(loop_number_exit_count): New global variable.

(loop_optimize): Allocate space for it.
(find_and_verify_loops, mark_loop_jump): Set it.
(strength_reduce, check_dbra_loop): Use loop_number_exit_count instead
of loop_number_exit_labels.

From-SVN: r10128

diff --git a/gcc/loop.c b/gcc/loop.c
index 02caf0124f5f4c79d5691a51bfdbfa346b1a2595..027e1aa9e8d234d439357d09259aa2368612a267 100644 (file)
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -97,6 +97,11 @@ static char *loop_invalid;
 
 rtx *loop_number_exit_labels;
 
+/* Indexed by loop number, counts the number of LABEL_REFs on
+   loop_number_exit_labels for this loop and all loops nested inside it.  */
+
+int *loop_number_exit_count;
+
 /* Holds the number of loop iterations.  It is zero if the number could not be
    calculated.  Must be unsigned since the number of iterations can
    be as high as 2^wordsize-1.  For loops with a wider iterator, this number
@@ -372,6 +377,7 @@ loop_optimize (f, dumpfile)
   loop_outer_loop = (int *) alloca (max_loop_num * sizeof (int));
   loop_invalid = (char *) alloca (max_loop_num * sizeof (char));
   loop_number_exit_labels = (rtx *) alloca (max_loop_num * sizeof (rtx));
+  loop_number_exit_count = (int *) alloca (max_loop_num * sizeof (int));
 
   /* Find and process each loop.
      First, find them, and record them in order of their beginnings.  */
@@ -2240,6 +2246,7 @@ find_and_verify_loops (f)
            loop_outer_loop[next_loop] = current_loop;
            loop_invalid[next_loop] = 0;
            loop_number_exit_labels[next_loop] = 0;
+           loop_number_exit_count[next_loop] = 0;
            current_loop = next_loop;
            break;
 
@@ -2407,6 +2414,8 @@ find_and_verify_loops (f)
                          LABEL_OUTSIDE_LOOP_P bit.  */
                       if (JUMP_LABEL (insn))
                         {
+                          int loop_num;
+
                           for (q = 0,
                                r = loop_number_exit_labels[this_loop_num];
                                r; q = r, r = LABEL_NEXTREF (r))
@@ -2421,6 +2430,11 @@ find_and_verify_loops (f)
                                 break;
                               }
 
+                          for (loop_num = this_loop_num;
+                               loop_num != -1 && loop_num != target_loop_num;
+                               loop_num = loop_outer_loop[loop_num])
+                            loop_number_exit_count[loop_num]--;
+
                           /* If we didn't find it, then something is wrong. */
                           if (! r)
                             abort ();
@@ -2513,6 +2527,11 @@ mark_loop_jump (x, loop_num)
          LABEL_OUTSIDE_LOOP_P (x) = 1;
          LABEL_NEXTREF (x) = loop_number_exit_labels[loop_num];
          loop_number_exit_labels[loop_num] = x;
+
+         for (outer_loop = loop_num;
+              outer_loop != -1 && outer_loop != dest_loop;
+              outer_loop = loop_outer_loop[outer_loop])
+           loop_number_exit_count[outer_loop]++;
        }
 
       /* If this is inside a loop, but not in the current loop or one enclosed
@@ -2569,8 +2588,13 @@ mark_loop_jump (x, loop_num)
         as a branch out of this loop, but not into any loop.  */
 
       if (loop_num != -1)
-       loop_number_exit_labels[loop_num] = x;
+       {
+         loop_number_exit_labels[loop_num] = x;
 
+         for (outer_loop = loop_num; outer_loop != -1;
+              outer_loop = loop_outer_loop[outer_loop])
+           loop_number_exit_count[outer_loop]++;
+       }
       return;
     }
 }
@@ -3905,7 +3929,7 @@ strength_reduce (scan_start, end, loop_top, insn_count,
                 loop to ensure that it will always be executed no matter
                 how the loop exits.  Otherwise, emit the insn after the loop,
                 since this is slightly more efficient.  */
-             if (loop_number_exit_labels[uid_loop_num[INSN_UID (loop_start)]])
+             if (loop_number_exit_count[uid_loop_num[INSN_UID (loop_start)]])
                insert_before = loop_start;
              else
                insert_before = end_insert_before;
@@ -3997,7 +4021,7 @@ strength_reduce (scan_start, end, loop_top, insn_count,
                 loop to ensure that it will always be executed no matter
                 how the loop exits.  Otherwise, emit the insn after the
                 loop, since this is slightly more efficient.  */
-             if (loop_number_exit_labels[uid_loop_num[INSN_UID (loop_start)]])
+             if (loop_number_exit_count[uid_loop_num[INSN_UID (loop_start)]])
                insert_before = loop_start;
              else
                insert_before = end_insert_before;
@@ -5712,7 +5736,7 @@ check_dbra_loop (loop_end, insn_count, loop_start)
          num_nonfixed_reads += count_nonfixed_reads (PATTERN (p));
 
       if (bl->giv_count == 0
-         && ! loop_number_exit_labels[uid_loop_num[INSN_UID (loop_start)]])
+         && ! loop_number_exit_count[uid_loop_num[INSN_UID (loop_start)]])
        {
          rtx bivreg = regno_reg_rtx[bl->regno];