re PR bootstrap/59279 (r205337 breaks bootstrap with java)

	PR bootstrap/59279
	Revert previous commit.

From-SVN: r205338

1 files changed, 32 insertions, 57 deletions

diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index e909b03..234e5b6 100644
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -2944,65 +2944,40 @@ delete_unreachable_blocks (void)
   return changed;
 }
 
-
-/* Look for, and delete, any dead jumptables between START and END.  */
-
-static void
-delete_dead_jump_tables_between (rtx start, rtx end)
-{
-  rtx insn, next;
-
-  for (insn = start; insn != end; insn = next)
-    {
-      next = NEXT_INSN (insn);
-      if (next != NULL_RTX
-	  && LABEL_P (insn)
-	  && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
-	  && JUMP_TABLE_DATA_P (next))
-	{
-	  rtx label = insn, jump = next;
-
-	  if (dump_file)
-	    fprintf (dump_file, "Dead jumptable %i removed\n",
-		     INSN_UID (insn));
-
-	  next = NEXT_INSN (next);
-	  delete_insn (jump);
-	  delete_insn (label);
-	}
-    }
-}
-
-
 /* Delete any jump tables never referenced.  We can't delete them at the
-   time of removing tablejump insn as the label preceding the jump table
-   data may be referenced by the preceding insns computing the destination.
-   So we delay deleting and garbage-collect them from time to time, after
-   a CFG cleanup.  */
-
+   time of removing tablejump insn as they are referenced by the preceding
+   insns computing the destination, so we delay deleting and garbagecollect
+   them once life information is computed.  */
 void
 delete_dead_jumptables (void)
 {
   basic_block bb;
 
-  /* Label reference count must up-to-date to detect dead jump tables.  */
-  rebuild_jump_labels (get_insns ());
-
+  /* A dead jump table does not belong to any basic block.  Scan insns
+     between two adjacent basic blocks.  */
   FOR_EACH_BB (bb)
     {
-      if (current_ir_type () == IR_RTL_CFGLAYOUT)
-	{
-	  /* Jump tables only appear in the header or footer of BB.  */
-	  delete_dead_jump_tables_between (BB_HEADER (bb), NULL_RTX);
-	  delete_dead_jump_tables_between (BB_FOOTER (bb), NULL_RTX);
-	}
-      else
+      rtx insn, next;
+
+      for (insn = NEXT_INSN (BB_END (bb));
+	   insn && !NOTE_INSN_BASIC_BLOCK_P (insn);
+	   insn = next)
 	{
-	  /* Jump tables are in the insns chain between basic blocks.  */
-	  rtx start = NEXT_INSN (BB_END (bb));
-	  rtx end = (bb->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
-	    ? NULL_RTX : BB_HEAD (bb->next_bb);
-	  delete_dead_jump_tables_between (start, end);
+	  next = NEXT_INSN (insn);
+	  if (LABEL_P (insn)
+	      && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
+	      && JUMP_TABLE_DATA_P (next))
+	    {
+	      rtx label = insn, jump = next;
+
+	      if (dump_file)
+		fprintf (dump_file, "Dead jumptable %i removed\n",
+			 INSN_UID (insn));
+
+	      next = NEXT_INSN (next);
+	      delete_insn (jump);
+	      delete_insn (label);
+	    }
 	}
     }
 }
@@ -3074,13 +3049,13 @@ cleanup_cfg (int mode)
   if (mode & CLEANUP_CROSSJUMP)
     remove_fake_exit_edges ();
 
-  /* Don't always call delete_dead_jumptables in cfglayout mode, because
-     jump tables can only appear in the headers and footers of basic blocks
-     and we usually are not interested in anything hiding there.
-     But if an expensive cleanup is called for, garbage-collect the dead
-     jump tables to get label reference counts right.  This sometimes
-     allows some labels to be removed and more basic blocks to be merged.  */
-  if (!(mode & CLEANUP_CFGLAYOUT) || (mode & CLEANUP_EXPENSIVE))
+  /* Don't call delete_dead_jumptables in cfglayout mode, because
+     that function assumes that jump tables are in the insns stream.
+     But we also don't _have_ to delete dead jumptables in cfglayout
+     mode because we shouldn't even be looking at things that are
+     not in a basic block.  Dead jumptables are cleaned up when
+     going out of cfglayout mode.  */
+  if (!(mode & CLEANUP_CFGLAYOUT))
     delete_dead_jumptables ();
 
   /* ???  We probably do this way too often.  */