On Wed, Aug 2, 2017 at 1:20 PM, Martin Liška <mli...@suse.cz> wrote: > Hello. > > After some discussions with Honza, I've decided to convert current code in > stmt.c that > is responsible for switch expansion. More precisely, I would like to convert > the code > to expand gswitch statements on tree level. Currently the newly created pass > is executed > at the end of tree optimizations. > > My plan for future is to inspire in [1] and come up with some more > sophisticated switch > expansions. For that I've been working on a paper where I'll summarize > statistics based > on what I've collected in openSUSE distribution with specially instrumented > GCC. If I'll be > happy I can also fit in to schedule of this year's Cauldron with a talk. > > Patch can bootstrap on ppc64le-redhat-linux and survives regression tests. > > Thoughts?
First of all thanks. I think part of switch expansion moved to switch-conversion some time ago (emit_case_bit_tests). So maybe the full lowering should be in at least the same source file and it should maybe applied earlier for a subset of cases (very low number of cases for example). Did you base the code on the RTL expansion code or did you re-write it from scratch? No further comments sofar. Richard. > Martin > > [1] https://www.nextmovesoftware.com/technology/SwitchOptimization.pdf > > gcc/ChangeLog: > > 2017-07-31 Martin Liska <mli...@suse.cz> > > * Makefile.in: Add gimple-switch-low.o. > * passes.def: Include pass_lower_switch. > * stmt.c (dump_case_nodes): Remove and move to > gimple-switch-low.c. > (case_values_threshold): Likewise. > (expand_switch_as_decision_tree_p): Likewise. > (emit_case_decision_tree): Likewise. > (expand_case): Likewise. > (balance_case_nodes): Likewise. > (node_has_low_bound): Likewise. > (node_has_high_bound): Likewise. > (node_is_bounded): Likewise. > (emit_case_nodes): Likewise. > * timevar.def: Add TV_TREE_SWITCH_LOWERING. > * tree-pass.h: Add make_pass_lower_switch. > * gimple-switch-low.c: New file. > > gcc/testsuite/ChangeLog: > > 2017-07-31 Martin Liska <mli...@suse.cz> > > * gcc.dg/tree-prof/update-loopch.c: Scan patterns in > switchlower. > * gcc.dg/tree-ssa/vrp104.c: Likewise. > --- > gcc/Makefile.in | 1 + > gcc/gimple-switch-low.c | 1226 > ++++++++++++++++++++++++ > gcc/passes.def | 1 + > gcc/stmt.c | 861 ----------------- > gcc/testsuite/gcc.dg/tree-prof/update-loopch.c | 10 +- > gcc/testsuite/gcc.dg/tree-ssa/vrp104.c | 2 +- > gcc/timevar.def | 1 + > gcc/tree-pass.h | 1 + > 8 files changed, 1236 insertions(+), 867 deletions(-) > create mode 100644 gcc/gimple-switch-low.c > >
