generator |
| 4 | # |
| 5 | # Copyright 2012 by Werner Almesberger |
| 6 | # |
| 7 | # This program is free software; you can redistribute it and/or modify |
| 8 | # it under the terms of the GNU General Public License as published by |
| 9 | # the Free Software Foundation; either version 2 of the License, or |
| 10 | # (at your option) any later version. |
| 11 | # |
| 12 | |
| 13 | # |
| 14 | # This script finds the relational operators op = f(opa, opb), for which |
| 15 | # the following is true: |
| 16 | # |
| 17 | # forall A, B: (A op B) -> forall X: !(X opa A) -> !(X opa B) |
| 18 | # |
| 19 | # In other words: if, with X a variable and A and B constants, we have a |
| 20 | # cascade of the form |
| 21 | # |
| 22 | # if (X opa A) ...; |
| 23 | # else if (X opa B) ...; |
| 24 | # |
| 25 | # and A op B is true, then the second branch will never be taken. |
| 26 | # |
| 27 | |
| 28 | %op = ( |
| 29 | "lt" => sub { $_[0] < $_[1] }, |
| 30 | "le" => sub { $_[0] <= $_[1] }, |
| 31 | "eq" => sub { $_[0] == $_[1] }, |
| 32 | "ge" => sub { $_[0] >= $_[1] }, |
| 33 | "gt" => sub { $_[0] > $_[1] }, |
| 34 | |
| 35 | ); |
| 36 | |
| 37 | @ops = ("lt", "le", "eq", "ge", "gt"); |
| 38 | |
| 39 | $always = 0; |
| 40 | |
| 41 | $a = 2; |
| 42 | @v = (0, 1, 2, 3, 4); |
| 43 | |
| 44 | for $opa (@ops) { |
| 45 | #next unless $opa eq "lt"; |
| 46 | for $opb (@ops) { |
| 47 | #next unless $opb eq "lt"; |
| 48 | $best = 0; |
| 49 | OP: for $op (@ops) { |
| 50 | $hit = 0; |
| 51 | for $b (@v) { |
| 52 | #print "($opa, $opb) $a $op $b\n"; |
| 53 | next unless $op{$op}->($a, $b); |
| 54 | for $x (@v) { |
| 55 | #print " A: $x $opa $a\n"; |
| 56 | next if $op{$opa}->($x, $a); |
| 57 | #print " B: $x $opb $b\n"; |
| 58 | next OP |
| 59 | if $op{$opb}->($x, $b) != $always; |
| 60 | $hit++; |
| 61 | #print " HIT ($hit)\n"; |
| 62 | } |
| 63 | } |
| 64 | if ($hit > $best) { |
| 65 | $best = $hit; |
| 66 | $best_op = $op; |
| 67 | } |
| 68 | } |
| 69 | print "\t[idx_$opa][idx_$opb] = rel_$best_op,\n" if $best; |
| 70 | } |
| 71 | } |
| 72 |
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