PR tree-optimization/86659
	* gimple-match.h (struct gimple_match_op): Add reverse field.
	(gimple_match_op::set_op): New overloaded method.
	* gimple-match-head.c (maybe_build_generic_op) <BIT_FIELD_REF>: Set
	the REF_REVERSE_STORAGE_ORDER flag on the value.
	(gimple_simplify) <GIMPLE_ASSIGN>: For BIT_FIELD_REF, propagate the
	REF_REVERSE_STORAGE_ORDER flag and avoid simplifying if it is set.

From-SVN: r264942