re PR tree-optimization/64950 (postpone expanding va_arg till pass_stdarg)

	PR tree-optimization/64950
	Revert:
	2010-08-02  Uros Bizjak  <ubizjak@gmail.com>

	PR target/41089
	* config/alpha/alpha.c (alpha_build_builtin_va_list): Mark __offset
	as volatile.

From-SVN: r222257

gcc/ChangeLog

+2015-04-21  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR tree-optimization/64950
+	Revert:
+	2010-08-02  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR target/41089
+	* config/alpha/alpha.c (alpha_build_builtin_va_list): Mark __offset
+	as volatile.
+
 2015-04-20  Shiva Chen  <shiva0217@gmail.com>
 
 	PR rtl-optimization/64916
@@ -15,7 +25,7 @@
 	* tree-ssa-threadupdate.c (redirection_block_p): Remove
 	redundant test for GIMPLE_ASSIGN in last change.
 
-2015-04-19  Uros Bizjak  <ubizjak@gmail.com>
+2015-04-20  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.c (set_pic_reg_ever_live): Remove.
 	(legitimize_pic_address): Do not call set_pic_reg_ever_live.

gcc/config/alpha/alpha.c

@@ -5957,10 +5957,6 @@ alpha_build_builtin_va_list (void)
 		    integer_type_node);
   DECL_FIELD_CONTEXT (ofs) = record;
   DECL_CHAIN (ofs) = space;
-  /* ??? This is a hack, __offset is marked volatile to prevent
-     DCE that confuses stdarg optimization and results in
-     gcc.c-torture/execute/stdarg-1.c failure.  See PR 41089.  */
-  TREE_THIS_VOLATILE (ofs) = 1;
 
   base = build_decl (BUILTINS_LOCATION,
 		     FIELD_DECL, get_identifier ("__base"),