[PATCH] Fix PR59890, improve var-tracking compile-time

[Richard Biener]

This improves var-tracking dataflow convergence by using post order
on the inverted CFG - which is appropriate for forward dataflow
problems.  This haves compile-time spent in var-tracking for PR45364
(it also improves other testcases, but that one seems to be the best 
case).

For this to pass bootstrap I had to fix PR59890, two latent
bugs with the recently added local_get_addr_cache.

Bootstrapped and tested on x86_64-unknown-linux-gnu, ok for trunk?

Thanks,
Richard.

2014-01-20  Richard Biener  <rguent...@suse.de>

        PR rtl-optimization/45364
        PR rtl-optimization/59890
        * var-tracking.c (local_get_addr_clear_given_value): Handle
        already cleared slot.
        (val_reset): Handle not allocated local_get_addr_cache.
        (vt_find_locations): Use post-order on the inverted CFG.

Index: gcc/var-tracking.c
===================================================================
*** gcc/var-tracking.c  (revision 206808)
--- gcc/var-tracking.c  (working copy)
*************** static bool
*** 2481,2487 ****
  local_get_addr_clear_given_value (const void *v ATTRIBUTE_UNUSED,
                                  void **slot, void *x)
  {
!   if (vt_get_canonicalize_base ((rtx)*slot) == x)
      *slot = NULL;
    return true;
  }
--- 2481,2488 ----
  local_get_addr_clear_given_value (const void *v ATTRIBUTE_UNUSED,
                                  void **slot, void *x)
  {
!   if (*slot != NULL
!       && vt_get_canonicalize_base ((rtx)*slot) == x)
      *slot = NULL;
    return true;
  }
*************** val_reset (dataflow_set *set, decl_or_va
*** 2501,2507 ****
  
    gcc_assert (var->n_var_parts == 1);
  
!   if (var->onepart == ONEPART_VALUE)
      {
        rtx x = dv_as_value (dv);
        void **slot;
--- 2502,2509 ----
  
    gcc_assert (var->n_var_parts == 1);
  
!   if (var->onepart == ONEPART_VALUE
!       && local_get_addr_cache != NULL)
      {
        rtx x = dv_as_value (dv);
        void **slot;
*************** vt_find_locations (void)
*** 6934,6945 ****
    bool success = true;
  
    timevar_push (TV_VAR_TRACKING_DATAFLOW);
!   /* Compute reverse completion order of depth first search of the CFG
       so that the data-flow runs faster.  */
!   rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS);
    bb_order = XNEWVEC (int, last_basic_block_for_fn (cfun));
!   pre_and_rev_post_order_compute (NULL, rc_order, false);
!   for (i = 0; i < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; i++)
      bb_order[rc_order[i]] = i;
    free (rc_order);
  
--- 6936,6947 ----
    bool success = true;
  
    timevar_push (TV_VAR_TRACKING_DATAFLOW);
!   /* Compute reverse top sord order of the inverted CFG
       so that the data-flow runs faster.  */
!   rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun));
    bb_order = XNEWVEC (int, last_basic_block_for_fn (cfun));
!   int num = inverted_post_order_compute (rc_order);
!   for (i = 0; i < num; i++)
      bb_order[rc_order[i]] = i;
    free (rc_order);