Divide REG_LABEL notes into REG_LABEL_OPERAND and REG_LABEL_TARGET.

	* doc/rtl.texi (Insns): Specify when a label_ref makes a jump_insn.
	Similar for what label_refs can go in the JUMP_TARGET field.  Split
	REG_LABEL documentation into REG_LABEL_TARGET and REG_LABEL_OPERAND.
	* reload.c (find_reloads): Generate REG_LABEL_OPERAND, not
	REG_LABEL when replacing an operand with a LABEL_REF for a
	non-jump insn.
	(subst_reloads): When replacing a LABEL_REG with a register,
	instead of generating a REG_LABEL note, assert that there already
	is one or that the label is a known target for the insn.
	* rtlanal.c (computed_jump_p): Instead of looking for a REG_LABEL
	note, check the JUMP_LABEL field.  Remove "else" after return.
	* reorg.c (emit_delay_sequence): Replace case for REG_LABEL with
	cases for REG_LABEL_OPERAND and REG_LABEL_TARGET.
	(fill_slots_from_thread): Handle both REG_LABEL_OPERAND and
	REG_LABEL_TARGET notes, including the JUMP_TARGET field on JUMP_P
	insns.  Iterate over all notes; don't assume there's only one.
	* cse.c (recorded_label_ref): Adjust comment to refer to
	REG_LABEL_OPERAND.
	(cse_extended_basic_block): Do LABEL_REF check for all INSN_P
	insns, not just NONJUMP_INSN_P.
	(check_for_label_ref): For JUMP_P insns, check that the LABEL_REF
	isn't a jump target.
	* jump.c (rebuild_jump_labels): Adjust head comment.
	(init_label_info): Ditto.  Remove REG_LABEL_OPERAND notes only;
	don't reset REG_LABEL_TARGET notes, including the JUMP_LABEL field.
	(mark_all_labels): For JUMP_P insns without a target, check if the
	the target is noted on the previous nonjump insn.
	(mark_jump_label_1): New function, guts from mark_jump_label.
	<case IF_THEN_ELSE>: Handle first operand as a non-target when
	marking jump target labels.
	<case LABEL_REF>: Adjust for whether to generate a
	REG_LABEL_TARGET or a REG_LABEL_OPERAND note.
	For 'E' format rtl, iterate in descending element order.
	(delete_related_insns): Handle both REG_LABEL_TARGET and
	REG_LABEL_OPERAND notes.  For JUMP_P insns with labels with zero
	reference count, delete and fallthrough.  Move finding-next-
	non-deleted insn last in the function.  Look at all INSN_P insns
	for REG_LABEL_OPERAND notes.
	(redirect_jump_2): Assert that OLABEL equals the old JUMP_LABEL of
	JUMP.
	* print-rtl.c (print_rtx): For JUMP_P insns and a non-NULL
	JUMP_LABEL, output the INSN_UID of it.
	* gcse.c: Adjust comments as appropriate to say REG_LABEL_OPERAND
	and/or REG_LABEL_TARGET.
	(add_label_notes): Only add REG_LABEL_OPERAND notes.  Put in line
	with jump.c copy by only adding notes for labels actually
	referenced in the insn.
	* emit-rtl.c (try_split): Don't assume only NONJUMP_INSN_P need
	usage count increment; handle all INSN_P trial insns.
	(emit_copy_of_insn_after): Change to not copy REG_LABEL_OPERAND
	notes.
	* rtl.h (struct rtx_def) <volatil>: Adjust to mention
	REG_LABEL_TARGET and REG_LABEL_OPERAND.
	(LABEL_REF_NONLOCAL_P): Allow REG_LABEL_TARGET and
	REG_LABEL_OPERAND.
	* combine.c (distribute_notes): Adjust for REG_LABEL_TARGET on
	JUMP_P insns and REG_LABEL_OPERAND everywhere.
	* sched-rgn.c (is_cfg_nonregular): Check for REG_LABEL_OPERANDS
	on all INSN_P insns.
	* reg-notes.def (LABEL_TARGET, LABEL_OPERAND): Split from LABEL.
	* cfgrtl.c (delete_insn): Adjust to handle REG_LABEL_TARGET and
	REG_LABEL_OPERAND notes.
	* reload1.c (calculate_needs_all_insns): Adjust comments.
	(set_label_offsets): Adjust to look for REG_LABEL_OPERAND notes.
	* config/alpha/alpha.md (split for load of an address into a
	four-insn sequence on Unicos/Mk): Adjust to use
	REG_LABEL_OPERAND.
	* config/sh/sh.md (sh_reorg, final_prescan_insn): Ditto.

From-SVN: r128287

1 files changed, 27 insertions, 13 deletions

diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi
index 83fa089..639aabe 100644
--- a/gcc/doc/rtl.texi
+++ b/gcc/doc/rtl.texi
@@ -3201,9 +3201,10 @@ mandatory ones listed above.  These four are described in a table below.
 @findex jump_insn
 @item jump_insn
 The expression code @code{jump_insn} is used for instructions that may
-jump (or, more generally, may contain @code{label_ref} expressions).  If
-there is an instruction to return from the current function, it is
-recorded as a @code{jump_insn}.
+jump (or, more generally, may contain @code{label_ref} expressions to
+which @code{pc} can be set in that instruction).  If there is an
+instruction to return from the current function, it is recorded as a
+@code{jump_insn}.
 
 @findex JUMP_LABEL
 @code{jump_insn} insns have the same extra fields as @code{insn} insns,
@@ -3213,9 +3214,11 @@ accessed in the same way and in addition contain a field
 For simple conditional and unconditional jumps, this field contains
 the @code{code_label} to which this insn will (possibly conditionally)
 branch.  In a more complex jump, @code{JUMP_LABEL} records one of the
-labels that the insn refers to; the only way to find the others is to
-scan the entire body of the insn.  In an @code{addr_vec},
-@code{JUMP_LABEL} is @code{NULL_RTX}.
+labels that the insn refers to; other jump target labels are recorded
+as @code{REG_LABEL_TARGET} notes.  The exception is @code{addr_vec}
+and @code{addr_diff_vec}, where @code{JUMP_LABEL} is @code{NULL_RTX}
+and the only way to find the labels is to scan the entire body of the
+insn.
 
 Return insns count as jumps, but since they do not refer to any
 labels, their @code{JUMP_LABEL} is @code{NULL_RTX}.
@@ -3531,14 +3534,25 @@ note giving the expression being computed.  This block is encapsulated
 with @code{REG_LIBCALL} and @code{REG_RETVAL} notes on the first and
 last insns, respectively.
 
-@findex REG_LABEL
-@item REG_LABEL
+@findex REG_LABEL_OPERAND
+@item REG_LABEL_OPERAND
 This insn uses @var{op}, a @code{code_label} or a @code{note} of type
-@code{NOTE_INSN_DELETED_LABEL}, but is not a
-@code{jump_insn}, or it is a @code{jump_insn} that required the label to
-be held in a register.  The presence of this note allows jump
-optimization to be aware that @var{op} is, in fact, being used, and flow
-optimization to build an accurate flow graph.
+@code{NOTE_INSN_DELETED_LABEL}, but is not a @code{jump_insn}, or it
+is a @code{jump_insn} that refers to the operand as an ordinary
+operand.  The label may still eventually be a jump target, but if so
+in an indirect jump in a subsequent insn.  The presence of this note
+allows jump optimization to be aware that @var{op} is, in fact, being
+used, and flow optimization to build an accurate flow graph.
+
+@findex REG_LABEL_TARGET
+@item REG_LABEL_TARGET
+This insn is a @code{jump_insn} but not a @code{addr_vec} or
+@code{addr_diff_vec}.  It uses @var{op}, a @code{code_label} as a
+direct or indirect jump target.  Its purpose is similar to that of
+@code{REG_LABEL_OPERAND}.  This note is only present if the insn has
+multiple targets; the last label in the insn (in the highest numbered
+insn-field) goes into the @code{JUMP_LABEL} field and does not have a
+@code{REG_LABEL_TARGET} note.  @xref{Insns, JUMP_LABEL}.
 
 @findex REG_CROSSING_JUMP
 @item REG_CROSSING_JUMP