Delete a superfluous and buggy optimization

From-SVN: r31670

gcc/ChangeLog

+2000-01-28  Bernd Schmidt  <bernds@cygnus.co.uk>
+
+	* jump.c (jump_optimize_1): Delete an optimization that is also done
+	by merge_blocks in flow.
+
 2000-01-28  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* diagnostic.c (build_message_string, output_printf,

gcc/jump.c

@@ -1995,125 +1995,6 @@ jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, mark_labels_only)
 #endif
 	  else
 	    {
-	      /* Look for   if (foo) bar; else break;  */
-	      /* The insns look like this:
-		 insn = condjump label1;
-		 ...range1 (some insns)...
-		 jump label2;
-		 label1:
-		 ...range2 (some insns)...
-		 jump somewhere unconditionally
-		 label2:  */
-	      {
-		rtx label1 = next_label (insn);
-		rtx range1end = label1 ? prev_active_insn (label1) : 0;
-		/* Don't do this optimization on the first round, so that
-		   jump-around-a-jump gets simplified before we ask here
-		   whether a jump is unconditional.
-
-		   Also don't do it when we are called after reload since
-		   it will confuse reorg.  */
-		if (! first
-		    && (reload_completed ? ! flag_delayed_branch : 1)
-		    /* Make sure INSN is something we can invert.  */
-		    && condjump_p (insn)
-		    && label1 != 0
-		    && JUMP_LABEL (insn) == label1
-		    && LABEL_NUSES (label1) == 1
-		    && GET_CODE (range1end) == JUMP_INSN
-		    && simplejump_p (range1end))
-		  {
-		    rtx label2 = next_label (label1);
-		    rtx range2end = label2 ? prev_active_insn (label2) : 0;
-		    if (range1end != range2end
-			&& JUMP_LABEL (range1end) == label2
-			&& GET_CODE (range2end) == JUMP_INSN
-			&& GET_CODE (NEXT_INSN (range2end)) == BARRIER
-			/* Invert the jump condition, so we
-			   still execute the same insns in each case.  */
-			&& invert_jump (insn, label1))
-		      {
-			rtx range1beg = next_active_insn (insn);
-			rtx range2beg = next_active_insn (label1);
-			rtx range1after, range2after;
-			rtx range1before, range2before;
-			rtx rangenext;
-
-			/* Include in each range any notes before it, to be
-			   sure that we get the line number note if any, even
-			   if there are other notes here.  */
-			while (PREV_INSN (range1beg)
-			       && GET_CODE (PREV_INSN (range1beg)) == NOTE)
-			  range1beg = PREV_INSN (range1beg);
-
-			while (PREV_INSN (range2beg)
-			       && GET_CODE (PREV_INSN (range2beg)) == NOTE)
-			  range2beg = PREV_INSN (range2beg);
-
-			/* Don't move NOTEs for blocks or loops; shift them
-			   outside the ranges, where they'll stay put.  */
-			range1beg = squeeze_notes (range1beg, range1end);
-			range2beg = squeeze_notes (range2beg, range2end);
-
-			/* Get current surrounds of the 2 ranges.  */
-			range1before = PREV_INSN (range1beg);
-			range2before = PREV_INSN (range2beg);
-			range1after = NEXT_INSN (range1end);
-			range2after = NEXT_INSN (range2end);
-
-			/* Splice range2 where range1 was.  */
-			NEXT_INSN (range1before) = range2beg;
-			PREV_INSN (range2beg) = range1before;
-			NEXT_INSN (range2end) = range1after;
-			PREV_INSN (range1after) = range2end;
-			/* Splice range1 where range2 was.  */
-			NEXT_INSN (range2before) = range1beg;
-			PREV_INSN (range1beg) = range2before;
-			NEXT_INSN (range1end) = range2after;
-			PREV_INSN (range2after) = range1end;
-
-			/* Check for loop notes between the end of
-			   range2, and the next code label.  If there is one,
-			   then what we have really seen is
-			   if (foo) break; end_of_loop;
-			   and moved the break sequence outside the loop.
-			   We must move LOOP_END, LOOP_VTOP and LOOP_CONT
-			   notes (in order) to where the loop really ends now,
-			   or we will confuse loop optimization.  Stop if we
-			   find a LOOP_BEG note first, since we don't want to
-			   move the notes in that case.  */
-			for (;range2after != label2; range2after = rangenext)
-			  {
-			    rangenext = NEXT_INSN (range2after);
-			    if (GET_CODE (range2after) == NOTE)
-			      {
-				int kind = NOTE_LINE_NUMBER (range2after);
-				if (kind == NOTE_INSN_LOOP_END
-				    || kind == NOTE_INSN_LOOP_VTOP
-				    || kind == NOTE_INSN_LOOP_CONT)
-				  {
-				    NEXT_INSN (PREV_INSN (range2after))
-				      = rangenext;
-				    PREV_INSN (rangenext)
-				      = PREV_INSN (range2after);
-				    PREV_INSN (range2after) 
-				      = PREV_INSN (range1beg);
-				    NEXT_INSN (range2after) = range1beg;
-				    NEXT_INSN (PREV_INSN (range1beg))
-				      = range2after;
-				    PREV_INSN (range1beg) = range2after;
-				  }
-				else if (NOTE_LINE_NUMBER (range2after)
-					 == NOTE_INSN_LOOP_BEG)
-				  break;
-			      }
-			  }
-			changed = 1;
-			continue;
-		      }
-		  }
-	      }
-
 	      /* Now that the jump has been tensioned,
 		 try cross jumping: check for identical code
 		 before the jump and before its target label.  */