17-fyi-simplify-augment.patch

[Akim Demaille]

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * src/LR0.c (augment_automaton): Better variable locality.
        Remove an impossible branch: if there is a state corresponding to
        the start symbol being shifted, then there is shift for the start
        symbol from the initial state.
        
        
Index: src/LR0.c
--- src/LR0.c Sat, 08 Dec 2001 21:39:43 +0100 akim
+++ src/LR0.c Sat, 08 Dec 2001 22:02:25 +0100 akim
@@ -457,67 +457,55 @@
   else
     {
       state_t *statep = first_state->next;
-      shifts *sp = first_state->shifts;
-      shifts *sp1 = NULL;
       /* The states reached by shifts from FIRST_STATE are numbered
         1..(SP->NSHIFTS).  Look for one reached by START_SYMBOL.
         This is typical of `start: start ... ;': there is a state
         with the item `start: start . ...'.  We want to add a `shift
         on EOF to eof-shifting state here.  */
       while (statep->accessing_symbol != start_symbol
-            && statep->number < sp->nshifts)
+            && statep->number < first_state->shifts->nshifts)
        statep = statep->next;
 
       if (statep->accessing_symbol == start_symbol)
        {
-         /* We already have a next-to-final state, i.e., for `start:
+         /* We already have STATEP, a next-to-final state for `start:
             start . ...'.  Make sure it has a shift to what will be
             the final state.  */
-         while (sp && sp->number < statep->number)
+         int i;
+
+         /* Find the shift that leads to this STATEP. */
+         shifts *sp = first_state->shifts;
+         shifts *sp1 = NULL;
+         shifts *sp2 = NULL;
+         while (sp->number < statep->number)
            {
              sp1 = sp;
              sp = sp->next;
            }
 
-         if (sp && sp->number == statep->number)
-           {
-             int i;
-             shifts *sp2 = shifts_new (sp->nshifts + 1);
-             sp2->number = statep->number;
-             statep->shifts = sp2;
-             sp2->shifts[0] = nstates;
-             for (i = sp->nshifts; i > 0; i--)
-               sp2->shifts[i] = sp->shifts[i - 1];
+         sp2 = shifts_new (sp->nshifts + 1);
+         sp2->number = statep->number;
+         statep->shifts = sp2;
+         sp2->shifts[0] = nstates;
+         for (i = sp->nshifts; i > 0; i--)
+           sp2->shifts[i] = sp->shifts[i - 1];
 
-             /* Patch sp2 into the chain of shifts in place of sp,
-                following sp1.  */
-             sp2->next = sp->next;
-             sp1->next = sp2;
-             if (sp == last_shift)
-               last_shift = sp2;
-             XFREE (sp);
-           }
-         else
-           {
-             shifts *sp2 = shifts_new (1);
-             sp2->number = statep->number;
-             statep->shifts = sp2;
-             sp2->shifts[0] = nstates;
+         /* Patch sp2 into the chain of shifts in place of sp,
+            following sp1.  */
+         sp2->next = sp->next;
+         sp1->next = sp2;
+         if (sp == last_shift)
+           last_shift = sp2;
+         XFREE (sp);
 
-             /* Patch sp2 into the chain of shifts between sp1 and sp.  */
-             sp2->next = sp;
-             sp1->next = sp2;
-             if (sp == 0)
-               last_shift = sp2;
-           }
          insert_eof_shifting_state ();
        }
       else
        {
          /* There is no state for `start: start . ...'. */
          int i, k;
-         shifts *sp2;
-         sp = first_shift;
+         shifts *sp = first_state->shifts;
+         shifts *sp2 = NULL;
 
          /* There is no next-to-final state as yet.  */
          /* Add one more shift in first_shift,