jump.c (reset_insn_reg_label_operand_notes): New function, split out from ...

	* jump.c (reset_insn_reg_label_operand_notes): New function,
	split out from ...
	(init_label_info): ... here.  Reset LABEL_NUSES in cfglayout mode.
	* cfgcleanup.c (delete_dead_jump_tables_between): New function,
	split out from ...
	(delete_dead_jumptables): ... here.  Handle cfglayout mode.
	(cleanup_cfg): Delete dead jump tables in cfglayout mode if an
	expensive CFG cleanup is called for.
	* cfgrtl.c (fixup_reorder_chain): Remove BARRIERs from fallthru paths.
	(cfg_layout_finalize): Delete dead jump tables before re-building
	the insns chain.
	* ira.c (ira): Rebuild jump labels *after* deleting unreachable
	basic blocks, not before.
	* loop-init.c (rtl_loop_done): Call for an expensive CFG cleanup.

	* modulo-sched.c (sms_schedule): Do not look for BARRIERs in the
	insns chain of a scheduling extended basic block, they cannot appear
	there in cfglayout mode.

From-SVN: r205337

gcc/ChangeLog

+2013-11-24  Steven Bosscher  <steven@gcc.gnu.org>
+
+	* jump.c (reset_insn_reg_label_operand_notes): New function,
+	split out from ...
+	(init_label_info): ... here.  Reset LABEL_NUSES in cfglayout mode.
+	* cfgcleanup.c (delete_dead_jump_tables_between): New function,
+	split out from ...
+	(delete_dead_jumptables): ... here.  Handle cfglayout mode.
+	(cleanup_cfg): Delete dead jump tables in cfglayout mode if an
+	expensive CFG cleanup is called for.
+	* cfgrtl.c (fixup_reorder_chain): Remove BARRIERs from fallthru paths.
+	(cfg_layout_finalize): Delete dead jump tables before re-building
+	the insns chain.
+	* ira.c (ira): Rebuild jump labels *after* deleting unreachable
+	basic blocks, not before.
+	* loop-init.c (rtl_loop_done): Call for an expensive CFG cleanup.
+
+	* modulo-sched.c (sms_schedule): Do not look for BARRIERs in the
+	insns chain of a scheduling extended basic block, they cannot appear
+	there in cfglayout mode.
+
 2013-11-24  Tobias Burnus  <burnus@net-b.de>
 
 	* doc/invoke.texi (-fsanitize=leak): Add link to the wiki page.

gcc/cfgcleanup.c

@@ -2944,40 +2944,65 @@ 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 they are referenced by the preceding
-   insns computing the destination, so we delay deleting and garbagecollect
-   them once life information is computed.  */
+   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.  */
+
 void
 delete_dead_jumptables (void)
 {
   basic_block bb;
 
-  /* A dead jump table does not belong to any basic block.  Scan insns
-     between two adjacent basic blocks.  */
+  /* Label reference count must up-to-date to detect dead jump tables.  */
+  rebuild_jump_labels (get_insns ());
+
   FOR_EACH_BB (bb)
     {
-      rtx insn, next;
-
-      for (insn = NEXT_INSN (BB_END (bb));
-	   insn && !NOTE_INSN_BASIC_BLOCK_P (insn);
-	   insn = next)
+      if (current_ir_type () == IR_RTL_CFGLAYOUT)
 	{
-	  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);
-	    }
+	  /* 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
+	{
+	  /* 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);
 	}
     }
 }
@@ -3049,13 +3074,13 @@ cleanup_cfg (int mode)
   if (mode & CLEANUP_CROSSJUMP)
     remove_fake_exit_edges ();
 
-  /* 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))
+  /* 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))
     delete_dead_jumptables ();
 
   /* ???  We probably do this way too often.  */

gcc/cfgrtl.c

@@ -3696,10 +3696,10 @@ fixup_reorder_chain (void)
 #endif
 
   /* Now add jumps and labels as needed to match the blocks new
-     outgoing edges.  */
+     outgoing edges.  Fixup missing or redundant BARRIERs.  */
 
-  for (bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; bb ; bb = (basic_block)
-       bb->aux)
+  for (bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; bb ;
+       bb = (basic_block) bb->aux)
     {
       edge e_fall, e_taken, e;
       rtx bb_end_insn;
@@ -3853,13 +3853,26 @@ fixup_reorder_chain (void)
 
   relink_block_chain (/*stay_in_cfglayout_mode=*/false);
 
-  /* Annoying special case - jump around dead jumptables left in the code.  */
+  /* Annoying special case - stray barriers left in the code.  This happens
+     if a tablejump is transformed to a simpe or confitional jump, or if a
+     basic block ending in a tablejump is removed but the jump table itself
+     is not.  */
   FOR_EACH_BB (bb)
     {
       edge e = find_fallthru_edge (bb->succs);
 
-      if (e && !can_fallthru (e->src, e->dest))
-	force_nonfallthru (e);
+      if (e && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
+	{
+	  rtx insn, next;
+	  for (insn = NEXT_INSN (BB_END (e->src));
+	       insn != BB_HEAD (e->dest);
+	       insn = next)
+	    {
+	      next = NEXT_INSN (insn);
+	      if (BARRIER_P (insn))
+		remove_insn (insn);
+	    }
+	}
     }
 
   /* Ensure goto_locus from edges has some instructions with that locus
@@ -4273,7 +4286,7 @@ break_superblocks (void)
 }
 
 /* Finalize the changes: reorder insn list according to the sequence specified
-   by aux pointers, enter compensation code, rebuild scope forest.  */
+   by aux pointers, enter compensation code.  */
 
 void
 cfg_layout_finalize (void)
@@ -4281,6 +4294,7 @@ cfg_layout_finalize (void)
 #ifdef ENABLE_CHECKING
   verify_flow_info ();
 #endif
+  delete_dead_jumptables ();
   force_one_exit_fallthru ();
   rtl_register_cfg_hooks ();
   if (reload_completed
@@ -4291,9 +4305,6 @@ cfg_layout_finalize (void)
     fixup_fallthru_exit_predecessor ();
   fixup_reorder_chain ();
 
-  rebuild_jump_labels (get_insns ());
-  delete_dead_jumptables ();
-
 #ifdef ENABLE_CHECKING
   verify_insn_chain ();
   verify_flow_info ();

gcc/ira.c

@@ -5273,9 +5273,9 @@ ira (FILE *f)
   if (optimize && rebuild_p)
     {
       timevar_push (TV_JUMP);
-      rebuild_jump_labels (get_insns ());
       if (purge_all_dead_edges ())
 	delete_unreachable_blocks ();
+      rebuild_jump_labels (get_insns ());
       timevar_pop (TV_JUMP);
     }
 

gcc/jump.c

@@ -177,6 +177,34 @@ make_pass_cleanup_barriers (gcc::context *ctxt)
 }
 
 
+/* Remove all REG_LABEL_OPERAND notes from INSN.
+
+   REG_LABEL_TARGET notes (including the JUMP_LABEL field) are sticky and
+   not reset here; that way we won't lose association with a label when
+   e.g. the source for a target register disappears out of reach for targets
+   that may use jump-target registers.  Jump transformations are supposed to
+   transform any REG_LABEL_TARGET notes.  The target label reference in a
+   branch may disappear from the branch (and from the instruction before it)
+   for other reasons, like register allocation.  */
+
+static void
+reset_insn_reg_label_operand_notes (rtx insn)
+{
+  if (INSN_P (insn))
+    {
+      rtx note, next;
+
+      for (note = REG_NOTES (insn); note; note = next)
+	{
+	  next = XEXP (note, 1);
+	  if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND
+	      && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
+	    remove_note (insn, note);
+	}
+    }
+}
+
+
 /* Initialize LABEL_NUSES and JUMP_LABEL fields, add REG_LABEL_TARGET
    for remaining targets for JUMP_P.  Delete any REG_LABEL_OPERAND
    notes whose labels don't occur in the insn any more.  */
@@ -186,32 +214,38 @@ init_label_info (rtx f)
 {
   rtx insn;
 
-  for (insn = f; insn; insn = NEXT_INSN (insn))
+  if (current_ir_type () == IR_RTL_CFGLAYOUT)
     {
-      if (LABEL_P (insn))
-	LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
-
-      /* REG_LABEL_TARGET notes (including the JUMP_LABEL field) are
-	 sticky and not reset here; that way we won't lose association
-	 with a label when e.g. the source for a target register
-	 disappears out of reach for targets that may use jump-target
-	 registers.  Jump transformations are supposed to transform
-	 any REG_LABEL_TARGET notes.  The target label reference in a
-	 branch may disappear from the branch (and from the
-	 instruction before it) for other reasons, like register
-	 allocation.  */
-
-      if (INSN_P (insn))
+      basic_block bb;
+
+      FOR_EACH_BB (bb)
 	{
-	  rtx note, next;
+	  /* Labels only appear between BB_HEAD and the basic block note,
+	     and in the basic block header and footer.  */
+	  for (insn = BB_HEAD (bb);
+	       insn && LABEL_P (insn);
+	       insn = NEXT_INSN (insn))
+	    LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
+	  for (insn = BB_HEADER (bb); insn; insn = NEXT_INSN (insn))
+	    if (LABEL_P (insn))
+	      LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
+	  for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn))
+	    if (LABEL_P (insn))
+	      LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
 
-	  for (note = REG_NOTES (insn); note; note = next)
-	    {
-	      next = XEXP (note, 1);
-	      if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND
-		  && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
-		remove_note (insn, note);
-	    }
+	  FOR_BB_INSNS (bb, insn)
+	    if (INSN_P (insn))
+	      reset_insn_reg_label_operand_notes (insn);
+	}
+    }
+  else
+    {
+      for (insn = f; insn; insn = NEXT_INSN (insn))
+	{
+	  if (LABEL_P (insn))
+	    LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
+	  if (INSN_P (insn))
+	    reset_insn_reg_label_operand_notes (insn);
 	}
     }
 }

gcc/loop-init.c

@@ -415,7 +415,7 @@ rtl_loop_done (void)
   loop_optimizer_finalize ();
   free_dominance_info (CDI_DOMINATORS);
 
-  cleanup_cfg (0);
+  cleanup_cfg (CLEANUP_EXPENSIVE);
   if (dump_file)
     {
       dump_reg_info (dump_file);

gcc/modulo-sched.c

@@ -1471,7 +1471,7 @@ sms_schedule (void)
 	continue;
       }
 
-      /* Don't handle BBs with calls or barriers
+      /* Don't handle BBs with calls
 	 or !single_set with the exception of instructions that include
 	 count_reg---these instructions are part of the control part
 	 that do-loop recognizes.
@@ -1481,7 +1481,6 @@ sms_schedule (void)
          rtx set;
 
         if (CALL_P (insn)
-            || BARRIER_P (insn)
             || (NONDEBUG_INSN_P (insn) && !JUMP_P (insn)
                 && !single_set (insn) && GET_CODE (PATTERN (insn)) != USE
                 && !reg_mentioned_p (count_reg, insn))
@@ -1496,8 +1495,6 @@ sms_schedule (void)
 	    {
 	      if (CALL_P (insn))
 		fprintf (dump_file, "SMS loop-with-call\n");
-	      else if (BARRIER_P (insn))
-		fprintf (dump_file, "SMS loop-with-barrier\n");
               else if ((NONDEBUG_INSN_P (insn) && !JUMP_P (insn)
                 && !single_set (insn) && GET_CODE (PATTERN (insn)) != USE))
                 fprintf (dump_file, "SMS loop-with-not-single-set\n");