(find_and_verify_loops): When moving blocks of code, verify that the just destination...

(find_and_verify_loops): When moving blocks of code, verify that the
just destination is not in an inner nested loop.
(mark_loop_jump): Don't mark label as loop exit if it jumps to an
inner nested loop.

From-SVN: r10164

diff --git a/gcc/loop.c b/gcc/loop.c
index 027e1aa9e8d234d439357d09259aa2368612a267..2729450a389dfffd70c90dc489a5fe29bc9975f3 100644 (file)
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -2338,6 +2338,8 @@ find_and_verify_loops (f)
          {
            rtx p;
            rtx our_next = next_real_insn (insn);
+           int dest_loop = uid_loop_num[INSN_UID (JUMP_LABEL (insn))];
+           int outer_loop;
 
            /* Go backwards until we reach the start of the loop, a label,
               or a JUMP_INSN.  */
@@ -2349,6 +2351,19 @@ find_and_verify_loops (f)
                 p = PREV_INSN (p))
              ;
 
+           /* Check for the case where we have a jump to an inner nested
+              loop, and do not perform the optimization in that case.  */
+
+           if (dest_loop != -1)
+             {
+               for (outer_loop = dest_loop; outer_loop != -1;
+                    outer_loop = loop_outer_loop[outer_loop])
+                 if (outer_loop == this_loop_num)
+                   break;
+             }
+           else
+             outer_loop = -1;
+
            /* If we stopped on a JUMP_INSN to the next insn after INSN,
               we have a block of code to try to move.
 
@@ -2358,7 +2373,8 @@ find_and_verify_loops (f)
               of the block, invert the jump in P and point it to that label,
               and move the block of code to the spot we found.  */
 
-           if (GET_CODE (p) == JUMP_INSN
+           if (outer_loop == -1
+               && GET_CODE (p) == JUMP_INSN
                && JUMP_LABEL (p) != 0
                /* Just ignore jumps to labels that were never emitted.
                   These always indicate compilation errors.  */
@@ -2522,7 +2538,19 @@ mark_loop_jump (x, loop_num)
         mark this LABEL_REF so we know that this branch should predict
         false.  */
 
-      if (dest_loop != loop_num && loop_num != -1)
+      /* A check to make sure the label is not in an inner nested loop,
+        since this does not count as a loop exit.  */
+      if (dest_loop != -1)
+       {
+         for (outer_loop = dest_loop; outer_loop != -1;
+              outer_loop = loop_outer_loop[outer_loop])
+           if (outer_loop == loop_num)
+             break;
+       }
+      else
+       outer_loop = -1;
+
+      if (loop_num != -1 && outer_loop == -1)
        {
          LABEL_OUTSIDE_LOOP_P (x) = 1;
          LABEL_NEXTREF (x) = loop_number_exit_labels[loop_num];