gimple-fold.c (gimple_fold_builtin_memory_op): Make sure to fold the RHS to a constant if possible.

2016-06-10  Richard Biener  <rguenther@suse.de>

	* gimple-fold.c (gimple_fold_builtin_memory_op): Make sure
	to fold the RHS to a constant if possible.

From-SVN: r237301

gcc/ChangeLog

+2016-06-10  Richard Biener  <rguenther@suse.de>
+
+	* gimple-fold.c (gimple_fold_builtin_memory_op): Make sure
+	to fold the RHS to a constant if possible.
+
 2016-06-10  Thomas Schwinge  <thomas@codesourcery.com>
 
 	PR middle-end/71373

gcc/gimple-fold.c

@@ -1020,14 +1020,20 @@ gimple_fold_builtin_memory_op (gimple_stmt_iterator *gsi,
       gimple *new_stmt;
       if (is_gimple_reg_type (TREE_TYPE (srcvar)))
 	{
-	  new_stmt = gimple_build_assign (NULL_TREE, srcvar);
-	  if (gimple_in_ssa_p (cfun))
-	    srcvar = make_ssa_name (TREE_TYPE (srcvar), new_stmt);
-	  else
-	    srcvar = create_tmp_reg (TREE_TYPE (srcvar));
-	  gimple_assign_set_lhs (new_stmt, srcvar);
-	  gimple_set_vuse (new_stmt, gimple_vuse (stmt));
-	  gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
+	  tree tem = fold_const_aggregate_ref (srcvar);
+	  if (tem)
+	    srcvar = tem;
+	  if (! is_gimple_min_invariant (srcvar))
+	    {
+	      new_stmt = gimple_build_assign (NULL_TREE, srcvar);
+	      if (gimple_in_ssa_p (cfun))
+		srcvar = make_ssa_name (TREE_TYPE (srcvar), new_stmt);
+	      else
+		srcvar = create_tmp_reg (TREE_TYPE (srcvar));
+	      gimple_assign_set_lhs (new_stmt, srcvar);
+	      gimple_set_vuse (new_stmt, gimple_vuse (stmt));
+	      gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
+	    }
 	}
       new_stmt = gimple_build_assign (destvar, srcvar);
       gimple_set_vuse (new_stmt, gimple_vuse (stmt));