jump.c (squeeze_notes): Take parms by reference.

        * jump.c (squeeze_notes): Take parms by reference.  Handle END being
        a squeezable note.
        * rtl.h: Adjust.
        * ifcvt.c (dead_or_predicable): Adjust.
        * loop.c (find_and_verify_loops): Adjust.
        * stmt.c (expand_end_case): Adjust.
        * flow.c (merge_blocks_move_successor_nojumps): Adjust.  Modify the
        head and end insn pointers in the basic block, not just local copies.
        (merge_blocks_move_predecessor_nojumps): Likewise.

From-SVN: r45107

gcc/ChangeLog

+2001-08-22  Jason Merrill  <jason_merrill@redhat.com>
+
+	* jump.c (squeeze_notes): Take parms by reference.  Handle END being
+	a squeezable note.
+	* rtl.h: Adjust.
+	* ifcvt.c (dead_or_predicable): Adjust.
+	* loop.c (find_and_verify_loops): Adjust.
+	* stmt.c (expand_end_case): Adjust.
+	* flow.c (merge_blocks_move_successor_nojumps): Adjust.  Modify the
+	head and end insn pointers in the basic block, not just local copies.
+	(merge_blocks_move_predecessor_nojumps): Likewise.
+
 2001-08-22  Lars Brinkhoff  <lars@nocrew.org>
 
 	* Makefile.in, alias.c, basic-block.h, bb-reorder.c, bitmap.c,

gcc/flow.c

@@ -3074,13 +3074,10 @@ static int
 merge_blocks_move_predecessor_nojumps (a, b)
      basic_block a, b;
 {
-  rtx start, end, barrier;
+  rtx barrier;
   int index;
 
-  start = a->head;
-  end = a->end;
-
-  barrier = next_nonnote_insn (end);
+  barrier = next_nonnote_insn (a->end);
   if (GET_CODE (barrier) != BARRIER)
     abort ();
   flow_delete_insn (barrier);
@@ -3092,11 +3089,11 @@ merge_blocks_move_predecessor_nojumps (a, b)
      and adjust the block trees appropriately.   Even better would be to have
      a tighter connection between block trees and rtl so that this is not
      necessary.  */
-  start = squeeze_notes (start, end);
+  squeeze_notes (&a->head, &a->end);
 
   /* Scramble the insn chain.  */
-  if (end != PREV_INSN (b->head))
-    reorder_insns (start, end, PREV_INSN (b->head));
+  if (a->end != PREV_INSN (b->head))
+    reorder_insns (a->head, a->end, PREV_INSN (b->head));
 
   if (rtl_dump_file)
     {
@@ -3127,11 +3124,9 @@ static int
 merge_blocks_move_successor_nojumps (a, b)
      basic_block a, b;
 {
-  rtx start, end, barrier;
+  rtx barrier;
 
-  start = b->head;
-  end = b->end;
-  barrier = NEXT_INSN (end);
+  barrier = NEXT_INSN (b->end);
 
   /* Recognize a jump table following block B.  */
   if (barrier
@@ -3141,8 +3136,8 @@ merge_blocks_move_successor_nojumps (a, b)
       && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
 	  || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
     {
-      end = NEXT_INSN (barrier);
-      barrier = NEXT_INSN (end);
+      b->end = NEXT_INSN (barrier);
+      barrier = NEXT_INSN (b->end);
     }
 
   /* There had better have been a barrier there.  Delete it.  */
@@ -3156,10 +3151,10 @@ merge_blocks_move_successor_nojumps (a, b)
      and adjust the block trees appropriately.   Even better would be to have
      a tighter connection between block trees and rtl so that this is not
      necessary.  */
-  start = squeeze_notes (start, end);
+  squeeze_notes (&b->head, &b->end);
 
   /* Scramble the insn chain.  */
-  reorder_insns (start, end, a->end);
+  reorder_insns (b->head, b->end, a->end);
 
   /* Now blocks A and B are contiguous.  Merge them.  */
   merge_blocks_nomove (a, b);

gcc/ifcvt.c

@@ -2667,19 +2667,7 @@ dead_or_predicable (test_bb, merge_bb, other_bb, new_dest, reversep)
       if (end == merge_bb->end)
 	merge_bb->end = PREV_INSN (head);
 
-      head = squeeze_notes (head, end);
-      if (GET_CODE (end) == NOTE
-	  && (NOTE_LINE_NUMBER (end) == NOTE_INSN_BLOCK_END
-              || NOTE_LINE_NUMBER (end) == NOTE_INSN_BLOCK_BEG
-              || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_BEG
-              || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_END
-              || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_CONT
-              || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_VTOP))
-	{
-	  if (head == end)
-	    return TRUE;
-	  end = PREV_INSN (end);
-	}
+      squeeze_notes (&head, &end);
 
       reorder_insns (head, end, PREV_INSN (earliest));
     }

gcc/jump.c

@@ -539,19 +539,24 @@ duplicate_loop_exit_test (loop_start)
 }
 
 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
-   notes between START and END out before START.  Assume that END is not
-   such a note.  START may be such a note.  Returns the value of the new
-   starting insn, which may be different if the original start was such a
-   note.  */
+   notes between START and END out before START.  START and END may be such
+   notes.  Returns the values of the new starting and ending insns, which
+   may be different if the original ones were such notes.  */
 
-rtx
-squeeze_notes (start, end)
-     rtx start, end;
+void
+squeeze_notes (startp, endp)
+     rtx* startp;
+     rtx* endp;
 {
+  rtx start = *startp;
+  rtx end = *endp;
+
   rtx insn;
   rtx next;
+  rtx last = NULL;
+  rtx past_end = NEXT_INSN (end);
 
-  for (insn = start; insn != end; insn = next)
+  for (insn = start; insn != past_end; insn = next)
     {
       next = NEXT_INSN (insn);
       if (GET_CODE (insn) == NOTE
@@ -575,9 +580,19 @@ squeeze_notes (start, end)
 	      PREV_INSN (next) = prev;
 	    }
 	}
+      else
+	last = insn;
     }
 
-  return start;
+  /* There were no real instructions, and we can't represent an empty
+     range.  Die.  */
+  if (start == past_end)
+    abort ();
+
+  end = last;
+
+  *startp = start;
+  *endp = end;
 }
 
 /* Return the label before INSN, or put a new label there.  */

gcc/loop.c

@@ -2749,8 +2749,7 @@ find_and_verify_loops (f, loops)
 
 			/* Include the BARRIER after INSN and copy the
 			   block after LOC.  */
-			new_label = squeeze_notes (new_label,
-						   last_insn_to_move);
+			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.  */

gcc/rtl.h

@@ -1284,7 +1284,7 @@ extern void mark_jump_label		PARAMS ((rtx, rtx, int));
 extern void cleanup_barriers		PARAMS ((void));
 
 /* In jump.c */
-extern rtx squeeze_notes		PARAMS ((rtx, rtx));
+extern void squeeze_notes		PARAMS ((rtx *, rtx *));
 extern rtx delete_insn			PARAMS ((rtx));
 extern void delete_jump			PARAMS ((rtx));
 extern void delete_barrier		PARAMS ((rtx));

gcc/stmt.c

@@ -5152,7 +5152,7 @@ expand_end_case (orig_index)
   int ncases;
   rtx *labelvec;
   register int i;
-  rtx before_case;
+  rtx before_case, end;
   register struct nesting *thiscase = case_stack;
   tree index_expr, index_type;
   int unsignedp;
@@ -5414,8 +5414,10 @@ expand_end_case (orig_index)
 #endif
 	}
 
-      before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
-      reorder_insns (before_case, get_last_insn (),
+      before_case = NEXT_INSN (before_case);
+      end = get_last_insn ();
+      squeeze_notes (&before_case, &end);
+      reorder_insns (before_case, end,
 		     thiscase->data.case_stmt.start);
     }
   else