2008-08-10  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR middle-end/20644
	* tree-ssa.c (struct walk_data): Add new flag
	warn_possibly_uninitialized.
	(warn_uninitialized_var): Use it.
	(warn_uninitialized_vars): New.
	(execute_early_warn_uninitialized): Call it.
	(execute_late_warn_uninitialized): Likewise.
testsuite/
	* gcc.dg/uninit-pr20644-O0.c: New.
	* gcc.dg/uninit-pr20644.c: New.

From-SVN: r138933