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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/103278] [12 Regression] Recent change to cddce inhibits switch optimization Date: Tue, 23 Nov 2021 08:23:03 +0000 [thread overview] Message-ID: <bug-103278-4-nQlhS8sXf5@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-103278-4@http.gcc.gnu.org/bugzilla/> 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?
next prev parent reply other threads:[~2021-11-23 8:23 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-16 17:16 [Bug tree-optimization/103278] New: " law at gcc dot gnu.org 2021-11-16 23:25 ` [Bug tree-optimization/103278] " pinskia at gcc dot gnu.org 2021-11-16 23:29 ` pinskia at gcc dot gnu.org 2021-11-17 14:48 ` law at gcc dot gnu.org 2021-11-18 7:36 ` rguenth at gcc dot gnu.org 2021-11-18 8:48 ` rguenth at gcc dot gnu.org 2021-11-18 9:02 ` cvs-commit at gcc dot gnu.org 2021-11-18 9:04 ` rguenth at gcc dot gnu.org 2021-11-23 3:31 ` law at gcc dot gnu.org 2021-11-23 8:23 ` rguenth at gcc dot gnu.org [this message] 2021-11-23 8:25 ` marxin at gcc dot gnu.org 2021-11-29 15:23 ` marxin at gcc dot gnu.org 2021-11-30 7:22 ` rguenther at suse dot de 2021-11-30 13:48 ` cvs-commit at gcc dot gnu.org 2021-11-30 13:48 ` marxin at gcc dot gnu.org
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