The following patch fixes

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65710

The patch was bootstrapped and tested on x86/x86-64, ppc64, and aarch64.

The patch does not contain the test as it is too big.  If it is reduced, 
the test can be committed.

Committed as rev. 221956.

I am also submitting analogous patch to gcc-4.9 branch.

2015-04-09  Vladimir Makarov  <vmakarov@redhat.com>

         PR target/65710
         * lra-int.h (lra_bad_spill_regno_start): New.
         * lra.c (lra_bad_spill_regno_start): New.
         (lra): Set up lra_bad_spill_regno_start.  Set up
         lra_constraint_new_regno_start unconditionally.
         * lra-assigns.c (spill_for): Use lra_bad_spill_regno_start for
         spill preferences.