On 08/07/2018 05:50 AM, marxin wrote: > This is the most complex patch. It follows original implementation and > does following improvements that were part of original code: > > a) for a node with both children (that don't have children) and only single > case > values handled: emit series of 3 compares and jump to default > b) for a node with only one child (that doesn't have a child) and only single > case values handled: emit 2 compares and jump to default > c) for a node of a range without a child, emit if (index - low) <= (high - > low)) > d) profile emission is precise, taken also from previous implementation > > These changes + VRP should move us back to code quality we had in GCC 8. > > gcc/ChangeLog: > > 2018-08-13 Martin Liska <mli...@suse.cz> > > PR tree-optimization/86847 > * tree-switch-conversion.c (switch_decision_tree::dump_case_nodes): > Dump also subtree probability. > (switch_decision_tree::do_jump_if_equal): New function. > (switch_decision_tree::emit_case_nodes): Handle special > situations in balanced tree that can be emitted much simpler. > Fix calculation of probabilities that happen in tree expansion. > * tree-switch-conversion.h (struct cluster): Add > is_single_value_p. > (struct simple_cluster): Likewise. > (struct case_tree_node): Add new function has_child. > (do_jump_if_equal): New. > > gcc/testsuite/ChangeLog: > > 2018-08-13 Martin Liska <mli...@suse.cz> > > * gcc.dg/tree-ssa/switch-3.c: New test. > * gcc.dg/tree-ssa/vrp105.c: Remove. Presumably the new expansion strategies totally compromise vrp105. Too bad, that test has actually caught oversights a few times for me in recent history. But I can live with it disappearing.
> diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c > index cd771438214..78914bbe81a 100644 > --- a/gcc/tree-switch-conversion.c > +++ b/gcc/tree-switch-conversion.c > @@ -2054,6 +2056,33 @@ switch_decision_tree::emit_cmp_and_jump_insns > (basic_block bb, tree op0, > return false_edge->dest; > } > > +/* Generate code to jump to LABEL if OP0 and OP1 are equal in mode MODE. > + PROB is the probability of jumping to LABEL_BB. */ > + > +basic_block > +switch_decision_tree::do_jump_if_equal (basic_block bb, tree op0, tree op1, > + basic_block label_bb, > + profile_probability prob) MODE isn't a parameter and probably shouldn't show up in the function comment. Please document BB in the function comment. OK with the comment fix. jeff
