2008-03-28  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/30317
	PR tree-optimization/30911
	PR tree-optimization/34793
	* tree-vrp.c (set_and_canonicalize_value_range): New function.
	(struct assert_locus_d): New member EXPR.
	(register_new_assert_for): Add EXPR parameter to support
	ASSERT_EXPR <name, expr OP limit>.
	(register_edge_assert_for_1): Adjust callers.
	(find_assert_locations): Likewise.
	(process_assert_insertions_for): Build condition from
	expression.
	(extract_range_from_assert): Handle ASSERT_EXPRs
	of the form ASSERT_EXPR <name, expr OP limit>.
	(register_edge_assert_for_2): New helper registering
	asserts for comparisons.  Recognize range tests of the form
	(unsigned)i - CST1 OP CST2.
	(register_edge_assert_for_1): Use it.
	(register_edge_assert_for): Likewise.
	* tree.def (ASSERT_EXPR): Document extra allowed conditional
	expressions.
	(needs_overflow_infinity): Integer sub-types
	do not need overflow infinities.
	(vrp_val_is_max): The extreme values of integer sub-types
	are those of the base type.
	(vrp_val_is_min): Likewise.

	* gcc.dg/tree-ssa/vrp35.c: New testcase.
	* gcc.dg/tree-ssa/vrp36.c: Likewise.
	* gcc.dg/tree-ssa/vrp37.c: Likewise.

From-SVN: r133680