combine.c (refresh_blocks, [...]): New.

        * combine.c (refresh_blocks, need_refresh): New.
        (combine_instructions): Allocate refresh_blocks.  Invoke
        update_life_info if needed.
        (distribute_notes): Mark refresh_blocks instead of installing
        USE insns.
        * flow.c (update_life_info): Remove notes if GLOBAL_RM_NOTES.
        * basic_block.h (enum update_life_extent): Add GLOBAL_RM_NOTES.

        * Makefile.in (recog.o): Depend on basic-block.h.

From-SVN: r29893

gcc/ChangeLog

+Sun Oct 10 16:14:16 1999  Richard Henderson  <rth@cygnus.com>
+
+	* combine.c (refresh_blocks, need_refresh): New.
+	(combine_instructions): Allocate refresh_blocks.  Invoke
+	update_life_info if needed.
+	(distribute_notes): Mark refresh_blocks instead of installing
+	USE insns.
+	* flow.c (update_life_info): Remove notes if GLOBAL_RM_NOTES.
+	* basic_block.h (enum update_life_extent): Add GLOBAL_RM_NOTES.
+
+	* Makefile.in (recog.o): Depend on basic-block.h.
+
 Sun Oct 10 12:03:21 1999  Richard Henderson  <rth@cygnus.com>
 
 	* genrecog.c (add_to_sequence): Thinko last change: delete

gcc/Makefile.in

@@ -1593,7 +1593,7 @@ final.o : final.c $(CONFIG_H) system.h $(RTL_H) $(TREE_H) flags.h intl.h \
    dbxout.h
 recog.o : recog.c $(CONFIG_H) system.h $(RTL_H) function.h \
    $(REGS_H) $(RECOG_H) hard-reg-set.h flags.h insn-config.h insn-attr.h \
-   insn-flags.h insn-codes.h real.h toplev.h output.h resource.h
+   insn-flags.h insn-codes.h real.h toplev.h output.h resource.h basic-block.h
 reg-stack.o : reg-stack.c $(CONFIG_H) system.h $(RTL_H) $(TREE_H) recog.h \
    $(REGS_H) hard-reg-set.h flags.h insn-config.h insn-flags.h toplev.h \
    varray.h function.h

gcc/basic-block.h

@@ -301,8 +301,9 @@ extern void compute_immediate_dominators	PROTO ((int *, sbitmap *));
 
 enum update_life_extent
 {
-  UPDATE_LIFE_GLOBAL = 0,
-  UPDATE_LIFE_LOCAL = 1
+  UPDATE_LIFE_LOCAL = 0,
+  UPDATE_LIFE_GLOBAL = 1,
+  UPDATE_LIFE_GLOBAL_RM_NOTES = 2,
 };
 
 extern void update_life_info	PROTO ((sbitmap, enum update_life_extent));

gcc/combine.c

@@ -196,6 +196,12 @@ static rtx added_links_insn;
 
 /* Basic block number of the block in which we are performing combines.  */
 static int this_basic_block;
+
+/* A bitmap indicating which blocks had registers go dead at entry.  
+   After combine, we'll need to re-do global life analysis with 
+   those blocks as starting points.  */
+static sbitmap refresh_blocks;
+static int need_refresh;
 
 /* The next group of arrays allows the recording of the last value assigned
    to (hard or pseudo) register n.  We use this information to see if a
@@ -551,6 +557,10 @@ combine_instructions (f, nregs)
 
   setup_incoming_promotions ();
 
+  refresh_blocks = sbitmap_alloc (n_basic_blocks);
+  sbitmap_zero (refresh_blocks);
+  need_refresh = 0;
+
   for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
     {
       uid_cuid[INSN_UID (insn)] = ++i;
@@ -685,6 +695,10 @@ combine_instructions (f, nregs)
 	}
     }
 
+  if (need_refresh)
+    update_life_info (refresh_blocks, UPDATE_LIFE_GLOBAL_RM_NOTES);
+  sbitmap_free (refresh_blocks);
+
   total_attempts += combine_attempts;
   total_merges += combine_merges;
   total_extras += combine_extras;
@@ -11858,30 +11872,15 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
 	      /* We haven't found an insn for the death note and it
 		 is still a REG_DEAD note, but we have hit the beginning
 		 of the block.  If the existing life info says the reg
-		 was dead, there's nothing left to do.
-
-		 ??? If the register was live, we ought to mark for later
-		 global life update.  Cop out like the previous code and
-		 just add a hook for the death note to live on.  */
+		 was dead, there's nothing left to do.  Otherwise, we'll
+		 need to do a global life update after combine.  */
 	      if (REG_NOTE_KIND (note) == REG_DEAD && place == 0)
 		{
 		  int regno = REGNO (XEXP (note, 0));
-
 		  if (REGNO_REG_SET_P (bb->global_live_at_start, regno))
 		    {
-		      rtx die = gen_rtx_USE (VOIDmode, XEXP (note, 0));
-
-		      place = bb->head;
-		      if (GET_CODE (place) != CODE_LABEL
-			  && GET_CODE (place) != NOTE)
-			{
-			  place = emit_insn_before (die, place);
-			  bb->head = place;
-			}
-		      else
-			{
-			  place = emit_insn_after (die, place);
-			}
+		      SET_BIT (refresh_blocks, this_basic_block);
+		      need_refresh = 1;
 		    }
 		}
 	    }

gcc/flow.c

@@ -2554,9 +2554,9 @@ verify_local_live_at_start (new_live_at_start, bb)
    lose the kill.  So we _can_ have a pseudo go live.  How irritating.  */
 
 void
-update_life_info (blocks, local_only)
+update_life_info (blocks, extent)
      sbitmap blocks;
-     enum update_life_extent local_only;
+     enum update_life_extent extent;
 {
   regset tmp;
   int i;
@@ -2565,8 +2565,14 @@ update_life_info (blocks, local_only)
   tmp = ALLOCA_REG_SET ();
 
   /* For a global update, we go through the relaxation process again.  */
-  if (! local_only)
-    calculate_global_regs_live (blocks, blocks, 0);
+  if (extent != UPDATE_LIFE_LOCAL)
+    {
+      calculate_global_regs_live (blocks, blocks, 0);
+
+      /* If asked, remove notes from the blocks we'll update.  */
+      if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
+	count_or_remove_death_notes (blocks, 1);
+    }
 
   EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
     {
@@ -2576,7 +2582,7 @@ update_life_info (blocks, local_only)
       propagate_block (tmp, bb->head, bb->end, (regset) NULL, i,
 		       PROP_DEATH_NOTES);
 
-      if (local_only)
+      if (extent == UPDATE_LIFE_LOCAL)
 	verify_local_live_at_start (tmp, bb);
 
       CLEAN_ALLOCA;