ddg.c (build_intra_loop_deps): Adjust add_forward_dependence call.

2006-03-16  Maxim Kuvyrkov <mkuvyrkov@ispras.ru>
            Andrey Belevantsev <abel@ispras.ru>

	* ddg.c (build_intra_loop_deps): Adjust add_forward_dependence call.
        * lists.c (unused_deps_list): New variable.
	(free_list): Add assertions to verify the proper distinguishing 
        between INSN_LISTs and DEPS_LISTs.
        (find_list_elem, remove_list_elem, remove_list_node): New static
	functions.
        (alloc_DEPS_LIST, free_DEPS_LIST, free_DEPS_LIST_node,
        remove_free_INSN_LIST_elem, remove_free_DEPS_LIST_elem,
        remove_free_INSN_LIST_node, remove_free_DEPS_LIST_node): New functions.
        (alloc_INSN_LIST): Assert that the list we're working on is indeed
	an INSN_LIST.
        (free_INSN_LIST_node): Likewise.
	* modulo-sched.c (current_sched_info): Initialize flags field.
	* reg-notes.def: Exchange DEP_ANTI and DEP_OUTPUT.
	* rtl.def (DEPS_LIST): Define.
        * rtl.h: Declare new functions from lists.c.
        * sched-deps.c (spec_dependency_cache): New static variable.
        (maybe_add_or_update_back_dep_1, add_back_dep): New static functions.
        (add_dependence): Change return type to void.  Move the logic to ...
        (add_or_update_back_dep_1): ... here.  Handle speculative dependencies.
        (delete_all_dependences): Add comment about forward_dependency_cache.
	Handle spec_dependency_cache.  Handle DEPS_LISTs.
        (fixup_sched_groups): Clarify the change of priority of output
        and anti dependencies.
        (sched_analyze_2): Adjust add_dependence calls to create data
	speculative dependence.
        (add_forward_dependence): Renamed to add_forw_dep, change prototype.
	Adjust all callers.  Handle DEPS_LISTS.
        (compute_forward_dependences): Use add_forw_dep.  Sort LOG_LINKs in
	presence of speculation.
        (init_dependency_caches, free_dependency_caches):
	Handle spec_dependency_cache.
        (adjust_add_sorted_back_dep, adjust_back_add_forw_dep, delete_forw_dep,
	estimate_dep_weak, get_dep_weak, ds_merge, check_dep_status):
	New static functions.
        (add_or_update_back_dep, add_or_update_back_forw_dep,
	add_back_forw_dep, delete_back_forw_dep): New functions.
	* sched-int.h (ds_t, dw_t): New typedefs.
	(struct sched_info): Add new field flags.
	(struct haifa_insn_data): Add new bitfield has_internal_dep.
	Prototype new sched-deps.c functions.
        (HAS_INTERNAL_DEP, DEP_STATUS): New access macros.
	(BITS_PER_DEP_STATUS, BITS_PER_DEP_WEAK, DEP_WEAK_MASK, MAX_DEP_WEAK,
	MIN_DEP_WEAK, NO_DEP_WEAK, UNCERTAIN_DEP_WEAK, BEGIN_DATA, BE_IN_DATA,
	BEGIN_CONTROL, BE_IN_CONTROL, BEGIN_SPEC, DATA_SPEC, CONTROL_SPEC,
	SPECULATIVE, BE_IN_SPEC, FIRST_SPEC_TYPE, LAST_SPEC_TYPE,
	SPEC_TYPE_SHIFT, DEP_TRUE, DEP_OUTPUT, DEP_ANTI, DEP_TYPES, HARD_DEP):
	New constants.
        (enum SPEC_TYPES_OFFSETS, enum DEPS_ADJUST_RESULT, enum SCHED_FLAGS):
	New enums.
	* sched-rgn.c (current_sched_info): Initialize flags field.
	(schedule_insns): Initialize current_sched_info before the sched_init
	call.
	* sched-ebb.c (current_sched_info): Initialize flags field.
	(add_deps_for_risky_insns): Use control_flow_insn_p instead of JUMP_P.
	Call add_or_update_back_dep instead of add_dependence.
	Create control speculative dependencies.
	(schedule_insns): Initialize current_sched_info before the sched_init
	call.

Co-Authored-By: Andrey Belevantsev <abel@ispras.ru>

From-SVN: r112125

gcc/ChangeLog

+2006-03-16  Maxim Kuvyrkov <mkuvyrkov@ispras.ru>
+            Andrey Belevantsev <abel@ispras.ru>
+
+	* ddg.c (build_intra_loop_deps): Adjust add_forward_dependence call.
+        * lists.c (unused_deps_list): New variable.
+	(free_list): Add assertions to verify the proper distinguishing 
+        between INSN_LISTs and DEPS_LISTs.
+        (find_list_elem, remove_list_elem, remove_list_node): New static
+	functions.
+        (alloc_DEPS_LIST, free_DEPS_LIST, free_DEPS_LIST_node,
+        remove_free_INSN_LIST_elem, remove_free_DEPS_LIST_elem,
+        remove_free_INSN_LIST_node, remove_free_DEPS_LIST_node): New functions.
+        (alloc_INSN_LIST): Assert that the list we're working on is indeed
+	an INSN_LIST.
+        (free_INSN_LIST_node): Likewise.
+	* modulo-sched.c (current_sched_info): Initialize flags field.
+	* reg-notes.def: Exchange DEP_ANTI and DEP_OUTPUT.
+	* rtl.def (DEPS_LIST): Define.
+        * rtl.h: Declare new functions from lists.c.
+        * sched-deps.c (spec_dependency_cache): New static variable.
+        (maybe_add_or_update_back_dep_1, add_back_dep): New static functions.
+        (add_dependence): Change return type to void.  Move the logic to ...
+        (add_or_update_back_dep_1): ... here.  Handle speculative dependencies.
+        (delete_all_dependences): Add comment about forward_dependency_cache.
+	Handle spec_dependency_cache.  Handle DEPS_LISTs.
+        (fixup_sched_groups): Clarify the change of priority of output
+        and anti dependencies.
+        (sched_analyze_2): Adjust add_dependence calls to create data
+	speculative dependence.
+        (add_forward_dependence): Renamed to add_forw_dep, change prototype.
+	Adjust all callers.  Handle DEPS_LISTS.
+        (compute_forward_dependences): Use add_forw_dep.  Sort LOG_LINKs in
+	presence of speculation.
+        (init_dependency_caches, free_dependency_caches):
+	Handle spec_dependency_cache.
+        (adjust_add_sorted_back_dep, adjust_back_add_forw_dep, delete_forw_dep,
+	estimate_dep_weak, get_dep_weak, ds_merge, check_dep_status):
+	New static functions.
+        (add_or_update_back_dep, add_or_update_back_forw_dep,
+	add_back_forw_dep, delete_back_forw_dep): New functions.
+	* sched-int.h (ds_t, dw_t): New typedefs.
+	(struct sched_info): Add new field flags.
+	(struct haifa_insn_data): Add new bitfield has_internal_dep.
+	Prototype new sched-deps.c functions.
+        (HAS_INTERNAL_DEP, DEP_STATUS): New access macros.
+	(BITS_PER_DEP_STATUS, BITS_PER_DEP_WEAK, DEP_WEAK_MASK, MAX_DEP_WEAK,
+	MIN_DEP_WEAK, NO_DEP_WEAK, UNCERTAIN_DEP_WEAK, BEGIN_DATA, BE_IN_DATA,
+	BEGIN_CONTROL, BE_IN_CONTROL, BEGIN_SPEC, DATA_SPEC, CONTROL_SPEC,
+	SPECULATIVE, BE_IN_SPEC, FIRST_SPEC_TYPE, LAST_SPEC_TYPE,
+	SPEC_TYPE_SHIFT, DEP_TRUE, DEP_OUTPUT, DEP_ANTI, DEP_TYPES, HARD_DEP):
+	New constants.
+        (enum SPEC_TYPES_OFFSETS, enum DEPS_ADJUST_RESULT, enum SCHED_FLAGS):
+	New enums.
+	* sched-rgn.c (current_sched_info): Initialize flags field.
+	(schedule_insns): Initialize current_sched_info before the sched_init
+	call.
+	* sched-ebb.c (current_sched_info): Initialize flags field.
+	(add_deps_for_risky_insns): Use control_flow_insn_p instead of JUMP_P.
+	Call add_or_update_back_dep instead of add_dependence.
+	Create control speculative dependencies.
+	(schedule_insns): Initialize current_sched_info before the sched_init
+	call.
+
 2006-03-16  Kaz Kojima  <kkojima@gcc.gnu.org>
 
 	* config/sh/linux-unwind.h (shmedia_fallback_frame_state): Set

gcc/ddg.c

@@ -401,8 +401,7 @@ build_intra_loop_deps (ddg_ptr g)
 	  if (!src_node)
 	    continue;
 
-      	  add_forward_dependence (XEXP (link, 0), dest_node->insn,
-				  REG_NOTE_KIND (link));
+      	  add_forw_dep (dest_node->insn, link);
 	  create_ddg_dependence (g, src_node, dest_node,
 				 INSN_DEPEND (src_node->insn));
 	}

gcc/lists.c

@@ -28,6 +28,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 #include "ggc.h"
 
 static void free_list (rtx *, rtx *);
+static void free_DEPS_LIST_node (rtx);
 
 /* Functions for maintaining cache-able lists of EXPR_LIST and INSN_LISTs.  */
 
@@ -37,11 +38,14 @@ static GTY ((deletable)) rtx unused_insn_list;
 /* An EXPR_LIST containing all EXPR_LISTs allocated but currently unused.  */
 static GTY ((deletable)) rtx unused_expr_list;
 
+/* An DEPS_LIST containing all DEPS_LISTs allocated but currently unused.  */
+static GTY ((deletable)) rtx unused_deps_list;
 
-/* This function will free an entire list of either EXPR_LIST or INSN_LIST
-   nodes. This is to be used only on lists that consist exclusively of
-   nodes of one type only.  This is only called by free_EXPR_LIST_list
-   and free_INSN_LIST_list.  */
+
+/* This function will free an entire list of either EXPR_LIST, INSN_LIST
+   or DEPS_LIST nodes.  This is to be used only on lists that consist
+   exclusively of nodes of one type only.  This is only called by
+   free_EXPR_LIST_list, free_INSN_LIST_list and free_DEPS_LIST_list.  */
 static void
 free_list (rtx *listp, rtx *unused_listp)
 {
@@ -50,8 +54,18 @@ free_list (rtx *listp, rtx *unused_listp)
   prev_link = *listp;
   link = XEXP (prev_link, 1);
 
+  gcc_assert ((unused_listp != &unused_insn_list
+	       || GET_CODE (prev_link) == INSN_LIST)
+	      && (unused_listp != &unused_deps_list
+		  || GET_CODE (prev_link) == DEPS_LIST));
+  
   while (link)
     {
+      gcc_assert ((unused_listp != &unused_insn_list
+		   || GET_CODE (prev_link) == INSN_LIST)
+		  && (unused_listp != &unused_deps_list
+		      || GET_CODE (prev_link) == DEPS_LIST));
+  
       prev_link = link;
       link = XEXP (link, 1);
     }
@@ -61,6 +75,40 @@ free_list (rtx *listp, rtx *unused_listp)
   *listp = 0;
 }
 
+/* Find corresponding to ELEM node in the list pointed to by LISTP.
+   This node must exist in the list.  Returns pointer to that node.  */
+static rtx *
+find_list_elem (rtx elem, rtx *listp)
+{
+  while (XEXP (*listp, 0) != elem)
+    listp = &XEXP (*listp, 1);
+  return listp;
+}
+
+/* Remove the node pointed to by LISTP from the list.  */
+static void
+remove_list_node (rtx *listp)
+{
+  rtx node;
+
+  node = *listp;
+  *listp = XEXP (node, 1);
+  XEXP (node, 1) = 0;
+}
+
+/* Removes corresponding to ELEM node from the list pointed to by LISTP.
+   Returns that node.  */
+static rtx
+remove_list_elem (rtx elem, rtx *listp)
+{
+  rtx node;
+
+  listp = find_list_elem (elem, listp);
+  node = *listp;
+  remove_list_node (listp);
+  return node;
+}
+
 /* This call is used in place of a gen_rtx_INSN_LIST. If there is a cached
    node available, we'll use it, otherwise a call to gen_rtx_INSN_LIST
    is made.  */
@@ -76,6 +124,8 @@ alloc_INSN_LIST (rtx val, rtx next)
       XEXP (r, 0) = val;
       XEXP (r, 1) = next;
       PUT_REG_NOTE_KIND (r, VOIDmode);
+
+      gcc_assert (GET_CODE (r) == INSN_LIST);
     }
   else
     r = gen_rtx_INSN_LIST (VOIDmode, val, next);
@@ -105,6 +155,31 @@ alloc_EXPR_LIST (int kind, rtx val, rtx next)
   return r;
 }
 
+/* This call is used in place of a gen_rtx_DEPS_LIST.  If there is a cached
+   node available, we'll use it, otherwise a call to gen_rtx_DEPS_LIST
+   is made.  */
+rtx
+alloc_DEPS_LIST (rtx val, rtx next, HOST_WIDE_INT ds)
+{
+  rtx r;
+
+  if (unused_deps_list)
+    {
+      r = unused_deps_list;
+      unused_deps_list = XEXP (r, 1);
+      XEXP (r, 0) = val;
+      XEXP (r, 1) = next;
+      XWINT (r, 2) = ds;
+      PUT_REG_NOTE_KIND (r, VOIDmode);
+
+      gcc_assert (GET_CODE (r) == DEPS_LIST);
+    }
+  else
+    r = gen_rtx_DEPS_LIST (VOIDmode, val, next, ds);
+
+  return r;
+}
+
 /* This function will free up an entire list of EXPR_LIST nodes.  */
 void
 free_EXPR_LIST_list (rtx *listp)
@@ -123,6 +198,15 @@ free_INSN_LIST_list (rtx *listp)
   free_list (listp, &unused_insn_list);
 }
 
+/* This function will free up an entire list of DEPS_LIST nodes.  */
+void
+free_DEPS_LIST_list (rtx *listp)
+{
+  if (*listp == 0)
+    return;
+  free_list (listp, &unused_deps_list);
+}
+
 /* This function will free up an individual EXPR_LIST node.  */
 void
 free_EXPR_LIST_node (rtx ptr)
@@ -135,8 +219,26 @@ free_EXPR_LIST_node (rtx ptr)
 void
 free_INSN_LIST_node (rtx ptr)
 {
+  gcc_assert (GET_CODE (ptr) == INSN_LIST);
   XEXP (ptr, 1) = unused_insn_list;
   unused_insn_list = ptr;
 }
 
+/* This function will free up an individual DEPS_LIST node.  */
+static void
+free_DEPS_LIST_node (rtx ptr)
+{
+  gcc_assert (GET_CODE (ptr) == DEPS_LIST);
+  XEXP (ptr, 1) = unused_deps_list;
+  unused_deps_list = ptr;
+}
+
+/* Remove and free corresponding to ELEM node in the DEPS_LIST pointed to
+   by LISTP.  */
+void
+remove_free_DEPS_LIST_elem (rtx elem, rtx *listp)
+{
+  free_DEPS_LIST_node (remove_list_elem (elem, listp));
+}
+
 #include "gt-lists.h"

gcc/modulo-sched.c

@@ -263,7 +263,9 @@ static struct sched_info sms_sched_info =
   compute_jump_reg_dependencies,
   NULL, NULL,
   NULL, NULL,
-  0, 0, 0
+  0, 0, 0,
+
+  0
 };
 
 

gcc/reg-notes.def

@@ -99,8 +99,8 @@ REG_NOTE (LABEL)
 
 /* REG_DEP_ANTI and REG_DEP_OUTPUT are used in LOG_LINKS to represent
    write-after-read and write-after-write dependencies respectively.  */
-REG_NOTE (DEP_ANTI)
 REG_NOTE (DEP_OUTPUT)
+REG_NOTE (DEP_ANTI)
 
 /* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs.  It has an
    integer value.  For jumps, it is the probability that this is a

gcc/rtl.def

@@ -93,6 +93,12 @@ DEF_RTL_EXPR(EXPR_LIST, "expr_list", "ee", RTX_EXTRA)
    The insns are represented in print by their uids.  */
 DEF_RTL_EXPR(INSN_LIST, "insn_list", "ue", RTX_EXTRA)
 
+/* a linked list of dependencies. 
+   The insns are represented in print by their uids. 
+   Operand 2 is a degree of speculativeness of the dependence.
+   Operand 3 is a degree of weakness of the dependence.  */
+DEF_RTL_EXPR(DEPS_LIST, "deps_list", "uew", RTX_EXTRA)
+
 /* SEQUENCE appears in the result of a `gen_...' function
    for a DEFINE_EXPAND that wants to make several insns.
    Its elements are the bodies of the insns that should be made.

gcc/rtl.h

@@ -1753,6 +1753,9 @@ void free_EXPR_LIST_node		(rtx);
 void free_INSN_LIST_node		(rtx);
 rtx alloc_INSN_LIST			(rtx, rtx);
 rtx alloc_EXPR_LIST			(int, rtx, rtx);
+void free_DEPS_LIST_list (rtx *);
+rtx alloc_DEPS_LIST (rtx, rtx, HOST_WIDE_INT);
+void remove_free_DEPS_LIST_elem (rtx, rtx *);
 
 /* regclass.c */
 

gcc/sched-ebb.c

@@ -205,7 +205,9 @@ static struct sched_info ebb_sched_info =
 
   NULL, NULL,
   NULL, NULL,
-  0, 1, 0
+  0, 1, 0,
+
+  0
 };
 
 /* It is possible that ebb scheduling eliminated some blocks.
@@ -421,7 +423,7 @@ add_deps_for_risky_insns (rtx head, rtx tail)
   basic_block last_block = NULL, bb;
 
   for (insn = head; insn != next_tail; insn = NEXT_INSN (insn))
-    if (JUMP_P (insn))
+    if (control_flow_insn_p (insn))
       {
 	bb = BLOCK_FOR_INSN (insn);
 	bb->aux = last_block;
@@ -455,9 +457,27 @@ add_deps_for_risky_insns (rtx head, rtx tail)
 	    /* We can not change the mode of the backward
 	       dependency because REG_DEP_ANTI has the lowest
 	       rank.  */
-	    if (! sched_insns_conditions_mutex_p (insn, prev)
-		&& add_dependence (insn, prev, REG_DEP_ANTI))
-	      add_forward_dependence (prev, insn, REG_DEP_ANTI);
+	    if (! sched_insns_conditions_mutex_p (insn, prev))
+	      {
+		if (!(current_sched_info->flags & DO_SPECULATION))
+		  {
+		    enum DEPS_ADJUST_RESULT res;
+		    
+		    res = add_or_update_back_dep (insn, prev,
+						  REG_DEP_ANTI, DEP_ANTI);
+
+		    if (res == DEP_CREATED)
+		      add_forw_dep (insn, LOG_LINKS (insn));
+		    else
+		      gcc_assert (res != DEP_CHANGED);
+		  }
+		else
+		  add_or_update_back_forw_dep (insn, prev, REG_DEP_ANTI,
+					       set_dep_weak (DEP_ANTI,
+							     BEGIN_CONTROL,
+							     MAX_DEP_WEAK));
+	      }
+
             break;
 
           default:
@@ -571,10 +591,12 @@ schedule_ebbs (void)
   if (n_basic_blocks == NUM_FIXED_BLOCKS)
     return;
 
-  sched_init ();
-
+  /* We need current_sched_info in init_dependency_caches, which is
+     invoked via sched_init.  */
   current_sched_info = &ebb_sched_info;
 
+  sched_init ();
+
   compute_bb_for_insn ();
 
   /* Schedule every region in the subroutine.  */

gcc/sched-int.h

@@ -36,6 +36,12 @@ extern state_t curr_state;
 /* Forward declaration.  */
 struct ready_list;
 
+/* Type to represent status of a dependence.  A convinient short alias.  */
+typedef HOST_WIDE_INT ds_t;
+
+/* Type to represent weakness of speculative dependence.  */
+typedef int dw_t;
+
 /* Describe state of dependencies used during sched_analyze phase.  */
 struct deps
 {
@@ -180,6 +186,10 @@ struct sched_info
 
   /* Maximum priority that has been assigned to an insn.  */
   int sched_max_insns_priority;
+
+  /* ??? FIXME: should use straight bitfields inside sched_info instead of
+     this flag field.  */
+  unsigned int flags;
 };
 
 extern struct sched_info *current_sched_info;
@@ -231,6 +241,10 @@ struct haifa_insn_data
 
   /* Nonzero if priority has been computed already.  */
   unsigned int priority_known : 1;
+
+  /* Nonzero if instruction has internal dependence
+     (e.g. add_dependence was invoked with (insn == elem)).  */
+  unsigned int has_internal_dep : 1;
 };
 
 extern struct haifa_insn_data *h_i_d;
@@ -245,6 +259,137 @@ extern struct haifa_insn_data *h_i_d;
 #define INSN_PRIORITY_KNOWN(INSN) (h_i_d[INSN_UID (INSN)].priority_known)
 #define INSN_COST(INSN)		(h_i_d[INSN_UID (INSN)].cost)
 #define INSN_REG_WEIGHT(INSN)	(h_i_d[INSN_UID (INSN)].reg_weight)
+#define HAS_INTERNAL_DEP(INSN)  (h_i_d[INSN_UID (INSN)].has_internal_dep)
+
+/* DEP_STATUS of the link incapsulates information, that is needed for
+   speculative scheduling.  Namely, it is 4 integers in the range
+   [0, MAX_DEP_WEAK] and 3 bits.
+   The integers correspond to the probability of the dependence to *not*
+   exist, it is the probability, that overcoming of this dependence will
+   not be followed by execution of the recovery code.  Nevertheless,
+   whatever high the probability of success is, recovery code should still
+   be generated to preserve semantics of the program.  To find a way to
+   get/set these integers, please refer to the {get, set}_dep_weak ()
+   functions in sched-deps.c .
+   The 3 bits in the DEP_STATUS correspond to 3 dependence types: true-,
+   output- and anti- dependence.  It is not enough for speculative scheduling
+   to know just the major type of all the dependence between two instructions,
+   as only true dependence can be overcome.
+   There also is the 4-th bit in the DEP_STATUS (HARD_DEP), that is reserved
+   for using to describe instruction's status.  It is set whenever instuction
+   has at least one dependence, that cannot be overcome.
+   See also: check_dep_status () in sched-deps.c .  */
+#define DEP_STATUS(LINK) XWINT (LINK, 2)
+
+/* We exclude sign bit.  */
+#define BITS_PER_DEP_STATUS (HOST_BITS_PER_WIDE_INT - 1)
+
+/* First '4' stands for 3 dep type bits and HARD_DEP bit.
+   Second '4' stands for BEGIN_{DATA, CONTROL}, BE_IN_{DATA, CONTROL}
+   dep weakness.  */
+#define BITS_PER_DEP_WEAK ((BITS_PER_DEP_STATUS - 4) / 4)
+
+/* Mask of speculative weakness in dep_status.  */
+#define DEP_WEAK_MASK ((1 << BITS_PER_DEP_WEAK) - 1)
+
+/* This constant means that dependence is fake with 99.999...% probability.
+   This is the maximum value, that can appear in dep_status.
+   Note, that we don't want MAX_DEP_WEAK to be the same as DEP_WEAK_MASK for
+   debugging reasons.  Though, it can be set to DEP_WEAK_MASK, and, when
+   done so, we'll get fast (mul for)/(div by) NO_DEP_WEAK.  */
+#define MAX_DEP_WEAK (DEP_WEAK_MASK - 1)
+
+/* This constant means that dependence is 99.999...% real and it is a really
+   bad idea to overcome it (though this can be done, preserving program
+   semantics).  */
+#define MIN_DEP_WEAK 1
+
+/* This constant represents 100% probability.
+   E.g. it is used to represent weakness of dependence, that doesn't exist.  */
+#define NO_DEP_WEAK (MAX_DEP_WEAK + MIN_DEP_WEAK)
+
+/* Default weakness of speculative dependence.  Used when we can't say
+   neither bad nor good about the dependence.  */
+#define UNCERTAIN_DEP_WEAK (MAX_DEP_WEAK - MAX_DEP_WEAK / 4)
+
+/* Offset for speculative weaknesses in dep_status.  */
+enum SPEC_TYPES_OFFSETS {
+  BEGIN_DATA_BITS_OFFSET = 0,
+  BE_IN_DATA_BITS_OFFSET = BEGIN_DATA_BITS_OFFSET + BITS_PER_DEP_WEAK,
+  BEGIN_CONTROL_BITS_OFFSET = BE_IN_DATA_BITS_OFFSET + BITS_PER_DEP_WEAK,
+  BE_IN_CONTROL_BITS_OFFSET = BEGIN_CONTROL_BITS_OFFSET + BITS_PER_DEP_WEAK
+};
+
+/* The following defines provide numerous constants used to distinguish between
+   different types of speculative dependencies.  */
+
+/* Dependence can be overcomed with generation of new data speculative
+   instruction.  */
+#define BEGIN_DATA (((ds_t) DEP_WEAK_MASK) << BEGIN_DATA_BITS_OFFSET)
+
+/* This dependence is to the instruction in the recovery block, that was
+   formed to recover after data-speculation failure.
+   Thus, this dependence can overcomed with generating of the copy of
+   this instruction in the recovery block.  */
+#define BE_IN_DATA (((ds_t) DEP_WEAK_MASK) << BE_IN_DATA_BITS_OFFSET)
+
+/* Dependence can be overcomed with generation of new control speculative
+   instruction.  */
+#define BEGIN_CONTROL (((ds_t) DEP_WEAK_MASK) << BEGIN_CONTROL_BITS_OFFSET)
+
+/* This dependence is to the instruction in the recovery block, that was
+   formed to recover after control-speculation failure.
+   Thus, this dependence can overcomed with generating of the copy of
+   this instruction in the recovery block.  */
+#define BE_IN_CONTROL (((ds_t) DEP_WEAK_MASK) << BE_IN_CONTROL_BITS_OFFSET)
+
+/* Few convinient combinations.  */
+#define BEGIN_SPEC (BEGIN_DATA | BEGIN_CONTROL)
+#define DATA_SPEC (BEGIN_DATA | BE_IN_DATA)
+#define CONTROL_SPEC (BEGIN_CONTROL | BE_IN_CONTROL)
+#define SPECULATIVE (DATA_SPEC | CONTROL_SPEC)
+#define BE_IN_SPEC (BE_IN_DATA | BE_IN_CONTROL)
+
+/* Constants, that are helpful in iterating through dep_status.  */
+#define FIRST_SPEC_TYPE BEGIN_DATA
+#define LAST_SPEC_TYPE BE_IN_CONTROL
+#define SPEC_TYPE_SHIFT BITS_PER_DEP_WEAK
+
+/* Dependence on instruction can be of multiple types
+   (e.g. true and output). This fields enhance REG_NOTE_KIND information
+   of the dependence.  */
+#define DEP_TRUE (((ds_t) 1) << (BE_IN_CONTROL_BITS_OFFSET + BITS_PER_DEP_WEAK))
+#define DEP_OUTPUT (DEP_TRUE << 1)
+#define DEP_ANTI (DEP_OUTPUT << 1)
+
+#define DEP_TYPES (DEP_TRUE | DEP_OUTPUT | DEP_ANTI)
+
+/* Instruction has non-speculative dependence.  This bit represents the
+   property of an instruction - not the one of a dependence.
+   Therefore, it can appear only in TODO_SPEC field of an instruction.  */
+#define HARD_DEP (DEP_ANTI << 1)
+
+/* This represents the results of calling sched-deps.c functions, 
+   which modify dependencies.  Possible choices are: a dependence
+   is already present and nothing has been changed; a dependence type
+   has been changed; brand new dependence has been created.  */
+enum DEPS_ADJUST_RESULT {
+  DEP_PRESENT = 1,
+  DEP_CHANGED = 2,
+  DEP_CREATED = 3
+};
+
+/* Represents the bits that can be set in the flags field of the 
+   sched_info structure.  */
+enum SCHED_FLAGS {
+  /* If set, generate links between instruction as DEPS_LIST.
+     Otherwise, generate usual INSN_LIST links.  */
+  USE_DEPS_LIST = 1,
+  /* Perform data or control (or both) speculation.
+     Results in generation of data and control speculative dependencies.
+     Requires USE_DEPS_LIST set.  */
+  DO_SPECULATION = USE_DEPS_LIST << 1
+};
 
 extern FILE *sched_dump;
 extern int sched_verbose;
@@ -332,17 +477,23 @@ extern void print_insn (char *, rtx, int);
 
 /* Functions in sched-deps.c.  */
 extern bool sched_insns_conditions_mutex_p (rtx, rtx);
-extern int add_dependence (rtx, rtx, enum reg_note);
+extern void add_dependence (rtx, rtx, enum reg_note);
 extern void sched_analyze (struct deps *, rtx, rtx);
 extern void init_deps (struct deps *);
 extern void free_deps (struct deps *);
 extern void init_deps_global (void);
 extern void finish_deps_global (void);
-extern void add_forward_dependence (rtx, rtx, enum reg_note);
+extern void add_forw_dep (rtx, rtx);
 extern void compute_forward_dependences (rtx, rtx);
 extern rtx find_insn_list (rtx, rtx);
 extern void init_dependency_caches (int);
 extern void free_dependency_caches (void);
+extern enum DEPS_ADJUST_RESULT add_or_update_back_dep (rtx, rtx, 
+						       enum reg_note, ds_t);
+extern void add_or_update_back_forw_dep (rtx, rtx, enum reg_note, ds_t);
+extern void add_back_forw_dep (rtx, rtx, enum reg_note, ds_t);
+extern void delete_back_forw_dep (rtx, rtx);
+extern ds_t set_dep_weak (ds_t, ds_t, dw_t);
 
 /* Functions in haifa-sched.c.  */
 extern int haifa_classify_insn (rtx);

gcc/sched-rgn.c

@@ -1816,7 +1816,9 @@ static struct sched_info region_sched_info =
 
   NULL, NULL,
   NULL, NULL,
-  0, 0, 0
+  0, 0, 0,
+
+  0
 };
 
 /* Determine if PAT sets a CLASS_LIKELY_SPILLED_P register.  */
@@ -2512,6 +2514,11 @@ schedule_insns (void)
 
   nr_inter = 0;
   nr_spec = 0;
+
+  /* We need current_sched_info in init_dependency_caches, which is
+     invoked via sched_init.  */
+  current_sched_info = &region_sched_info;
+
   sched_init ();
 
   min_spec_prob = ((PARAM_VALUE (PARAM_MIN_SPEC_PROB) * REG_BR_PROB_BASE)
@@ -2519,7 +2526,6 @@ schedule_insns (void)
 
   init_regions ();
 
-  current_sched_info = &region_sched_info;
   /* Schedule every region in the subroutine.  */
   for (rgn = 0; rgn < nr_regions; rgn++)
     schedule_region (rgn);