Re: DELETE_INSN() fails to delete BARRIER in some case

[Hiroyuki Machida <machida at sm dot sony dot co dot jp>]

Hi, 

In my previous mail, attached patch is only for gcc-3.0 branch.
Here is a patch for gcc-3.1 branch.

From: Hiroyuki Machida <machida@sm.sony.co.jp>
Subject: DELETE_INSN() fails to delete BARRIER in some case
Date: Fri, 05 Apr 2002 13:01:10 +0900 (JST)

> 
> Hello, all
> 
> Atsushi Nemoto <nemoto@toshiba-tops.co.jp> reported the optimizer
> bug of gcc-2.95.3 for mips-linux in 
>     http://marc.theaimsgroup.com/?l=linux-mips&m=101788946915832&w=2
> 
> I tracked down the bug and found DELETE_INSN() failed to delete
> BARRIER in some case. I think this problem potentially occures in
> any target, even in gcc-3.x.
> 
> I attached a patch, bootstraped on gcc-2.95.3 for mipsel-linux.
> Please apply it to gcc-3.0, gcc-3.1 branch and HEAD.
> 
> Thanks.


Index: jump.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/jump.c,v
retrieving revision 1.205
diff -u -p -r1.205 jump.c
--- jump.c	21 Feb 2002 22:47:58 -0000	1.205
+++ jump.c	12 Apr 2002 05:30:38 -0000
@@ -1730,6 +1730,7 @@ delete_related_insns (insn)
   int was_code_label = (GET_CODE (insn) == CODE_LABEL);
   rtx note;
   rtx next = NEXT_INSN (insn), prev = PREV_INSN (insn);
+  rtx next_nonote = next_nonnote_insn(insn);
 
   while (next && INSN_DELETED_P (next))
     next = NEXT_INSN (next);
@@ -1740,11 +1741,18 @@ delete_related_insns (insn)
 
   delete_insn (insn);
 
-  /* If instruction is followed by a barrier,
-     delete the barrier too.  */
+  /* If instruction is followed by a barrier, delete the barrier too. 
+     In some case, there are multiple NOTEs like NOTE_INSN_BASIC_BLOCK 
+     but NOTE_INSN_DELETED, between INSN and BARRIER.
+     In another case, multiple BARRIERs follow INSN.*/
 
-  if (next != 0 && GET_CODE (next) == BARRIER)
-    delete_insn (next);
+  while (next_nonote != 0 && GET_CODE (next_nonote) == BARRIER)
+    {
+      rtx barrier = next_nonote;
+      next = NEXT_INSN (barrier);
+      next_nonote = next_nonnote_insn(barrier);
+      delete_barrier (barrier);
+    }
 
   /* If deleting a jump, decrement the count of the label,
      and delete the label if it is now unused.  */