[PATCH][AArch64] Use std::swap instead of manually swapping

[Kyrill Tkachov <kyrylo dot tkachov at arm dot com>]

Hi all,

Following the trend in i386 and alpha, this patch uses std::swap to 
perform swapping of values in the aarch64 backend instead of declaring 
temporaries.
Tested and bootstrapped on aarch64-linux.

Ok for trunk?

Thanks,
Kyrill


2014-11-13  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

    * config/aarch64/aarch64.c (aarch64_evpc_ext): Use std::swap instead
    of manual swapping implementation.
    (aarch64_expand_vec_perm_const_1): Likewise.

commit 20ce59f52c26f99ad3939597c5cd41a0cdc8a751
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date:   Wed Nov 12 15:41:05 2014 +0000

    [AArch64] Use std::swap

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index d1f5673..f92b23a 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -9428,9 +9428,7 @@ aarch64_evpc_ext (struct expand_vec_perm_d *d)
       /* After setup, we want the high elements of the first vector (stored
          at the LSB end of the register), and the low elements of the second
          vector (stored at the MSB end of the register). So swap.  */
-      rtx temp = d->op0;
-      d->op0 = d->op1;
-      d->op1 = temp;
+      std::swap (d->op0, d->op1);
       /* location != 0 (above), so safe to assume (nelt - location) < nelt.  */
       location = nelt - location;
     }
@@ -9601,15 +9599,12 @@ aarch64_expand_vec_perm_const_1 (struct expand_vec_perm_d *d)
   if (d->perm[0] >= d->nelt)
     {
       unsigned i, nelt = d->nelt;
-      rtx x;
 
       gcc_assert (nelt == (nelt & -nelt));
       for (i = 0; i < nelt; ++i)
 	d->perm[i] ^= nelt; /* Keep the same index, but in the other vector.  */
 
-      x = d->op0;
-      d->op0 = d->op1;
-      d->op1 = x;
+      std::swap (d->op0, d->op1);
     }
 
   if (TARGET_SIMD)