reload1.c (move2add_last_cc0): New.

	* reload1.c (move2add_last_cc0): New.
	(reload_cse_move2add): Detect implicit sets.
	(move2add_note_store): Notice a store into cc0.

From-SVN: r65754

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7beb2fc52a26db7c030c11842ae97989aecfa33a..df58352d177b71ae4b4e49d24e4246ede44da54b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2003-04-17  Kazu Hirata  <kazu@cs.umass.edu>
+
+       * reload1.c (move2add_last_cc0): New.
+       (reload_cse_move2add): Detect implicit sets.
+       (move2add_note_store): Notice a store into cc0.
+
 2003-04-17  Roger Sayle  <roger@eyesopen.com>
 
        PR c/10375

diff --git a/gcc/reload1.c b/gcc/reload1.c
index 54d163ee00ce0cbb9e66e2f7427fe1200f043311..83456130534fd139132a927eb899798e679e4d28 100644 (file)
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -9094,6 +9094,9 @@ static int move2add_last_label_luid;
        && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (OUTMODE), \
                                 GET_MODE_BITSIZE (INMODE))))
 
+/* The source of the last set to cc0 we've seen.  */
+static rtx move2add_last_cc0;
+
 static void
 reload_cse_move2add (first)
      rtx first;
@@ -9106,6 +9109,7 @@ reload_cse_move2add (first)
 
   move2add_last_label_luid = 0;
   move2add_luid = 2;
+  move2add_last_cc0 = NULL_RTX;
   for (insn = first; insn; insn = NEXT_INSN (insn), move2add_luid++)
     {
       rtx pat, note;
@@ -9288,6 +9292,29 @@ reload_cse_move2add (first)
            }
        }
       note_stores (PATTERN (insn), move2add_note_store, NULL);
+
+      /* If INSN is a conditional branch, we try to extract an
+        implicit set out of it.  */
+      if (any_condjump_p (insn) && onlyjump_p (insn))
+       {
+         rtx cnd = get_condition (insn, NULL);
+
+#ifdef HAVE_cc0
+         if (cnd != NULL_RTX && move2add_last_cc0 != NULL_RTX)
+           cnd = simplify_replace_rtx (cnd, cc0_rtx, move2add_last_cc0);
+#endif
+         if (cnd != NULL_RTX
+             && GET_CODE (cnd) == NE
+             && GET_CODE (XEXP (cnd, 0)) == REG
+             && SCALAR_INT_MODE_P (GET_MODE (XEXP (cnd, 0)))
+             && GET_CODE (XEXP (cnd, 1)) == CONST_INT)
+           {
+             rtx implicit_set =
+               gen_rtx_SET (VOIDmode, SET_DEST (cnd), SET_SRC (cnd));
+             move2add_note_store (SET_DEST (implicit_set), implicit_set, 0);
+           }
+       }
+
       /* If this is a CALL_INSN, all call used registers are stored with
         unknown values.  */
       if (GET_CODE (insn) == CALL_INSN)
@@ -9334,6 +9361,13 @@ move2add_note_store (dst, set, data)
        reg_set_luid[REGNO (XEXP (dst, 0))] = 0;
       return;
     }
+  /* Note a store into cc0 so that we can later find an implicit
+     set.  */
+  if (CC0_P (dst))
+    {
+      move2add_last_cc0 = SET_SRC (set);
+      return;
+    }
   if (GET_CODE (dst) != REG)
     return;