rtl-ssa: Rework _ignoring interfaces

rtl-ssa has routines for scanning forwards or backwards for something
under the control of an exclusion set.  These searches are currently
used for two main things:

- to work out where an instruction can be moved within its EBB
- to work out whether recog can add a new hard register clobber

The exclusion set was originally a callback function that returned
true for insns that should be ignored.  However, for the late-combine
work, I'd also like to be able to skip an entire definition, along
with all its uses.

This patch prepares for that by turning the exclusion set into an
object that provides predicate member functions.  Currently the
only two member functions are:

- should_ignore_insn: what the old callback did
- should_ignore_def: the new functionality

but more could be added later.

Doing this also makes it easy to remove some asymmetry that I think
in hindsight was a mistake: in forward scans, ignoring an insn meant
ignoring all definitions in that insn (ok) and all uses of those
definitions (non-obvious).  The new interface makes it possible
to select the required behaviour, with that behaviour being applied
consistently in both directions.

Now that the exclusion set is a dedicated object, rather than
just a "random" function, I think it makes sense to remove the
_ignoring suffix from the function names.  The suffix was originally
there to describe the callback, and in particular to emphasise that
a true return meant "ignore" rather than "heed".

gcc/
	* rtl-ssa.h: Include predicates.h.
	* rtl-ssa/predicates.h: New file.
	* rtl-ssa/access-utils.h (prev_call_clobbers_ignoring): Rename to...
	(prev_call_clobbers): ...this and treat the ignore parameter as an
	object with the same interface as ignore_nothing.
	(next_call_clobbers_ignoring): Rename to...
	(next_call_clobbers): ...this and treat the ignore parameter as an
	object with the same interface as ignore_nothing.
	(first_nondebug_insn_use_ignoring): Rename to...
	(first_nondebug_insn_use): ...this and treat the ignore parameter as
	an object with the same interface as ignore_nothing.
	(last_nondebug_insn_use_ignoring): Rename to...
	(last_nondebug_insn_use): ...this and treat the ignore parameter as
	an object with the same interface as ignore_nothing.
	(last_access_ignoring): Rename to...
	(last_access): ...this and treat the ignore parameter as an object
	with the same interface as ignore_nothing.  Conditionally skip
	definitions.
	(prev_access_ignoring): Rename to...
	(prev_access): ...this and treat the ignore parameter as an object
	with the same interface as ignore_nothing.
	(first_def_ignoring): Replace with...
	(first_access): ...this new function.
	(next_access_ignoring): Rename to...
	(next_access): ...this and treat the ignore parameter as an object
	with the same interface as ignore_nothing.  Conditionally skip
	definitions.
	* rtl-ssa/change-utils.h (insn_is_changing): Delete.
	(restrict_movement_ignoring): Rename to...
	(restrict_movement): ...this and treat the ignore parameter as an
	object with the same interface as ignore_nothing.
	(recog_ignoring): Rename to...
	(recog): ...this and treat the ignore parameter as an object with
	the same interface as ignore_nothing.
	* rtl-ssa/changes.h (insn_is_changing_closure): Delete.
	* rtl-ssa/functions.h (function_info::add_regno_clobber): Treat
	the ignore parameter as an object with the same interface as
	ignore_nothing.
	* rtl-ssa/insn-utils.h (insn_is): Delete.
	* rtl-ssa/insns.h (insn_is_closure): Delete.
	* rtl-ssa/member-fns.inl
	(insn_is_changing_closure::insn_is_changing_closure): Delete.
	(insn_is_changing_closure::operator()): Likewise.
	(function_info::add_regno_clobber): Treat the ignore parameter
	as an object with the same interface as ignore_nothing.
	(ignore_changing_insns::ignore_changing_insns): New function.
	(ignore_changing_insns::should_ignore_insn): Likewise.
	* rtl-ssa/movement.h (restrict_movement_for_dead_range): Treat
	the ignore parameter as an object with the same interface as
	ignore_nothing.
	(restrict_movement_for_defs_ignoring): Rename to...
	(restrict_movement_for_defs): ...this and treat the ignore parameter
	as an object with the same interface as ignore_nothing.
	(restrict_movement_for_uses_ignoring): Rename to...
	(restrict_movement_for_uses): ...this and treat the ignore parameter
	as an object with the same interface as ignore_nothing.  Conditionally
	skip definitions.
	* doc/rtl.texi: Update for above name changes.  Use
	ignore_changing_insns instead of insn_is_changing.
	* config/aarch64/aarch64-cc-fusion.cc (cc_fusion::parallelize_insns):
	Likewise.
	* pair-fusion.cc (no_ignore): Delete.
	(latest_hazard_before, first_hazard_after): Update for above name
	changes.  Use ignore_nothing instead of no_ignore.
	(pair_fusion_bb_info::fuse_pair): Update for above name changes.
	Use ignore_changing_insns instead of insn_is_changing.
	(pair_fusion::try_promote_writeback): Likewise.

Author: rsandifo-arm

gcc/config/aarch64/aarch64-cc-fusion.cc

@@ -183,7 +183,7 @@ cc_fusion::parallelize_insns (def_info *cc_def, rtx cc_set,
   auto other_change = insn_change::delete_insn (other_insn);
   insn_change *changes[] = { &other_change, &cc_change };
   cc_change.move_range = cc_insn->ebb ()->insn_range ();
-  if (!restrict_movement_ignoring (cc_change, insn_is_changing (changes)))
+  if (!restrict_movement (cc_change, ignore_changing_insns (changes)))
     {
       if (dump_file && (dump_flags & TDF_DETAILS))
 	fprintf (dump_file, "-- cannot satisfy all definitions and uses\n");
@@ -205,7 +205,7 @@ cc_fusion::parallelize_insns (def_info *cc_def, rtx cc_set,
   validate_change (cc_rtl, &PATTERN (cc_rtl), m_parallel, 1);
 
   // These routines report failures themselves.
-  if (!recog_ignoring (attempt, cc_change, insn_is_changing (changes))
+  if (!recog (attempt, cc_change, ignore_changing_insns (changes))
       || !changes_are_worthwhile (changes)
       || !crtl->ssa->verify_insn_changes (changes))
     return false;

gcc/doc/rtl.texi

@@ -5073,7 +5073,7 @@ in the correct order with respect to each other.
 The way to do this is:
 
 @smallexample
-if (!rtl_ssa::restrict_movement_ignoring (change, insn_is_changing (changes)))
+if (!rtl_ssa::restrict_movement (change, ignore_changing_insns (changes)))
   return false;
 @end smallexample
 
@@ -5085,7 +5085,7 @@ changing instructions (which might, for example, no longer need
 to clobber the flags register).  The way to do this is:
 
 @smallexample
-if (!rtl_ssa::recog_ignoring (attempt, change, insn_is_changing (changes)))
+if (!rtl_ssa::recog (attempt, change, ignore_changing_insns (changes)))
   return false;
 @end smallexample
 
@@ -5137,16 +5137,16 @@ change2.move_range = @dots{};
 
 rtl_ssa::insn_change *changes[] = @{ &change1, &change2 @};
 
-auto is_changing = insn_is_changing (changes);
-if (!rtl_ssa::restrict_movement_ignoring (change1, is_changing)
-    || !rtl_ssa::restrict_movement_ignoring (change2, is_changing))
+auto ignore = ignore_changing_insns (changes);
+if (!rtl_ssa::restrict_movement (change1, ignore)
+    || !rtl_ssa::restrict_movement (change2, ignore))
   return false;
 
 insn_change_watermark watermark;
 // Use validate_change etc. to change INSN1's and INSN2's patterns.
 @dots{}
-if (!rtl_ssa::recog_ignoring (attempt, change1, is_changing)
-    || !rtl_ssa::recog_ignoring (attempt, change2, is_changing)
+if (!rtl_ssa::recog (attempt, change1, ignore)
+    || !rtl_ssa::recog (attempt, change2, ignore)
     || !rtl_ssa::changes_are_worthwhile (changes)
     || !crtl->ssa->verify_insn_changes (changes))
   return false;

gcc/pair-fusion.cc

@@ -563,9 +563,6 @@ pair_fusion_bb_info::track_access (insn_info *insn, bool load_p, rtx mem)
     }
 }
 
-// Dummy predicate that never ignores any insns.
-static bool no_ignore (insn_info *) { return false; }
-
 // Return the latest dataflow hazard before INSN.
 //
 // If IGNORE is non-NULL, this points to a sub-rtx which we should ignore for
@@ -643,9 +640,8 @@ latest_hazard_before (insn_info *insn, rtx *ignore,
 	  if (!call_group->clobbers (def->resource ()))
 	    continue;
 
-	  auto clobber_insn = prev_call_clobbers_ignoring (*call_group,
-							   def->insn (),
-							   no_ignore);
+	  auto clobber_insn = prev_call_clobbers (*call_group, def->insn (),
+						  ignore_nothing ());
 	  if (clobber_insn)
 	    hazard (clobber_insn);
 	}
@@ -704,9 +700,8 @@ first_hazard_after (insn_info *insn, rtx *ignore)
 	  if (!call_group->clobbers (def->resource ()))
 	    continue;
 
-	  auto clobber_insn = next_call_clobbers_ignoring (*call_group,
-							   def->insn (),
-							   no_ignore);
+	  auto clobber_insn = next_call_clobbers (*call_group, def->insn (),
+						  ignore_nothing ());
 	  if (clobber_insn)
 	    hazard (clobber_insn);
 	}
@@ -733,16 +728,15 @@ first_hazard_after (insn_info *insn, rtx *ignore)
 
       // Also need to handle call clobbers of our uses (again WaR).
       //
-      // See restrict_movement_for_uses_ignoring for why we don't
-      // need to check backwards for call clobbers.
+      // See restrict_movement_for_uses for why we don't need to check
+      // backwards for call clobbers.
       for (auto call_group : use->ebb ()->call_clobbers ())
 	{
 	  if (!call_group->clobbers (use->resource ()))
 	    continue;
 
-	  auto clobber_insn = next_call_clobbers_ignoring (*call_group,
-							   use->insn (),
-							   no_ignore);
+	  auto clobber_insn = next_call_clobbers (*call_group, use->insn (),
+						  ignore_nothing ());
 	  if (clobber_insn)
 	    hazard (clobber_insn);
 	}
@@ -1965,12 +1959,12 @@ pair_fusion_bb_info::fuse_pair (bool load_p,
 	}
     }
 
-  auto is_changing = insn_is_changing (changes);
+  auto ignore = ignore_changing_insns (changes);
   for (unsigned i = 0; i < changes.length (); i++)
-    gcc_assert (rtl_ssa::restrict_movement_ignoring (*changes[i], is_changing));
+    gcc_assert (rtl_ssa::restrict_movement (*changes[i], ignore));
 
   // Check the pair pattern is recog'd.
-  if (!rtl_ssa::recog_ignoring (attempt, *pair_change, is_changing))
+  if (!rtl_ssa::recog (attempt, *pair_change, ignore))
     {
       if (dump_file)
 	fprintf (dump_file, "  failed to form pair, recog failed\n");
@@ -2953,11 +2947,11 @@ pair_fusion::try_promote_writeback (insn_info *insn, bool load_p)
 					pair_change.new_defs);
   gcc_assert (pair_change.new_defs.is_valid ());
 
-  auto is_changing = insn_is_changing (changes);
+  auto ignore = ignore_changing_insns (changes);
   for (unsigned i = 0; i < ARRAY_SIZE (changes); i++)
-    gcc_assert (rtl_ssa::restrict_movement_ignoring (*changes[i], is_changing));
+    gcc_assert (rtl_ssa::restrict_movement (*changes[i], ignore));
 
-  if (!rtl_ssa::recog_ignoring (attempt, pair_change, is_changing))
+  if (!rtl_ssa::recog (attempt, pair_change, ignore))
     {
       if (dump_file)
 	fprintf (dump_file, "i%d: recog failed on wb pair, bailing out\n",

gcc/rtl-ssa.h

@@ -63,6 +63,7 @@
 #include "rtl-ssa/blocks.h"
 #include "rtl-ssa/changes.h"
 #include "rtl-ssa/functions.h"
+#include "rtl-ssa/predicates.h"
 #include "rtl-ssa/is-a.inl"
 #include "rtl-ssa/access-utils.h"
 #include "rtl-ssa/insn-utils.h"