[svn:parrot] r11880 - trunk/compilers/imcc

[leo]

Author: leo
Date: Sun Mar 12 10:21:37 2006
New Revision: 11880

Modified:
   trunk/compilers/imcc/optimizer.c

Log:
fix invalid mem access in constant_propagation

Modified: trunk/compilers/imcc/optimizer.c
==============================================================================
--- trunk/compilers/imcc/optimizer.c    (original)
+++ trunk/compilers/imcc/optimizer.c    Sun Mar 12 10:21:37 2006
@@ -478,7 +478,7 @@
 static int
 constant_propagation(Interp *interpreter, IMC_Unit * unit)
 {
-    Instruction *ins, *ins2, *tmp;
+    Instruction *ins, *ins2, *tmp, *prev;
     int op;
     int i;
     char fullname[128];
@@ -530,21 +530,28 @@
                                 unit, ins2->op, ins2->r, ins2->opsize,
                                 &found);
                             if (found) {
-                                subst_ins(unit, ins2, tmp, 1);
-                                any = 1;
-                                IMCC_debug(interpreter, DEBUG_OPT2," reduced 
to %I\n", tmp);
+                                prev = ins2->prev;
+                                if (prev) {
+                                    subst_ins(unit, ins2, tmp, 1);
+                                    any = 1;
+                                    IMCC_debug(interpreter, DEBUG_OPT2,
+                                            " reduced to %I\n", tmp);
+                                    ins2 = prev->next;
+                                }
                             } else {
                                 op = check_op(interpreter, fullname, ins2->op,
                                     ins2->r, ins2->n_r, ins2->keys);
                                 if (op < 0) {
                                     ins2->r[i] = old;
-                                    IMCC_debug(interpreter, DEBUG_OPT2," - no 
%s\n", fullname);
+                                    IMCC_debug(interpreter, DEBUG_OPT2,
+                                            " - no %s\n", fullname);
                                 }
                                 else {
                                     --old->use_count;
                                     ins2->opnum = op;
                                     any = 1;
-                                    IMCC_debug(interpreter, DEBUG_OPT2," -> 
%I\n", ins2);
+                                    IMCC_debug(interpreter, DEBUG_OPT2,
+                                            " -> %I\n", ins2);
                                 }
                             }
                         }