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eda-tools/b2/relop.c
Werner Almesberger 9cafe23fb8 b2/: simplified and corrected logic behind relop_redundant
We now generate the operator map algorithmically, which is a bit less
classy than solving the logical equations, but easier to get right.

Also renamed the somewhat vague "redundant" to "unreachable".
2012-06-01 14:52:12 -03:00

86 lines
1.5 KiB
C

/*
* relop.c - Relational operators
*
* Copyright 2012 by Werner Almesberger
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <stdlib.h>
#include <stdio.h>
#include "relop.h"
/*
* Operator to use for
*
* (A op B) -> forall X: !(X opa A) -> !(X opb B))
*
* This is for unlimited sets of values. For limited sets of values, we could
* decide also in some edge cases, but let's save such sophistication for
* later.
*/
static const enum relop unreachable_op[idx_n][idx_n] = {
#include "unreachable.inc"
};
static int relop2index(enum relop op)
{
switch (op) {
case rel_lt:
return idx_lt;
case rel_le:
return idx_le;
case rel_eq:
return idx_eq;
case rel_ge:
return idx_ge;
case rel_gt:
return idx_gt;
default:
abort();
}
}
int relop_unreachable(enum relop opa, enum relop opb,
const void *a, const void *b,
int (*cmp)(const void *a, enum relop op, const void *b, const void *user),
const void *user)
{
return cmp(a,
unreachable_op[relop2index(opa)][relop2index(opb)], b, user);
}
void dump_relop(FILE *file, enum relop op)
{
switch (op) {
case rel_lt:
fprintf(file, "<");
break;
case rel_le:
fprintf(file, "<=");
break;
case rel_eq:
fprintf(file, "=");
break;
case rel_ge:
fprintf(file, ">=");
break;
case rel_gt:
fprintf(file, ">");
break;
default:
abort();
}
}