https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82831
--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> ---
So problem is that in pass_reorder_blocks::execute we reorder blocks so that
they are separated to cold and hot partitions. Then cleanup_cfg
(CLEANUP_EXPENSIVE); is called (bb-reorder.c:2593) and we end here:
2324 static vec<basic_block>
2325 find_partition_fixes (bool flag_only)
2326 {
2327 basic_block bb;
2328 vec<basic_block> bbs_in_cold_partition = vNULL;
2329 vec<basic_block> bbs_to_fix = vNULL;
2330 hash_set<basic_block> set;
2331
2332 /* Callers check this. */
2333 gcc_checking_assert (crtl->has_bb_partition);
2334
2335 find_bbs_reachable_by_hot_paths (&set);
2336
2337 FOR_EACH_BB_FN (bb, cfun)
2338 if (!set.contains (bb)
2339 && BB_PARTITION (bb) != BB_COLD_PARTITION)
2340 {
2341 if (flag_only)
2342 error ("non-cold basic block %d reachable only "
2343 "by paths crossing the cold partition", bb->index);
2344 else
2345 BB_SET_PARTITION (bb, BB_COLD_PARTITION);
2346 bbs_to_fix.safe_push (bb);
2347 bbs_in_cold_partition.safe_push (bb);
2348 }
2349
2350 return bbs_to_fix;
2351 }
and we mark one BB in hot partition as COLD. That causes the ICE.
What about something like this:
diff --git a/gcc/basic-block.h b/gcc/basic-block.h
index 5a5ddbfcb6d..5c393efd164 100644
--- a/gcc/basic-block.h
+++ b/gcc/basic-block.h
@@ -506,6 +506,7 @@ ei_cond (edge_iterator ei, edge *p)
insns. */
#define CLEANUP_CFGLAYOUT 32 /* Do cleanup in cfglayout mode. */
#define CLEANUP_CFG_CHANGED 64 /* The caller changed the CFG. */
+#define CLEANUP_NO_PARTITIONING 128 /* Do not try to fix
partitions. */
/* Return true if BB is in a transaction. */
diff --git a/gcc/bb-reorder.c b/gcc/bb-reorder.c
index f7c1f4c971e..20e231739e3 100644
--- a/gcc/bb-reorder.c
+++ b/gcc/bb-reorder.c
@@ -2590,7 +2590,7 @@ pass_reorder_blocks::execute (function *fun)
cfg_layout_initialize (CLEANUP_EXPENSIVE);
reorder_basic_blocks ();
- cleanup_cfg (CLEANUP_EXPENSIVE);
+ cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_NO_PARTITIONING);
FOR_EACH_BB_FN (bb, fun)
if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (fun))
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index 4734d3eae17..84756a542da 100644
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -3011,7 +3011,8 @@ try_optimize_cfg (int mode)
to detect and fix during edge forwarding, and in some cases
is only visible after newly unreachable blocks are deleted,
which will be done in fixup_partitions. */
- fixup_partitions ();
+ if ((mode & CLEANUP_NO_PARTITIONING) == 0)
+ fixup_partitions ();
checking_verify_flow_info ();
}
