rtl.h (insns_safe_to_move_p): New function.

* rtl.h (insns_safe_to_move_p): New function.
	* loop.c (find_and_verify_loops): Use it.
	* rtlanal.c (insns_safe_to_move_p): Define it.

From-SVN: r29509

gcc/ChangeLog

@@ -1,3 +1,9 @@
+Sun Sep 19 09:03:40 1999  Mark Mitchell  <mark@codesourcery.com>
+
+	* rtl.h (insns_safe_to_move_p): New function.
+	* loop.c (find_and_verify_loops): Use it.
+	* rtlanal.c (insns_safe_to_move_p): Define it.
+
 Sat Sep 18 16:01:18 1999  Alexandre Oliva  <oliva@lsd.ic.unicamp.br>
 
 	* config/i386/sol2.h (CPP_SPEC): Support -[p]threads

gcc/loop.c

@@ -2779,6 +2779,7 @@ find_and_verify_loops (f)
 	  {
 	    rtx p;
 	    rtx our_next = next_real_insn (insn);
+	    rtx last_insn_to_move = NEXT_INSN (insn);
 	    int dest_loop;
 	    int outer_loop = -1;
 
@@ -2830,7 +2831,11 @@ find_and_verify_loops (f)
 		&& INSN_UID (JUMP_LABEL (p)) != 0
 		&& condjump_p (p)
 		&& ! simplejump_p (p)
-		&& next_real_insn (JUMP_LABEL (p)) == our_next)
+		&& next_real_insn (JUMP_LABEL (p)) == our_next
+		/* If it's not safe to move the sequence, then we
+		   mustn't try.  */
+		&& insns_safe_to_move_p (p, NEXT_INSN (insn), 
+					 &last_insn_to_move))
 	      {
 		rtx target
 		  = JUMP_LABEL (insn) ? JUMP_LABEL (insn) : get_last_insn ();
@@ -2885,11 +2890,13 @@ find_and_verify_loops (f)
 
 		       /* Include the BARRIER after INSN and copy the
 			  block after LOC.  */
-		       new_label = squeeze_notes (new_label, NEXT_INSN (insn));
-		       reorder_insns (new_label, NEXT_INSN (insn), loc);
+		       new_label = squeeze_notes (new_label, 
+						  last_insn_to_move);
+		       reorder_insns (new_label, last_insn_to_move, loc);
 
 		       /* All those insns are now in TARGET_LOOP_NUM.  */
-		       for (q = new_label; q != NEXT_INSN (NEXT_INSN (insn));
+		       for (q = new_label; 
+			    q != NEXT_INSN (last_insn_to_move);
 			    q = NEXT_INSN (q))
 			 uid_loop_num[INSN_UID (q)] = target_loop_num;
 

gcc/rtl.h

@@ -1130,6 +1130,7 @@ extern int for_each_rtx                 PROTO((rtx *, rtx_function, void *));
 extern rtx regno_use_in			PROTO((int, rtx));
 extern int auto_inc_p			PROTO((rtx));
 extern void remove_node_from_expr_list	PROTO((rtx, rtx *));
+extern int insns_safe_to_move_p         PROTO((rtx, rtx, rtx *));
 
 /* flow.c */
 

gcc/rtlanal.c

@@ -2293,3 +2293,73 @@ auto_inc_p (x)
     }
   return 0;
 }
+
+/* Return 1 if the sequence of instructions beginning with FROM and up
+   to and including TO is safe to move.  If NEW_TO is non-NULL, and
+   the sequence is not already safe to move, but can be easily
+   extended to a sequence which is safe, then NEW_TO will point to the
+   end of the extended sequence.  */
+
+int
+insns_safe_to_move_p (from, to, new_to)
+     rtx from;
+     rtx to;
+     rtx *new_to;
+{
+  int eh_region_count = 0;
+  int past_to_p = 0;
+  rtx r = from;
+
+  while (r)
+    {
+      if (GET_CODE (r) == NOTE)
+	{
+	  switch (NOTE_LINE_NUMBER (r))
+	    {
+	    case NOTE_INSN_EH_REGION_BEG:
+	      ++eh_region_count;
+	      break;
+
+	    case NOTE_INSN_EH_REGION_END:
+	      if (eh_region_count == 0)
+		/* This sequence of instructions contains the end of
+		   an exception region, but not he beginning.  Moving
+		   it will cause chaos.  */
+		return 0;
+
+	      --eh_region_count;
+	      break;
+
+	    default:
+	      break;
+	    }
+	}
+      else if (past_to_p)
+	/* If we've passed TO, and we see a non-note instruction, we
+	   can't extend the sequence to a movable sequence.  */
+	return 0;
+
+      if (r == to)
+	{
+	  if (!new_to)
+	    /* It's OK to move the sequence if there were matched sets of
+	       exception region notes.  */
+	    return eh_region_count == 0;
+	  
+	  past_to_p = 1;
+	}
+
+      /* It's OK to move the sequence if there were matched sets of
+	 exception region notes.  */
+      if (past_to_p && eh_region_count == 0)
+	{
+	  *new_to = r;
+	  return 1;
+	}
+
+      /* Go to the next instruction.  */
+      r = NEXT_INSN (r);
+    }
+  
+  return 0;
+}

gcc/testsuite/g++.old-deja/g++.eh/crash1.C

@@ -0,0 +1,22 @@
+// Build don't link:
+// Special g++ Options: -O1 -fno-inline-functions
+
+struct A
+{
+  ~A ();
+};
+
+bool foo ();
+
+int i;
+int j;
+
+A bar ()
+{
+  for (i = 0; i < 1; ++i)
+    if (j)
+      {
+	A tmp;
+	return tmp;
+      }
+}