[PATCH, rs6000] gimple folding support for vec_pack and vec_unpack

[Will Schmidt]

Hi,
  Add support for gimple folding for vec_pack(), vec_unpackh() and
vec_unpackl().
Testcases for vec_pack are already in tree. Tests for vec_unpack
have been posted separately.
OK for trunk?
    
Thanks,
-Will

[gcc]
    
2018-07-09 Will Schmidt  <will_schm...@vnet.ibm.com>

        * config/rs6000/rs6000.c (rs6000_gimple_fold_builtin):
        Add support for gimple-folding of vec_pack() and vec_unpack()
        intrinsics.


diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 774c60a..1335661 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -16100,10 +16100,65 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
     case VSX_BUILTIN_XXMRGHW_4SI:
     case ALTIVEC_BUILTIN_VMRGHB:
     case VSX_BUILTIN_VEC_MERGEH_V2DI:
        fold_mergehl_helper (gsi, stmt, 0);
        return true;
+
+    /* d = vec_pack (a, b) */
+    case P8V_BUILTIN_VPKUDUM:
+    case ALTIVEC_BUILTIN_VPKUHUM:
+    case ALTIVEC_BUILTIN_VPKUWUM:
+      {
+       arg0 = gimple_call_arg (stmt, 0);
+       arg1 = gimple_call_arg (stmt, 1);
+       lhs = gimple_call_lhs (stmt);
+       gimple *g = gimple_build_assign (lhs, VEC_PACK_TRUNC_EXPR, arg0, arg1);
+       gimple_set_location (g, gimple_location (stmt));
+       gsi_replace (gsi, g, true);
+       return true;
+      }
+
+   /* d = vec_unpackh (a) */
+   /* Note that the UNPACK_{HI,LO}_EXPR used in the gimple_build_assign call
+      in this code is sensitive to endian-ness, and needs to be inverted to
+      handle both LE and BE targets.  */
+    case ALTIVEC_BUILTIN_VUPKHSB:
+    case ALTIVEC_BUILTIN_VUPKHSH:
+    case P8V_BUILTIN_VUPKHSW:
+      {
+       arg0 = gimple_call_arg (stmt, 0);
+       lhs = gimple_call_lhs (stmt);
+       if (BYTES_BIG_ENDIAN)
+        g = gimple_build_assign (lhs, VEC_UNPACK_HI_EXPR, arg0);
+       else
+        g = gimple_build_assign (lhs, VEC_UNPACK_LO_EXPR, arg0);
+       gimple_set_location (g, gimple_location (stmt));
+       gsi_replace (gsi, g, true);
+       return true;
+      }
+   /* d = vec_unpackl (a) */
+    case ALTIVEC_BUILTIN_VUPKLSB:
+    case ALTIVEC_BUILTIN_VUPKLSH:
+    case P8V_BUILTIN_VUPKLSW:
+      {
+       arg0 = gimple_call_arg (stmt, 0);
+       lhs = gimple_call_lhs (stmt);
+       if (BYTES_BIG_ENDIAN)
+        g = gimple_build_assign (lhs, VEC_UNPACK_LO_EXPR, arg0);
+       else
+        g = gimple_build_assign (lhs, VEC_UNPACK_HI_EXPR, arg0);
+       gimple_set_location (g, gimple_location (stmt));
+       gsi_replace (gsi, g, true);
+       return true;
+      }
+    /* There is no gimple type corresponding with pixel, so just return.  */
+    case ALTIVEC_BUILTIN_VUPKHPX:
+    case ALTIVEC_BUILTIN_VUPKLPX:
+      {
+       return false;
+      }
+
     default:
       if (TARGET_DEBUG_BUILTIN)
        fprintf (stderr, "gimple builtin intrinsic not matched:%d %s %s\n",
                 fn_code, fn_name1, fn_name2);
       break;