* loop.h (struct movables): Remove `num'.

	* loop.c (scan_loop): Don't set it.  Use count_insns_in_loop.
	Adjust call to strength_reduce.
	(num_unmoved_movables): New function.
	(move_movables): Don't set movables->num.
	(strength_reduce): Compute the number of instructions in the loop
	here, rather than in the caller.
	(check_dbra_loop): Always clear reversible_mem_store if there
	are any memory sets.
	(loop_regs_scan): Don't count instructions here.
	(count_insn_in_loop): New function.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@41966 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 66 insertions, 32 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index af101ea6897..9387b95bc73 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,19 @@
 2001-05-11  Mark Mitchell  <mark@codesourcery.com>
 
+	* loop.h (struct movables): Remove `num'.
+	* loop.c (scan_loop): Don't set it.  Use count_insns_in_loop.
+	Adjust call to strength_reduce.
+	(num_unmoved_movables): New function.
+	(move_movables): Don't set movables->num.
+	(strength_reduce): Compute the number of instructions in the loop
+	here, rather than in the caller.
+	(check_dbra_loop): Always clear reversible_mem_store if there
+	are any memory sets.
+	(loop_regs_scan): Don't count instructions here.
+	(count_insn_in_loop): New function.
+
+2001-05-11  Mark Mitchell  <mark@codesourcery.com>
+
 	* optabs.c (emit_libcall_block): Don't mark calls as CONST_CALL_P.
 
 2001-05-11  Neil Booth  <neil@daikokuya.demon.co.uk>
diff --git a/gcc/loop.c b/gcc/loop.c
index fb045123356..4a41c2d32d1 100644
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -165,6 +165,7 @@ static void ignore_some_movables PARAMS ((struct loop_movables *));
 static void force_movables PARAMS ((struct loop_movables *));
 static void combine_movables PARAMS ((struct loop_movables *,
 				      struct loop_regs *));
+static int num_unmoved_movables PARAMS ((const struct loop *));
 static int regs_match_p PARAMS ((rtx, rtx, struct loop_movables *));
 static int rtx_equal_for_loop_p PARAMS ((rtx, rtx, struct loop_movables *,
 					 struct loop_regs *));
@@ -189,7 +190,7 @@ static void loop_givs_reduce PARAMS((struct loop *, struct iv_class *));
 static void loop_givs_rescan PARAMS((struct loop *, struct iv_class *,
 				     rtx *));
 static void loop_ivs_free PARAMS((struct loop *));
-static void strength_reduce PARAMS ((struct loop *, int, int));
+static void strength_reduce PARAMS ((struct loop *, int));
 static void find_single_use_in_loop PARAMS ((struct loop_regs *, rtx, rtx));
 static int valid_initial_value_p PARAMS ((rtx, rtx, int, rtx));
 static void find_mem_givs PARAMS ((const struct loop *, rtx, rtx, int, int));
@@ -232,7 +233,8 @@ static int last_use_this_basic_block PARAMS ((rtx, rtx));
 static void record_initial PARAMS ((rtx, rtx, void *));
 static void update_reg_last_use PARAMS ((rtx, rtx));
 static rtx next_insn_in_loop PARAMS ((const struct loop *, rtx));
-static void loop_regs_scan PARAMS ((const struct loop*, int, int *));
+static void loop_regs_scan PARAMS ((const struct loop *, int));
+static int count_insns_in_loop PARAMS ((const struct loop *));
 static void load_mems PARAMS ((const struct loop *));
 static int insert_loop_mem PARAMS ((rtx *, void *));
 static int replace_loop_mem PARAMS ((rtx *, void *));
@@ -550,7 +552,6 @@ scan_loop (loop, flags)
 
   movables->head = 0;
   movables->last = 0;
-  movables->num = 0;
 
   /* Determine whether this loop starts with a jump down to a test at
      the end.  This will occur for a small number of loops with a test
@@ -637,7 +638,8 @@ scan_loop (loop, flags)
   /* Allocate extra space for REGs that might be created by load_mems.
      We allocate a little extra slop as well, in the hopes that we
      won't have to reallocate the regs array.  */
-  loop_regs_scan (loop, loop_info->mems_idx + 16, &insn_count);
+  loop_regs_scan (loop, loop_info->mems_idx + 16);
+  insn_count = count_insns_in_loop (loop);
 
   if (loop_dump_stream)
     {
@@ -1006,7 +1008,7 @@ scan_loop (loop, flags)
 
   /* Recalculate regs->array if load_mems has created new registers.  */
   if (max_reg_num () > regs->num)
-    loop_regs_scan (loop, 0, &insn_count);
+    loop_regs_scan (loop, 0);
 
   for (update_start = loop_start;
        PREV_INSN (update_start)
@@ -1024,7 +1026,7 @@ scan_loop (loop, flags)
 	/* Ensure our label doesn't go away.  */
 	LABEL_NUSES (update_end)++;
 
-      strength_reduce (loop, insn_count, flags);
+      strength_reduce (loop, flags);
 
       reg_scan_update (update_start, update_end, loop_max_reg);
       loop_max_reg = max_reg_num ();
@@ -1421,6 +1423,24 @@ combine_movables (movables, regs)
   /* Clean up.  */
   free (matched_regs);
 }
+
+/* Returns the number of movable instructions in LOOP that were not
+   moved outside the loop.  */
+
+static int
+num_unmoved_movables (loop)
+     const struct loop *loop;
+{
+  int num = 0;
+  struct movable *m;
+
+  for (m = LOOP_MOVABLES (loop)->head; m; m = m->next)
+    if (!m->done)
+      ++num;
+
+  return num;
+}
+
 
 /* Return 1 if regs X and Y will become the same if moved.  */
 
@@ -1634,8 +1654,6 @@ move_movables (loop, movables, threshold, insn_count)
   rtx *reg_map = (rtx *) xcalloc (nregs, sizeof (rtx));
   char *already_moved = (char *) xcalloc (nregs, sizeof (char));
 
-  movables->num = 0;
-
   for (m = movables->head; m; m = m->next)
     {
       /* Describe this movable insn.  */
@@ -1664,9 +1682,6 @@ move_movables (loop, movables, threshold, insn_count)
 		     INSN_UID (m->forces->insn));
 	}
 
-      /* Count movables.  Value used in heuristics in strength_reduce.  */
-      movables->num++;
-
       /* Ignore the insn if it's already done (it matched something else).
 	 Otherwise, see if it is now safe to move.  */
 
@@ -4200,9 +4215,8 @@ loop_ivs_free (loop)
    must check regnos to make sure they are in bounds.  */
 
 static void
-strength_reduce (loop, insn_count, flags)
+strength_reduce (loop, flags)
      struct loop *loop;
-     int insn_count;
      int flags;
 {
   struct loop_info *loop_info = LOOP_INFO (loop);
@@ -4222,6 +4236,7 @@ strength_reduce (loop, insn_count, flags)
   int reg_map_size;
   int unrolled_insn_copies = 0;
   rtx test_reg = gen_rtx_REG (word_mode, LAST_VIRTUAL_REGISTER + 1);
+  int insn_count = count_insns_in_loop (loop);
 
   addr_placeholder = gen_reg_rtx (Pmode);
 
@@ -7325,12 +7340,11 @@ check_dbra_loop (loop, insn_count)
 	    {
 	      struct induction *v;
 
-	      reversible_mem_store
-		= (! loop_info->unknown_address_altered
-		   && ! loop_info->unknown_constant_address_altered
-		   && ! loop_invariant_p (loop,
-					  XEXP (XEXP (loop_info->store_mems, 0),
-						0)));
+	      /* If we could prove that each of the memory locations
+		 written to was different, then we could reverse the
+		 store -- but we don't presently have any way of
+		 knowing that.  */
+	      reversible_mem_store = 0;
 
 	      /* If the store depends on a register that is set after the
 		 store, it depends on the initial value, and is thus not
@@ -7362,7 +7376,7 @@ check_dbra_loop (loop, insn_count)
 	   && ! loop_info->has_volatile
 	   && reversible_mem_store
 	   && (bl->giv_count + bl->biv_count + loop_info->num_mem_sets
-	       + LOOP_MOVABLES (loop)->num + compare_and_branch == insn_count)
+	       + num_unmoved_movables (loop) + compare_and_branch == insn_count)
 	   && (bl == ivs->list && bl->next == 0))
 	  || no_use_except_counting)
 	{
@@ -8702,16 +8716,12 @@ insert_loop_mem (mem, data)
    parameter may be zero, in which case this processing is not done.
 
    Set REGS->ARRAY[I].MAY_NOT_OPTIMIZE nonzero if we should not
-   optimize register I.
-
-   Store in *COUNT_PTR the number of actual instructions
-   in the loop.  We use this to decide what is worth moving out.  */
+   optimize register I.  */
 
 static void
-loop_regs_scan (loop, extra_size, count_ptr)
+loop_regs_scan (loop, extra_size)
      const struct loop *loop;
      int extra_size;
-     int *count_ptr;
 {
   struct loop_regs *regs = LOOP_REGS (loop);
   int old_nregs;
@@ -8719,7 +8729,6 @@ loop_regs_scan (loop, extra_size, count_ptr)
    basic block.  In that case, it is the insn that last set reg n.  */
   rtx *last_set;
   rtx insn;
-  int count = 0;
   int i;
 
   old_nregs = regs->num;
@@ -8754,8 +8763,6 @@ loop_regs_scan (loop, extra_size, count_ptr)
     {
       if (INSN_P (insn))
 	{
-	  ++count;
-
 	  /* Record registers that have exactly one use.  */
 	  find_single_use_in_loop (regs, insn, PATTERN (insn));
 
@@ -8798,9 +8805,24 @@ loop_regs_scan (loop, extra_size, count_ptr)
     regs->array[i].n_times_set = regs->array[i].set_in_loop;
 
   free (last_set);
-  *count_ptr = count;
 }
 
+/* Returns the number of real INSNs in the LOOP.  */
+
+static int
+count_insns_in_loop (loop)
+     const struct loop *loop;
+{
+  int count = 0;
+  rtx insn;
+
+  for (insn = loop->top ? loop->top : loop->start; insn != loop->end;
+       insn = NEXT_INSN (insn))
+    if (INSN_P (insn))
+      ++count;
+
+  return count;
+}
 
 /* Move MEMs into registers for the duration of the loop.  */
 
diff --git a/gcc/loop.h b/gcc/loop.h
index cfec9934b20..1794730307d 100644
--- a/gcc/loop.h
+++ b/gcc/loop.h
@@ -289,8 +289,6 @@ struct loop_movables
   struct movable *head;
   /* Last movable in chain.  */
   struct movable *last;
-  /* Number of movables in the loop.  */
-  int num;
 };