I've bootstrapped and tested the following on 4.9-branch. It's a
backport of a patch that avoids unnecessary assertion failures, both by
tuning down an assert, and restricting an optimization for the case
where the assert would validly trigger.
Ok to commit on the branch?
Bernd
PR target/63681
* cfgrtl.c (cfg_layout_initialize): Weaken assert to only trigger if
flag_reorder_blocks_and_partition.
* hw-doloop.c (reorg_loops): Avoid reordering if that flag is set.
diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 1a63249..2d75845 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -4222,14 +4222,14 @@ cfg_layout_initialize (unsigned int flags)
rtx x;
basic_block bb;
- /* Once bb reordering is complete, cfg layout mode should not be re-entered.
- Entering cfg layout mode will perform optimizations on the cfg that
- could affect the bb layout negatively or even require fixups. An
- example of the latter is if edge forwarding performed when optimizing
- the cfg layout required moving a block from the hot to the cold section
- under -freorder-blocks-and-partition. This would create an illegal
- partitioning unless some manual fixup was performed. */
- gcc_assert (!crtl->bb_reorder_complete);
+ /* Once bb partitioning is complete, cfg layout mode should not be
+ re-entered. Entering cfg layout mode may require fixups. As an
+ example, if edge forwarding performed when optimizing the cfg
+ layout required moving a block from the hot to the cold
+ section. This would create an illegal partitioning unless some
+ manual fixup was performed. */
+ gcc_assert (!(crtl->bb_reorder_complete
+ && flag_reorder_blocks_and_partition));
initialize_original_copy_tables ();
diff --git a/gcc/hw-doloop.c b/gcc/hw-doloop.c
index b6184a2..9c2c874 100644
--- a/gcc/hw-doloop.c
+++ b/gcc/hw-doloop.c
@@ -636,7 +636,9 @@ reorg_loops (bool do_reorder, struct hw_doloop_hooks *hooks)
loops = discover_loops (&loop_stack, hooks);
- if (do_reorder)
+ /* We can't enter cfglayout mode anymore if basic block partitioning
+ already happened. */
+ if (do_reorder && !flag_reorder_blocks_and_partition)
{
reorder_loops (loops);
free_loops (loops);
