(redundant_insn_p): Change return type to rtx.

(redundant_insn_p): Change return type to rtx.  Return the redundant insn
instead of true.
(update_reg_unused_notes): New function.
(fill_slots_from_thread): Call update_reg_unused_notes after one of the
redundant_insn_p calls.

From-SVN: r8446

diff --git a/gcc/reorg.c b/gcc/reorg.c
index 250cf9971588f942a584f0d4d23b1254f13cb126..9fe88faf116f29bf98084f25006061f17701566d 100644 (file)
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -244,12 +244,13 @@ static rtx steal_delay_list_from_fallthrough PROTO((rtx, rtx, rtx, rtx,
                                                    struct resources *,
                                                    int, int *, int *));
 static void try_merge_delay_insns PROTO((rtx, rtx));
-static int redundant_insn_p    PROTO((rtx, rtx, rtx));
+static rtx redundant_insn_p    PROTO((rtx, rtx, rtx));
 static int own_thread_p                PROTO((rtx, rtx, int));
 static int find_basic_block    PROTO((rtx));
 static void update_block       PROTO((rtx, rtx));
 static int reorg_redirect_jump PROTO((rtx, rtx));
 static void update_reg_dead_notes PROTO((rtx, rtx));
+static void update_reg_unused_notes PROTO((rtx, rtx));
 static void update_live_status PROTO((rtx, rtx));
 static rtx next_insn_no_annul  PROTO((rtx));
 static void mark_target_live_regs PROTO((rtx, struct resources *));
@@ -1922,7 +1923,7 @@ try_merge_delay_insns (insn, thread)
    redundant insn, but the cost of splitting seems greater than the possible
    gain in rare cases.  */
 
-static int
+static rtx
 redundant_insn_p (insn, target, delay_list)
      rtx insn;
      rtx target;
@@ -2079,7 +2080,7 @@ redundant_insn_p (insn, target, delay_list)
                {
                  /* Show that this insn will be used in the sequel.  */
                  INSN_FROM_TARGET_P (candidate) = 0;
-                 return 1;
+                 return candidate;
                }
 
              /* Unless this is an annulled insn from the target of a branch,
@@ -2101,7 +2102,7 @@ redundant_insn_p (insn, target, delay_list)
          /* See if TRIAL is the same as INSN.  */
          pat = PATTERN (trial);
          if (rtx_equal_p (pat, ipat))
-           return 1;
+           return trial;
 
          /* Can't go any further if TRIAL conflicts with INSN.  */
          if (insn_sets_resource_p (trial, &needed, 1))
@@ -2276,6 +2277,33 @@ update_reg_dead_notes (insn, delayed_insn)
          }
       }
 }
+
+/* Delete any REG_UNUSED notes that exist on INSN but not on REDUNDANT_INSN.
+
+   This handles the case of udivmodXi4 instructions which optimize their
+   output depending on whether any REG_UNUSED notes are present.
+   we must make sure that INSN calculates as many results as REDUNDANT_INSN
+   does.  */
+
+static void
+update_reg_unused_notes (insn, redundant_insn)
+     rtx insn, redundant_insn;
+{
+  rtx p, link, next;
+
+  for (link = REG_NOTES (insn); link; link = next)
+    {
+      next = XEXP (link, 1);
+
+      if (REG_NOTE_KIND (link) != REG_UNUSED
+         || GET_CODE (XEXP (link, 0)) != REG)
+       continue;
+
+      if (! find_regno_note (redundant_insn, REG_UNUSED,
+                            REGNO (XEXP (link, 0))))
+       remove_note (insn, link);
+    }
+}
 \f
 /* Marks registers possibly live at the current place being scanned by
    mark_target_live_regs.  Used only by next two function.    */
@@ -3279,10 +3307,12 @@ fill_slots_from_thread (insn, condition, thread, opposite_thread, likely,
 #endif
          )
        {
+         rtx prior_insn;
+
          /* If TRIAL is redundant with some insn before INSN, we don't
             actually need to add it to the delay list; we can merely pretend
             we did.  */
-         if (redundant_insn_p (trial, insn, delay_list))
+         if (prior_insn = redundant_insn_p (trial, insn, delay_list))
            {
              if (own_thread)
                {
@@ -3297,7 +3327,10 @@ fill_slots_from_thread (insn, condition, thread, opposite_thread, likely,
                  delete_insn (trial);
                }
              else
-               new_thread = next_active_insn (trial);
+               {
+                 update_reg_unused_notes (prior_insn, trial);
+                 new_thread = next_active_insn (trial);
+               }
 
              continue;
            }