On 08/02/2017 01:51 PM, Richard Biener wrote: > 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).
Yep, good idea. I'll take a look. > > Did you base the code on the RTL expansion code or did you re-write it from > scratch? It's based, I've just changed the function that create CFG. Martin > > 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 >> >>
