re PR rtl-optimization/45695 (-O1 wrong-code by cmove)

	PR rtl-optimization/45695
	* combine.c (try_combine): When splitting a two set pattern,
	make sure the pattern which will be put into i2 doesn't use REGs
	or MEMs set by insns in between i2 and i3.

	* gcc.c-torture/execute/pr45695.c: New test.

From-SVN: r164431

gcc/ChangeLog

+2010-09-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/45695
+	* combine.c (try_combine): When splitting a two set pattern,
+	make sure the pattern which will be put into i2 doesn't use REGs
+	or MEMs set by insns in between i2 and i3.
+
 2010-09-19  Jan Hubicka  <jh@suse.cz>
 
 	PR lto/44246

gcc/combine.c

@@ -3690,36 +3690,41 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p)
 	   && 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))))
-#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
-	   )
+		 && contains_muldiv (SET_SRC (XVECEXP (newpat, 0, 1)))))
     {
       /* Normally, it doesn't matter which of the two is done first,
-	 but it does if one references cc0.  In that case, it has to
+	 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
 	 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
-      if (reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 0)))
+	       && !reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 1))
+#endif
+	      )
 	{
 	  newi2pat = XVECEXP (newpat, 0, 0);
 	  newpat = XVECEXP (newpat, 0, 1);
 	}
       else
-#endif
 	{
-	  newi2pat = XVECEXP (newpat, 0, 1);
-	  newpat = XVECEXP (newpat, 0, 0);
+	  undo_all ();
+	  return 0;
 	}
 
       i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes);
@@ -3735,44 +3740,11 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p)
 		  {
 		    rtx reg = XEXP (XVECEXP (newi2pat, 0, i), 0);
 		    if (reg_overlap_mentioned_p (reg, newpat))
-		      break;
+		      {
+			undo_all ();
+			return 0;
+		      }
 		  }
-
-	      if (i >= 0)
-		{
-		  /* CLOBBERs on newi2pat prevent it going first.
-		     Try the other order of the insns if possible.  */
-		  temp = newpat;
-		  newpat = XVECEXP (newi2pat, 0, 0);
-		  newi2pat = temp;
-#ifdef HAVE_cc0
-		  if (reg_referenced_p (cc0_rtx, newpat))
-		    {
-		      undo_all ();
-		      return 0;
-		    }
-#endif
-
-		  i2_code_number = recog_for_combine (&newi2pat, i2,
-						      &new_i2_notes);
-		  if (i2_code_number < 0)
-		    {
-		      undo_all ();
-		      return 0;
-		    }
-
-		  if (GET_CODE (newi2pat) == PARALLEL)
-		    for (i = XVECLEN (newi2pat, 0) - 1; i >= 0; i--)
-		      if (GET_CODE (XVECEXP (newi2pat, 0, i)) == CLOBBER)
-			{
-			  rtx reg = XEXP (XVECEXP (newi2pat, 0, i), 0);
-			  if (reg_overlap_mentioned_p (reg, newpat))
-			    {
-			      undo_all ();
-			      return 0;
-			    }
-			}
-		}
 	    }
 
 	  insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes);

gcc/testsuite/ChangeLog

+2010-09-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/45695
+	* gcc.c-torture/execute/pr45695.c: New test.
+
 2010-09-19  Jan Hubicka  <jh@suse.cz>
 
 	PR lto/44246

gcc/testsuite/gcc.c-torture/execute/pr45695.c

+/* PR rtl-optimization/45695 */
+
+extern void abort (void);
+
+__attribute__((noinline)) void
+g (int x)
+{
+  asm volatile ("" : "+r" (x));
+}
+
+__attribute__((noinline)) int
+f (int a, int b, int d)
+{
+  int r = -1;
+  b += d;
+  if (d == a)
+    r = b - d;
+  g (b);
+  return r;
+}
+
+int
+main (void)
+{
+  int l;
+  asm ("" : "=r" (l) : "0" (0));
+  if (f (l + 0, l + 1, l + 4) != -1)
+    abort ();
+  if (f (l + 4, l + 1, l + 4) != 1)
+    abort ();
+  return 0;
+}