[PATCH, PowerPC] altivec_expand_vec_perm_const selects wrong field for splat in LE mode

[Bill Schmidt]

This patch fixes another small little-endian problem with vectors on
PowerPC.  Element numbering is reversed when selecting a field for a
vector splat operation.  Fixing this removes a regression from the test
suite when run in LE mode (gcc.dg/vect/slp-perm-3.c).

Patch by Anton Blanchard.  Bootstrapped and tested on
powerpc64-unknown-linux-gnu with no new regressions.  Ok for trunk?

Thanks,
Bill


2013-07-23  Bill Schmidt  <wschm...@linux.vnet.ibm.com>
            Anton Blanchard <an...@au1.ibm.com>

        * config/rs6000/rs6000.c (altivec_expand_vec_perm_const): Correct
        selection of field for vector splat in little endian mode.


Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c  (revision 201149)
+++ gcc/config/rs6000/rs6000.c  (working copy)
@@ -28460,9 +28460,10 @@ altivec_expand_vec_perm_const (rtx operands[4])
              break;
          if (i == 16)
            {
+             int field = BYTES_BIG_ENDIAN ? elt / 2 : 7 - elt / 2;
              x = gen_reg_rtx (V8HImode);
              emit_insn (gen_altivec_vsplth (x, gen_lowpart (V8HImode, op0),
-                                            GEN_INT (elt / 2)));
+                                            GEN_INT (field)));
              emit_move_insn (target, gen_lowpart (V16QImode, x));
              return true;
            }
@@ -28478,9 +28479,10 @@ altivec_expand_vec_perm_const (rtx operands[4])
              break;
          if (i == 16)
            {
+             int field = BYTES_BIG_ENDIAN ? elt / 4 : 3 - elt / 4;
              x = gen_reg_rtx (V4SImode);
              emit_insn (gen_altivec_vspltw (x, gen_lowpart (V4SImode, op0),
-                                            GEN_INT (elt / 4)));
+                                            GEN_INT (field)));
              emit_move_insn (target, gen_lowpart (V16QImode, x));
              return true;
            }