https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86928
Andrey Belevantsev <abel at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |abel at gcc dot gnu.org,
| |amonakov at gcc dot gnu.org
--- Comment #2 from Andrey Belevantsev <abel at gcc dot gnu.org> ---
We're not somehow updating liveness information at all times when we change
control flow. E.g. we do update liveness in sel_split_edge, but not in
sel_redirect_edge_and_branch{,force} hooks, when we're making a new jump and
resetting liveness on the bb it ended up in. This leaves us with the unknown
lv set, and later breaks when we're computing liveness from the other region
and come to this block, as we're assuming that other regions always have
correct liveness.
Fixed with the below patch but I'm not completely sure it fully makes sense --
Alexander, thoughts?
diff --git a/gcc/sel-sched-ir.c b/gcc/sel-sched-ir.c
index 85ff5bd3eb4..c399c1117a3 100644
--- a/gcc/sel-sched-ir.c
+++ b/gcc/sel-sched-ir.c
@@ -5642,6 +5642,8 @@ sel_redirect_edge_and_branch_force (edge e, basic_block
to)
recompute_dominator (CDI_DOMINATORS, to));
set_immediate_dominator (CDI_DOMINATORS, orig_dest,
recompute_dominator (CDI_DOMINATORS, orig_dest));
+ if (jump == sel_bb_head (BLOCK_FOR_INSN (jump)))
+ compute_live (jump);
}
/* A wrapper for redirect_edge_and_branch. Return TRUE if blocks connected by
@@ -5702,6 +5704,8 @@ sel_redirect_edge_and_branch (edge e, basic_block to)
set_immediate_dominator (CDI_DOMINATORS, orig_dest,
recompute_dominator (CDI_DOMINATORS,
orig_dest));
}
+ if (jump == sel_bb_head (BLOCK_FOR_INSN (jump)))
+ compute_live (jump);
return recompute_toporder_p;
}
