Remove libcall notes.

	* see.c (see_analyse_one_def): Do not look for REG_LIBCALL and
	REG_RETVAL notes.
	(see_update_relevancy): Likewise.
	* fwprop.c (try_fwprop_subst): Likewise.
	* rtlanal.c (noop_move_p): Likewise.
	* builtins.c (expand_buitlin_mathfn): Don't try to add REG_EQUAL
	notes to non-existing libcall blocks.
	* cse.c (cse_insn): Change prototype.  Don't update libcall notes.
	Remove orig_set.
	(cse_extended_basic_block): Don't track libcall and no-conflict notes.
	(dead_libcall_p): Remove.
	(delete_trivially_dead_insns): Don't use it.
	* web.c (union_defs): Remove comment about keeping nops.
	* gcse.c (hash_scan_insn): Don't take libcall pointers.
	(compute_hash_table_work): Don't track libcall notes.
	(do_local_cprop): Don't take libcall pointers.  Don't update
	libcall notes.
	(adjust_libcall_notes): Deleted.
	(local_cprop_pass): Remove stack for nested libcalls (which shouldn't
	ever have existed in the first place).
	(replace_store_insn): Don't try to remove libcall notes.
	* lower-subreg.c (move_libcall_note, move_retval_note): Deleted.
	(resolve_reg_notes): Don't call them.
	(resolve_simple_move): Likewise.
	(decompose_multiword_subregs): Remove block handling REG_RETVAL notes.
	Don't remove REG_RETVAL notes.
	* emit-rtl.c (try_split): Don't update libcall notes.
	(emit_copy_of_insn_after): Dito.
	* cselib.c (cselib_current_insn_in_libcall): Remove.
	(cselib_process_insn): Don't set/clear it.
	(new_elt_loc_list): Don't record it.
	(cselib_init): Don't initialize it.
	* cselib.c (struct elt_loc_list): Remove in_libcall field.
	* loop-invariant.c (find_invariant_insn): Don't look for libcall
	notes.
	* sched-deps.c (sched_analyze_insn): Don't group libcall blocks.
	(sched_analyze): Don't set up deps->libcall_block_tail_insn.
	(init_deps): Don't initialize it.
	* sched-int.h (struct deps): Rremove libcall_block_tail_insn field.
	* combine.c (delete_noop_moves): Don't update libcall notes.
	(can_combine_p): Remove now pointless #if 0 block.
	(try_combine): Remove another obsolete #if 0 block.
	(distribute_notes): Don't distribute libcall notes.
	* reg-notes.def (REG_LIBCALL, REG_RETVAL): Remove.
	* dce.c (libcall_dead_p): Remove.
	(delete_unmarked_insns): Don't handle libcall blocks.
	(preserve_libcall_for_dce): Remove.
	(prescan_insns_for_dce): Don't special-case libcall block insns.
	* reload1 (reload): Don't handle libcall notes. 
	* doc/rtl.texi (REG_LIBCALL, REG_RETVAL, REG_LIBCALL_ID): Remove
	documentation.

From-SVN: r136861

1 files changed, 1 insertions, 151 deletions

diff --git a/gcc/dce.c b/gcc/dce.c
index 91cc9aa..b75a8b1 100644
--- a/gcc/dce.c
+++ b/gcc/dce.c
@@ -214,62 +214,6 @@ mark_nonreg_stores (rtx body, rtx insn, bool fast)
 }
 
 
-/* Return true if the entire libcall sequence starting at INSN is dead.
-   NOTE is the REG_LIBCALL note attached to INSN.
-
-   A libcall sequence is a block of insns with no side-effects, i.e.
-   that is only used for its return value.  The terminology derives
-   from that of a call, but a libcall sequence need not contain one.
-   It is only defined by a pair of REG_LIBCALL/REG_RETVAL notes.
-
-   From a dataflow viewpoint, a libcall sequence has the property that
-   no UD chain can enter it from the outside.  As a consequence, if a
-   libcall sequence has a dead return value, it is effectively dead.
-   This is both enforced by CSE (cse_extended_basic_block) and relied
-   upon by delete_trivially_dead_insns.
-
-   However, in practice, the return value business is a tricky one and
-   only checking the liveness of the last insn is not sufficient to
-   decide whether the whole sequence is dead (e.g. PR middle-end/19551)
-   so we check the liveness of every insn starting from the call.  */
-
-static bool
-libcall_dead_p (rtx insn, rtx note)
-{
-  rtx last = XEXP (note, 0);
-
-  /* Find the call insn.  */
-  while (insn != last && !CALL_P (insn))
-    insn = NEXT_INSN (insn);
-
-  /* If there is none, do nothing special, since ordinary death handling
-     can understand these insns.  */
-  if (!CALL_P (insn))
-    return false;
-
-  /* If this is a call that returns a value via an invisible pointer, the
-     dataflow engine cannot see it so it has been marked unconditionally.
-     Skip it unless it has been made the last insn in the libcall, for
-     example by the combiner, in which case we're left with no easy way
-     of asserting its liveness.  */
-  if (!single_set (insn))
-    {
-      if (insn == last)
-	return false;
-      insn = NEXT_INSN (insn);
-    }
-
-  while (insn != NEXT_INSN (last))
-    {
-      if (INSN_P (insn) && marked_insn_p (insn))
-	return false;
-      insn = NEXT_INSN (insn);
-    }
-
-  return true;
-}
-
-
 /* Delete all REG_EQUAL notes of the registers INSN writes, to prevent
    bad dangling REG_EQUAL notes. */
 
@@ -316,29 +260,10 @@ delete_unmarked_insns (void)
     FOR_BB_INSNS_SAFE (bb, insn, next)
       if (INSN_P (insn))
 	{
-	  rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
-
 	  /* Always delete no-op moves.  */
 	  if (noop_move_p (insn))
 	    ;
 
-	  /* Try to delete libcall sequences as a whole.  */
-	  else if (note && libcall_dead_p (insn, note))
-	    {
-	      rtx last = XEXP (note, 0);
-
-	      if (!dbg_cnt (dce))
-		continue;
-
-	      if (dump_file)
-	        fprintf (dump_file, "DCE: Deleting libcall %d-%d\n",
-			 INSN_UID (insn), INSN_UID (last));
-
-	      next = NEXT_INSN (last);
-	      delete_insn_chain_and_edges (insn, last);
-	      continue;
-	    }
-
 	  /* Otherwise rely only on the DCE algorithm.  */
 	  else if (marked_insn_p (insn))
 	    continue;
@@ -353,41 +278,6 @@ delete_unmarked_insns (void)
 	     for the destination regs in order to avoid dangling notes.  */
 	  delete_corresponding_reg_eq_notes (insn);
 
-	  /* If we're about to delete the first insn of a libcall, then
-	     move the REG_LIBCALL note to the next real insn and update
-	     the REG_RETVAL note.  */
-	  if (note && (XEXP (note, 0) != insn))
-	    {
-	      rtx new_libcall_insn = next_real_insn (insn);
-	      rtx retval_note = find_reg_note (XEXP (note, 0),
-					       REG_RETVAL, NULL_RTX);
-	      /* If the RETVAL and LIBCALL notes would land on the same
-		 insn just remove them.  */
-	      if (XEXP (note, 0) == new_libcall_insn)
-		remove_note (new_libcall_insn, retval_note);
-	      else
-		{
-		  REG_NOTES (new_libcall_insn)
-		    = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
-					 REG_NOTES (new_libcall_insn));
-		  XEXP (retval_note, 0) = new_libcall_insn;
-		}
-	    }
-
-	  /* If the insn contains a REG_RETVAL note and is dead, but the
-	     libcall as a whole is not dead, then we want to remove the
-	     insn, but not the whole libcall sequence.  However, we also
-	     need to remove the dangling REG_LIBCALL note in order to
-	     avoid mismatched notes.  We could find a new location for
-	     the REG_RETVAL note, but it hardly seems worth the effort.  */
-	  note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
-	  if (note && (XEXP (note, 0) != insn))
-	    {
-	      rtx libcall_note
-		= find_reg_note (XEXP (note, 0), REG_LIBCALL, NULL_RTX);
-	      remove_note (XEXP (note, 0), libcall_note);
-	    }
-
 	  /* If a pure or const call is deleted, this may make the cfg
 	     have unreachable blocks.  We rememeber this and call
 	     delete_unreachable_blocks at the end.  */
@@ -404,43 +294,6 @@ delete_unmarked_insns (void)
 }
 
 
-/* Helper function for prescan_insns_for_dce: prescan the entire libcall
-   sequence starting at INSN and return the insn following the libcall.
-   NOTE is the REG_LIBCALL note attached to INSN.  */
-
-static rtx
-prescan_libcall_for_dce (rtx insn, rtx note, bool fast)
-{
-  rtx last = XEXP (note, 0);
-
-  /* A libcall is never necessary on its own but we need to mark the stores
-     to a non-register destination.  */
-  while (insn != last && !CALL_P (insn))
-    {
-      if (INSN_P (insn))
-	mark_nonreg_stores (PATTERN (insn), insn, fast);
-      insn = NEXT_INSN (insn);
-    }
-
-  /* If this is a call that returns a value via an invisible pointer, the
-     dataflow engine cannot see it so it has to be marked unconditionally.  */
-  if (CALL_P (insn) && !single_set (insn))
-    {
-      mark_insn (insn, fast);
-      insn = NEXT_INSN (insn);
-    }
-
-  while (insn != NEXT_INSN (last))
-    {
-      if (INSN_P (insn))
-	mark_nonreg_stores (PATTERN (insn), insn, fast);
-      insn = NEXT_INSN (insn);
-    }
-
-  return insn;
-}
-
-
 /* Go through the instructions and mark those whose necessity is not
    dependent on inter-instruction information.  Make sure all other
    instructions are not marked.  */
@@ -458,10 +311,7 @@ prescan_insns_for_dce (bool fast)
     FOR_BB_INSNS_SAFE (bb, insn, next)
       if (INSN_P (insn))
 	{
-	  rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
-	  if (note)
-	    next = prescan_libcall_for_dce (insn, note, fast);
-	  else if (deletable_insn_p (insn, fast))
+	  if (deletable_insn_p (insn, fast))
 	    mark_nonreg_stores (PATTERN (insn), insn, fast);
 	  else
 	    mark_insn (insn, fast);