[PATCH, rs6000] Correct unaligned_load vector cost for Power9

[Pat Haugen]

Power9 has efficient unaligned load insns. The following patch fixes the
cost to reflect that. There was no similar code for the unaligned_store
case.  Bootstrap/regtest on powerpc64le-linux with no new regressions.
Ok for trunk?

-Pat


2017-10-09  Pat Haugen  <pthau...@us.ibm.com>

        * config/rs6000/power9.c (rs6000_builtin_vectorization_cost): Remove
        TARGET_P9_VECTOR code for unaligned_load case.


Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c  (revision 253547)
+++ gcc/config/rs6000/rs6000.c  (working copy)
@@ -5438,9 +5438,6 @@ rs6000_builtin_vectorization_cost (enum
         return 3;

       case unaligned_load:
-       if (TARGET_P9_VECTOR)
-         return 3;
-
        if (TARGET_EFFICIENT_UNALIGNED_VSX)
          return 1;