On 08/30/2017 02:56 PM, Richard Biener wrote: > On Wed, Aug 30, 2017 at 2:32 PM, Martin Liška <mli...@suse.cz> wrote: >> On 08/30/2017 02:28 PM, Richard Biener wrote: >>> On Wed, Aug 30, 2017 at 1:13 PM, Martin Liška <mli...@suse.cz> wrote: >>>> Hi. >>>> >>>> Simple transformation of switch statements where degenerated switch can be >>>> interpreted >>>> as gimple condition (or removed if having any non-default case). I >>>> originally though >>>> that we don't have switch statements without non-default cases, but >>>> PR82032 shows we >>>> can see it. >>>> >>>> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests. >>>> >>>> Ready to be installed? >>> >>> While I guess this case is ok to handle here it would be nice if CFG cleanup >>> would do the same. I suppose find_taken_edge somehow doesn't work for >>> this case even after my last enhancement? Or is CFG cleanup for some reason >>> not run? >> >> Do you mean both with # of non-default edges equal to 0 and 1? >> Let me take a look. > > First and foremost 0. The case of 1 non-default and a default would > need extra code.
For the test-case I reduced, one needs: diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c index b7593068ea9..13af516c6ac 100644 --- a/gcc/tree-cfg.c +++ b/gcc/tree-cfg.c @@ -8712,7 +8712,7 @@ const pass_data pass_data_split_crit_edges = PROP_no_crit_edges, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ - 0, /* todo_flags_finish */ + TODO_cleanup_cfg, /* todo_flags_finish */ }; class pass_split_crit_edges : public gimple_opt_pass And the code eliminates the problematic switch statement. Do you believe it's the right approach to add the clean up and preserve the assert in tree-switch-conversion.c? For the case with # of edges == 1, should I place it to tree-cfg.c in order to trigger it as a clean-up? Thoughts? Martin > > Richard. > >> Martin >> >>> >>> Richard. >>> >>>> Martin >>>> >>>> gcc/ChangeLog: >>>> >>>> 2017-08-25 Martin Liska <mli...@suse.cz> >>>> >>>> PR tree-optimization/82032 >>>> * tree-switch-conversion.c (generate_high_low_equality): New >>>> function. >>>> (expand_degenerated_switch): Likewise. >>>> (process_switch): Call expand_degenerated_switch. >>>> (try_switch_expansion): Likewise. >>>> (emit_case_nodes): Use generate_high_low_equality. >>>> >>>> gcc/testsuite/ChangeLog: >>>> >>>> 2017-08-25 Martin Liska <mli...@suse.cz> >>>> >>>> PR tree-optimization/82032 >>>> * gcc.dg/tree-ssa/pr68198.c: Update jump threading expectations. >>>> * gcc.dg/tree-ssa/switch-expansion.c: New test. >>>> * gcc.dg/tree-ssa/vrp34.c: Update scanned pattern. >>>> * g++.dg/other/pr82032.C: New test. >>>> --- >>>> gcc/testsuite/g++.dg/other/pr82032.C | 36 +++++++ >>>> gcc/testsuite/gcc.dg/tree-ssa/pr68198.c | 6 +- >>>> gcc/testsuite/gcc.dg/tree-ssa/switch-expansion.c | 14 +++ >>>> gcc/testsuite/gcc.dg/tree-ssa/vrp34.c | 5 +- >>>> gcc/tree-switch-conversion.c | 123 >>>> ++++++++++++++++++----- >>>> 5 files changed, 152 insertions(+), 32 deletions(-) >>>> create mode 100644 gcc/testsuite/g++.dg/other/pr82032.C >>>> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/switch-expansion.c >>>> >>>> >>
