genmatch.c (enum tree_code): Remove CONVERT{0,1,2} and VIEW_CONVERT{0,1,2}.

genmatch.c (enum tree_code): Remove CONVERT{0,1,2} and VIEW_CONVERT{0,1,2}.

2019-12-06  Richard Biener  <rguenther@suse.de>

	* genmatch.c (enum tree_code): Remove CONVERT{0,1,2} and
	VIEW_CONVERT{0,1,2}.
	(expr::opt_grp): Add and initialize.
	(lower_opt_convert): Rename to ...
	(lower_opt): ... and work on opt_grp, simply switching operations
	from being optional to being present or not.
	(has_opt_convert): Rename to ...
	(has_opt): ... and adjust.
	(parser::parse_operation): Return the optional opt_grp,
	remove special-casing of conditional operations and more generally
	parse [digit]'?'.
	(parser::parse_expr): Stick on the parsed opt_grp and perform
	rough verification.
	(parser::parse_for): Remove now unnecessary code.
	(main): Likewise.
	* doc/match-and-simplify.texi: Mention ? now works on all
	unary operations and also match predicates.

From-SVN: r279037