[patch] GCC bug patch pr52714

pr52714.patch (text/plain), 2.52 KB, created by Alan Hourihane on 2013-11-08 08:20:14 UTC

[proposed but not yet submitted fix for PR52714 on M68K <[e-mail]>]

gcc/

2012-12-30  Mikael Pettersson  <[e-mail]>

	PR rtl-optimization/52714
	* combine.c (try_combine): Revert to gcc-4.5 version
	of PR rtl-optimization/45695 fix.

--- gcc-4.6.3/gcc/combine.c.~1~	2012-02-09 18:29:38.000000000 +0100
+++ gcc-4.6.3/gcc/combine.c	2012-12-30 16:14:06.000000000 +0100
@@ -3765,41 +3765,42 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx
 	   && GET_CODE (XVECEXP (newpat, 0, 1)) == SET
 	   && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT
 	   && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART
+	   && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)),
+				   DF_INSN_LUID (i2))
 	   && ! reg_referenced_p (SET_DEST (XVECEXP (newpat, 0, 1)),
 				  XVECEXP (newpat, 0, 0))
 	   && ! reg_referenced_p (SET_DEST (XVECEXP (newpat, 0, 0)),
 				  XVECEXP (newpat, 0, 1))
 	   && ! (contains_muldiv (SET_SRC (XVECEXP (newpat, 0, 0)))
-		 && contains_muldiv (SET_SRC (XVECEXP (newpat, 0, 1)))))
+		 && contains_muldiv (SET_SRC (XVECEXP (newpat, 0, 1))))
+#ifdef HAVE_cc0
+	   /* We cannot split the parallel into two sets if both sets
+	      reference cc0.  */
+	   && ! (reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 0))
+		 && reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 1)))
+#endif
+	   )
     {
       /* Normally, it doesn't matter which of the two is done first,
-	 but the one that references cc0 can't be the second, and
-	 one which uses any regs/memory set in between i2 and i3 can't
+	 but it does if one references cc0.  In that case, it has to
 	 be first.  */
-      if (!use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)),
-			      DF_INSN_LUID (i2))
-#ifdef HAVE_cc0
-	  && !reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 0))
-#endif
-	 )
-	{
-	  newi2pat = XVECEXP (newpat, 0, 1);
-	  newpat = XVECEXP (newpat, 0, 0);
-	}
-      else if (!use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 0)),
-				   DF_INSN_LUID (i2))
 #ifdef HAVE_cc0
-	       && !reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 1))
-#endif
-	      )
+      if (reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 0)))
 	{
+	  if (use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 0)),
+				 DF_INSN_LUID (i2)))
+	    {
+	      undo_all ();
+	      return 0;
+	    }
 	  newi2pat = XVECEXP (newpat, 0, 0);
 	  newpat = XVECEXP (newpat, 0, 1);
 	}
       else
+#endif
 	{
-	  undo_all ();
-	  return 0;
+	  newi2pat = XVECEXP (newpat, 0, 1);
+	  newpat = XVECEXP (newpat, 0, 0);
 	}
 
       i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes);