On 11/9/20 4:56 PM, Jeff Law wrote:
On 11/9/20 7:24 AM, Martin Liška wrote:
Hello.
As mentioned in the PR, we used to prefer BT over JT in switch expansion.
I restore the behavior to that.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
gcc/ChangeLog:
    PR tree-optimization/97736
    * tree-switch-conversion.c
(switch_decision_tree::analyze_switch_statement):
    Prefer bit tests.
gcc/testsuite/ChangeLog:
    PR tree-optimization/97736
    * gcc.dg/tree-ssa/switch-1.c: Prefer bit tests.
    * g++.dg/tree-ssa/pr97736.C: New test.
[ ... ]
---
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c
index 426462e856b..a7c5df31743 100644
--- a/gcc/tree-switch-conversion.c
+++ b/gcc/tree-switch-conversion.c
@@ -1743,8 +1743,8 @@ switch_decision_tree::analyze_switch_statement ()
Â
  reset_out_edges_aux (m_switch);
Â
- /* Find jump table clusters. */
-Â vec<cluster *> output = jump_table_cluster::find_jump_tables
(clusters);
+ /* Find bit-test clusters. */
+Â vec<cluster *> output = bit_test_cluster::find_bit_tests (clusters);
Â
  /* Find bit test clusters. */
               ^^^
Doesn't the "bit test clusters" need to change too? OK with that nit fixed.
Yep, fixed that.
Btw. Jeff, I noticed your email client is sending weird 'Â' characters as can
be seen also here:
https://gcc.gnu.org/pipermail/gcc-patches/2020-November/558502.html
Can you please take a look?
Thanks,
Martin
jeff
