re PR middle-end/39954 (Revision 146817 caused unaligned access in gcc.dg/torture/pr26565.c)

2010-01-18  Richard Guenther  <rguenther@suse.de>

	PR middle-end/39954
	* cfgexpand.c (expand_call_stmt): TER pointer arguments in
	builtin calls.

From-SVN: r156008

gcc/ChangeLog

 2010-01-18  Richard Guenther  <rguenther@suse.de>
 
+	PR middle-end/39954
+	* cfgexpand.c (expand_call_stmt): TER pointer arguments in
+	builtin calls.
+
+2010-01-18  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/42781
 	* tree-ssa-structalias.c (find_what_var_points_to): Skip
 	restrict processing only if the original variable was

gcc/cfgexpand.c

@@ -1746,15 +1746,31 @@ expand_call_stmt (gimple stmt)
   tree exp;
   tree lhs = gimple_call_lhs (stmt);
   size_t i;
+  bool builtin_p;
+  tree decl;
 
   exp = build_vl_exp (CALL_EXPR, gimple_call_num_args (stmt) + 3);
 
   CALL_EXPR_FN (exp) = gimple_call_fn (stmt);
+  decl = gimple_call_fndecl (stmt);
+  builtin_p = decl && DECL_BUILT_IN (decl);
+
   TREE_TYPE (exp) = gimple_call_return_type (stmt);
   CALL_EXPR_STATIC_CHAIN (exp) = gimple_call_chain (stmt);
 
   for (i = 0; i < gimple_call_num_args (stmt); i++)
-    CALL_EXPR_ARG (exp, i) = gimple_call_arg (stmt, i);
+    {
+      tree arg = gimple_call_arg (stmt, i);
+      gimple def;
+      /* TER addresses into arguments of builtin functions so we have a
+	 chance to infer more correct alignment information.  See PR39954.  */
+      if (builtin_p
+	  && TREE_CODE (arg) == SSA_NAME
+	  && (def = get_gimple_for_ssa_name (arg))
+	  && gimple_assign_rhs_code (def) == ADDR_EXPR)
+	arg = gimple_assign_rhs1 (def);
+      CALL_EXPR_ARG (exp, i) = arg;
+    }
 
   if (gimple_has_side_effects (stmt))
     TREE_SIDE_EFFECTS (exp) = 1;