https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103278
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|rguenth at gcc dot gnu.org |unassigned at gcc dot
gnu.org
Status|RESOLVED |NEW
Resolution|FIXED |---
--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
So for
rl78-elf
if-to-switch-5
we fail the JT because it's not enabled for the target. w/o the CD-DCE change
we build a bit-test from
;; Canonical GIMPLE case clusters: 34 39 44 46 58 59 60 62 92
which we then expand into a new switch without any bit tests(?).
After the CD-DCE change we have improved(?) clusters:
;; Canonical GIMPLE case clusters: 34 39 44 46 58-60 62 92
and thus the output is no longer(?) beneficial.
I wonder if the merging of clusters done as part of the sorting is
counter-productive since it distorts the profitability? If we check against
the
size of the unmerged clusters like with the following the testcase
will pass again. I also notice we don't take advantage of the
merging and create
switch (c_3(D)) <default: <L13> [INV], case 34: <L12> [INV], case 39: <L12>
[INV], case 44: <L12> [INV], case 46: <L12> [INV], case 58: <L12> [INV], case
59: <L12> [INV], case 60: <L12> [INV], case 62: <L12> [INV], case 92: <L12>
[INV]>
instead of one 'case 58-60:'
diff --git a/gcc/gimple-if-to-switch.cc b/gcc/gimple-if-to-switch.cc
index 16fabef7ca0..b64a1915e15 100644
--- a/gcc/gimple-if-to-switch.cc
+++ b/gcc/gimple-if-to-switch.cc
@@ -240,7 +240,7 @@ if_chain::is_beneficial ()
vec<cluster *> output
= jump_table_cluster::find_jump_tables (filtered_clusters);
- bool r = output.length () < filtered_clusters.length ();
+ bool r = output.length () < clusters.length ();
if (r)
{
dump_clusters (&output, "JT can be built");
@@ -251,7 +251,7 @@ if_chain::is_beneficial ()
output.release ();
output = bit_test_cluster::find_bit_tests (filtered_clusters);
- r = output.length () < filtered_clusters.length ();
+ r = output.length () < clusters.length ();
if (r)
dump_clusters (&output, "BT can be built");
Martin, can you please look into this?
