Avoid requiring VEC_PERM represenatives

The following plugs one hole where we require a VEC_PERM node
representative unnecessarily.  This is for vect_check_store_rhs
which looks at the RHS and checks whether a constant can be
native encoded.  The fix is to guard that with vect_constant_def
additionally and making vect_is_simple_use forgiving for a missing
SLP_TREE_REPRESENTATIVE when the child is a VEC_PERM node,
initializing the scalar def to error_mark_node.

	* tree-vect-stmts.cc (vect_check_store_rhs): Look at *rhs
	only when it's a vec_constant_def.
	(vect_is_simple_use): When we have no representative for
	an internal node, fill in *op with error_mark_node.

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 672959501bb791abdc2966621a7a57193f183b64..4219ad832db74136282a5b9c0aa1777d10938b4e 100644 (file)
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -2553,7 +2553,8 @@ vect_check_store_rhs (vec_info *vinfo, stmt_vec_info stmt_info,
 
   /* In the case this is a store from a constant make sure
      native_encode_expr can handle it.  */
-  if (CONSTANT_CLASS_P (*rhs) && native_encode_expr (*rhs, NULL, 64) == 0)
+  if (rhs_dt == vect_constant_def
+      && CONSTANT_CLASS_P (*rhs) && native_encode_expr (*rhs, NULL, 64) == 0)
     {
       if (dump_enabled_p ())
        dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@@ -14002,8 +14003,26 @@ vect_is_simple_use (vec_info *vinfo, stmt_vec_info stmt, slp_tree slp_node,
       *vectype = SLP_TREE_VECTYPE (child);
       if (SLP_TREE_DEF_TYPE (child) == vect_internal_def)
        {
-         *op = gimple_get_lhs (SLP_TREE_REPRESENTATIVE (child)->stmt);
-         return vect_is_simple_use (*op, vinfo, dt, def_stmt_info_out);
+         /* ???  VEC_PERM nodes might be intermediate and their lane value
+            have no representative (nor do we build a VEC_PERM stmt for
+            the actual operation).  Note for two-operator nodes we set
+            a representative but leave scalar stmts empty as we'd only
+            have one for a subset of lanes.  Ideally no caller would
+            require *op for internal defs.  */
+         if (SLP_TREE_REPRESENTATIVE (child))
+           {
+             *op = gimple_get_lhs (SLP_TREE_REPRESENTATIVE (child)->stmt);
+             return vect_is_simple_use (*op, vinfo, dt, def_stmt_info_out);
+           }
+         else
+           {
+             gcc_assert (SLP_TREE_CODE (child) == VEC_PERM_EXPR);
+             *op = error_mark_node;
+             *dt = vect_internal_def;
+             if (def_stmt_info_out)
+               *def_stmt_info_out = NULL;
+             return true;
+           }
        }
       else
        {