[combine][obvious] Use std::swap instead of manually swapping

	* combine.c (simplify_if_then_else): Use std::swap instead
	of manually swapping.
	(known_cond): Likewise.
	(simplify_comparison): Likewise.

From-SVN: r222468

gcc/ChangeLog

+2015-04-27  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* combine.c (simplify_if_then_else): Use std::swap instead
+	of manually swapping.
+	(known_cond): Likewise.
+	(simplify_comparison): Likewise.
+
 2015-04-27  Peter Bergner  <bergner@vnet.ibm.com>
 
 	PR target/64579

gcc/combine.c

@@ -6194,7 +6194,7 @@ simplify_if_then_else (rtx x)
       if (false_code == EQ)
 	{
 	  swapped = 1, true_code = EQ, false_code = NE;
-	  temp = true_rtx, true_rtx = false_rtx, false_rtx = temp;
+	  std::swap (true_rtx, false_rtx);
 	}
 
       /* If we are comparing against zero and the expression being tested has
@@ -6259,7 +6259,7 @@ simplify_if_then_else (rtx x)
       SUBST (XEXP (x, 1), false_rtx);
       SUBST (XEXP (x, 2), true_rtx);
 
-      temp = true_rtx, true_rtx = false_rtx, false_rtx = temp;
+      std::swap (true_rtx, false_rtx);
       cond = XEXP (x, 0);
 
       /* It is possible that the conditional has been simplified out.  */
@@ -9031,7 +9031,6 @@ static rtx
 known_cond (rtx x, enum rtx_code cond, rtx reg, rtx val)
 {
   enum rtx_code code = GET_CODE (x);
-  rtx temp;
   const char *fmt;
   int i, j;
 
@@ -9071,7 +9070,10 @@ known_cond (rtx x, enum rtx_code cond, rtx reg, rtx val)
   else if (COMPARISON_P (x) || COMMUTATIVE_ARITH_P (x))
     {
       if (rtx_equal_p (XEXP (x, 0), val))
-	cond = swap_condition (cond), temp = val, val = reg, reg = temp;
+        {
+	  std::swap (val, reg);
+	  cond = swap_condition (cond);
+        }
 
       if (rtx_equal_p (XEXP (x, 0), reg) && rtx_equal_p (XEXP (x, 1), val))
 	{
@@ -11448,7 +11450,7 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1)
      is already a constant integer.  */
   if (swap_commutative_operands_p (op0, op1))
     {
-      tem = op0, op0 = op1, op1 = tem;
+      std::swap (op0, op1);
       code = swap_condition (code);
     }
 
@@ -12335,7 +12337,7 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1)
   /* We may have changed the comparison operands.  Re-canonicalize.  */
   if (swap_commutative_operands_p (op0, op1))
     {
-      tem = op0, op0 = op1, op1 = tem;
+      std::swap (op0, op1);
       code = swap_condition (code);
     }