md.texi (automata_option): Document collapse-ndfa.

	* doc/md.texi (automata_option): Document collapse-ndfa.
	* genautomata.c (COLLAPSE_OPTION): New macro.
	(collapse_flag): New static variable.
	(struct description): New member normal_decls_num.
	(struct automaton): New members advance_ainsn and collapse_ainsn.
	(gen_automata_option): Check for COLLAPSE_OPTION.
	(collapse_ndfa_insn_decl): New static variable.
	(add_collapse_ndfa_insn_decl, special_decl_p): New functions.
	(find_arc): If insn is the collapse-ndfa insn, accept any arc we
	find.
	(transform_insn_regexps): Call add_collapse_ndfa_insn_decl if
	necessary.  Use normal_decls_num rather than decls_num, remove
	test for special decls.
	(create_alt_states, form_ainsn_with_same_reservs): Use
	special_decl_p.
	(make_automaton); Likewise.  Use the new advance_cycle_insn member
	of struct automaton.
	(create_composed_state): Disallow advance-cycle arcs if collapse_flag
	is set.
	(NDFA_to_DFA): Don't create composed states for the collapse-ndfa
	transition.  Create the necessary transitions for it.
	(create_ainsns): Return void.  Take an automaton_t argument, and
	update its ainsn_list, advance_ainsn and collapse_ainsn members.  All
	callers changed.
	(COLLAPSE_NDFA_VALUE_NAME): New macro.
	(output_tables): Output code to define it.
	(output_internal_insn_code_evaluation): Output code to accept
	const0_rtx as collapse-ndfa transition.
	(output_default_latencies, output_print_reservation_func,
	output_print_description): Reorganize loops to use normal_decls_num
	as loop bound; remove special case for advance_cycle_insn_decl.
	(initiate_automaton_gen): Handle COLLAPSE_OPTION.
	(check_automata_insn_issues): Check for collapse_ainsn.
	(expand_automate): Allocate sufficient space.  Initialize
	normal_decls_num.

From-SVN: r178059

1 files changed, 10 insertions, 0 deletions

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 0bd9ecd..da5b799 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -7962,6 +7962,16 @@ nondeterministic treatment means trying all alternatives, some of them
 may be rejected by reservations in the subsequent insns.
 
 @item
+@dfn{collapse-ndfa} modifies the behaviour of the generator when
+producing an automaton.  An additional state transition to collapse a
+nondeterministic @acronym{NDFA} state to a deterministic @acronym{DFA}
+state is generated.  It can be triggered by passing @code{const0_rtx} to
+state_transition.  In such an automaton, cycle advance transitions are
+available only for these collapsed states.  This option is useful for
+ports that want to use the @code{ndfa} option, but also want to use
+@code{define_query_cpu_unit} to assign units to insns issued in a cycle.
+
+@item
 @dfn{progress} means output of a progress bar showing how many states
 were generated so far for automaton being processed.  This is useful
 during debugging a @acronym{DFA} description.  If you see too many