[AArch64] Fix bootstrap due to wide_int .elt (0) uninit warning

    * config/aarch64/aarch64.c (aarch64_float_const_representable_p):
    Use wide_int::ulow () instead of .elt (0).

From-SVN: r245877

gcc/ChangeLog

+2017-03-03  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/aarch64/aarch64.c (aarch64_float_const_representable_p):
+	Use wide_int::ulow () instead of .elt (0).
+
 2017-03-03  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.md (*pushtf): Change *roF constraint to *roC.

gcc/config/aarch64/aarch64.c

@@ -12496,7 +12496,7 @@ aarch64_float_const_representable_p (rtx x)
 
   /* If the low part of the mantissa has bits set we cannot represent
      the value.  */
-  if (w.elt (0) != 0)
+  if (w.ulow () != 0)
     return false;
   /* We have rejected the lower HOST_WIDE_INT, so update our
      understanding of how many bits lie in the mantissa and