The following patch adds checking to calculate_dominance_info that
if we re-use existing dominance info it is correct (unsurprisingly
this wasn't always the case, noticed when using verify_loop_structure
in random places ...).
Bootstrap and regtest pending on x86_64-unknown-linux-gnu.
Do people think the extra checking is worth its time? We might
want to drop other explicit calls to verify_dominators (we currently
do not assert we drop post-dom info and nowhere verify post-dom
info for example).
I've been unconditionally checking loop structure and dominator info
if they are available after each pass, from the pass manager
(I think the TODO_verify_* bits are odd, I mean, that passes can
opt-out from being verified ... OTOH between IRA and reload we
have loop info but it breaks (sometimes at least))
Thanks,
Richard.
2012-03-05 Richard Guenther <rguent...@suse.de>
* cfgexpand.c (gimple_expand_cfg): Free dominator info.
* cfgloop.c (verify_loop_structure): Compute dominator info.
* dominance.c (calculate_dominance_info): If we re-use existing
computed dominance info, verify if it is correct.
* tree-if-conv.c (combine_blocks): Free post-dominator info
after breaking it.
* tree-parloops.c (create_parallel_loop): Free and re-compute
dominator info after breaking it.
Index: gcc/cfgexpand.c
===================================================================
*** gcc/cfgexpand.c.orig 2012-02-23 13:24:54.000000000 +0100
--- gcc/cfgexpand.c 2012-02-23 14:16:43.000000000 +0100
*************** gimple_expand_cfg (void)
*** 4362,4367 ****
--- 4369,4376 ----
/* Some backends want to know that we are expanding to RTL. */
currently_expanding_to_rtl = 1;
+ /* Dominators are not kept up-to-date as we may create new basic-blocks. */
+ free_dominance_info (CDI_DOMINATORS);
rtl_profile_for_bb (ENTRY_BLOCK_PTR);
Index: gcc/cfgloop.c
===================================================================
*** gcc/cfgloop.c.orig 2012-02-23 13:24:54.000000000 +0100
--- gcc/cfgloop.c 2012-02-23 14:06:15.000000000 +0100
*************** verify_loop_structure (void)
*** 1317,1322 ****
--- 1317,1326 ----
unsigned num = number_of_loops ();
loop_iterator li;
struct loop_exit *exit, *mexit;
+ bool dom_available = dom_info_available_p (CDI_DOMINATORS);
+
+ /* Ensure that the dominators are computed. */
+ calculate_dominance_info (CDI_DOMINATORS);
/* Check sizes. */
sizes = XCNEWVEC (unsigned, num);
*************** verify_loop_structure (void)
*** 1560,1565 ****
--- 1572,1579 ----
gcc_assert (!err);
free (sizes);
+ if (!dom_available)
+ free_dominance_info (CDI_DOMINATORS);
}
/* Returns latch edge of LOOP. */
Index: gcc/dominance.c
===================================================================
*** gcc/dominance.c.orig 2012-02-23 13:24:54.000000000 +0100
--- gcc/dominance.c 2012-02-23 14:06:15.000000000 +0100
*************** calculate_dominance_info (enum cdi_direc
*** 639,645 ****
bool reverse = (dir == CDI_POST_DOMINATORS) ? true : false;
if (dom_computed[dir_index] == DOM_OK)
! return;
timevar_push (TV_DOMINANCE);
if (!dom_info_available_p (dir))
--- 639,650 ----
bool reverse = (dir == CDI_POST_DOMINATORS) ? true : false;
if (dom_computed[dir_index] == DOM_OK)
! {
! #ifdef ENABLE_CHECKING
! verify_dominators (dir);
! #endif
! return;
! }
timevar_push (TV_DOMINANCE);
if (!dom_info_available_p (dir))
*************** calculate_dominance_info (enum cdi_direc
*** 667,672 ****
--- 672,681 ----
free_dom_info (&di);
dom_computed[dir_index] = DOM_NO_FAST_QUERY;
}
+ #ifdef ENABLE_CHECKING
+ else
+ verify_dominators (dir);
+ #endif
compute_dom_fast_query (dir);
Index: gcc/tree-if-conv.c
===================================================================
*** gcc/tree-if-conv.c.orig 2012-02-23 13:24:54.000000000 +0100
--- gcc/tree-if-conv.c 2012-02-23 14:06:15.000000000 +0100
*************** combine_blocks (struct loop *loop)
*** 1712,1717 ****
--- 1712,1720 ----
free (ifc_bbs);
ifc_bbs = NULL;
+
+ /* Post-dominators are corrupt now. */
+ free_dominance_info (CDI_POST_DOMINATORS);
}
/* If-convert LOOP when it is legal. For the moment this pass has no
Index: gcc/tree-parloops.c
===================================================================
*** gcc/tree-parloops.c.orig 2012-02-23 13:24:54.000000000 +0100
--- gcc/tree-parloops.c 2012-02-23 14:06:15.000000000 +0100
*************** create_parallel_loop (struct loop *loop,
*** 1740,1745 ****
--- 1740,1749 ----
gimple_set_location (stmt, loc);
gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+ /* After the above dom info is hosed. Re-compute it. */
+ free_dominance_info (CDI_DOMINATORS);
+ calculate_dominance_info (CDI_DOMINATORS);
+
return paral_bb;
}
