re PR debug/41535 (Broken var location info after scheduling)

PR debug/41535
* sched-deps.c (depl_on_debug_p): New.
(attach_dep_link): Reject debug deps before nondebug deps.
(add_to_deps_list): Insert debug deps after nondebug deps.
(sd_lists_empty_p): Stop at first nonempty list.  Disregard debug
deps.
(sd_add_dep): Do not reject debug deps.
(add_insn_mem_dependence): Don't count debug deps.
(remove_from_deps): Likewise.
(sched_analyze_2): Set up mem deps on debug insns.
(sched_analyze_insn): Record reg uses for deps on debug insns.
* haifa-sched.c (schedule_insn): Reset deferred debug insn.  Don't
try_ready nondebug insn after debug insn.
* ddg.c (create_ddg_dep_from_intra_loop_link,
create_ddg_dep_no_link): Don't reject debug deps.

From-SVN: r152927

4 files changed, 140 insertions, 55 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ed8d6e3..212a9e2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,21 @@
+2009-10-17  Alexandre Oliva  <aoliva@redhat.com>
+
+	PR debug/41535
+	* sched-deps.c (depl_on_debug_p): New.
+	(attach_dep_link): Reject debug deps before nondebug deps.
+	(add_to_deps_list): Insert debug deps after nondebug deps.
+	(sd_lists_empty_p): Stop at first nonempty list.  Disregard debug
+	deps.
+	(sd_add_dep): Do not reject debug deps.
+	(add_insn_mem_dependence): Don't count debug deps.
+	(remove_from_deps): Likewise.
+	(sched_analyze_2): Set up mem deps on debug insns.
+	(sched_analyze_insn): Record reg uses for deps on debug insns.
+	* haifa-sched.c (schedule_insn): Reset deferred debug insn.  Don't
+	try_ready nondebug insn after debug insn.
+	* ddg.c (create_ddg_dep_from_intra_loop_link,
+	create_ddg_dep_no_link): Don't reject debug deps.
+
 2009-10-16  Richard Guenther  <rguenther@suse.de>
 
 	* lto-symtab.c (merge_incomplete_and_complete_type): Remove.
diff --git a/gcc/ddg.c b/gcc/ddg.c
index 439acd1..c06ea75 100644
--- a/gcc/ddg.c
+++ b/gcc/ddg.c
@@ -167,7 +167,7 @@ create_ddg_dep_from_intra_loop_link (ddg_ptr g, ddg_node_ptr src_node,
     t = OUTPUT_DEP;
 
   gcc_assert (!DEBUG_INSN_P (dest_node->insn) || t == ANTI_DEP);
-  gcc_assert (!DEBUG_INSN_P (src_node->insn) || DEBUG_INSN_P (dest_node->insn));
+  gcc_assert (!DEBUG_INSN_P (src_node->insn) || t == ANTI_DEP);
 
   /* We currently choose not to create certain anti-deps edges and
      compensate for that by generating reg-moves based on the life-range
@@ -213,7 +213,7 @@ create_ddg_dep_no_link (ddg_ptr g, ddg_node_ptr from, ddg_node_ptr to,
   struct _dep _dep, *dep = &_dep;
 
   gcc_assert (!DEBUG_INSN_P (to->insn) || d_t == ANTI_DEP);
-  gcc_assert (!DEBUG_INSN_P (from->insn) || DEBUG_INSN_P (to->insn));
+  gcc_assert (!DEBUG_INSN_P (from->insn) || d_t == ANTI_DEP);
 
   if (d_t == ANTI_DEP)
     dep_kind = REG_DEP_ANTI;
diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index dc0791f..bc947fa 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -989,7 +989,7 @@ dep_list_size (rtx insn)
     {
       if (DEBUG_INSN_P (DEP_CON (dep)))
 	dbgcount++;
-      else
+      else if (!DEBUG_INSN_P (DEP_PRO (dep)))
 	nodbgcount++;
     }
 
@@ -1688,6 +1688,39 @@ schedule_insn (rtx insn)
      should have been removed from the ready list.  */
   gcc_assert (sd_lists_empty_p (insn, SD_LIST_BACK));
 
+  /* Reset debug insns invalidated by moving this insn.  */
+  if (MAY_HAVE_DEBUG_INSNS && !DEBUG_INSN_P (insn))
+    for (sd_it = sd_iterator_start (insn, SD_LIST_BACK);
+	 sd_iterator_cond (&sd_it, &dep);)
+      {
+	rtx dbg = DEP_PRO (dep);
+
+	gcc_assert (DEBUG_INSN_P (dbg));
+
+	if (sched_verbose >= 6)
+	  fprintf (sched_dump, ";;\t\tresetting: debug insn %d\n",
+		   INSN_UID (dbg));
+
+	/* ??? Rather than resetting the debug insn, we might be able
+	   to emit a debug temp before the just-scheduled insn, but
+	   this would involve checking that the expression at the
+	   point of the debug insn is equivalent to the expression
+	   before the just-scheduled insn.  They might not be: the
+	   expression in the debug insn may depend on other insns not
+	   yet scheduled that set MEMs, REGs or even other debug
+	   insns.  It's not clear that attempting to preserve debug
+	   information in these cases is worth the effort, given how
+	   uncommon these resets are and the likelihood that the debug
+	   temps introduced won't survive the schedule change.  */
+	INSN_VAR_LOCATION_LOC (dbg) = gen_rtx_UNKNOWN_VAR_LOC ();
+	df_insn_rescan (dbg);
+
+	/* We delete rather than resolve these deps, otherwise we
+	   crash in sched_free_deps(), because forward deps are
+	   expected to be released before backward deps.  */
+	sd_delete_dep (sd_it);
+      }
+
   gcc_assert (QUEUE_INDEX (insn) == QUEUE_NOWHERE);
   QUEUE_INDEX (insn) = QUEUE_SCHEDULED;
 
@@ -1712,6 +1745,12 @@ schedule_insn (rtx insn)
 	 advancing the iterator.  */
       sd_resolve_dep (sd_it);
 
+      /* Don't bother trying to mark next as ready if insn is a debug
+	 insn.  If insn is the last hard dependency, it will have
+	 already been discounted.  */
+      if (DEBUG_INSN_P (insn) && !DEBUG_INSN_P (next))
+	continue;
+
       if (!IS_SPECULATION_BRANCHY_CHECK_P (insn))
 	{
 	  int effective_cost;      
diff --git a/gcc/sched-deps.c b/gcc/sched-deps.c
index cef383a..1fd484d 100644
--- a/gcc/sched-deps.c
+++ b/gcc/sched-deps.c
@@ -211,6 +211,16 @@ sd_debug_dep (dep_t dep)
   fprintf (stderr, "\n");
 }
 
+/* Determine whether DEP is a dependency link of a non-debug insn on a
+   debug insn.  */
+
+static inline bool
+depl_on_debug_p (dep_link_t dep)
+{
+  return (DEBUG_INSN_P (DEP_LINK_PRO (dep))
+	  && !DEBUG_INSN_P (DEP_LINK_CON (dep)));
+}
+
 /* Functions to operate with a single link from the dependencies lists -
    dep_link_t.  */
 
@@ -246,7 +256,9 @@ add_to_deps_list (dep_link_t link, deps_list_t l)
 {
   attach_dep_link (link, &DEPS_LIST_FIRST (l));
 
-  ++DEPS_LIST_N_LINKS (l);
+  /* Don't count debug deps.  */
+  if (!depl_on_debug_p (link))
+    ++DEPS_LIST_N_LINKS (l);
 }
 
 /* Detach dep_link L from the list.  */
@@ -271,7 +283,9 @@ remove_from_deps_list (dep_link_t link, deps_list_t list)
 {
   detach_dep_link (link);
 
-  --DEPS_LIST_N_LINKS (list);
+  /* Don't count debug deps.  */
+  if (!depl_on_debug_p (link))
+    --DEPS_LIST_N_LINKS (list);
 }
 
 /* Move link LINK from list FROM to list TO.  */
@@ -668,10 +682,21 @@ sd_lists_size (const_rtx insn, sd_list_types_def list_types)
 }
 
 /* Return true if INSN's lists defined by LIST_TYPES are all empty.  */
+
 bool
 sd_lists_empty_p (const_rtx insn, sd_list_types_def list_types)
 {
-  return sd_lists_size (insn, list_types) == 0;
+  while (list_types != SD_LIST_NONE)
+    {
+      deps_list_t list;
+      bool resolved_p;
+
+      sd_next_list (insn, &list_types, &list, &resolved_p);
+      if (!deps_list_empty_p (list))
+	return false;
+    }
+
+  return true;
 }
 
 /* Initialize data for INSN.  */
@@ -1201,7 +1226,6 @@ sd_add_dep (dep_t dep, bool resolved_p)
   rtx insn = DEP_CON (dep);
 
   gcc_assert (INSN_P (insn) && INSN_P (elem) && insn != elem);
-  gcc_assert (!DEBUG_INSN_P (elem) || DEBUG_INSN_P (insn));
 
   if ((current_sched_info->flags & DO_SPECULATION)
       && !sched_insn_is_legitimate_for_speculation_p (insn, DEP_STATUS (dep)))
@@ -1528,7 +1552,8 @@ add_insn_mem_dependence (struct deps *deps, bool read_p,
     {
       insn_list = &deps->pending_read_insns;
       mem_list = &deps->pending_read_mems;
-      deps->pending_read_list_length++;
+      if (!DEBUG_INSN_P (insn))
+	deps->pending_read_list_length++;
     }
   else
     {
@@ -2408,63 +2433,63 @@ sched_analyze_2 (struct deps *deps, rtx x, rtx insn)
 	rtx pending, pending_mem;
 	rtx t = x;
 
-	if (DEBUG_INSN_P (insn))
-	  {
-	    sched_analyze_2 (deps, XEXP (x, 0), insn);
-	    return;
-	  }
-
 	if (sched_deps_info->use_cselib)
 	  {
 	    t = shallow_copy_rtx (t);
 	    cselib_lookup (XEXP (t, 0), Pmode, 1);
 	    XEXP (t, 0) = cselib_subst_to_values (XEXP (t, 0));
 	  }
-	t = canon_rtx (t);
-	pending = deps->pending_read_insns;
-	pending_mem = deps->pending_read_mems;
-	while (pending)
-	  {
-	    if (read_dependence (XEXP (pending_mem, 0), t)
-		&& ! sched_insns_conditions_mutex_p (insn, XEXP (pending, 0)))
-	      note_mem_dep (t, XEXP (pending_mem, 0), XEXP (pending, 0),
-			    DEP_ANTI);
-
-	    pending = XEXP (pending, 1);
-	    pending_mem = XEXP (pending_mem, 1);
-	  }
 
-	pending = deps->pending_write_insns;
-	pending_mem = deps->pending_write_mems;
-	while (pending)
+	if (!DEBUG_INSN_P (insn))
 	  {
-	    if (true_dependence (XEXP (pending_mem, 0), VOIDmode,
-				 t, rtx_varies_p)
-		&& ! sched_insns_conditions_mutex_p (insn, XEXP (pending, 0)))
-	      note_mem_dep (t, XEXP (pending_mem, 0), XEXP (pending, 0),
-			    sched_deps_info->generate_spec_deps
-			    ? BEGIN_DATA | DEP_TRUE : DEP_TRUE);
-
-	    pending = XEXP (pending, 1);
-	    pending_mem = XEXP (pending_mem, 1);
-	  }
+	    t = canon_rtx (t);
+	    pending = deps->pending_read_insns;
+	    pending_mem = deps->pending_read_mems;
+	    while (pending)
+	      {
+		if (read_dependence (XEXP (pending_mem, 0), t)
+		    && ! sched_insns_conditions_mutex_p (insn,
+							 XEXP (pending, 0)))
+		  note_mem_dep (t, XEXP (pending_mem, 0), XEXP (pending, 0),
+				DEP_ANTI);
+
+		pending = XEXP (pending, 1);
+		pending_mem = XEXP (pending_mem, 1);
+	      }
 
-	for (u = deps->last_pending_memory_flush; u; u = XEXP (u, 1))
-	  {
-	    if (! JUMP_P (XEXP (u, 0)))
-	      add_dependence (insn, XEXP (u, 0), REG_DEP_ANTI);
-	    else if (deps_may_trap_p (x))
+	    pending = deps->pending_write_insns;
+	    pending_mem = deps->pending_write_mems;
+	    while (pending)
 	      {
-		if ((sched_deps_info->generate_spec_deps)
-		    && sel_sched_p () && (spec_info->mask & BEGIN_CONTROL))
-		  {
-		    ds_t ds = set_dep_weak (DEP_ANTI, BEGIN_CONTROL,
-					    MAX_DEP_WEAK);
+		if (true_dependence (XEXP (pending_mem, 0), VOIDmode,
+				     t, rtx_varies_p)
+		    && ! sched_insns_conditions_mutex_p (insn,
+							 XEXP (pending, 0)))
+		  note_mem_dep (t, XEXP (pending_mem, 0), XEXP (pending, 0),
+				sched_deps_info->generate_spec_deps
+				? BEGIN_DATA | DEP_TRUE : DEP_TRUE);
+
+		pending = XEXP (pending, 1);
+		pending_mem = XEXP (pending_mem, 1);
+	      }
 
-		    note_dep (XEXP (u, 0), ds);
-		  }
-		else
+	    for (u = deps->last_pending_memory_flush; u; u = XEXP (u, 1))
+	      {
+		if (! JUMP_P (XEXP (u, 0)))
 		  add_dependence (insn, XEXP (u, 0), REG_DEP_ANTI);
+		else if (deps_may_trap_p (x))
+		  {
+		    if ((sched_deps_info->generate_spec_deps)
+			&& sel_sched_p () && (spec_info->mask & BEGIN_CONTROL))
+		      {
+			ds_t ds = set_dep_weak (DEP_ANTI, BEGIN_CONTROL,
+						MAX_DEP_WEAK);
+
+			note_dep (XEXP (u, 0), ds);
+		      }
+		    else
+		      add_dependence (insn, XEXP (u, 0), REG_DEP_ANTI);
+		  }
 	      }
 	  }
 
@@ -2473,7 +2498,6 @@ sched_analyze_2 (struct deps *deps, rtx x, rtx insn)
         if (!deps->readonly)
           add_insn_mem_dependence (deps, true, insn, x);
 
-	/* Take advantage of tail recursion here.  */
 	sched_analyze_2 (deps, XEXP (x, 0), insn);
 
 	if (cslr_p && sched_deps_info->finish_rhs)
@@ -2773,6 +2797,9 @@ sched_analyze_insn (struct deps *deps, rtx x, rtx insn)
 	  struct deps_reg *reg_last = &deps->reg_last[i];
 	  add_dependence_list (insn, reg_last->sets, 1, REG_DEP_ANTI);
 	  add_dependence_list (insn, reg_last->clobbers, 1, REG_DEP_ANTI);
+
+	  if (!deps->readonly)
+	    reg_last->uses = alloc_INSN_LIST (insn, reg_last->uses);
 	}
       CLEAR_REG_SET (reg_pending_uses);
 
@@ -3505,7 +3532,8 @@ remove_from_deps (struct deps *deps, rtx insn)
   
   removed = remove_from_both_dependence_lists (insn, &deps->pending_read_insns,
                                                &deps->pending_read_mems);
-  deps->pending_read_list_length -= removed;
+  if (!DEBUG_INSN_P (insn))
+    deps->pending_read_list_length -= removed;
   removed = remove_from_both_dependence_lists (insn, &deps->pending_write_insns,
                                                &deps->pending_write_mems);
   deps->pending_write_list_length -= removed;