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, 18 insertions, 9 deletions

diff --git a/gcc/gcse.c b/gcc/gcse.c
index b6b7c5e..e3ffae0 100644
--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -4584,14 +4584,15 @@ one_pre_gcse_pass (int pass)
   return changed;
 }
 
-/* If X contains any LABEL_REF's, add REG_LABEL notes for them to INSN.
-   If notes are added to an insn which references a CODE_LABEL, the
-   LABEL_NUSES count is incremented.  We have to add REG_LABEL notes,
-   because the following loop optimization pass requires them.  */
+/* If X contains any LABEL_REF's, add REG_LABEL_OPERAND notes for them
+   to INSN.  If such notes are added to an insn which references a
+   CODE_LABEL, the LABEL_NUSES count is incremented.  We have to add
+   that note, because the following loop optimization pass requires
+   them.  */
 
 /* ??? If there was a jump optimization pass after gcse and before loop,
    then we would not need to do this here, because jump would add the
-   necessary REG_LABEL notes.  */
+   necessary REG_LABEL_OPERAND and REG_LABEL_TARGET notes.  */
 
 static void
 add_label_notes (rtx x, rtx insn)
@@ -4608,10 +4609,18 @@ add_label_notes (rtx x, rtx insn)
 	 We no longer ignore such label references (see LABEL_REF handling in
 	 mark_jump_label for additional information).  */
 
-      REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, XEXP (x, 0),
-					    REG_NOTES (insn));
-      if (LABEL_P (XEXP (x, 0)))
-	LABEL_NUSES (XEXP (x, 0))++;
+	if (reg_mentioned_p (XEXP (x, 0), insn))
+	  {
+	    /* There's no reason for current users to emit jump-insns
+	       with such a LABEL_REF, so we don't have to handle
+	       REG_LABEL_TARGET notes.  */
+	    gcc_assert (!JUMP_P (insn));
+	    REG_NOTES (insn)
+	      = gen_rtx_INSN_LIST (REG_LABEL_OPERAND, XEXP (x, 0),
+				   REG_NOTES (insn));
+	    if (LABEL_P (XEXP (x, 0)))
+	      LABEL_NUSES (XEXP (x, 0))++;
+	  }
       return;
     }