bug fix in constant set computations

diff --git a/lang/m2/comp/chk_expr.c b/lang/m2/comp/chk_expr.c
index 9693d1e..500b987 100644 (file)
--- a/lang/m2/comp/chk_expr.c
+++ b/lang/m2/comp/chk_expr.c
@@ -399,14 +399,8 @@ ChkSet(expp)
        nd = expp->nd_right;
 
        /* Now check the elements given, and try to compute a constant set.
-          First allocate room for the set, but only if it is'nt empty.
+          First allocate room for the set.
        */
-       if (! nd) {
-               /* The resulting set IS empty, so we just return
-               */
-               expp->nd_set = 0;
-               return 1;
-       }
        size = tp->tp_size * (sizeof(arith) / word_size);
        expp->nd_set = (arith *) Malloc(size);
        clear((char *) (expp->nd_set) , size);

diff --git a/lang/m2/comp/cstoper.c b/lang/m2/comp/cstoper.c
index 6785c3c..97b2b36 100644 (file)
--- a/lang/m2/comp/cstoper.c
+++ b/lang/m2/comp/cstoper.c
@@ -259,10 +259,9 @@ cstset(expp)
 
                i = expp->nd_left->nd_INT;
                expp->nd_class = Value;
-               expp->nd_INT = (i >= 0 && set2 != 0 &&
-                   i < setsize * wrd_bits &&
+               expp->nd_INT = (i >= 0 && i < setsize * wrd_bits &&
                    (set2[i / wrd_bits] & (1 << (i % wrd_bits))));
-               if (set2) free((char *) set2);
+               free((char *) set2);
        }
        else {
                set1 = expp->nd_left->nd_set;
@@ -272,12 +271,7 @@ cstset(expp)
                case '+':
                        /* Set union
                        */
-                       if (!set1) {
-                               resultset = set2;
-                               expp->nd_right->nd_set = 0;
-                               break;
-                       }
-                       if (set2) for (j = 0; j < setsize; j++) {
+                       for (j = 0; j < setsize; j++) {
                                *set1++ |= *set2++;
                        }
                        break;
@@ -285,14 +279,6 @@ cstset(expp)
                case '-':
                        /* Set difference
                        */
-                       if (!set1 || !set2) {
-                               /* The set from which something is substracted
-                                  is already empty, or the set that is
-                                  substracted is empty. In either case, the
-                                  result set is set1.
-                               */
-                               break;
-                       }
                        for (j = 0; j < setsize; j++) {
                                *set1++ &= ~*set2++;
                        }
@@ -301,19 +287,6 @@ cstset(expp)
                case '*':
                        /* Set intersection
                        */
-                       if (!set1) {
-                               /* set1 is empty, and so is the result set
-                               */
-                               break;
-                       }
-                       if (!set2) {
-                               /* set 2 is empty, so the result set must be
-                                  empty too.
-                               */
-                               resultset = set2;
-                               expp->nd_right->nd_set = 0;
-                               break;
-                       }
                        for (j = 0; j < setsize; j++) {
                                *set1++ &= *set2++;
                        }
@@ -322,15 +295,8 @@ cstset(expp)
                case '/':
                        /* Symmetric set difference
                        */
-                       if (!set1) {
-                               resultset = set2;
-                               expp->nd_right->nd_set = 0;
-                               break;
-                       }
-                       if (set2) {
-                               for (j = 0; j < setsize; j++) {
-                                       *set1++ ^= *set2++;
-                               }
+                       for (j = 0; j < setsize; j++) {
+                               *set1++ ^= *set2++;
                        }
                        break;
 
@@ -344,34 +310,26 @@ cstset(expp)
                        for (j = 0; j < setsize; j++) {
                                switch(expp->nd_symb) {
                                case GREATEREQUAL:
-                                       if (!set2) {j = setsize; break; }
-                                       if (!set1) break;
                                        if ((*set1 | *set2++) != *set1) break;
                                        set1++;
                                        continue;
                                case LESSEQUAL:
-                                       if (!set1) {j = setsize; break; }
-                                       if (!set2) break;
                                        if ((*set2 | *set1++) != *set2) break;
                                        set2++;
                                        continue;
                                case '=':
                                case '#':
-                                       if (!set1 && !set2) {
-                                               j = setsize; break;
-                                       }
-                                       if (!set1 || !set2) break;
                                        if (*set1++ != *set2++) break;
                                        continue;
                                }
-                               if (j < setsize) {
-                                       expp->nd_INT = expp->nd_symb == '#';
-                               }
-                               else {
-                                       expp->nd_INT = expp->nd_symb != '#';
-                               }
                                break;
                        }
+                       if (j < setsize) {
+                               expp->nd_INT = expp->nd_symb == '#';
+                       }
+                       else {
+                               expp->nd_INT = expp->nd_symb != '#';
+                       }
                        expp->nd_class = Value;
                        expp->nd_symb = INTEGER;
                        if (expp->nd_left->nd_set) {