Mark transaction begin as returns-twice.

	PR rtl-optimization/51771
	gcc/
	* builtin-attrs.def (ATTR_RETURNS_TWICE, ATTR_TM_NOTHROW_RT_LIST):
	New.
	* gtm-builtins.def (BUILT_IN_TM_START): Add returns-twice attrib.

From-SVN: r182937

gcc/ChangeLog

+2012-01-06  Torvald Riegel  <triegel@redhat.com>
+
+	PR rtl-optimization/51771
+	* builtin-attrs.def (ATTR_RETURNS_TWICE, ATTR_TM_NOTHROW_RT_LIST):
+	New.
+	* gtm-builtins.def (BUILT_IN_TM_START): Add returns-twice attrib.
+
 2012-01-05  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR tree-optimization/51315

gcc/builtin-attrs.def

@@ -98,6 +98,7 @@ DEF_ATTR_IDENT (ATTR_STRFTIME, "strftime")
 DEF_ATTR_IDENT (ATTR_TYPEGENERIC, "type generic")
 DEF_ATTR_IDENT (ATTR_TM_REGPARM, "*tm regparm")
 DEF_ATTR_IDENT (ATTR_TM_TMPURE, "transaction_pure")
+DEF_ATTR_IDENT (ATTR_RETURNS_TWICE, "returns_twice")
 
 DEF_ATTR_TREE_LIST (ATTR_NOVOPS_LIST, ATTR_NOVOPS, ATTR_NULL, ATTR_NULL)
 
@@ -241,6 +242,8 @@ DEF_ATTR_TREE_LIST (ATTR_TM_NORETURN_NOTHROW_LIST,
 		    ATTR_TM_REGPARM, ATTR_NULL, ATTR_NORETURN_NOTHROW_LIST)
 DEF_ATTR_TREE_LIST (ATTR_TM_CONST_NOTHROW_LIST,
 		    ATTR_TM_REGPARM, ATTR_NULL, ATTR_CONST_NOTHROW_LIST)
+DEF_ATTR_TREE_LIST (ATTR_TM_NOTHROW_RT_LIST,
+		    ATTR_RETURNS_TWICE, ATTR_NULL, ATTR_TM_NOTHROW_LIST)
 
 /* Same attributes used for BUILT_IN_MALLOC except with TM_PURE thrown in.  */
 DEF_ATTR_TREE_LIST (ATTR_TMPURE_MALLOC_NOTHROW_LIST,

gcc/gtm-builtins.def

 DEF_TM_BUILTIN (BUILT_IN_TM_START, "_ITM_beginTransaction",
-		BT_FN_UINT_UINT, ATTR_TM_NOTHROW_LIST)
+		BT_FN_UINT_UINT, ATTR_TM_NOTHROW_RT_LIST)
 
 DEF_TM_BUILTIN (BUILT_IN_TM_COMMIT, "_ITM_commitTransaction",
 		BT_FN_VOID, ATTR_TM_NOTHROW_LIST)