2010-06-08  Sandra Loosemore  <sandra@codesourcery.com>

	PR tree-optimization/39874
	PR middle-end/28685

	gcc/
	* gimple.h (maybe_fold_and_comparisons, maybe_fold_or_comparisons):
	Declare.
	* gimple-fold.c (canonicalize_bool, same_bool_comparison_p,
	same_bool_result_p): New.
	(and_var_with_comparison, and_var_with_comparison_1,
	and_comparisons_1, and_comparisons, maybe_fold_and_comparisons): New.
	(or_var_with_comparison, or_var_with_comparison_1,
	or_comparisons_1, or_comparisons, maybe_fold_or_comparisons): New.
	* tree-ssa-reassoc.c (eliminate_redundant_comparison): Use
	maybe_fold_and_comparisons or maybe_fold_or_comparisons instead
	of combine_comparisons.
	* tree-ssa-ifcombine.c (ifcombine_ifandif, ifcombine_iforif): Likewise.

	gcc/testsuite/
	* gcc.dg/pr39874.c: New file.

From-SVN: r160445